Apatite-type calcium phosphates modified by Ti 4+ and CO 3 2- ions and their composites with TiO 2 : synthesis, optical properties and photocatalytic activity

To address the challenging removal of pharmaceutical pollutants from aqueous environment, this study presents the synthesis of apatite-related Ti4+ and CO32--modified calcium phosphates and their TiO2 composites using various Ti4+ precursors. The partial substitution of Ca2+ by Ti4+ ions is confirmed by decreased lattice parameters. Tetraisopropylorthotitanate promotes Ti4+ intercalation, reducing the bandgap energy. The composites demonstrated efficiency in the tetracycline hydrochloride degradation (up to 88%) due to synergistic effects of enhanced adsorption and efficient charge carrier interaction. These findings highlight the potential of the developed materials for the pharmaceutical pollutants’ removal from aqueous environments.