SEPARATION AND PURIFICATION TECHNOLOGY
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2020
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IF 5.774
Rui Li,Haoran Dong,Ran Tian,Jie Chen,Qianqian Xie
In this work, bare nanoscale zero-valent iron (NZVI) and the modified NZVI (sulfide-modified NZVI, Ni/NZVI and activated carbon supported NZVI) were utilized to activate sulfite for the removal of the target pollutant sulfamethazine (SMT). Some critical factors influencing the removal process were investigated, including dosage of sulfite and nanoparticles (NPs), ratios of modifier/NZVI, dissolved oxygen, initial pH values, groundwater components and aging time of NPs. Under the optimal conditions, in terms of the dosage of sulfite/NPs and the ratio of modifier/NZVI, all the modified NZVI showed a better performance than the bare NZVI. Dissolved oxygen was determined to be an essential factor for producing reactive radicals in all the activation processes. The active radicals were identified to be SO 4 · and HO·, and HO· was evidenced as the principal reactive species. Initial pH value significantly affected the SMT removal, which was obviously inhibited under alkaline condition. In such case, Ni/NZVI showed a better performance than the other NPs due to the catalysis effect of Ni. It was also found that the groundwater components (e.g., HCO 3 − , Ca 2+ , SO 4 2− , and humic acid) could restrain the removal process because of the buffering effect, the radical scavenging effect and some other effects (e.g., surface precipitation). Spectroscopic analysis of the fresh and aged (30 d) NPs illustrated that both bare and modified NZVI were slightly oxidized in the air, and could still be employed for the activation of sulfite.
研究领域:
环境科学
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水处理
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纳米技术
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污染物去除
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DOI
高影响因子
RSC Advances
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2015
·Vol. 5
·期 103
·84856-84864
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IF 3.84
Qianchi Ma,Lei Liu,Wei Cui,Ruifeng Li,Tingting Song,Zhaojie Cui
Model aqueous solutions of perfluorooctanoic acid (PFOA, 100 mg L−1) were electro-oxidized in a homemade container. The electrocatalytic behavior and anodic performance of Ti/SnO2–Sb/Yb–PbO2, Ti/SnO2–Sb–PbO2 and Ti/SnO2–Sb–Yb anodes in sodium electrolytes were compared. The SnO2–Sb/Yb–PbO2 anode demonstrated better electrocatalytic performance compared with the SnO2–Sb–PbO2 and SnO2–Sb–Yb electrodes in terms of both degradation and defluorination. Then a systematic experimental study was designed as follows to analyze the influencing factors: initial concentration of PFOA (10 mg L−1 to 200 mg L−1), current density (1 mA cm−2 to 40 mA cm−2), initial pH value (3 to 11) and electrode distance (5 mm to 20 mm). After a 150 min electrolysis, the optimum reaction conditions were obtained and the degradation and defluorination ratios reached 95.11 ± 3.9% and 75.7 ± 2.8%, respectively. Under the optimum conditions, the degradation of PFOA followed pseudo-first-order kinetics (0.0193 min−1) and the degradation half-life was 35.9 min. The produced F− was measured using a fluoride ion selective electrode, whereas the intermediate PFCAs with short-chain lengths were measured using HPLC-MS. A detailed degradation pathway was proposed in this study by analyzing the intermediates and the recovery of fluoride.
研究领域:
环境科学
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化学工程
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分析化学
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DOI
高影响因子
Journal of Environmental Sciences
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2022
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IF 6.796
Jianhui Xu,Pengxu Wang,Shenggui Chen,Lei Li,Dan Li,Yunfei Zhang,Qi Wu,Jinhong Fan,Luming Ma
Here, we report the production of 3D-printed MoS 2 /Ni electrodes (3D-MoS 2 /Ni) with long-term stability and excellent performance by the selective laser melting (SLM) technique. As a cathode, the obtained 3D-MoS 2 /Ni could maintain a degradation rate above 94.0% for florfenicol (FLO) when repeatedly used 50 times in water. We also found that the removal rate of FLO by 3D-MoS 2 /Ni was about 12 times higher than that of 3D-printed pure Ni (3D-Ni), attributed to the improved accessibility of H*. In addition, the electrochemical characterization results showed that the electrochemically active surface area of the 3D-MoS 2 /Ni electrode is about 3-fold higher than that of the 3D-Ni electrode while the electrical resistance is 4 times lower. Based on tert -butanol suppression, electron paramagnetic resonance and triple quadrupole mass spectrometer experiments, a “dual path” mechanism and possible degradation pathway for the dechlorination of FLO by 3D-MoS 2 /Ni were proposed. Furthermore, we also investigated the impacts of the cathode potential and the initial pH of the solution on the degradation of FLO. Overall, this study reveals that the SLM 3D printing technique is a promising approach for the rapid fabrication of high-stability metal electrodes, which could have broad application in the control of water contaminants in the environmental field.
研究领域:
环境科学
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材料科学
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电化学
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水处理
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DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
·
IF 9.136
Xiaoli Zhang,Penghui Shi,Wenbin Zhao,Wu Lu,Feng Li,Yulin Min,Qunjie Xu
Advanced oxidation processes (AOPs) focusing on non-thermal plasma induced by dielectric barrier discharge (DBD) are adequate sources of diverse reactive oxygen species beneficial for water and wastewater treatment. The degradation of methylene blue (MB) was investigated using plasma liquid dielectric barrier discharge with a multineedle-to-plane reactor. MB at 20 mg/L concentration was almost completely degraded after 40 min of treatment. In this study, several important parameters, such as input voltage, initial concentration, initial pH, discharge gap, tip radius of curvature, and presence of radical, were evaluated, and their effects on MB degradation rate were investigated. The degradation rate of MB increased with initial pH. By contrast, the degradation rate showed a downward trend with increasing initial concentration, discharge distance, and tip curvature radius. O 3 and H 2 O 2 produced during the degradation process considerably influenced the entire degradation process, especially when the quenching agents of HO ⋅ , O 2 · - and e − were added, and the degradation efficiency was obviously reduced. According to the measured spectrum, the possible process of the discharge process was analyzed, and the COMSOL finite element simulation is performed to obtain the visualization of the discharge model. This work can provide exploratory platforms for comprehensively understanding and enhancing MB degradation in DBD plasma technology.
研究领域:
环境科学
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化学工程
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等离子体物理
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水处理技术
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产品关联
DOI
高影响因子
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