紫外增强KMnO_(4)氧化电镀废水中铜-有机络合物

UV-enhanced KMnO_(4) oxidation of copper-organic complexes in electroplating wastewater

高锰酸钾(KMnO_(4))是一种氧化性能很强且环境友好的氧化剂.本文探究了紫外(UV)增强KMnO_(4)处理氧化铜-乙二胺四乙酸有机络合物(Cu-EDTA)的动力学和机制,考察了KMnO_(4)浓度、初始溶液pH及水体中常见离子等影响因素对该体系的影响,确认了主要活性物种,并推导了Cu-EDTA的氧化路径和KMnO_(4)的作用机理.结果表明:相比单独UV或KMnO_(4)的作用,UV/KMnO_(4)能够显著增强Cu-EDTA的氧化效果.在初始pH=3.2、最佳氧化剂和污染物比例为1.2、反应时间为20 min的条件下,Cu的去除效率可以达到92%.随着KMnO_(4)浓度在0.09~0.9 mmol·L^(-1)范围内增加,Cu去除率随之增加.粹灭实验表明,与HO·相比,活性锰物种(RMnS)是UV/KMnO_(4)氧化Cu-EDTA的主要活性物种.采用超高效液相色谱-质谱联用技术分析Cu-EDTA的降解产物,表明其降解遵循脱羧反应.不同环境因子影响实验表明,强酸条件有利于反应,而随着溶液初始pH升高,Cu的去除率呈下降趋势;硝酸根离子、氯离子和硫酸根离子对Cu-EDTA降解的影响较小,天然有机物(NOM)对Cu-EDTA的降解起到明显抑制作用.另外,本文阐述了UV/KMnO_(4)的作用机制,为该技术应用于处理有机金属污染水体提供了理论支撑.

Potassium permanganate(KMnO_(4))is a highly oxidizing and environmentally friendly oxidant.This study investigated the kinetics and mechanism of ultraviolet(UV)-enhanced KMnO_(4) treatment on the oxidation of copper-ethylenediaminetetraacetic acid(Cu-EDTA).The effects of KMnO_(4) concentration,initial solution pH and common ions in water on this system were explored.The main active species were identified,and the oxidation pathway of Cu-EDTA and the mechanism of KMnO_(4) were deduced.The results showed that UV/KMnO_(4) significantly enhanced the oxidation efficiency of Cu-EDTA compared with UV or KMnO_(4) alone.When the initial pH was 3.2,the optimal oxidant to pollutant ratio was 1.2,and the reaction time was 20 min,the removal efficiency of Cu reached 92%.As the concentration of KMnO_(4) increased within the range of 0.09 mmol·L^(-1) to 0.9 mmol·L^(-1),the removal rate of Cu increased.Quenching experiments indicated that compared to HO·,the reactive manganese species(RMnS)were the main active species for UV/KMnO_(4) oxidation of Cu-EDTA.The degradation products of Cu-EDTA were analyzed by ultra-high performance liquid chromatography-mass spectrometry(UHPLC-MS).The results showed that the degradation followed decarboxylation reaction.The experiments of different environmental factors indicated that strong acid condition was favorable to the reaction,but with the increase of initial pH of solution,the removal rate of Cu decreased.Nitrate ions,chloride ions,and sulfate ions had little effect on the degradation of Cu-EDTA,while natural organic matter(NOM)significantly inhibited the degradation of Cu-EDTA.Furthermore,this study elucidated the mechanism of UV/KMnO_(4),which provided theoretical support for the application of this technology in treating organic metal-polluted water.