Impact of Influencing Parameters on the Adsorption of Nickel by Kaolin in an Aqueous Medium

In this study, nickel elimination per kaolin from Guelma/Algeria in aqueous medium was examined by applying several parameters, namely the agitation speed, pH, temperature, particle size of the solid and initial concentration. The physico-chemical investigations accomplished indicated that the kaolin in majority is composed of silica (46.58%) and alumina (36.82). The measured specific surfaces of the raw and activated kaolin samples are respectively 98m2/g and 310m2/g. The pH value corresponding to the PZC is around 3.1. The adsorption capacity is measured after 60 minutes of stirring under specific conditions, namely Vag: 150 rpm; pH: 4.3; T: 20°C; Øs: 200µm corresponds to 45.39 mg/g. The study of the adsorption isotherms demonstrated that the Langmuir model was better adapted to the experimental data than the Freundlich and Temkin models. The values of the Langmuir parameter RL, showed that the nickel adsorption process is favourable. The kinetic study has revealed that kinetics follows the pseudo-first-order model. However, a diffusion study has indicated that the transfer of nickel from the solution to the adsorbent was successfully controlled by external and intra-particle diffusion. The effect of temperature has indicated that this adsorption is physical, spontaneous (ΔG°<0), exothermic (ΔH°<0) and less entropic (ΔS°<0). The nickel desorption from charged kaolin is more efficient using hydrochloric acid at 0.1N as eluent. Considering of the determined results, we estimate that kaolin from Guelma / Algeria, can be valued as a reliable, efficient and economical adsorbent for the elimination of nickel from wastewater.