Visible light assisted photodecolorization of eosin-Y in aqueous solution using hesperidin modified TiO2 nanoparticles

Hesperidin a flavanoid, modified TiO2 nanoparticles (Hes-TiO2) was synthesized to improve the visible light driven photocatalytic performance of TiO2. The synthesized nanoparticles were characterized by UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), FT-IR, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activity of Hes-TiO2 was investigated based on the decolorization of eosin-Y under visible light irradiation. Hes-TiO2 showed high efficiency for the decolorization of eosin-Y. The influences of various reaction parameters like effect of pH, catalyst dosage and initial dye concentration on the photocatalytic efficiency were investigated. The adsorption of eosin-Y on Hes-TiO2 was found favorable by the Langmuir approach. The removal percentage of chemical oxygen demand (COD) was determined to evaluate the mineralization of eosin-Y during photodecolorization. Based on the intermediates obtained in the GC-MS spectroscopic technique, a probable degradation mechanism has been proposed.

(a) UV-vis absorption changes of eosin-Y in the presence of Hes-TiO2, (b) photodecolorization curves of eosin-Y in the presence of Hes-TiO2 and TiO2.Highlights► The complete mineralization of organic pollutants into CO2 and H2O can be brought about by TiO2 semiconductor photocatalysis. ► Hesperidin modified TiO2 nanoparticles greatly improve the photodecolorization of eosin-Y. ► Hesperidin modification sharpens the band gap of TiO2. ► COD experiments confirm the mineralization of eosin-Y during photocatalysis. ► A possible reaction mechanism for the decolorization of eosin-Y was proposed by GC-MS analysis.