Magnéli phases (TinO2n−1, n = 4 to 10) can be used as anodic and cathodic reactive electrochemical membranes (REMs) for water treatment due to their high conductivities, mechanical and chemical stability, low preparation costs, and stability under anodic and cathodic polarization. Most of the past research in our group has focused on using the REMs for oxidative processes by taking advantage of their unique capabilities to produce hydroxyl radicals via water oxidation. This study reports on the dual use of REMs for sequential reductive-oxidative processes. REMs were synthesized from two production methods, including mechanical pressing of Ti4O7 powders and gel casting of TiO2 powders, followed by thermal sintering and reduction. The removal of contaminants via electrochemical methods was performed using probe molecules and organic compounds through both direct oxidation, direct reduction, and interaction with hydroxyl radicals. Experiments were also performed for electrochemical destruction of N-nitrosodimethylamine (NDMA) in flow-through mode for single-pass sequential reduction–oxidation. Density functional theory (DFT) simulation were conducted to aid in the interpretation of experimental results and provided insights into the prevailing reaction mechanisms. Results suggest that the itegration of REM cells in series can lead to an energy efficient and technologically simple method for contaminant removal in aqueous streams.

High performance Magnéli phase reactive electrochemical membranes for oxidation and reduction of water contaminants

253rd National Meeting (2017)

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