Adsorption Study of Pb ²⁺ in a Contaminated Soil Amended With Four Leguminous Husk Wastes

ABSTRACT Heavy metal toxicity has become a major threat to living organisms in recent years due to the increase in population and anthropogenic activities. The uptake of lead by the primary producers (plants) is found to affect their metabolic functions, growth, and photosynthetic activity. Globally, various soil amendments have been employed to remediate contaminants in agricultural lands. Soil amendments using food waste could be recognized as cost‐effective, sustainable, and eco‐friendly solutions for “green remediation” strategies. This study aimed to explore how some organic food waste, such as fava, lentil, pea, and soya husk, can adsorb or immobilize the soluble lead (Pb 2+ ) in contaminated soils. Therefore, samples of lead (Pb 2+ ) contaminated soil were amended with and without husk residues and first characterized for their physicochemical properties like porosity, SSA, pH, electrical conductivity, and cation exchange capacity (CEC). Factors influencing heavy metal adsorption, such as initial Pb 2+ concentration, reaction time, and amendment ratio, were assessed. Results showed that the amendments were able to increase porosity, CEC, and electrical conductivity of the soil. Results also indicate that incorporating husks into soil effectively reduces soluble Pb 2+ levels in the soil solution at different concentrations. The adsorption of Pb 2+ in the amended soil follows the Langmuir model, with R 2 of 0.99, while in the non‐amended soil, it follows both the Langmuir (0.87) and the Freundlich (0.88) models. Incorporating 5% of husks is sufficient to achieve Pb 2+ adsorption efficiency of 80%–87%. The controlled and the treated soil samples exhibited a pseudo‐second‐order kinetic model, with high correlation coefficients ( R 2 > 0.99).