Removal of nickel from aqueous solutions using natural clay from northern morocco

In the present study, natural Moroccan clay from the northern region was used to remove Ni(II) metal ions from model aqueous solutions. Batch adsorption studies were performed with various initial Ni(II) concentrations (from 40 to 200) mg/L, adsorbent dosages from 0,5 g to 7 g, pH, temperature and contact time. The adsorption capacity of Ni(II) increased with the initial concentration of metal ions, the contact time and the pH of the solution, but decreased with an increase in the amount of adsorbent. Overall, adsorption kinetics studies have shown that the nickel adsorption process follows pseudo-second order kinetics with a higher regression coefficient (R-2 = 0,99). The equilibrium adsorption results are better adjusted with the Freundlich isotherm compared to the Langmuir models. The value of the separation factor, (R-L = 0, 06) from the Langmuir equation and the Freundlich constant, (n = 3,3) both give an indi-cation of favorable adsorption. Finally, from thermodynamic studies, the adsorption process was endothermic in nature due to the positive enthalpy (Delta H degrees= 107, 38kjmol(-1)) accompanied by a decrease in Gibbs free energy (Delta G degrees). In summary, Natural clay removed nickel with a maximum adsorption capac-ity of (1,407 mg/g, 300 K, pH = 4). (C) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Fourth edition of the International Conference on Materials & Environmental Science.

Automated summary

In this study, natural Moroccan clay was used to effectively remove Ni(II) metal ions from model aqueous solutions. The adsorption capacity of nickel was influenced by the initial concentration of metal ions, contact time, and pH of the solution, while increasing the amount of adsorbent led to a decrease in adsorption. Kinetics studies showed that the adsorption process followed pseudo-second order kinetics, and equilibrium adsorption results were better described by the Freundlich isotherm. Thermodynamic studies indicated an endothermic nature of the adsorption process.