MANGO PEEL WASTE AS AN ADSORBENT FOR THE REMOVAL OF Pb (II) AND Cr(III)FROM AQUEOUS SOLUTIONS

Increased activities of humans, most especially industrial activities have led to the great amount of pollutants being ejected into the environment. Aquatic environments are the most affected therefore, the need for remediation. Agricultural waste was successfully utilized for the adsorption of Cr (III) and Pb (II). The adsorbent was characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) to determine the surface morphology and the functional group present for the adsorption. The removal of the two pollutants on Mango peel waste (MPW) was optimized at pollutant initial concentration of 500 mg/L, MPW dosage of 2.0 g, pH of 4.2 for Pb (II) and 4.9 for Cr (III), and contact time of 100 and 120 min for Pb (II) and Cr (III) respectively. Based on the findings from the coefficient determination, the adsorption of Pb (II) is better described by the Langmuir model (R2 = 0.998, 0.978, 0.983 and 0.976), while Cr (III) was best described by Freundlich model (R2 = 0.966, 0.996, 0.972 and 0.988) for Langmuir, Freundlich, Temkin and D-R respectively. Adsorption maximum capacity of 188.643 and 150.332 mg/g were achieved for Pb (II) and Cr (III) respectively. The Pseudo-second-order equation was the best model to describe the adsorption processes for Cr (III) ions, whereas Pseudo-First-Order model best explained the adsorption of Pb (II) ions. Thus, the applicability of MPW in respect to wastewater treatment is feasible.