Sol–gel Synthesis of Kaolin/TiO2 Nanocomposites for Photocatalytic Degradation of Tannery Wastewater

Abstract

In this study, a TiO2 immobilized on kaolin was synthesized by the sol–gel route. The surface morphology, chemical and phase composition of the kaolin, synthesized TiO2 nanoparticles, and their nanocomposites were investigated using high-resolution scanning electron microscopy (HRSEM), RAMAN spectroscopy, high-resolution transmission electron microscopy (HRTEM) coupled with energy dispersive spectroscopy (EDX) and selected area electron diffraction (SAED). The influence of operational parameters such as irradiation time and catalyst dosage were evaluated. The influence of irradiation light on the degradation of chemical oxygen demand (COD) and total organic carbon (TOC) in tannery wastewater was found to be highest in 90 min, which follows a linear removal efficiency. It was evident that the photocatalytic degradation rate initially increases with catalyst loading and then decreases at high values. Almost complete decolourization was obtained upon 90 min of sunlight irradiation in the presence of kaolin/TiO2 catalyst. The satisfactory stability in recyclability of photocatalyst indicates colour, COD and TOC abatement in tannery wastewater treatment. It is clear that photocatalysis has good potential to degrade organic pollutants. Thus, there is a need to determine the degradability performance on a commercial scale.