The activated carbon obtained from the shells of Macoré fruit was used as an adsorbent for the removal of dyes such as methylene blue (MB) and methyl orange (MO) from synthetic contaminated aqueous ...solutions. It holds that the adsorption is more favourable at acidic pH, with an optimum adsorption at pH = 2. At this pH, the adsorption rate is more than 98% for the two dyes. The sorption capacity was enhanced by increasing the amount of activated carbon. Above room temperature, the adsorption rates remain constant at a value of approximately 99%. The study of the adsorption kinetics indicates that the adsorption on the studied dyes follows second-order kinetics. The isotherm adsorption data were found to be described by both Langmuir and Freundlich. In addition, the thermodynamic studies revealed that the adsorption process is a favourable, endothermic and spontaneous phenomenon.
•Activated carbon was prepared from Macoré fruit shells and used for dyes removal.•Langmuir and Freundlich models fitted well the sorption process.•Maximum adsorption capacity was determined using the Langmuir isotherm.•Adsorption was markedly better in a solution containing a single dye.•Thermodynamic parameters indicated an endothermic and spontaneous physisorption.
Cette etude sinscrit dans le cadre de la recherche dadsorbants, efficaces et moins coûteux pour lelimination des ETM des eaux polluees. Elle a pour objectifs de preparer un charbon actif ...fonctionnalise a partir de coques de cafe, residus agricoles disponibles en Cote dIvoire et de tester son efficacite dans lelimination du cadmium en solution aqueuse. Les charbons actifs (CA) a base de coques de cafe ont ete prepares par activation chimique avec lhydroxyde de potassium (KOH) puis fonctionnalises par impregnation dans une solution dacide nitrique de concentration 3N suivi dun traitement thermique a 120°C. Pour determiner le pouvoir adsorbant de ces charbons actifs, les tests du nombre diodes, de la surface specifique par la methode du bleu de methylene et du pHZ ont ete realises. Les performances des charbons actifs ainsi traites (CA-HNO3) et non traites (CA) ont ete evaluees pour ladsorption du cadmium comme modele dETM et comparees lors dexperiences menees en regime discontinu et etudiees en fonction du temps de contact, de la dose de ladsorbant et de la concentration initiale en cadmium. Les cinetiques ont ete suivies avec un spectrophotometre dabsorption atomique de marque SPECTRAA 110, VARIAN et la modelisation des cinetiques pseudo-premier et second ordre a ete etudiee sur chacun des adsorbants. Les resultats de la cinetique dadsorption indiquent que le temps dequilibre est de 60 min pour les deux charbons actifs. Cependant, vu ladsorption rapide en debut de reaction, le charbon actif CA-HNO3 serait donc plus favorable et presente une meilleure capacite dadsorption du cadmium. Les donnees experimentales obtenues et celles determinees theoriquement avec les deux modeles cinetiques pseudo-premier et second ordre ont montre que le modele pseudo second ordre represente mieux ladsorption du cadmium par ces deux charbons actifs avec des coefficients de correlation R² egal a 0,99. Le charbon actif fonctionnalise revele les meilleures performances delimination du cadmium avec un taux de 60% au bout dune heure de traitement a temperature ambiante.
Polycyclic aromatic hydrocarbons (PAHs) are among the organic pollutants sought both in the various environmental compartments (water, soil, air, etc.) and in food intended for human consumption. ...They are a group of persistent organic pollutants that are potentially mutagenic and carcinogenic. Thus, the present study aims to determine the PAH levels in the flesh of local poultry also called bicycle chickens (gallus gallusdomesticus). Ten (10) composite samples of chickens were collected in Karakoro, a locality located in the department of Korhogo in the north of Cote dIvoire. After the extraction and purification steps, the samples were analyzed on a Shimadzu brand HighPerformance Liquid Chromatograph (HPLC) equipped with a fluorimetric detector. The measured PAHs, eight (8) molecules in number, are classified among the priority substances to be researched in the context of food safety (fluoranthene, pyrene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1 ,2,3-cd) pyrene, benzo (g,h,i) perylene, benzo (a) anthracene, benzo (b) fluoranthene). The results obtained showed the presence of these molecules in the samples analyzed at concentrations higher than the European Union (EU) standard for some. On the other hand, all the PAHs determined have concentrations lower than the Codex Alimentarius standard.
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.
This study proposes to follow the temporal evolution of nitrate contents of groundwater and to map their spatial distribution. For this purpose, physicochemical analyzes and statistical treatments ...were carried out on 10 boreholes and 12 wells. The nitrate distribution map is obtained using the IDW (Inverse Distance Weitling) interpolation method. Nitrate levels in the Baya watershed range from 0.5 mgL-1 to 196.2 mgL-1. Well water is richer in nitrate than drilling water with an average grade of 28.77 and 13.51 mg.L-1, respectively. Only 12% of nitrate levels are above the WHO guideline (50 mg.L-1) for drinking water. These are the waters of P3 (79.5 mg.L-1), P5 (110.8 mg.L-1) and P8 (56 mg.L-1) and F1 wells (47.1 mg. L-1) F10 (109.6 mg.L-1). In terms of time, unlike the drilling water, the nitrate concentrations of the wells of the rainy season are generally higher (33.96 mg.L-1) than that of the dry period (23.59 mg. L-1). Excessive nitrate levels are observed in the localities of Agnibilekro, Koun-fao, Tanda and the outlet of the main stream of Baya. This increase in nitrate levels is related to the geological nature of the soil and the anthropogenic pressure in the region.
The preservation and consumption of food of animal origin requires pickling, smoking or cooking techniques. In Côte d'Ivoire, particularly in Abidjan, in the communes of Abobo and Port-Bouět, the ...stripping of beef hides with fuels such as used tires, rubber debris and rubberwood is a widespread practice. The "kplo" or treated and smoked beef skin is highly prized. The same is true for the "choukouya", beef, sheep or goat meat cooked in artisanal metal ovens fuelled mainly with rubberwood in the communes of Port-Bouět and Yopougon. These practices generate fumes containing entities that are toxic to human food, including trace metal elements (TMEs), which are carcinogenic or mutagenic. The objective of this study is to assess the risks associated with the consumption of meat and offal (skins) contaminated with TMEs. A dietary frequency-based survey was conducted. Sixty (60) skin samples and 120 meat samples were taken. Analysis was performed by atomic absorption spectrophotometry. The results show that rubber wood and used tires are the most commonly used fuels. Among the metals investigated, lead had a daily exposure (6.52 µg/kg bw/d) above its ADI (3.5 µg/kg bw/d). The hazard ratio of 1.86 greater than 1 for lead indicates the occurrence of threshold adverse effects. ERIs greater than 10-5 indicate the occurrence of carcinogenic or mutagenic effects.
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