Photocatalytic degradation of Basic Red dye utilizing Sol-Gel Derived TiO2 supported on montmorillonite: characterization, process and kinetic studies

Abstract

The present study deals with the investigation of photocatalytic degradation of Basic Red 46 dye (BR46) under ultraviolet ray using TiO2 supported onto montmorillonite as photocatalyst. TiO2 was prepared by sol–gel method and the sol obtained was used for heterocoagulation of Na-montmorillonite. The TiO2 photocatalyst was characterized by using Scanning Electron Microscopy (SEM). The determination of photocatalytic activity was observed as a function of initial dye concentration, pH of the dye solution and TiO2 photocatalyst dosage. Langmuir–Hinshelwood kinetic model was applied to experimental data and apparent reaction rate constant values were calculated. The highest percentage of degradation was achieved when the concentration of BR46 was at 20 ppm. The degradation of BR46 increased with an increase in catalyst dosing up to an optimum loading of 1.0 g/L. Same goes to pH where it increased with an increase in pH value up to an optimum value of pH 8. The photocatalytic degradation of BR46 shows pseudo-first order kinetics. The highest apparent rate constant, kapp was achieved at pH value of 8, which is 0.850 min-1. The kinetics evaluation on BR46 degradation was also studied to determine the rate constant, k which is 0.5903 ppm/min and adsorption equilibrium constant, K, 0.0019 ppm-1 as a function of BR46 pH.