A Review on Polyaniline-based Materials Applications in Heavy Metals Removal and Catalytic Processes

•Adsorptive features of polyaniline as a scalable and stable conductive polymer.•Catalytic features of polyaniline as an environmentally friendly polymer.•Polyaniline-based materials including composites in micro and nanoscale.•Polyaniline-based composites with natural or synthetic materials.•Polyaniline as a support or protective shell for hosting catalytic active components.