High efficiency removal of phosphate from water by zirconium sulfate-surfactant micelle mesostructure immobilized on...

A zirconium sulfate-surfactant micelle mesostructure (ZS) was synthesized to investigate its capacity for phosphate removal from water. Its phosphate adsorption kinetics, the effect of pH and interfering anions, adsorption isotherm, desorption capacity, and reusability were investigated. The adsorption isotherms could be described by the Langmuir model. The ZS was an effective adsorbent for phosphate with a very high adsorption capacity (114 mg P/g ZS). The phosphate adsorption capacity increased with decrease in pH. Although the adsorption of nitrate, chloride and acetate ions was negligible, bicarbonate ions were found to be possible interfering anions. The adsorbed phosphate was desorbed effectively using NaOH solution. Since breakage of ZS particles resulted when using NaOH, ZS was immobilized on a polymer matrix and a 50-cycle adsorption-desorption test was carried out to determine the ZS-immobilized polymer (P-ZS) reusability. The P-ZS retained its functionality and adsorption and desorption capacity over 50 cycles without loss of original capacity. A phosphate solution containing about 10 mg P/L was treated in a column packed with P-ZS. The phosphate could be adsorbed completely onto P-ZS up to 1020 bed volumes. These results indicate clearly that ZS is a highly effective adsorbent for phosphate and enables the removal of phosphate from water.