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Electrochemical Oxidation of Atrazine and Clothianidin on Bi-doped SnO2–TinO2n–1 Electrocatalytic Reactive Electrochemical Membranes

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journal contribution
posted on 21.09.2018, 00:00 by Pralay Gayen, Chen Chen, Jeremiah T. Abiade, Brian P. Chaplin
This research focused on improving mineralization rates during the advanced electrochemical oxidation treatment of agricultural water contaminants. For the first time, bismuth-doped tin oxide (BDTO) catalysts were deposited on Magnéli phase (TinO2n–1, n = 4–6) reactive electrochemical membranes (REMs). Terephthalic acid (TA) was used as a OH probe, whereas atrazine (ATZ) and clothianidin (CDN) were chosen as model agricultural water contaminants. The BDTO-deposited REMs (REM/BDTO) showed higher compound removal than the REM, due to enhanced OH production. At 3.5 V/SHE, complete mineralization of TA, ATZ, and CDN was achieved for the REM/BDTO upon a single pass in the reactor (residence time ∼3.6 s). Energy consumption for REM/BDTO was as much as 31-fold lower than the REM, with minimal values per log removal of <0.53 kWh m–3 for TA (3.5 V/SHE), <0.42 kWh m–3 for ATZ (3.0 V/SHE), and 0.83 kWh m–3 for CDN (3.0 V/SHE). Density functional theory simulations provided potential dependent activation energy profiles for ATZ, CDN, and various oxidation products. Efficient mass transfer and a reaction mechanism involving direct electron transfer and reaction with OH were responsible for the rapid and complete mineralization of ATZ and CDN at very short residence times.