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Human induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs) have been believed to be a promising alternative for the stem cell transplantation therapy. The exosomes (Exo) from iMSCs play an important role in several kinds of life activities. The role of exosomes from iMSCs in severe acute pancreatitis (SAP) induced myocardial injury (MI) has not been investigated. The Exo were isolated from iMSCs through differential centrifugation method. The SAP rat model was established with 5% sodium taurocholate injection into the distal end of the bilepancreatic duct. RT-PCR and western blotting were used to measure related gene expression. Masson trichrome and Sirius Red stainings were used to evaluate MI injury. Cardiac function was detected through cardiac ultrasound.Exo promoted cell viability through activating Akt/nuclear factor E2 related factors 2 (Nrf2)/heme oxygenase 1 (HO-1) signaling pathway in vitro. Exo improved MI induced by SAP through activating Akt/Nrf2/HO-1 signaling pathway. Exo improved cardiac function, and suppressed oxidative status in the SAP model. Exo increased the expression of von Willebrand Factor (vWF) and vascular endothelial growth factor (VEGF) through activating Nrf2/HO-1 signaling pathway. Our data indicated that the Exo from iMSCs could improve MI caused by SAP through activating Nrf2/HO-1 axis. These findings firstly unfold the potential application of Exo from iMSCs in treating MI induced by SAP. Abbreviations: LVEF: Left ventricular ejection fraction; LVFS: left ventricular fractional shorten; LVDd: left ventricular end-diastolic diameter; LVDs: left ventricular end-systolic diameter; MI: Myocardial infarction; MSCs: Mesenchymal stem cells; iPSCs: Human-induced pluripotent stem cells; SAP: Severe acute pancreatitis; iMSCs: iPSCs derived VEGF: MSCs; vascular endothelial growth factor; Nrf2: Nuclear factor erythroid 2-related factor; RT-PCR: Real-time polymerase chain reaction; HE: Hematoxylin-eosin; MODS: Multiple organ dysfunction syndrome; PI3K: Phosphatidylinositol 3-kinase; SOD: Superoxide dismutase; FBS: Fetal bovine serum; ECL: Enhanced chemiluminescence; IHC: Immunohistochemistry.

Background: The extracellular vesicles (EVs) secreted by bone marrow mesenchymal stromal cells (MSCs) have the ability to improve Myocardial infarction (MI). Some microRNAs (miRNAs) including miR-497 and related target genes have been proved to be closely linked with heart diseases. However, EVs could regulate MI process through miR-497, and the mechanisms have not been fully reported. Methods: Ligation of left anterior descending artery was performed to established MI animals model. Hypoxia cell model was established through lowering the level of oxygen. The cell invasion, migration, and proliferation were measured using tanswell, wound heating, and MTT assays. HE, Masson trichrome, and Sirius Red staining were used to investigate the morphological changes. Results: Overexpression of miR-497 reversed the promotion of cell migration, invasion, and proliferation caused by EVs. The improvement of cardiac function induced by EVs could also be reversed by overexpression of miR-497. Direct binding site between Smad7 and miR-497 was identified. Knockdown of Smad7 reversed the improvement of cardiac function induced by EVs. Conclusions: We found that EVs isolated from MSCs might improve the cardiac injury caused by MI through targeting miR497/Smad7. This study provides novel potential therapeutic thought for the prevention and treatment of MI through targeting miR-497/Smad7.

A battery of agricultural straw derived biomass activated carbons supported LaOx modified MnOx (LaMn/BACs) was prepared by a facile impregnation method and then tested for simultaneous abatement of NO and Hg0. 15%LaMn/BAC manifested excellent removal efficiency of Hg0 (100%) and NO (86.7%) at 180 °C, which also exhibited splendid resistance to SO2 and H2O. The interaction between Hg0 removal and NO removal was explored; thereinto, Hg0 removal had no influence on NO removal, while NO removal preponderated over Hg0 removal. The inhibitory effect of NH3 was greater than the accelerative effect of NO and O2 on Hg0 removal. The physicochemical characterization of related samples was characterized by SEM, XRD, BET, H2-TPR, NH3-TPD, and XPS. After incorporating suitable LaOx into 15%Mn/BAC, the synergistic effect between LaOx and MnOx contributed to the improvement of BET surface area and total pore volume, the promotion of redox ability, surface active oxygen species, and acid sites, inhibiting the crystallization of MnOx. 15%LaMn/BAC has the best catalytic oxidation activity at low temperature. That might be answerable for superior performance and preferable tolerance to SO2 and H2O. The results indicated that 15%LaMn/BAC was a promising catalyst for simultaneous abatement of Hg0 and NO at low temperature.

This study synthesized nanocomposite catalysts via a modification of Re/Pd codoped carbon nanotubes (CNTs) with different concentrations of polydopamine (PDA), which were used for perchlorate (ClO4−) reduction. The loads, dispersion and reducibility of Re/Pd nanoparticles increased yet their particle sizes significantly decreased with the increase of PDA concentrations. The average diameter of Re/Pd codoped D2CNT (CNT modified by 2 mg/mL PDA) with a narrow size distribution was measured to be 2 nm. The ultrafine Re/Pd codoped D2CNT catalysts represented outstanding catalytic reduction activity for the conversion of ClO4− to Cl− with TOF of 17.34 h−1 under the room H2 atmospheric pressure, which was about 8 times than that of the unmodified catalysts. Furthermore, PDA modification minimized the dissociation of Re by chemical bonding between Re and CNTs carrier and maintained good stability of nanocomposite. This study inspires us to apply green bionic methods to enhance the catalytic reduction of perchlorate by changing the physical properties of Re/Pd nanoparticles.

Impregnating CuCl2 on AC (activated coke) support to synthesize xCuCl2/AC showed superior activity with higher 90% Hg0 removal efficiency at 80–140 °C, as well as a lower oxygen demand of 2% O2 for Hg0 removal. The acceleration on Hg0 removal was observed for NO and SO2. The BET, SEM, XRD, XPS, TPD, and FT-IR characterizations revealed that the larger surface area, sufficient active oxygen species and co-existence of Cu+ and Cu2+ may account for the efficient Hg0 removal. In addition, the low demand of gaseous O2 was contributed to higher content of active oxygen and formed active Cl. After adsorbing on Cu sites, Cl sites, and surface functional groups, the Hg0(ads) removal on xCuCl2/AC was proceeded through two ways. Part of Hg0(ads) was oxidized by active O and formed Hg0, and the other part of Hg0 combined with the active Cl, which was formed by the activation of lattice Cl with the aid of active O, and formed HgCl2. Besides, the Hg2+ detected in outlet gas through mercury speciation conversion and desorption peak of HgCl2 and Hg0 further proved it. As displayed in stability test and simulated industrial application test, CuCl2/AC has a promising industrial application prospect.

Active oxygen species (AOS) play an essential role in modulating the activity of activated coke (AC) based samples. In this paper, AC was endowed with abundant AOS by modifying with (NH

Rapid industrialization has inevitably led to serious air pollution problems, thus it is urgent to develop detection and treatment technologies for qualitative and quantitative analysis and efficient removal of harmful pollutants. Notably, the employment of functional nanomaterials, in sensing and photocatalytic technologies, is promising to achieve efficient in situ detection and removal of gaseous pollutants. Among them, carbon dots (CDs) have shown significant potential due to their superior properties, such as controllable structures, easy surface modification, adjustable energy band, and excellent electron-transfer capacities. Moreover, their environmentally friendly preparation and efficient capture of solar energy provide a green option for sustainably addressing environmental problems. Here, recent advances in the rational design of CDs-based sensors and photocatalysts are highlighted. An overview of their applications in air pollutants detection and photocatalytic removal is presented, especially the diverse sensing and photocatalytic mechanisms of CDs are discussed. Finally, the challenges and perspectives are also provided, emphasizing the importance of synthetic mechanism investigation and rational design of structures.

A series of CoOx modified MnOx/biomass activated carbons (CoMn/BACs) prepared by the ultrasound-assisted impregnation method were employed for the simultaneous removal of NO and Hg0 from simulated coal-fired flue gas for the first time. The physicochemical properties of such samples were characterized by XRD, BET, SEM, TEM, NH3-TPD, H2-TPR, FTIR, TG and XPS. 15%CoMn/BAC exhibited preferable performance for NO and Hg0 removal in a wide temperature range from 160 to 280 °C, and it yielded prominent NO removal efficiency (86.5%) and superior Hg0 removal efficiency (98.5%) at 240 °C. The interaction between NO removal and Hg0 removal lessened corresponding separate efficiency, the adverse effect of NH3 on Hg0 removal could not be offset by promotional influences of NO and O2. Compared with 15%Mn/BAC, the addition of CoOx with suitable amount into 15%CoMn/BAC could contribute to the synergistic effect between MnOx and CoOx, resulting in the increase of BET surface area and surface active oxygen species as well as Mn4+ concentration, the enhancement of redox ability and the strength or amount of surface acid sites, restraining the crystallization of MnOx, which might be responsible for the improvement of catalytic performance and resistance to SO2 and H2O. Additionally, the hydrophobic property of BAC further strengthened H2O tolerance. The results of stability and recyclability tests indicated that 15%CoMn/BAC possessed a promising application potential for NO and Hg0 simultaneous removal at low temperature.

MoO3-CeO2/cylindrical activated coke samples (MoCeY/AC) synthesized by an impregnation method were employed to investigate elemental mercury (Hg0) removal at 60–210 °C from simulated flue gas without HCl. MoCe0.5/AC with an optimal Mo/Ce molar ratio of 0.5 exhibited an excellent Hg0 removal efficiency (94.74%) at 120 °C, as well as good stability and prominent resistance to SO2 and H2O. The physicochemical property of the samples and the Hg0 removal mechanism were discussed by ICP-AES, SEM, EDX, BET, XRD, H2-TPR, XPS and Hg-TPD. The results of characterizations showed that MoCe0.5/AC possessed the special petal-like outer microstructure, large BET surface area, well-dispersed metal oxides and high reducibility, which was conducive for Hg0 removal. Furthermore, the synergistic effect between Mo6+ and Ce3+ was favorable to the high Hg0 removal performance by providing high valence Ce. According to the Hg-TPD tests, the chemisorption of Hg0 was a major approach for Hg0 removal, while physisorption and catalytic oxidation were just accounted for a tiny fraction. Moreover, the chemisorbed mercury could be validly distinguished into weakly-HgO, strongly-HgO, Oα-HgO and HgSO4 (when SO2 was added). Compared with raw AC, MoCe0.5/AC could enhance the Hg0 oxidation performance and produce Oα-HgO during the Hg0 removal process. In addition, the possible reason for the high SO2 tolerance of MoCe0.5/AC was examined: (i) the preferential combination between sulfate and MoO3 could protect CeO2 for Hg0 removal; (ii) SO2 could contribute to the formations of weakly-HgO and HgSO4. Finally, the regenerability of MoCe0.5/AC was also discussed.

The additive effect of different transition metal oxide M' (M' = Fe2O3, MnO2, and WO3) doping on V2O5/ZrO2–CeO2 (V/ZrCe) catalyst with reduced vanadium for simultaneous removal of NO and Hg0 was investigated. V/ZrCe doped with Fe2O3, MnO2, and WO3 and reduced vanadium were prepared by a wet-impregnation method and tested for their catalytic activity of simultaneous removal of NO and Hg0 in the temperature range of 100–400 °C. A combination of various analytical techniques including SEM, BET, XRD, H2-TPR and XPS were used to characterize the characteristics of catalysts. Results indicated that the introduction of M' could enhance the catalytic properties of the catalysts. V0.01Mn/ZrCe and V0.01Fe/ZrCe catalyst presented higher activities than the V0.03/ZrCe catalyst below 250 °C, while V0.01W/ZrCe catalyst exhibited a higher performance in the temperature range of 300–400 °C. The transition metal oxide M' species exist in a well dispersed state on V0.01/ZrCe catalysts. Doping the transition metal oxide M' on V0.01/ZrCe could affect the oxidation state of vanadium oxide and cerium oxide via the reaction of V4++Ce4+↔V5++Ce3+. Besides, the NO conversion was little impacted by Hg0, whereas SCR atmosphere has inhibited on Hg0 oxidation due to the strong competitive adsorption of NH3 with Hg0. The water and sulfur resistance performance decreased in the order of V0.01W/ZrCe> V0.01Fe/ZrCe > V0.01Mn/ZrCe.

A battery of agricultural straw derived biomass activated carbons supported LaOx modified MnOx (LaMn/BACs) was prepared by a facile impregnation method and then tested for the efficiency of simultaneous abatement of NO and Hg0. 15%LaMn/BAC manifested excellent removal efficiency of Hg0 (100%) and NO (86.7%) at 180 °C, which also exhibited splendid resistance to SO2 and H2O. The interaction between Hg0 removal and NO removal was explored, thereinto Hg0 removal had no influence on NO removal, while NO removal preponderated over Hg0 removal. The inhibitory effect of NH3 was greater than the accelerative effect of NO and O2 on Hg0 removal. The physicochemical characterization of related samples were characterized by SEM, XRD, BET, H2-TPR, NH3-TPD and XPS. After incorporating suitable LaOx into 15%Mn/BAC, the synergistic effect between LaOx and MnOx contributed to the improvement of BET surface area and total pore volume, the promotion of redox ability, surface active oxygen species and acid sites, inhibiting the crystallization of MnOx. 15%LaMn/BAC has the best catalytic oxidation activity at low temperature. That might be answerable for superior performance and preferable tolerance to SO2 and H2O. Finally, the principle of catalytic oxidation was also discussesed in this article.

A battery of agricultural straw derived biomass activated carbons supported LaO

MnxCoy/Zrz-AC prepared by impregnation method was investigated on the simultaneous removal of HCHO and Hg0. The samples were characterized by BET, SEM, XRD, H2 pulse chemisorption, H2-TPR, XPS, Hg-TPD and in-situ DRIFTS. Thereinto, the optimal Mn2/3Co8/Zr10-AC achieved 99.87% HCHO removal efficiency and 82.41% Hg0 removal efficiency at 240 °C, respectively. With increased surface area and pore volume, Zr-AC support facilitated higher dispersion of MnOx-CoOx. Moreover, the co-doping of MnOx-CoOx endowed the sample with more active oxygen species and higher reducibility, which further facilitated the removal of HCHO and Hg0. Chemisorption was proved to predominate in Hg0 removal, and oxidation also worked as Hg2+ was detected in outlet gas. Besides, HCHO predominated in the competition of active oxygen species, especially for lattice oxygen, thus suppressed the Hg0 removal. According to in-situ DRIFTS, HCHO removal proceeded as HCHOads → DOM → formate species → CO2 + H2O, and was boosted by active oxygen species. Furthermore, Mn2/3Co8/Zr10-AC was proved with excellent regeneration performance, indicating its potential in practical application.

A total of six conjugated polymers, namely PDBT-Th, PDBT-Th:Th, PDBT-2Th, PDBT-Th:2Th, PDBT-2Th:Th, and PDBT-2Th:2Th, consisting of dibenzothiophene, thiophene, and bithiophene were electrochemically synthesized. Their electrochemical and electrochromic properties were investigated in relation to the conjugation chain lengths of the thiophene units in the conjugated backbones. Density functional theory (DFT) calculations showed that longer conjugation lengths resulted in decreased HOMO-LUMO gaps in the polymers. The optical band gaps (Eg,opt) and electrochemical band gaps (Eg,cv) were decreased from PDBT-Th to PDBT-Th:Th, however, PDBT-Th:2Th, PDBT-2Th, PDBT-2Th:Th and PDBT-2Th:2Th displayed the similar band gaps. The conjugation length increments significantly improved the electrochemical stability of the conjugated polymers and exhibited reversible color changes due to the formation of polarons and bipolarons. The results suggest that the conjugated polymers prepared herein are promising candidates for fabricating flexible organic electrochromic devices.

The influence of nitrogen-containing composition during hydrothermal carbonization of biomass was investigated. Representative chemicals, protein, glycine, (NH4)2SO4, NH4Cl, and NaNO3, were used as nitrogen-containing species and glucose was used as model carbohydrate. The hydrochar yield, nitrogen distribution, and hydrochar properties were assessed. High ratio of glycine, (NH4)2SO4 and NH4Cl decreased hydrochar yield, conversely protein and NaNO3. The nitrogen content in hydrochar depended on the nitrogen-containing species and mass ratio in biomass, with 5 g glycine (260 °C and 2 h) having the highest value (9.20%). Especially, high (NH4)2SO4 and NH4Cl ratio increased of H/C and O/C of hydrochar at 180 °C, while protein and glycine mainly decreased O/C. However, all hydrochar had high degree of carbonization at 260 °C. Thermally unstable components appeared when protein and NH4Cl were added into the reaction mixture and more NH4Cl and NaNO3 decreased the maximum mass loss rate during pyrolysis.

This study explored the cooperative effects of hydrothermal or activators pretreatment and pyrolysis process on the chemical composition of bean dreg (BD)-derived carbon materials and its adsorption characteristics for methylene blue (MB) further. The results showed that hydrothermal assisted pyrolysis carbon with or without activator (HBK and HB) possess higher BET surface area than no hydrothermal assisted carbon (BKs and B, respectively). But surface area alone was not a critical factor contributing to MB adsorption, it also depends on strong electrostatic interaction and the hydrogen bonding interaction between N+ in MB combines with OH and COO− group of adsorbent surface by pH-dependent adsorption and pseudo-second-order model. Additionally, BK800 (pyrolysis at 800 °C) was identified as the most efficient adsorbent due to maximum adsorption capacity (434.78 mg g−1), and BDP (BD-derived polymer composite hydrogel), possessing excellent adsorption property and high reusability, made BK800 easier to separate from the regenerated dye solution.

In this study, the effects of different biochar catalysts on the quality of bio-oil derived from the co-pyrolysis of sewage sludge (SS) and rice husk (RH) are explored. Catalysts include SS biochar (SWC), RH biochar (RHC), mixed SS and RH biochar (SRC), and RH ash (RHA). The quality of bio-oil was evaluated based on the results of gas chromatography-mass spectrometry (GC–MS; including the contents of hydrocarbons and N-species), oxygen content, higher heating value, and pH. The GC–MS analysis results illustrated that N-species content in the bio-oil reduced with the addition of the biochar catalyst, while the hydrocarbons content increased from 15.51% for co-pyrolysis to 38.74–61.84% for different biochar catalysts at a catalytic temperature of 650 °C. RHC exhibited the best catalytic effect in terms of decreasing the content of N-species by 58.79% and increasing the content of hydrocarbons by nearly four times compared to co-pyrolysis. The higher heating value of bio-oil raised from 25.75 to 34.67 MJ/kg, while oxygen content decreased from 31.1 to 8.81 wt%, and the pH increased from 4.06 to 5.48. Moreover, the catalytic mechanism of catalytic co-pyrolysis over RHC, including the hydrocarbon generation pathway and nitrogen removal, is also discussed here. High specific surface area of RHC provides sufficient active sites (e.g. O-containing and N-containing functional groups) for the catalytic reaction of pyrolytic intermediates.

Phosphorus is a nutrient that is essential to nature and human life and has attracted attention because of its very limited reserves. Dwindling phosphorus reserves and soaring prices have made the recovery of phosphorus from waste biosolids even more urgent. Waste activated sludge, as the final destination of most of the phosphorus in human domestic and industrial water, has been considered as a reliable source of phosphorus recovery. The thermal treatment method of sewage sludge is currently a relatively environmentally friendly disposal method, which mainly includes incineration, pyrolysis and hydrothermal carbonization. This paper reviews the methods for the recovery of different forms of phosphorus (wet chemical, thermochemical and electrodialysis) from solid products obtained from different sludge thermal treatment methods (incinerated sewage sludge ash, pyrolysis of sewage sludge char and hydrochar) and the bioavailability of the recovered phosphorus products. Incineration of sewage sludge is currently the most established and effective method for recovering phosphorus from the thermal treatment products of sewage sludge. One of the wet chemical methods has been applied on a commercial scale and is expected to be further developed for future industrial applications. Pyrolysis and hydrothermal carbonation still have many research gaps in this field. Based on their principles and laboratory performance, both of them have the potential to recover phosphorus and should be further explored.

To provide insight into optimizing flue gas treatment, the reaction mechanism for simultaneous oxidation of NO and toluene with H2O using a A-site substituted La1-xCoxFeO3 (x=0-0.4) catalysts with three-dimensional porous structure was investigated. The results demonstrated that the partial substitution of La in porous LaFeO3 by Co can induce the structural distortion, promote the specific surface area, enhance more active site exposure and produce abundant reactive oxygen species, including lattice oxygen with higher mobility, more surface adsorbed oxygen as well as oxygen vacancies, which improved the catalytic activities remarkably. Besides, NO and toluene have mutual promoted effects in the reaction system. The inhibition effect of H2O on simultaneous oxidation of NO and toluene was confirmed in that H2O consumes the chemisorbed active oxygen atoms. Without H2O, absorbed NO reacts with chemisorbed oxygen to form NO2, and absorbed toluene is oxidized by lattice oxygen to generate intermediate species which finally completely oxidized into CO2 and H2O. With H2O, H2O react with chemisorbed oxygen to produce -OH species that occupied active sites for toluene adsorption. NO interacts with -OH species to form stable nitrate species, which offsets the inhibitive effect of H2O on NO oxidation due to the consumption of chemisorbed oxygen.

This study investigated the clean properties and combustion behavior of hydrochar from food waste (FW). The hydrochar was characterized by proximate analysis and HHVs, and the chemical forms were investigated by FTIR, XPS (Sulfur), and XANES (Chlorine). TG-FTIR was used to assess the combustion behaviors, and XRF was used to assess the fouling and slagging inclinations. Results showed that increasing temperature from 180 °C to 260 °C enhanced the removal of N, S, and Cl for hydrochar. Especially, aromatic-S and sulfate-S increased in contrast to sulfoxide-S, and more inorganic-S was produced in hydrochar; all samples had mainly inorganic-chlorine. Additionally, the release of HCl, SO2, and NO of hydrochar combustion were significantly reduced and the SI and FI index decreased to ranges of 0.18–0.16 and 0.32–0.17, respectively. However, hydrochar produced at temperature above 220 °C led increased NO emission possibly due to formation of more pyridine-N and quaternary-N.

This work had demonstrated a novel and high-efficiency perchlorate reduction particle electrode using benzalkonium chloride as dynamics strengthener and coupling with rhenium (Re) and palladium (Pd) nanoparticles (Re-Pd/BC). Perchlorate ions could be rapidly adsorbed in the presence of benzalkonium chloride, facilitating its subsequent reduction on the Re-Pd/BC particle electrode. On the basis of the characterization results and kinetics analysis, a synergistic effect of Re and Pd was observed, perchlorate could be efficiently reduced and completely converted into chlorine in optimized conditions (pH 3.0, anaerobic and current density 20 mA/cm2) and the reduction rate constant of Re-Pd/BC was 0.9451 L−1 gcat−1. The superfluous oxygen in solution could lead to Re-Pd/BC deactivation, and increased current density was beneficial of electro-reduction. The increased pH lead to decrease of reduction efficiency, and the coexisting anion of nitrate could be competed with perchlorate for reduction sites which lead to decrease of reduction rate. Based on the experimental results, it was found that the existing form of Re and Pd on the surface of Re-Pd/BC, the number of atomic H∗ and current density played an important role in perchlorate electro-reduction process.

A series of MnxFey/AC catalysts synthesized by impregnation method were investigated on the efficient and stable removal of HCHO in the fix-bed reactor. Extensive characterizations, BET, SEM, XRD, H2-TPR, XPS and FT-IR, were conducted to study the physicochemical properties, HCHO oxidation and surface reaction of catalysts. The optimal Mn0.75Fe6.02/AC showed enhanced HCHO removal efficiency of 98.30%, as well as excellent performance for simultaneous removal of HCHO (89.96%) and Hg0 (77.51%). NO and SO2 balanced in N2 would inhibit the removal of HCHO, while the addition of 6% O2 weakened the negative effect of SO2 and NO + 6% O2 facilitated the removal of HCHO. Besides, the slight promotion effect of water vapor was contributed to the regeneration of consumed −OH via the activation of surface oxygen by adsorbed H2O. Characterization results indicated that Mn0.75Fe6.02/AC possessed larger BET surface area, well-developed porosity and better dispersion of active components. Mn0.75Fe6.02/AC exhibited higher reducibility due to the synergistic effect between MnOx and FeOx, and the interaction between Mn-Fe oxides and AC support. At the same time, the oxygen-containing functional groups (C-O-, COO), abundant active surface oxygen and –OH facilitated both adsorption and oxidation of HCHO. Besides, the formate and carbonate intermediates formed on the surface of Mn0.75Fe6.02/AC in HCHO removal process, which could be further oxidized into CO2 and H2O. On the basis of above investigations, the mechanism of enhanced HCHO catalytic removal over MnxFey/AC was proposed.

Hydrothermal carbonization (HTC) is a thermochemical conversion technique which is attractive due to its ability to transform wet biomass into energy and chemicals without predrying. The solid product, known as hydrochar, has received attention because of its ability to prepare precursors of activated carbon in wastewater pollution remediation, soil remediation applications, solid fuels, and other carbonaceous materials. Besides the generally lignocellulose biomass used as sustainable feedstock, HTC has been applied to a wide range of derived waste, including sewage sludge, algae, and municipal solid waste to solve practical problems and generate desirable carbonaceous products. This review presented the critical hydrothermal parameters of HTC, including temperature, residence time, heating rate, reactant concentration, and aqueous quality. The chemical reaction mechanisms involved in the formation of hydrochar derived from single components and representative feedstock, lignocellulose, and sludge termed as N-free and N-rich biomass, were elucidated and summarized to better understand the hydrochar formation process. Specifically, hydrochar physicochemical characteristics such as surface chemistry and structure were investigated. Current knowledge gaps, and new perspectives with corresponding recommendations were provided to further exploit the great potential of the HTC technique and more practical applications for hydrochar in the future.

Hydrochar was produced from food waste under varying hydrothermal carbonization (HTC) conditions, and was pelletized using molasses and molasses/lime binders for fuel pellet production. The physico-chemical properties, density, mechanical properties, and water resistance, and combustion characteristics of the hydrochar pellets were investigated. The results indicated that molasses pellets and molasses/lime pellets exhibited increased compressive strength, density, and impact resistance due tothe “solid bridge” that formed from molasses recrystallization and agglomeration by lime. The hydrochar samples prepared at 230 °C and 260 °C, with long residence times of 8 h, showed excellent compressive strength and impact resistance index (IRI). Both molasses pellets and molasses/lime pellets exhibited slightly increased equilibrium moisture content (EMC), with the former showing a high water-resistance index (WRI) in the immersion test. Thermogravimetric analyses indicated that the molasses pellets had a lower ignition temperature and higher combustion interval than those of the molasses/lime pellets.

To rationally utilize agricultural wastes and expediently simultaneous control of elemental mercury (Hg0) and NO, a series of CoOx-CeO2 loaded maize straw derived biomass activated carbon (CoCe/BAC) samples were applied for simultaneous NO and Hg0 removal. These samples’ physicochemical characteristics were characterized by BET, SEM, XRD, NH3-TPD, H2-TPR, XPS and FTIR. 15%Co0.4Ce0.6/BAC yielded prominent Hg0 removal efficiency (96.8%) and superior NO removal efficiency (84.7%) at 230 °C. The separate or synchronous deactivation effects of 400 ppm SO2 and 5%H2O were detected. The interaction between NO removal and Hg0 removal was investigated, the results demonstrated that abundant Hg0 exhibited very slightly inhibitory effect on NO removal, and NH3 negatively affected Hg0 removal, whereas NO mildly boosted Hg0 removal in presence of O2. The characterization analyses indicated the excellent performance of 15%Co0.4Ce0.6/BAC could be ascribed to its better texture properties, lower crystallinity and stronger redox ability. Besides, a synergetic effect appeared between cobalt oxide and cerium oxide, resulting in generating more Ce3+ and Co3+ to induce more anionic defects and produce more active oxygen and oxygen vacancies. The removal mechanisms of NO and Hg0 were systematically investigated, and NO reduction reactions were mainly assigned to the Langmuir-Hinshlwood mechanism while both adsorption and Hg0 oxidation contributed to Hg0 removal. Meanwhile, Hg0 oxidation corresponded to the Mars-Masson mechanism prevailed gradually with the increase of reaction time.

The effect of CoOx addition on the performance and structure of V2O5/ZrO2–CeO2 catalyst for simultaneous removal of NO and Hg0 in simulated flue gas was investigated by various methods including SEM, BET, XRD, XPS, H2–TPR and FT–IR. It was found that the introduction of CoOx not only greatly enhanced the redox properties of catalysts, but also increased the catalytic performance for simultaneous removal of NO and Hg0. The CoOx–modified V2O5/ZrO2–CeO2 catalyst displayed excellent catalytic activity for NO conversion (89.6%) and Hg0 oxidation (88.9%) at 250 °C under SCR atmosphere. The synergistic effect among vanadium, cobalt, and the ZrCe support could induce oxygen vacancies formation and promote oxygen mobility via charge transfer. Besides, CoOx could assist vanadium species in rapidly changing the valence by the redox cycle of V5+ + Co2+ ↔ V4+ + Co3+. All the above features contribute to the excellent catalytic performance through CoOx addition.

To obtain a new low-cost catalyst that possesses well Hg0 removal activity in a broad temperature range, a series of Cu-Zrx/Cl-BC catalysts were synthesized with the application of bio-char which was activated by NH4Cl. CuO-ZrO2 as the active component largely improved Hg0 removal activity of the catalysts. The catalysts were characterized by SEM-EDX, BET, XRD, H2-TPR, XPS and FT-IR. When the CuO-ZrO2 loading value was 10%, Cu-Zr10/Cl-BC reached the best Hg0 removal efficiency (98.87%) at 120 °C and maintained over 80% until 240 °C. O2 was of benefit to Hg0 removal process especially at high temperature because it could regenerate the lattice oxygen which participated in the removal reaction. In addition, Hg0 removal was mainly determined by adsorption at low temperature and the function of oxidation increased at high temperature. The characterization results indicated that the superior performance of Cu-Zr10/Cl-BC might be ascribed to lower crystallinity, stronger redox ability and better texture properties which resulted from the interaction of CuO and ZrO2. The mechanism for Hg0 removal over Cu-Zr10/Cl-BC was also proposed on the basis of above studies.