Adsorption of high ammonium nitrogen from wastewater using a novel ceramic adsorbent and the evaluation of the ammonium-adsorbed-ceramic as fertilizer

► Kanuma clay and Akadama clay are typical cultivating clay in Japan. ► Kanuma clay and Akadama clay were firstly used to synthesize the ceramic adsorbent. ► High NH4+-N of wastewater was removed using the ceramic adsorbent. ► The maximum NH4+-N adsorption capacity achieved 75.5 mg g−1. ► The NH4+-N-adsorbed ceramic adsorbent could be utilized as fertilizer.