改性方法对HZSM-5分子筛孔结构、酸性质及乙醇脱水制乙烯催化性能的影响

发布时间：2018-07-28 13:40

【摘要】：对商用HZSM-5分子筛采用高温热处理、水蒸气处理及碱处理改性,制备了具有介孔结构的改性HZSM-5分子筛。采用X射线衍射、等离子体元素分析、扫描电镜、N2吸附-脱附、氨-程序升温脱附等方法对改性前后的分子筛进行表征,考察了高温热处理、水蒸气处理和碱处理3种改性方法对HZSM-5分子筛孔结构、酸性的影响,并考察了改性催化剂乙醇脱水制乙烯催化性能。结果表明,3种改性方法在保持HZSM-5分子筛微孔结构的同时,都形成了一定量的介孔,制备了不同方法的改性HZSM-5分子筛。高温热处理、水蒸气处理及碱处理3种改性方法发生了不同程度的骨架脱Al和脱Si,影响了分子筛表面酸量及酸强度,尤其是强酸量。分子筛孔结构以及表面酸性质的调变提高了HZSM-5分子筛的催化稳定性。
[Abstract]:Modified HZSM-5 molecular sieve with mesoporous structure was prepared by high temperature heat treatment, steam treatment and alkali treatment. The molecular sieve was characterized by X-ray diffraction, plasma elemental analysis, N _ 2 adsorption and desorption under scanning electron microscope, ammonia and temperature programmed desorption. The high temperature heat treatment was investigated. The effects of steam treatment and alkali treatment on pore structure and acidity of HZSM-5 molecular sieve were investigated. The catalytic performance of the modified catalyst for dehydration of ethanol to ethylene was investigated. The results show that the three modification methods have formed a certain amount of mesoporous while maintaining the micropore structure of HZSM-5 molecular sieve, and the modified HZSM-5 molecular sieve has been prepared by different methods. Three modification methods, such as high temperature heat treatment, steam treatment and alkali treatment, took place different degrees of deAl and desification of framework, which affected the amount of acid on the surface of molecular sieve and its strength, especially the amount of strong acid. The catalytic stability of HZSM-5 molecular sieve was improved by the modification of pore structure and surface acid properties.
【作者单位】：太原理工大学化学化工学院;中国科学院山西煤炭化学研究所;
【基金】：山西省自然科学基金项目(2014011012-3)资助
【分类号】：O643.36

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