Synthesis of high-quality Na\\P1 zeolite from municipal solid waste incineration fly ash by microwave-assisted hydrothermal method and its adsorption capacity

The Si and Al in municipal solid waste incineration fly ash (MSWI FA) can be utilized for zeolite fabrication, which can improve the application value of the products. This study focuses on the fabrication of zeolite from MSWI FA by microwave-assisted hydrothermal (MH) treatment. The effects of magnetic stirring time, Na2SiO3 dosage, MH time, and NaOH solution concentration on the crystallization of zeolite Na\\P1 from MSWI FA are systematically analyzed. The synthetic products are analyzed through spectroscopic and mineralogical methods. The results show that zeolite Na\\P1 with high crystallinity (51.68%) can be fabricated by magnetic stirring and MH treatment, and the cation exchange capacity (CEC) of the product can reach a value of 2.58 meq/g, which is approximately 133 times that of the CEC of MSWI FA. The Si/Al ratio plays a decisive role in the zeolite Na\\P1 synthesis, and a Na2SiO3 dosage of 30 wt% is adopted for zeolite Na\\P1 fabrication. A NaOH concentration of 1 M is sufficient for zeolite Na\\P1 synthesis. Additionally, the zeolite Na\\P1 content is found to obviously increase with increasing MH time from 0.5 h to 2 h. To demonstrate the feasibility of the method provided in this study, the optimal experimental condition is employed for various MSWI FAs, and zeolite Na\\P1 and analcime are fabricated successfully. The leachability of heavy metals for the synthetic products was evaluated, which met the requirements for pollution control. The BET surface area and total pore volume of zeolite Na\\P1 fabricated at optimal condition are 61.42 m(2)/g and 0.44 cm(3)/g, respectively. The adsorption capacity of zeolite Na\\P1 for Cu2+ ion and methylene blue are determined to be 84.65 mg/g and 84.55 mg/g, respectively, indicating zeolite Na\\P1 is a potential adsorbent for cation ion and dyes. This study provides an environmentally friendly scheme for the utilization of MSWI FA.

Automated summary

This study focuses on the fabrication of zeolite from municipal solid waste incineration fly ash (MSWI FA) using microwave-assisted hydrothermal treatment. It systematically analyzes the effects of various factors on the crystallization of zeolite from MSWI FA. The results demonstrate that zeolite with high crystallinity can be successfully synthesized using magnetic stirring and microwave-assisted hydrothermal treatment. Additionally, the synthetic zeolite exhibits excellent adsorption capacity for heavy metals and dyes.