Simultaneous recovery of ammonium and phosphate from aqueous solutions using Mg/Fe modified NaY zeolite: Integration between adsorption and struvite precipitation

Currently, the closure of the nutrient circular loop and contaminant removal from wastewater are drawing widespread attention. In this study, a novel MgO/iron oxide-modified NaY zeolite (MNZ) was prepared and used for the integration of adsorption and struvite precipitation to simultaneously reclaim ammonium and phosphate from wastewater. The results proved that MgO and iron oxide nanoparticles were successfully embedded in the zeolite matrix, providing high adsorption performance for ammonium and phosphate, reaching 380.02 (as NH + 4) and 324.68 (as P-T) mg/g, respectively. The presence of NO3-, Cl-, SO42-, and HCO3- did not significantly influence the adsorption of ammonium and phosphate. Struvite precipitation on the MNZ surface is the primary mechanism for the recovery of both ammonium and phosphate with electrostatic attraction and ion exchange also involved in ammonium uptake. These results indicate that optimized MNZ is promising for nutrient recovery from wastewater because of its high selectivity for targeted absorbates and its potential application as a slow-release eco-fertilizer.