Kinetics, equilibrium, and thermodynamics of ammonium sorption from swine manure by natural chabazite

Sorption kinetics and equilibria were evaluated in shaken-batch mode for ammonium separation from liquid swine manure through chabazite, a type of Ca-dominated natural zeolite. A set of kinetic and isothermal models were assessed. Total ammoniacal nitrogen sorption capacity was 11.6 mg/g-chabazite, and the maximum sorption capacity at room temperature was 34.2 mg/g-chabazite. Thermodynamic parameters indicated the spontaneity and exothermic nature of the sorption. Chabazite sorption decreased soluble phosphorus, possibly by forming insoluble calcium phosphate. This study demonstrated that chabazite sorbent was effective for ammonium separation from liquid swine manure, and the resulting sorbent may be used as slow-release nitrogen fertilizer.