Document Type : Original Article
Egyptian Petroleum Research Institute
Botany and Microbiology Dept., Faculty of Science Al-Azhar University, Nasr City, Cairo, Egypt.
Visible light-responsive photocatalysis is a green and efficient wastewater treatment technique, and carbon materials-based semiconductors have demonstrated excellent performance in this area. In this work, zinc oxide nanoparticles (ZnO NPs) are synthesized via a simple, economic and green method using Streptomyces microbial extract as non-toxic reducing and capping agent. The prepared ZnO is supported on the exfoliated graphite (ZnO/EG) by a simple mixing method. Various techniques including XRD, FTIR, DLS, Zeta, BET, TEM and optical properties of the prepared photocatalysts were elucidated. The results reveal that the ZnO particles are well dispersed on the EG in the ZnO/EG sample. Also, diffuse reflectance spectroscopy revealed that the ZnO/EG nanocomposite possesses an increased light absorption toward the visible light region, as a result of the presence of the EG. The photocatalytic performance of the prepared photocatalysts was discussed using Malachite Green (MG) dye under both UV and visible light. The effect of dye concentration, photocatalyst dose, pH and different scavengers was studied. The activity of the ZnO/EG (94.06 %, rate, k = 0.0184 min-1) is enhanced under visible light rather than ZnO alone (50.05 %, rate, k = 0.0030 min-1), which will be a promising and competing candidate for wastewater treatment.