Adsorption Mechanism of Lead on Wood/Nano-Manganese Oxide Composite

Abstract

<em>Discharge of untreated industrial wastewater containing heavy metals such as Pb²⁺ is hazardous to the environment due to their high toxicity. This study reports on the adsorption, desorption, and kinetic study on Pb²⁺ removal from aqueous solutions using wood/Nano-manganese oxide composite (WB-NMO). The optimum pH, contact time and temperature for adsorption were found to be 5.0, 4 h and 333 K, respectively. Pseudo-second-order kinetics best described the adsorption process with an initial sorption rate of 4.0 mg g min^-1, and a half-adsorption time t_1/2</em><em> of 31.6 min. Best fit for adsorption isotherm was obtained with the Brunauer-Emmett-Teller (BET) model with a maximum adsorption capacity of 213 mg/g for an initial metal concentration of 60 mg/L. Both intra-particle diffusion and film diffusion contribute to the rate-determining step. Desorption experiments with 0.5 mol/L HCl, inferred the reusability of the composite. Adsorption experiment of Pb²⁺ from industrial wastewater confirmed that the prepared WB-NMO is a promising candidate for wastewater treatment. The WB-NMO demonstrated high Pb²⁺ removal efficiency and is considered as a promising alternative and reusable composite for lead removal from contaminated effluents.</em>