Preconcentration method for phosphate in water using activated carbon loaded with zirconium

Abstract

An effective and simple method for preconcentration of phosphate in aqueous solution has been developed, using activated carbon loaded with zirconium (Zr-C*). The Zr-C* was prepared by mixing 100 ml of zirconyl nitrate solution (1 g Zr, pH 1.6) with 10 g of activated carbon at 25 ° C for three days, filtering and drying the residue in air. 10 g of the resulting material included 0.5 g to 0.6 g of zirconium. The adsorption of phosphate and its desorption depend only on the pH of solution. They occur quantitatively and instantaneously at pH below 8.0 and above 13.5, respectively. An aqueous solution with the pH adjusted to 1.5 is passed through the Zr-C* bed formed on a membrane filter paper with the aid of suction. The collected phosphate is then recovered by eluting with 40 ml of 1 M sodium hydroxide solution. Pyrophosphate, tripolyphosphate and metaphosphate behave as similar as orthophosphate.