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

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Résumé

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 goe
thite (6%). This characterization highlighted the adsorbent properties of mont
morillonite 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 influ
enced by various parameters, namely kinetics, dose effect, and initial concen
tration effect. The kinetic study showed that contact time is reached after 3
hours. The data were consistent with the pseudo-second-order model. The re
sults 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 mont
morillonite and confirms the value of this natural material as an economical
and sustainable solution for treating water polluted by trace metals.

Mots-clés

Water, Adsorption, Montmorillonite Clay, Lead, Burkina Faso