Fabrication of 3D Gelatin Hydrogel Nanocomposite Impregnated Co-Doped SnO Nanomaterial for the Catalytic Reduction of Environmental Pollutants.

In the catalytic reduction of various environment pollutants, cobalt-doped tin oxide, i.e., Co-SnO intercalated gelatin (GL) hydrogel nanocomposite was prepared via direct mixing of Co-SnO doped with GL. Then, it was crosslinked internally using formaldehyde within a viscous solution of gelatin polymer, which led to the formation of GL/Co-SnO hydrogel nanocomposite. GL/Co-SnO hydrogel nanocomposite was fully characterized by using field-emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD), and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). The FESEM images indicate that the Co-SnO composite has a spherical structure on the GL matrix while EDX elucidates the elemental composition of each atom in the crosslinked GL/Co-SnO hydrogel nanocomposite. The GL/Co-SnO nanocomposite was checked for the reduction of various pollutants, including 2-nitro-phenol (2-NP), 2,6-dinitro-phenol (2,6-DNP), 4-nitro-phenol (4-NP), Congo red (CR), and methyl orange (MO) dyes with a strong sodium borohydride (NaBH) reducing agent. The GL/Co-SnO nanocomposite synergistically reduced the MO in the presence of the reducing agent with greater reduction rate of 1.036 min compared to other dyes. The reduction condition was optimized by changing various parameters, such as the catalyst amount, dye concentration, and the NaBH amount. Moreover, the GL/Co-SnO nanocomposite catalyst can be easily recovered, is recyclable, and revealed minimal loss of nanomaterials.