Use of Response Surface Methodology for Optimization of Nickel Adsorption in an Aqueous Solution by Clay

Abstract

In this study, Scanning Electron Microscopy (SEM), X-ray diffraction and BET surface area (SBET) methods were employed to characterize the adsorbent. Response Surface Methodology (RSM) was consider as a good method to assess Ni adsorption treatment and Box-Behnken design was used to examine simultaneous the effects of different experimental variables (pH, adsorbent dosage, contact time). Experimental results showed high adsorption efficiency. Statistical analysis showed a high correlation coefficient (R² value 0.9578). It was showed that adsorption efficiency raised as contact time and adsorbent dosage raised. The best results were acquired with optimum conditions. A contact time of 120 min and an adsorbent dose of 0.5 mg L^-1 give the highest adsorption capacity. The similarity between observed and predicted values sustains the relevance of the model to estimate the adsorption process. It was suggested that Langmuir and Freundlich isotherm models fitted for Nickel adsorption process (R² values ranged between 0.92 and 0.99). The results showed that adsorption efficiency increased as temperature increase. Mostly, Tunisian clay may be assessed as powerful adsorbent for the adsorption of Nickel from aqueous solution.