PANI-based nanocomposites for the removal of dye from wastewater

Water contamination by various pollutants, such as conventional pollutants like dyes and other emerging micropollutants, is of great concern. Nowadays, there are a host of processes for the removal of dyes from contaminated water. Due to its greater surface area, mechanical properties, and thermal properties, PANI got wide acceptance. It is prepared by chemical, electrochemical, or photochemical polymerizations. Smart properties of PANI are further enhanced by adding dopants which may be inorganic or organic, like HCl, H2SO4, and nicotinic acid. Due to π conjugated electrons, PANI nanocomposites photo-catalytically degrade dye components from wastewater. However, adsorption is the most efficient and promising one. These composites become good hosts to adsorb dye components on their surface by cationic π-interaction or anionic π- interaction. The unique doping and dedoping properties of PANI change its morphology, pore size, and surface charge, enhancing the adsorbate-adsorbent interactions and the adsorption performance. The adsorption mechanism of dye on the surface of the PANI nanocomposite involves H-bonding, van der Walls interactions, covalent interactions, and electrostatic interactions. In the end, future perspectives on removing dyes using PANI are discussed.