Preparation of wheat bran-titanium dioxide (TiO2) composite and its application for selenium adsorption

Abstract Selenium is metabolically required by a variety of organisms, but it may induce toxicity at high doses. The removal of a high concentration of selenium from water with natural and biocompatible materials is a vital component in the reuse of selenium given that the process converts low-cost materials into value-added products. In this study, novel wheat bran-titanium dioxide (TiO2) composite was prepared through the in situ hydrolysis of titanium oxysulfate in the presence of wheat bran after destarching, and its sorption characteristics toward Se(IV) from aqueous solutions were investigated. Scanning electronic microscopy and X-ray diffraction results revealed that amorphous TiO2 particles dispersed in the fiber matrix and on the fiber surface. The sorption of Se(IV) on the wheat bran-TiO2 composite was fast and pH dependent. The wheat bran-TiO2 composite exhibited high sorption capacity for Se(IV) at high temperatures, and the Langmuir isotherm models were able to fit the experimental data. The presence of phosphate reduced the efficiency of Se(IV) adsorption, whereas other coexisting anions had no significant effect on Se(IV) adsorption. Fourier transform infrared analysis showed that the hydroxyl groups of TiO2 on the composite surface were involved in Se(IV) adsorption. The hybrid wheat bran-TiO2 composite has a promising application for Se(IV) sorption and enrichment in aqueous solutions.