Mineralogical and Sorption Properties of Quartzite Derived Lateritic Soil

Increasing municipal solid waste generation and associated leachate pose challenges in developing countries like Nigeria and these have prompted the search for locally available, cost-effective materials that can effectively contain contaminants. This study investigates the mineralogical, and sorption properties of quartzite-derived lateritic soil from Ado-Ekiti southwestern Nigeria, with a with the aim assessing their suitability as natural landfill liners. Lateritic soil samples derived from quartzite were collected from New Iyin Road, Ado-Ekiti, and subjected to a comprehensive suite of laboratory tests following the recommended standards. Batch sorption experiments were conducted at pH levels of 5, 7, and 9 over a range of heavy metal concentrations (10–100 mg/L) for Cd, Cr, Cu, Mn, and Pb. The soils were characterized by their pH and cation exchange capacity (CEC), revealing moderately acidic conditions (pH 5.05–5.95) and low-to-moderate CEC values (41.65–45.12 meq/100 g), indicative of high silica content and limited buffering capacity. X-ray diffraction (XRD) analysis identified quartz as the dominant mineral phase, with kaolinite and illite as the main clay minerals present, reflecting extensive weathering and laterization. The adsorption data, modeled using Adsorption isotherms, demonstrated that adsorption efficiency varied with pH and metal speciation. In particular, Cd and Pb exhibited high removal efficiencies under acidic conditions, whereas Cu and Mn showed more variable trends at different pH levels. The results underscore the complex interaction between soil mineralogy, pH, and metal adsorption behavior, suggesting that these quartzite-derived lateritic soils possess a moderate potential for use as landfill liners. However, further stabilization through chemical amendments or engineered barriers, may be necessary to optimize their contaminant retention capabilities.