Synthesis of Iron-Doped Titanium Oxide Nanoadsorbent and Its Adsorption Characteristics for Fluoride in Drinking Water

A novel iron-doped titanium oxide adsorbent was synthesized by precipitation from a solution of Ti(SO4)(2) and FeSO4 and used for fluoride removal from drinking water. The effects of the final pH of the precipitation solution on the adsorbent structure were investigated, and optimized conditions for the synthesis were obtained. The iron doped into the titanium oxide increased the amount of active hydroxyl groups on the adsorbent surface, which increased the fluoride adsorption capacity. The optimized adsorbent had an adsorption capacity of 53.22 mg/g, obtained by fitting adsorption data to the Langmuir isotherm. The adsorption of fluoride followed second-order kinetics. The initial pH of the fluoride solution had little effect on the adsorption capacity. A thermodynamics analysis showed that the adsorption of fluoride ions onto the adsorbent was spontaneous. The adsorbent was easily regenerated with an alkali solution.