Department of Civil and Environmental Engineering and Villanova Center for the Advancement of Sustainable Engineering, Villanova University, Villanova, Pennsylvania 19085, United States.
Environ Sci Technol. 2013 Jun 18;47(12):6554-63. doi: 10.1021/es401287e. Epub 2013 Jun 5.
This research investigates the characterization and testing of an anodic reactive electrochemical membrane (REM) for water treatment. The REM consists of a porous substoichiometric titanium dioxide (Ti4O7) tubular, ceramic electrode operated in cross-flow filtration mode. Advection-enhanced mass transfer rates, on the order of a 10-fold increase, are obtained when the REM is operated in filtration-mode, relative to a traditional flow-through mode. Oxidation experiments with model organic compounds showed that the REM was active for both direct oxidation reactions and formation of hydroxyl radicals (OH(•)). Electrochemical impedance spectroscopy data interpreted by transmission line modeling determined that the electro-active surface area was 619 times the nominal geometric surface area. Results from filtration-mode experiments with p-methoxyphenol indicate that compound removal occurred by electro-assisted adsorption and subsequent oxidation. Electro-assisted adsorption was the primary removal mechanism at potentials where OH(•) did not form. At higher potentials (>2.0 V), where OH(•) concentrations were significant, p-methoxyphenol removal occurred by a combination of electro-assisted adsorption and OH(•) oxidation. These removal mechanisms resulted in 99.9% p-methoxyphenol removal in the permeate, with calculated current efficiencies >73% at applied current densities of 0.5-1.0 mA cm(-2). These results illustrate the extreme promise of the REM for water treatment.
本研究旨在探究一种用于水处理的阳极反应性电化学膜（REM）的特性和测试。REM 由多孔亚化学计量二氧化钛（Ti4O7）管状、陶瓷电极组成，以错流过滤模式运行。与传统的流动模式相比，当 REM 以过滤模式运行时，传质速率可增强约 10 倍。用模型有机化合物进行的氧化实验表明，REM 对直接氧化反应和羟基自由基（OH(•)）的形成均具有活性。通过传输线建模对电化学阻抗谱数据的解释表明，活性表面积是名义几何表面积的 619 倍。用对甲氧基苯酚进行的过滤模式实验结果表明，化合物的去除是通过电辅助吸附和随后的氧化作用实现的。在OH(•)未形成的电位下，电辅助吸附是主要的去除机制。在更高的电位（>2.0 V）下，由于 OH(•)浓度显著，对甲氧基苯酚的去除是通过电辅助吸附和 OH(•)氧化的组合作用实现的。这些去除机制导致透过液中对甲氧基苯酚的去除率达到 99.9%，在 0.5-1.0 mA cm(-2)的应用电流密度下，计算出的电流效率>73%。这些结果说明了 REM 在水处理方面的巨大应用潜力。
