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乙烯在丝光沸石和改性丝光沸石孔道内的吸附行为
  • ISSN号:1000-6818
  • 期刊名称:《物理化学学报》
  • 时间:0
  • 分类:O647.3[理学—物理化学;理学—化学]
  • 作者机构:[1]兰州大学化学化工学院,兰州730000, [2]辽宁石油化工大学辽宁省石油化工重点实验室,辽宁抚顺113001
  • 相关基金:国家自然科学基金(20546003)资助项目
中文摘要:

采用频率响应(FR)法研究乙烯在丝光沸石和经CuO和Cs^+离子改性的丝光沸石上的吸附机理.分别测得和解析了252和273K、压力在26.6-3990Pa范围内的FR谱图,发现乙烯在丝光沸石上吸附的速控步骤是传质过程,同时存在两个不同的吸附过程.这两个过程分别归属于乙烯在质子酸吸附中心上的吸附(低频吸附)和Na^+吸附位上的吸附(高频吸附),252K时两个吸附位的吸附值分别是0.692和0.828mmol·g^-1.CuO分子进入分子筛孔道后,位于质子酸吸附位之间不但使得低频吸附位值增加而且还覆盖了Na^+吸附位,体系中以化学吸附过程为主;Cs^+离子的引入使得高频吸附位值增加但中和了质子酸吸附位,体系中以物理吸附过程为主.CuO的最佳用量是5%.将FR法与吸附等温线及Langmuir模型相结合能够深入研究乙烯在分子筛上的平行吸附过程.

英文摘要:

The frequency response (FR) technique were applied to study adsorption mechanism of ethene on parent mordenite and the mordenite modified by CuO and Cs^+. The FR spectra of ethene on parent mordenite and modified mordenite were recorded and analyzed at temperature of 252 and 273 K and in the pressure range of 26.6-3990 Pa. The results showed that adsorption of ethene was the rate controlling step and there were two parallel adsorption processes in ethene/parent mordenite system. Those two processes were attributed to adsorption process of ethene on proton acid sites (low frequency adsorption) and on sodium cation sites (high frequency adsorption), and the numbers of sites available for adsorption of ethene were 0.692 and 0.828 retool· g^-1, respectively. The number of adsorption sites in low frequency adsorption was increased by the introduction of CuO, which was located among the proton acid sites and covered the sodium cation sites in high frequency adsorption. Chemical adsorption was the main sorption process in mordenite channels modified by CuO. The number of adsorption sites in high frequency adsorption was increased by the introduction of Cs^+, which counteracted proton acid sites in low frequency adsorption. Physical adsorption was the main sorption process in mordenite channels modified by Cs^+. The effective mass fraction of CuO for modification was 5%. The ethene adsorption processes on zeolites can be studied in detail by combining the FR spectra, isotherms, and Langmuir model.

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期刊信息
  • 《物理化学学报》
  • 中国科技核心期刊
  • 主管单位:中国科学技术协会
  • 主办单位:北京大学化学与分子工程学院承办
  • 主编:刘忠范
  • 地址:北京大学化学楼
  • 邮编:100871
  • 邮箱:whxb@pku.edu.cn
  • 电话:010-62751724
  • 国际标准刊号:ISSN:1000-6818
  • 国内统一刊号:ISSN:11-1892/O6
  • 邮发代号:82-163
  • 获奖情况:
  • 中文核心期刊
  • 国内外数据库收录:
  • 俄罗斯文摘杂志,美国化学文摘(网络版),荷兰文摘与引文数据库,美国科学引文索引(扩展库),英国科学文摘数据库,日本日本科学技术振兴机构数据库,中国中国科技核心期刊,中国北大核心期刊(2004版),中国北大核心期刊(2008版),中国北大核心期刊(2011版),中国北大核心期刊(2014版),英国英国皇家化学学会文摘,中国北大核心期刊(2000版)
  • 被引量:24781