废水中十六烷基三甲基溴化铵的光降解动力学研究

Research on kinetics of photodegradation of CTAB in waste water

季铵盐类阳离子表面活性剂污染会对水生环境产生不利影响,研究了在紫外灯下以Fe3+为单一催化剂降解水体中阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)的降解动力学规律。实验通过测定光降解过程中CTAB质量浓度的变化,研究了Fe3+质量浓度、溶液pH对CTAB降解的影响。初步测定了降解产物,探讨了降解机理。结果表明,CTAB光降解反应符合一级反应动力学规律,在溶液pH值为2.00～3.00时,一级动力学反应常数k受pH值、Fe3+质量浓度等影响,在0.032～0.180min-1之间变化,降解产物主要有HCOOH、CO2、NO-2等,当CTAB初始质量浓度为40mg·L-1时TOC去除率在3h达到32%。研究表明UV/Fe3+法可快速有效去除废水中季铵盐类表面活性剂污染物。

Quaternary ammonium salt of cationic surfactant in aquatic environment as contamination substance would produce adverse environment effects. In this work, the oxidation of CTAB in aqueous solutions by means of Fe3＋ homogeneous photocatalysis under UV lamp was studied. Experiments was designed to determine the mass concentration of Fe3＋ and pH of solution which influence the photo-catalyse process of CTAB. The experiments indicate that the photo-catalyse process of CTAB followes the pseudo-first-order kinetics model when pH is between 2.00 and 3.00. The first order kinetics constant（k） varies from 0.032～0.180 min-1 influenced by Fe3＋. The degradation pathways is discussed based on the degradation products which are most HCOO-, CO2 and NO2-. When the initial concentration of CTAB was 40 mg·L-1, TOC removal rate reaches 32% within 3 hours, which indicated UV/Fe3＋ process could be an efficient method for oxidating cationic surfactants of quaternary ammonium compound in waste water.