244 results on '"An, Zhiguo"'
Search Results
2. Guest Solvent-Directed Isomeric Metal–Organic Frameworks for the Kinetically Favorable Separation of Carbon Dioxide and Methane
- Author
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Dan Lai, Fuqiang Chen, Lidong Guo, Lihang Chen, Jie Chen, Qiwei Yang, Zhiguo Zhang, Yiwen Yang, Qilong Ren, and Zongbi Bao
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Guest solvent-directed strategy ,Metal–organic frameworks ,Carbon dioxide ,Methane ,Kinetic separation ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The adsorptive separation of CH4 from CO2 is a promising process for upgrading natural gas. However, thermodynamically selective adsorbents exhibit a strong affinity for CO2 and thus require a high energy compensation for regeneration. Instead, kinetic separation is preferred for a pressure swing adsorption process, although precise control of the aperture size to achieve a tremendous discrepancy in diffusion rates remains challenging. Here, we report a guest solvent-directed strategy for fine-tuning the pore size at a sub-angstrom precision to realize highly efficient kinetic separation. A series of metal–organic frameworks (MOFs) with isomeric pore surface chemistry were constructed from 4,4′-(hexafluoroisopropyli-dene)-bis(benzoic acid) and dicopper paddlewheel notes. The resultant CuFMOF·CH3OH (CuFMOF-c) exhibits an excellent kinetic separation performance thanks to a periodically expanding and contracting aperture with the ideal bottleneck size, which enables the effective trapping of CO2 and impedes the diffusion of CH4, offering an ultrahigh kinetic selectivity (273.5) and equilibrium-kinetic combined selectivity (64.2). Molecular dynamics calculations elucidate the separation mechanism, and breakthrough experiments validate the separation performance.
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- 2023
- Full Text
- View/download PDF
3. Hydrogen-bonded metal-nucleobase frameworks for highly selective capture of ethane/propane from methane and methane/nitrogen separation
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Liu, Ying, Xu, Qianqian, Chen, Lihang, Song, Changhua, Yang, Qiwei, Zhang, Zhiguo, Lu, Dan, Yang, Yiwen, Ren, Qilong, and Bao, Zongbi
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- 2022
- Full Text
- View/download PDF
4. Greenhouse Gases Trade-Off from Ponds: An Overview of Emission Process and Their Driving Factors
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Sandeep K. Malyan, Omkar Singh, Amit Kumar, Gagan Anand, Rajesh Singh, Sandeep Singh, Zhiguo Yu, Jhlaesh Kumar, and Ram K. Fagodiya
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greenhouse gases ,inland water ,ponds ,methane ,carbon dioxide ,climate change ,Hydraulic engineering ,TC1-978 ,Water supply for domestic and industrial purposes ,TD201-500 - Abstract
Inland water bodies (particularly ponds) emit a significant amount of greenhouse gases (GHGs), particularly methane (CH4), carbon dioxide (CO2), and a comparatively low amount of nitrous oxide (N2O) to the atmosphere. In recent decades, ponds (2) probably account for about 1/3rd of the global lake perimeter and are considered a hotspot of GHG emissions. High nutrients and waterlogged conditions provide an ideal environment for CH4 production and emission. The rate of emissions differs according to climatic regions and is influenced by several biotic and abiotic factors, such as temperature, nutrients (C, N, & P), pH, dissolved oxygen, sediments, water depth, etc. Moreover, micro and macro planktons play a significant role in CO2 and CH4 emissions from ponds systems. Generally, in freshwater bodies, the produced N2O diffuses in the water and is converted into N2 gas through different biological processes. There are several other factors and mechanisms which significantly affect the CH4 and CO2 emission rate from ponds and need a comprehensive evaluation. This study aims to develop a decisive understanding of GHG emissions mechanisms, processes, and methods of measurement from ponds. Key factors affecting the emissions rate will also be discussed. This review will be highly useful for the environmentalists, policymakers, and water resources planners and managers to take suitable mitigation measures in advance so that the climatic impact could be reduced in the future.
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- 2022
- Full Text
- View/download PDF
5. Evaluation of offline sampling for atmospheric C3-C11 non-methane hydrocarbons
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Junfeng Liu, Yuzheng Wang, Liu Zhiguo, Yuanyuan Zhang, Chengtang Liu, Chenglong Zhang, Zhouming He, Yujing Mu, and Pengfei Liu
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Air Pollutants ,Chromatography, Gas ,Environmental Engineering ,Materials science ,Analytical chemistry ,Thermal desorption ,Scrubber ,chemistry.chemical_element ,General Medicine ,Carbon ,Hydrocarbons ,Methane ,chemistry.chemical_compound ,Polyvinyl fluoride ,Adsorption ,Fluorinated ethylene propylene ,chemistry ,Environmental Chemistry ,Pyrolysis ,Environmental Monitoring ,General Environmental Science - Abstract
The concentration variation of C3-C11 non-methane hydrocarbons (NMHCs) collected in several types of commercial flexible bags and adsorption tubes was systematically investigated using a gas chromatography-flame ionization detector (GC-FID) system. The percentage loss of each NMHC in the polyvinyl fluoride (PVF) bags was less than 5% during a 7-hr storage period; significant NMHCs loss was detected in aluminum foil composite film and fluorinated ethylene propylene bags. The thermal desorption efficiency of NMHCs for adsorption tubes filled Carbopack B and Carboxen1000 sorbents was greater than 95% at 300℃, and the loss of NMHCs in the adsorption tubes during 20-days storage at 4℃ was less than 8%. The thermal desorption efficiency for C11 NMHCs in the adsorption tube filled with Carbograph 1 and Carbosieve SⅢ absorbents was less than 40% at 300℃, and pyrolysis of the absorbents at 330℃ interfered significantly with the measurements of some alkenes. The loss of alkenes was significant when NMHCs were sampled by cryo-enrichment at -90℃ in the presence of O3 for the online NMHC measurements, and negligible for enrichment using adsorption tubes at 25℃. Although O3 scrubbers have been widely used to eliminate the influence of O3 on NMHC measurements, the loss of NMHCs with carbon numbers greater than 8 was more than 10%. Therefore, PVF bags and adsorption tubes filled Carbopack B and Carboxen1000 sorbents were recommended for the sampling of atmospheric NMHCs.
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- 2022
6. Anaerobic oxidation of methane mediated by microbial extracellular respiration
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Xueqin Zhang, Zhiguo Yuan, and Shihu Hu
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chemistry.chemical_classification ,biology ,Chemistry ,Respiration ,Microorganism ,Electron acceptor ,biology.organism_classification ,Archaea ,Agricultural and Biological Sciences (miscellaneous) ,Selenate ,Electron transfer ,chemistry.chemical_compound ,Environmental chemistry ,Anaerobic oxidation of methane ,otorhinolaryngologic diseases ,Extracellular ,lipids (amino acids, peptides, and proteins) ,Anaerobiosis ,Sulfate ,Methane ,Oxidation-Reduction ,Ecology, Evolution, Behavior and Systematics - Abstract
Anaerobic oxidation of methane (AOM) can be microbially mediated by the reduction of different terminal electron acceptors. AOM coupled to reduction of sulfate, manganese/iron oxides, humic substances, selenate, arsenic and other artificial extracellular electron acceptors are recognized as processes associated with microbial extracellular respiration. In these processes, methane-oxidizing archaea transfer electrons to external electron acceptors or to interdependent microbial species, which are mechanistically dependent on versatile extracellular electron transfer (EET) pathways. This review compiles recent progress in the research of electromicrobiology of AOM based on the catalogue of different electron acceptors. Naturally distributed and artificially constructed EET-mediated AOM is summarized, with the discussion of their environmental importance and application potentials. The diversity of responsible microorganisms involved in EET-mediated AOM is discussed with both methane-oxidizing archaea and their putative bacterial partners. More importantly, the review highlights progress and deficiencies in our understanding of EET pathways in EET-mediated AOM, raising open research questions for future research.
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- 2021
7. Electrochemical iron production to enhance anaerobic membrane treatment of wastewater
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Zhetai Hu, Min Zheng, Shihu Hu, Pei-Ying Hong, Xueqing Zhang, Veljko Prodanovic, Kefeng Zhang, Ilje Pikaar, Liu Ye, Ana Deletic, and Zhiguo Yuan
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Environmental Engineering ,Sewage ,Caustics ,Ecological Modeling ,Iron ,Phosphorus ,Wastewater ,Sulfides ,Pollution ,Waste Disposal, Fluid ,Bioreactors ,Chlorides ,Biofuels ,Salts ,Anaerobiosis ,Hydrogen Sulfide ,Waste Management and Disposal ,Methane ,Water Science and Technology ,Civil and Structural Engineering - Abstract
Although iron salts such as iron(III) chloride (FeCl
- Published
- 2022
8. Methane dynamics in subtropical freshwater reservoirs and the mediating microbial communities
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Musenze, Ronald S., Fan, Lu, Grinham, Alistair, Werner, Ursula, Gale, Deborah, Udy, James, and Yuan, Zhiguo
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- 2016
- Full Text
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9. Role of VES-based fracturing fluid on gas sorption and diffusion of coal: An experimental study of Illinois basin coal
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Guofu Li, Bing Wu, Zhiguo Guo, Qiming Huang, Shimin Liu, and Gang Wang
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021110 strategic, defence & security studies ,Environmental Engineering ,Materials science ,Petroleum engineering ,Macropore ,Coalbed methane ,business.industry ,General Chemical Engineering ,Diffusion ,0211 other engineering and technologies ,Coal mining ,Sorption ,02 engineering and technology ,010501 environmental sciences ,Thermal diffusivity ,complex mixtures ,01 natural sciences ,Methane ,chemistry.chemical_compound ,chemistry ,Environmental Chemistry ,Coal ,Safety, Risk, Reliability and Quality ,business ,0105 earth and related environmental sciences - Abstract
As a kind of environmentally friendly and non-polluting fracturing fluid, the VES-based fracturing fluid is gradually promoted in the field coalbed methane (CBM) stimulation in recent year. However, the fracturing fluid residue trapped in the reservoir may have a potential negative impact on gas flow in CBM reservoirs. In this study, the fracturing fluid based on surfactant was selected to treat the coal sample. The lab experiments have been conducted including the isothermal methane sorption, the low-temperature nitrogen sorption and the 13C nuclear magnetic resonance (NMR) measurements. The results showed that the methane sorption capacity was modified with cleaning fluid treatment and residuals. It was found that the sorption capacity can be recovered through water washing. It is important to point out that the diffusivity of coal has been significantly damaged indicated by the paramount decrease of diffusion coefficient even after the water washing. Additionally, no significant chemical coal molecular structure changes were observed with VES-based fracturing fluid treatment based on the NMR data. The fracturing fluid changes the coal pore structure mainly because the residue of the fracturing fluid enters the coal pore system, thereby adhering on the pore wall or blocking the pore throat. Most residues entered into the coal seam will be trapped in mesopores and macropores, cause serious damage to the CBM diffusivity in the coal matrix, thereby posing an adverse effect to the CBM production.
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- 2021
10. Microbial Perchlorate Reduction Driven by Ethane and Propane
- Author
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Zhiguo Yuan, Jianhua Guo, Xuanyu Lu, Chun-Yu Lai, Mengxiong Wu, and Yulu Wang
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endocrine system ,Groundwater remediation ,Electron donor ,010501 environmental sciences ,Dechloromonas ,01 natural sciences ,Chloride ,Methane ,Polyhydroxyalkanoates ,Propane ,Perchlorate ,chemistry.chemical_compound ,Bioreactors ,RNA, Ribosomal, 16S ,medicine ,Environmental Chemistry ,0105 earth and related environmental sciences ,Ethane ,Perchlorates ,biology ,General Chemistry ,biology.organism_classification ,6. Clean water ,chemistry ,13. Climate action ,Environmental chemistry ,Oxidation-Reduction ,medicine.drug - Abstract
Previous studies demonstrated that methane can be used as an electron donor to microbially remove various oxidized contaminants in groundwater. Natural gas, which is more widely available and less expensive than purified methane, is potentially an alternative source of methane. However, natural gas commonly contains a considerable amount of ethane (C2H6) and propane (C3H8), in addition to methane. It is important that these gaseous alkanes are also utilized along with methane to avoid emissions. Here, we demonstrate that perchlorate (ClO4-), a frequently reported contaminant in groundwater, can be microbially reduced to chloride (Cl-) driven by C2H6 or C3H8 under oxygen-limiting conditions. Two independent membrane biofilm reactors (MBfRs) supplied with C2H6 and C3H8, respectively, were operated in parallel to biologically reduce ClO4-. The continuous ClO4- removal during long-term MBfR operation combined with the concurrent C2H6/C3H8 consumption and ClO4- reduction in batch tests confirms that ClO4- reduction was associated with C2H6 or C3H8 oxidation. Polyhydroxyalkanoates (PHAs) were synthesized in the presence of C2H6 or C3H8 and were subsequently utilized for supporting ClO4- bio-reduction in the absence of gaseous alkanes. Analysis by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) showed that transcript abundance of bmoX (encoding alpha hydroxylase subunit of C2H6/C3H8 monooxygenase) was positively correlated to the consumption rates of C2H6/C3H8, while pcrA (encoding a catalytic subunit of perchlorate reductase) was positively correlated to the consumption of ClO4-. High-throughput sequencing targeting 16S rRNA, bmoX, and pcrA indicated that Mycobacterium was the dominant microorganism oxidizing C2H6/C3H8, while Dechloromonas may be the major perchlorate-reducing bacterium in the biofilms. These findings shed light on microbial ClO4- reduction driven by C2H6 and C3H8, facilitating the development of cost-effective strategies for ex situ groundwater remediation.
- Published
- 2021
11. Roles and opportunities for microbial anaerobic oxidation of methane in natural and engineered systems
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Jianhua Guo, Zhiguo Yuan, Shihu Hu, Xueqin Zhang, Chun-Yu Lai, Joshua Frank, Esteban Marcellin, Chen Cai, Tao Liu, Mengxiong Wu, and Bingqing He
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Pollution ,Renewable Energy, Sustainability and the Environment ,Bioconversion ,Environmental remediation ,media_common.quotation_subject ,Global warming ,Methane ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,chemistry ,Environmental chemistry ,Anaerobic oxidation of methane ,Environmental Chemistry ,Environmental science ,Sink (computing) ,Energy source ,media_common - Abstract
Reduction in methane emissions to the Earth's atmosphere is a critical strategy for tackling climate change. It is well established that anaerobic oxidation of methane (AOM) associated with sulfate reduction functions as an important methane sink in marine sediments. However, recent findings show that AOM uses diverse electron acceptors across a range of habitats, prompting examination of the potential role of AOM in mitigation of methane emissions and global climate change in non-marine environments. Methane is also a valuable energy source, widely used for production of electricity. Recent studies suggest that AOM could be used to produce liquid fuels/chemicals. The potential involvement of CO2 in product formation is particularly exciting as methane bioconversion could act as a net sink of CO2. The discovery that AOM is able to transfer electrons to solid electron acceptors suggests that methane may be a suitable source of electrons for a bioelectrochemical, biosynthesis cell. In addition, AOM has been used for pollution control and environmental remediation, such as nitrogen removal from contaminated water. Herein, we review and discuss implications of the latest scientific discoveries in AOM for methane emissions from aquatic and terrestrial environments, and methane as a feedstock for various biotechnology platforms.
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- 2021
12. Anaerobic oxidation of propane coupled to nitrate reduction by a lineage within the class Symbiobacteriia
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Mengxiong Wu, Jie Li, Andy O. Leu, Dirk V. Erler, Terra Stark, Gene W. Tyson, Zhiguo Yuan, Simon J. McIlroy, and Jianhua Guo
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Ethane ,Multidisciplinary ,Nitrates ,Sulfates ,General Physics and Astronomy ,General Chemistry ,Carbon Dioxide ,General Biochemistry, Genetics and Molecular Biology ,Carbon ,Propane ,Fumarates ,Alkanes ,Ammonium Compounds ,Butanes ,Anaerobiosis ,Methane ,Oxidation-Reduction ,Ecosystem - Abstract
Anaerobic microorganisms are thought to play a critical role in regulating the flux of short-chain gaseous alkanes (SCGAs; including ethane, propane and butane) from terrestrial and aquatic ecosystems to the atmosphere. Sulfate has been confirmed to act as electron acceptor supporting microbial anaerobic oxidation of SCGAs, yet several other energetically more favourable acceptors co-exist with these gases in anaerobic environments. Here, we show that a bioreactor seeded with biomass from a wastewater treatment facility can perform anaerobic propane oxidation coupled to nitrate reduction to dinitrogen gas and ammonium. The bioreactor was operated for more than 1000 days, and we used 13C- and 15N-labelling experiments, metagenomic, metatranscriptomic, metaproteomic and metabolite analyses to characterize the microbial community and the metabolic processes. The data collectively suggest that a species representing a novel order within the bacterial class Symbiobacteriia is responsible for the observed nitrate-dependent propane oxidation. The closed genome of this organism, which we designate as ‘Candidatus Alkanivorans nitratireducens’, encodes pathways for oxidation of propane to CO2 via fumarate addition, and for nitrate reduction, with all the key genes expressed during nitrate-dependent propane oxidation. Our results suggest that nitrate is a relevant electron sink for SCGA oxidation in anaerobic environments, constituting a new microbially-mediated link between the carbon and nitrogen cycles.
- Published
- 2022
13. Simultaneous Removal of Dissolved Methane and Nitrogen from Synthetic Mainstream Anaerobic Effluent
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Shihu Hu, Jianhua Guo, Zhuan Khai Lim, Tao Liu, Hui Chen, Zhiguo Yuan, and Jie Li
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Denitrification ,Nitrogen ,010501 environmental sciences ,01 natural sciences ,7. Clean energy ,Methane ,12. Responsible consumption ,chemistry.chemical_compound ,Bioreactors ,RNA, Ribosomal, 16S ,Ammonium Compounds ,Bioreactor ,Environmental Chemistry ,Anaerobiosis ,Effluent ,0105 earth and related environmental sciences ,Chemistry ,General Chemistry ,Pulp and paper industry ,6. Clean water ,13. Climate action ,Anammox ,Anaerobic oxidation of methane ,Sewage treatment ,Aeration ,Oxidation-Reduction - Abstract
Anaerobic technologies have been proposed as a promising solution to enhance bioenergy recovery and to transform a wastewater treatment plant (WWTP) from an energy consumer to an energy exporter. However, 20-60% of the methane produced remains dissolved in the anaerobically treated effluent, which is a potent greenhouse gas and is easily stripped out in the aeration tank. This study aims to develop a solution using dissolved methane to support denitrification, thus simultaneously enhancing nitrogen removal and achieving beneficial use of dissolved methane. By coupling anaerobic ammonium oxidation (anammox) with nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO), up to 85% of dissolved methane and more than 99% of nitrogen were removed in parallel in a biofilm system. Mass balance was conducted during both long-term operation and short-term batch tests, which indicated that n-DAMO bacteria and n-DAMO archaea indeed contributed jointly to the methane removal. The 16S rRNA gene amplicon sequencing further showed the co-presence of n-DAMO bacteria and n-DAMO archaea, while anammox bacteria were detected with a low relative abundance. This proposed technology can potentially be applied to reduce the carbon footprint and to save the organic carbon consumption in WWTPs.
- Published
- 2020
14. Temperature-Tolerated Mainstream Nitrogen Removal by Anammox and Nitrite/Nitrate-Dependent Anaerobic Methane Oxidation in a Membrane Biofilm Reactor
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Zhuan Khai Lim, Shihu Hu, Tao Liu, Zhiguo Yuan, Jianhua Guo, and Hui Chen
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Denitrification ,Hydraulic retention time ,Nitrogen ,chemistry.chemical_element ,010501 environmental sciences ,01 natural sciences ,chemistry.chemical_compound ,Bioreactors ,Nitrate ,RNA, Ribosomal, 16S ,Ammonium Compounds ,Environmental Chemistry ,Anaerobiosis ,Nitrite ,Nitrites ,0105 earth and related environmental sciences ,Temperature ,Biofilm ,General Chemistry ,6. Clean water ,chemistry ,Anammox ,Biofilms ,Environmental chemistry ,Anaerobic oxidation of methane ,Methane ,Oxidation-Reduction - Abstract
The mainstream anaerobic ammonium oxidation (anammox) process provides strong support to the on-going paradigm shift from energy-negative to energy-neutral in wastewater treatment plants. However, the low temperature (e.g., below 15 °C) represents one of the major challenges for mainstream anammox in practice. In this study, a stable nitrogen removal rate (0.13 kg m-3 day-1), together with a high-level effluent quality (
- Published
- 2020
15. Anaerobic methane oxidation coupled to manganese reduction by members of the Methanoperedenaceae
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Gordon Southam, Gene W. Tyson, Shihu Hu, Zhiguo Yuan, Andy O. Leu, Victoria J. Orphan, Simon Jon McIlroy, and Chen Cai
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Geologic Sediments ,Birnessite ,chemistry.chemical_element ,Manganese ,010501 environmental sciences ,01 natural sciences ,Microbiology ,Methane ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Bioreactors ,Bioreactor ,Anaerobiosis ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,0303 health sciences ,Nitrates ,biology ,Environmental microbiology ,Bacteria ,Electron acceptor ,Biogeochemistry ,Methanosarcinales ,biology.organism_classification ,Archaea ,Biodegradation, Environmental ,chemistry ,Environmental chemistry ,Anaerobic oxidation of methane ,Candidatus ,Oxidation-Reduction - Abstract
Anaerobic oxidation of methane (AOM) is a major biological process that reduces global methane emission to the atmosphere. Anaerobic methanotrophic archaea (ANME) mediate this process through the coupling of methane oxidation to different electron acceptors, or in concert with a syntrophic bacterial partner. Recently, ANME belonging to the archaeal family Methanoperedenaceae (formerly known as ANME-2d) were shown to be capable of AOM coupled to nitrate and iron reduction. Here, a freshwater sediment bioreactor fed with methane and Mn(IV) oxides (birnessite) resulted in a microbial community dominated by two novel members of the Methanoperedenaceae, with biochemical profiling of the system demonstrating Mn(IV)-dependent AOM. Genomic and transcriptomic analyses revealed the expression of key genes involved in methane oxidation and several shared multiheme c-type cytochromes (MHCs) that were differentially expressed, indicating the likely use of different extracellular electron transfer pathways. We propose the names “Candidatus Methanoperedens manganicus” and “Candidatus Methanoperedens manganireducens” for the two newly described Methanoperedenaceae species. This study demonstrates the ability of members of the Methanoperedenaceae to couple AOM to the reduction of Mn(IV) oxides, which suggests their potential role in linking methane and manganese cycling in the environment.
- Published
- 2020
16. Modelling of methane production and emissions
- Author
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Sharma, Keshab, Gutierrez, Oriol, Yuan, Zhiguo, Daelman, Matthijs R.J., van Loosdrecht, Mark C.M., Volcke, Eveline I.P., Ye, Liu, Porro, Jose, and Nopens, Ingmar
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Emission ,Activated sludge ,Oxidation ,Sewer ,Production ,Methane ,Model - Abstract
This chapter provides a review of the models available for estimating the production and emission of methane from wastewater collection and treatment systems. The details of a number of mechanistic models as well as the simplified empirical models have been summarized. Their limitations have been identified and general methods for calibration and validation have been presented.
- Published
- 2022
17. Methane and Nitrous Oxide Emissions from a Temperate Peatland under Simulated Enhanced Nitrogen Deposition
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Xue Meng, Zhiguo Zhu, Jing Xue, Chunguang Wang, and Xiaoxin Sun
- Subjects
methane ,nitrous oxide ,nitrogen addition ,peatland ,Xiaoxing’an mountains ,Renewable Energy, Sustainability and the Environment ,Geography, Planning and Development ,Building and Construction ,Management, Monitoring, Policy and Law - Abstract
Nitrogen (N) deposition has increased in recent years and is significantly affected by global change and human activities. Wetlands are atmospheric CH4 and N2O sources and may be affected by changes in N deposition. To reveal the effects of increased N deposition on peatland greenhouse gas exchange, we observed the CH4 and N2O emissions from controlled microcosms collected from a temperate peatland in the Xiaoxing’an mountains, Northeast China. We found that the moss biomass did not change, but the total herb biomass increased by 94% and 181% with 5 and 10-times-higher N deposition, respectively. However, there were no significant changes in CH4 emissions from the microcosms with N addition. The unchanged CH4 emissions were mainly caused by the opposite effect of increased nitrate and ammonium concentrations on soil CH4 production and the increased plant biomass on CH4 emission. We also found that the manipulated microcosms with 5 and 10-times-higher N deposition had 8 and 20-times-higher seasonal average N2O emissions than the control microcosms, respectively. The increased N2O emissions were mainly caused by short-term (≤7 d) pulse emissions after N addition. The pulse N2O emission peaks were up to 1879.7 and 3836.5 μg m−2 h−1 from the microcosms with 5 and 10-times-higher N deposition, respectively. Nitrate and ammonium concentrations increasing in the soil pore water were the reason for the N2O emissions enhanced by N addition. Our results indicate that the increase in N deposition had no effects on the CH4 emissions but increased the N2O emissions of the temperate peatland. Moreover, pulse emissions are very important for evaluating the effect of N addition on N2O emissions.
- Published
- 2023
18. Microporous Carbon Adsorbents Prepared by Activating Reagent-Free Pyrolysis for Upgrading Low-Quality Natural Gas
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Yiwen Yang, Chen Fuqiang, Qilong Ren, Zongbi Bao, Zhiguo Zhang, and Qiwei Yang
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Coalbed methane ,Renewable Energy, Sustainability and the Environment ,business.industry ,General Chemical Engineering ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Microporous material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Methane ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Biogas ,Natural gas ,Reagent ,Environmental Chemistry ,0210 nano-technology ,business ,Carbon ,Pyrolysis - Abstract
Separation of methane and nitrogen is an essential matter of concern in upgrading low-quality natural gases such as biogas, coalbed methane, shale gas, and so forth. However, similar weak polaritie...
- Published
- 2019
19. Photocatalytic Oxidation of Small Molecular Hydrocarbons over ZnO Nanostructures: The Difference between Methane and Ethylene and the Impact of Polar and Nonpolar Facets
- Author
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Xiaoyang Pan, Zhonghua Li, Muzaffar Ahmad Boda, and Zhiguo Yi
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Nanostructure ,Materials science ,Ethylene ,Renewable Energy, Sustainability and the Environment ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Methane ,0104 chemical sciences ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Photocatalysis ,Environmental Chemistry ,Polar ,0210 nano-technology - Abstract
The development of efficient photocatalysts to oxidize small molecular hydrocarbons under atmospheric conditions is of great significance. In our previous study, it was found that nanosized ZnO can...
- Published
- 2019
20. Polyhydroxyalkanoate-driven current generation via acetate by an anaerobic methanotrophic consortium
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Xueqin Zhang, Simon J. McIlroy, Igor Vassilev, Hesamoddin Rabiee, Manuel Plan, Chen Cai, Bernardino Virdis, Gene W. Tyson, Zhiguo Yuan, and Shihu Hu
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Geologic Sediments ,Environmental Engineering ,Bacteria ,Ecological Modeling ,Polyhydroxyalkanoates ,Acetates ,Pollution ,Archaea ,Carbon ,Anaerobiosis ,Waste Management and Disposal ,Methane ,Oxidation-Reduction ,Water Science and Technology ,Civil and Structural Engineering - Abstract
Highlights • A Methanoperedenceae-dominated methanotrophic consortium was able to respirate to electrodes. • PHB was identified as energy source for the extracellular respiration of the consortium. • Acetate was a likely intermediate from degradation of PHB and EPSs in the consortium. • Methanoperedenceae interacted with Geobacter in the consortia via the diffusion of acetate. Anaerobic oxidation of methane (AOM) is an important microbial process mitigating methane (CH4) emission from natural sediments. Anaerobic methanotrophic archaea (ANME) have been shown to mediate AOM coupled to the reduction of several compounds, either directly (i.e. nitrate, metal oxides) or in consortia with syntrophic bacterial partners (i.e. sulfate). However, the mechanisms underlying extracellular electron transfer (EET) between ANME and their bacterial partners or external electron acceptors are poorly understood. In this study, we investigated electron and carbon flow for an anaerobic methanotrophic consortium dominated by ‘Candidatus Methanoperedens nitroreducens’ in a CH4-fed microbial electrolysis cell (MEC). Acetate was identified as a likely intermediate for the methanotrophic consortium, which stimulated the growth of the known electroactive genus Geobacter. Electrochemical characterization, stoichiometric calculations of the system, along with stable isotope-based assays, revealed that acetate was not produced from CH4 directly. In the absence of CH4, current was still generated and the microbial community remained largely unchanged. A substantial portion of the generated current in the absence of CH4 was linked to the oxidation of the intracellular polyhydroxybutyrate (PHB) and the breakdown of extracellular polymeric substances (EPSs). The ability of ‘Ca. M. nitroreducens’ to use stored PHB as a carbon and energy source, and its ability to donate acetate as a diffusible electron carrier expands the known metabolic diversity of this lineage that likely underpins its success in natural systems.
- Published
- 2021
21. Methane and Nitrous Oxide Emissions from a Temperate Peatland under Simulated Enhanced Nitrogen Deposition.
- Author
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Meng, Xue, Zhu, Zhiguo, Xue, Jing, Wang, Chunguang, and Sun, Xiaoxin
- Abstract
Nitrogen (N) deposition has increased in recent years and is significantly affected by global change and human activities. Wetlands are atmospheric CH
4 and N2 O sources and may be affected by changes in N deposition. To reveal the effects of increased N deposition on peatland greenhouse gas exchange, we observed the CH4 and N2 O emissions from controlled microcosms collected from a temperate peatland in the Xiaoxing'an mountains, Northeast China. We found that the moss biomass did not change, but the total herb biomass increased by 94% and 181% with 5 and 10-times-higher N deposition, respectively. However, there were no significant changes in CH4 emissions from the microcosms with N addition. The unchanged CH4 emissions were mainly caused by the opposite effect of increased nitrate and ammonium concentrations on soil CH4 production and the increased plant biomass on CH4 emission. We also found that the manipulated microcosms with 5 and 10-times-higher N deposition had 8 and 20-times-higher seasonal average N2 O emissions than the control microcosms, respectively. The increased N2 O emissions were mainly caused by short-term (≤7 d) pulse emissions after N addition. The pulse N2 O emission peaks were up to 1879.7 and 3836.5 μg m−2 h−1 from the microcosms with 5 and 10-times-higher N deposition, respectively. Nitrate and ammonium concentrations increasing in the soil pore water were the reason for the N2 O emissions enhanced by N addition. Our results indicate that the increase in N deposition had no effects on the CH4 emissions but increased the N2 O emissions of the temperate peatland. Moreover, pulse emissions are very important for evaluating the effect of N addition on N2 O emissions. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
22. Ultraviolet photochemistry of ethane: implications for the atmospheric chemistry of the gas giants
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Qingming Li, Zhigang He, Christopher S. Hansen, Weiqing Zhang, Yao Chang, Xueming Yang, Kaijun Yuan, Yong Yu, Guorong Wu, Michael N. R. Ashfold, Matthew Bain, Zhiguo Zhang, Jiayue Yang, Zhichao Chen, and Rebecca A. Ingle
- Subjects
Materials science ,010304 chemical physics ,Gas giant ,General Chemistry ,Photochemistry ,medicine.disease_cause ,7. Clean energy ,01 natural sciences ,Methane ,Jupiter ,chemistry.chemical_compound ,Chemistry ,Acetylene ,chemistry ,13. Climate action ,Atmospheric chemistry ,0103 physical sciences ,medicine ,Ground state ,Spectroscopy ,010303 astronomy & astrophysics ,Ultraviolet - Abstract
Chemical processing in the stratospheres of the gas giants is driven by incident vacuum ultraviolet (VUV) light. Ethane is an important constituent in the atmospheres of the gas giants in our solar system. The present work describes translational spectroscopy studies of the VUV photochemistry of ethane using tuneable radiation in the wavelength range 112 ≤ λ ≤ 126 nm from a free electron laser and event-triggered, fast-framing, multi-mass imaging detection methods. Contributions from at least five primary photofragmentation pathways yielding CH2, CH3 and/or H atom products are demonstrated and interpreted in terms of unimolecular decay following rapid non-adiabatic coupling to the ground state potential energy surface. These data serve to highlight parallels with methane photochemistry and limitations in contemporary models of the photoinduced stratospheric chemistry of the gas giants. The work identifies additional photochemical reactions that require incorporation into next generation extraterrestrial atmospheric chemistry models which should help rationalise hitherto unexplained aspects of the atmospheric ethane/acetylene ratios revealed by the Cassini–Huygens fly-by of Jupiter., The vacuum ultraviolet photodissociation dynamics of ethane provide clues for modelling the atmospheric chemistry of the gas giants.
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- 2021
23. Microbial Methane Conversion to Short-Chain Fatty Acids Using Various Electron Acceptors in Membrane Biofilm Reactors
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Jing-Huan Luo, Hui Chen, Jianhua Guo, Zhiguo Yuan, and Shuai Liu
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chemistry.chemical_classification ,Membranes ,Bioconversion ,chemistry.chemical_element ,Electrons ,General Chemistry ,010501 environmental sciences ,Electron acceptor ,Fatty Acids, Volatile ,7. Clean energy ,01 natural sciences ,Oxygen ,Methane ,Carbon utilization ,chemistry.chemical_compound ,Bioreactors ,chemistry ,Nitrate ,Biofilms ,Environmental chemistry ,Bioreactor ,Environmental Chemistry ,Nitrite ,0105 earth and related environmental sciences - Abstract
Given our vast methane reserves and the forecasted shortage of crude oil in the not too distant future, the conversion of methane into value-added liquid chemicals or fuels would be beneficial. The generated chemicals or fuels could augment the petroleum-dominated chemical market, and also satisfy the increasing demand for transportation fuels. While methane bioconversion to liquid chemicals has just been reported recently, there is limited understanding of the process. This study aims to clarify the potential electron acceptors that could support the process. Here we operated four membrane biofilm reactors (MBfRs) fed with nitrate, nitrite, oxygen at a relatively low rate, and oxygen at a relatively high rate, respectively, to study if they can support methane bioconversion to short-chain fatty acids (SCFAs) and the associated microbiological features. All tested electron acceptors facilitated methane bioconversion to SCFAs (ranging from 1.1 to 36.7 mg acetate L-1 d-1, or 3.4 to 114.6 mg acetate d-1 m-2 of biofilm). The carbon efficiency was estimated to be 7.9 ± 1.4% to 148.5 ± 1.3%, with an efficiency higher than 100%, suggesting the assimilation of other carbon, very likely CO2, into the products. A low oxygen supply rate of 46.4 ± 2.3 mg O2 d-1 m-2 was found to be the most favorable among all the electron conditions provided according to the SCFAs production rate and also the carbon utilization efficiency. Microbial characterization revealed that completely different communities evolved in the respective reactors, suggesting diverse microbial pathways exist for methane bioconversion into value-added chemicals.
- Published
- 2019
24. Correlation of absorption spectrum properties of methane with coupling variables between temperature and concentration
- Author
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Yan Lv, Dong Li, Bin Yao, Zhiguo Wang, Duan Buyue, and Di Wang
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Polynomial regression ,Materials science ,Tunable diode laser absorption spectroscopy ,Absorption spectroscopy ,Analytical chemistry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Methane ,Electronic, Optical and Magnetic Materials ,010309 optics ,Absorbance ,chemistry.chemical_compound ,chemistry ,Approximation error ,0103 physical sciences ,Electrical and Electronic Engineering ,0210 nano-technology ,Intensity (heat transfer) ,Line (formation) - Abstract
When using tunable diode laser absorption spectroscopy to detect methane on-line, the line intensity of methane absorption spectrum is affected by the change of ambient temperature, which has inevitable impacts on measurement results. Based on the direct absorption spectroscopy method, the absorption spectrum properties of methane with different concentrations (1%–15%) and temperatures (290–350 K) were analyzed, and the correlation between temperature-concentration coupling variables and spectral absorbance of methane was obtained by polynomial regression and global linear fitting of shared parameters. The results show that the spectral absorbance A of methane increases with the rise of its concentration at the same temperature. At the same concentration, the ratio of total partition function rQ plays a dominant role in the process of methane absorption spectrum line intensity changing with temperature, and the linear decrease of rQ with the increase of temperature, which results in the methane line intensity decreasing when the temperature increases. When the methane concentration is in the range of 1%–15% and the ambient temperature is 290–350 K, the relative error between the inversion result of correlation and the simulation data of HITEMP spectrum platform is less than 1%.
- Published
- 2019
25. Increasing capacity of an anaerobic sludge digester through FNA pre-treatment of thickened waste activated sludge
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Zhiguo Yuan, Haoran Duan, Lei Liu, Damien J. Batstone, Liu Ye, and Liguo Zhang
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Pre treatment ,Environmental Engineering ,Hydraulic retention time ,0208 environmental biotechnology ,Nitrous Acid ,02 engineering and technology ,010501 environmental sciences ,Waste Disposal, Fluid ,01 natural sciences ,Bioreactors ,Animal science ,Hydrolysis kinetics ,Anaerobiosis ,Methane production ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Sewage ,Anaerobic sludge ,Chemistry ,Hydrolysis ,Ecological Modeling ,Pollution ,020801 environmental engineering ,Anaerobic digestion ,Activated sludge ,Methane ,Anaerobic exercise - Abstract
Free nitrous acid (FNA) pre-treatment has been previously demonstrated to be effective in enhancing methane production and volatile solids (VS) destruction in the anaerobic digestion of waste activated sludge for an equivalent hydraulic retention time (HRT). We hypothesise that, due to enhancement of hydrolysis kinetics, FNA pre-treatment will also allow reduction in the HRT while retaining performance. This would allow for improvement of capacity constrained digesters. Two anaerobic sludge digesters (control-experiment) were fed with the same thickened waste activated sludge (TWAS) from a full-scale plant for 6 months. With 24 h pre-treatment of TWAS at an FNA concentration of 6.1 mgN/L (NO2-N = 250 mg/L, pH = 5.0, T = 25 °C), the HRT for the experimental anaerobic digester was progressively reduced from 15 days to 12 days and then to 7.5 days. In comparison, the control reactor was operated at a constant HRT of 15 days, representing typical loading conditions. With the shortened HRTs, the experimental AD reactor achieved VS destruction at 36.9 ± 0.8% (12 days) and 36.8 ± 1.0% (7.5 days), representing 30–40% relative increase in comparison to the control reactor (at 26.5 ± 0.8% and 28.3 ± 0.7%, respectively, in the same two periods). This was supported by a similar (31–35%) increase in the methane production per unit of VS fed. The volumetric methane production rate of the experimental digester was increased by 165% at HRT of 7.5 days compared with the control digester at HRT of 15 days. The results demonstrated that FNA pre-treatment of TWAS can substantially increase the capacity of an anaerobic sludge digester, with a highly favourable economic outcome.
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- 2019
26. Experimental characterizing combustion emissions and thermodynamic properties of a thermoacoustic swirl combustor
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Yong Chen, Zhiguo Zhang, Dan Zhao, Bing Wang, Guoneng Li, Yuze Sun, Shen Li, and Siliang Ni
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Flue gas ,Work (thermodynamics) ,Materials science ,020209 energy ,Mechanical Engineering ,Thermoacoustics ,02 engineering and technology ,Building and Construction ,Mechanics ,Management, Monitoring, Policy and Law ,Combustion ,Methane ,Volumetric flow rate ,chemistry.chemical_compound ,General Energy ,020401 chemical engineering ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Combustor ,0204 chemical engineering ,NOx - Abstract
Many practical lean-premixed combustion systems involved in land-based power plants, gas turbines and boilers are susceptible to self-excited combustion instability, which is characterized by detrimental periodic pressure oscillations. Little attention has been paid on experimentally characterizing the chemical emissions and thermodynamic properties of a thermoacoustic swirl combustor. In this work, the effects of (1) fuel-air equivalence ratio Φ and fuel flow rate QCH4 on generating such combustion instability and its impact on chemical emissions and thermodynamic properties in a swirling combustor are experimentally studied. For this, a methane-fueled lab-scale swirl combustor is designed and tested. To monitor the thermodynamic properties of the combustor, an acoustic pressure sensor, an infrared thermal imaging camera, K-type thermal couples, and an infrared flue gas analyzer are applied. It is found that the fuel-air ratio plays an important role on generating combustion instability at different frequencies and amplitudes. This is confirmed by conducting autocorrelation and frequency spectrum analyses of the acoustic pressure time trace. Furthermore, the dominant mode swap (mode-switching) between a low frequency ω1 and a high non-harmonic one is experimentally observed. Whether the mode switching from high (harmonic or non-harmonic) to low frequency or low to high frequency is found to depend strongly on QCH4. As the equivalence ratio is changed from lean to rich, i.e. 0.8 ≤ Φ ≤ 1.2, NOx emission is increased from 1 ppm to 37 ppm. However, CO emission is decreased by 2 order of magnitudes from 1000 ppm first and then increased. The minimum CO emission is approximately 3.0 ppm. In addition, O2 concentration is decreased by more than 80% with increased Φ, depending on the methane flow rate. This means that the combustion efficiency characterized by the O2 emission is decreased dramatically from 99.5% to 68% with Φ increased from 0.6 to 1.2. The present work sheds light on the characteristics of chemical emissions and thermodynamic properties, when a thermoacoustic swirl combustor is operated with methane-air equivalence ratio Φ varied from lean to rich condition and different QCH4. It opens up a practical means to design a stably operated but low-emission thermoacoustic swirl combustor.
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- 2019
27. Photocatalytic oxidation of methane over CuO-decorated ZnO nanocatalysts
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Xiaoyang Pan, Zhiguo Yi, and Zhonghua Li
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Materials science ,Nanocomposite ,Renewable Energy, Sustainability and the Environment ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Methane ,Nanomaterial-based catalyst ,Catalysis ,chemistry.chemical_compound ,Catalytic oxidation ,chemistry ,Chemical engineering ,Anaerobic oxidation of methane ,Photocatalysis ,General Materials Science ,Fourier transform infrared spectroscopy ,0210 nano-technology - Abstract
Catalytic oxidation of methane under mild conditions remains a challenge in the industrial catalytic processes. Herein, we report a highly efficient CuO/ZnO nanocomposite photocatalyst for methane oxidation under ambient conditions. It was found that both the CH4 photooxidative activity and stability over ZnO are considerably improved by loading a tiny amount of CuO, though CuO itself exhibits no activity on methane oxidation. On the basis of the experimental results in conjunction with in situ electron paramagnetic resonance (EPR) and Fourier transform infrared spectroscopy (FTIR) studies, the photocatalytic reaction process of CH4 over CuO/ZnO composite microstructures is comprehensively discussed.
- Published
- 2019
28. Enhancing anaerobic digestion using free nitrous acid: Identifying the optimal pre-treatment condition in continuous operation
- Author
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Zhiguo Yuan, Wenbo Yu, Zhiyao Wang, Yijing Li, Shihu Hu, Carlos Ernando da Silva, Angelica Guerrero Calderon, Ziping Wu, Haoran Duan, Xiaoguang Chen, Zhongwei Chen, Sohan Shrestha, and Jurg Keller
- Subjects
Pre treatment ,Environmental Engineering ,Continuous operation ,Nitrous Acid ,Waste Disposal, Fluid ,chemistry.chemical_compound ,Bioreactors ,Anaerobiosis ,Technology implementation ,Nitrite ,skin and connective tissue diseases ,Waste Management and Disposal ,Water Science and Technology ,Civil and Structural Engineering ,Nitrous acid ,Sewage ,Chemistry ,Ecological Modeling ,Thermal hydrolysis ,Pulp and paper industry ,Pollution ,body regions ,Anaerobic digestion ,surgical procedures, operative ,Activated sludge ,Methane - Abstract
Free Nitrous Acid (FNA) pre-treatment is a promising technology demonstrated effective in improving waste activated sludge degradability and anaerobic digestion (AD) performance. Pre-treatment conditions including FNA concentration and treatment duration determine operational and capital cost of full-scale implementation, which have not been studied in long-term experiments. The knowledge of FNA pre-treatment conditions improving the AD performance is urgently required to determine suitable conditions for the technology implementation. In this work, five different FNA concentrations (2.2, 4.4, 7.2, 12 mgN/L and nitrite only without pH adjustment) and three treatment durations (8, 24 and 48 h) were studied in four lab-scale semi-continuous AD reactors for over 300 days. FNA pre-treatment was shown under all tested conditions effective in enhancing AD performances, while its effectiveness and resulted benefits varied substantially amongst different pre-treatment conditions. The long-term experiment demonstrated that the methane production, sludge reduction and digested sludge viscosity of AD are positively correlated with the FNA concentration and durations, until an optimal condition is reached, which was identified in this work to be FNA concentration of 7.2 mgN/L and treatment duration of 24 h. Microbial community changes supported the apparent observation of enhanced sludge degradation at elevating FNA concentrations applied during pre-treatment. The short-term sludge solubilization results were inconsistent with the long-term AD performance, which was potentially caused by inhibitions from stringent FNA pre-treatment conditions applied (FNA = 12 mgN/L with 24-hour treatment & FNA = 7.2 mgN/L with 48-hour treatment). Overall, results suggested FNA pre-treatment at the optimized condition is highly beneficial to WWTPs and competitive with other pre-treatment technologies, e.g., thermal hydrolysis pre-treatment. This work comprehensively evaluated the key design parameters of FNA pre-treatment process, reached a major milestone in the development and applications of FNA technologies.
- Published
- 2021
29. Anaerobic Oxidation of Methane Coupled with Dissimilatory Nitrate Reduction to Ammonium Fuels Anaerobic Ammonium Oxidation
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Defeng Xing, Guo-Jun Xie, Bing-Feng Liu, Lu Yang, Xin Tan, Lai Peng, Nanqi Ren, Wen-Bo Nie, Jie Ding, and Zhiguo Yuan
- Subjects
Denitrification ,010501 environmental sciences ,01 natural sciences ,Methane ,chemistry.chemical_compound ,Bioreactors ,Nitrate ,Ammonium Compounds ,Environmental Chemistry ,Ammonium ,Anaerobiosis ,Nitrite ,Nitrogen cycle ,Ecosystem ,Nitrites ,0105 earth and related environmental sciences ,Nitrates ,Chemistry ,General Chemistry ,13. Climate action ,Anammox ,Environmental chemistry ,Anaerobic oxidation of methane ,Oxidation-Reduction - Abstract
Nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) is critical for mitigating methane emission and returning reactive nitrogen to the atmosphere. The genomes of n-DAMO archaea show that they have the potential to couple anaerobic oxidation of methane to dissimilatory nitrate reduction to ammonium (DNRA). However, physiological details of DNRA for n-DAMO archaea were not reported yet. This work demonstrated n-DAMO archaea coupling the anaerobic oxidation of methane to DNRA, which fueled Anammox in a methane-fed membrane biofilm reactor with nitrate as only electron acceptor. Microelectrode analysis revealed that ammonium accumulated where nitrite built up in the biofilm. Ammonium production and significant upregulation of gene expression for DNRA were detected in suspended n-DAMO culture with nitrite exposure, indicating that nitrite triggered DNRA by n-DAMO archaea. 15N-labeling batch experiments revealed that n-DAMO archaea produced ammonium from nitrate rather than from external nitrite. Localized gradients of nitrite produced by n-DAMO archaea in biofilms induced ammonium production via the DNRA process, which promoted nitrite consumption by Anammox bacteria and in turn helped n-DAMO archaea resist stress from nitrite. As biofilms predominate in various ecosystems, anaerobic oxidation of methane coupled with DNRA could be an important link between the global carbon and nitrogen cycles that should be investigated in future research.
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- 2020
30. Copper stimulation on methane-supported perchlorate reduction in a membrane biofilm reactor
- Author
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Shihu Hu, Yulu Wang, Jianhua Guo, Xuanyu Lu, Chun-Yu Lai, Mengxiong Wu, and Zhiguo Yuan
- Subjects
Environmental Engineering ,Methane monooxygenase ,Health, Toxicology and Mutagenesis ,chemistry.chemical_element ,Dechloromonas ,03 medical and health sciences ,Perchlorate ,chemistry.chemical_compound ,Bioreactors ,RNA, Ribosomal, 16S ,Environmental Chemistry ,Azospira ,Waste Management and Disposal ,030304 developmental biology ,0303 health sciences ,Perchlorates ,biology ,030306 microbiology ,biology.organism_classification ,Pollution ,Copper ,Methylomonas ,chemistry ,Biofilms ,Anaerobic oxidation of methane ,Methylocystaceae ,Oxygenases ,biology.protein ,Methane ,Oxidation-Reduction ,Nuclear chemistry - Abstract
The present study demonstrated that the perchlorate reduction rate in a methane-based membrane biofilm reactor was significantly enhanced from 14.4 to 25.6 mg-Cl/L/d by increasing copper concentration in the feeding medium from 1 to 10 μM, indicating a stimulatory effect of copper on the methane-supported perchlorate reduction process. Batch tests further confirmed that the increased copper concentration enhanced both methane oxidation and perchlorate reduction rates, which was supported by an increasing trend of functional genes (pmoA for methanotrophs and pcrA for specific perchlorate reducers) abundances through quantitative polymerase chain reaction (qPCR). Both 16S rRNA gene sequencing and functional genes (pmoA and pcrA) sequencing jointly revealed that the biofilm supplied with a higher copper concentration exhibited a more diverse microbial community. The methane-supported perchlorate reduction was accomplished through a synergistic association of methanotrophs (Methylocystis, Methylomonas, and Methylocystaceae) and perchlorate reducers (Dechloromonas, Azospira, Magnetospirillum, and Denitratisoma). Acetate may function as the key syntrophic linkage between methanotrophs and perchlorate reducers. It was proposed that the increased copper concentration improved the activity of particulate methane monooxygenase (pMMO) for methane oxidation or promoted the biosynthesis of intracellular carbon storage compounds polyhydroxybutyrate (PHB) in methanotrophs for generating more acetate available for perchlorate reduction.
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- 2022
31. Rapid formation of granules coupling n-DAMO and anammox microorganisms to remove nitrogen
- Author
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Shihu Hu, Xiaoying Zheng, Chunshuang Liu, Zhiguo Yuan, Hui Chen, Jianhua Guo, Jia Meng, and Tao Liu
- Subjects
Environmental Engineering ,Nitrogen ,Microorganism ,0208 environmental biotechnology ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Granulation ,Bioreactors ,RNA, Ribosomal, 16S ,Ammonium Compounds ,Anaerobiosis ,Waste Management and Disposal ,In Situ Hybridization, Fluorescence ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Nitrates ,biology ,Chemistry ,Ecological Modeling ,Granule (cell biology) ,biology.organism_classification ,Pollution ,020801 environmental engineering ,Wastewater ,Anammox ,Environmental chemistry ,Anaerobic oxidation of methane ,Denitrification ,Methane ,Oxidation-Reduction ,Bacteria ,Archaea - Abstract
Granular sludge exhibits unique features, including rapid settling velocity, high loading rate and relative insensitivity against inhibitors, thus being a favorable platform for the cultivation of slow-growing and vulnerable microorganisms, such as anaerobic ammonium oxidation (anammox) bacteria and nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) microorganisms. While anammox granules have been widely applied, little is known about how to speed up the granulation process of n-DAMO microorganisms, which grow even slower than anammox bacteria. In this study, we used mature anammox granules as biotic carriers to embed n-DAMO microorganisms, which obtained combined anammox + n-DAMO granules within 6 months. The results of whole-granule 16S rRNA gene amplicon sequencing showed the coexistence of anammox bacteria, n-DAMO bacteria and n-DAMO archaea. The microbial stratification along granule radius was further elucidated by cryosection-16S rRNA gene amplicon sequencing, showing the dominance of n-DAMO archaea and anammox bacteria at inner and outer layers, respectively. Moreover, the images of cryosection-fluorescence in situ hybridization (FISH) verified this stratification and also indicated a shift in microbial stratification. Specifically, n-DAMO bacteria and n-DAMO archaea attached to the anammox granule surface initially, which moved to the inner layer after 4-months operation. On the basis of combined anammox + n-DAMO granules, a practically useful nitrogen removal rate (1.0 kg N/m3/d) was obtained from sidestream wastewater, which provides new avenue to remove nitrogen from wastewater using methane as carbon source.
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- 2020
32. Control sulfide and methane production in sewers based on free ammonia inactivation
- Author
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Xia Huang, Yanchen Liu, Zhiqiang Zuo, He Li, Zhiguo Yuan, Min Zheng, Yarong Song, Daheng Ren, and Ying Gao
- Subjects
010504 meteorology & atmospheric sciences ,Sulfide ,Hydrogen sulfide ,Sewage ,Urine wastewater ,010501 environmental sciences ,Sulfides ,01 natural sciences ,Methane ,Corrosion ,chemistry.chemical_compound ,Ammonia ,Sanitary sewer ,lcsh:Environmental sciences ,0105 earth and related environmental sciences ,General Environmental Science ,chemistry.chemical_classification ,Free ammonia ,lcsh:GE1-350 ,business.industry ,Sulfates ,Sewer biofilm ,Sulfide and methane control ,chemistry ,Wastewater ,Biocidal effect ,Environmental chemistry ,Environmental science ,business - Abstract
Emissions of hydrogen sulfide and methane are two of the major concerns in sewers, causing corrosion, odour and health problems. This study proposed a new free ammonia (FA)-based approach for controlling the biological production of sulfide and methane in sewers. This is based on the discovery that the FA contained in urine wastewater is strongly biocidal to anaerobic sewer biofilms. Long-term operation of two laboratory sewer reactors, with one being dosed with urine wastewater and the other being dosed with raw sewage as a control, revealed the effectiveness of the proposed FA approach. The results showed that dosing of real urine wastewater at FA concentration of 154 mg NH3-N/L with exposure for 24 h immediately reduced over 80% sulfide and methane in the experimental sewer reactor, while the time for recovering 50% sulfide and methane production were 6 days and 28 days, respectively. It also showed that intermittent dosing with an interval time of 5–15 days reduced around 60% sulfide on average. As suggested by community analysis, the remaining sulfide might be produced by a sulfate-reducing bacterial genus Desulfobulbus. Collectively, urine is a part of municipal sewage, and thus separation and re-dosing of the urine wastewater into the sewer for sulfide and methane control should enable the minimization of operational costs and environmental impacts, compared with the previous dosing of chemicals.
- Published
- 2020
33. Enhancing methane oxidation in a bioelectrochemical membrane reactor using a soluble electron mediator
- Author
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Zhiguo Yuan, Joshua Frank, Bernardino Virdis, Hesamoddin Rabiee, Xueqin Zhang, Shihu Hu, Chen Cai, and Terra Stark
- Subjects
Bioelectrochemical membrane reactor ,lcsh:Biotechnology ,Kinetics ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,Electrochemistry ,7. Clean energy ,01 natural sciences ,Applied Microbiology and Biotechnology ,lcsh:Fuel ,Methane ,03 medical and health sciences ,Electron transfer ,chemistry.chemical_compound ,lcsh:TP315-360 ,lcsh:TP248.13-248.65 ,030304 developmental biology ,0105 earth and related environmental sciences ,0303 health sciences ,Membrane reactor ,Renewable Energy, Sustainability and the Environment ,Chemistry ,Redox mediator ,Research ,Ferricyanide ,General Energy ,Membrane ,Chemical engineering ,13. Climate action ,Anaerobic oxidation of methane ,Bioelectrochemical methane oxidation ,ANME ,Biotechnology - Abstract
Background Bioelectrochemical methane oxidation catalysed by anaerobic methanotrophic archaea (ANME) is constrained by limited methane bioavailability as well as by slow kinetics of extracellular electron transfer (EET) of ANME. In this study, we tested a combination of two strategies to improve the performance of methane-driven bioelectrochemical systems that includes (1) the use of hollow fibre membranes (HFMs) for efficient methane delivery to the ANME organisms and (2) the amendment of ferricyanide, an effective soluble redox mediator, to the liquid medium to enable electrochemical bridging between the ANME organisms and the anode, as well as to promote EET kinetics of ANME. Results The combined use of HFMs and the soluble mediator increased the performance of ANME-based bioelectrochemical methane oxidation, enabling the delivery of up to 196 mA m−2, thereby outperforming the control system by 244 times when HFMs were pressurized at 1.6 bar. Conclusions Improving methane delivery and EET are critical to enhance the performance of bioelectrochemical methane oxidation. This work demonstrates that by process engineering optimization, energy recovery from methane through its direct oxidation at relevant rates is feasible.
- Published
- 2020
34. NOx Emissions and Nitrogen Fate at High Temperatures in Staged Combustion
- Author
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Su Xiaohui, Defu Che, Wu Song, and Wang Zhiguo
- Subjects
Control and Optimization ,Materials science ,020209 energy ,Analytical chemistry ,strong reducing atmosphere ,Energy Engineering and Power Technology ,chemistry.chemical_element ,CHEMKIN ,02 engineering and technology ,Combustion ,lcsh:Technology ,Methane ,high temperature ,chemistry.chemical_compound ,020401 chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,Tube furnace ,0204 chemical engineering ,Electrical and Electronic Engineering ,Engineering (miscellaneous) ,Staged combustion ,NOx ,Renewable Energy, Sustainability and the Environment ,lcsh:T ,Reducing atmosphere ,NOx emission ,Nitrogen ,staged combustion ,chemistry ,chemical simulation ,Energy (miscellaneous) - Abstract
Staged combustion is an effective technology to control NOx emissions for coal-fired boilers. In this paper, the characteristics of NOx emissions under a high temperature and strong reducing atmosphere conditions in staged air and O2/CO2 combustion were investigated by CHEMKIN. A methane flame doped with ammonia and hydrogen cyanide in a tandem-type tube furnace was simulated to detect the effects of combustion temperature and stoichiometric ratio on NOx emissions. Mechanism analysis was performed to identify the elementary steps for NOx formation and reduction at high temperatures. The results indicate that in both air and O2/CO2 staged combustion, the conversion ratios of fuel-N to NOx at the main combustion zone exit increase as the stoichiometric ratio rises, and they are slightly affected by the combustion temperature. The conversion ratios at the burnout zone exit decrease with the increasing stoichiometric ratio at low temperatures, and they are much higher than those at the main combustion zone exit. A lot of nitrogen compounds remain in the exhaust of the main combustion zone and are oxidized to NOx after the injection of a secondary gas. Staged combustion can lower NOx emissions remarkably, especially under a high temperature (&ge, 1600 °, C) and strong reducing atmosphere (SR &le, 0.8) conditions. Increasing the combustion temperature under strong reducing atmosphere conditions can raise the H atom concentration and change the radical pool composition and size, which facilitate the reduction of NO to N2. Ultimately, the increased OH/H ratio in staged O2/CO2 combustion offsets part of the reducibility, resulting in the final NOx emissions being higher than those in air combustion under the same conditions.
- Published
- 2020
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35. Biogas-driven complete nitrogen removal from wastewater generated in side-stream partial nitritation
- Author
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Hui Chen, Jianhua Guo, Zhiguo Yuan, Zhuan Khai Lim, Tao Liu, Zhiyao Wang, and Shihu Hu
- Subjects
Environmental Engineering ,010504 meteorology & atmospheric sciences ,Nitrogen ,chemistry.chemical_element ,010501 environmental sciences ,Wastewater ,01 natural sciences ,7. Clean energy ,Waste Disposal, Fluid ,Methane ,chemistry.chemical_compound ,Bioreactors ,Biogas ,Rivers ,RNA, Ribosomal, 16S ,Ammonium Compounds ,Environmental Chemistry ,Anaerobiosis ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Pulp and paper industry ,Pollution ,6. Clean water ,Anaerobic digestion ,chemistry ,Anammox ,Biofuels ,Anaerobic oxidation of methane ,Denitrification ,Sewage treatment ,Oxidation-Reduction - Abstract
Anaerobic digestion is an attractive process in wastewater treatment plants (WWTPs) to achieve simultaneous sludge reduction and energy recovery. While converting the majority of organic carbon to biogas (mainly consisting 60%CH4 + 40%CO2), the high-strength anaerobic digestion liquor consists of a high level of nitrogen concentration. The feasibility of utilizing biogas produced in-situ to achieve satisfactory nitrogen removal performance from partially nitrified anaerobic digestion liquor was examined in this study. To this end, a membrane biofilm reactor (MBfR) was used to couple nitrite- or nitrate-dependent anaerobic methane oxidation (n-DAMO) and anammox microorganisms, which was supplied with synthetic biogas and partially nitrified anaerobic digestion liquor (470 mg NH4+-N/L + 560 mg NO2−-N/L). The MBfR achieved not only nearly complete nitrogen removal (~99%), but also a practically useful nitrogen removal rate above 1 kg N/m3/d. Due to the acidification caused by excessive CO2 supply from biogas, pH dropping was observed. Two corresponding strategies, i.e., intermittent alkali dosing and intermittent nitrogen gas flushing, were developed to control the pH at neutral. Mass balance based on batch tests and microbial community analysis by 16S rRNA gene amplicon sequencing both showed the joint contribution of anammox bacteria and anaerobic methane oxidizers to the nitrogen removal. This study proved the potential and capacity of MBfR to access complete nitrogen removal from high-strength wastewater by using biogas produced in-situ, thus leading to a significant reduction of external carbon addition in practice.
- Published
- 2020
36. Model-based investigation of membrane biofilm reactors coupling anammox with nitrite/nitrate-dependent anaerobic methane oxidation
- Author
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Zhiguo Yuan, Jianhua Guo, Tao Liu, and Shihu Hu
- Subjects
010504 meteorology & atmospheric sciences ,Nitrogen ,010501 environmental sciences ,7. Clean energy ,01 natural sciences ,Methane ,12. Responsible consumption ,chemistry.chemical_compound ,Bioreactors ,Nitrate ,Ammonium ,Anaerobiosis ,Nitrite ,Nitrites ,lcsh:Environmental sciences ,0105 earth and related environmental sciences ,General Environmental Science ,lcsh:GE1-350 ,6. Clean water ,Anaerobic digestion ,chemistry ,Wastewater ,13. Climate action ,Anammox ,Environmental chemistry ,Biofilms ,Anaerobic oxidation of methane ,Denitrification ,Oxidation-Reduction - Abstract
An innovative process coupling anaerobic ammonium oxidation (anammox) with nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) in membrane biofilm reactors (MBfRs) has been developed to achieve high-level nitrogen removal from both sidestream (i.e., anaerobic digestion liquor) and mainstream (i.e., domestic strength) wastewater. In this study, a 1D biofilm model embedding the n-DAMO and anammox reactions was developed to facilitate further understanding of the process and its optimization. The model was calibrated and validated using comprehensive data sets from two independent MBfRs, treating sidestream- and mainstream-strength wastewater, respectively. Modelling results revealed a unique biofilm stratification. While anammox bacteria dominated throughout the biofilm, n-DAMO archaea (coupling nitrate reduction with anaerobic methane oxidation) only occurred at the inner layer and n-DAMO bacteria (coupling nitrite reduction with anaerobic methane oxidation) spread more evenly with a slightly higher fraction in the outer layer. The established MBfRs were robust against dynamic influent flowrates and nitrite/ammonium ratios. Thicker biofilms were beneficial for not only the total nitrogen (TN) removal but also the system robustness. Additionally, a positive correlation between the nitrogen removal efficiency and the residual methane emission was observed, as a result of higher methane partial pressure required. However, there was a threshold of methane partial pressure, above which the residual methane increased but nitrogen removal efficiency was stable. Meanwhile, thicker biofilms were also favorable to achieve less residual methane emission. Simulation results also suggested the feasibility of methane-based MBfRs to polish mainstream anammox effluent to meet a stringent N discharge standard (e.g., TN
- Published
- 2020
37. Experimental and simulation investigations of the impact of polyacrylamide on CBM ad-/desorption
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Gang Wang, Bing Wu, Yu Liu, Qiming Huang, Lulu Sun, and Zhiguo Guo
- Subjects
Materials science ,business.industry ,Polyacrylamide ,technology, industry, and agriculture ,Sorption ,engineering.material ,Geotechnical Engineering and Engineering Geology ,complex mixtures ,Isothermal process ,Methane ,chemistry.chemical_compound ,Fuel Technology ,Coating ,chemistry ,Chemical engineering ,Desorption ,engineering ,Coal ,business ,Porosity - Abstract
Slickwater is commonly used during hydraulic fracturing in coalbed gas well, which is often prepared with polyacrylamide as the friction reducer. To investigate the impact of polyacrylamide on CBM ad-/desorption after a fracturing operation, slickwater with different concentrations of polyacrylamide were prepared and used to treat Illinois coal samples. Both isothermal ad-/desorption experiments and molecular simulations were conducted to investigate the impact of slickwater. Nuclear magnetic resonance measurements were performed to analyse the evolution of surface functional groups of coal during slickwater treatment. The results show that there is no significant chemical reaction between the coal component and polyacrylamide. Because of the porosity of the polyacrylamide coating adhered onto the surface of the pore, polyacrylamide has a significant sorption capacity of methane. The methane sorption amount of the ‘coal-slickwater’ system is higher than that of raw coal. However, with the increase of the amount of residue entering the pores, the porous structure of the polyacrylamide coating becomes denser, blocking some pores and the pore surface area is reduced; thus, the overall sorption capacity of the ‘coal-polyacrylamide’ system decreases.
- Published
- 2022
38. A robust two–dimensional layered metal–organic framework for efficient separation of methane from nitrogen
- Author
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Yiwen Yang, Rundao Chen, Qilong Ren, Baogen Su, Lihang Chen, Fang Zheng, Zongbi Bao, Zhiguo Zhang, and Qiwei Yang
- Subjects
Materials science ,business.industry ,Filtration and Separation ,Methane ,Analytical Chemistry ,Ion ,chemistry.chemical_compound ,Tight binding ,Adsorption ,chemistry ,Chemical engineering ,Natural gas ,Molecule ,Metal-organic framework ,business ,Selectivity - Abstract
Selective capture and separation of methane (CH4) from nitrogen (N2) is a feasible approach to mitigate the effects of global warming and to improve the heating value of low-quality natural gas. However, the efficient separation of CH4/N2 is a challenge issue since their very close kinetic diameters and thermodynamic properties. In this work, a new type of two-dimensional (2D) layered metal–organic framework (MOF) with permanent rhomboid pore channels, denoted as Ni(4-DPDS)2CrO4, (4-DPDS = 4,4′-dipyridyldisulfide) was synthesized for the first time and used for CH4/N2 separation. This novel 2D MOF not only performs high stability as outstanding as or even better than previously reported 3D MOFs but also exhibits a relatively high CH4 adsorption capacity of 0.95 mmol/g. Ni(4-DPDS)2CrO4 has a high affinity towards CH4 with the highest reported Qst value of 28.4 kJ/mol as well as a high CH4/N2 selectivity of 7.3, which is comparable to the state-of-the-art MOF materials reported so far. DFT calculations revealed the energy favorable binding sites for methane molecules are located in the middle of the cavity decorated with CrO42- anion. Such an angular inorganic anion provides polar sites and makes guest–host interactions in close proximity, affording tight binding affinity. Breakthrough experiments and regenerability tests suggest it is a promising material in natural gas purification.
- Published
- 2022
39. High-Rate Production of Short-Chain Fatty Acids from Methane in a Mixed-Culture Membrane Biofilm Reactor
- Author
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Jianhua Guo, Zhiguo Yuan, Lei Zhao, Shihu Hu, and Hui Chen
- Subjects
0301 basic medicine ,Methanobacterium ,Ecology ,biology ,Bioconversion ,Health, Toxicology and Mutagenesis ,Microorganism ,030106 microbiology ,Biofilm ,Methanosarcina ,biology.organism_classification ,7. Clean energy ,Pollution ,6. Clean water ,Methane ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Membrane ,chemistry ,Environmental Chemistry ,Food science ,Sporolactobacillus ,Waste Management and Disposal ,Water Science and Technology - Abstract
The bioconversion of methane to liquid chemicals has attracted much attention. However, the production rate reported to date has been far lower than what is required for economical viability. This is partly due to the low solubility of methane, the low mass transfer rate, and low microbial activities. This study demonstrates a production rate of close to 10 g of short-chain fatty acids (SCFAs) per liter per day with a mixed-culture biofilm growing in a membrane biofilm reactor (MBfR). Hollow fiber membranes were used both to deliver a high flux of methane and to provide a surface on which slow-growing microorganisms could form biofilms with intensified activities. The rate achieved is nearly 2 orders of magnitude higher than the highest SCFA production rate reported to date and is close to the rates required for practical applications (∼12–120 g L–1 day–1). The consortium in the biofilm was dominated by methanogens Methanosarcina and Methanobacterium and acid-producing bacteria Sporolactobacillus and Prop...
- Published
- 2018
40. Optimization of free nitrous acid pre-treatment on waste activated sludge
- Author
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Maycoll Stiven Romero-Güiza, Maite Pijuan, P. Icaran, S. Zahedi, and Zhiguo Yuan
- Subjects
Pre treatment ,Environmental Engineering ,0208 environmental biotechnology ,Nitrous Acid ,Bioengineering ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,chemistry.chemical_compound ,Bioreactors ,Anaerobiosis ,Methane production ,Nitrite ,Neutral ph ,Waste Management and Disposal ,Nitrites ,0105 earth and related environmental sciences ,Nitrous acid ,Sewage ,Renewable Energy, Sustainability and the Environment ,General Medicine ,Hydrogen-Ion Concentration ,020801 environmental engineering ,Anaerobic digestion ,Activated sludge ,chemistry ,Sewage sludge treatment ,Methane ,Nuclear chemistry - Abstract
The effectiveness of the Free Nitrous Acid (FNA) sludge treatment was tested in the range from 0 to 3.0 mg N-HNO2/L with acidified and neutral pH. 4 h pre-treatment times were used and the specific methane production (SMP) investigated. Results show that between 50 and 100 mg/L of N-NO2−/L disappeared during the FNA pre-treatment, reducing its effectiveness. A minimum level of nitrite (174 mg N-NO2−/L tested in this study), independently of pH/FNA, was necessary to assure the presence of the chemical throughout the duration of the pre-treatment. Sludge viability was compromised while WAS solubilization and SMP were enhanced with nitrite concentrations of 174 mg N-NO2−/L or higher, even at low FNA levels (
- Published
- 2018
41. Effect of magnetite on anaerobic digestion treating saline wastewater: Methane production, biomass aggregation and microbial community dynamics
- Author
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Wei Wang, Kaili Ma, Yuyang Shi, Yanrui Cui, Tingting Chen, Shijie Shan, Jinghua Lv, and Zhiguo Cao
- Subjects
Environmental Engineering ,biology ,Renewable Energy, Sustainability and the Environment ,Methanogenesis ,Chemistry ,Microbiota ,Amendment ,Bioengineering ,General Medicine ,Wastewater ,biology.organism_classification ,Ferrosoferric Oxide ,Methanosaeta ,Salinity ,Anaerobic digestion ,chemistry.chemical_compound ,Bioreactors ,Microbial population biology ,Anaerobiosis ,Biomass ,Food science ,Methane ,Waste Management and Disposal ,Magnetite - Abstract
In this study, the effect of magnetite amendment on anaerobic digestion was investigated at three increasing salinity levels (0.5%, 1% and 2% NaCl). The amendment of magnetite enhanced the methane yield by 36.3%, 33.3% and 16.5% at low salinity (0.5% NaCl) and high salinity (1% and 2% NaCl), respectively. Meanwhile, a larger proportion of granules was obtained in the magnetite amended reactor (48.05% vs 33.16% at the end of operation). Microbial analysis suggested magnetite could induce more methanogenesis partnerships between hydrogenotrophic methanogens and syntrophic bacteria. Methanosaeta and Methanocorpusculum were the alternating dominant methanogens at low salinity and high salinity. While Streptococcus and Mesotoga were two prevalent bacteria that showed totally different transition tendency in two reactors. Additionally, the supplement of magnetite could relieve the suppression of methanogenesis-related gene expression caused by salinity, thus facilitated the higher methane production.
- Published
- 2021
42. The origin of waste activated sludge affects the enhancement of anaerobic digestion by free nitrous acid pre-treatment
- Author
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Nova Maulani, Kaili Li, Haoran Duan, Shihu Hu, Kai Yee Seo, Angelica Guerrero Calderon, Sergi Astals, Zhuan Khai Lim, Huijuan Li, Zhiguo Yuan, Jingjing Wan, and Catherine Macintosh
- Subjects
Pre treatment ,Nitrous acid ,Environmental Engineering ,Sewage ,Nitrous Acid ,Wastewater ,Pulp and paper industry ,Waste Disposal, Fluid ,Pollution ,chemistry.chemical_compound ,Anaerobic digestion ,Hydrolysis ,Bioreactors ,Activated sludge ,chemistry ,Biogas ,Environmental Chemistry ,Sewage treatment ,Anaerobiosis ,Methane ,Waste Management and Disposal - Abstract
Anaerobic digestion is a common stabilization method for treating primary sludge (PS) and waste activated sludge (WAS). However, its application is often limited by the degradation of WAS. Recent studies have demonstrated FNA to be an effective pre-treatment for enhancing WAS degradability, while having limited effect on PS degradability. WAS characteristics are impacted by wastewater treatment plant (WWTP) configuration and this study is the first to compare the effectiveness of FNA pre-treatment on WAS from WWTP with and without primary treatment. In this study, WAS samples were collected from four full-scale WWTPs with or without primary treatment. Sludge characterization, biomethane potential tests and mathematical modeling were conducted to assess the impacts of FNA pre-treatment on anaerobic digestion. The results showed that FNA pre-treatment was consistently effective for WAS from different WWTPs, while the extent of enhancement varied between WWTPs. For WAS from WWTPs without primary treatment, FNA pretreatment increased the rate of hydrolysis by 54–66% compared to 22–33% increase for WAS without primary treatment. In contrast, WAS from WWTPs with primary treatment experienced greater increases in methane potential (22–24%) compared to WAS from WWTPs without primary treatment (14–16%). These variances could be associated with primary treatment impacting the wastewater COD/N ratio and thus portion of extracellular polymetric substances (EPS) and cells in WAS. FNA pre-treatment targets the destruction of polymetric substances and cells, therefore WAS with a higher proportion of cells (i.e., WAS with primary treatment) experienced greater improvements in methane yield. Similarly, greater improvements in hydrolysis rate were observed for WAS from WWTP without primary sedimentation which contain higher proportions of large EPS molecules. Despite its consistent effectiveness on WAS samples, FNA pre-treatment was ineffective for improving the digestibility of high-rate activated sludge (HRAS).
- Published
- 2021
43. Efficient nitrogen removal from mainstream wastewater through coupling Partial Nitritation, Anammox and Methane-dependent nitrite/nitrate reduction (PNAM)
- Author
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Shihu Hu, Min Zheng, Jianhua Guo, Tao Liu, Yan Lu, and Zhiguo Yuan
- Subjects
Environmental Engineering ,Hydraulic retention time ,Nitrogen ,chemistry.chemical_element ,Wastewater ,Methane ,chemistry.chemical_compound ,Bioreactors ,Nitrate ,Ammonium Compounds ,Anaerobiosis ,Nitrite ,Waste Management and Disposal ,Nitrites ,Water Science and Technology ,Civil and Structural Engineering ,Nitrates ,Ecological Modeling ,Pollution ,chemistry ,Anammox ,Environmental chemistry ,Anaerobic oxidation of methane ,Denitrification ,Oxidation-Reduction - Abstract
The application of partial nitritation and anammox to remove nitrogen from mainstream wastewater is of great interest because of the potential to reduce energy cost and carbon dosage. However, this process confronts a dilemma of relatively high effluent nitrogen concentration (>10 mg N/L), owning to the unwanted prevalence of nitrite-oxidizing bacteria (NOB) and the intrinsic nitrate production by anammox bacteria. Here, a novel technology, named the one-stage PNAM, that integrates P artial N itritation, A nammox and M ethane-dependent nitrite/nitrate reduction reactions, was developed in a single membrane biofilm reactor (MBfR). With feeding of synthetic mainstream wastewater containing ∼50 mg NH4+-N/L at a hydraulic retention time of 12 h, more than 95% nitrogen was removed in the established one-stage PNAM process at a practically useful rate of 0.1 kg N/m3/d. Microbial community characterization and in-situ batch tests revealed a sophisticated microbial structure consisting of ammonia-oxidizing bacteria (AOB), anammox bacteria, nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) bacteria and archaea, and a small fraction of NOB and aerobic methanotrophs. The role of methane in removing nitrate was confirmed by switching on/off the methane supply, which relaxed the requirement for NOB suppression. In addition, the established system was relatively robust against temperature variations, evidenced by a total nitrogen removal efficiency above 80% at temperature as low as 14 ℃. The results provide a promising alternative for efficient nitrogen removal from domestic wastewater using methane as the sole carbon source.
- Published
- 2021
44. Biological Bromate Reduction Driven by Methane in a Membrane Biofilm Reactor
- Author
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Zhiguo Yuan, Jing-Huan Luo, Jianhua Guo, and Mengxiong Wu
- Subjects
0301 basic medicine ,Health, Toxicology and Mutagenesis ,010501 environmental sciences ,01 natural sciences ,Methane ,03 medical and health sciences ,chemistry.chemical_compound ,Perchlorate ,Nitrate ,Environmental Chemistry ,Nitrite ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology ,Ecology ,Chromate conversion coating ,biology ,Methanosarcina ,Bromate ,biology.organism_classification ,Pollution ,6. Clean water ,030104 developmental biology ,chemistry ,13. Climate action ,Environmental chemistry ,Carbon dioxide - Abstract
As a potent greenhouse gas with a greenhouse warming potential 28 times that of carbon dioxide over a time scale of 100 years, methane has been proven to be useful as an electron donor for the removal of various contaminants, e.g., nitrate, nitrite, perchlorate, and chromate, from contaminated water. However, microbial bromate reduction supported by methane has not been reported so far. Here, a lab-scale membrane biofilm reactor (MBfR) was set up to explore the feasibility of bromate reduction driven by methane under oxygen-limiting conditions. Long-term operational performance demonstrated that a complete reduction of bromate (BrO3–) to bromide (Br–) could be achieved, with 100% bromate removal efficiency under a volume loading of 1 mg of Br L–1 day–1. Volatile fatty acids (VFAs) were produced in the reactor (concentrations ranging from 1.81 to 27.9 mg/L) under oxygen-limiting conditions. High-throughput 16S rRNA gene sequencing indicated that Methanosarcina became the only dominate methane-oxidizing mic...
- Published
- 2017
45. An analytical model for shale gas transport in kerogen nanopores coupled with real gas effect and surface diffusion
- Author
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Ying Yin, Jianfei Zhang, and Zhiguo Qu
- Subjects
Surface diffusion ,Equation of state ,Real gas ,020209 energy ,General Chemical Engineering ,Organic Chemistry ,Analytical chemistry ,Energy Engineering and Power Technology ,Thermodynamics ,02 engineering and technology ,Methane ,chemistry.chemical_compound ,Viscosity ,Fuel Technology ,020401 chemical engineering ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Kerogen ,Slippage ,Knudsen number ,0204 chemical engineering ,Astrophysics::Galaxy Astrophysics - Abstract
Understanding the behavior of shale gas transport in kerogen is a key issue in predicting gas production. The reservoir structure is characterized by widespread micro/nanoscale pores, various occurrence states, and typical high pressure. An analytical model is proposed to effectively reveal the gas transport behavior in kerogen nanopores. The model can fully consider the real gas effect, gas slippage, and surface diffusion derived from absorbed gas. In particular, a method based on dense gas theory with the Redlich–Kwong equation of state is used to acquire the viscosity of shale gas under high pressure. The second-order slippage boundary condition coupled with surface diffusion is presented to describe the free gas slippage, and Langmuir isotherm theory and Fick’s law are adopted to calculate the surface diffusion. The real gas effect has a significant effect on the physical properties of methane, Knudsen number, and the flow behaviors of free gas and adsorbed gas. The surface diffusion velocity can enhance the free gas flow. The mass flow rate of total adsorbed gas increases as pore size increases, and its major influence is obtained from the induced free gas at the increased pore size. The slippage effect is reduced as the pressure increases and the temperature decreases. The absorbed gas comprises a substantial proportion of the total gas produced when the pore size is less than 2 nm. The combined influences of slippage effect and absorbed gas cannot be ignored when the pore size is less than 10 nm. This work provides a comprehensive and theoretical guidance for the effective development of shale gas.
- Published
- 2017
46. Comparative study of continuous-stirred and batch microwave pyrolysis of linear low-density polyethylene in the presence/absence of HZSM-5
- Author
-
Roger Ruan, Hongyu Peng, Lei Liu, Liangliang Fan, Paul Chen, Haiwei Jiang, Pei Huang, Sen Lv, Zhiguo Xiao, Wenguang Zhou, and Zheyang Su
- Subjects
Materials science ,020209 energy ,Mechanical Engineering ,02 engineering and technology ,Building and Construction ,Polyethylene ,Fluid catalytic cracking ,Pollution ,Industrial and Manufacturing Engineering ,Methane ,Catalysis ,Linear low-density polyethylene ,chemistry.chemical_compound ,Cracking ,General Energy ,020401 chemical engineering ,Chemical engineering ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,0204 chemical engineering ,Electrical and Electronic Engineering ,Selectivity ,Pyrolysis ,Civil and Structural Engineering - Abstract
A continuous-stirred microwave pyrolysis (CSMP) reactor was designed for linear low-density polyethylene (LLDPE) conversion. Its performance was compared with the batch microwave pyrolysis (BMP) under identical conditions. During the pyrolysis, the continuous-stirred system generated more condensate products with higher selectivity in long carbon chains (C14–C20), whereas the batch system was more selective for gas products with a higher proportion of methane. An ex-situ catalytic bed with HZSM-5 was assembled to upgrade pyrolysis vapors, corresponding to improved gasoline-range hydrocarbons and propylene production. The comparison of catalytic processes showed similar product yields for both configurations, with differences primarily on chemical species selectivity. For instance, the products from the continuous-stirred system had narrower carbon number distribution (C7–C10) and higher selectivity to mono-aromatics (72.3%). The proposed pathways for LLDPE conversion from the two systems showed slight differences in the thermal cracking process but similarities in the catalytic cracking process. During the catalytic processes, the potential net energy gain was 34.16 MJ/kg for CSMP and −38.86 MJ/kg for BMP, compared with the non-catalytic processes, when the figures were 9.85 MJ/kg and −42.86 MJ/kg, respectively.
- Published
- 2021
47. Greenhouse Gases Trade-Off from Ponds: An Overview of Emission Process and Their Driving Factors.
- Author
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Malyan, Sandeep K., Singh, Omkar, Kumar, Amit, Anand, Gagan, Singh, Rajesh, Singh, Sandeep, Yu, Zhiguo, Kumar, Jhlaesh, and Fagodiya, Ram K.
- Subjects
PONDS ,GREENHOUSE gases ,EMISSIONS (Air pollution) ,WATER depth ,BODIES of water ,WATER supply ,CARBON dioxide - Abstract
Inland water bodies (particularly ponds) emit a significant amount of greenhouse gases (GHGs), particularly methane (CH
4 ), carbon dioxide (CO2 ), and a comparatively low amount of nitrous oxide (N2 O) to the atmosphere. In recent decades, ponds (<10,000 m2 ) probably account for about 1/3rd of the global lake perimeter and are considered a hotspot of GHG emissions. High nutrients and waterlogged conditions provide an ideal environment for CH4 production and emission. The rate of emissions differs according to climatic regions and is influenced by several biotic and abiotic factors, such as temperature, nutrients (C, N, & P), pH, dissolved oxygen, sediments, water depth, etc. Moreover, micro and macro planktons play a significant role in CO2 and CH4 emissions from ponds systems. Generally, in freshwater bodies, the produced N2 O diffuses in the water and is converted into N2 gas through different biological processes. There are several other factors and mechanisms which significantly affect the CH4 and CO2 emission rate from ponds and need a comprehensive evaluation. This study aims to develop a decisive understanding of GHG emissions mechanisms, processes, and methods of measurement from ponds. Key factors affecting the emissions rate will also be discussed. This review will be highly useful for the environmentalists, policymakers, and water resources planners and managers to take suitable mitigation measures in advance so that the climatic impact could be reduced in the future. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
48. Sludge-Drying Lagoons: a Potential Significant Methane Source in Wastewater Treatment Plants
- Author
-
Ben van den Akker, Zhiguo Yuan, Yuting Pan, Liu Ye, Ronald S. Musenze, Ramon Ganigué Pagès, Pan, Yuting, Ye, Liu, van den Akker, Ben, Ganigue, Pages Ramon, Musenze, Ronald S, and Yuan, Zhiguo
- Subjects
diffusive methane ,010504 meteorology & atmospheric sciences ,temporal variability ,Sewage ,Wastewater ,010501 environmental sciences ,Waste Disposal, Fluid ,01 natural sciences ,generation ,nitrous-oxied emissions ,Environmental Chemistry ,activated-sludge ,0105 earth and related environmental sciences ,GHG footprint ,business.industry ,Australia ,Environmental engineering ,General Chemistry ,6. Clean water ,13. Climate action ,Greenhouse gas ,Sewage sludge treatment ,Environmental science ,Facultative lagoon ,Sewage treatment ,business ,Methane ,Waste disposal - Abstract
'Sludge-drying lagoons' are a preferred sludge treatment and drying method in tropical and subtropical areas due to the low construction and operational costs. However, this method may be a potential significant source of methane (CH4) because some of the organic matter would be microbially metabolized under anaerobic conditions in the lagoon. The quantification of CH4 emissions from lagoons is difficult due to the expected temporal and spatial variations over a lagoon maturing cycle of several years. Sporadic ebullition of CH4, which cannot be easily quantified by conventional methods such as floating hoods, is also expected. In this study, a novel method based on mass balances was developed to estimate the CH4 emissions and was applied to a full-scale sludge-drying lagoon over a three year operational cycle. The results revealed that processes in a sludge-drying lagoon would emit 6.5 kg CO2-e per megaliter of treated sewage. This would represent a quarter to two-thirds of the overall greenhouse gas (GHG) emissions from wastewater-treatment plants (WWTPs). This work highlights the fact that sludge-drying lagoons are a significant source of CH4 that adds substantially to the overall GHG footprint of WWTPs despite being recognized as a cheap and energy-efficient means of drying sludge. Refereed/Peer-reviewed
- Published
- 2016
49. Interactions of functional microorganisms and their contributions to methane bioconversion to short-chain fatty acids
- Author
-
Hui Chen, Lei Zhao, Jianhua Guo, and Zhiguo Yuan
- Subjects
Methanobacterium ,Environmental Engineering ,Bioconversion ,Microorganism ,0208 environmental biotechnology ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,7. Clean energy ,Methane ,chemistry.chemical_compound ,Bioreactors ,Nitrate ,Food science ,Nitrite ,Waste Management and Disposal ,Nitrites ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,chemistry.chemical_classification ,biology ,Ecological Modeling ,Methanosarcina ,Electron acceptor ,Fatty Acids, Volatile ,biology.organism_classification ,Pollution ,020801 environmental engineering ,chemistry ,Biofilms ,Oxidation-Reduction - Abstract
Methane bioconversion to value-added liquid chemicals has been proposed as a promising solution to augment the petroleum-dominated chemical market. Recent investigations have reported that various electron acceptors (e.g., nitrite and nitrate) are available to drive methane bioconversion to short-chain fatty acids (SCFAs). However, little is known about effects of the rate electron acceptor supplied on liquid chemical production from methane. Herein, three independent membrane biofilm reactors (MBfRs) feeding with respective nitrate, nitrite, combined nitrate and nitrite were operated under high and low rate condition in succession, to study whether feeding rate of electron acceptors could impact the methane bioconversion to SCFAs and the associated microbiological features. Long-term operation showed that all tested electron acceptors with a high supply rate were favorable for methane bioconversion to SCFAs (990.9 mg L−1d−1, 1695.7 mg L−1d−1, and 2425.7 mg L−1d−1), while under a low electron acceptor feeding rate, the SCFA production rate decreased to 8.9 mg L−1d−1, 16.8 mg L−1d−1, and 260.1 mg L−1d−1, respectively. Microbial community characterization showed that the biofilm was predominated by Methanosarcina, Methanobacterium, Propionispora and Clostridium. On the basis of the known metabolism characteristics of these microorganisms, it was assumed that these methanogens and fermenters contributed jointly to methane bioconversion to SCFAs. The findings could be helpful to understand the role of electron acceptor rate in methane bioconversion to liquid chemicals.
- Published
- 2021
50. Roles of Oxygen in Methane-dependent Selenate Reduction in a Membrane Biofilm Reactor: Stimulation or Suppression
- Author
-
Shihu Hu, Jianhua Guo, Mengxiong Wu, Chun-Yu Lai, Zhiguo Yuan, Yarong Song, and Yulu Wang
- Subjects
Environmental Engineering ,Methanotroph ,0208 environmental biotechnology ,chemistry.chemical_element ,Electron donor ,02 engineering and technology ,Selenic Acid ,010501 environmental sciences ,01 natural sciences ,Oxygen ,Selenate ,chemistry.chemical_compound ,Bioreactors ,RNA, Ribosomal, 16S ,Arthrobacter ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,biology ,Ecological Modeling ,Biofilm ,Variovorax ,biology.organism_classification ,Pollution ,020801 environmental engineering ,chemistry ,Biofilms ,Environmental chemistry ,Methane ,Oxidation-Reduction ,Selenium - Abstract
Although methane (CH4) has been proven to be able to serve as an electron donor for bio-reducing various oxidized contaminants (e.g., selenate (SeO42−)), little is known regarding the roles of oxygen in methane-based reduction processes. Here, a methane-based membrane biofilm reactor (MBfR) was established for evaluating the effects of oxygen supply rates on selenate reduction performance and microbial communities. The oxygen supply rate played a dual role (stimulatory or suppressive effect) in selenate reduction rates, depending on the presence or absence of dissolved oxygen (DO). Specifically, selenate reduction rate was substantially enhanced when an appropriate oxygen rate (e.g., 12 to 184 mg/L.d in this study) was supplied but with negligible DO. The highest selenate reduction rate (up to 34 mg-Se/L.d) was obtained under an oxygen supply rate of 184 mg/L.d. In contrast, excessive oxygen supply rate (626 mg/L.d) would significantly suppress selenate reduction rate under DO level of 3 mg/L. Accordingly, though the high oxygen supply rate (626 mg/L.d) would promote the expression of pmoA (5.9 × 109 copies g−1), the expression level of narG (a recognized gene to mediate selenate reduction) would be significantly downregulated (6.1 × 109 copies g−1), thus suppressing selenate reduction. In contrast, the expression of narG gene significantly increased to 2.8 × 1010 copies g−1, and the expression of pmoA gene could still maintain at 1.1 × 109 copies g−1 under an oxygen supply rate of 184 mg/L.d. High-throughput sequencing targeting 16S rRNA gene, pmoA, and narG collectively suggested Methylocystis acts as the major aerobic methanotroph, in synergy with Arthrobacter and Variovorax which likely jointly reduce selenate to selenite (SeO32−), and further to elemental selenium (Se0). Methylocystis was predominant in the biofilm regardless of variations of oxygen supply rates, while Arthrobacter and Variovorax were sensitive to oxygen fluctuation. These findings provide insights into the effects of oxygen on methane-dependent selenate reduction and suggest that it is feasible to achieve a higher selenate removal by regulating oxygen supply rates.
- Published
- 2021
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