Removal of Ammonia Nitrogen from Aqueous Media with Low-cost Adsorbents: a Review

Ammonia nitrogen pollutant in aqueous media is difficult to treat, which leads to a deterioration of pristine water ecosystems because of eutrophication and poses significant risks to human health. The efficient treatment of low-concentration ammonia nitrogen wastewater remains difficult. Adsorption is a promising remediation strategy, but suitable adsorbent materials that are abundant, low-cost, environmentally friendly, and efficient remain challenging to find. Recent developments in low-cost adsorbent materials for ammonia nitrogen removal from aqueous solution have been summarized. The physicochemical properties; ammonia removal mechanism; and advantages and disadvantages of representative adsorbent materials, including natural mineral materials, industrial byproducts, biochar, biopolymers, and their modified forms, have been compared. Future perspectives and research directions on the use of inexpensive adsorbents for ammonia nitrogen removal have been provided.