Thermodynamic, isotherm and kinetic studies lead ions adsorption onto Manihot esculenta chaff surface.

The adsorption of Lead (Pb²) ions onto raw and acid-modified Manihot esculenta chaff was examined to ascertain its potential for environmental remediation. The study focused on the thermodynamics, isotherms, and kinetics of Pb² removal across various concentrations, reaction time, pH, dosage, and temperature conditions. The adsorption of Pb²⁺ onto M. esculenta chaff increased from 23.45 mg/g at 10 min to a peak of 74.03 mg/g at 150 min for the raw sample and from 26.24 mg/g at 10 min to a peak of 96.28 mg/g at 180 min for the acid-modified sample at 300 mg/L concentration. The pseudo-first-order model fits the data for raw chaff better, while those from acid-modified chaff showed an excellent fit towards the pseudo-second-order model. The data of equilibrium by the raw M. esculenta chaff indicate an excellent fit for the Langmuir isotherm model, while the Freundlich isotherm well described the acid-modified chaff data. The enthalpy change for the raw and acid-modified chaff are 23.74 kJ/mol and 44.82 kJ/mol respectively which indicates an endothermic adsorption process. The analysis of FT-IR demonstrated that lead ions interacted primarily with hydroxyl, carbonyl, and possibly aromatic groups on the cassava chaff surface. Thus, M. esculenta chaff can be engaged for the removal of lead ions from polluted water.