摘要
热活化过硫酸盐(PS)可降解有机污染物,但通常需要较高的反应温度,成为制约降解效率的关键因素之一.为提高热活化PS效率,向反应体系中加入活性炭(AC)并以对硝基苯酚(PNP)为目标污染物,考察AC强化热活化PS降解PNP的效率,分析pH值、PS浓度和AC投加量等因素对PNP降解的影响,确定最佳反应条件.结果表明,AC可以明显强化热活化PS降解PNP,在AC=1.0g/L,PS=2.0mmol/L,PNP=10.0mg/L,T=50℃和pH=3.5条件下,120min时AC/PS体系对PNP降解率可达100.00%,而PS体系对PNP降解率仅为31.69%.自由基猝灭实验表明,AC/PS/PNP体系为自由基反应,SO4•–和•OH共同参与PNP降解且以SO4•–为主导.机制分析阐明AC上的表面缺陷为活性位点,其与PS中O—O键作用导致O—O键键能降低,进而O—O在热活化下均裂形成SO4•–.PNP降解中间产物分析表明AC仅提高了热活化PS降解PNP反应速率,未改变PNP的降解路径.
Thermal activation of persulfate(PS)is an effective method for degradation of organic pollutants,but the high temperature has become restrictive factor.The effects of active carbon(AC)on the thermal activation of persulfate(PS)and the subsequent degradation of p-nitrophenol(PNP)in water was systematically investigated.The effects of critical parameters,including the initial pH,PS concentration and dose of AC were also investigated.AC could significant enhanced thermal activation of PS for high efficient degradation of PNP.The degradation efficiency of PNP reached 100.00%in AC/PS system,whereas only 31.69%in PS system with AC,PS,and PNP concentration of 1.0g/L,2.0mmol/L,and 10.0mg/L,respectively,initial pH of 3.5,temperature of 50℃and reaction time of 120min.Free radical quenching experiments demonstrated that the AC/PS/PNP system was radical reaction,and SO4•–and•OH were involved in the AC/PS/PNP system,and the SO4•–were the main radical for the PNP degradation.The mechanism analysis revealed that the defective sites on AC were involved for weakening the O-O bond in PS and subsequently cleaving O-O bond by heat to generate sulfate radical.The analysis of degradation intermediates suggested that AC could only accelerate the degradation efficiency of PNP but not alter the reaction pathway in PS systems.
作者
孙鹏
柳佳鹏
王维大
李玉梅
樊健
韩剑宏
张连科
SUN Peng;LIU Jia-peng;WANG Wei-da;LI Yu-mei;FAN Jian;HAN Jian-hong;ZHANG Lian-ke(Institute of Energy and Environment,Inner Mongolia University of Science and Technology,Baotou 014010,China)
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2020年第11期4779-4785,共7页
China Environmental Science
基金
内蒙古自然科学基金资助项目(2019LH02006)。
关键词
活性炭
过硫酸盐
对硝基苯酚
降解
表面缺陷
activated carbon
persulfate
p-nitrophenol
degradation
defective sites
