Background: Ammonium has introduced to environment by various resources such as industrial, domestic and agricultural effluents. Ammonium is toxic which can lead to oxygen depletion in the water and threating aquatic. On the current method for ammonium removal from water and wastewater is ion exchange and adsorption of the ion by zeolite. The objective of this study was removing of ammonium by Kaolin, zeolite synthesized from Kaolin and magnetic zeolite from aqueous solutions.

Methods: In this study, various concentrations of Kaolin and synthesized zeolite (0.5, 1, 1.5, 2, 2.5 g/l) within aqueous solution containing ammonium ions (1- 20 mg/l) with different contact time (10-240 min) and pH values (3, 5, 7, 9, and 11) were probed. Using SEM, XRD and FTIR analysis, chemical characterization of synthesis Zeolite were studied. 

Results: The maximum ammonium adsorption occurred at pH=7 and in 240 minutes contact time. By increasing initial concentration of ammonium, its sorption capacity was increased. However, by increasing the adsorbent dose, the removal efficiency was decreased. Optimum dosage of kaolin and zeolite was 2 g/L and 1.5 g/L, respectively. The isotherm data of ammonium were correlated reasonably well by Freundlich isotherm model. It was found that the adsorption of ammonium ion on kaolin, synthesis zeolite and magnetic zeolite followed pseudo-second order kinetic model.