Graduate Institute of Environmental Engineering, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.
Graduate Institute of Environmental Engineering, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan; NTU Research Center for Future Earth, National Taiwan University, Taipei, Taiwan.
J Hazard Mater. 2022 Jun 15;432:128726. doi: 10.1016/j.jhazmat.2022.128726. Epub 2022 Mar 17.
In-situ chemical oxidation (ISCO) and permeable reactive barrier (PRB) have been used in field practices for contaminated groundwater remediation. In this lab-scale study, a novel system integrating ISCO and PRB using peroxydisulfate (PDS) as the oxidant and copper oxide (CuO) as the reactive barrier material was developed for the removal of 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP). The influences of chlorophenol concentration and flow rate on the system performance were first evaluated using synthetic solutions. The removal efficiencies of target chlorophenols were greater than 90% when sufficient PDS was supplied ([PDS]/[chlorophenol]>1). It was also found that the removal efficiencies decreased with the increasing chlorophenol concentrations (10-150 μM) and flow rates (1.8-14.4 mL/min). When three real groundwaters were employed, the removal efficiencies of 2,4-DCP and 2,4,6-TCP slightly reduced to 90% and 85%, respectively. For PCP, the removal efficiency dropped to 20% in two groundwaters with relatively high levels of alkalinity. The influences of pH and TOC were found to be insignificant for the range investigated (pH 6.5-8.7 and TOC = 0.4-1.5 mgC/L). The reduced removal efficiency could be due to the formation of weaker radicals and the stronger competition between bicarbonate ions and PDS for the activation sites on the CuO surfaces.
原位化学氧化 (ISCO) 和可渗透反应屏障 (PRB) 已在污染地下水修复的现场实践中得到应用。在这项实验室规模的研究中，开发了一种使用过一硫酸盐 (PDS) 作为氧化剂和氧化铜 (CuO) 作为反应性屏障材料的新型 ISCO 和 PRB 集成系统，用于去除 2,4-二氯苯酚 (2,4-DCP)、2,4,6-三氯苯酚 (2,4,6-TCP) 和五氯苯酚 (PCP)。首先使用合成溶液评估了氯酚浓度和流速对系统性能的影响。当供应足够的 PDS([PDS]/[氯酚]>1)时，目标氯酚的去除效率大于 90%。还发现去除效率随着氯酚浓度(10-150 μM)和流速(1.8-14.4 mL/min)的增加而降低。当使用三种实际地下水时，2,4-DCP 和 2,4,6-TCP 的去除效率略有降低，分别降至 90%和 85%。对于 PCP，在两种碱度相对较高的地下水中，去除效率降至 20%。发现 pH 和 TOC 的影响在研究范围内(6.5-8.7 pH 和 TOC = 0.4-1.5 mgC/L)并不显著。去除效率的降低可能是由于形成了较弱的自由基，以及碳酸氢根离子和 PDS 之间在 CuO 表面的活化位点上的竞争更激烈。
