Removal of dyes by photocatalytically active curcumin-sensitized amorphous TiO₂ under visible light irradiation

Curcumin-sensitized amorphous TiO₂ (Cur-AMO) was prepared by the sol–gel process followed by modified impregnation using freshly prepared curcumin solution. The final products were studied by several techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, surface area measurement (BET), and UV–Vis diffused reflectance spectroscopy. Experimental results revealed that the presence of curcumin did not affect the amorphous form; however, it caused bathochromic shift and decreased the BET surface area. The products showed not only high adsorption efficiency but also increased photocatalytic activity under visible light irradiation with optimal result at 7.5 wt% curcumin loading. Under visible light irradiation, curcumin molecule could act like dye-sensitizing agent by injecting the electron into the conduction band of amorphous TiO₂, leading to photodegradation of pollutant in wastewater.