181. 题目: The influence of nutrients on the composition and quantity of buried organic carbon in a eutrophic plateau lake, Southwest China
期刊: Science of The Total Environment
作者: Quanliang Jiang, Xikang Hou, Changchun Huang, Shuaidong Li, Xiaohua Ma, Hao Yang, Wenxin Wu, Zhili Chen, Tao Huang
摘要: The regulation of lacustrine organic carbon (OC) burial by nutrient is an outstanding knowledge gap in the current understanding of lake carbon cycles. In this study, we determined how nutrients quantitatively correspond with OC burial using the parallel factor analysis (PARAFAC) method in Dianchi Lake, southwest China. Factors were classified into three types according to their historical sedimentation characteristics: the background factor (BF), response factor (RF), and contingency factor (CF). The BF represented the original OC input combination in the lake and was insensitive to nutrient changes. The RF represented the OC input combination that was induced or promoted by nutrient changes in the lake. The CF represented short-term discontinuous factors in sedimentary history, which may be related to unique historical events. The results indicate that changes in the total nitrogen (TN) to total phosphorus (TP) ratio correlated with changes in the BF contribution; whereas the quantity of OC was mainly correlated with TN. The >90% of OC buried in sediment was quantitatively simulated by BF and RF; the driving effect of RF on OC burial was approximately 13 times higher than that of BF. It was observed that a 1 mg kg−1 increase in TN led to approximately 2.2 units increase in RF contribution in Dianchi Lake, while the BF was insensitive to changes in TN. Thus, changes in lake nutrients may effectively change the composition and quantity of OC buried in lake sediment.
182. 题目: Insights into the role of biochar on the acidogenic process and microbial pathways in a granular sulfate-reducing up-flow sludge bed reactor
期刊: Bioresource Technology
作者: Xiaohui Wu, Yawu Zhou, Muxiang Liang, Xiejuan Lu, Guanghao Chen, Feixiang Zan
摘要: In this study, the effect of biochar on sulfate reduction and anaerobic acidogenic process was explored in a granular sulfate-reducing up-flow sludge bed (GSRUSB) reactor in both long-term operation and batch tests. Both bioreactors had a high sulfate reduction efficiency of over 95% during the long-term operation, while the reactor with biochar addition showed higher sulfate reduction efficiency and stronger robustness against volatile fatty acid (VFAs) accumulation with a higher organic loading and sulfate loading rate. Batch tests showed that adding biochar significantly lessened the lag phase of the sulfate-reducing process, accelerated the adaption of acidogens, and facilitated both production and utilization of volatile fatty acids. The microbial pathways proved that biochar could regulate the acidification fermentation pathway and facilitate the enrichment of assimilative desulfurization bacteria. Overall, this study revealed that the acidogenic sulfate-reducing metabolic pathway could be enhanced by biochar, offering a potential application for effective sulfate-laden wastewater treatment.
183. 题目: Biological carbon pump sequestration efficiency in the North Atlantic: A leaky or a long‐term sink?
期刊: Global Biogeochemical Cycles
作者: Chelsey A. Baker, Adrian P. Martin, Andrew Yool, Ekaterina Popova
摘要: The North Atlantic Ocean is a key region for carbon sequestration by the biological carbon pump (BCP). The quantity of organic carbon exported from the surface, the region and depth at which it is remineralized, and the subsequent timescale of ventilation (return of the remineralized carbon back into contact with the atmosphere), control the magnitude of BCP sequestration. Carbon stored in the ocean for >100 years is assumed to be sequestered for climate-relevant timescales. We apply Lagrangian tracking to an ocean circulation and marine biogeochemistry model to determine the fate of North Atlantic organic carbon export. Organic carbon assumed to undergo remineralization at each of three vertical horizons (500m, 1000m, and 2000m) is tracked to determine how much remains out of contact with the atmosphere for 100 years. The fraction that remains below the mixed layer for 100 years is defined as the sequestration efficiency of remineralized exported carbon (REC). For exported carbon remineralized at the 500m, 1000m and 2000m horizons, the sequestration efficiency is 28%, 66% and 94%, respectively. Calculating the amount of carbon sequestered using depths ≤1000m, and not accounting for downstream ventilation, overestimates 100-year carbon sequestration by at least 39%. This work has implications for the accuracy of future carbon sequestration estimates, which may be overstated, and for carbon management strategies (e.g. oceanic carbon dioxide removal and Blue Carbon schemes) that require long-term sequestration to be successful.
184. 题目: Terrigenous organic carbon drives methane dynamics in cascade reservoirs in the upper Yangtze China
期刊: Water Research
作者: Yuanyuan Zhang, Youheng Su, Zhe Li, Shuhui Guo, Lunhui Lu, Bin Zhang, Yu Qin
摘要: Methane (CH4) emissions from freshwaters to the atmosphere have a profound impact on global atmospheric greenhouse gas (GHG) concentrations. Anthropogenic footprints such as dam construction and reservoir operation significantly changed the fate and transport of CH4 in freshwaters. The source of particulate organic carbon (POC) in reservoirs is a critical factor controlling CH4 production and emissions. However, little is known of how reservoir operation mediates the transport of POC and regulates CH4 accumulation in cascade hydroelectric reservoirs. Here, spatial and temporal variations in POC and CH4 were explored in the Xiluodu (XLD) and Xiangjiaba (XJB) reservoirs which are deep valley cascade reservoirs located in the main channel of the upper Yangtze River. Based on the δ13C-POC and N/C mole ratio of particulate organic matter, the results of multi-endmember stable isotope mixing models by a Bayesian model showed that terrigenous POC and autochthonous POC accounted for approximately 55% ± 18% and 43% ± 19% (SD, n = 179) of POC, respectively. Together with other hydrological and environmental parameters, we found that the input of terrigenous POC was dominantly influenced by water level variations and flow regulation due to reservoir operation. The cumulative effect of POC caused by cascade dams was not apparent. Terrigenous POC were more likely to drive CH4 accumulation in our study. Evident low level of CH4 in both reservoirs were likely affected by low sedimentation of POC and microbial CH4 oxidation. We hope our study could provide a conceptual framework for further modeling of CH4 dynamics in cascade reservoirs.
185. 题目: Microbial metabolism changes molecular compositions of riverine dissolved organic matter as regulated by temperature
期刊: Environmental Pollution
作者: Gang Tang, Xing Zheng, Shiwen Hu, Binrui Li, Shuling Chen, Tong Liu, Bowei Zhang, Chongxuan Liu
摘要: This study investigated the control of dissolved organic matter (DOM) molecular compositions by microbial community shifts under temperature regulation (range from 5 to 35 °C), using riverine DOM and in situ microorganisms as examples. The functioning of different microbial metabolisms, including the utilization and generation processes, was comprehensively analyzed. Though the overall quantity of DOM was less temperature-affected, more molecules were identified at moderate temperatures (e.g., 15 and 25 °C) and their accumulated mass peak intensities increased with the temperature. The results were ascribed to 1) the microbial production of macromolecular (m/z > 600) CHO, CHON, and CHONS species was stimulated at higher temperatures; 2) the microbial consumed more DOM molecules at both higher and lower temperatures; and 3) the simultaneously decreased utilization and increased generation of recalcitrant CHO and CHON molecules with m/z < 600 at higher temperatures. The strong correlations among the temperature, community structures, and DOM chemodiversity suggested the temperature promoted the community evenness to increase the DOM generation. In addition, the higher temperature decreased the abundance of microorganisms that utilized more recalcitrant molecules and produced fewer new molecules (e.g., Proteobacteria, Acinetobacter, and Erythrobacter) while increased others that functioned the opposite (e.g., Verrucomicrobia, Bacteroidetes, and Flavobacterium) to increase the DOM production. The constructed temperature-community-DOM chemistry relationship deepened the molecular-level understanding of DOM variations and provided implications for the warming future.
186. 题目: Comparative study on the relative significance of low-/high-condensation aromatic moieties in biochar to organic contaminant sorption
期刊: Ecotoxicology and Environmental Safety
作者: Zhaofeng Chang, Luping Tian, Jun Zhang, Dandan Zhou
摘要: Aromatic moieties of biochar are considered as key components for immobilizing hydrophobic organic contaminants in the environment. However, the relative importance of different aromatic moieties such as low-/high-condensation components in sorption has not been comprehensively investigated. In this study, biochar was produced from flue-cured tobacco straw (TB) and pine wood sawdust (WB) at various pyrolysis temperatures (200–600 °C). Aromatic moieties were characterized via elemental analysis, Fourier transform infrared spectroscopy, Raman spectroscopy, and benzene polycarboxylic acid molecular markers (BPCAs). The significance of different aromatic moieties in the sorption of phenanthrene (PHE) and bisphenol A (BPA) was assessed based on the individual BPCA patterns. The results indicated that aromaticity and aromatic moiety contents increased with increasing pyrolysis temperature. Biochar at 200 °C produced lower mellitic acid (B6CA) contents (18.7–27.9%) than the others. When the pyrolysis temperature was increased to 600 °C, the B6CA contents representing high-condensation aromatic moieties accounted for 55.4–60.9% of all the aromatic moieties. The unitary linear regressions between the individual BPCA distribution patterns and the n values and log Kd suggested that the high-condensation aromatic moieties played a more significant role than the low-condensation aromatic moieties (represented by B3CA–B5CA) in facilitating sorption nonlinearity (for PHE and BPA) and sorption capacity (for PHE). The elevated sorption of PHE can be attributed to the increased specific surface area and hydrophobicity of the newly formed aromatic moieties. Hydrogen bonds and π–π electron–donor–acceptor were the main mechanisms of BPA sorption. Because the WB biochar contained more aromatic moieties and more O-containing groups on the surface of the TB biochar, the WB exhibited a higher sorption for PHE; however, slightly elevated sorption was observed on the TB for BPA. This research may provide a new perspective in understanding the behavior of biochar aromatic moieties in sorption of organic contaminants.
187. 题目: Removal mechanisms of Cd from water and soil using Fe–Mn oxides modified biochar
期刊: Environmental Research
作者: Tingting Yang, Yingming Xu, Qingqing Huang, Yuebing Sun, Xuefeng Liang, Lin Wang
摘要: The development of remediation materials simultaneously suitable for Cd-contaminated water and soil is of great significance. In this study, the functional biochar (FM-RBC and FM-DBC) was prepared using branch and durian shell biochar (RBC and DBC, respectively) with iron-manganese oxide (Fe–Mn oxide) modification. The behaviors and mechanisms of Cd adsorption and stabilization in water and alkaline soil treated with FM-RBC and FM-DBC were explored. The results showed that the adsorption capacities of RBC and DBC for Cd had increased by 40–80 mg/g after the Fe–Mn oxide modification. The Cd adsorption was conformed to pseudo-second-order kinetic and the Langmuir isothermal models. After 35 days of soil cultivation, the maximum reduction rate of DTPA-Cd occurred in 3% FM-DBC treatments (37.73%), followed by in 3% FM-RBC (30.08%), all of which were significantly higher than that observed in 3% BC treatments (12.55–18.91%). Notably, the FM-RBC and FM-DBC treatments promoted the conversion of the exchangeable to the carbonate-bound and Fe/Mn oxyhydroxide fractions of Cd. The XRD, FTIR, and XPS analyses demonstrated that the loading amount of Fe–Mn oxide was positively correlated with the oxygen-containing functional group of biochar. CdO, Cd2Mn3O8 and CdCO3 were loaded on the FM-BC, indicating the existence of two main adsorption mechanisms: (1) the complexation with M-O (M: Fe, Mn) and acid oxygen-containing functional groups, (2) the precipitation with carbonate of Cd. In this work, we prepared two functional biochar that rapidly removes Cd from water and effectively fixes Cd in alkaline soil, thus, debasing the risk of Cd entry into the food chain.
188. 题目: Effect of disinfection on the photoreactivity of effluent organic matter and photodegradation of organic contaminants
期刊: Water Research
作者: Dong Wan, Jie Wang, Tong Chen, Weiming Xiang, Steplinpaulselvin Selvinsimpson, Yong Chen
摘要: Chlorine, UV254, and ozone are three typical processes commonly used for wastewater disinfection, which could change the photoreactivity of dissolved organic matter (DOM) in effluents of wastewater treatment plants (WWTPs). The photoinduced reactive species (RS) from DOM, primarily including the excited triplet state of DOM (3DOM*), singlet oxygen (1O2), and hydroxyl radical (•OH), play important roles in the attenuation of contaminants. However, the effect of disinfection processes on the photosensitized degradation of contaminants is poorly understood. This paper presents the first evidence that 3DOM*, 1O2, and •OH interaction with three typical contaminants (diphenhydramine, cimetidine, and N,N-diethyl-m-toluamide (DEET)) was largely impacted by DOM after disinfection. The results of electron spin resonance (ESR) spectrometry and laser flash photolysis (LFP) experiments demonstrated that the chlorination increased the formation rate of 3DOM* and 1O2, while UV254 irradiation and ozonation decreased the formation rate of these RS. All these three disinfection processes promoted the photoproduction of •OH and increased the photodegradation rate constants (kobs) of DEET by 26−361%. The kobs of diphenhydramine, cimetidine, and DEET correlated positively with the formation rate of 3DOM*, 1O2, and •OH, respectively. The bimolecular reaction rate constant of 3DOM* with diphenhydramine increased by ∼41% after chlorination. These findings suggest that disinfection processes altered the photogeneration of RS from DOM, which significantly impacts the fate of trace pollutants in aquatic environments.
189. 题目: Occurrence of dissolved black carbon in source water and disinfection byproducts formation during chlorination
期刊: Journal of Hazardous Materials
作者: Haoran Chen, Junjie Wang, Xiating Zhao, Yuting Wang, Zhijun Huang, Tingting Gong, Qiming Xian
摘要: Dissolved black carbon (DBC), the water-soluble component of black carbon, which is formed by incomplete combustion of fossil fuels or biochar, takes up about 10% of dissolved organic matter (DOM) in river water. However, the distribution of DBC in water environment especially in source water is not clear and as an important component of DOM, whether DBC can produce disinfection byproducts (DBPs) like other DOM during disinfection remains unknown. In this study, the DBC concentrations in seventeen source water samples from East China were measured. The concentrations of DBC in the source water samples ranged from 60-270μg/L, which were positively correlated with UV254 absorbance and chemical oxygen demand. The levels of DBC in wet season were higher than that in dry season. The average concentrations of DBC in different types of source water samples followed the order of reservoir > canal > lake > river. DBC could only be removed by 20% during the simulated coagulation, and further generate different categories of DBPs during chlorination, among which the concentrations of haloacetic acids (HAA) were the highest. The results indicated that DBC widely distributes in source water and is an important precursor of HAAs and THMs during chlorination.
190. 题目: Biochar immobilized bacteria enhances nitrogen removal capability of tidal flow constructed wetlands
期刊: Science of The Total Environment
作者: Lin Zhao, Guiping Fu, Weicheng Pang, Jia Tang, Zhipeng Guo, Zhangli Hu
摘要: To improve the nitrogen removal (NR) capability of tidal flow constructed wetlands (TFCWs) for treatment of saline wastewater, biochar, produced from Cyperus alternifolius, was used to adsorb and immobilize a salt tolerant aerobic denitrifying bacteria (Zobellella sp. A63), and then was added as a substrate into the systems. Under low (2:1) or high (6:1) C/N ratio, the removal of NO3−–N and total nitrogen (TN) in the biochar immobilized bacteria (BIB) dosing system (TFCW3) was significantly higher (q < 0.05) than that in the untreated system (TFCW1) and the biochar dosing system (TFCW2). At low C/N ratio, the removal rates of NO3−–N, TN and chemical oxygen demand (COD) of TFCW3 were 68.2%, 72.6% and 82.5%, respectively, 15–20% higher than TFCW1 and 5–10% higher than TFCW2. When C/N was further increased to 6, the pollutant removal efficiency of each system was greatly improved, but the removal rate of TFCW3 for NO3−–N/TN was still nearly 10% and 5% higher than TFCW1 and TFCW2, respectively. Microbial community analysis showed that aerobic denitrifying bacteria, sulfate reducing bacteria and sulfur-driven denitrifiers (DNSOB) played the most important role of NR in TFCWs. Moreover, biochar bacterial agent significantly increased the abundances of genes involved in NR. The total copy numbers of bacterial 16S rRNA, nirS, nirK, drsA and drsB genes in the TFCW3 were 1.1- to 3.76-fold higher than those in the TFCW1; Especially at low C/N ratio, the copy number of drsA and drsB in the upper layer of TFCW3 were 85.5 and 455 times that of TFCW1, respectively. Thus, BIB provide a more feasible and effective amendment for constructed wetlands to improve the N removal of the saline wastewater by enhancing the microbial NR capacity mainly via aerobic and sulfur autotrophic denitrification.
191. 题目: Biochar and biochar-polylactic acid composite enhance biodegradation of hexachlorobenzene in soil by altering microbial community
期刊: Applied Soil Ecology
作者: Jianling Fan, Cuiying Liu, Dengwei Guo, Lu Han, Chuanhong Zhang, Hao Jin
摘要: It is of great scientific and practical importance to explore the mechanisms of accelerated degradation of hexachlorobenzene (HCB) in soil. However, the response of microbial community composition and structure, and their links to anaerobic reductive dechlorination in paddy soils remains unclear yet. We examined impacts of biochar and biochar-polylactic acid composite addition on the diversity, composition, and structure of soil prokaryotic community and their different contribution to HCB anaerobic dechlorination. The results showed that both biochar and biochar-polylactic acid composite addition could promote HCB dechlorination in paddy soils. Soil prokaryotic community richness and diversity were not significantly impacted by biochar but were remarkably affected by biochar-polylactic acid composite amendment. Random forest analysis and structural equation models indicated that the relative abundance of indicator taxa, soil Eh, and Fe2+ content best explained (p < 0.01) the HCB dechlorination with biochar addition, while soil Eh, Fe2+ content, and microbial diversity were the most important predictors of HCB dechlorination with biochar-polylactic acid composite addition. Together, our findings suggest that biochar amendment promoted anaerobic dechlorination of HCB in paddy soils by increasing the relative abundance of specific bacterial genera, while biochar-polylactic acid composite promoted HCB dechlorination by enhancing microbial community diversity. Therefore, biochar and biochar-polylactic acid composite showed distinct effect on the composition and diversity of soil prokaryotic community and different contribution to HCB dechlorination. Overall, our results suggested that biochar-polylactic acid composite could be used as soil remediation material to efficiently accelerate dechlorination of HCB.
192. 题目: Radical and non-radical cooperative degradation in metal-free electro-Fenton based on nitrogen self-doped biochar
期刊: Journal of Hazardous Materials
作者: Ting Zhang, Lu Sun, Xiaohong Sun, Heng Dong, Han Yu, Hongbing Yu
摘要: To achieve sustainable metal-free electron-Fenton, N self-doped biochar air-cathode (BCAC) was prepared by pyrolyzing coffee residues. During the pyrolysis process, the endogenous N transformed from edge-doping to graphite-doping. Particularly, N vacancies started to evolve when the peak temperature exceeded 700 °C. A high Tetracycline removal rate of 70.42% was obtained on the BCAC at the current density of 4mAcm-2. Quenching tests incorporated with ESR spectroscopy were adopted to identify the specific oxidants produced on the cathode. The results showed that •OH (37.36%), •O2- (29.67%) and 1O2 (24.17%) played comparable role in the tetracycline removal, suggesting the coexist of radical and non-radical oxidants in our electro-Fenton system. According to the structure characterization and the DFT calculation, graphitic N was suggested as the critical site for H2O2 generation, and both graphitic N and pyridinic N were electroactive sites for H2O2 activation to •OH. Graphitic N and N vacancies with stronger capabilities in O2 adsorption and electron-trapping were proposed as the electroactive sites for 1O2 and •O2- formation. This work predicts a novel electro-Fenton process with cooperative radical and non-radical degradation on N self-doped carbonaceous catalysts at a mild condition, which is extremely meaningful for boosting sustainable electro-Fenton technology.
193. 题目: Roles of humic substances redox activity on environmental remediation
期刊: Journal of Hazardous Materials
作者: Xiong-Xin Peng, Shuang Gai, Kui Cheng, Fan Yang
摘要: Humic substances (HS) as representative natural organic matters and the most common organic compounds existing in the environment, has been applied to the treatment and remediation of environmental pollution. This review systematically introduces and summarizes the redox activity of HS for the remediation of environmental pollutants. For inorganic pollutants (such as silver, chromium, mercury, and arsenic), the redox reaction of HS can reduce their toxicity and mobilization, thereby reducing the harm of these pollutants to the environment. The concentration and chemical composition of HS, environmental pH, ionic strength, and competing components affect the degree and rate of redox reactions between inorganic pollutants and HS significantly. With regards to organic pollutants, HS has photocatalytic activity and produces a large number of reactive oxygen species (ROS) under the light which reacts with organic pollutants to accelerate the degradation of organic pollutants. Under the affection of HS, the redox of Fe(III) and Fe(II) can enhance the efficiency of Fenton-like reaction to degrade organic pollutants. Finally, the research direction of HS redox remediation of environmental pollution is prospected.
194. 题目: Two-step ball milling-assisted synthesis of N-doped biochar loaded with ferrous sulfide for enhanced adsorptive removal of Cr(Ⅵ) and tetracycline from water
期刊: Environmental Pollution
作者: Jianhua Qu, Weihang Zhang, Fuxuan Bi, Shaojuan Yan, Xuemei Miao, Bo Zhang, Yifan Wang, Chengjun Ge, Ying Zhang
摘要: Nitrogen-doped biochar loaded with FeS (FeS@NBCBM) was synthesized by two-step ball milling processes. Characterization results revealed that N-doping process successfully introduced pyridinic, pyrrolic, and graphitic N structures, and FeS was subsequently embedded in N-doped biochar (NBCBM). The resultant FeS@NBCBM presented predominant adsorption capacity for Cr(VI) (194.69 mg/g) and tetracycline (TC, 371.29 mg/g) compared with BC (27.28 and 37.89 mg/g) and NBCBM (71.26 and 81.26 mg/g). In addition, the Cr(VI)/TC elimination process by FeS@NBCBM was basically stable with multiple co-existing ions with slight decrease on adsorption performance after three desorption-regeneration cycles. Most importantly, FeS@NBCBM was found to achieve Cr(VI) elimination not only by electrostatic attraction, ion exchange and complexation, but also by electrons-triggered reduction provided by different species of N, Fe2+ as well as S(Ⅱ). Meantime, pore filling, hydrogen bonding, and π-π stacking interactions were demonstrated to contribute to TC adsorption. These results suggested the co-modification of N-doping and FeS loading by ball milling as an innovative decorating method for biochar to adsorptive purification of Cr(VI) and TC-contaminated water.
195. 题目: Plasma regulates active sites on biochar to boost peroxomonosulfate activation for phenol degradation
期刊: Journal of Environmental Chemical Engineering
作者: Xianjie Liu, Jiabin Zhou, Dan Liu
摘要: Metal-free biochar (BC), as a green catalyst, has exhibited superior engineering applications potential in wastewater purification. However, the performance of the pristine BC for peroxymonosulfate (PMS) activation is unsatisfactory. To this end, this work innovatively employed the plasma modification of BC and thus improving its catalytic activity. The plasma-modified BC (0.2g/L) was used to thoroughly degrade phenol (10mg/L) at 100min, and its oxidation rate constant (0.0483min-1) and TOC removal rate (46%) are 18-fold and 2.1-fold that of pristine BC, respectively. Significantly, a quantitative structure-activity relationship (QSAR) was established in the PMS/BC system. It was confirmed that the ketone carbonyl content and the degree of carbon structural defects were the critical factors in the biochar for phenol degradation. Theoretical calculations further verified that the single-vacancy defect and ketone carbonyl (C=O) in biochar is the essential reaction sites. These sites give rise to the unequal distribution of electrons in the carbon structure. Meanwhile, the potential difference between the HOMO of BC and the HUMO of PMS drives the electron transfer to activate PMS. Herein, we provide an effective method to regulate the active sites, thereby further promoting the environmental application of biomass-derived carbon materials.
196. 题目: Renewable biochar derived from mixed sewage sludge and pine sawdust for carbon dioxide capture
期刊: Environmental Pollution
作者: Kai Li, Xiaojun Niu, Dongqing Zhang, Huafang Guo, Xifen Zhu, Hua Yin, Zhang Lin, Mingli Fu
摘要: Carbon dioxide (CO2) is the main anthropogenic greenhouse gas contributing to global warming. In this study, a series of KOH-modified biochars derived from feedstock mixtures (i.e., S3W7 biomass consisting of 70% pine sawdust and 30% sewage sludge; S5W5 biomass consisting of 50% pine sawdust and 50% sewage sludge) at different temperature (i.e., 600–800 °C) were prepared for evaluating CO2 adsorption performance. The KOH-activated biochars prepared with S3W7 biomass displayed larger surface areas and micropore volumes compared to those of S5W5 biochars. In particular, the highest CO2 adsorption capacity (177.1 mg/g) was observed on S3W7 biomass at 700 °C (S3W7–700K), due to the largest surface area (2623 m2/g) and the highest micropore volume (0.68 cm3/g). Furthermore, surface functional groups, hydrophobicity, and aromaticity of biochar and presence of hetero atoms (N) also were actively involved in CO2 adsorption of biochar. In addition, in situ DRIFTS analysis advanced current understanding for the chemical sorption mechanisms by identifying the transformation composites of CO2 on biochars, and characterizing the weakly adsorbed and newly formed mineral species (e.g., carbonates) during the CO2 sorption process. This study may provide an insight into the research of CO2 capture by identifying physical and chemical adsorption, and expand the effective utilization of natural biomass-based biochar for mitigation greenhouse gas emission.
197. 题目: Impact of divalent cations on lysozyme-induced solubilisation of waste-activated sludge: Perspectives of extracellular polymeric substances and surface electronegativity
作者: Junguo He, Pengfei Zhang, Xiang Zou, Yijie Zhong, Xinlei Pan, Heliang Pang, Jie Zhang, Xinxin Cui, Xuewei Wu, Biqing Li, Xia Tang, Xiannian Xiao
摘要: Lysozyme hydrolysis can accelerate waste-activated sludge (WAS) solubilisation, which can significantly shorten the process and promote the efficiency of anaerobic digestion. This study investigated the impact of divalent cations on lysozyme-induced solubilisation of WAS. The performance of lysozyme pretreatment was dramatically inhibited by Mg2+ and Ca2+. Compared to the control group, the amount of net SCOD, protein, and polysaccharides released to the supernatant were reduced by 36.6%, 44.7%, and 35.8%, respectively, in the presence of divalent cations. The extracellular polymeric substance (EPS) matrix became tightly bound, resulting in fewer proteins and polysaccharides being extracted from loosely-bound EPS (LB-EPS) with divalent cations, which was detrimental to the solubilisation of WAS. Divalent cations decreased the surface electronegativity of sludge particles and prolonged the adsorption of lysozymes by sludge flocs. More than 16.6% of total lysozymes remained in the liquid phase of WAS after 240 min Mg2+ and Ca2+ strengthened the binding among proteins and polysaccharides and promoted the intermolecular cross-linking of polysaccharides. The EPS matrix formed a dense spatial reticular structure that blocked the transfer of lysozymes from the EPS matrix to the pellet. As a result, the lysozymes accumulated in LB-EPS rather than hydrolysing the microorganism's cell wall. This study provides a new perspective on the restriction of WAS pretreatment with lysozymes and optimises the method of lysozyme-induced solubilisation of WAS.
198. 题目: Copyrolysis of Recycled Plastics and Biomass Reduces Biochar Bioavailable Silicon Production and Cadmium Phytotoxicity
期刊: ACS ES&T Engineering
作者: Litao Lin, Jiewen Luo, Qian Wang, Chao Jia, Shicheng Zhang, Xinchao Wei, Liang Wang, Shichuan Su, Xiangdong Zhu
摘要: Plastic-biomass copyrolysis is often used to recycle solid waste and obtain highly aromatic biochar, which can be used for pollutant adsorption. Bioavailable silicon in derived biochar is of great importance to stabilize and alleviate phytotoxicity of soil heavy metal. However, the exact role of plastic-biomass copyrolysis in biochar bioavailable silicon is not well understood. Copyrolysis of different plastics with silicon-containing biomass (such as rice straw) was carried to investigate transformation of silicon in biochar. It was found that biomass inherent alkaline carbonate (such as K2CO3) reacted with silicon to form K2SiO3, and its dissolution led to a high amount of bioavailable silicon in biochar. In the meantime, copyrolysis of heteroatom-containing plastics (such as polyvinyl chloride and triphenyl phosphate) with biomass inhibited K2SiO3 formation in a dose-dependent manner, which mainly involves the capture of biomass inherent K2CO3 to drive new biochar mineral (KCl and K3PO4) formation. Lack of K2SiO3 formation reduced the bioavailable silicon content of copyrolyzed biochar and simultaneously decreased the Brunauer–Emmett–Teller surface area because of consumption of K2CO3 (porogen). It was also revealed that plastic-biomass copyrolysis reduced Cd stabilization capacity of its derived biochar. Moreover, according to wheat seed germination experiments, copyrolyzed biochar exhibited weak capacity to reduce Cd phytotoxicity. These crucial findings highlight the complex nature of using copyrolyzed biochar.
199. 题目: Reduced Black Carbon Concentrations following a Three-Year Stepped-Wedge Randomized Trial of the Wood-Burning Justa Cookstove in Rural Honduras
期刊: Environmental Science & Technology Letters
作者: Bonnie N. Young, Nicholas Good, Jennifer L. Peel, Megan L. Benka-Coker, Joshua P. Keller, Sarah Rajkumar, Ethan S. Walker, John Volckens, Christian L’Orange, Casey Quinn, Sebastian Africano, Anibal B. Osorto Pinel, Maggie L. Clark
摘要: Household air pollution from cooking-related biomass combustion remains a leading risk factor for global health. Black carbon (BC) is an important component of particulate matter (PM) in household air pollution. We evaluated the impact of the engineered, wood-burning Justa stove intervention on BC concentrations. We conducted a three-year stepped-wedge randomized controlled trial with six repeated visits among 230 female primary cooks in rural Honduras. Participants used traditional stoves at baseline and were randomized to receive the Justa after visit 2 or after visit 4. During each visit, we measured 24 h gravimetric personal and kitchen fine PM (PM2.5) concentrations and estimated BC mass concentrations (Sootscan Transmissometer). We conducted intent-to-treat analyses using linear mixed models with natural log-transformed 24 h personal and kitchen BC. BC concentrations were reduced for households assigned to the Justa versus traditional stoves, e.g., personal BC geometric mean (geometric standard deviation) of 3.6 μg/m3 (6.4) versus 11.5 μg/m3 (4.6), respectively. Following the intervention, we observed 53% [95% confidence interval (CI) of 35–65%] lower geometric mean personal BC concentrations and 76% (95% CI of 66–83%) lower geometric mean kitchen BC concentrations. The Justa stove intervention substantially reduced BC concentrations, mitigating household air pollution and potentially benefiting human and climate health.
200. 题目: Characterization of Montmorillonite–Biochar Composite and Its Application in the Removal of Atrazine in Aqueous Solution and Soil
期刊: Frontiers in Environmental Science
作者: Pingping Wang, Marianne Stenrød, Liang Wang, Shankui Yuan, Liangang Mao, Lizhen Zhu, Lan Zhang, Yanning Zhang, Hongyun Jiang, Yongquan Zheng, Xingang Liu
摘要: Atrazine is a widely used triazine herbicide, which poses a serious threat to human health and aquatic ecosystem. A montmorillonite–biochar composite (MMT/BC) was prepared for atrazine remediation. Biochar samples were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectrometer (XPS). Structural and morphological analysis of raw biochar (BC) and MMT/BC showed that MMT particles have been successfully coated on the surface of biochar. Sorption experiments in aqueous solution indicated that the MMT/BC has higher removal capacity of atrazine compared to BC (about 3.2 times). The sorption of atrazine on the MMT/BC was primarily controlled by both physisorption and chemisorption mechanisms. The amendment of MMT/BC increased the sorption capacity of soils and delayed the degradation of atrazine. Findings from this work indicate that the MMT/BC composite can effectively improve the sorption capacity of atrazine in aquatic environment and farmland soil and reduce the environmental risk.