Taiwan VCM Co., Kaohsiung 832, Taiwan.
Department of Civil Engineering, National Chi Nan University, Nantou County, Taiwan.
Water Res. 2014 May 1;54:149-58. doi: 10.1016/j.watres.2014.01.068. Epub 2014 Feb 11.
The objective of this study was to develop a controlled-oxidant-release technology combining in situ chemical oxidation (ISCO) and permeable reactive barrier (PRB) concepts to remediate trichloroethene (TCE)-contaminated groundwater. In this study, a potassium permanganate (KMnO4)-releasing composite (PRC) was designed for KMnO4 release. The components of this PRC included polycaprolactone (PCL), KMnO4, and starch with a weight ratio of 1.14:2:0.96. Approximately 64% (w/w) of the KMnO4 was released from the PRC after 76 days of operation in a batch system. The results indicate that the released KMnO4 could oxidize TCE effectively. The results from a column study show that the KMnO4 released from 200 g of PRC could effectively remediate 101 pore volumes (PV) of TCE-contaminated groundwater (initial TCE concentration = 0.5 mg/L) and achieve up to 95% TCE removal. The effectiveness of the PRC system was verified by the following characteristics of the effluents collected after the PRC columns (barrier): (1) decreased TCE concentrations, (2) increased ORP and pH values, and (3) increased MnO2 and KMnO4 concentrations. The results of environmental scanning electron microscope (ESEM) analysis show that the PCL and starch completely filled up the pore spaces of the PRC, creating a composite with low porosity. Secondary micro-scale capillary permeability causes the KMnO4 release, mainly through a reaction-diffusion mechanism. The PRC developed could be used as an ISCO-based passive barrier system for plume control, and it has the potential to become a cost-effective alternative for the remediation of chlorinated solvent-contaminated groundwater.
本研究旨在开发一种将原位化学氧化 (ISCO) 和可渗透反应屏障 (PRB) 概念相结合的控氧释放技术，以修复三氯乙烯 (TCE) 污染的地下水。在本研究中，设计了一种用于释放高锰酸钾 (KMnO4) 的释放型复合 (PRC)。该 PRC 的组成包括聚己内酯 (PCL)、KMnO4 和淀粉，重量比为 1.14:2:0.96。在批处理系统中运行 76 天后，PRC 中约 64% (w/w) 的 KMnO4 被释放出来。结果表明，释放的 KMnO4 可有效氧化 TCE。柱试验结果表明，从 200 g PRC 中释放的 KMnO4 可有效修复 101 倍孔隙体积 (PV) 的 TCE 污染地下水（初始 TCE 浓度为 0.5 mg/L），并实现高达 95%的 TCE 去除率。通过从 PRC 柱（屏障）收集的流出物的以下特性验证了 PRC 系统的有效性：(1) TCE 浓度降低，(2) ORP 和 pH 值增加，以及 (3) MnO2 和 KMnO4 浓度增加。环境扫描电子显微镜 (ESEM) 分析结果表明，PCL 和淀粉完全填满了 PRC 的孔隙空间，形成了一种低孔隙率的复合材料。二次微观毛细渗透率导致 KMnO4 释放，主要通过反应-扩散机制。所开发的 PRC 可用作基于 ISCO 的被动屏障系统，用于控制羽流，并且具有成为修复含氯溶剂污染地下水的经济有效替代方法的潜力。
