钒氧化物对过硫酸盐降解2,4-二硝基甲苯的影响  

Impacts of vanadium oxide on the degradation of 2,4-dinitrotoluene by persulfate

作　　者：常文杰 李晓东[1] 沈佳伦 孙宗全 马福俊[1,2] 谷庆宝 CHANG Wenjie;LI Xiaodong;SHEN Jialun;SUN Zongquan;MA Fujun;GU Qingbao(State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences,Beijing 100012,China;National Engineering Laboratory for Site Remediation Technologies,Beijing 100015,China)

机构地区：[1]中国环境科学研究院,环境基准与风险评估国家重点实验室,北京100012 [2]污染场地安全修复技术国家工程实验室,北京100015

出　　处：《环境工程学报》2021年第6期2000-2007,共8页Chinese Journal of Environmental Engineering

基　　金：污染场地安全修复技术国家工程实验室开放基金项目(NEL-SRT201706)。

摘　　要：钒是土壤中普遍存在的微量元素,钒氧化物对过硫酸盐(PS)降解有机污染物的影响及作用机制目前还不明确。以三氧化二钒(V_(2)O_(3))、二氧化钒(VO_(2))和五氧化二钒(V_(2)O_(5))为研究对象,探究了不同PS/钒氧化物体系对2,4-二硝基甲苯(2,4-DNT)的降解性能和相关机理。结果表明:不同PS/钒氧化物体系对2,4-DNT的降解性能具有显著差别,其中PS/V_(2)O_(3)体系表现出较强的氧化能力;在反应10 h后,PS/V_(2)O_(3)体系中2,4-DNT的降解率为77.2%,且准一级动力学模型可以很好地描述PS/V_(2)O_(3)体系对2,4-DNT的降解过程。电子自旋共振分析和自由基淬灭实验结果表明,羟基自由基是降解2,4-DNT的主要自由基。V_(2)O_(3)浓度、PS浓度和初始pH是影响PS/V_(2)O_(3)体系降解2,4-DNT的重要因素。2,4-DNT的降解率随V_(2)O_(3)含量升高而先升高后降低,在V_(2)O_(3)为5.0 mmol·L^(-1)时,2,4-DNT的降解率最高(91.70%);随着PS浓度的升高,在PS/V_(2)O_(3)体系中2,4-DNT的降解率亦显著提升;当初始pH分别为3.0、5.0、7.0和9.0时,反应10 h后,V_(2)O_(3)活化PS对2,4-DNT的降解率分别为85.91%、80.07%、80.72%和85.72%。以上研究结果可为进一步明确土壤和地下水基质对过硫酸盐原位化学氧化的影响提供参考。Vanadium is a common trace element in soil;the effects and mechanisms of vanadium oxides on organic degradation by activated persulfate(PS)are still unclear.In this study,the vanadium trioxide(V_(2)O_(3)),vanadium dioxide(VO_(2)),and vanadium pentoxide(V_(2)O_(5))were selected to investigate the performance and related mechanism of 2,4-dinitrotoluene(2,4-DNT)degradation by the PS/V_(2)O_(3),PS/VO_(2),and PS/V_(2)O_(5) systems.The results showed that these three systems had significant different performance of degradation,and the PS/V_(2)O_(3) system presented stronger oxidation capacity than other two systems.When the reaction time was 10 h,the degradation efficiency of 2,4-DNT was 77.2%,and its degradation kinetics could be well fitted by the pseudo-first model.The electron spin resonance analysis and quenching experiments indicated that hydroxyl radicals were the dominant reactive species for 2,4-DNT degradation by PS/V_(2)O_(3) oxidation.V_(2)O_(3) concentration,PS concentration,and initial pH were the important factors affecting the degradation of 2,4-DNT by PS/V_(2)O_(3) oxidation.The degradation efficiency of 2,4-DNT first increased and then decreased with the increase of V_(2)O_(3) concentration,and the degradation efficiency of 2,4-DNT reached the highest value of 91.70% at 5.0 mmol·L^(-1) V_(2)O_(3);The degradation of 2,4-DNT in the PS/V_(2)O_(3) system increased significantly with the increase of PS concentration.At the initial pH of 3.0,5.0,7.0 and 9.0,the degradation efficiencies of 2,4-DNT by 10 h oxidation reaction with V_(2)O_(3) activated PS were 85.91%,80.07%,80.72% and 85.72%,respectively.The results provide a theoretical basis for further clarifying the effects of soil and groundwater substrates on in situ chemical oxidation of persulfate.

关 键 词：土壤修复 钒氧化物 过硫酸盐 2 4-DNT 羟基自由基 

分 类 号：X52[环境科学与工程—环境工程]