Reduction of Pb (II) and Cu (II) ions from synthetic wastewater utilizing magnetic adsorbent derived from banana peels: Kinetic and Isotherm analyses

The continuous advancement of human endeavours, especially through industrialization, has led to the production of substantial quantities of wastewater contaminated with heavy metals. The conversion of agricultural waste into low-cost adsorbent value-added goods has garnered interest in recent years. This work involved the preparation of MBP by the coprecipitation process, utilizing a 50:50 (w/w%) ratio of banana peels (BP) and magnetite (MF). The physicochemical properties (morphology, thermal degradation and surface area) of MBP were evaluated, and its efficacy as an adsorbent for the removal of lead (Pb) and copper (Cu) in aqueous media was examined as a function of pH (2-6), MBP dose (2-10 g/L), starting concentration (50-250 mg/L), and contact time (10-150 min). Adsorption kinetics studies indicated that equilibrium was reached after 30 min at pH 4 and at pH 5 Pb (II) and Cu (II), respectively. Five isotherms (Freundlich, Langmuir, Dubinin–Radushkevich (D–R), Redlich–Peterson (R–P) and Temkin) were utilized to evaluate the experimental results. Linear regression analysis was conducted for these models to ascertain the isotherm parameters. Additionally, the kinetic data were evaluated using pseudo-first order (PFO), pseudo-second order (PSO), Elovich, and intraparticle diffusion models. The adsorption kinetics for Cu (II) and Pb (II) adhered to the pseudo-second-order model with R 2 > 0.99, indicating a chemical character of the adsorption process. The adsorption isotherm data were precisely described using the Temkin model for Cu (II) and the Freundlich model for Pb (II), with coefficients of determination of 0.9851 and 0.9991, respectively. The maximum adsorption capacities for copper and lead (>90%) by MBP indicates its potential as an alternative adsorbent for the extraction of heavy metals from industrial effluent.