EDTA强化nZVI/PS降解地下水中1,2-二氯乙烷的作用机制及影响因素  

Mechanism and influencing factors of 1,2-dichloroethane degradation in groundwater by EDTA-enhanced nZVI/PS

作　　者：黄煜韬 孟宪荣[2] 许伟[2] 吴建生 许晓路[3] 吴锦平 刘阳 施维林[1] HUANG Yutao;MENG Xianrong;XU Wei;WU Jiansheng;XU Xiaolu;WU Jinping;LIU Yang;SHI Weilin(School of Environmental Science and Engineering,Suzhou University of Science and Technology,Suzhou 215000,China;Suzhou Institute of Environmental Sciences,Suzhou 215000,China;School of Biological and Environmental Engineering,Zhejiang Shuren University,Hangzhou 310000,China;Environmental Protection Office of Bacheng Town,Kunshan City,Kunshan 215311,China;Suzhou Yifante Environmental Remediation Co.Ltd.,Suzhou 215000,China)

机构地区：[1]苏州科技大学环境科学与工程学院,苏州215000 [2]苏州市环境科学研究所,苏州215000 [3]浙江树人大学生物与环境工程学院,杭州310000 [4]昆山市巴城镇环境保护办公室,昆山215311 [5]苏州逸凡特环境修复有限公司,苏州215000

出　　处：《环境工程学报》2022年第3期885-893,共9页Chinese Journal of Environmental Engineering

基　　金：苏州市科技局项目(SS202036、SS202037、SS2019005)。

摘　　要：采用乙二胺四乙酸(EDTA)强化纳米零价铁(nZVI)活化过硫酸钠(PS)降解地下水中1,2-二氯乙烷(1,2-DCA)。通过分析1,2-DCA比降解率(Sq)、矿化度、1,2-DCA降解动力学及游离Fe^(2+)和Fe^(3+)质量浓度变化规律,阐明了EDTA强化效果及作用机制;考察了EDTA投加量、pH、阴阳离子对EDTA强化效果的影响。结果表明:经EDTA强化后,1,2-DCA的Sq和矿化度分别提高了21%和190%,反应速率常数提高了10.06%~22.95%,活化能降低了6.98~8.91 kJ·mol^(−1);EDTA为反应提供了弱酸性环境,促进Fe^(2+)生成,EDTA与Fe^(2+)生成螯合物,降低了Fe^(2+)与自由基反应的机率,提高了nZVI/PS的持续有效性;Sq随EDTA投加量的加大先增加后减小,EDTA投加量为1.8 mmol时Sq达到最大值214.80 mg·g^(−1)。酸性环境下EDTA的强化效果更好。除外,Cl^(−)、K^(+)和HCO_(3)^(-)均抑制EDTA的强化作用,说明EDTA在实际地下水修复中可能因多种离子存在而难以达到理想的强化效果。以上研究结果可为EDTA强化nZVI/PS降解地下水中1,2-DCA提供参考。Ethylenediaminetetraacetic acid(EDTA)was used to strengthen nano-zero-valent iron(nZVI)activated sodium persulfate(PS)for 1,2-dichloroethane(1,2-DCA)degradation in groundwater.Through analyzing the specific degradation rate(Sq),mineralization,degradation kinetics of 1,2-DCA and mass concentration change rules of Fe 2+and Fe 3+,the enhancement effect of EDTA and its mechanism were clarified.The effects of EDTA dosage,pH,anion and cation on the strengthening effect of EDTA were investigated.The results showed that after EDTA strengthening,Sq and the degree of mineralization of 1,2-DCA increased by 21%and 190%,respectively.Reaction rate increased by about 10.06%~22.95%and activation energy decreased by 6.98~8.91 kJ·mol^(−1).EDTA provided a weak acid environment for the promotion of Fe 2+formation.Then EDTA formed a chelate with Fe^(2+)which reduced the probability of the reaction between Fe^(2+)and free radicals,and improved the sustained effectiveness of nZVI/PS.Sq first increased and then decreased with the increase of EDTA dosage.Sq reached the maximum value of 214.80 mg·g^(−1) at EDTA dosage of 1.8 mmol.The strengthening effect of EDTA was better in acidic environment.Except had a promoting effect,Cl^(−),K^(+) and HCO_(3)^(-)all inhibited the strengthening effect of EDTA,indicating that EDTA might be difficult to achieve an ideal strengthening effect in remediation of actual groundwater due to the existence of multiple ions.The research results provide basic parameters and technical supports for degradation of 1,2-DCA in groundwater by EDTA-enhanced nZVI/PS.

关 键 词：地下水 1 2-二氯乙烷 过硫酸钠高级氧化 乙二胺四乙酸强化 比降解率 

分 类 号：X703.1[环境科学与工程—环境工程]