摘要
地下水中广泛存在的氯离子(Cl-)会在自由基作用下生成氯活性物质,进而与污染物反应可能引发新的环境风险.为研究Cl-影响过硫酸盐(PS)高级氧化技术修复苯酚污染地下水的效果及机理,采用热活化PS氧化体系考察温度、PS浓度、初始pH及Cl-浓度对苯酚降解效果的影响,结合三维荧光平行因子分析(EEM-PARAFAC)查明苯酚降解过程中体系的光谱特征,借助气相色谱-质谱联用仪识别氯代有毒副产物的数量及种类,并揭示其降解机理.结果表明:(1)反应温度的升高和PS浓度的增加均可促进苯酚的降解,且降解过程符合伪一级动力学模型.(2)Cl-的存在会加速热活化PS对苯酚的降解,其降解效率随Cl-浓度的增加而提高,当Cl-浓度为10、25和50 mmol/L时,反应5 h后苯酚降解率为100%.(3)苯酚降解过程中反应体系的荧光特征可分为4种荧光组分(C1、C2、C3和C4),Cl-存在时,C1和C2组分的荧光强度降幅更大,C3和C4组分主要为苯酚降解产物的光谱特征,其中C3组分的荧光强度随反应时间延长呈先增强后降低趋势.(4)根据质谱测试结果,推断出Cl-存在时苯酚降解的可能机理,主要包括羟基化/氧化和氯化作用,其中生成的氯代有毒副产物包括2-氯苯酚、4-氯苯酚、2,4-二氯苯酚、氯氢醌、3,5-二氯儿茶酚、2,3-二氯-2-甲基丁烷和2-氯-4-甲基-2-戊醇.研究显示,Cl-会提升热活化PS对苯酚污染地下水的修复效率,但也会因氯化作用生成氯代有毒副产物.
Chloride ion(Cl-) widely exists in groundwater and can react with free radicals to generate reactive chlorine species, which may react with pollutants in groundwater to create new environmental risks. To study the effect and mechanism of Cl-on the remediation of phenol-contaminated groundwater by persulfate(PS)-based advanced oxidation processes, the effects of temperature, PS concentration,pH, and Cl-concentration on the degradation of phenol were investigated using a thermally activated PS system. The spectral characteristics of the system during phenol degradation were investigated by excitation emission matrices-parallel factor analysis(EEM-PARAFAC). Moreover, the quantities and species of chlorinated toxic by-products were identified by gas chromatograph-mass spectrometer, and the degradation mechanism was revealed. The results showed that:(1) Degradation of phenol was promoted by increasing the reaction temperature and PS concentration, and the degradation process was in accordance with the pseudo-first-order kinetics model.(2) The presence of Cl-accelerated the degradation of phenol by thermally activated PS, and the degradation efficiency increased with the increase of Cl-concentration. When Cl-concentration was kept at 10, 25 and 50 mmol/L, the degradation rate of phenol reached 100% after 5 h of reaction.(3) The fluorescence characteristics of the reaction solution can be divided into four fluorescence components(C1, C2, C3 and C4) during the degradation of phenol. Fluorescence intensity of C1 and C2 components decreased more significantly in the presence of Cl-. C3 and C4 components are assigned to the degradation products of phenol, and the fluorescence intensity of C3 increased first and then decreased during the reaction.(4) Seven chlorinated toxic by-products(2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, chlorohydroquinone, 3,5-dichlorocatechol, 2,3-dichloro-2-methylbutane, and 2-chloro-4-methyl-2-pentanol) were detected. The degradation mechanism was proposed based mass spectrometry analysis
作者
王慧
李晓东
张玉秀
韩善萌
沈佳伦
孙宗全
马福俊
谷庆宝
WANG Hui;LI Xiaodong;ZHANG Yuxiu;HAN Shanmeng;SHEN Jialun;SUN Zongquan;MA Fujun;GU Qingbao(School of Chemical and Environmental Engineering,China University of Mining and Technology,Beijing 100083,China;State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences,Beijing 100012,China)
出处
《环境科学研究》
CAS
CSCD
北大核心
2023年第1期150-158,共9页
Research of Environmental Sciences
基金
国家重点研发计划项目(No.2019YFC1803800)
中央高校基本科研业务费专项资金资助项目(No.2022YJSHH13)。
关键词
氯离子
过硫酸盐
苯酚
平行因子分析
氯代有毒副产物
降解机理
chloride ion
persulfate
phenol
parallel factor analysis
chlorinated toxic by-products
degradation mechanism
