Patent ID: 7786038

Claim:
A composite metal oxide adsorbent for fluoride removal consisting of a transition metal, Al and/or Mg, and a rare earth metal, wherein the molar ratio of the transition metal, Al and/or Mg, and the rare earth metal is 0.05-0.15:0.2-0.6:0.05-0.15, wherein the transition metal is one or more selected from the group consisting of Ti, Mn, and Fe, and wherein the rare earth metal is Ce and/or La, said composite metal oxide adsorbent is prepared by a process comprising the steps of: (a) preparing an aqueous solution comprising a transition metal containing compound, Al and/or Mg containing compound, and a rare earth metal containing compound, wherein the transition metal, Al and/or Mg, and the rare earth metal have a molar ratio of 0.05-0.15:0.2-0.6:0.05-0.15; (b) adjusting the pH of the aqueous solution to be 8.0 or more to form a precipitate; (c) washing the precipitate with deionized water until the pH of the water flowing out is neutral to obtain a washed product; (d) drying the washed product at 65-120° C. to a constant weight; and (e) baking the washed product at a temperature between 250 to 500° C. to obtain a baked product (f) remilling the baked product to produce the composite metal oxide adsorbent; and wherein said composite metal oxide adsorbent has a diameter of between 150 and 200 meshes and a saturation adsorption capacity for fluoride of 100 mg/g or more under a neutral condition.