Characterization of Local Clay from Burkina Faso for the Removal of Lead from Groundwater

The contamination of water resources by trace metals (TMs), particularly lead (Pb2+), is a significant public health and environmental concern, especially in areas where access to modern treatment technologies is limited. The adsorbent material used is KOM clay, collected from Kombissiri, near Ouagadougou, in Burkina Faso, and characterized using various physicochemical techniques. Characterization enabled the quantification of the minerals present in KOM: quartz (27%), montmorillonite (25%), illite (21%), kaolinite (18%), and goethite (6%). This characterization highlighted the adsorbent properties of montmorillonite clay, which endow it with an interesting adsorption capacity for removing lead from groundwater. Adsorption tests carried out in synthetic batch solutions showed that the adsorption capacity of lead (Pb2+) is influenced by various parameters, namely kinetics, dose effect, and initial concentration effect. The kinetic study showed that contact time is reached after 3 hours. The data were consistent with the pseudo-second-order model. The results obtained by dose effect show that clay could remove up to 98.03%, or 4.9 mg/g, for an optimal adsorbent dose of 10 g/L. The isotherm models obtained from the data on the effect of the initial concentration on the adsorption of lead Pb2+ confirmed that the adsorption of lead Pb2+ is monolayer adsorption. This result reflects a strong affinity between lead and the active sites of montmorillonite and confirms the value of this natural material as an economical and sustainable solution for treating water polluted by trace metals.