亚硝酸盐共存下UV/PS/CNTs降解2,6-二氯苯酚及其机理  

Degradation and mechanism of 2,6-dichlorophenol by UV/PS/CNTs in the presence of nitrite

作　　者：田孜欣 陈滢[1] 郭洪光[1] TIAN Zixin;CHEN Ying;GUO Hongguang(College of Architecture and Environment,Sichuan University,Chengdu 610000,Sichuan,China)

机构地区：[1]四川大学建筑与环境学院,四川成都610000

出　　处：《精细化工》2022年第5期988-994,1053,共8页Fine Chemicals

基　　金：国家自然科学基金(51878422,42177060)。

摘　　要：在亚硝酸盐(NO_(2)^(-))共存下采用紫外(UV)协同碳纳米管(CNTs)复合活化过硫酸盐(UV/PS/CNTs)工艺对2,6-二氯苯酚(2,6-DCP)进行降解,探究其影响因素及降解机理,考察体系循环活化效能和副产物生成情况。结果表明,对于200 mL 0.05 mmol/L 2,6-DCP水溶液,在反应时间30 min、反应温度25℃、NO_(2)^(-)0.2 mmol/L、PS投加量0.5 mmol/L、CNTs投加量50 mg/L时,UV/PS/CNTs体系对2,6-DCP降解率达95.9%。该体系中,2,6-DCP降解率随PS和CNTs投加量的增加而增大,随NO;浓度增大而减小,溶液初始pH对目标物降解呈先增大后减小趋势,pH=9时,2,6-DCP降解率为99.8%,表观反应速率常数为0.3483 min^(-1)。CNTs具有良好的循环使用性,使用5次后,2,6-DCP降解率仍可达89.0%,且在实际水体中对2,6-DCP的降解效果较好。该体系对2,6-DCP降解遵循以单线态氧为主导的非自由基氧化途径,且反应过程中生成了一氯硝基苯酚副产物。2,6-Dichlorophenol(2,6-DCP)was degraded in the presence of nitrite(NO_(2)^(-))by persulfate activated with carbon nanotubes(CNTs)under UV light irradiation(UV/PS/CNTs).Herein,the influencing factors and degradation mechanism were investigated,followed by exploration on cyclic activation potential and by-product generation.The results showed that for 200 m L 0.05 mmol/L 2,6-DCP aqueous solution,the degradation rate of 2,6-DCP by UV/PS/CNTs system was 95.9%under reaction conditions of reaction time of 30 min,reaction temperature of 25℃,NO_(2)^(-)concentration of 0.2 mmol/L,PS dosage of 0.5mmol/L,and CNTs dosage of 50 mg/L.It was also found that the degradation rate of 2,6-DCP was positively influenced by PS and CNTs dosage but negatively by NO;concentration.The effect of initial pH of solution on 2,6-DCP degradation showed a trend of first increasing and then decreasing with a degradation rate of 99.8%and an apparent reaction rate constant of 0.3483 min^(-1) at pH 9.Furthermore,CNTs exhibited good recycling performance.After used 5 times,CNTs could still lead to a degradation rate of 2,6-DCP up to 89.0%,and its degradation effect was good even in actual water system.The mechanism study suggested that the degradation of 2,6-DCP in this system followed a singlet-oxygen dominated nonradical oxidation pathway,and by-products like monochloronitrophenol were generated during the reaction.

关 键 词：亚硝酸盐 UV 过硫酸盐 碳纳米管 2 6-二氯苯酚 非自由基氧化 水处理技术 

分 类 号：X703[环境科学与工程—环境工程]