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.