Synthesis And Characterization Of Microporous/Mesoporous Molecular Sieves Of Y/SBA-15

(1) Molecular Sieves with dual-mode micro-mesoporous structure have many advantages and potential applications because of the adjustable pore size and strong acidic property. In this paper, Y/SBA-15complex molecular sieve with regular-morphology and orderly-uniform pore distribution were synthesized by nano-assembly and in-situ degradation in a simpler method, And the assembly behaviours of zeolite precursors in different routes were investigated. Composite molecular sieve with graded pores and ordered structure obtained in this thesis would throw a light on the industrial application of meoporous zeolites.The research content in this thesis includes three sections:(2) In hydrochloric acid medium, Y zeolite was added directly to the precursor solution, then Y/SBA-15composite molecular sieve was synthesized by one-step crystallization.with typical hexagonal mesoporous structure, the material is a single phase rather than a mixed phase of the microporous and mesoporous. Various factors effected on the synthesis of Y/SBA-15were studied systematically and the optimal synthesis condition were obtained:the adding amount of Y zeolite was0.5g,the initial concentration of hydrochloric acid was1mol/L,the reaction time was24h, the crystallization temperature was100℃, the crystallization time24h. conclusions were obtained by systematic characterizations of the molecular sieve. BET surface area was595.4m2/g, pore volume was0.75cm3/g, and average pore diameter was6.7nm.(3) The synthesis of mesoporous molecular sieves has been made public using phosphate acid as a mild medium. Y/SBA-15were synthesized by nano-assembly in mild medium of phosphate acid. Related factors effected on the synthesis of Y/SBA-15were studied systematically,the optimal synthesis conditions were obtained:the initial concentration of H3PO4was2mol/L,the adding amount of P123was1.0g, the adding amount of Y zeolite was0.5g, the reaction time was18h, the crystallization temperature was100℃the crystallization time24h. SEM and TEM results showed that the pores tructure was ordered and long-range ordered.N2adsor-desorption and BET imagines suggested that Y/SBA-15had microporous and mesoporous structures, surface area up to547.3m2/g, pore volume was0.66cm3/g, average pore diameter was6.06nm.(4) The degradation method,by dissolving the zeolite under acidic or basic conditions to obtain a precursor of the microporous molecular sieve, provide a good research ideas on synthesising of composite molecular sieve.In this thesis,Y-SBA-15was obtained by the degradation of Y zoelies.the optimal synthesis condition were obtained:the amount of degradation solution was30ml,the initial gel pH was1.0,the reaction temperature was15℃, the crystallization temperature was120℃. SEM imagines suggested that the pores tructure was ordered and long-range ordered. BET surface area was486.m2/g, pore volume was0.37cm3/g, average pore diameter was3.7nm.