Biodecolorization of Reactive Dyes Using Biochar Derived from Coconut Shell: Batch, Isotherm, Kinetic and Desorption Studies

Abstract

Abstract The present research examines the remediation of three different reactive dyes namely Reactive Orange 16 (RO16), Reactive Black 5 (RB5) Reactive Blue 19 (RB19) using biochar derived from coconut shell in an aqueous solution. The batch study showed that the pH of 2, temperature of 35 °C and biochar dosage of 1 g/L is the optimum condition for the maximum adsorption of reactive dyes. The adsorption isotherms demonstrated the highest uptake of 73.03 mg/g, 56.92 mg/g and 57.06 mg/g for RO16, RB5 and RB19 respectively. Isotherm studies predicted that the Toth model is the best fit model with a correlation coefficient greater than 0.9837. The kinetic study was carried out and results indicated that 120 minutes as an equilibrium time, the pseudo‐first‐order kinetic model and pseudo‐second‐order kinetic model were used to fit the experimental data. Finally, the reusability of the biochar was studied by using different elutants, sorbent to liquid ratio and regeneration cycles.