title: Polyaniline-Coated Carbon Nanotube Ultrafiltration Membranes: Enhanced Anodic Stability for In Situ Cleaning and Electro-Oxidation Processes.
abstract: Electrically conducting membranes (ECMs) have been reported to be efficient in fouling prevention and destruction of aqueous chemical compounds. In the current study, highly conductive and anodically stable composite polyaniline-carbon nanotube (PANI-CNT) ultrafiltration (UF) ECMs were fabricated through a process of electropolymerization of aniline on a CNT substrate under acidic conditions. The resulting PANI-CNT UF ECMs were characterized by scanning electron microscopy, atomic force microscopy, a four-point conductivity probe, cyclic voltammetry, and contact angle goniometry. The utilization of the PANI-CNT material led to significant advantages, including: (1) increased electrical conductivity by nearly an order of magnitude; (2) increased surface hydrophilicity while not impacting membrane selectivity or permeability; and (3) greatly improved stability under anodic conditions. The membrane's anodic stability was evaluated in a pH-controlled aqueous environment under a wide range of anodic potentials using a three-electrode cell. Results indicate a significantly reduced degradation rate in comparison to a CNT-poly(vinyl alcohol) ECM under high anodic potentials. Fouling experiments conducted with bovine serum albumin demonstrated the capacity of the PANI-CNT ECMs for in situ oxidative cleaning, with membrane flux restored to its initial value under an applied potential of 3 V. Additionally, a model organic compound (methylene blue) was electrochemically transformed at high efficiency (90%) in a single pass through the anodically charged ECM.
authors.affiliation: Department of Chemical and Environmental Engineering, University of California , Riverside 92521, California, United States.
authors.forename: Wenyan
authors.initials: W
authors.lastname: Duan
authors.affiliation: Department of Chemical and Environmental Engineering, University of California , Riverside 92521, California, United States.
authors.forename: Avner
authors.initials: A
authors.lastname: Ronen
authors.affiliation: Department of Chemical and Environmental Engineering, University of California , Riverside 92521, California, United States.
authors.forename: Sharon
authors.initials: S
authors.lastname: Walker
authors.affiliation: Department of Chemical and Environmental Engineering, University of California , Riverside 92521, California, United States.
authors.forename: David
authors.initials: D
authors.lastname: Jassby
keywords: CNT; electro-oxidation; electroconductive; in situ cleaning; membrane; methylene blue; polyaniline