Sol-gel assisted Ag doped NiAl2O4 nanomaterials and their nanocomposites with g-C3N4 nanosheets for the removal of organic effluents

Abstract

Sol–gel approach was employed for synthesis of nickel aluminate (NiAl2O4, NA), and silver doped nickel aluminate (Ag-NiAl2O4, AgNA) nanomaterials. The ultra-sonication approach was employed to synthesize their composite with graphitic carbon nitride (Ag-NiAl2O4@g-C3N4, AgNA@gCN) for degradation of organic effluents such as methylene blue (MB), crystal violet (CV), and benzoic acid (BA) photocatalytically. The synthesized photocatalysts were characterized by various techniques like X-rays diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and UV–visible spectroscopy. XRD confirmed the formation of doped and un-doped NiAl2O4. The crystallite size of as-prepared nanomaterials was found out less than 13 nm. FT-IR technique was used for functional groups detection present in synthesized photocatalysts. The surface morphology of fabricated nanomaterials was investigated via SEM. The thermal stability of prepared samples was investigated via TGA. Optical analysis was carried out by UV-Visible spectrophotometer. NA and AgNA exhibited the bandgap energy of 3.50 eV, and 2.88 eV respectively. The photocatalytic efficiency of fabricated samples was analyzed under solar light. AgNA@gCN exhibited 85.26% degradation of MB, 83.87% of CV, and 68.46% of BA under sunlight. The overall removal (%adsorption + % degradation) of MB, CV, and BA by AgNA@gCN were 99.67%, 98.54%, and 76.91% respectively. The scavenging experiment was also performed to find out the most photoactive species involve in the degradation of organic effluent photocatalytically. Hydroxyl radicals are the mainly photoactive species responsible for the photocatalytic experiment.