Study On Synthesis Of SUZ-4 And ZSM-35 Molecular Sieves

With the emphasis of the international maritime organization(IMO)on the supervision and management of the emission of atmospheric pollutants from ships,the implementation plan of the global Marine fuel sulfur restriction order,and the regulation of green vessels in inland waters,it is imperative to develop green environmental protection materials.The SUZ-4 molecular sieve is a novel microporous silicalite with a strong B acid site,it can convert NO/NOx into non-polluting gas and produce dimethyl ether with methanol gas-phase dehydration catalyst.The ZSM-35 molecular sieve is a high-silicon synthetic zeolite molecular sieve with FER topology,and it is specifically used in catalytic processes such as polymerization,cracking and isomerization.Therefore,this article hopes to achieve the purpose of environmental protection by exploring the preparation of SUZ-4 and the green synthesis of ZSM-35 molecular sieve.By investigating 5 kinds of aluminum sources(such as:pseudo-boehmite,imported aluminum hydroxide,aluminum sulfate,aluminum nitrate and aluminum triisopropoxide)and 4 kinds of silicon sources(such as:Ludox-AS-40,AS-40,domestic SI-30 and industrial grade SI-30),it is found that the SUZ-4 molecular sieve with high crystallinity can be obtained by taking industrial grade SI-30 as the silicon source and aluminum triisopropoxide as the aluminum source.By studying the effects of SiO2/Al2O3,TEAOH/SiO2,KOH/SiO2 and H2O/SiO2 on the synthesis of SUZ-4 molecular sieve,it was found that only when these components in the system were in a reasonable range could the corresponding molecular sieve be successfully synthesized.In addition,this paper also studied the synthesis of ZSM-35 molecular sieve without template and seedless method,and investigated the effect of crystallization temperature,SiO2/Al2O3,KOH/SiO2 and H2O/SiO2 on ZSM-35 molecular sieve.The results showed that ZSM-35 molecular sieve could be synthesized when the the initial gel composition molar ratio was SiO2/Al2O3=35-43.3,KOH/SiO2=0.23-0.41,H2O/SiO2=24.1-34.2,the crystallization temperature was 130℃-170℃,and the crystallization time was 2-8 days.Further exploring the structure-directing effect of alkali metal ions(such as Na+,K+)on the ZSM-35 molecular sieve,it was found that the ZSM-35 molecular sieve can be synthesized only under the condition of K+.