Biosorption of Lead Ions from Aqueous Solutions Using Agricultural Waste Biosorbents from Plateau State, North Central Nigeria

Biosorption using low-cost agricultural waste materials provides an economical and environmentally sustainable approach to removing heavy metal ions from industrial wastewater, with significant potential for application in developing-country contexts where conventional treatment infrastructure is limited. This study investigates the biosorption of lead ions from aqueous solutions using dried cassava peel and groundnut husk biosorbents prepared from agricultural residues widely available in Plateau State, North Central Nigeria. Biosorbents are prepared by washing, sun-drying, grinding, and sieving to uniform particle size ranges. Batch equilibrium experiments evaluate the effects of contact time, initial lead ion concentration, biosorbent dose, pH, and temperature on removal efficiency. Lead concentrations in solution before and after treatment are measured by atomic absorption spectrophotometry. Equilibrium data are modelled using Langmuir and Freundlich isotherm equations, and kinetic data are fitted to pseudo-first-order and pseudo-second-order models. Thermodynamic parameters including Gibbs free energy, enthalpy, and entropy of adsorption are calculated to determine the spontaneity and nature of the biosorption process. Results are anticipated to demonstrate greater than eighty percent lead removal at optimised conditions. Findings establish the suitability of these local agricultural waste materials as practical low-cost biosorbents and contribute to the development of affordable heavy metal remediation technologies for small-scale industries in North Central Nigeria. Keywords: biosorption, lead ions, agricultural waste, Plateau State, heavy metal removal