Synthesis Of Monolithic Microporous Zeolite By Dry-gel Conversion Method

Molecular sieves have a wide range of applications in the field of catalysis and gas separation,because of their unique pores structure,larger specific surface area,better thermal stability and shape selectivity.Synthesis and performance development of molecular sieves is still hot spots in few decades of research.In general,the synthetic molecular sieves is universally crystalline powder,whereas it requires adding the binder during molding process which may affect the performance of the molecular sieves.In addition,synthesis method of molecular sieves generally used hydrothermal synthesis,waste water and organic pollutants are inevitable.Dry gel conversion method can minimize the use of waste water and organic templating agents to reduce environmental pollution.Moreover,the development of synthesis monolithic molecular sieve by dry-gel conversion can be removed from the use of forming adhesives,improve the molecular sieves active ingredient content,and avoid the impact of binder on molecular sieve coating performance.In this paper,the preparation of monolithic SSZ-13 and mixed ion NaKA molecular sieves were introduced.The effects of synthesis ratio and crystallization conditions on the synthesis were studied systematically.The effects of mixed structural-directing were investigated which including chrome chloride and N,N,N-trimethyl-1-adamantane ammonium hydroxide on the SSZ-13 molecular sieves.Compared with the traditional hydrothermal method,the crystallization temperature is reduced and the crystallization time is obviously shortened.The effects of NaKA molecular sieves on the synthesis ratio and crystallization conditions of NaKA zeolites also were investigated.The addition of K⁺ions in the synthesis process effectively adjusted the pore size of molecular sieves and obtained mixed ionic adsorbents with similar molecular dynamics of methane.In the first chapter,the development history of Zeolite molecular sieves and the synthesis of molecular sieves are reviewed.The second chapter focuses on the factors that affect the synthesis of SSZ-13 molecular sieves and the filling of mixed template,and the catalytic effect of MTO Inspection.In third chapter,the influencing factors of NaKA zeolite synthesized by dry gel conversion were introduced,and the application of CH4/CO2 adsorption separation was also carried out.The fourth chapter summarizes the problem of synthetic molecular sieves in the gel and makes a prospect for realizing the industrialization prospect.SSZ-13 molecular sieve is a kind of silicon aluminum molecular sieve which is widely used in MTO and NH₃-SCR reaction.It has the advantages of higher yield,lower pollution and cost.It is economical and environment-friendly for its industrial application with a double benefit.NaA molecular sieves have a wide range of applications in the field of adsorption and separation.Direct synthesis of mixed ionic NaKA molecular sieves is of great significance for the precise separation of molecules with similar molecular dynamics（such as methane,carbon dioxide,nitrogen,etc.）.