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Chloramphenicol (CAP) is widely used in daily life, and its abuse hurts human health, so a suitable method is needed to solve the problem. In this study, the Ti/PbO2 electrodes prepared by the electroplating method were characterized. The CAP degradation effect and mechanism were investigated. It was shown that the electrode surface had a dense plating with a characteristic peak of β-PbO2 as the active component. The electrode had an oxygen precipitation potential of 1.695 V and a corrosion potential of 0.553 V, and a long service life (505.4 d). The degradation of CAP at Ti/PbO2 electrode followed a first-order kinetic reaction. The optimal degradation conditions (current density of 12.97 mA cm−2, electrolyte concentration of 50 mM, and solution pH of 6.38) were obtained by the response surface curve method. The degradation rate of CAP was 99.0% at 60 min. The results showed that the reactive groups leading to CAP degradation were mainly ·OH and SO42−, and only a tiny portion of CAP was directly oxidized on the electrode surface. The addition of Cl− favored the degradation of CAP, but reduced the mineralization rate. LC-MS analysis showed that ·OH mainly attacked the asymmetric centers (C1, C2) of weakly bound hydrogen atoms, resulting in underwent addition and substitution reactions. CAP was converted into two substances with m/z = 306 and m/z = 165. Finally, inorganic substances such as CO2 and H2O were generated. This study provided a new idea for preparing Ti/PbO2 electrode with high performance and the safe and efficient degradation of CAP.
Hao Dong; Xuyang Hu; Yinghao Zhang; Wenqiang Jiang; Xuan Zhang. Co/La modified Ti/PbO2 anodes for chloramphenicol degradation: Catalytic performance and reaction mechanism. Chemosphere 2021, 285, 131568 .
AMA StyleHao Dong, Xuyang Hu, Yinghao Zhang, Wenqiang Jiang, Xuan Zhang. Co/La modified Ti/PbO2 anodes for chloramphenicol degradation: Catalytic performance and reaction mechanism. Chemosphere. 2021; 285 ():131568.
Chicago/Turabian StyleHao Dong; Xuyang Hu; Yinghao Zhang; Wenqiang Jiang; Xuan Zhang. 2021. "Co/La modified Ti/PbO2 anodes for chloramphenicol degradation: Catalytic performance and reaction mechanism." Chemosphere 285, no. : 131568.
In order to evaluate the environmental risk caused by land application of sewage sludge, leaching characteristics of heavy metals and plant nutrients in the sewage sludge immobilized by composite phosphorus-bearing materials were investigated. Their cumulative release characteristics were confirmed. Furthermore, the first-order kinetics equation, modified Elovich equation, double-constant equation, and parabolic equation were used to explore dynamic models of release. Results showed that sewage sludge addition significantly increased electricity conductivity (EC) in leachates, and the concentrations of heavy metals (Cu, Cr, Zn) and plant nutrients (N, P, K) were also obviously increased. The highest concentrations of Cu, Cr, and Zn in the leachates were all below the limit values of the fourth level in the Chinese national standard for groundwater quality (GB/T14848-2017). The immobilization of composite phosphorus-bearing materials reduced the release of Cu and Cr, while increased that of Zn. The fitting results of modified Elovich model and double-constant model were in good agreement with the leaching process of heavy metals and plant nutrients, indicating their release process in soil under simulated leaching conditions was not a simple first-order reaction, but a complex heterogeneous diffusion process controlled by multifactor.
Shihe Li; Baihui Fang; Dongfang Wang; Xianqing Wang; Xiaobing Man; Xuan Zhang. Leaching Characteristics of Heavy Metals and Plant Nutrients in the Sewage Sludge Immobilized by Composite Phosphorus-Bearing Materials. International Journal of Environmental Research and Public Health 2019, 16, 5159 .
AMA StyleShihe Li, Baihui Fang, Dongfang Wang, Xianqing Wang, Xiaobing Man, Xuan Zhang. Leaching Characteristics of Heavy Metals and Plant Nutrients in the Sewage Sludge Immobilized by Composite Phosphorus-Bearing Materials. International Journal of Environmental Research and Public Health. 2019; 16 (24):5159.
Chicago/Turabian StyleShihe Li; Baihui Fang; Dongfang Wang; Xianqing Wang; Xiaobing Man; Xuan Zhang. 2019. "Leaching Characteristics of Heavy Metals and Plant Nutrients in the Sewage Sludge Immobilized by Composite Phosphorus-Bearing Materials." International Journal of Environmental Research and Public Health 16, no. 24: 5159.
Three D-π-A barbituric acid derivatives with simple structure and intramolecular charge transfer (ICT) mechanisms were synthesized. Molecular dynamics simulations have successfully explained that CB-1 exhibits the best aggregate induced emission (AIE) activity due to the electron-deficient barbituric acid and the electron-rich carbazole exhibit a conformation which similar to π-π stacking, resulting in a strong electrostatic attraction between the molecules, meanwhile the N-atom substituent of the carbazole is n-propane plays a hydrophobic role. At the same time, barbituric acid derivatives also have mechanochromic fluorescent properties. In addition, CB-1 and CB-3 exhibited outstanding fluorescence stability than CB-2 in aggregation state which can be used to detect nitroaromatic explosives in aqueous media. The Stern-Volmer quenching constant (Ksv) of CB-1 and CB-3 is 6.6 × 104 and 1 × 105 M-1, respectively.
Hanjun Zhang; Yuezhi Cui; Furong Tao; Datong Zhang; Zhen Xu; Li Guo. Multi-purpose barbituric acid derivatives with aggregation induced emission. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2019, 223, 117320 .
AMA StyleHanjun Zhang, Yuezhi Cui, Furong Tao, Datong Zhang, Zhen Xu, Li Guo. Multi-purpose barbituric acid derivatives with aggregation induced emission. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 2019; 223 ():117320.
Chicago/Turabian StyleHanjun Zhang; Yuezhi Cui; Furong Tao; Datong Zhang; Zhen Xu; Li Guo. 2019. "Multi-purpose barbituric acid derivatives with aggregation induced emission." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 223, no. : 117320.
The widely used sulfonylurea herbicides have caused negative effects on the environment and human beings. Electrochemical degradation has attracted much attention in the treatment of refractory organic compounds due to its advantage of producing no secondary pollution. Three kinds of IrO2-based dimensionally stable anodes (DSAs) were used to degrade nicosulfuron by a batch electrochemical process. The results showed that a well-distributed crack network was formed on the Ti/Ta2O5-IrO2 electrode and Ti/Ta2O5-SnO2-IrO2 electrode due to the different coefficients of thermal expansion between the Ti substrate and oxide coatings. The oxygen evolution potential (OEP) increased according to the order of Ti/RuO2-IrO2 < Ti/Ta2O5-SnO2-IrO2 < Ti/Ta2O5-IrO2. Among the three electrodes, the Ti/Ta2O5-IrO2 electrode showed the highest efficiency and was chosen as the experimental electrode. Single factor experiments were carried out to obtain the optimum electrolysis condition, shown as follows: currency intensity 0.8 A; electrode spacing 3 cm, electrolyte pH 3. Under the optimum conditions, the degradation of nicosulfuron followed first-order kinetics and was mainly due to indirect electrochemical oxidation. It was a typical diffusion-controlled electrochemical process. On the basis of the intermediate identified by high performance liquid chromatograph-mass spectrometry (HPLC-MS), two possible degradation routes were proposed.
Rui Zhao; Xuan Zhang; Fanli Chen; Xiaobing Man; Wenqiang Jiang. Study on Electrochemical Degradation of Nicosulfuron by IrO2-Based DSA Electrodes: Performance, Kinetics, and Degradation Mechanism. International Journal of Environmental Research and Public Health 2019, 16, 343 .
AMA StyleRui Zhao, Xuan Zhang, Fanli Chen, Xiaobing Man, Wenqiang Jiang. Study on Electrochemical Degradation of Nicosulfuron by IrO2-Based DSA Electrodes: Performance, Kinetics, and Degradation Mechanism. International Journal of Environmental Research and Public Health. 2019; 16 (3):343.
Chicago/Turabian StyleRui Zhao; Xuan Zhang; Fanli Chen; Xiaobing Man; Wenqiang Jiang. 2019. "Study on Electrochemical Degradation of Nicosulfuron by IrO2-Based DSA Electrodes: Performance, Kinetics, and Degradation Mechanism." International Journal of Environmental Research and Public Health 16, no. 3: 343.
Large amounts of fly ash and sewage sludge are produced annually in China. The treatment and disposal of such byproducts have become urgent problems that need to be solved. In order to achieve the possibility of realizing land applications for sewage sludge, fly ash and trimercapto-s-triazine trisodium salt (TMT) were used as immobilizing agents, and their passivation effects on four kinds of heavy metals (Cu, Ni, Pb, and Zn) were evaluated. The results showed that the resulting sewage sludge met Chinese standard GB/T23486-2009. When the addition was 10–20% fly ash or 0.4–0.6% TMT, the optimum immobilization effect was obtained. The synergistic passivation of 20% fly ash +0.5% TMT was superior to that of either fly ash or TMT alone. The addition of sewage sludge during the ryegrass growth process significantly increased the plant height, the number of tillers, the chlorophyll content, and the biomass of the ryegrass over the brown soil. The adverse effect of the heavy metals on the ryegrass growth could be alleviated by the passivation effect of fly ash and TMT. The immobilization performance of the fly ash was mainly due to the formation of precipitation and the ion exchange, while that of TMT was due to chelate precipitation.
Dong-Fang Wang; Shi-He Li; Xian-Qing Wang; Ling-Xu Li; Xuan Zhang. Synergistic Passivation of Fly Ash and TMT on Heavy Metals in Sewage Sludge. Sustainability 2018, 10, 4731 .
AMA StyleDong-Fang Wang, Shi-He Li, Xian-Qing Wang, Ling-Xu Li, Xuan Zhang. Synergistic Passivation of Fly Ash and TMT on Heavy Metals in Sewage Sludge. Sustainability. 2018; 10 (12):4731.
Chicago/Turabian StyleDong-Fang Wang; Shi-He Li; Xian-Qing Wang; Ling-Xu Li; Xuan Zhang. 2018. "Synergistic Passivation of Fly Ash and TMT on Heavy Metals in Sewage Sludge." Sustainability 10, no. 12: 4731.
The safe disposal of sewage sludge during the process of municipal wastewater treatment has become one of the major concerns of increased production. Land application was thought of as a more economical method for sewage sludge disposal than landfill and incineration. However, the presence of heavy metals in sewage sludge restricted the use of land application. The environmental risk of heavy metals was dependent on their contents, chemical speciations, and soil characteristics. Composting and chemical immobilization were the commonly used methods to immobilize the heavy metals in sewage sludge. The immobilization mechanism and speciation transformation of heavy metals during the composting process were presented. Aluminosilicate, phosphorus-bearing materials, basic compounds, and sulfides were reviewed as the commonly used chemical immobilizing agents. The problems that occur during the immobilization process were also discussed. The combination of different methods and the modification of chemical immobilizing agents both improved the fixation effect on heavy metals.
Xuan Zhang; Xian-Qing Wang; Dong-Fang Wang. Immobilization of Heavy Metals in Sewage Sludge during Land Application Process in China: A Review. Sustainability 2017, 9, 2020 .
AMA StyleXuan Zhang, Xian-Qing Wang, Dong-Fang Wang. Immobilization of Heavy Metals in Sewage Sludge during Land Application Process in China: A Review. Sustainability. 2017; 9 (11):2020.
Chicago/Turabian StyleXuan Zhang; Xian-Qing Wang; Dong-Fang Wang. 2017. "Immobilization of Heavy Metals in Sewage Sludge during Land Application Process in China: A Review." Sustainability 9, no. 11: 2020.
The application of different multivariate statistical techniques for the interpretation of a complex data matrix obtained during 2000–2007 from the watercourses in the Southwest New Territories and Kowloon, Hong Kong was presented in this study. The data set consisted of the analytical results of 23 parameters measured monthly at 16 different sampling sites. Hierarchical cluster analysis grouped the 12 months into two periods and the 16 sampling sites into three groups based on similarity in water quality characteristics. Discriminant analysis (DA) provided better results both temporally and spatially. DA also offered an important data reduction as it only used four parameters for temporal analysis, affording 84.2% correct assignations, and eight parameters for spatial analysis, affording 96.1% correct assignations. Principal component analysis/factor analysis identified four latent factors standing for organic pollution, industrial pollution, nonpoint pollution, and fecal pollution, respectively. KN1, KN4, KN5, and KN7 were greatly affected by organic pollution, industrial pollution, and nonpoint pollution. The main pollution sources of TN1 and TN2 were organic pollution and nonpoint pollution, respectively. Industrial pollution had high effect on TN3, TN4, TN5, and TN6.
Xuan Zhang; Qishan Wang; Yanfang Liu; Jing Wu; Miao Yu. Application of multivariate statistical techniques in the assessment of water quality in the Southwest New Territories and Kowloon, Hong Kong. Environmental Monitoring and Assessment 2010, 173, 17 -27.
AMA StyleXuan Zhang, Qishan Wang, Yanfang Liu, Jing Wu, Miao Yu. Application of multivariate statistical techniques in the assessment of water quality in the Southwest New Territories and Kowloon, Hong Kong. Environmental Monitoring and Assessment. 2010; 173 (1-4):17-27.
Chicago/Turabian StyleXuan Zhang; Qishan Wang; Yanfang Liu; Jing Wu; Miao Yu. 2010. "Application of multivariate statistical techniques in the assessment of water quality in the Southwest New Territories and Kowloon, Hong Kong." Environmental Monitoring and Assessment 173, no. 1-4: 17-27.