A natural clayey adsorbent for selective removal of lead from aqueous solutions

• Tunisian natural adsorbents have high adsorptive capacities for heavy metals.
• Selective removal of lead ions over other metals by natural adsorbents was achieved.
• The removal kinetics was governed by the pseudo-second-order model.
• The studied material achieved better removal efficiency than other natural adsorbents.

Natural clay minerals are an inherently colorless class of materials, which have long been known for their versatility as adsorbents due to their interchange capacity, large catalytic support, great surface area, and low cost. Herein, we have reported the use of natural clay, collected from the Gabes area, southern Tunisia (Early Cretaceous) for selectively capturing of lead ions from aqueous environments. Our results showed that natural clay samples were mainly composed of silica, alumina, iron and magnesium oxides. Adsorption data showed that the studied clay samples preferably removed substantial amounts of lead ions from water. The removal efficiency of lead ions was about 86.4 mg/g of clay and followed pseudo-second-order kinetics. More than 95% of the total adsorptive capacity occurred within 30 min. These results suggest the Early Cretaceous clays, Tunisia, turned out to be an effective natural adsorbent for capturing of lead ions from aqueous environment.