摘要：
A significant amount of antimony (Sb) enters into the environment every year because of the wide use of Sb compounds in industry and agriculture. The exposure to Sb, either direct consumption of Sb or indirectly, may be fatal to the human health because both antimony and antimonide are toxic. Firstly, the introduction of Sb chemistry, distribution and health threats are presented in this review, which is essential to the removal techniques. Then, we provide the recent and common techniques to remove Sb, including adsorption, coagulation/flocculation, membrane separation, electrochemical methods, ion exchange and extraction. Removal techniques concentrate on the advantages, drawbacks, economical efficiency and the recent achievements of each technique. We also take an overall consideration of experimental conditions, comparison criteria, and economic aspects.
摘要：
Chromium metal-organic framework (MIL-101(Cr)) has been widely studied for removing organic contaminants from aqueous solutions due to its excellent water stability and giant pore size, but its low adsorption capacity limits the application. In this study, a new adsorbent MIL-101 loaded with CuCo bimetallic nanoparticles (CuCo/MIL-101) was successfully fabricated and applied in removal of tetracycline (TC) from aqueous solutions. The adsorption capacity of CuCo/MIL-101 for TC increased by 140% compared with that of pure MIL-101, which may be attributed to the chemical bonding between Cu and Co BNPs in MIL-101 and TC molecules. The effects of pH, ionic strength, humic acid and contact time on the adsorption were also discussed in detail. The results showed that the removal efficiency of TC solution with high concentration (100mgL(-1)) by CuCo/MIL-101 was still as high as 82.9%. The data of adsorption kinetics and isotherms could be well fitted by Elovich model and Freundlich model, respectively. According to the fitting parameters, the maximum adsorption capacity of CuCo/MIL-101 reached up to 225.179mgg(-1). Additionally, the adsorption process of TC onto CuCo/MIL-101 was spontaneous and endothermic. Electrostatic interactions could play an important role in the adsorption process. The enhanced adsorption capacity, excellent reusability and water stability demonstrated the potential of CuCo/MIL-101 composite as a novel adsorbent for the removal of TC from aqueous solutions.
摘要：
A pot experiment was used to investigate arsenic (As) speciation and accumulation in rice, as well as its concentration in both heavily contaminated and moderately contaminated soils amended with manganese oxide-modified biochar composites (MBC) and biochar alone (BC). In heavily As-contaminated soil, application of BC and MBC improved the weight of above-ground part and rice root, whereas in moderately As-contaminated soil, the application of MBC and low rate BC amendment increased rice root, grain weight and the biomass of the plant. Arsenic reduction in different parts of rice grown in MBC-amended soils was greater than that in plants cultivated in BC-amended soils. Such reduction can be attributed to the oxidation of arsenite, As(III), to arsenate, As(V), by Mn-oxides, which also had a strong adsorptive capacity for As(V). MBC amended to As-contaminated soil had a positive effect on amino acids. The Fe and Mn levels in the iron-manganese plaque that formed on the rice root surface differed among the treatments. MBC addition significantly increased Mn content (p < 0.05); the application of 2.0% MBC increased Mn content 36- and 10-fold compared to the control in heavily and moderately As contaminated soils, respectively. The results indicate that application of Mn oxide-modified biochar to As-contaminated paddy soil could effectively remediate contaminated soil and reduce As accumulation in edible parts of rice. (C) 2016 Elsevier Ltd. All rights reserved.
作者机构：
[Wang, Zhongjie; Shao, Jihai; Yu, Gongliang; Li, Renhui; Jiang, Yongguang; Peng, Xin] Chinese Acad Sci, Inst Hydrobiol, Wuhan 430072, Peoples R China.;[Shao, Jihai] Hunan Agr Univ, Coll Resources & Environm, Changsha 410128, Hunan, Peoples R China.;[Xu, Yao] Nanjing Normal Univ, Coll Geog Sci, Dept Environm Sci & Engn, Nanjing 210046, Peoples R China.;[Wang, Zhongjie; Jiang, Yongguang] Chinese Acad Sci, Grad Univ, Beijing 100039, Peoples R China.
通讯机构：
[Li, Renhui] Chinese Acad Sci, Inst Hydrobiol, Wuhan 430072, Peoples R China.
关键词：
Microcystis aeruginosa;Photosynthesis;Gene expression;Chlorophyll a fluorescence
摘要：
In order to explore the potential targets of toxicity of beta-ionone on the photosynthetic system of Microcystis aeruginosa, the polyphasic rise in chlorophyll a (Chl a) fluorescence transient and transcript expression for key genes in photosystem II (PSII) of M. aeruginosa NIES-843 were studied. The EC(50) value of beta-ionone on M. aeruginosa NIES-843 was found to be 21.23 +/- 1.87 mg/L It was shown that beta-Ionone stress can lead to a decrease in pigment content of M. aeruginosa NIES-843 cells, and that carotenoids were more sensitive to beta-ionone stress than Chl a. The normalized Chl a fluorescence transients were slightly decreased at 6.67 and 10 mg/L beta-ionone, but significantly increased at 15, 22.5 and 33.75 mg/L There was no significant variation on transcript expression of psbA and psbO at a concentration of 6.67 mg/L beta-ionone. but they were down-regulated at 22.5 mg/L Ultrastructural examination by transmission electron microscopy indicated that the thylakoids were distorted, and the thylakoid membrane stacks began to collapse when M. aeruginosa NIES-843 was exposed to beta-ionone at a concentration of 22.5 and 33.75 mg/L Our results indicate that the reaction centre of PS II and the electron transport at the acceptor side of PS II are the targets responsible for the toxicity of beta-ionone on the PS II of M. aeruginosa NIES-843. (C) 2011 Elsevier B.V. All rights reserved.
摘要：
In tropical and subtropical soils, sesquioxides and soil organic matter (SOM) are major binding agents for aggregates. However, the biotic and abiotic contributions to aggregation are often difficult to distinguish. In this study, we attempted to assess their contributions to aggregation separately, as indicated by aggregate size distribution and specific surface area (SSA). Our objectives were (i) to determine aggregate size distribution and SSA before and after removal of sesquioxides and SOM, and (ii) to assess the contributions of sesquioxides and SOM to soil aggregation. An oxide-rich Ultisol under long-term fertilization was extracted by water as a control, oxalate, dithionite-citrate-bicarbonate (DCB), or by H<inf>2</inf>O<inf>2</inf> in the absence of any physical disturbance. The aggregate size distribution, Fe/Al oxides, soil organic C (SOC), and SSA of the soil before and after extraction were determined. Our results showed that the DCB and oxalate solutions broke down the sand-sized aggregates most intensively, whereas the H<inf>2</inf>O<inf>2</inf> treatment disrupted 0.25-2.0mm aggregates intensively, indicating that SOM is the major binding agent for aggregates of this size. A slight change either in SOC stock after removal of Fe/Al oxides by DCB and oxalate or in Fe/Al oxides after removal of SOC by H<inf>2</inf>O<inf>2</inf> indicated that organo-mineral complexes are a minor binding mechanism of aggregation in the soil studied. The SSA was reduced by 72-84% in the soil extracted by DCB, followed by 32.0-35.9% after the oxalate extraction, whereas the removal of SOM increased SSA by 3.8-12.6%. Our results showed that Fe/Al oxides played a major role in aggregation in the Ultisols studied. The difference in the major binding agent for different aggregate size classes is another reason to explain why the hierarchy aggregate concept is not applicable to oxide-rich soils. This study, however, could not assess their contributions to soil aggregation precisely, because of the difficulty in tracing aggregate dynamics. To better understand the mechanisms of soil aggregation we need more works in the future.
摘要：
Topsoil carbon (C) stocks are known to decrease as a consequence of the conversion of natural ecosystems to plantations or croplands; however, the effect of land use change on subsoil C remains unknown. Here, we hypothesized that the effect of land use change on labile subsoil organic C may be even stronger than for topsoil due to upward concentration of plantations and crops root systems. We evaluated soil labile organic C fractions, including particulate organic carbon (POC) and its components [coarse POC and fine POC], light fraction organic carbon (LFOC), readily oxidizable organic carbon, dissolved organic carbon (DOC) and microbial biomass down to 100 cm soil depth from four typical land use systems in subtropical China. Decrease in fine root biomass was more pronounced below 20 cm than in the overlying topsoil (70% vs. 56% for plantation and 62% vs. 37% for orchard. respectively) driving a reduction in subsoil labile organic C stocks. Land use changes from natural forest to Chinese fir plantation, Chinese chestnut orchard, or sloping tillage reduced soil organic C stocks and that of its labile fractions both in top and subsoil (20-100 cm). POC reduction was mainly driven by a decrease in fine POC in topsoil, while DOC was mainly reduced in subsoil. Fine POC, LFOC and microbial biomass can be useful early indicators of changes in topsoil organic C. In contrast, LFOC and DOC are useful indicators for subsoil. Reduced proportions of fine POC, LFOC, DOC and microbial biomass to soil organic C reflected the decline in soil organic C quality caused by land use changes. We conclude that land use changes decrease C sequestration both in topsoil and subsoil, which is initially indicated by the labile soil organic C fractions. (C) 2015 Elsevier Ltd. All rights reserved.
摘要：
In this study, the oxidized multiwalled carbon nanotube (O-MWCNTs) was obtained by a simple method, and investigated by various techniques (SEM, TEM, FT-IR, XPS and zeta potential) for the removal of pefloxacin and Cu (II). The mutual effects of their adsorption onto O-MWCNTs were comprehensively clarified with sole and binary systems with adsorption kinetics, sorption thermodynamic and sorption isotherm models. The results indicated that there are site enhancement and competition of pefloxacin and Cu(II) on O-MWCNTs. According to mechanism investigation on the adsorption of pefloxacin and Cu(II) by XPS analysis, pH impact study, electrostatic interaction and pi-pi interactions, the low concentration of Cu(II)/pefloxacin could act as a bridge between pefloxacin/Cu(II) and O-MWCNTs, which significantly enhances the adsorption of pefloxacin/Cu(II). This study provided effective method and valuable reference for the elimination of pefloxacin/Cu(II) from aquatic environments. (C) 2018 Elsevier B.V. All rights reserved.
期刊：
Science of The Total Environment,2012年429:300-308 ISSN：0048-9697
通讯作者：
Yang, Shaogui
作者机构：
[Luo, Si; Yang, Shaogui; Sun, Cheng] Nanjing Univ, Sch Environm, State Key Lab Pollut Control & Resource Reuse, Nanjing 210093, Jiangsu, Peoples R China.;[Luo, Si; Gu, Ji-Dong] Hunan Agr Univ, Coll Resources & Environm, Changsha 410128, Hunan, Peoples R China.;[Gu, Ji-Dong] Univ Hong Kong, Sch Biol Sci, Lab Environm Microbiol & Toxicol, Hong Kong, Hong Kong, Peoples R China.
通讯机构：
[Yang, Shaogui] Nanjing Univ, Sch Environm, State Key Lab Pollut Control & Resource Reuse, Nanjing 210093, Jiangsu, Peoples R China.
关键词：
Bimetallic iron–silver;PBDEs;Debromination;Nano technologies;Zero valent iron;Microwave energy
摘要：
This study focused on the enhanced debromination of decabromodiphenyl ether (BDE-209) and 2,2,4,4'-tetrabromodiphenyl ether (BDE-47) by Fe-Ag nano-particles under microwave radiation (Fe-Ag/MW). Fe-Ag bimetallic nano-particles were synthesized by reductive deposition of Ag on nano-iron and characterized with a number of techniques, including BET, XRD, TEM and XPS. Approximately 97% of BDE-209 or 78% of BDE-47 were rapidly transformed to its degradation products within 8 min in the Fe-Ag/MW system. The dehalogenation efficiency of polybrominated diphenyl ethers (PBDEs) was enhanced apparently by microwave radiation. Moreover, the microwave thermal energy played a significant role in accelerating the degradation reactions. Compared with nano-iron alone, the deposition of Ag also increased the rates of degradation. GC-MS and LC-MS/MS analyses of PBDEs' degradation products reveals that the possible degradation pathway proceeds through stepwise debromination from [n]-bromo- to [n-1]-bromo-DE, with bromine being substituted by hydrogen sequentially. Di- to nona-brominated congeners were formed during BDE-209 reduction, while diphenyl ether to tri-BDEs were observed during BDE-47 degradation. These results suggest that PBDEs can be debrominated rapidly by the innovative processes that may be environmentally friendly in applications. (C) 2012 Elsevier B.V. All rights reserved.
摘要：
Studies were performed to evaluate influence of biochar addition on physico-chemical process, heavy metals transformation and bacterial community diversity during composting of sediment with agricultural wastes. Simultaneously, the relationships between those parameters including heavy metals and bacterial community compositions were evaluated by redundancy analysis (RDA). The results show that the extraction efficiency of DTPA extractable heavy metals decreased in both piles, and reduced more in pile with biochar addition about 0.1-2.96%. Biochar addition dramatically influenced the bacterial community structure during the composting process. Moreover, the bacterial community composition was significantly correlated with C/N ratio, water soluble carbon (WSC), and organic matter (OM) (P < 0.05) in pile with biochar addition; while significantly correlated with temperature, WSC, and C/N ratio in pile which was free of biochar. This study would provide some valuable information for improving the composting for disposal of river sediment with heavy metals contamination. (C) 2017 Elsevier Ltd. All rights reserved.
摘要：
Municipal solid waste incinerator fly ash (IFA) is categorized as a hazardous waste, which requires proper treatment prior to landfilling due to its high concentrations of toxic elements. This study developed an innovative and cleaner method for stabilization/solidification (S/S) of IFA by the incorporation of supplementary cementitious materials (SCMs) and green stabilizers. Quantitative X-ray diffraction and thermogravimetric analyses indicated that toxic elements in IFA inhibited the cement hydration. Therefore, the single use of cement (10 wt%) was not efficient for the immobilization of toxic elements, especially for Pb. The incorporation of SCMs (20 wt% of binder) such as silica fume facilitated the formation of additional cement hydrates and reduced Pb leachability by 36.3%. The addition of green stabilizers such as potassium dihydrogen phosphate (KDP) and wood waste-derived biochar also improved the immobilization of toxic elements. KDP directly combined with Pb2+ to form a precipitate of Pb-3(PO4)(2), whereas biochar promoted the generation of cement hydrates for S/S via the effect of internal curing. The incorporation of silica fume (40 wt%) in the binder was the most effective. Overall, this study demonstrated that the selected green binders can serve as low-carbon and high-efficient material for S/S of hazardous ash residue such as IFA. (C) 2019 Elsevier Ltd. All rights reserved.
作者：
Wan, Zhonghao;Sun, Yuqing;Tsang, Daniel C. W.;Yu, Iris K. M.;Fan, Jiajun;Clark, James H.;Zhou, Yaoyu;Cao, Xinde;Gao, Bin;Ok, Yong Sik
期刊：
Green Chemistry,2019年21(17):4800-4814 ISSN：1463-9262
作者机构：
[Sun, Yuqing; Wan, Zhonghao; Tsang, Daniel C. W.; Zhou, Yaoyu; Yu, Iris K. M.] Hong Kong Polytech Univ, Dept Civil & Environm Engn, Hong Kong, Peoples R China.;[Fan, Jiajun; Clark, James H.; Yu, Iris K. M.] Univ York, Dept Chem, Green Chem Ctr Excellence, York YO10 5DD, N Yorkshire, England.;[Zhou, Yaoyu] Hunan Agr Univ, Coll Resourres & Environm, Hunan Int Sci & Technol Cooperat Base Agr Typ Pol, Changsha 410128, Hunan, Peoples R China.;[Cao, Xinde] Shanghai Jiao Tong Univ, Sch Environm Sci & Engn, Shanghai 200240, Peoples R China.;[Gao, Bin] Univ Florida, Dept Agr & Biol Engn, Gainesville, FL 32611 USA.
摘要：
We have developed a sustainable graphitic biochar for environmental remediation from wood waste through catalytic pyrolysis under the synergistic effects between CO2 and Cu heteroatoms, which for the first time are found to significantly enhance the oxygen functionalities, defective sites, and highly ordered sp2-hybridized carbon matrix. The copper-doped graphitic biochar (Cu-GBCs) were further characterized by XRD, FTIR, Raman, XPS, etc., revealing that the modified specific surface area, pore structure, graphitization, and active sites (i.e., defective sites and ketonic group) on the Cu-GBCs corresponded to the synergistic Cu species loading and Cu-induced carbon-matrix reformation under CO2 environment during pyrolysis. The catalytic ability of the Cu-GBCs was evaluated using the ubiquitous peroxydisulfate (PDS) activation system for the removal of various organic contaminants (i.e., Rhodamine B, phenol, bisphenol A, and 4-chlorophenol), and gave the highest degradation rate of 0.03122 min-1 in comparison with those of pristine GBCs and N2-pyrolyzed Cu-GBCs ranging from 0.0056 to 0.0094 min-1. The synergistic effects were attributed to the encapsulated Cu heteroatoms, evolved ketonic groups, and abundant unconfined π electrons within the carbon lattice. According to scavenger experiments, ESR analysis, and the two-chamber experiments, selective and sustainable non-radical pathways (i.e., singlet oxygenation and electron transfer) mediated by Cu-induced metastable surface complex were achieved in the Cu-GBC/PDS system. This study offers the first insights into the efficacy, sustainability, and mechanistic roles of Cu-GBCs as an emerging carbon-supported catalyst, and facilitates the development of biochar-based materials as sustainable catalysts in green environmental remediation.
摘要：
Antioxidative response of Phanerochaete chrysosporium induced by silver nanoparticles (AgNPs) and their toxicity mechanisms were comprehensively investigated in a complex system with 2,4-dichlorophenol (2,4-DCP) and Ag+. Malondialdehyde content was elevated by 2,4-DCP, AgNPs, and/or Ag+ in concentration- and time-dependent manners within 24 h, indicating an increase in lipid peroxidation. However, beyond 48 h of exposure, lipid peroxidation was alleviated by upregulation of intracellular protein production and enhancement in the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). Comparatively, POD played more major roles in cell protection against oxidative damage. Furthermore, the dynamic change in reactive oxygen species (ROS) level was parallel to that of oxidized glutathione (GSSG), and ROS levels correlated well with GSSG contents (R-2 = 0.953) after exposure to AgNPs for 24 h. This finding suggested that elimination of oxidative stress resulted in depletion of reduced glutathione. Coupled with the analyses of anoxidative responses of P. chrysosporium under the single and combined treatments of AgNPs and Ag+, HAADF-STEM, SEM, and EDX demonstrated that AgNP-induced cytotoxicity could originate from the original AgNPs, rather than dissolved Ag+ or the biosynthesized AgNPs. (C) 2018 Elsevier Ltd. All rights reserved.
