Abstract

Aims: The aim of this study was to evaluate the photocatalytic processes for cadmium (Cd2+) and lead (Pb2+) removal at continuous and batch system. Materials and Methods: This study was performed at laboratory scale. The reactors used in this study consisted of three parts: Ultraviolet (UV) source, reaction cell, and mixing chamber. The experiments were carried out in a batch and continuous reactor for synthetic wastewater. The concentration of Cd2+ and Pb2+ was constant (25 mg/L) in all experiments and effect of titanium dioxide (TiO2) dose, pH, and air dispersion was investigated on the removal efficiency. Results: The results showed that with increasing TiO2 dose and pH, the cadmium and lead removal increase. The maximum removal of cadmium and lead was obtained in TiO2 dose 0.9 g/L and pH: 11 that were equal to 99.8 and 99.2 respectively. Furthermore, when air dispersion increased, the removal efficiency increased; while in the air dispersion 2 cm3/L the removal efficiency was maximum (88 and 93.2 at the contact time 56 min for Cd2+ and Pb2+, respectively). Conclusion: According to these results the TiO2 has been considered as photocatalyst is the separable and recyclable, so UV/TiO2 process is an environment friendly process for toxic metal removal. © 2014 Rahimi S. This is an open‑access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.