High performance polypyrrole coated carbon-based electrocatalytic membrane for organic contaminants removal from aqueous solution

Electrocatalytic filtration process adopting the electrocatalytic membrane as both filtration membrane and active electrode showed great prospect on the organic pollutant removal from water. In this work, a high-performance metal-free polypyrrole (PPy) coated carbon-based electrocatalytic membrane (PPy@CCM) was developed through the facile and controllable electro-polymerization deposition method. Structural properties and electrochemical performance of the prepared PPy@CCM were characterized systematically. The influences of preparation parameters and operational parameters on water treatment performance of PPy@CCM were also investigated. Results indicates that the spherical PPy particles uniformly distributed on the surface of PPy@CCM. Coating with PPy particles can significantly improve the hydrophilicity and electrochemical activity of CCM, therefore PPy@CCM has lower hydraulic resistance and higher water treatment performance than CCM. The phenol and chemical oxygen demand (COD) removal rates obtained by PPy@CCM are up to 99.51% and 89.90%, respectively, under the optimal condition of 2.0 V cell potential, 2.50 g·L-1 Na2SO4, 1.5 ml·min-1 flow rate and 50 mg·L-1 phenol, and only 0.5 kWh·kgCOD-1 energy consumption is consumed. In addition, PPy@CCM also exhibits good treatment performance in different water matrixes. Moreover, PPy@CCM has good stability for several cycle operation and considerable applicability for different types of organic pollutants removal. The oxidation mechanism study reveals that PPy@CCM has both direct and indirect oxidation activity during the electrocatalytic filtration treatment, and the coating of PPy can improve the direct oxidation ability and ·OH yield of CCM.