Effet de la variation de la température sur quelques paramètres d’équilibre d’adsorption du phosphore dans le canal de Vridi (Côte d’Ivoire)

Résumé

Effect of temperature variation on some adsorption equilibrium parameters of phosphorus in the Vridi canal (Côte d'Ivoire)

The studied adsorption models, on sediments in the case of phosphorus, indicate an exothermic adsorption with a decrease in energy and a coverage negatively correlated to medium warming. Apart from the Langmuir, Elovich and Kislev models, the models are well applicable to high temperature Vridi channel sediments (Côte d’Ivoire). The  NAP  (total  amount  of the natural exchangeable phosphorus fraction) and EPC₀ (concentration of dihydrogenophosphate in the interstitial fluid at equilibrium) values would reveal delayed exchangeable phosphorus adsorption in the heated medium. The drop of , m and  from the Freundlich and modified Freundlich models indicate a decreasing adsorption density at high temperature and pH = 7. the decline of factor m, the positive values of  in the Dubinin-Radushkevich model and those of  in the Temkin model imply a distribution of phosphorus at high attraction energy sites. The regression of  energy and the Fowler-Guggenheim constant  indicates an attraction between the adsorbed phosphates and a dissociative chemisorption probably controlled by the diffusion of  . Low values of  in the Hill-Boer model and high values of β to T = 30°C in the Dubinin-Radushkevich model indicate that the sediment has difficulty in immobilizing phosphorus. The positive  values of the Hill-Boer model indicate that the low adsorption capacity of sediments is positively correlated to temperature and negatively to pH.

Keywords: Adsorption ; Vridi channel ; Chemisorption ; Modelisation