摘要
研究了柠檬酸(CA)螯合Fe^(2+)活化过碳酸盐体系中投加盐酸羟胺(HAH)对三氯乙烯(TCE)的去除效果。结果发现,HAH能有效将Fe3+还原为Fe^(2+),强化TCE的去除效果。当TCE初始浓度为0.15mmol/L时,nSPC∶nFe^(2+)∶nTCE=5∶3∶1时,在CA浓度为0.5mmol/L条件下,HAH最佳投加浓度为1.5mmol/L,此时TCE去除率为99.6%。·OH对TCE降解的贡献度为79.2%,O-2·的贡献度为21.9%。HAH可减轻HCO-3对TCE降解的抑制效应,中间产物为甲酸、NO-2和NO-3。HAH利于SPC/Fe^(2+)/CA体系降解TCE,该结果可为实际TCE污染地下水修复提供技术支撑。
The impact of hydroxylamine hydrochloride（HAH）addition on the enhancement of trichloroethylene（TCE）degradation in the citric acid（CA）-chelated Fe^2＋-catalyzed sodium percarbonate（SPC）system was investigated.The effects of HAH dosage and solution martirx（Cl^-,HCO^-3 and hurmic acid）on TCE removal were examined and the results indicated that HAH promoted TCE degradation significantly by transferring Fe3＋to Fe^2＋,therefore maintaining a sustainable activation of Fe^2＋.Under the optimum molar ratio of nSPC∶nFe^2＋∶nTCE=5∶3∶1 at the initial concentration of TCE 0.15 mol/L and CA 0.50 mmol/L,the final TCE removal efficiency was 99.6%.HCO^-3 had significant inhibitory effect on the degradation of TCE,whereas the effects of Cl^-and humic acid on the degradation of TCE could be ignored.In addition,TCE removal inhibition rate of HCO^-3 were 59.9%,15.5% and 14.9%respectively when HCO^-3 concentration was all 1.0 mmol/L in SPC/Fe^2＋/TCE,SPC/Fe^2＋/CA/TCE and HAH/SPC/Fe^2＋/CA/TCE systems.The results indicated that HAH alleviated HCO-3 inhibitory effect on the degradation of TCE.Scavengers tests were also conducted to understand the roles of·OH and O^-2· on TCE degradation.The results showed that ·OH and O^-2· contributed 79.2% and 21.9% to TCE removal,respectively. The consistency of Cl^-concentration both experimentally and theoretically suggested the complete dechlorination of TCE in HAH/SPC/Fe^2＋/CA/TCE system.The intermediate products were formic acid,NO-2 and NO-3.The concentration of formic acid increased to 5.8 mg/L within60 min and then decreased to 1.4 mg/L within 120 min,meaning that the addition of HAH favors further degradation of formic acid and therefore complete mineralization of TCE.The overall results strongly confirmed the benefits of HAH amendment to TCE degradation in the SPC/Fe^2＋/CA system which provided a technical basis for practical applications in TCE contaminated groundwater remediation.
作者
臧学轲
ZANG Xue-ke(Shanghai Institute of Geological Engineering Exploration,Shanghai 200072,China;Shanghai Yaxin Construction Engineering Co.Ltd,Shanghai 200070,China)
出处
《华东理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2018年第3期454-462,共9页
Journal of East China University of Science and Technology
基金
上海市地矿工程勘察院资助项目(Gky201706)
关键词
过碳酸钠
三氯乙烯
FE^2+
盐酸羟胺
柠檬酸
地下水修复
sodium percarbonate
trichloroethylene
Fe^2＋
hydroxylamine hydrochloride
citric acid
groundwater remediation
