Polyaniline Membranes for Separation and Purification of Gases, Liquids, and Electrolyte Solutions

Abstract

Abstract Conjugated polymers are excellent barriers for membrane separations because their porosity can be controlled at the molecular level through chemical doping. Polyaniline (PANI) is particularly attractive because simple acid/base doping/undoping enables a controllable level of doping that can be readily achieved using dopants of different sizes and shapes. PANI, which belongs to an important member of the family of electrically conducting polymers, has been studied extensively as a membrane due to its distinct electrochemical properties and environmental stability. Adding dopants to PANI leads to a decrease in gas permeability, while removal of these dopants would produce extremely high permeability. This review provides an overview of the use of PANI membrane in gas separation (GS), pervaporation (PV) and electrodialysis (ED) applications. Our discussion will be concerned with the utility of PANI as a homopolymer, blend and composite membrane, discussing a considerable amount of background information on their developments and applications. Various modifications of PANI as efficient membranes and their future prospects in membrane separation and purification technology are discussed.