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Novel synergic combinatorial photoelectrochemical technology for degradation of trace of 2.chlorophenol in drinking water

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chinese science Bulletin 2003年第8期48卷 751-757页

作者： song qiang & qu jiuhui state key lab. of environmental aquatic chemistry, research center for eco-environmental science,{2., Beijing {3., China correspondence should be addressed to qu jiuhui (e-mail: jhqu@ ***) state key {2. of {3. aquatic chemistry Research Center for Eco-environmental Science Chinese Academy of Sciences Beijing 100085 China

A novel combinatorial photoelectrochemical (CPE) technology with combination of ultraviolet (UV)- photolysis and direct current (DC) electrolysis is studied and discussed for drinking water purification. In the self-made compositive photo-electrolysis incorporate reactor, removal rate of the 2.chlorophenol as model environmental pollutants has been investigated experimentally in terms of applied voltage, pH value, flow velocity, temperature, and aeration conditions. A primary analysis of the combinatorial photo-electric synergic effect on the degradation of organic pollut-ants has been carried out. It is found that the best perform-ance of CPE oxidation is achieved by the following condi-tions: DC voltage of 5.0 V combined with UV-2.4-raidation, near neutral of pH 8 with aeration of pure oxygen. The in-fluences of circular velocity, temperature, and initial concen-tration of the pollutant are minor. Under the optimal condi-tions, removal ratio of 2.CP is higher than 50% in 3. min, and 100% removal ratio of 2.CP (5 10-6) can be reached and TOC removal ratio reached above 90% in 2.5 h. Com-plete mineralization is achieved eventually. It shows in our investigation that under the studied conditions the synergic effect of UV photolysis and DC electrolysis on the degrada-tion of the model pollutant is remarkable and validated, which may be derived from the coexistence of mutual com-plementary mechanisms of photoelectrochemical action, and the radicals chain reactions resulted from photo activation and electrolysis excitation in the process of CPE oxidation.

关键词： 2.氯酚饮用水处理组合光电化学技术 CPE 紫外线

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Mechanism and kinetics of 2.chlorophenol degradation in drinking water by photo-electrochemical synergic effect

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science China chemistry 2003年第3期46卷 259-270页

作者： song qiang (宋强) {2. {3. (曲久辉) state key {2.ratory of {3. aquatic chemistry Research Center for Eco-Environmental Science Chinese Academy of Sciences Beijing 100085 China State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Science Chinese Academy of Sciences Beijing 100085 China

The synergic effect mechanism of photo-electrochemical oxidation is investigated in detail through reaction products and kinetics analysis in a photo-electric integral reactor with 2.chlorophenol (2.CP) as the model pollutant. A kinetics model is constructed for the combinatorial photo-electrochemical (CPE) degradation. A remarkable synergetic effect, which can significantly enhance the mineralization rate of the CPE process, is verified by the comparison of apparent kinetic constants. In the CPE process, complemental effects with multi-level and multi-pathway for pollutants degradation under our experimental conditions are speculated. It is proved that the degradation pathways are not only the simple summation of that of photolysis and electrolysis, but the formation of synergic effect through combination of several new acting approaches. The degradation efficiency is enhanced considerably by three factors, control of electrode poisoning by the UV irradiation, control of excitation and reaction trend of pollutants molecules by the UV irradiation, and control of activation effect and transfer trend by the oriented direct current (DC) electric field. An advanced oxidation system is set up through manifold of free radicals chain reactions in the CPE reactions, so that the aqueous organics can be mineralized fast and completely. It is proven by the kinetics analysis that the mineralization of organic pollutants is mainly attributed to the generation of very active hydroxyl radicals (OH@) in bulk solution from the CPE synergetic effect.

关键词： 2.chlorophenol, photo-electrochemical synergic effect, kinetics model, drinking water, microelectrolysis, UV.

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Regioselective oxidation of tetracycline by permanganate through alternating susceptible moiety and increasing electron donating ability

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Journal of environmental sciences 2020年第1期32卷 281-288页

作者： Xiaohua Jiang William AJefferson Dean song Hanyang Cheng Fengmin Li Zhimin qiang Aiqian Zhang Huijuan Liu {2. {3. College of environmental science and Engineering Ocean University of ChinaQingdao 266100China The state Agriculture Ministry lab.ratory of {2.ality&Safety Risk Assessment for Tobacco Tobacco Research InstituteChinese Academy of Agricultural SciencesQingdao 266101China key lab.ratory of Drinking Water {2. and Technology Research Center for Eco-Enuironmental SciencesChinese Academy of SciencesBeijing 100085China

Permanganate has attracted much attention in wide range of chemistry and particularly in degradation of environmental ***,few studies have discussed the feature of regioselective reactivity of permanganate with specific moiety of the target ***,we studied the reaction between permanganate and tetracycline that is an emerging micropollutant with different species containing several electron-rich *** s{2.nd-order rate constants increased from 6.0 to 9.0 and could be {3.antitatively modeled by considering the speciation of both reactants,yielding kTC0=11.7(mol/L)^-1 sec^-1,kTC-=3..7(mol/L)^-1 sec^-1,kTC2.=43.1(mol/L)^-1 sec^-1 for individual reaction *** products were then identified as the hydroxylated and demethylated *** result suggested a rate-limiting step of simple hydroxylation at the phenolic and/or alkene moieties,while the demethylation should be caused by the unavoidably formed manganese oxide via single electron *** is supported by the DFT calculation,indicating the primary oxidation of phenolic group of TC0 with activation barrier of 44.5 kcal/mol and of alkene group of TC-and TC2.with activation barriers of 44.0 and 43.4 kcal/mol,*** is in agreement with the experimental results,implying the alternation of regioselectivity associated with the deprotonation *** result was further supported by performing the Fukui function and electrostatic potential analysis,reflecting the more probable site and better electron donating tendency beneficial to the permanganate oxidation.

关键词： Permanganate oxidation of tetracycline Regioselective reactivity Rate-limiting hydroxylation step Altered susceptible moiety Increased electronegativity

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