A review of the synthesis and application of zeolites from coal-based solid wastes

Zeolite derived from coal-based solid wastes (coal gangue and coal fly ash) can overcome the environmental problems caused by coal-based solid wastes and achieve valuable utilization. In this paper, the physicochemical properties of coal gangue and coal fly ash are introduced. The mechanism and application characteristics of the pretreatment processes for zeolite synthesis from coal-based solid wastes are also introduced. The synthesis processes of coal-based solid waste zeolite and their advantages and disadvantages are summarized. Furthermore, the application characteristics of various coal-based solid waste zeolites and their common application fields are illustrated. Finally, we propose an alkaline fusion-assisted supercritical hydrothermal crystallization as an efficient method for synthesizing coal-based solid waste zeolites. In addition, more attention should be given to the recycling of alkaline waste liquid and the application of coal-based solid waste zeolites in the field of volatile organic compound adsorption removal.