Removal of m-Toluidine from aqueous solution using H₃PO₄-activated carbon from Balanites aegyptiaca seeds

Environmental pollution caused by industrial activities, vehicle emissions, and improper waste disposal poses serious risks to human health and the ecosystem. This study investigates the adsorption of m-toluidine (m-T) using activated carbon derived from Balanites aegyptiaca seeds (BASC) via H₃PO₄ chemical activation. The BASC was characterized using scanning electron microscopy and Fourier transform infrared spectroscopy and analyzed for its moisture, ash, volatile matter, and carbon content. The material exhibited a high surface area of 675.0 m² g^-1, an iodine number of 581 mg g^-1, and a point of zero charge (pH_pzc) of 4.42. Batch adsorption experiments were performed to assess the effects of pH, contact time, and temperature. Results showed that adsorption efficiency increased with temperature. The adsorption behavior is favorable and followed the Temkin isotherm, pseudo-second-order kinetic model, and a three-step intraparticle diffusion mechanism. Thermodynamic analysis revealed that the adsorption process was endothermic, spontaneous, and associated with increased system entropy. These results underscore the potential of adsorption as an efficient wastewater treatment approach for eliminating organic contaminants such as m-T from actual aqueous environments.