Fe―Ti oxide nano-adsorbent synthesized by co-precipitation for fluoride removal from drinking water and its adsorption mechanism

A novel bimetallic oxide adsorbent was synthesized by the co-precipitation of Fe(II) and Ti(IV) sulfate solution using ammonia titration at room temperature. The influences of the washing and drying methods, Fe/Ti molar ratio, and calcination temperature used in the preparation on the morphology, crystallization, surface structure and adsorption capacity were investigated. An optimized Fe―Ti adsorbent had a Langmuir adsorption capacity of 47.0 mg/g, which was much higher than that of either a pure Fe oxide or Ti oxide adsorbent. There was a synergistic interaction between Fe and Ti in which Fe―O―Ti bonds on the adsorbent surface and hydroxyl groups provide the active sites for adsorption, and Fe―O―Ti―F bonds were formed by fluoride adsorption. The novel Fe―Ti adsorbent is efficient and economical for fluoride removal from drinking water.