Hydrothermal synthesis of TiO₂-yeast hybrid microspheres with controllable structures and their application for the photocatalytic reduction of Cr (VI)

Nanoparticle TiO₂ and biological yeast cells have been investigated in previous work. However, the formation of TiO₂-yeast hybrid materials with controllable structures is rarely reported. In the present study, the hydrolysis of titanium tetrabutoxide (TBOB) on the surface of yeast cells was proposed to prepare controllable structures of TiO₂-yeast hybrid microspheres. It also develops and widens the applications of TiO₂-yeast hybrid microspheres for removal of Cr(VI). RESULTS: FE-SEM and EDS revealed that the TiO₂-yeast hybrid microspheres have rough surface morphology and uniform diameter. The XRD pattern indicated anatase phase TiO₂ nanoparticles with amorphous yeast. FT-IR spectroscopy demonstrated that the formation of controllable TiO₂-yeast composite microspheres was related to surface chemical functional groups of yeast. The composite microspheres possessed enhanced light response over the wide range 250-435 nm. The photocatalytic performance of TiO₂-yeast (1.3 mL TBOB) composite microspheres exhibited a maximum removal rate of 99% for the reduction of Cr(VI) under UV light irradiation. CONCLUSIONS: TiO₂-yeast hybrid microspheres with controllable structures were successfully synthesized via a hydrothermal method. The diameter of TiO₂-yeast microspheres decreased with increase of the amount of TBOB. No significant decrease in photo-activity was found when used for the reduction of Cr(VI) and the composites could be re-used repeatedly without other treatment.