Enhancing the Performance and Recyclability of Polyaniline/TiO2 Hybrid Nanocomposite by Immobilizing with Zein/Hydroxyethyl Cellulose Composites for Removal of Anionic Dyes

Abstract

Fabrication of a stable, recyclable and eco-friendly photocatalyst for dye treatment is vital in sustaining a clean ecosystem. In this regard, polyaniline/TiO2 (PANI/TiO2) photocatalyst was immobilized by zein/hydroxyethyl cellulose (zein/HEC) adhesive to enhance recyclability and catalytic activity. The blending of zein/HEC/PANI/TiO2 photocatalyst involves in situ oxidative polymerization, followed by immobilization with zein/HEC functionalized composites. The PANI/TiO2 composite was successfully grafted with the adhesive through physicochemical interaction, as evidenced by field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffractometer (XRD). The simultaneous thermal analysis (STA) results show that the photocatalyst has the best thermal stability relative to PANI and PANI/TiO2 in the recommended range of dye degradation temperature. The effect of external factors like TiO2 nanoparticle proportion, pH of the solution and catalyst dosage was studied in response to dye degradation capacity. The synthesized catalyst is efficient to degrade methyl orange in a wide range of pH. The kinetics of the catalysis reaction obeys the first order kinetics. The maximum degradation efficiency achieved was 97.9% and 84.3% in the presence and absence of light, respectively. The catalyst was easily recovered by decantation and its catalytic efficacy was more than 94% after 5 cycles. Hence, it is a promising alternative for decolourizing anionic dyes from wastewater.