Kinetics study of some pollutantspesticides, heavy metals and dyes onto diatomaceous earth

Resumen

Environmental contamination by chemical compounds is a serious worldwide phenomenon. Thus, the removal of these compounds is considered of high importance. The objective of our work is to highlight the role of Tunisian diatomite for the elimination of pollutants from aqueous solution. Diatomite was submitted to chemical and physical modifications in order to enhance its adsorption capacity to remove toluene, Cu2+, Ni2+, methylene blue and Congo red. Our study confirmed that the adsorption phenomenon strongly depends on the initial concentration, the pH and the temperature. The study of kinetics of retention has shown that the latter is consistent with second-order kinetics. In addition, the higher correlation coefficient values indicate the relevance of the Freundlich model for toluene adsorption, and the Langmuir model for the adsorption of heavy metals and dyes. The study of thermodynamic parameters has confirmed that the process of adsorption favoured at a high temperature, it is spontaneous in most cases. Finally, the regeneration study of diatomite was performed. In conclusion, natural and modified Tunisian diatomite can be used as a good adsorbent in the field of water treatment containing pollutants.