Tuning anatase to rutile ratio in nanocrystalline titania enriched from sustainable beach sand from Cox's Bazar, Bangladesh

A sustainable source of titania (TiO2) is important in applications of photovoltaic devices, photocatalysts, sensors, and so forth. Beach sand from Cox's Bazar, Bangladesh, can be an excellent sustainable source of this titania as almost a quarter of it contains titania in the form of rutile and ilmenite. This study demonstrates the success of a sulfuric acid-based hydrometallurgical process in enriching titania in Cox's Bazar beach sand. The route produces precursors that can be conveniently calcined into nanocrystalline phase-pure anatase or anatase/rutile composites. We used both bulk and surface characterization to determine phase purity, crystallite size as well as surface chemistry, and morphology of the resulting anatase and rutile/anatase mixture. The proportion of anatase/rutile can be tuned by varying digestion times. This hydrometallurgical route can potentially lead to the scalable production of precursors used in producing high-performance nanocrystalline titania from a sustainable source of beach sand from Cox's Bazar of Bangladesh.