离子交换法合成L/MCM-41复合分子筛

Synthesis of Micro/meso-porous Composite Molecular Sieve L/MCM-41 with Ion Exchange

以十六烷基三甲基溴化铵(CTAB)为模板剂,分别采用包埋法和离子交换法,两步晶化都合成了L/MCM-41复合分子筛,并通过XRD、SEM、TEM和BET等测试手段对合成样品进行表征,检测结果表明用离子交换法合成的复合分子筛孔径为3.04 nm.与水热晶化法合成的MCM-41相比:(1)壁厚由0.55 nm增大到1.81 nm;(2)水热稳定性也明显提高,在100℃沸腾状态下结构保持时间由原来的低于2 h增大到8 h.与L沸石相比,K+含量降低为0.26%.

Micro/meso-porous composite molecular sieve L/MCM-41 was synthesized with embedding method and ion exchange using cetyl trimethyl ammonium bromide（CTAB） as template and it was confirmed by being characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,transmission electronic microscopy（TEM） and N2 absorption/ desorption.The results indicated that the pore diameter of L/MCM-41 composite molecular sieve was 3.04 nm which was bigger than that of microporous molecular sieves.Compared with MCM-41 molecular sieve synthesized by ordinary hydrothermal method： 1）the pore wall thickness increased from 0.55 nm to 1.81 nm;2） The hydrothermal stability improved significantly,the structure could keep unchanged for 8h,rising by 6 h,at 100 ℃.Compared with zeolite L,the content of K＋ decreased from 18.42% to 0.98%.