Effective removal of Acid Blue 113 dye using overripe Cucumis sativus peel as an eco-friendly biosorbent from agricultural residue

The release of hazardous synthetic dyes into industrial effluents has emerged as an environmental problem requiring remediation. This research focused on the development of a new and environmentally-friendly process for the remediation of aqueous media containing dye. A natural biosorbent prepared from overripe Cucumis sativus peel which is a readily available local agricultural waste, was utilised for the first time to remove Acid Blue 113 dye. The biosorption performance of the biosorbent was evaluated by varying operating parameters such as initial dye concentration, pH, dosage, contact time and temperature. Fourier transformed infrared analysis confirmed the presence of hydroxyl, phenol, alcohol, carboxyl and alkyl halide groups in the biosorbent which interacted with the dye. It was determined that an improvement in biosorption capacity was observed when initial dye concentration and temperature were increased. The fit of experimental data to biosorption isotherm and kinetic models was evaluated by non-linear regression of coefficients using hybrid fractional function, root mean square error and coefficient of determination. The Langmuir model best described the equilibrium isotherm data, exhibiting maximum biosorption capacity of 59.81 mg/g. Kinetic study indicated the initial dye removal was rapid with equilibrium established within 20 min. The kinetic data were better fitted to the pseudo-second-order kinetic model than to the pseudo-first-order and Elovich kinetic models. It was also found that intraparticle diffusion played a prominent role in the rate-controlling step. The thermodynamic parameters revealed that the biosorption was endothermic, spontaneous and feasible. In conclusion, this study demonstrated that the waste biosorbent could be employed as an effective and eco-friendly alternative for the cleanup of dye-polluted aqueous media.