Application of Nanoporous Zeolites for the Removal of Ammonium from Wastewaters: A Review

Abstract

This contribution deals with low-cost nanoporous zeolite for the removal of ammonium from wastewaters. Adsorption processes are widely used to remove certain classes of pollutants from wastewaters, especially those that are not easily biodegradable. Natural and synthetic zeolites are widely used as adsorbents for gas or liquid purification. Natural zeolite is abundant in the world and is usually regarded as low-cost material. In this review, an extensive list of nanoporous zeolites used for ammonium removal in the literature has been compiled. The review evaluates (i) ammonium adsorption capacities and other parameters in batch systems; (ii) ammonium removal efficiency from wastewaters in fixed-bed systems; and (iii) a combination of biological treatment and adsorption on zeolite for the removal of ammonium from wastewaters. It is important to note that the adsorption capacities of the zeolites presented in this paper vary depending on the characteristics of zeolite, the extent of chemical modifications and the concentration of adsorbate.