土壤电动修复中可渗透反应层套电极的去偏极效应及对重金属的去除作用

项目名称： 土壤电动修复中可渗透反应层套电极的去偏极效应及对重金属的去除作用

项目编号： No.20807028

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 化学工业

项目作者： 付融冰

作者单位： 上海市环境科学研究院

项目金额： 18万元

中文摘要： 针对土壤电动修复过程中电极pH值剧烈变化（偏极现象）导致重金属在土壤中过早沉积的问题，本项目提出了一种在石墨或金属电极上套嵌沸石、零价铁等活性材料构成具有可渗透反应性能的一体式复合电极新方法，实现pH控制和重金属截获的双重目的。研究了活性材料的选取制备及电极构型；在均匀和非均匀电场中研究了可渗透反应复合电极的去偏极效应及对土壤阳离子型和阴离子型重金属的去除作用和机理；采用MATLAB软件模拟了非均匀电场条件下柱状复合电极的空间布设电场效应，并采用优化的正六边形矩阵电极对铅、镍、铜、镉及铬等典型重金属污染土壤进行了大型修复试验。结果表明，碱性或经酸化的沸石分子筛具有良好的交换吸附H+、OH-和重金属的能力，零价铁也通过化学反应消耗部分H+，并将迁移而来的重金属还原固定下来；活性材料可将土壤pH值控制在适于重金属去除的范围，根据修复目标适时更换饱和的电极，对实际污染土壤重金属的整体去除率可达90%以上。修复结束后拔出复合电极即可实现对重金属的原位去除，在应用上有"即插即拔"的便捷，极大简化了工程操作性，突破了电动修复技术迈向应用的重要一步，为重金属从土壤中分离提供了一项有实用价值的新技术。

中文关键词： 污染土壤; 电动修复;重金属; 可渗透反应复合电极; 去偏极

英文摘要： In order to solve the problem that the dramatic change of pH value (polarization phenomenon) caused premature deposition of heavy metals during soil electrokinetic remediation, this project proposed a new method to develop a new composite electrode with permeable reactive performance constituted by embedding zeolite, active zero-valent iron on graphite or metal electrodes to control pH and capture heavy metals. In this project selection and preparation of active material and electrode configuration were studied. Depolarization of permeable reactive composite electrodes and their removal effect and mechanism on soil cationic and anionic heavy metals was investigated as well. In non-uniform electric fields the spatial layout electric field effect on cylindrical composite electrodes was simulated by MATLAB. Large scale remediation experiments on the removal of typical heavy metals such as lead, nickel, copper, cadmium and chromine were carried out with optimized regular hexagonal matrix electrodes. Results showed that alkaline or acidified zeolite molecular sieve had a good ability to exchange and adsorb H+, OH- and heavy metals. Zero valent iron consumed some H+ by chemical reactions, as well as reduced and fixed migrated heavy metals. Active material could control soil pH value in the range that is suitable for heavy metal removal. In order to meet the remediation goal, saturation electrodes were replaced in time. The actual overall removal efficiency on soil heavy metals was above 90%. After remediation, composite electrodes were pulled out, and the in situ removal of heavy metals was achieved. Additionally the convenience of plug-and-play simplified the operability of this method, which is also a very important step for in-situ application of electrokinetic removal technique. This also provided a very practical new technology to separate heavy metals from soil.

英文关键词： contaminated soil; electrokinetic remediation; heveay metal; permeable reactive composite electrodes; depolarity