Study of the adsorption of nickel ions on the sea shells of Mehdia: Kinetic and thermodynamic study and mathematical modelling of experimental data

Abstract

In order to optimize and reduce the rate of inorganic micropollutants discharged by various metal facilities, according to wastewater treatment standards and environmental protection, we have proceeded by studying the adsorption of heavy metals such as nickel using sea shells-Mehdia-Morocco as a natural adsorbent.After the preparation of the support, we are interested in the analysis of the physico-chemical parameters influencing the removal of heavy metals such as the kinetics (6.5 to 50 mg.L-1), the initial concentration of the nickel solutions (10 mg.L-1) and the pH of the solution (5.5 to 9.5).All the results obtained show that the adsorption process is favourable to physisorption and monolayer. First, the adsorption amount was found to be 4.05 mg.g−1. Among others, the adsorption process is expressed by the second order kinetic law (R2 = 0.999, 1 / n = 0.37). Moreover, the thermodynamic parameters after using Van't Hoff's equation showed that the studied process has an endothermic, stable and spontaneous effect (ΔG ° = −0.37 Kj.mol−1, ΔH° = 47.31 Kj.mol−1 et ΔS° = 150.56 J.mol−1). Finally, the linear isothermal models of Langmuir (R2 = 0.925), Freundlich (R2 > 0.96) and Temkin (R2 = 0.891), show that the binding and elimination of nickel by this shell is rapid with the increase of the above-mentioned parameters.