Heavy metals removal from watercourses by low cost natural Tunisian material Environmental protection

L. Aloui, F. Ayari, A. Ben Othman, M. Trabelsi-Ayadi

Clays mineral, especially smectite type, are widely used as barriers in landfills to avoid pollution of subsoil and groundwater by leachates containing heavy metals. Hence it is important to study the adsorption of metals by these kinds of clays since it’s a low cost material and frequently presented in nature; accordingly many researchers pinpoint their interest to apply this material as adsorbent to reduce heavy metals from wastewater. In this investigation, we have tried to evaluate adsorption properties of local clay, denoted ArB, collected from south of Tunisia (Stah Gafsa), to remove lead and cadmium from aqueous solution. This clay was tested at the first time to remove heavy metals for environmental protection. First of all clay was purified and characterized by several physico-chemical methods. Results approve the general smectite group of the sample with fraction of illite and kaolinite. The adsorptive properties of purified sample, Na-enriched smectite denoted ArP, in cadmium and lead annoying aqueous environment were studied in a batch adsorption system. It was found that the amount of adsorption of metal ion increased with the initial solution pH, metal ion concentration, and contact time, and with the amount of adsorbent. Adsorption isotherm show an apparent selectivity with the following order: Pb2+> Cd2+. The percentage of ion removal by ArP in certain experimental conditions can reach 98% for cadmium and 57% for lead.