SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Ran Yang,Jun Cai,Hu Yang
Zero-valent aluminum (ZVAl) is a promising reductant because of its relatively low redox potential , which can efficiently activate molecular oxygen to generate reactive oxygen species . However, its long-term performance is limited by the intrinsic dense oxide layer and the passivation effect of the accumulative Al-(hydr)oxide on its surface during the reaction. In this study, four clay minerals with different compositions were mixed with ZVAl by ball milling to obtain four composites of ZVAl and clay (ZVAl-Clay), which were used to degrade a high concentration of 4-chlorophenol (4-CP) under ambient conditions. The oxidation efficiencies of different ZVAl-Clays were strongly relevant to Fe contained in the clay minerals. The Fe-free ZVAl-Clay presented poor oxidation performance, whereas the reaction efficiencies of those ZVAl composites with Fe-bearing clays exhibited varying degrees of improvement. In comparison with the original ZVAl, the highest oxidation rate increased by 23 times, the maximum increased OH production was approximately 8 times, and the corresponding mineralization efficiency improved by 38.7%. However, the levels of improved oxidation performance of various ZVAl-Clays were not positively correlated with their actual total Fe contents, and their degradation efficiencies might also be affected by other physical and/or chemical properties of different clays. The synergistic mechanism revealed by various characterizations was that electron transfer might occur from ZVAl to the structural Fe(III) of the clay through the basal plane or edge of clays triggered by ball milling. Thus, the partially produced Fe(II) on the clay surface promoted the Fenton-like reaction to decompose H 2 O 2 into OH for efficient oxidation of 4-CP. In short, the ZVAl composites with Fe-bearing clays deserved further exploration as potential materials for efficient degradation of organic matters in wastewater samples.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
Desalination and Water Treatment
·
2016
·
IF 1.272
Xiao-ling Shao,Cheng-fei Zou,Fu-xing Wang,Yang Xiong,Xiang-yang Wu
The kinetics of the oxidation of chlorophenols (CPs) by potassium permanganate was studied in the present study, along with the changes in oxidant dosage, pH, temperature, and real water matrices. The reactions between permanganate and three kinds of CPs, i.e. 4-chlorophenol (4-MCP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP), are second order overall and first-order with respect to each reactant. The degradation rates of the CPs increase with increasing permanganate dosage or temperature. pH plays an important role during permanganate oxidation. With the increase in pH from 4.0 to 10.0, the reaction rates of 4-MCP and 2,4-DCP decrease first and then increase, and finally decrease rapidly when pH > pKa, while the rates of 2,4,6-TCP decrease continuously. The degradation rates of the CPs are obviously higher in real water than in pure water. The reaction rate follows the order of 2,4,6-TCP > 2,4-DCP > 4-MCP under acidic conditions, and follows the reverse order under alkaline conditions in both pure water and real water.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2018
·Vol. 165
·期 11
·H717
·
IF 3.662
Zhiqiao He,Jiajie Zhou,Xinwen Huang,Shihan Zhang,Shuang Song
The β-PbO2 of a Ti/Sn-SbOx/PbO2 electrode was modified with polydimethylsiloxane (PDMS) (Ti/Sn-SbOx/PbO2-PDMS) through a facile electrodeposition method. The results from scanning electron microscopy, energy-dispersive spectrometry and X-ray diffraction demonstrated that the PDMS was irreversibly adsorbed on the β-PbO2 of Ti/Sn-SbOx/PbO2-PDMS, leading to a decrease in the crystal size, surface cracks and preferential growth trend of β-PbO2. Compared with its PDMS-unmodified counterparts, the Ti/Sn-SbOx/PbO2-PDMS electrode exhibited relatively higher activity, selectivity and stability in the anodic oxidation of p-chlorophenol. Moreover, the Ti/Sn-SbOx/PbO2-PDMS electrode was more stable than the Ti/Sn-SbOx/PbO2 electrode, as evidenced by the accelerated life test. Based on the quantitative measurements of contact angle, hydroxyl radicals (HO•) and the initial surface concentration of various p-substituted phenols, including p-cresol, p-methoxyphenol, phenol, and p-chlorophenol, and with the help of electrochemical characterization of linear sweep voltammetry, it could be concluded that the improved electrochemical activity and stability of Ti/Sn-SbOx/PbO2-PDMS originated from the enhanced hydrophobicity of the electrode surface. Different from a traditional Ti/Sn-SbOx/PbO2 electrode with adsorbed HO• as the dominant active species, the Ti/Sn-SbOx/PbO2-PDMS with a hydrophobic surface favors the generation of more free HO•.
研究领域:
材料科学
·
环境科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2021
·
IF 5.909
Jihong Xu,Peisheng Zhou,Penghui Shi,Yulin Min,Qunjie Xu
Concern about nitrogen-doped carbon materials for pollutant removal via nonradical pathway is mounting. In this study, graphite carbon nitride (g-C 3 N 4 ) was transformed into a high nitrogen-doped three-dimensional carbon material (N-CM) through the “metal template method”. The synthesized N-CM showed high efficiency in removing 2,4-dichlorophenol (2,4-DCP) via the activation of peroxymonosulfate (PMS). Under neutral condition, 2,4-DCP (0.2 g/L) was completely eliminated with 0.3 g/L PMS and 0.1 g/L N-CM900 in 30 min. Initial pH value, inorganic anions, and cycle experiments were selected to explore the availability of N-CM900/PMS. In addition, 1 O 2 dominated 2,4-DCP oxidation (about 60–70%), while the remaining 30–40% was contributed by the mediated electron transfer and N-CM-PMS*. Mechanism investigation suggested that graphitic nitrogen, the electron-rich ketonic groups and defects play a pivotal role in peroxymonosulfate activation . Combined with byproducts analysis, small-molecule acids, H 2 O and CO 2 were predominant. Overall, this study unveils a novel direction for the design of high nitrogen-doped carbon materials and improves the understanding of the coexistence of multiple mechanisms in the activation of PMS by nitrogen-doped carbon materials.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）