不同活化过硫酸盐体系的机理分析及不同无机阴离子的作用:以两种有机染料为例

Mechanism analysis of different activated persulfate systems and effects of different inorganic anions:a case study of two organic dyes

高级氧化技术(AOPs)广泛应用于不同的废水处理,并目前此类技术多以羟基自由基(OH·)的产生为主.近年来,基于硫酸根自由基(SO_(4)^(-)·)的AOPs因其对有机污染物的高反应活性和对复杂环境基质的高选择性而备受关注.但是,在对各种活化方式的系统比较方面还存在一些不足,对降解途径和不同阴离子对体系的影响也缺乏研究.本文通过两种染料的降解对3种活化过硫酸盐体系进行了系统性的比较,并结合自由基捕获实验(甲醇,叔丁醇)和产物分析,研究了体系降解机制及路径.研究了4种阴离子(HCO_(3)^(-)、NO_(3)^(-)、Cl^(-)、Br^(-))对3种不同活化过硫酸盐体系降解染料的影响.结果表明,SO_(4)^(-)·与OH·在3种活化体系中对染料降解均有贡献.在热活化体系(heat-Na_(2)S_(2)O_(8))中,对染料降解起到主导作用的活性物种为SO_(4)^(-)·;在光活化体系(hv-Na_(2)S_(2)O_(8))中,对染料降解起到主导作用的活性物种为SO_(4)^(-)·与OH·;而在亚铁离子活化体系(Fe^(2+)-Na_(2)S_(2)O_(8))中,OH·对染料降解起主导作用.本文以热活化过硫酸盐体系为代表,探索了亚甲基蓝和甲基橙的降解中间体及路径.在3种活化过硫酸盐体系中,4种阴离子在不同程度上对两种染料的降解均存在抑制作用,尤其在亚铁离子活化过硫酸盐体系中,对4种阴离子的浓度变化更为敏感.

Advanced Oxidation Processes(AOPs)are widely used in different wastewater treatment.At present,most of these technologies are mainly generated according to hydroxyl radicals.In recent years,sulfate anion(SO_(4)^(-)·)based AOPs have attracted much attention due to their high reactivity to organic pollutants and high selectivity to complex environmental substrates.But the systematic comparison of various activation modes,as well as the degradation pathways and the effects of different anions on the system were lack of research.In this research,three kinds of activated persulfate systems were systematically compared through the degradation properties of the two dyes,system mechanism and degradation pathway combining radical capture experiments(methanol,tert butyl alcohol)and product analysis,and effect of four different anions(HCO_(3),Cl^(-),NO_(3),Br^(-))on three different persulfates activated systems,were carried out.The results show that SO_(4)^(-)·and OH·have different contributions in different systems,and SO_(4)^(-)·plays a leading role in the heat activation system.Both SO_(4)^(-)·and OH·play a comparable role in the hv activation system,while OH·plays a leading role in the ferrous ion activation system.Here,the heat-activated persulfate system is taken as a representative to explore the degradation intermediates and degradation pathways of methylene blue and methyl orange.Four anions can inhibit the degradation of the two dyes in the three activated persulfate systems,especially in the ferrous ion activated persulfate system,it is more sensitive to the changes of the concentration of four anions.