Photocatalytic behavior for removal of methylene blue from aqueous solutions via nanocomposites based on GdO/CdS and cellulose acetate nanofibers.

Efficient cleaning of contaminated water by photocatalysis has become an effective strategy in recent years due to its environmental and ecological designation. Cadmium sulfate (CdS) is an excellent photocatalyst in the visible region but has low quantum efficiency. In order to increase the photocatalytic efficiency, CdS was modified with gadolinium oxide (GdO) and combined with graphene oxide (GO) nanoparticles. The estimated crystallite size (D) for GdO, CdS/GdO, and CdS/GdO@GO was 29.6, 11.6, and 11.5 nm, respectively. The degradation of methylene blue (MB) reaches the highest values after 60 min under visible light irradiation with a dye concentration of (0.25 ppm). Whereas in powdered composition the efficiency of dye removal has been enhanced under UV irradiation, it reduced by increasing the MB concentration to 0.50 ppm with visible light irradiation. In addition, the CdS with/without GdO and GO were integrated into electrospun nanofibrous cellulose acetate (CA) through the electrospinning technique. The compounds of GdO, CdS/GdO, and CdS/GdO/GO were encapsulated into CA nanofibers for the degradation of MB under visible and UV irradiation. The apparent rate constant (k) achieves a value of 0.006, 0.007, and 0.0013 min while the removal efficiency reaches 41.02%, 54.71%, and 71.42% for GdO@CA, CdS/GdO@CA, and CdS/GdO/GO@CA, respectively, after 60 min under UV irradiation.