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

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.

This article was the CEPS Communication # 106. The authors dedicate this review article in honor of Professor Alan G. MacDiarmid, the University of Texas at Dallas, USA (Nobel Laureate in Chemistry, 2000), who visited CEPS in December 2004. His untiring energy to visit and inaugurate the Center of Excellence in Polymer Science at Karnatak University, Dharwad has been a great inspiration to our younger students and scientists.

Keywords:

• Polyaniline
• membrane
• gas separation
• pervaporation
• electrodialysis

Acknowledgments

The authors (Professor T.M. Aminabhavi, Dr. M. Sairam and S.K. Nataraj) thank University Grants Commission (UGC), New Delhi, India for major funding (Grant No: F1‐41/2001/CPP‐II) to establish Center of Excellence in Polymer Science (CEPS) at Karnatak University, Dharwad. Part of this work is a result of consultation project between BHEL and CEPS. We also thank Mr. G. Swaminath, AGM., BHEL, Bangalore, India.

Notes

This article was the CEPS Communication # 106. The authors dedicate this review article in honor of Professor Alan G. MacDiarmid, the University of Texas at Dallas, USA (Nobel Laureate in Chemistry, 2000), who visited CEPS in December 2004. His untiring energy to visit and inaugurate the Center of Excellence in Polymer Science at Karnatak University, Dharwad has been a great inspiration to our younger students and scientists.