Development of novel polysulfone membranes with embedded zirconium sulfate-surfactant micelle mesostructure for phosphate recovery from water through membrane filtration

We prepared novel membranes that could adsorb phosphate from water through membrane filtration for use in a phosphate recovery system. Zirconium sulfate surfactant micelle mesostructure (ZS), which was the phosphate adsorbent, was embedded in a polysulfone matrix and flat sheet ultrafiltration membranes were made by nonsolvent induced phase separation. Scanning electron microscopy showed that the ZS particles existed on both the top surface and in the internal surface of the membrane. Increases in ZS content led to greater pure water flux because of increases in the surface porosity ratio. The amount of phosphate adsorbed on the membrane made from the polymer solution containing 10.5 wt% ZS was 0.071 mg P/cm2 (64.8 mg P/g-ZS) during filtration of 50 mg P/L synthetic phosphate solution. The membrane could be repeatedly used for phosphate recovery after regeneration by filtration of 0.1 M NaOH solution to desorb the phosphate. We applied the membrane to treat the effluent from an anaerobic membrane bioreactor as a real sample and successfully recovered phosphate.