Kinetic and Thermodynamic Study of the Dephosphation of Wastewater by Clay Materials from Côte d’Ivoire

Phosphorus is introduced into the aquatic environment from different point sources, mainly by domestic and industrial wastewater;contributing to the eutrophication of water bodies. The most common way for wastewater dephosphation is the injection of expensive chemicals into these bodies of water. Thus, the main objective of this work was to find an alternative to chemicals by using clay materials from Côte d’Ivoire to adsorb phosphate ions from aqueous solutions. The clay samples, taken from various regions were characterized by X-ray diffraction. They have a different mineralogical composition. The influence of various parameters such as the pH of the medium, contact time, the ion force, temperature, etc. on the adsorption was studied. Adsorption is influenced by the temperature, the pH of the medium, valence of the saturated cation and the clay composition. It is described by a kinetic model of the pseudo-second order. The salt of the medium has no significant effect on the process. The thermodynamic study revealed that adsorption is spontaneous, endothermic and that it is done by electrostatic means of physical nature.