Immobilization of ammonium and phosphate in aqueous solution by zeolites synthesized from fly ashes with different compositions

Immobilization of ammonium and phosphate by zeolites synthesized from low-calcium (LC-Z) and high-calcium (HC-Z) fly ashes is studied. LC-Z has higher ammonium immobilization capacity while HC-Z has better performance in phosphate uptake. As part of Ca2+ released from HC-Z compete with ammonium the exchangeable sites in LC-Z, LC-Z can affect phosphate immobilization of HC-Z, and HC-Z also lowers ammonium uptake of LC-Z. Separate dosing of LC-Z and HC-Z, i.e., first LC-Z and then HC-Z, is proved better than mixed dosing at simultaneous immobilization of ammonium and phosphate. The effect parameters for phosphate and ammonium immobilization of LTH-Z are investigated.