Synthesis of Polyaniline/Titanium Dioxide/Carboxymethyl Cellulose Composites as Ternary Adsorbent for Nickel Removal

Abstract

Conductive polymer-based adsorbent such as polyaniline has a great potential in replacing conventional adsorbent to remove heavy metal. In this research, different polyanilines were synthesized by modifying synthesis methods and parameters in expectance to yield different properties, which may affect nickel removal efficiency. Besides, titanium dioxide and carboxymethyl cellulose were added to further improve Ni removal efficiency. All synthesized samples were examined with FTIR and UV–Vis to confirm their chemical structures and oxidation states. The electrical conductivities of the samples were measured on a four-point probe and their crystallographic information and incorporation of metal oxide were confirmed using XRD and EDX respectively. The samples’ thermal stability and morphologies were investigated using TGA and FESEM respectively. Among the different morphologies obtained, nanotubes showed highest Ni removal efficiency of 31.250% as its longitudinal structure allowed easier access of polyaniline active sites to interact with Ni ions. With the incorporation of TiO₂ and carboxymethyl cellulose, the Ni removal efficiency of polyaniline/TiO₂/carboxymethyl cellulose significantly improved to 66.8% with TiO₂ improving the charge transport network and surface roughness while carboxymethyl cellulose provides additional active sites and improved hydrophilicity for the transfer of Ni ions from solution to adsorbent surface.