TiO2电极光电催化氧化处理水体中的蒽

摘要

In recent decades,due to their carcinogenic,mutagenic and teratogenic potential,the removal of polycyclic aromatic hydrocarbons (PAHs) from aqueous environments has attracted much interest.In order to explore the degradation effect of PAHs in aqueous environment under a photoelectrocatalytic system,the destruction of anthracene (Ant) was investigated by using TiO2 electrode under the irradiation of UV light.The degradation abilities of Ant in the photoelectrocatalytic (PEC),photocatalytic (PC) and electrochemical oxidation (EO) systems were compared.The effects of various parameters on the degradation of Ant were estimated as well,including applied current density,initial solution pH,initial Ant concentration and humic acid (HA).The reaction rate was analyzed by using the pseudo-first order kinetics.The mechanism of degradation of Ant and the kinds of intermediates were subsequently studied.The results showed that at the same current density and reaction time and other conditions,thedegradation of PEC was higher than those in the PC and EO systems.The current density presented little effect on the degradation of Ant,and the removal efficiency was 98.5％ with current density 0.05 mA/cm2 in 30 min.Anthrone and Anthraquinone were the intermediates,and their concentrations increased first and then decreased.The initial pH had relativel yhigh effect on the generation of Anthraquinone.The initial concentration had high effect on the apparent reaction constant;when the initial concentration increased 3 times,the apparent reaction rate was reduced by nearly 44％,but the degree of the Ant degradation was less than 1％.In the presence of HA,Ant degradation was lower by 7.5％,and the apparent reaction rate was reduced by nearly 83％.%为了探究光电催化体系对水体中多环芳烃(PAHs)的降解效果,采用TiO2电极在紫外光照射下进行了光电催化氧化处理多环芳烃——Ant(蒽)的研究.分别比较了光电催化(PEC)、光催化(PC)和电化学氧化(EC)体系对Ant的降解效果.并探究了电流密度、初始pH、初始ρ(Ant)和腐植酸(HA)等对Ant降解效果的影响;同时,采用伪一级动力学对降解反应速率进行了拟合分析并对中间产物的含量及Ant的降解机理进行了研究.结果表明:在相同电流密度和反应时间等条件下,PEC体系对Ant的降解率均高于PC和EO体系;电流密度对Ant降解影响不大,在电流密度为0.05 mA/cm2条件下,反应30 min后,Ant的降解率能达到98.5％,体系中中间产物有蒽酮(AT)、蒽醌(AQ)等物质,其浓度呈现先增加后降低的趋势;初始pH对中间产物AQ的生成影响较大;初始浓度对反应速率影响较大,初始浓度增加3倍,反应速率降低了近44％,但Ant的降解率相差不到1％;HA的存在使得Ant降解率降低了7.5％,反应速率降低了近83％.