Nickel Removal from Aqueous Solution Using Chemically Treated Mahogany Sawdust as Biosorbent

Sawdust is a waste material, which is generally produced during making furniture and other necessary wood products. With a view to utilizing this waste material, a biosorbent was prepared from mahogany (Swietenia macrophylla) sawdust through simple chemical treatment and was used to remove nickel ion (Ni2+) from an aqueous solution. The adsorbent material was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis. The effects of biosorbent dosage (2∼18 g/L), pH of the tested solution (4∼10.5), contact time (up to 360 min), and temperature (298∼318 K) were studied in batchwise experiments. The maximum adsorption capacity of the treated sawdust was determined to be 13.42 mg/g at an optimum condition (sorbent dose of 15 g/L, pH of 9, and temperature of 298 K). The experimental data extrapolation revealed that the adsorption process fitted the Langmuir isotherm model and the kinetics was a pseudo-second-order kinetic model. The obtained thermodynamic parameters indicated that the adsorption reaction was spontaneous, endothermic, and random in nature. The study revealed that sawdust biosorbent has potential adsorption efficiency for nickel ion removal from an aqueous solution.