Comparative adsorption study of malachite green dye on acid-activated carbon

Activated carbon produced from coconut shells has been gaining interest in wastewater treatment as a potential carbon source for adsorption with desired porosity, surface area, and stability requirements. Acid activation has been preferred for activated carbon production due to its superiority over adsorption of malachite green dye. This study involved in the acid activation of coconut shell derived carbon and its characterisation was performed to study the surface functionalities, thermal stability, textural and structural morphologies. The activated carbon was used for the adsorption of malachite green dye from aqueous solutions and with a special insight by varying contact time (20–220 min) and initial dye concentration (20–80 mg L−1) for adsorption study. Phosphoric acid-activated carbon has shown maximum adsorption capacity (Xm) of 32.787 mg g−1 at initial malachite dye concentration of 20 mg L−1 after 3 hours. All the adsorbents followed Freundlich isotherm with intra particle diffusion model as the rate-limiting step.