Study of nickel adsorption on NaCl-modified natural zeolite using response surface methodology and kinetics modeling

In this study, a natural Algerian zeolite of the mordenite type was activated and tested for nickel adsorption in aqueous solution. Na-mordenite was characterized by different techniques, such as X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Brunauer-Emmett-Teller (BET) analysis shows that this mineral was a micro-meso-macroporous material with a high specific surface area (S-BET = 124.95 m(2)/g) and a total pore volume of 0.45 cm(3)/g. Box-Behnken Design (BBD) was used to optimize the adsorption process. The optimal conditions predicted by the model were: initial concentration -10 mg/L; adsorbent content -0.32 g/L; and pH of nickel solution -5.27. Under these conditions, the experimental value of nickel removal (R = 95.13%) was in good agreement with the predicted value (R = 96.71%). Kinetic and isotherm studies revealed that the Avrami kinetic model and Redlich-Peterson isotherm best expressed the experimental data. Based on the X-Ray Fluorescence results and zeta potential measurements, the mechanism of nickel adsorption by Na-mordenite appears to be an electrostatic and ion-exchange process.

Automated summary

In this study, an Algerian zeolite was activated and tested for its nickel adsorption ability in aqueous solution. The results showed that the Na-mordenite had a high specific surface area and a total pore volume. The optimal conditions for nickel adsorption were determined using a Box-Behnken Design and the experimental data agreed well with the predicted values. Kinetic and isotherm studies revealed that the Avrami kinetic model and Redlich-Peterson isotherm best described the experimental data. The mechanism of nickel adsorption by Na-mordenite was found to involve electrostatic and ion-exchange processes.