Iron ion assisted photocatalytic-adsorptive removal of acid orange 52 by immobilized TiO2/polyaniline bilayer photocatalyst

Abstract

In the present work, Fe3+ ion was incorporated into polyaniline crosslinked with polyvinyl alcohol-glutaraldehyde (abbreviated as PPG) synthesized via chemical polymerization to remove acid orange 52 (AO52) dye from the solution. The use of polyvinyl alcohol-glutaraldehyde (PG) as adhesive within the synthesized PANI solution decreased the surface area from 9.16 to 3.65 m2 g−1 but the addition of iron (Fe) and silicate (Si) ions has re-increased the surface area to 13.80 m2 g−1. The optimal conditions of Fe-PPG sub-layer was found through adsorption process with varied loading and pH of AO52 solution. The adsorption characteristics of immobilized Fe-PPG showed that the adsorption of AO52 obeyed the pseudo second order kinetic and Freundlich isotherm models. Upon coating with TiO2, the presence of Fe3+ ion was observed to enhance the electron-hole separation as well as visible light response of the TiO2/PPG photocatalyst leading to improvement in photocatalytic-adsorption of AO52 dye. The TiO2/Fe-PPG was highly reusable for at least 10 cycles of continuous AO52 dye removal application.

Keywords

• Acid orange 52
• Adsorption
• Cross linking
• Metal doping
• Polyaniline