Valorization of Waste Tungsten Filament into mpg-C 3 N 4 -WO 3 Photocatalyst: A Sustainable e-Waste Management and Wastewater Treatment.

The waste of tungsten filament materials in the environment is one of the reasons for environmental pollution, and it is very dangerous to animals and plants. To date, not much attention has been given to its utility or recyclability. Herein, the present work reported the synthesis of tungsten trioxide nanoparticles (WO 3 NPs) by the utilization of cost-free waste tungsten filament by a simple calcination method. A mesoporous graphitic carbon nitride-tungsten trioxide (mpg-C 3 N 4 -WO 3 ) composite designed from the WO 3 NPs produced from tungsten filament waste and thiourea as a carbon and nitrogen precursor by a one-step calcination method. The synthesized samples were characterized and confirmed by different characterization techniques. The photocatalytic behavior of the synthesized mpg-C 3 N 4 -WO 3 composite was assessed, with respect to the effect of initial pH, amount of photocatalyst, dye concentration, and reaction time, as well for the degradation of Methylene Blue (MB) dye under sunlight. The best photocatalytic performance (92%) was achieved using mpg-C 3 N 4 -WO 3 with experimental condition ([photocatalyst] = 100 mg/L, [MB] 0 = 10 mg/L, pH 8, and time = 120 min) under sunlight irradiation with excellent photostability than that of isolated mpg-C 3 N 4 and WO 3 NPs. The histotoxicological studies also showed that the photodegraded products of MB were found to be nontoxic and did not structurally changes in the gill architecture as well as brain tissues of freshwater fish Labeo rohita .