Solvent-free preparation of hierarchical 4A zeolite monoliths: Role of experimental conditions

A series of novel self-supporting hierarchically porous zeolite monoliths with micropores and macropores were successfully prepared using polymethyl methacrylate (PMMA) microbeads as sacrificial template via solvent-free strategy. The effects of several synthesis parameters, such as Na/Al molar ratio, H2O/metakaolin (MK) mass ratio, MK/PMMA mass ratio and curing time on the structure and morphology of hierarchical zeolite monoliths were systematically investigated. Multiple techniques, including SEM, XRD, FTIR, XRF, BET, MIP and TG-DTG were used to test the properties of resultant products. The experimental results show that hierarchical 4A zeolite monoliths could be obtained at Na/Al molar ratio of 1.2:1, H2O/MK mass ratio of 1.1:1, MK/PMMA mass ratio of 50/50, curing temperature of 70 degrees C for 24 h and calcination temperature of 550 degrees C for 2 h. The SiO2/Al2O3 molar ratio and BET specific surface area were found to be 1.92 and 57.67 m(2)/g, respectively. The diameter of macropore pores were mainly in the range of 840-4130 nm.