光电催化氧化体系降解苯胺类污染物的同步耦合反应机制研究
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摘要
以3,4-二甲基苯胺(3,4-dimethylaniline,3,4-DMA)为苯胺类污染物的代表,通过降解贡献度分析、不同影响因素下动力学公式的建立及中间产物分析来探究其在高盐光电催化氧化体系下的同步耦合反应机制.结果表明,氯类活性物质与羟基自由基对3,4-DMA 10 min降解的贡献率分别为87.55%和7.9%,UV直接氧化、阳极直接氧化、光生空穴直接氧化的作用均可忽略.在不同的初始pH值(A)、初始氯化钠浓度(B)、电流密度(C)、光照强度(D)条件下,光电体系中的光催化与电催化反应均表现出协同效应,且电催化反应占主导.4种影响因素可通过影响氯类活性物质与羟基自由基的产生来对耦合机制产生作用.根据所得动力学公式ln(c_0/c_t)=0.0042A~(-0.2422)B~(0.3378)C~(1.4742)D~(0.2300)t,4种因素对反应体系的作用强弱顺序为:电流密度(C)>初始氯化钠浓度(B)>初始pH值(A)>光照强度(D).基于GC/MS对中间产物的检测结果,提出3,4-DMA的两种可能降解路径:①3,4-DMA依次降解为3,4-二甲基苯酚、邻二甲苯、邻甲基苯甲酸、甲苯、苯甲醛、烷烃类物质、CO_2和H_2O;②3,4-DMA依次降解为含N联苯类物质、脂肪酸类物质、CO_2和H_2O.
On the basis of the analysis of degradation contribution, establishment of kinetic formulas under different influencing factors, and analysis of intermediates, the synchronous coupling degradation mechanism of 3,4-dimethylaniline(3,4-DMA), a representative aniline pollutant, in high salt photoelectrocatalytic system was investigated. Results indicated that chlorine active substances and hydroxyl radical respectively contributed 85% and 11% to the degradation rate of 3,4-DMA in 10 minutes, and the degradation of 3,4-DMA by the direct oxidation of UV, anode and photogenerated holes was negligible. Under different conditions of initial pH values(A), initial sodium chloride concentration(B), current density(C), and light intensity(D), both photocatalysis and electrocatalysis posed a synergistic effect on the degradation of 3,4-DMA and the contribution of electrocatalysis was dominant. The four factors could have certain impact on the coupling mechanism through affecting the production of chlorine active substances and hydroxyl radical. According to the obtained kinetic formula ln(c_0/c_t)=0.0042A~(-0.2422)B~(0.3378)C~(1.4742)D~(0.2300)t,the influence of the four factors followed the order: current density(C) > initial sodium chloride concentration(B) > initial pH(A) > light intensity(D). The degradation intermediates were detected via GC-MS analysis, and two possible 3,4-DMA degradation pathways were proposed as follows:① 3,4-DMA being sequentially degraded to 3,4-dimethylphenol, o-xylene, o-methylbenzoic acid, toluene, benzaldehyde, alkane, CO_2 and H_2O; ②3,4-DMA being sequentially degraded to N-containing biphenyls, fatty acids, CO_2 and H_2O.
On the basis of the analysis of degradation contribution, establishment of kinetic formulas under different influencing factors, and analysis of intermediates, the synchronous coupling degradation mechanism of 3,4-dimethylaniline(3,4-DMA), a representative aniline pollutant, in high salt photoelectrocatalytic system was investigated. Results indicated that chlorine active substances and hydroxyl radical respectively contributed 85% and 11% to the degradation rate of 3,4-DMA in 10 minutes, and the degradation of 3,4-DMA by the direct oxidation of UV, anode and photogenerated holes was negligible. Under different conditions of initial pH values(A), initial sodium chloride concentration(B), current density(C), and light intensity(D), both photocatalysis and electrocatalysis posed a synergistic effect on the degradation of 3,4-DMA and the contribution of electrocatalysis was dominant. The four factors could have certain impact on the coupling mechanism through affecting the production of chlorine active substances and hydroxyl radical. According to the obtained kinetic formula ln(c_0/c_t)=0.0042A~(-0.2422)B~(0.3378)C~(1.4742)D~(0.2300)t,the influence of the four factors followed the order: current density(C) > initial sodium chloride concentration(B) > initial pH(A) > light intensity(D). The degradation intermediates were detected via GC-MS analysis, and two possible 3,4-DMA degradation pathways were proposed as follows:① 3,4-DMA being sequentially degraded to 3,4-dimethylphenol, o-xylene, o-methylbenzoic acid, toluene, benzaldehyde, alkane, CO_2 and H_2O; ②3,4-DMA being sequentially degraded to N-containing biphenyls, fatty acids, CO_2 and H_2O.
引文
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Bustillo-Lecompte C F,Kakar D,Mehrvar M,2018.Photochemical treatment of benzene,toluene,ethylbenzene,and xylenes (BTEX) in aqueous solutions using advanced oxidation processes:Towards a cleaner production in the petroleum refining and petrochemical industries[J].Journal of Cleaner Production,186:609-617
Cui Y H,Feng Y J,Liu J,et al.2012.Comparison of various organic compounds destruction on rare earths doped Ti/Sb-SnO2 electrodes[J].J Hazard Mater,239-240(4):225-232
Doudrick K,Yang T,Hristovski K,et al.2013.Photocatalytic nitrate reduction in water:Managing the hole scavenger and reaction by-product selectivity[J].Applied Catalysis B:Environmental,136(1):40-47
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范崇政,肖建平,丁延伟.2001.纳米TiO2的制备与光催化反应研究进展[J].科学通报,46(4):265
冯炜.2010.纳米晶体TiO2制备、活性及光催化降解1-萘酚废水路径研究[D].天津:天津大学
Gómez J L,León G,Hidalgo A M,et al.2009.Application of reverse osmosis to remove aniline from wastewater[J].Desalination,245(1/3):687-693
Jia H,Zhao J,Fan X,et al.2012.Photodegradation of phenanthrene on cation-modified clays under visible light[J].Applied Catalysis B:Environmental,123-124(7):43-51
Kormann C.1991.Photolysis of chloroform and other organic molecules in aqueous TiO2 suspensions[J].Environmental Science and Technology,25(3):494-500
Liao W,Zhang Y,Zhang M,et al.2013.Photoelectrocatalytic degradation of microcystin-LR using Ag/AgCl/TiO2 nanotube arrays electrode under visible light irradiation[J].Chemical Engineering Journal,231(6501):455-463
刘仁龙.2004.纳米TiO2光催化氧化处理苯酚水溶液的研究[D].重庆:重庆大学
刘艳彪.2011 新型电极材料光/电催化降解有机污染物及污染物化学能的综合利用[D].上海:上海交通大学
Ma J,Yang M,Sun Y,et al.2014.Fabrication of Ag/TiO2 nanotube array with enhanced photo-catalytic degradation of aqueous organic pollutant[J].Physica E:Low-dimensional Systems and Nanostructures,58(1):24-29
Marci G,Addamo M,Augugliaro V,et al.2003.Photocatalytic oxidation of toluene on irradiated TiO2:comparison of degradation performance in humidified air,in water and in water containing a zwitterionic surfactant[J].Journal of Photochemistry and Photobiology A:Chemistry,160(1/2):105-114
Pelaez M,Falaras P,Likodimos V,et al.2016.Use of selected scavengers for the determination of NF-TiO2 reactive oxygen species during the degradation of microcystin-LR under visible light irradiation[J].Journal of Molecular Catalysis A:Chemical,425(4):183-189
Pelegrini R,Peralta-Zamora P,Andrade A R D,et al.1999.Electrochemically assisted photocatalytic degradation of reactive dyes[J].Applied Catalysis B:Environmental,22(2):83-90
秦微,谢陈鑫,王震,等.2015.光电催化氧化处理高氨氮废水技术研究[J].广东化工,42(5):90-91
Varanasi L,Coscarelli E,Khaksari M,et al.2018.Transformations of dissolved organic matter induced by UV photolysis,Hydroxyl radicals,chlorine radicals,and sulfate radicals in aqueous-phase UV-Based advanced oxidation processes[J].Water Research,135:22-30
Waldner G,Pourmodjib M,Bauer R,et al.2003.Photoelectrocatalytic degradation of 4-chlorophenol and oxalic acid on titanium dioxide electrodes[J].Chemosphere,50(8):989-998
王阿楠,袁滕,骆永明.2014.二氧化钛(P25)光催化降解二苯砷酸的研究[J].环境科学,35(10):3800-3806
Xu R,Li J,Wang J,et al.2010.Photocatalytic degradation of organic dyes under solar light irradiation combined with Er3+:YAlO3/Fe- and co-doped TiO2 coated composites[J].Solar Energy Materials and Solar Cells,94(6):1157-1165
杨唯艺,李孟,张倩,等.2018.K2FeO4氧化降解3,4-二甲基苯胺的机理研究[J].中国环境科学,38(5):1744-1751
杨晓芬,赵美萍,李元宗,等.2002.水中苯胺类化合物的分光光度法测定[J].分析化学,30(5):540-543
张丽.2014.可见光响应型LaTaON2光阳极及其光电化学分解水性能研究[D].南京:南京大学
周文敏,傅德黔,孙宗光.1990.水中优先控制污染物黑名单[J].中国环境监测,(4):3-5
Augugliaro V,Loddo V,Marci G,et al.2000.Photocatalytic degradation of toluene in aqueous suspensions of polycrystalline TiO2 in the presence of the surfactant tetradecyldimethylamino-oxide[J].Studies in Surface Science & Catalysis,130(14):1973-1978
Bustillo-Lecompte C F,Kakar D,Mehrvar M,2018.Photochemical treatment of benzene,toluene,ethylbenzene,and xylenes (BTEX) in aqueous solutions using advanced oxidation processes:Towards a cleaner production in the petroleum refining and petrochemical industries[J].Journal of Cleaner Production,186:609-617
Cui Y H,Feng Y J,Liu J,et al.2012.Comparison of various organic compounds destruction on rare earths doped Ti/Sb-SnO2 electrodes[J].J Hazard Mater,239-240(4):225-232
Doudrick K,Yang T,Hristovski K,et al.2013.Photocatalytic nitrate reduction in water:Managing the hole scavenger and reaction by-product selectivity[J].Applied Catalysis B:Environmental,136(1):40-47
Epstein A J,Ginder J M,Zuo F,et al.1987.Insulator-to-metal transition in polyaniline:Effect of protonation in emeraldine[J].Synthetic Metals,21(1):63-70
Chen F,Yu S,Dong X,et al.2012.High-efficient treatment of wastewater contained the carcinogen naphthylamine by electrochemical oxidation with γ-Al2O3 supported MnO2 and Sb-doped SnO2 catalyst[J].Journal of Hazardous Materials,227-228:474-479
Fan Z Y,Huang J L,Wang P,et al.2004.Kinetics of aniline oxidation with chlorine dioxide[J].Journal of Environmental Sciences,16(2):238-241
范崇政,肖建平,丁延伟.2001.纳米TiO2的制备与光催化反应研究进展[J].科学通报,46(4):265
冯炜.2010.纳米晶体TiO2制备、活性及光催化降解1-萘酚废水路径研究[D].天津:天津大学
Gómez J L,León G,Hidalgo A M,et al.2009.Application of reverse osmosis to remove aniline from wastewater[J].Desalination,245(1/3):687-693
Jia H,Zhao J,Fan X,et al.2012.Photodegradation of phenanthrene on cation-modified clays under visible light[J].Applied Catalysis B:Environmental,123-124(7):43-51
Kormann C.1991.Photolysis of chloroform and other organic molecules in aqueous TiO2 suspensions[J].Environmental Science and Technology,25(3):494-500
Liao W,Zhang Y,Zhang M,et al.2013.Photoelectrocatalytic degradation of microcystin-LR using Ag/AgCl/TiO2 nanotube arrays electrode under visible light irradiation[J].Chemical Engineering Journal,231(6501):455-463
刘仁龙.2004.纳米TiO2光催化氧化处理苯酚水溶液的研究[D].重庆:重庆大学
刘艳彪.2011 新型电极材料光/电催化降解有机污染物及污染物化学能的综合利用[D].上海:上海交通大学
Ma J,Yang M,Sun Y,et al.2014.Fabrication of Ag/TiO2 nanotube array with enhanced photo-catalytic degradation of aqueous organic pollutant[J].Physica E:Low-dimensional Systems and Nanostructures,58(1):24-29
Marci G,Addamo M,Augugliaro V,et al.2003.Photocatalytic oxidation of toluene on irradiated TiO2:comparison of degradation performance in humidified air,in water and in water containing a zwitterionic surfactant[J].Journal of Photochemistry and Photobiology A:Chemistry,160(1/2):105-114
Pelaez M,Falaras P,Likodimos V,et al.2016.Use of selected scavengers for the determination of NF-TiO2 reactive oxygen species during the degradation of microcystin-LR under visible light irradiation[J].Journal of Molecular Catalysis A:Chemical,425(4):183-189
Pelegrini R,Peralta-Zamora P,Andrade A R D,et al.1999.Electrochemically assisted photocatalytic degradation of reactive dyes[J].Applied Catalysis B:Environmental,22(2):83-90
秦微,谢陈鑫,王震,等.2015.光电催化氧化处理高氨氮废水技术研究[J].广东化工,42(5):90-91
Varanasi L,Coscarelli E,Khaksari M,et al.2018.Transformations of dissolved organic matter induced by UV photolysis,Hydroxyl radicals,chlorine radicals,and sulfate radicals in aqueous-phase UV-Based advanced oxidation processes[J].Water Research,135:22-30
Waldner G,Pourmodjib M,Bauer R,et al.2003.Photoelectrocatalytic degradation of 4-chlorophenol and oxalic acid on titanium dioxide electrodes[J].Chemosphere,50(8):989-998
王阿楠,袁滕,骆永明.2014.二氧化钛(P25)光催化降解二苯砷酸的研究[J].环境科学,35(10):3800-3806
Xu R,Li J,Wang J,et al.2010.Photocatalytic degradation of organic dyes under solar light irradiation combined with Er3+:YAlO3/Fe- and co-doped TiO2 coated composites[J].Solar Energy Materials and Solar Cells,94(6):1157-1165
杨唯艺,李孟,张倩,等.2018.K2FeO4氧化降解3,4-二甲基苯胺的机理研究[J].中国环境科学,38(5):1744-1751
杨晓芬,赵美萍,李元宗,等.2002.水中苯胺类化合物的分光光度法测定[J].分析化学,30(5):540-543
张丽.2014.可见光响应型LaTaON2光阳极及其光电化学分解水性能研究[D].南京:南京大学
周文敏,傅德黔,孙宗光.1990.水中优先控制污染物黑名单[J].中国环境监测,(4):3-5
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