Hydrogen Peroxide Treated Desiccated Coconut Waste as a Biosorbent in Malachite Green Removal from Aqueous Solutions

Malachite green (MG), commonly employed in the textile and dyeing sectors, is a prevalent and enduring contaminant found in wastewater and the environment. Its presence poses harmful effects to humans and aquatic organisms. This work utilised hydrogen peroxide-treated desiccated coconut waste (HPDCW) to remove MG from an aqueous solution. The HPDCW underwent characterisation utilising FTIR, SEM-EDX, pHslurry, and pHpzc.Based on the results obtained, it was found that HPDCW recorded a biosorption capacity of 211.88 mg/g, attained at a temperature of 302 K, a pH of 9, a contact period of 5 min, and a dosage of 0.02 g. MG biosorption rates accurately followed the pseudo-second-order kinetic model, while the equilibrium data presented a step-shaped isotherm model. The relatively small percentages of MG desorption observed when using distilled water and HCl (0.01 and 0.02 M) indicate that electrostatic interaction is one of the mechanisms responsible for the interaction between MG and HPDCW. There is also a possibility of the involvement of hydrogen bonding and pi-pi interactions.