Removal of fluoride from aqueous solution by TiO2-based composites

In this work, novel composite materials were synthesized using SiO2 and Fe3O4 to support TiO2 to improve its physicochemical and sportive properties. Surface morphology, specific surface area, chemical structure, and thermal stability of the resulting adsorbents, SiO2-TiO2, Fe3O4-TiO2, and Fe3O4-SiO2-TiO2, were determined. Adsorption of fluoride onto the three TiO2-based composites was evaluated and the results indicated that all the adsorbents effectively removed fluoride from aqueous solution with high adsorption capacities (22.4-152.2 mg/g). SiO2-TiO2 was the best among the three adsorbents, indicating SiO2 was an effective carrier for TiO2. Although the other two adsorbents showed fluoride sorption, the presence of Fe3O4 particles made the composites magnetic. Findings of this work suggested that TiO2-based composites have great potential to be used as high-efficiency adsorbents for the removal of fluoride from water. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.