Department of Civil and Environmental Engineering, Western University, London, ON, Canada; Department of Geoscience, Aarhus University, 8000, Aarhus, Denmark.
Department of Earth and Environmental Sciences, Rutgers University-Newark, Newark, NJ, USA.
J Environ Manage. 2024 Sep;368:122111. doi: 10.1016/j.jenvman.2024.122111. Epub 2024 Aug 7.
Colloidal activated carbon (CAC) is an emerging remedial enhancement fluid that is injected into the subsurface to adsorb hazardous industrial compounds for subsequent removal. CAC-enhanced remediation relies on accurate subsurface characterization and monitoring to ensure CAC reaches intended treatment locations. The objective of this study was to assess the effectiveness of the spectral induced polarization (SIP) technique to track CAC migration within porous media and its adsorption of the chlorinated solvent, tetrachloroethylene (PCE). Dynamic column experiments were performed with cyclic injection and flow of groundwater, CAC, and PCE within porous media, and simultaneous measurements of SIP and effluent quality. Results showed an increase in both the real and imaginary conductivities of the SIP response during injection/flow of CAC within porous media. Real conductivity returned to pre-CAC levels during subsequent flushing of CAC with groundwater, which had left behind only carbon-coated soil grains; however, imaginary conductivity identified the change in polarizability due to the alterations on the grain surface. The subsequent adsorption of aqueous phase PCE did not generate a distinctive change in SIP response, mainly due to the low 50 mg/L concentrations used. Overall, this study suggests that SIP can be a valuable tool to effectively and non-invasively track the migration of injected CAC within porous media for contaminant adsorption, suggesting it can be used to enhance the implementation and management of environmental remediation programs.
胶态活性炭（CAC）是一种新兴的修复增强流体，被注入地下以吸附危险的工业化合物，以便随后进行去除。CAC 增强修复依赖于准确的地下特征描述和监测，以确保 CAC 到达预期的处理位置。本研究的目的是评估光谱感应极化（SIP）技术在跟踪多孔介质中 CAC 迁移及其对氯化溶剂四氯乙烯（PCE）的吸附方面的有效性。在多孔介质中进行了带有地下水、CAC 和 PCE 的循环注入和流动的动态柱实验，并同时进行了 SIP 和流出液质量的测量。结果表明，在多孔介质中注入/流动 CAC 期间，SIP 响应的实部和虚部电导率均增加。在随后用地下水冲洗 CAC 时，实部电导率恢复到 CAC 之前的水平，此时只留下了涂有碳的土壤颗粒；然而，虚部电导率识别出由于颗粒表面的变化而导致的极化率变化。随后吸附水相 PCE 并没有产生 SIP 响应的明显变化，主要是由于使用的浓度低至 50mg/L。总的来说，这项研究表明，SIP 可以成为一种有价值的工具，用于有效地、非侵入性地跟踪注入的 CAC 在多孔介质中的迁移，以用于污染物的吸附，这表明它可以用于增强环境修复计划的实施和管理。
