基于均相光化学氧化的光电一体化降解对硝基苯酚的研究  

p-Nitrophenol Degradation by Homogeneous Photochemical Oxidation Combined with Electrocatalysis

作　　者：周明华[1] 吴祖成[1] 祝巨[2] 叶倩[1] 傅锦[2] 

机构地区：[1]浙江大学环境工程研究所,浙江杭州310027 [2]浙江科技学院生物与化学工程系,浙江杭州310012

出　　处：《催化学报》2002年第4期376-380,共5页

基　　金：教育部留学回国人员科研启动基金;浙江省自然科学基金 ( 2 0 0 0 43)资助项目

摘　　要：考察了模型污染物对硝基苯酚在三种均相光化学高级氧化工艺UV/H2 O2 ,UV/Fe3 + 和UV/Fe3 + /H2 O2 同电催化联合工艺下的降解 .对于COD的去除 ,三种光电联合工艺均不同程度地存在协同效应 ,其中以UV/Fe3 + 电催化联合工艺的协同效应最显著 .分析了形成协同效应的可能机理 .在UV/H2 O2 电催化联合的工艺中 ,主要为电催化副产物氧气及其间接反应产物如过氧化氢作用的结果 .而在UV/Fe3 + 和UV/Fe3 + /H2 O2 同电催化联合的工艺中 ,主要为铁离子的电化学再生 .对硝基苯酚降解的主要产物有苯酚、对苯二酚、对苯醌、4 硝基 1,2 苯二酚、1,2 ,4 苯三酚、5 硝基 1,2 ,3 苯三酚、反丁烯二酸和草酸等 ,并在此基础上提出了降解对硝基苯酚的可能历程 .光电一体化工艺提高了COD的处理效率 ,工艺简单 ,对废水治理具有很好应用前景 .Homogeneous photooxidation processes are extensively studied for treatment of toxic and bio-refractory pollutants recently, and electrochemically assisted photooxidation appears to be a trend. In this paper, the combination of electrocatalysis and homogeneous photooxidation processes of UV/H2O2, UV/Fe3+ and UV/Fe3+/H2O2(photo-Fenton) for p-nitrophenol (PNP) degradation was investigated, in order to explore if there existed synergetic effects on COD removal in the processes and to elucidate the possible mechanism. A possible pathway for PNP degradation was proposed through the intermediates identified by HPLC, IC and LC-MS. The wastewater containing PNP of 150 mg/L was treated in a cylindrical reactor, which integrated electrocatalysis and photooxidation apparatus. The UV lamp used was 8 W with main wavelength of 254 nm, and the anode was beta-PbO2 modified by fluorine resin. There existed synergetic effects on COD removal in the above three combination processes, and the process combined by UV/Fe3+ with electrocatalysis performed the best. The COD removal efficiency was in the order of UV/Fe3+/H2O2-electrocatalysis (electrophoto-Fenton), UV/Fe3+-electrocatalysis, and UV/H2O2-electrocatalysis. Under the conditions of c (H2O2) = 5 mmol/L, c (Fe3+) = 0.5 mmol/L and I = 0.5 A, the COD removal rate by single photo-Fenton and electrocatalysis was 20.6% and 3.4% respectively. However, it was 50.2% in the electrophoto-Fenton process after treatment for 30 min. In UV/H2O2-electrocatalysis process, the possible mechanism of the synergetic effects was due to generation of active species such as H2O2 being further turned into hydroxyl radicals. In UV/Fe3+-electrocatalysis process, two aspects made contribution to the synergetic effects, one is the electrochemically regeneration of ferric ion, the other one is the role of oxygen as the side-product, being further reduced to hydrogen peroxide. Besides, Fenton-like reaction is also involved in the electrophoto-Fenton process. The main intermediates during PNP degradation were p

关 键 词：光电一体化降解 均相光化学氧化 电催化 对硝基苯酚 协同效应 废水处理 光催化 

分 类 号：O643.3[理学—物理化学]