超声强化零价铁/过硫酸钾体系降解2,4,6-三氯苯酚废水

摘要

2,4,6-trichlorophenol (2,4,6-TCP),as the probe pollutant,was treated by advanced oxidation technology of zero-valent iron/potassium persulfate(Fe0/PS)enhanced by ultrasound.The effects of the initial concentration,pH value,concentration of PS and the dosage of Fe0 on the degradation were studied.Based on the comparison of the reaction rate,the concentration change of ferrous ions among the different system and the identification of the types of free radicals,the preliminary degradation mechanism of the system was also explored.The results showed that the 2,4,6-TCP removal efficiency could up to 95.5％ under the conditions of initial concentration of 20mg/L,Fe0 dosage of 0.2g/L,pH value of 6and PS concentration of 0.4g/L.The first 20min reaction followed the first-order reaction kinetics equation.The sulfate radical and hydroxyl radical both existed in the combined system and the sulfate radicals play a major role in the degradation of 2,4,6-TCP.The ultrasound could significant accelerate the degradation of pollutants by accelerating the renewal of the surface of iron powder to produce more ferrous ions.%以2,4,6-三氯苯酚(2,4,6-TCP)作为目标污染物,对超声强化零价铁/过硫酸钾(Fe0/PS)的高级氧化技术进行研究,并考察了2,4,6-TCP浓度、溶液初始pH值、过硫酸钾用量、零价铁投加量等因素对2,4,6-TCP降解的影响.通过对不同体系中反应速率、亚铁离子浓度变化的比较分析以及联合体系中自由基种类鉴定,探索了体系的初步降解机理.结果表明,在2,4,6-TCP浓度为20mg/L,过硫酸钾用量为0.4g/L,零价铁投加量为0.2g/L,初始pH值为6时,2,4,6-TCP去除率可达95.5％.前20min反应符合一级反应动力学方程.超声强化零价铁/过硫酸钾体系中同时存在硫酸根自由基和羟基自由基,起主要作用的仍然是硫酸根自由基.超声波可通过加速铁粉表面的更新持续产生更多的亚铁离子,更好活化过硫酸钾来显著加速目标污染物的降解.