| 纳米零价铁和过氧化钙联合降解土壤淋洗废液的α-HCH |
| 摘要点击 2611 全文点击 1051 投稿时间：2017-09-27 修订日期：2018-05-17 |
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| 中文关键词 土壤 纳米零价铁(nZVI) 过氧化钙 α-HCH 淋洗 类芬顿 |
| 英文关键词 soil nanoscale zero-valent iron (nZVI) CaO2 α-HCH leaching Fenton-like |
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| 中文摘要 |
| 采用纳米零价铁（nZVI）和过氧化钙（CaO2）组成非均相类芬顿试剂降解土壤淋洗废液中的α-HCH，研究其降解效能及机制.结果表明，nZVI/CaO2可在较广的pH范围内有效降解α-HCH，当nZVI和CaO2的投加量为1g·L-1，pH值为5时降解率可达93.23%.nZVI和CaO2单独或联合处理α-HCH过程均呈准一级反应动力学模式，联合处理的反应速率常数大于单独处理之和，表明两者联合降解α-HCH具有较好的协同作用.自由基淬灭实验发现，超氧自由基对降解α-HCH的贡献率远大于羟基自由基.nZVI/CaO2降解α-HCH的中间产物主要是三氯苯和氯苯，其中三氯苯呈先急剧上升后迅速降解趋势，氯苯含量较低且变化较小，因此推测α-HCH主要降解途径是先还原为三氯苯，再继续还原为氯苯或矿化为二氧化碳和水. |
| 英文摘要 |
| Nano zerovalent iron (nZVI) and CaO2 were used to construct a heterogeneous Fenton-like system to degrade α-hexachlorocyclohexane (α-HCH) in soil solution, and the degradation efficiency and mechanism were investigated. The results showed that nZVI/CaO2 can degrade α-HCH in an extensive pH range. When the dosage of nZVI and CaO2 was 1 g·L-1 and pH was 5, the degradation rate of α-HCH reached 93.23%. The degradation process of nZVI, CaO2, and nZVI/CaO2 treatments accorded with the first-order reaction kinetics model. The reaction rate constant of nZVI/CaO2 was greater than the sum of individual treatments, showing that nZVI/CaO2 has a synergistic effect on the degradation of α-HCH. Through quenching free radical experiments, the contribution rate of superoxide radicals was shown to be greater than that of hydroxyl radicals. Intermediates, including trichlorobenzene and chlorobenzene, were detected. The content of trichlorobenzene showed a sharp increase initially, and then decreased quickly. The chlorobenzene content was low and showed little change. The α-HCH in the soil washing solution was first reduced to trichlorobenzene, which was further reduced to chlorobenzene or mineralized into CO2 and water directly. |
