Green synthesis of fly ash‐based zeolite Y by mixed alkali fusion method

A solvent‐free process was used to synthesize high‐purity zeolite Y from fly ash. Different from the traditional two‐step method, fly ash was activated efficiently by mixed alkali of NaOH and Na 2 CO 3 at 750 °C for 2 h. For prepared zeolite Y, the composition, phase structure, morphology, specific surface areas and ammonium adsorption were evaluated comprehensively. The results show that a single phase zeolite Y with octahedral structure and an average diameter of 2.5 μm is obtained. The Brunauer–Emmett–Teller surface area is as high as 503.34 m 2 /g. Ammonium adsorption isotherm model on obtained zeolite Y was more consistent with the Langmuir model ( R 2  > 0.99). And the maximum adsorption capacity is 18.6 mg/g. It can be concluded that the study provides an economic process to utilize fly ash for the synthesis of zeolite Y, which is an excellent adsorbent to remove ammonium. In addition, this study provides an eco‐friendly approach to synthesize low‐cost zeolite Y from solid waste, which is of excellent adsorption for ammonium removal.