Enhanced Photocatalytic Efficiency of Soft Chemically Synthesized MAl2O4 / Activated Carbon Based Composite in the Removal of Toxic Malachite Green Dye Under Visible Light

Abstract Composites of spinel aluminate (MAl2O4) based materials having activated carbon (AC) as the base materials were synthesized using chemical precipitation method. The as synthesized photocatalyst was characterized using X-Ray Diffractometry (XRD), Fourier transform Infrared Spectrophotomatry (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDS) and UV- DRS studies. The XRD confirms the presence of amorphous phase along-with crystalline spinel phase. The bonds related to tetrahedral and octahedral sites of the spinel were confirmed by FTIR. EDS confirmed the presence of appropriate elements. The presence of pores in the sample was shown by SEM. The UV-Visible spectra of the spinel – AC composites exhibited λmax in the range of 365–400 nm. The composites were very effective in the photo-degradation of MG dye from water. The photocatalytic degradation of MG follows pseudo first order reaction mechanism i.e., Langmuire and Hinshelwood kinetic model. Among the photocatalysts studied, Co0.85Ni0.15Al2O4−δ /AC exhibited excellent degradation efficiency in removing MG completely within 90 minutes under visible light irradiation.