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.
The study was carried out on tomatoes (Lycopersicon esculentum P. Mill) and cabbages (Brassica oleracea L. var capitata) grown in Daloa. It covered ninety samples of vegetables including 60 tomato samples and 30 samples of cabbage collected during three field campaigns in a locality in Côte d'Ivoire (Daloa). These samples were processed using a SHIMADZU brand liquid chromatograph to determine pesticide residues. The results revealed contamination of tomatoes (Lycopersicon esculentum P. Mill) and cabbages (Brassica oleracea L. var capitata). Four pesticide residues, three of which belong to the organophosphorus family (chlorpyrifos, dimethoate, profenophos) and one from the pyrethroid family, were detected in tomatoes with detection percentages of 39%, 25%, 22% and 14%. The results of the analysis also showed the presence of four other pesticides including two from the organophosphorus family (profenophos and diazinon) and two others from the Carbamate family (carbaryl and dithiocarbamate) in cabbages with a rate of detection of 10% and 27%, 10% and 53% respectively. However, the remaining pesticide levels detected in tomatoes and Daloa cabbages are all below the Codex Alimentarius Standards (MRLs).