Sand Supported Mixed‐Phase TiO₂ Photocatalysts for Water Decontamination Applications

Using an organometallic precursor, TiO₂ coatings were fabricated on surfaces of quartz, zircon, and rutile sands. X‐ray diffraction, X‐ray fluorescence, UV–vis spectroscopy, and surface area measurement were used to characterize support materials. The phase composition and morphology of the coatings were characterized by laser Raman microspectroscopy and scanning electron microscopy, respectively. A packed bed reactor was used to study the inactivation of Escherichia coli in recirculating water by the supported photocatalysts. It was found that the sand grains were well coated with a homogenous layer of TiO₂ and coatings were well adhered, exhibiting a mixed anatase‐rutile composition after firing at 850 °C. Photocatalytic activity was highest in coatings applied to quartz sand, although sterilization of the recirculating water was not achieved with any of the materials investigated. The advantages of quartz as a TiO₂ photocatalyst support material are likely a result of this material's higher purity and optical transmittance. Potential enhancement through Si doping cannot be ruled out.