Adsorption of heavy metals on activated carbons is influenced by various factors that must be controlled. This study investigates the optimal conditions for removal lead on activated carbon using experimental designs. Thus influence of three parameters (pH, lead concentration and activated carbon) on adsorption rate was studied. Activated carbons was prepared from coconuts shells of Côte d’Ivoire by using chemical activation method. PH, lead concentration and coal nature are the factors taken into account in the two-level complete factorial plan used for optimization. Values of lead elimination rate are between 87 % and 96 % thus indicating the pertinence of the choice of the experimental domain. Moreover, two of the three factors; pH and lead concentration have a significant influence on the lead removal rate. Also, interactions between carbon type and lead concentration and those between pH and concentration have a significant influence on adsorption. Thus, the optimal adsorption conditions of 50 mL of lead at 150 mg / L of concentration are obtained with 0.3 g of activated carbon, at pH 6 and at a temperature of 25 ° C. Experimental designs therefore make it possible to optimize lead removal conditions from wastewater.

This study consisted in optimizing the adsorption capacity of activated carbon from the peanut shell for the removal of the yellow dye 11 (CJ 11) in solution. The active carbons are derived from the peanut shells of the subspecies hypogaea (Arachis hypogaea ssp.hypogaea) of the Virginia type derived from Mankono and subspecies fastigiata (Arachis hypogaea ssp. fastigiata) of the Spanish type from Kani. and Séguela. Peanut shells underwent pyrolysis preceded by chemical impregnation with orthophosphoric acid. The analysis of the results indicates that for the preparation of an optimal activated carbon from the Virginia sub-species hypogaea (Arachis hypogaea ssp. hypogaea) from Kani, an acid concentration of 30% are required and carbonization temperature at 600 ° C for 3 h. This active carbon, which has a predominantly acid surface (92.7% of the total surface area), has an ash content of 3.1%, a degree of activation of 24%, an iodine value of 955.04 mg / g and a surface area of 706.92 m2 / g. The adsorption tests reveal that the Spanish-derived fastigiata (Arachis hypogaea ssp. fastigiata) derived from kani adsorbs the yellow dye better than the other two. And this adsorption capacity increases with the optimal conditions of preparation.