Immobilized ZnO/TiO2 activated carbon (I ZnO/TiO2 AC) to removal of arsenic from aqueous environments: optimization using response surface methodology and kinetic studies

Removal of arsenic (As), as a toxic, carcinogenic, and mutagenic water pollutant, has been a topic of much thought and discussion within environmental experts newly. One of the most popular AS removal method from aqueous solution is adsorption. To the best of our knowledge, the combination of ZnO/TiO2 immobilized on activated carbon (AC) has not been used to AS removal from water. Therefore the aims of this study are (i) to develop a novel immobilized ZnO/TiO2 activated carbon (I ZnO/TiO2 AC) for effective and economic arsenic removal, (ii) to investigate the effects of different variables (e.g., pH, contact time, dose) on I ZnO/TiO2 AC system efficiency, (iii) to achieve nonlinear modeling using response surface methodology (RSM) approach, and (iv) to optimize I ZnO/TiO2 AC system for As removal from water with RSM-based developed model. The final appropriate solution which was selected by developed response surface model demonstrated that the best dosage, pH, contact time, and initial concentration to reach permitted concentration for output (10 mu g/L) are 5.187 g/L, 6.758, 287.574 min and 9.767 mg/L, respectively. The appropriate achieved desirability (0.996) depicted that the solution is acceptable.