气相甲苯光催化降解反应动力学及机理

Abstract

以紫外光为光源,锐钛矿型TIO2为催化剂,研究了气相甲苯光催化降解过程,并探讨了降解机理.结果表明,甲苯光催化降解过程符合一级反应动力学方程,甲苯初始浓度越高,反应速率常数越小.甲苯光催化降解的主要中间产物为己烷和苯.在紫外光和TIO2作用下,甲苯经脱甲基反应生成苯和甲基,甲基可与甲苯分解产生的3-戊烯炔生成2,4-己二烯,经加氢转化为己烷.

Chemical kinetics and intermediates in photocatalytic degradation of gaseous toluene were investigated under UV irradiation with TiO2.According to the intermediates analyzed by GC/MS, possible mechanism for photocatalytic degradation of gaseous toluene was proposed.The result showed that the degradation of toluene followed the first-order chemical kinetics.With the increase of initial toluene concentration, the reaction rate of photocatalytic degradation of toluene increased and the reaction rate decreased.The main intermediates of photocatalytic degradation were hexane and benzene.Toluene could be converted into benzene and methyl by demethylation with UV irradiation and TiO2.Methyl reacted with 3-penta-eneyne produced by dissociation of toluene into 2,4-hexadiene, which could produce hexane by hydrogenation.