Photocatalytic decolorization of tartrazine using periwinkle shell ash: Effect of operational variables, kinetic and isotherm study

Abstract

The potential of a locally sourced material, periwinkle shell ash (PSA), has been explored as an effective photocatalyst for the photocatalytic decolorization of tartrazine in aqueous solution. The effect of operational variables such as irradiation time, initial dye concentration and catalyst loading on the extent of decolorization was investigated. The results show that the optimum levels of the variables were 50 minutes, 30 mg/L and 5 g/L for irradiation time, initial dye concentration and catalyst loading respectively. The pseudo first order and the Langmuir-Hinshelwood kinetic models were able to sufficiently describe the kinetics of the process. The diffusion mechanism was described by the intra-particle diffusion model, while the adsorption equilibrium was described by the Langmuir isotherm equation. The results obtained indicate that PSA can be used as an effective photocatalyst for the removal of tartrazine from aqueous solution.