No abstract

Zirconium(IV) loaded Diaion CRP 200 methylenephosphonate resin was tested in the column mode removal of fluoride by repeating the adsorption-elution-regeneration procedure for a long term. This ligand exchanger was highly selective to fluoride; no interference of chloride, nitrate, and sulfate was observed. On the contrary, their sodium salts enhanced the breakthrough capacity of fluoride. In addition, it was clarified that the reloading of small amount of Zr(IV) in each regeneration step overcompensate the loss of Zr(IV) from the column in the preceding elution process, accompanying with the marked increase in the breakthrough capacity of fluoride.