Adsorption of industrial dye by natural Moroccan zeolite: a promising approach for wastewater treatment

The aim of this work is to study the performance of natural Moroccan zeolite for effluent dye removal. The obtained results indicate that the adsorption process efficiency increases when increasing the adsorbent weight and reaction time, versus increasing the adsorbent particle size and temperature, which results in a significant decrease in adsorption efficiency. The experimental kinetic data fit well the pseudo-second-order model. The experimental isotherm data were analyzed using linear isotherm models with two parameters (Langmuir, Freundlish, Temkin, and Dubinin–Radushkevich) and nonlinear isotherm models with three parameters (Redlish–Peterson, Sips, and Toth). The nonlinear transform models provided the highest R² correlation coefficient. The q_m = 298.15 mg g^-1 value indicates a high adsorption capacity and that natural Moroccan zeolite (NMZ) is a good adsorbent to remove coloring effluents. A thermodynamic study was realized, calculating the thermodynamic parameters ΔG, ΔS, and ΔH. Desorption was studied for nine chemical solutions, while reusability was determined with 14 cycles of adsorption. The results of this study will be useful for future applications of this material as an abundant and low-cost adsorbent for removal of anionic dyes.