厚壁MCM-41中孔分子筛的合成

在水热条件下，以硅酸钠、活性氧化铝为硅源和铝源，表面活性剂ＣＴＭＡＢ为结构模板剂，对合成过程的凝胶组成、晶化温度、晶化时间等因素进行正交试验，成功地合成出相对结晶度高的厚壁ＭＣＭ－４１中孔分子筛材料。采用ＸＲＤ、低温Ｎ２吸附（ＢＥＴ）等测试手段对合成的ＭＣＭ－４１样品进行表征。考察了影响ＭＣＭ－４１孔壁厚度的主要因素。结果表明，向体系中加入适量的稀硫酸和有机酸，有效地控制了体系的ｐＨ，提高了ＭＣＭ－４１的相对结晶度和孔壁厚度。通过优化合成条件，合成出孔径３１８ｎｍ、比表面大于１０００ｍ２·ｇ－１、孔壁厚度２８２ｎｍ的ＭＣＭ－４１中孔分子筛。

Synthesis of Thick Pore Wall MCM-41 Mesoporous Molecular Sieves

The effects of gel composition,crystallizing temperature and time on the relative crystallinity of MCM-41 were investigated in a hydrothermal system using sodium silicate as silica source,active alumina as aluminum source and surfactant CTMAB as structural template.The synthesis of mesoporous molecular sieve MCM-41 of high relative crystallinity was accomplished under optimum conditions.X-ray diffraction and low temperature nitrogen adsorption were used to characterize the synthesized MCM-41.The primary factors affecting pore wall thickness of MCM-41 were investigated.An increase in relative crystallinity and pore wall thickness of MCM-41 molecular sieve results from properly adding dilute sulfuric acid and organic acid to the reaction system,which effectively controls the pH of the system.It has been found that the MCM-41 synthesized has a pore diameter of 3 18 nm,a BET surface area of larger than 1000 m 2·g -1 and a pore wall thickness of 2 82 nm.