28 results on '"Zhiguo Pei"'
Search Results
2. New insight into the adsorption of sulfadiazine on graphite-like biochars prepared at different pyrolytic temperatures
- Author
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Ziyu Zhang, Lixiang Sun, Zhiguo Pei, Huiqian Li, Lingqing Wang, Jie Ma, Yingming Li, Ruiqiang Yang, and Qinghua Zhang
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Renewable Energy, Sustainability and the Environment ,Strategy and Management ,Building and Construction ,Industrial and Manufacturing Engineering ,General Environmental Science - Published
- 2023
3. Mutual influence of copper and paraquat on their adsorption in soils
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Huanhua WANG, Zhiguo PEI, Guangcai CHEN, and Baoshan XING
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Soil Science - Published
- 2022
4. Spatial and temporal trends of polychlorinated naphthalenes in the Arctic atmosphere at Ny-Ålesund and London Island, Svalbard
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Tariku Bekele Gebru, Yingming Li, Cheng Dong, Yuxin Yang, Ruiqiang Yang, Zhiguo Pei, Qinghua Zhang, and Guibin Jiang
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Environmental Engineering ,Environmental Chemistry ,Pollution ,Waste Management and Disposal - Published
- 2023
5. An evaluation of the impact of traffic on the distribution of PAHs and oxygenated PAHs in the soils and moss of the southeast Tibetan Plateau
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Lijia, Wei, Zhigang, Yu, Chengcheng, Zhu, Yu, Chen, Zhiguo, Pei, Yingming, Li, Ruiqiang, Yang, Qinghua, Zhang, and Guibin, Jiang
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Environmental Engineering ,Environmental Chemistry ,Pollution ,Waste Management and Disposal - Abstract
Contaminants in high-altitude mountains such as the Tibetan Plateau (TP) have attracted extensive attention due to their potential impact on fragile ecosystems. Rapid development of the economy and society has promoted pollution caused by local traffic emissions in the TP. Among the pollutants emitted by traffic, polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (OPAHs) are of particular concern due to their high toxicity. The TP provides an environment to explore the degree and range of contribution for traffic-induced PAHs and OPAHs. In this study, soils and moss were collected at different altitudes and distances from the G318 highway in the southeast TP. The total concentrations of PAHs (∑
- Published
- 2023
6. Adsorption and photocatalytic reduction of aqueous Cr(VI) by Fe3O4-ZnAl-layered double hydroxide/TiO2 composites
- Author
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Yanting Yang, Jing Li, Tao Yan, Zhiguo Pei, Liangguo Yan, and Rixin Zhu
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Langmuir ,Materials science ,Aqueous solution ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Isothermal process ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Dielectric spectroscopy ,Biomaterials ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Adsorption ,chemistry ,Photocatalysis ,Hydroxide ,Composite material ,Hexavalent chromium ,0210 nano-technology - Abstract
To evaluate the synergetic adsorption capacity of layered double hydroxide (LDH) and photocatalytic reduction property of TiO2 for aqueous Cr(VI), the Fe3O4-ZnAl-LDH and TiO2 composites (FLT) were prepared via sol-gel method. The removal efficiency of FLT composites for Cr(VI) changed with the mass ratio of Fe3O4-LDH/TiO2, and the optimal ratio was 20% (FLT-2). The adsorption efficiencies of 100 mg FLT-2 were 74% and 64% for 20 and 50 mg/L Cr(VI) solution, and the total removal ratios of Cr(VI) were all over 97% after UV irradiation. The experimental data of adsorption kinetic, adsorption isothermal, and photocatalytic reduction were consistent with the pseudo-second-order, Langmuir, and first-order reaction equations, respectively. From the X–ray photoelectron spectra analysis, FLT composites adsorbed Cr(VI) directly via surface complexation, also reduced aqueous Cr(VI) to Cr(III). The photocurrent and electrochemical impedance spectroscopy of FLT composites indicated the photo-induced electron-hole pairs were separated effectively. The regeneration results show that the FLT composites had good stability and reusability after five consecutive cycles. Therefore, FLT composites are promising materials in the disposal of wastewater containing Cr(VI).
- Published
- 2020
7. Single-Particle Analysis of Micro/Nanoplastics by Hyphenated Sem-Raman Technique
- Author
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Qinghua Zhang, Gang Li, Zhiruo Yang, Zhiguo Pei, Yingming Li, Ruiqiang Yang, Yong Liang, and Guibin Jiang
- Published
- 2022
8. Occurrence, Spatial Distribution, and Sources of Pfass in the Water and Sediment from Lakes in the Tibetan Plateau
- Author
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Yu Chen, Lijia Wei, Wei Luo, Ning Jiang, Yali Shi, Pin Zhao, Bila Ga, Zhiguo Pei, Yingming Li, Ruiqiang Yang, and Qinghua Zhang
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Fluorocarbons ,Geologic Sediments ,China ,History ,Environmental Engineering ,Polymers and Plastics ,Health, Toxicology and Mutagenesis ,Water ,Tibet ,Pollution ,Industrial and Manufacturing Engineering ,Lakes ,Alkanesulfonic Acids ,Environmental Chemistry ,Business and International Management ,Waste Management and Disposal ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
Per-and polyfluoroalkyl substances (PFASs) are omnipresent globally and received increasing attention recently. However, there are limited data on PFASs in the Tibetan Plateau (TP), a remote high-altitude mountain region, which is regard as an important indicator region to study long-range transport behaviors of contaminants. This study investigates the occurrence, distribution, partitioning behavior, and sources of 26 PFASs in water and sediments from the four lakes of TP. The ΣPFAS concentrations ranged from 338 to 9766 pg Lsup-1/supin water, and 12.2-414 pg gsup-1/supdry weight in sediments. Perfluorobutanonic acid (PFBA) and perfluorooctane sulfonate (PFOS) were detected in all samples. Qinghai Lake had the highest ΣPFAS concentrations in both water and sediments, while the Ranwu Lake had the lowest. The functional groups and CFsub2/submoiety units were investigated as essential factors influencing the partition behavior. Principal component analysis (PCA) combined back-trajectory was used to infer possible sources of PFASs. The results suggested that the main source of PFASs in Yamdrok Lake, Namco Lake, and Ranwu Lake on southern TP were mainly originated from South Asia via long-range atmospheric transport (LRAT); while for the Qinghai Lake of northern TP, LRAT, local emissions, and tourism activities were the primary sources of PFASs.
- Published
- 2022
9. Insight into the oxidation of glutathione mediated by black carbon from three typical emission sources
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Jie Ma, Lingyun Li, Ziyu Zhang, Zhiguo Pei, Peijie Zuo, Huiqian Li, Ruiqiang Yang, Yingming Li, and Qinghua Zhang
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Coal ,Soot ,Health, Toxicology and Mutagenesis ,Humans ,Hydrogen Peroxide ,General Medicine ,Reactive Oxygen Species ,Toxicology ,Oxidation-Reduction ,Glutathione ,Pollution ,Carbon - Abstract
Black carbon (BC) is released into the atmosphere in large quantities from different emission sources each year and poses a serious threat to human health. These BC possessed a variety of characteristics and different mediation abilities for the reactive oxygen species (ROS) generation. In this study, we collected BC (i.e., diesel BC, coal BC and wood BC) from three typica emission sources, and examined their mediation abilities to the oxidation of glutathione (GSH). Results showed that all three BC significantly promoted the GSH oxidation, and the mediation efficiencies were as follows: diesel BC coal BC wood BC. In comparison with the water-soluble fraction, the mediation abilities of three BC mainly came from their solid phase fractions. In the coal BC and wood BC systems, the oxidation of GSH was attributed to the catalysis of transition metals in BC. By contrast, the transition metals, phenolic -OH and persistent free radicals in diesel BC were identified as the active sites responsible for the GSH oxidation. In addition, the graphitic surface of diesel BC could synergize with these active sites to accelerate the oxidation of GSH. Under the catalysis of BC, dissolved oxygen was first reduced to ROS (O
- Published
- 2023
10. Legacy and novel brominated flame retardants in air of Ny-Ålesund, Arctic from 2011 to 2019
- Author
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Siyuan Xiong, Yanfen Hao, Jianjie Fu, Pu Wang, Ruiqiang Yang, Zhiguo Pei, Yingming Li, An Li, Qinghua Zhang, and Guibin Jiang
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Health, Toxicology and Mutagenesis ,Halogenated Diphenyl Ethers ,General Medicine ,Toxicology ,Pollution ,Gas Chromatography-Mass Spectrometry ,Environmental Monitoring ,Flame Retardants - Abstract
Concentrations of polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs) in the atmosphere of Ny-Ålesund, Svalbard, were investigated. Passive air samples were collected for eight consecutive one-year periods from August 2011 to August 2019 at seven Arctic sampling sites. High-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC-HRMS) and gas chromatography coupled with election capture negative ionization mass spectrometry (GC-NCI-MS) were employed for PBDE and NBFR analysis, respectively. The median concentrations of Ʃ
- Published
- 2022
11. Novel brominated and organophosphate flame retardants in the atmosphere of Fildes Peninsula, West Antarctica: Continuous observations from 2011 to 2020
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Yanfen, Hao, Siyuan, Xiong, Pu, Wang, Ruiqiang, Yang, Zhiguo, Pei, Yingming, Li, Qinghua, Zhang, and Guibin, Jiang
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Environmental Engineering ,Atmosphere ,Health, Toxicology and Mutagenesis ,Antarctic Regions ,Environmental Chemistry ,Pollution ,Waste Management and Disposal ,Organophosphates ,Environmental Monitoring ,Flame Retardants ,Phosphates - Abstract
Novel brominated flame retardants (NBFRs) and organophosphate esters (OPEs) have been widely detected in various environmental matrices worldwide and raised public concerns in recent years. However, few studies reported their occurrence and temporal trend in Antarctic air. In this study, concentrations, distribution, and temporal trends of NBFRs and OPEs in the air of Fildes Peninsula, West Antarctica, were investigated using XAD resin-based passive air sampling from January 2011 to January 2020. Air concentrations of the total OPEs (Σ
- Published
- 2022
12. Synergetic mediation of reduced graphene oxide and Cu(II) on the oxidation of 2-naphthol in water
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Shuzhen Zhang, Jie Ma, Bei Wen, Jieli Xie, Zhiguo Pei, Lingyun Li, Baoshan Xing, and Lingqing Wang
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010504 meteorology & atmospheric sciences ,Health, Toxicology and Mutagenesis ,Radical ,Oxide ,Trimer ,Naphthols ,010501 environmental sciences ,Toxicology ,Photochemistry ,01 natural sciences ,Redox ,law.invention ,chemistry.chemical_compound ,Adsorption ,law ,Environmental Restoration and Remediation ,0105 earth and related environmental sciences ,Autoxidation ,Graphene ,Water ,General Medicine ,Pollution ,Nanostructures ,chemistry ,Graphite ,Reactive Oxygen Species ,Oxidation-Reduction ,2-Naphthol ,Copper ,Water Pollutants, Chemical - Abstract
Reduced graphene oxide (rGO) is one of the most widely used carbon nanomaterials. When it is released into the environment, rGO can markedly affect the transformation of many pollutants, and change their fate and risk. In this work, the synergetic effects of rGO and Cu(II) on the oxidation of 2-naphthol were examined in water in the dark. It was found that the coexistence of rGO and Cu(II) significantly promoted the oxidation of 2-naphthol. Corresponding products were identified as the coupling oligomers of 2-naphthol (dimer, trimer and tetramer) and hydroxylated compounds (OH-2-naphthol, OH-dimer, di–OH–dimer and naphthoquinone derivatives). In the oxidation reaction, rGO played dual roles, i.e. adsorbent and electron-transfer mediator. rGO firstly adsorbed Cu(II) and 2-naphthol on its surface, and then transferred electrons from 2-naphthol to Cu(II) to yield 2-naphthol radicals and Cu(I). 2-Naphthol radicals coupled to each other to form different oligomers of 2-naphthol. Cu(I) was re-oxidized back to Cu(II) by dissolved oxygen, which sustained the continuous oxidation of 2-naphthol. During the autoxidation of Cu(I), reactive oxygen species were generated, which further reacted with 2-naphthol to form hydroxylated products. These findings provide new insights into the risk assessment of rGO and 2-naphthol in aquatic environments.
- Published
- 2019
13. Removal of Cu2+, Cd2+ and Pb2+ from aqueous solutions by magnetic alginate microsphere based on Fe3O4/MgAl-layered double hydroxide
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Bin Du, Liangguo Yan, Zhiguo Pei, Haiqin Yu, Yan Chen, and Sun Junhao
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Aqueous solution ,Calcium alginate ,Materials science ,Energy-dispersive X-ray spectroscopy ,Langmuir adsorption model ,Infrared spectroscopy ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Biomaterials ,chemistry.chemical_compound ,symbols.namesake ,Colloid and Surface Chemistry ,Adsorption ,chemistry ,symbols ,Hydroxide ,Freundlich equation ,0210 nano-technology ,Nuclear chemistry - Abstract
In this work, the magnetic alginate microsphere of Fe3O4/MgAl-LDH (Fe3O4/LDH-AM) was prepared by immobilizing the Fe3O4/LDH with calcium alginate (CA) and was used to remove Cd2+, Pb2+, and Cu2+ from aqueous solutions. The obtained Fe3O4/LDH-AM was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller surface area determination. The results indicated that the surface groups of the alginate and LDH were retained and so was the crystal structure in the alginate microsphere. The adsorption performance of the Fe3O4/LDH-AM for Cd2+, Pb2+, and Cu2+ in aqueous solutions was evaluated by batch and column adsorption experiments. The effects of adsorption conditions, kinetics, isotherms, mechanisms, and potential applications were investigated. The adsorption kinetic data conformed to the pseudo-second-order kinetic equation, and the isotherm data fit well with the Freundlich and Langmuir isotherm models. The adsorption mechanism of Cd2+, Pb2+, and Cu2+ by the Fe3O4/LDH-AM entailed complexation and precipitation. The experimental breakthrough curves were correlated with the Thomas model. Moreover, the Fe3O4/LDH-AM displayed superior regeneration and reusability. These results suggest that the Fe3O4/LDH-AM is an efficient adsorbent for the removal of heavy metals and can be effectively employed in practical applications.
- Published
- 2018
14. Cosorption of Zn(II) and chlortetracycline onto montmorillonite: pH effects and molecular investigations
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Shuhan Tian, Xiulan Yan, Eder C. Lima, Zhiguo Pei, Joerg Rinklebe, Xiao Yang, Shengsen Wang, Tao Liang, Lingqing Wang, and Xiaoxiao Han
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Chlortetracycline ,Environmental Engineering ,Health, Toxicology and Mutagenesis ,Ionic bonding ,chemistry.chemical_element ,Zinc ,chemistry.chemical_compound ,symbols.namesake ,medicine ,Environmental Chemistry ,Waste Management and Disposal ,Extended X-ray absorption fine structure ,Langmuir adsorption model ,Sorption ,Hydrogen-Ion Concentration ,Pollution ,Montmorillonite ,chemistry ,Bentonite ,symbols ,Adsorption ,Absorption (chemistry) ,Nuclear chemistry ,medicine.drug - Abstract
Ionic antibiotics and metals generally coexist, and their interaction can affect their sorption behaviors onto soil minerals, therefore determining their environmental hazards. This study investigated the sorption and cosorption of Zn(II) and chlortetracycline (CTC) onto montmorillonite at different solution pH (3−10) using batch experiments and extended X-ray absorption fine structure (EXAFS) analysis. The Langmuir model could reproduce well the sorption isotherms of Zn(II) and CTC. The presence of CTC/Zn(II) could promote the maximum sorption capacity (Qm) of Zn(II)/CTC, based on site energy distribution (SED) theory. Generally, Zn(II) sorption increased with pH increasing. Comparatively, CTC sorption decreased as pH increased till approximately pH 5.0, then increased continuously with pH increasing. Both CTC and Zn(II) co-existence enhanced their individual sorption in both acidic and neutral environments. The processes behind CTC and Zn(II) sorption mainly included cation exchange and surface complexation. The EXAFS data evidenced that the presence of CTC could alter the species of Zn(II) on montmorillonite via surface complexation at pH 4.5 and 7.5, with Zn-CTC complexes being the predominant species on montmorillonite at pH 7.5. At pH 9.5, Zn(II) may exist onto montmorillonite in precipitated form similar to Zn-Al hydrotalcite-like compound (HTlc) regardless of CTC presence.
- Published
- 2022
15. First report on hydroxylated and methoxylated polybrominated diphenyl ethers in terrestrial environment from the Arctic and Antarctica
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Guibin Jiang, Qinghua Zhang, Ruiqiang Yang, Pu Wang, Huizhong Sun, Zhiguo Pei, and Yingming Li
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Food Chain ,Environmental Engineering ,ved/biology ,Health, Toxicology and Mutagenesis ,ved/biology.organism_classification_rank.species ,Antarctic Regions ,Vegetation ,Pollution ,Soil ,Polybrominated diphenyl ethers ,Congener ,Arctic ,Dry weight ,Environmental chemistry ,Terrestrial plant ,Halogenated Diphenyl Ethers ,Humans ,Environmental Chemistry ,Dominance (ecology) ,Environmental science ,Terrestrial ecosystem ,Waste Management and Disposal ,Environmental Monitoring - Abstract
Terrestrial plants, which account for the world’s largest biomass and constitute the basis of most food webs, take up, transform, and accumulate organic chemical contaminants from the ambient environment. In this study, we determined the concentrations and congener profiles of polybrominated diphenyl ethers (PBDEs) and hydroxylated and methoxylated polybrominated diphenyl ethers (OH-PBDEs and MeO-PBDEs) in surface soil and vegetation samples collected from the Arctic (Svalbard) and Antarctica (King George Island) during the Chinese Scientific Research Expeditions. The concentrations of total PBDEs (∑PBDEs) in soil and vegetation samples collected from the Arctic (5.6–270 pg/g dry weight) were higher than those from Antarctica (2.3–33 pg/g dw), whereas the concentrations of ∑MeO-PBDEs and ∑OH-PBDEs were lower in Arctic terrestrial samples (n.d.–0.75 and 0.0008–1.1 ng/g dw, respectively) than in samples from Antarctica (0.007–4.0 and 0.034–25 ng/g dw, respectively). Long-range atmospheric transport and human activities were potential sources of PBDEs in polar regions, whereas the dominance of ortho-substituted MeO-PBDE and OH-PBDE congeners in terrestrial matrices indicated the importance of natural sources. To the best of our knowledge, this study represents the first report on the levels and behaviors of MeO-PBDEs and OH-PBDEs in terrestrial environment of polar regions.
- Published
- 2022
16. Substituent effects on the oxidation reactions of 4-nitrophenol, phenol, 4-methylpheol, and 4-methoxyphenol mediated by reduced graphene oxide in water
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Zhiguo Pei, Lingyun Li, Shuzhen Zhang, Chunmei Li, Jieli Xie, Bei Wen, and Lixiang Sun
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Chemistry ,Radical ,Oxide ,Substituent ,4-Nitrophenol ,02 engineering and technology ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,01 natural sciences ,Medicinal chemistry ,Redox ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Reaction rate constant ,Phenol ,Oxidative coupling of methane ,0210 nano-technology ,0105 earth and related environmental sciences - Abstract
Substituent effects of 4-nitrophenol (4-NP), phenol (PE), 4-methylpheol (4-MP), and 4-methoxyphenol (4-MOP) on their oxidative coupling reactions mediated by reduced graphene oxide (rGO) were examined using a batch method. The reaction products were identified as the oligomers of their individual parent compound, and C C and C O coupling between phenolic radicals were the main reaction pathways. The oxidative kinetics were well described with pseudo-first order model. The rate constants (kobs) of 4-NP, PE, 4-MP and 4-MOP were 0.47 × 10−3, 1.00 × 10−3, 2.03 × 10−3, and 3.53 × 10−3 h−1, respectively, following the order 4-NP H)), suggesting that BDE(O H) was an effective indicator to predict the oxidation susceptibility of phenolic compounds in rGO system. Dissolved oxygen played a critical role in the oxidation reactions through the formation of superoxide anion (O2 −) on rGO. These O2 − further cleaved the O H bond of phenolic compounds to produce phenolic radicals, which interacted each other and led to the following oxidative coupling reactions. The finding of this study is important for predicting the environmental fate of rGO and phenolic compounds.
- Published
- 2018
17. Novel brominated flame retardants (NBFRs) in soil and moss in Mt. Shergyla, southeast Tibetan Plateau: Occurrence, distribution and influencing factors
- Author
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Peijie Zuo, Chu Wang, Hao Xian, Jingya Lv, Guibin Jiang, Qinghua Zhang, Ruiqiang Yang, Yingming Li, Yanfen Hao, and Zhiguo Pei
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geography ,Plateau ,geography.geographical_feature_category ,biology ,Soil test ,Health, Toxicology and Mutagenesis ,Bryophyta ,General Medicine ,Tibet ,Toxicology ,biology.organism_classification ,Pollution ,Moss ,Soil ,Environmental chemistry ,Soil water ,Halogenated Diphenyl Ethers ,Environmental science ,Environmental Monitoring ,Flame Retardants - Abstract
Research on the environmental fate and behavior of novel brominated flame retardants (NBFRs) remains limited, especially in the remote alpine regions. In this study, the concentrations and distributions of NBFRs were investigated in soils and mosses collected from two slopes of Shergyla in the southeast of the Tibetan Plateau (TP), to unravel the environmental behaviors of NBFRs in this background area. The total NBFR concentrations (∑7NBFRs) ranged from 34.2 to 879 pg/g dw in soil and from 72.8 to 2505 pg/g dw in moss. ∑7NBFRs in soil samples collected in 2019 were significantly higher than those in 2012 (p
- Published
- 2021
18. Reduced graphene oxide-catalyzed oxidative coupling reaction of 4-methoxyphenol in aerobic aqueous solution
- Author
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Zhiguo Pei, Bei Wen, Baoshan Xing, Lingyun Li, Lixiang Sun, and Jieli Xie
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Aqueous solution ,Chemistry ,Radical ,Dimer ,Oxide ,Trimer ,02 engineering and technology ,General Chemistry ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,General Materials Science ,Oxidative coupling of methane ,Hydroxyl radical ,0210 nano-technology ,0105 earth and related environmental sciences - Abstract
Three reduced graphene oxide (rGO) with different defect contents were prepared at 250, 600 and 1000 °C, respectively, using thermal reduction method, and their effects on the oxidative coupling processes of 4-methoxyphenol (MOP) in aqueous solution were investigated. In the presence of rGOs, the oxidation of MOP was dramatically accelerated. At the same surface area dose, the catalytic efficiencies of three rGOs followed an ascending order of rGO 250 ≤ rGO 600 1000 . Using liquid chromatography-mass spectrometry and molecular modeling computation, we identified the coupling products (dimer, trimer, and tetramer), and revealed that ortho C O and ortho-ortho C C coupling between two MOP radicals were the main reaction pathways. Dissolved oxygen and structural defects of rGOs played important roles in the oxidation of MOP. It is proposed that dissolved oxygen reacted with the defect sites of rGO to produce surface-bound superoxide species, which captured H atom from the phenolic hydroxyl group of MOP to generate MOP radical and H 2 O 2 . A portion of H 2 O 2 can be catalyzed further by rGO to hydroxyl radical, which continued to react with MOP to produce MOP radical and H 2 O.
- Published
- 2017
19. Transformation of hydroquinone to benzoquinone mediated by reduced graphene oxide in aqueous solution
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Lingyun Li, Zhiguo Pei, Jieli Xie, Shuzhen Zhang, Lixiang Sun, and Chunmei Li
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Aqueous solution ,Semiquinone ,Autoxidation ,Hydroquinone ,Graphene ,Inorganic chemistry ,Oxide ,chemistry.chemical_element ,General Chemistry ,Oxygen ,Benzoquinone ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,General Materials Science - Abstract
The mediation effect of reduced graphene oxide (rGO) on the oxidative transformation of 1,4-hydroquinone (H(2)Q) to 1,4-benzoquinone (BQ) in aqueous solution was investigated using a batch method and electron paramagnetic resonance. The results showed that the autoxidation of H(2)Q was spin-restricted and extremely slow in acidic and neutral pH range, but this process can be dramatically accelerated when rGO was added. In the presence of 33.3 mg L-1 rGO, more than 76.0% of H(2)Q was oxidized to BQ within 36 h. The enhancement effects of rGO were attributed to the combined contribution of the high chemical reactivity of graphenic edges and defects on rGO and the high electron conductivity of graphene basal surface of rGO. It is proposed that dissolved oxygen reacted with graphenic edges and defects of rGO to produce surface-bound oxygen intermediates, which capture H atoms from the phenolic hydroxyl groups of H(2)Q and facilitate the generation of semiquinone radical (SQ(center dot-)). The generated SQ(center dot-) continued to transfer an electron to molecular oxygen to yield superoxide radical (OF) and BQ. As a chain-carrying radical, OF further reacted with H(2)Q to produce SQ(center dot-) and H2O2. (C) 2015 Elsevier Ltd. All rights reserved.
- Published
- 2015
20. Adsorption kinetics, isotherms and thermodynamics of Cr(III) on graphene oxide
- Author
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Jieli Xie, Jitao Lv, Lingyun Li, Chunmei Li, Shuzhen Zhang, Shuang Yang, Bei Wen, and Zhiguo Pei
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Kinetics ,Inorganic chemistry ,Oxide ,chemistry.chemical_element ,Langmuir adsorption model ,Thermodynamics ,Endothermic process ,Chromium ,symbols.namesake ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Adsorption ,chemistry ,Ionic strength ,symbols ,Physical chemistry ,Fourier transform infrared spectroscopy - Abstract
The adsorption kinetics, isotherms and thermodynamics of Cr(III) on graphene oxide (GO) were studied. The adsorption kinetic data were well described with pseudo-second-order model and the equilibrium data were well fitted by Langmuir model. The calculated thermodynamic parameters indicated that the adsorption of Cr(III) on GO was spontaneous and endothermic. The maximum adsorption capacity of Cr(III) on GO at pH 5.0 and T=296 K was about 92.65 mg g(-1), which was higher than other reported adsorbents. It was found that the adsorption of Cr(III) on GO was strongly dependent on solution pH, but weakly dependent on ionic strength. Fourier transform infrared (FTIR) spectra suggested that Cr(III) was adsorbed on GO mainly through the formation of inner-sphere complexes with the O-containing functional groups on GO surface. Results in this study suggested that GO was a suitable material for the preconcentration and removal of Cr(III) from water. (C) 2014 Elsevier B.V. All rights reserved.
- Published
- 2014
21. Effects of humic acid on copper adsorption onto few-layer reduced graphene oxide and few-layer graphene oxide
- Author
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Lirong Zheng, Shuang Yang, Zhiguo Pei, Bei Wen, Rixiang Huang, Yaning Xie, Xiao-quan Shan, Lingyun Li, Shuzhen Zhang, Chunmei Li, and Jing Zhang
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chemistry.chemical_classification ,Materials science ,Extended X-ray absorption fine structure ,Graphene ,Inorganic chemistry ,Oxide ,Infrared spectroscopy ,chemistry.chemical_element ,General Chemistry ,Copper ,law.invention ,chemistry.chemical_compound ,Adsorption ,chemistry ,law ,Humic acid ,General Materials Science ,Absorption (chemistry) - Abstract
The effects of humic acid (HA) on copper (Cu(II)) adsorption onto few-layer reduced graphene oxide (FRGO) and few-layer graphene oxide (FGO) were investigated using a batch equilibration method, micro-Fourier transform infrared spectroscopy, and extended X-ray absorption fine structure spectroscopy (EXAFS). The results showed that HA was adsorbed on FRGO through it-it interaction. The adsorbed HA introduced O-containing functional groups and negative charges to FRGO surfaces, increasing Cu(II) adsorption through chemical complexation and electrostatic attraction. In contrast, HA was adsorbed onto FGO mainly through polar interactions, due to its rich O-containing functional groups. The adsorbed HA had little effect on Cu(II) adsorption onto FGO because the shielding effect of HA on Cu(II) adsorption was offset by newly introduced adsorption sites of HA on FGO. EXAFS results suggested that Cu(II) was adsorbed on FRGO and FGO mainly through the coordination with their O-containing functional groups. When HA was added at pH 4.0 and 6.0, more Cu(II) was adsorbed on HA-coated FRGO. At pH 8.0, a portion of Cu(II) in solution precipitated on FRGO surface, while the presence of HA led to the formation of FRGO-HA-Cu ternary surface complexes instead of Cu(II) precipitation. (C) 2014 Elsevier Ltd. All rights reserved.
- Published
- 2014
22. Study on nanocomposite Ti–Al–Si–Cu–N films with various Si contents deposited by cathodic vacuum arc ion plating
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C.M. Muders, Zhiguo Pei, Jun Gong, Xin Jiang, Sun Chunshui, Jing Shi, and Aditya Kumar
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Materials science ,Nanocomposite ,Silicon ,Ion plating ,Metallurgy ,General Physics and Astronomy ,chemistry.chemical_element ,Surfaces and Interfaces ,General Chemistry ,Vacuum arc ,Nitride ,Condensed Matter Physics ,Microstructure ,Surfaces, Coatings and Films ,X-ray photoelectron spectroscopy ,chemistry ,Composite material ,Elastic modulus - Abstract
In this study, nanocomposite Ti-Al-Si-Cu-N films were deposited on high speed steel substrates by the vacuum cathode arc ion plating (AIP) technique. By virtue of X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FESEM), the influence of silicon content on the film microstructure and characteristics was investigated systematically, including the chemical composition, crystalline structure as well as cross-section morphologies. With increasing the silicon content, a deterioration of the preferred orientation and a dense globular structure were detected. In the meanwhile, atomic force microscopy (AFM), nano-indentation, Rockwell indenter and reciprocating test were also utilized to analyze the hardness, elastic modulus, H-3/E-2, friction coefficient, adhesive strength and wear rate of the Ti-Al-Si-Cu-N films. The results showed that an optimal silicon content correlated with the best mechanical and tribological properties of the presented Ti-Al-Si-Cu-N films existed. With increasing the silicon content, the hardness, elastic modulus and the ratio H-3/E-2 first were improved gradually, and then were impaired sharply again. When the silicon content reached to 6 at.%, the film possessed the highest hardness, elastic modulus and ratio H-3/E-2 of approximately 24 GPa, 218 GPa and 0.31, respectively. Besides, films containing both 6 at.% and 10 at.% Si contents obtained a relatively low friction coefficient and a good adhesive strength. The wear rate decreased with an increase in hardness, with the highest hardness corresponding to a wear rate around 1.3 x 10(-5)mm(3)/(N m) of the film with 6 at.% Si content. The correlations between hardness and tribological properties for the films were also examined. The essence of above phenomena was attributed to the variations of microstructure and morphologies in the films induced by the increasing silicon content. (C) 2012 Elsevier B. V. All rights reserved.
- Published
- 2012
23. Coadsorption of copper and perfluorooctane sulfonate onto multi-walled carbon nanotubes
- Author
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Shuzhen Zhang, Yanping Zhou, Guangcai Chen, Jing Fang, Xiao-quan Shan, Bei Wen, Zhiguo Pei, and Jitao Lv
- Subjects
X-ray absorption spectroscopy ,Chemistry ,General Chemical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,Sorption ,General Chemistry ,Carbon nanotube ,Copper ,Industrial and Manufacturing Engineering ,law.invention ,chemistry.chemical_compound ,Adsorption ,Sulfonate ,law ,Desorption ,Zeta potential ,Environmental Chemistry - Abstract
Multi-walled carbon nanotubes (MWCNTs) are superadsorbents for perfluorooctane sulfonate (PFOS) and heavy metals, which coexist in wastewater. The interaction between PFOS and Cu(II) with regard to their adsorption and desorption on MWCNTs was evaluated in this study. The adsorption of PFOS on MWCNTs enhanced with an increase of Cu(II). Desorption of PFOS showed no hysteresis without Cu(II), while pronounced hysteresis with Cu(II). Increases of the adsorption and the occurrence of desorption hysteresis of PFOS in the presence of Cu(II) may due to the PFOS adsorption via a Cu(II) bridge. The adsorption of Cu(II) increased with an increase of PFOS. The desorption hysteresis factors in the presence of PFOS were lower than those in the absence of PFOS. Increases of the adsorption and decreases of desorption hysteresis factors may be attributed to the Cu(II) adsorption via a PFOS bridge. Results obtained by X-ray absorption spectroscopy verified the formation of inner-sphere complexes between Cu(II) and functional groups of MWCNTs without PFOS, while out-sphere complexes with large amount of PFOS. The effect of Cu(II) and PFOS adsorption on the zeta potential of MWCNTs was also studied. The results showed that the coexistence of Cu(II) and PFOS greatly affects their sorption and desorption behaviors on MWCNTs thereby their fate and transport in wastewater. (C) 2012 Elsevier B.V. All rights reserved.
- Published
- 2012
24. Sorption of aromatic hydrocarbons onto montmorillonite as affected by norfloxacin
- Author
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Zhiguo Pei, Xiao-quan Shan, Jingjing Kong, and Bei Wen
- Subjects
Magnetic Resonance Spectroscopy ,Environmental Engineering ,Health, Toxicology and Mutagenesis ,Inorganic chemistry ,Quinoline ,Sorption ,Hydrogen-Ion Concentration ,Phenanthrene ,Pollution ,Hydrocarbons ,Anti-Bacterial Agents ,chemistry.chemical_compound ,Montmorillonite ,Solubility ,chemistry ,Zwitterion ,Spectroscopy, Fourier Transform Infrared ,Bentonite ,Environmental Chemistry ,Pyrene ,Adsorption ,Methylene ,Waste Management and Disposal ,Norfloxacin ,Naphthalene - Abstract
Effect of norfloxacin (Nor) on the sorption of 1,3-dinitrobenzene (1,3-DNB), and PAHs (naphthalene (NAPH), phenanthrene (PHEN) and pyrene (PYR)) to K(+)-montmorillonite was studied. Nor suppressed 1,3-DNB sorption due to their competition for the same sorption sites. 1,3-DNB was sorbed on K(+)-montmorillonite surface via cation-polar interaction and n-π electron donor-acceptor interaction. Nor also was sorbed on these sites through cation exchange, cation bridging and/or surface complexation. Nor increased three PAHs sorption on montmorillonite and the enhanced magnitude was positively correlated with the π-donor strength of three PAHs. The enhanced sorption of PAHs by Nor was primarily attributed to π-π interaction between π-electron-depleted quinoline ring of Nor and π-electron-rich PAHs. Compared with cation (Nor(+)) and anion (Nor(-)), zwitterion (Nor(±)) of Nor increased PHEN and PYR sorption more pronounced due to additional cation-π interaction between the sorbed Nor(±) and PAHs. (1)H NMR spectrum provided direct evidence for π-π and cation-π complexation between PAHs and Nor(+) in solution by ring-current-induced upfield chemical shifts of amino group and methylene group of Nor(+).
- Published
- 2012
25. Adsorption of diuron and dichlobenil on multiwalled carbon nanotubes as affected by lead
- Author
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Zhiguo Pei, Guangcai Chen, Lirong Zheng, Huanhua Wang, J. Z. Zhang, Xiao-quan Shan, and Yaning Xie
- Subjects
Environmental Engineering ,Health, Toxicology and Mutagenesis ,Inorganic chemistry ,chemistry.chemical_element ,Carbon nanotube ,Oxygen ,law.invention ,Adsorption ,law ,Specific surface area ,Nitriles ,Environmental Chemistry ,Waste Management and Disposal ,Herbicides ,Nanotubes, Carbon ,Hydrogen bond ,Water ,Microporous material ,Pollution ,Solvation shell ,Lead ,chemistry ,Diuron ,Absorption (chemistry) ,Hydrophobic and Hydrophilic Interactions ,Water Pollutants, Chemical - Abstract
The effect of lead on the adsorption of diuron and dichlobenil on multiwalled carbon nanotubes (MWCNTs) was investigated to explore the possible application of MWCNTs for removal of both herbicides from contaminated water. The adsorption of diuron and dichlobenil on MWCNTs at pH 6 was nonlinear and fit the Polanyi-Manes model well. The adsorption of diuron and dichlobenil was closely correlated with specific surface areas and micropore volumes of MWCNTs. An increase in oxygen content of MWCNTs with same diameters and similar surface areas decreased the adsorption of diuron and dichlobenil, while increased the adsorption of lead. Micro-Fourier transform infrared spectroscopic study indicated that hydrogen bonding is a main mechanism responsible for the adsorption of diuron or dichlobenil onto MWCNTs-O. Oxygen containing groups, mainly carboxylic groups, significantly increased the adsorption of lead through the formations of outer-sphere and inner-sphere complexes, which are verified by X-ray absorption spectroscopic measurements. Oxygen containing groups and the presence of lead diminished the adsorption of diuron and dichlobenil. The suppression mechanisms of lead were ascribed to hydration and complexation of lead with carboxylic groups, which may occupy part of surface of MWCNTs-O. The large hydration shell of lead cations may intrude or shield hydrophobic and hydrophilic sites, resulting in a decreased adsorption of diuron and dichlobenil at the lead-complexed moieties. (C) 2011 Elsevier B.V. All rights reserved.
- Published
- 2011
26. Effects of metal cations on sorption-desorption of p-nitrophenol onto wheat ash
- Author
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Jing Zhang, Guangcai Chen, Xiao-quan Shan, Lirong Zheng, Yu-Sheng Wang, Yaning Xie, and Zhiguo Pei
- Subjects
Magnetic Resonance Spectroscopy ,Environmental Engineering ,Inorganic chemistry ,Nitrophenols ,Metal ,Nitrophenol ,chemistry.chemical_compound ,Adsorption ,Cations ,Metals, Heavy ,Desorption ,Spectroscopy, Fourier Transform Infrared ,Environmental Chemistry ,Qualitative inorganic analysis ,Fourier transform infrared spectroscopy ,Triticum ,General Environmental Science ,X-ray absorption spectroscopy ,Chemistry ,General Medicine ,Hydrogen-Ion Concentration ,Reference Standards ,Kinetics ,Zinc ,Biodegradation, Environmental ,X-Ray Absorption Spectroscopy ,Lead ,visual_art ,visual_art.visual_art_medium ,Absorption (chemistry) ,Copper - Abstract
The mutual effects of metal cations (Cu(2+), Pb(2+), Zn(2+), and Cd(2+)) and p-nitrophenol (NP) on their adsorption desorption behavior onto wheat ash were studied. Results suggested that Cu(2+), Pb(2+), and Zn(2+) diminished the adsorption and increased the desorption of NP remarkably, while Cd(2+) had no such effect. In contrast, NP diminished the adsorption of Cu(2+), Pb(2+), and Zn(2+) onto ash, however, this suppression effect depended on the initial concentrations of metal cations. NP had no effect on Cd2+ adsorption on ash. Fourier transform infrared (FT-IR) and X-ray absorption spectroscopic (XAS) studies suggested the following mechanisms responsible for the metal suppression effect on NP adsorption: (1) large hydrated Cu(2+), Pb(2+), and Zn(2+) shells occupied the surface of ash and prevent nonspecific adsorption of NP onto ash surface; (2) Cu(2+), Pb(2+), and Zn(2+) may block the micropores of ash, resulting in decreased adsorption of NP; (3) complexation of Cu(2+), Pb(2+), and Zn(2+) was likely via carboxyl, hydroxylic and phenolic groups of wheat ash and these same groups may also react with NP during adsorption. As a "soft acid", Cd(2+) is less efficient in the complexation of oxygen-containing acid groups than Cu(2+), Pb(2+), and Zn(2+). Thus, Cd(2+) had no effect on the adsorption of NP on wheat ash.
- Published
- 2011
27. Effects of humic acid and lipid on the sorption of phenanthrene on char
- Author
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Zhiguo Pei, Shuzhen Zhang, Rui-juan Li, Rixiang Huang, Ping Gong, Shahamat U. Khan, Bei Wen, Xiao-quan Shan, and Jing Fang
- Subjects
chemistry.chemical_classification ,Sorbent ,Soil Science ,Sorption ,Phenanthrene ,chemistry.chemical_compound ,chemistry ,Specific surface area ,Soil water ,Organic chemistry ,Humic acid ,Freundlich equation ,Char ,Nuclear chemistry - Abstract
The impact of two types of natural organic matters (NOM), humic acid (HA) and lipid, on char properties and sorption affinities for phenanthrene was studied. Char was coated with HA and lipid at a concentration of 0.060, 0.250 and 0.500 g/g char. HA, lipid, char and coated char were characterized and their sorption behaviors for phenanthrene were compared. Coating with NOM increased the polarity and aliphaticity, and reduced the specific surface area (SSA) of char, depending on the coated amount and the type of NOM. At the lower HA and lipid loading there was a strong attenuation of N(2)-assessible SSA. The SSA attenuation was less pronounced at larger HA and lipid loadings, which was most likely due to the preferential sorption at reactive sites and formation of clusters. The sorption isotherms of phenanthrene on char and coated char fitted Freundlich equation well, suggesting that all sorption isotherms were nonlinear, with N values in the range of 0.495-0.873. Coated char with HA and lipid decreased the organic carbon-normalized sorption coefficients K(Foc) and increased the N values. Lipid was more effective than HA in decreasing SSA. phenanthrene sorption capacity and sorption isotherm nonlinearity. The N values were correlated positively with the aliphaticity and negatively with pore volume of sorbents. The results of this investigation demonstrated that different NOM plays a different role in attenuating the SSA and sorption affinity of char for phenanthrene. (C) 2009 Elsevier B.V. All rights reserved.
- Published
- 2009
28. X-ray photoelectron spectroscopy and auger electron spectroscopy studies of Al-doped ZnO films
- Author
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Sun Chunshui, Youjun Yu, X. Wang, Mumei Chen, L.S. Wen, R.F. Huang, Zhiguo Pei, and Xuedong Bai
- Subjects
Auger electron spectroscopy ,Valence (chemistry) ,Materials science ,Doping ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Surfaces and Interfaces ,General Chemistry ,Zinc ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Metal ,Chemical state ,X-ray photoelectron spectroscopy ,chemistry ,visual_art ,visual_art.visual_art_medium ,Surface layer - Abstract
The chemical state of oxygen, aluminum and zinc in Al-doped ZnO (ZAO) films was investigated by X-ray photoelectron spectroscopy (XPS), as well as the transition zone of the film-to-substrate, by auger electron spectroscopy (AES). The results show that zinc remains mostly in the formal valence states of Zn2+. A distinct asymmetry in Al 2p(3/2) photoelectron peaks has been resolved into two components, one is metallic Al and the other is oxidized Al. The depth profile of the two components revealed that metallic Al mainly exists in the thin surface layer. The close inspection of Ols shows that Ols is composed of three components, centered at 530.15 +/- 0.15, 531.25 +/- 0.20 and 532.40 +/- 0.15 eV, respectively. AES reveals an abrupt transition zone between the ZAO and quartz substrate. (C) 2000 Elsevier Science B.V. All rights reserved.
- Published
- 2000
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