Compatibility, Gelling, and Release Kinetics of Controlled-Release Permanganate Gel (CRP-G): A Hyper-Saline, Delayed-Gelling KMnO4 Solution for Treating Large, Dilute, or Deep Plumes of Chlorinated Solvents in Aquifers

Chlorinated solvents represent a group of the most prevalent groundwater contaminants.  Once introduced into the complicated hydrologic system, these dense nonaqueous phase liquids (DNAPL) form persistent source of contamination in aquifer, often yielding large, dilute (<0.1 mg/L), or deep plumes which can extend for thousands of meters down gradient from the source.

This study aims to develop a controlled-release permanganate (MnO₄^-) gel (CRP-G), a delayed-gelling hypersaline (up to ~50 g/L) permanganate solution, which can be injected into aquifers through wells. The injected CRP-G would gradually become more viscous to form permanganate gel in situ, which could continually release MnO₄^- in a long-term and controlled manner. For this study, (i) compatibilities of available gelling agents with permanganate were characterized and (ii) various forms of CRP-G solutions were developed and tested for their gelation kinetics and MnO₄^- release kinetics. Results of this study indicated that further extending the gelation and release kinetics will provide essential knowledge required for developing a novel remedial scheme using CRP-G. This type of remedial scheme could be cost-effective for treating large, dilute, or deep plumes in the complicated aquifer system, because it may facilitate lateral spreading of oxidant, provide controlled level of oxidant within the target area over extended period of time, and would require smaller installation and operational costs.