Removal of acetylsalicylate and methyl-theobromine from aqueous environment using nano-photocatalyst WO3-TiO2 @g-C3N4 composite

Highly efficient, visible light-driven and a novel ternary hybrid photocatalyst WO3-TiO2-g-C3N4 with robust stabilities and versatile properties has been synthesized through facile hydrothermal method. This study considers the photo-degradation of aspirin (acetylsalicylate) and caffeine (methyl-theobromine) via photocatalysts (WO3, WO3/TiO2, and WO3/TiO2/g-C3N4 (WTCN) composite) under visible-light irradiation. The SEM and TEM images show the formation of WO3 nanoparticles with orthorhombic structure and average particle size of 65 nm. The photocatalyst WTCN composite possesses higher-catalytic activity when compared to that of WO3 and WO3/TiO2 for degradation of aspirin and caffeine. The incorporation of g-C3N4 in WO3/TiO2 composite exhibited significant influence on the photocatalytic performance for both pollutants. Excellent photocatalytic performance of WTCN composite was observed owing to hydroxyl radical (OH) and superoxide radical (02) as main active species. The enhanced photocatalytic activity of WTCN composite can be attributed to following three reasons: (1) extended visible-light absorption; (2) extended surface area; (3) efficient charge-separation due to synergistic effects between g-and WO3/TiO2 composite. The removal efficiency of aspirin and caffeine (Methyl theobromine) could be achieved as much as 98% and 97% for acetylsalicylate and methyl-theobromine using WTCN composite material, respectively. This study could provide new insights into the synthesis of novel WO3-based materials for environmental and energy applications.