Photocatalytic wastewater purification under visible light irradiation using bismuth molybdate hollow microspheres with high surface area

Abstract

Recently, global-scale efforts have been devoted to development of eco-friendly and green technologies to remediate pollution of water resources. In line with global efforts, this study prepared visible light active bismuth molybdate hollow microspheres (Bi2MoO6 HMSs) using carbon microspheres, as the synthesis template. The utilized carbon microspheres were synthesized from fructose through a simple one-step hydrothermal process. The structural and spectrophotometric results indicated that the prepared HMSs have an orthorhombic crystal structure with the Brunauer–Emmett–Teller (BET) surface area of 117.8 m2 g−1 and the band gap energy of 2.45 eV. The Bi2MoO6 HMSs were then applied to lab-scale photodegradation of two anionic and cationic dyes under visible light. The photocatalytic studies declared that the HMSs are highly efficient in photodegradation of the methyl orange (MO; cationic) and methylene blue (MB; anionic) dyes under ultraviolet and visible light irradiations in aqueous solutions. The photocatalytic performance of the HMSs was also compared with the activity of the P25 photocatalyst. The results demonstrated that the Bi2MoO6 HMSs are five times more active than the P25 particles under visible light. Finally, with respect to the impact of various scavengers, •O2−, h+ and •OH were found to play key roles in the photodegradation process.