Nangui Abrogoua University, Department of Sciences and Environmental Management, Laboratory of Environmental Sciences, 02 BP 801 Abidjan 02, Cote d’Ivoire
Coconut shells have been used as a precursor for the preparation of activated carbon by the chemical activation method. The full factorial design was applied to determine the optimum conditions for preparing the activated carbon. The factors studied were the carbonization temperature, the carbonization time and the concentration of the activating agent. Phosphoric acid was the activating agent, used for chemical activation. Planning of the experiments using the three-level full factorial design method resulted in eight trials with the iodine number as the answer to each trial. The various results obtained were analyzed using Nemrow software in order to highlight the influence of factors and their interaction. The results reveal that carbonization temperature, the carbonization time and the concentration exert a significant influence on the iodine number, when they are at their high level, respectively 600 ° C, 4h, 30% for the value of the iodine index of 445.44mg/g.
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.