Preparation and performance of polyaniline modified coal-based carbon membrane for electrochemical filtration treatment of organic wastewater

Electrochemical filtration process, in which the active conductive membranes were employed as filtration membrane and electrochemical active electrode simultaneously, exhibited great prospect on the organic wastewater treatment. In this work, an efficient metal-free polyaniline-coated coal-based carbon membrane (PANI/CM) was fabricated via a facile electrochemical polymerization deposition method. Structural properties and electrochemical properties of PANI/CM were systematically characterized via SEM, XRD, FTIR, XPS and electrochemical workstation, etc. The electrochemical filtration treatment performance of PANI/CM for organic wastewater was systematically investigated. Results showed that the PANI was successfully deposited on the coal-based carbon membrane (CM) through electrochemical oxidative polymerization deposition method. The PANI coating can effectively improve the hydrophilicity of CM. Under the optimal preparation condition, the PANI/CM achieved a high permeability of 2564.67 L.m(-2).h(-1).bar(-1) (1410.57 L.m(-2).h(-1).bar(-1 )for CM). In addition, PANI/CM possessed higher electrochemical activity and stability than CM, and the phenol and COD removal efficiencies of PANI/CM were up to > 99.32% and 84.85%, respectively, under the operation condition of 2.0 V applied voltage, 50 mg.L-1 phenol, 2.5 g.L-1 Na2SO4 and 2.0 ml.min(-1) flow rate, which were much higher than that of CM (70.12% and 63.64%, respectively). Additionally, the electrochemical oxidation mechanism of PANI/CM during the electrochemical filtration was explored, which included both indirect oxidation and direct oxidation. Furthermore, it was verified that PANI/CM also exhibited excellent applicability for different types of organic pollutants and the long-term stability.