Photocatalytic Removal of Cr(VI) in Water by Collagen-based Biochar/g-C3N4/WO3 Composite

The g-C3N4/C/WO3 photocatalyst was prepared by mixing the graphitic carbon nitride (g-C3N4) and C/WO3 that was pyrolyzed by using the tungsten ions tanned discarded collagen fiber in tanning filed following mineral tanning mechanism. Furthermore, the morphology, structure, and properties of g-C3N4/C/WO3 photocatalyst were characterized by scanning electron microscopy, X-ray diffraction, fluorescence spectroscopy and so on. The results showed that the specific surface area of g-C3N4/C/WO3 reached 244.62 m2/g, which was much higher than that of pure g-C3N4 (9.95 m2/g), meanwhile the photocatalytic performance of g-C3N4/C/WO3 was significantly improved. The experiments of Cr(VI) removal showed that the removal rate of Cr(VI) by g-C3N4/C/WO3 was as high as 99.99% under the condition that the amount of catalyst was 0.1 g, the pH of the solution was 2, and the initial concentration of Cr(VI) was 50 mg/L, which was almost not affected by the coexisting substances in water. Additionally，the cycling performance of g-C3N4/C/WO3 was relatively stable after three cycles.