Phosphate removal from urine using hybrid anion exchange resin

• Rapid phosphate removal from urine in 5 min or less.
• High phosphate removal from urine up to 97%.
• Pseudo-second-order kinetic model and Freundlich isotherm model describe phosphate sorption.
• High sulfate and chloride did not affect phosphate removal.
• Co-removal of diclofenac and phosphate occurred.

Urine source separation has been proposed as a more sustainable approach to wastewater management than treating combined wastewater streams. One such benefit of urine source separation is nutrient recovery, which has primarily focused on struvite precipitation for recovery of phosphorus. There is no previous research investigating phosphorus recovery from human urine by ion-exchange. Accordingly, the goal of this research was to provide an improved understanding of phosphate removal by ion-exchange using a hybrid anion exchange (HAIX) resin. The specific objectives of this research were to evaluate phosphate removal using HAIX resin in fresh urine and hydrolyzed urine in terms of (1) kinetic tests, (2) equilibrium tests, (3) sorption models, (4) competition among sulfate, chloride, and phosphate, and (5) pharmaceutical co-removal. Batch experiments were conducted using different compositions of synthetic urine. HAIX resin consisted of a strong-base anion exchange resin impregnated with hydrated ferric oxide nanoparticles. The major results of phosphate removal from urine using HAIX resin were rapid removal in 5 min or less, high removal up to 97%, similar ion-exchange behavior in fresh urine and hydrolyzed urine, no affect by sulfate on phosphate removal, and co-removal of pharmaceutical and phosphate.

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