采用水热合成法制备低硅铝比X型分子筛(LSX),通过离子改性法研究了离子种类、交换次数等制备Rb-LSX的最佳条件。利用单组分和多组分吸附实验探究吸附时间、溶液浓度等对C₈芳烃吸附分离的影响,并对其进行吸附动力学、吸附等温线和吸附扩散性能研究。结果表明,在298 K下,单组分吸附实验中C₈芳烃在Rb-LSX上的吸附量大小为:乙苯(EB,162.05 mg/g)>对二甲苯(PX,141.00 mg/g)>间二甲苯(MX,128.67 mg/g)>邻二甲苯(OX,125.02 mg/g),且Rb-LSX对4种芳烃分子的吸附过程符合Langmuir等温线模型和准二级动力学模型;在多组分吸附实验中,EB/PX、EB/MX和EB/OX的选择性分别为6.94、5.41、7.20;C₈芳烃分子在Rb-LSX分子筛中的扩散能力大小为:EB>MX>PX>OX。

LSX,a X-type zeolite with low Si-Al ratio,is prepared via hydrothermal synthesis method.The optimum preparation conditions for Rb-LSX,including the types of ions and exchange frequences,are studied through ion modification method.The impacts of adsorption time and solution concentration on the adsorption and separation of C₈ aromatics are explored by means of single-component and multi-component adsorption experiments,and the adsorption kinetics,adsorption isotherm and adsorption diffusion properties are studied.Results show that the adsorption capacity of C₈ aromatic hydrocarbons on Rb-LSX at 298 K is in the following order:ethylbenzene (EB,162.05 mg·g^-1)>p-xylene (PX,141.00 mg·g^-1)>m-xylene (MX,128.67 mg·g^-1)>o-xylene (OX,125.02 mg·g^-1).Moreover,the adsorption process of Rb-LSX for these four aromatics is consistent with Langmuir isotherm model and quasi-second-order kinetic model.In the multi-component adsorption experiment,the selectivity rates of EB/PX,EB/MX and EB/OX are 6.94,5.41 and 7.20,respectively.The diffusion capacity of C₈ aromatic molecules in Rb-LSX molecular sieve is in order of EB>MX>PX>OX.

赵可心(2000-),女,硕士生,研究方向为C₈芳烃吸附分离,y82210147@mail.ecust.edu.cn;刘纪昌(1981-),男,博士,教授,研究方向为分子筛及MOFs等多孔材料的合成与吸附分离,通讯联系人,liujc@ecust.edu.cn。