Static hydrothermal crystallization of SUZ-4 zeolite in the presence of seed and tetraethylammonium hydroxide

The static hydrothermal synthesis of SUZ-4 zeolite with the assistance of crystalline seed and using tetraethylammonium hydroxide (TEAOH) as the structure-directing agent (SDA) was studied systematically. The key synthesis parameters, such as reactant molar ratios, seed amount, and crystallization time were changed to optimize the synthesis conditions. The products were characterized by XRD, SEM, N2 adsorption and ICP elemental analysis. The results show that the seed-aided TEAOH-templated hydrothermal approach leads to the formation of SUZ-4 zeolite in a broad SiO2/Al2O3 range of 21–33. The crystallization time for creating a highly crystallized SUZ-4 phase increases with the raise of SiO2/Al2O3 ratios. Under the optimal conditions, i.e., SiO2/Al2O3 = 21, KOH/SiO2 = 0.38, TEAOH/SiO2 = 0.12, H2O/SiO2 = 23.8, seed amount = 0.1 wt.%, and static hydrothermal crystallization at 160 °C, SUZ-4 zeolite is obtained within a very short time of 1 d. The morphology of SUZ-4 is altered by TEAOH content from separated needle-like thin crystals to thick rod-like assemblies.