CoII–NC Catalytic Membrane for Advanced Oxidation and Mineralization of Organic Pollutants

Advanced oxidation processes (AOPs) have been extensively sought after as alternatives to physical wastewater treatment processes due to their capability to destroy pollutants rather than merely relocating them to other media. However, avoiding oxidation byproduct formation by completely oxidizing them into a benign end product, CO2, has been a difficult goal to achieve in practice. We here present an innovative catalytic membrane that efficiently activates peroxymonosulfate and mineralizes organic pollutants as polluted water passes through the pores of the membrane. We developed a hydrothermal and calcination procedure to synthesize cobalt hexacyanocobaltate (CoHC) catalysts with unsaturated, atomically isolated CoII–N–C catalytic sites. We further immobilized catalysts on the surface of a commercial ceramic membrane. We demonstrate high performance of CoHC in creating both sulfate and hydroxyl radicals as well as a confined reaction environment. The optimized catalytic membrane achieves ∼80% mineralization via single-pass treatment with less than 5 min of reaction time for a wide variety of organic pollutants in simulated domestic and industrial wastewaters. We further highlight engineering options for practical application, cost effectiveness, and mechanisms behind exceptional performance.