Caractérisation d’une latérite naturelle du Burkina Faso en vue de l’élimination de l’arsenic (III) et l’arsenic (V) dans les eaux souterraines

Abstract

English Title: Characterization of a natural laterite of Burkina Faso for the elimination of arsenic (III) and arsenic (V) in groundwater

Arsenic is one of the major pollutants in borehole water and is an international concern because of its adverse effects on human health. In this study, a lateritic material was used for the removal of arsenic (III) and arsenic (V) in aqueous solution. The laterite used is referenced DA and characterized by different physico-chemical methods (DRX, FTIR, elementary chemical analysis, SEM, etc.). The characterization allowed the quantification of the minerals present in DA kaolinite (48.32%), hematite (13.11%), goethite (7.29%) and quartz (22.53%). It also revealed that DA has a pH value of 4.5 and has a large anion exchange capacity (AEC) ranging from 40.61 ± 2.03 to 230.80 ± 17.03 cmol.kg-1 at pH 2.42 to 10. This characterization has highlighted the adsorbent properties of the lateritic material which gives it an interesting adsorbent capacity for the removal of arsenic in groundwater. The kinetics studies have shown that equilibrium is achieved from 16 hours of contact time between the laterite and the solution containing arsenic (III and V) and their adsorption follows a pseudo-second order kinetic model. This suggests the existence of chemisorption of both arsenic species. The results of the dose effect showed an elimination reaching 0.33 mg/g As (V) or 99.69% and 0.30 mg/g As (III) or 97.30% for a dose of 0.75 g laterite.

Keywords: laterite, characterization, adsorption, elimination, arsenic, Burkina Faso.