Abstract:

The isosteric heat of adsorption of thiophene on faujasite-type zeolites, siliceous faujasite and NaY (Si∶Al=2.43)is studied by grand canonical Monte Carlo(GCMC)simulations, with different loadings of the sorbate.The simulated results are in excellent agreement with the experimental data.The contributions of short-range and long-range interactions to the heat of adsorption are discussed and the host/guest pair distribution functions (PDFs)in the MC simulations are analyzed.The analysis on the interaction energy of host/guest shows that the short-range dispersion energy dominates the adsorption of thiophene on FAU-type zeolites.A new site is revealed for thiophene and sodium ions in NaY which is different with that in siliceous Y.The sodium ions strengthen the interaction in adsorption.Electrostatic interactions and dispersion energies between sodium ions and thiophene are important factors for the heat of adsorption.The pair distribution functions of thiophene in NaY show more details of the specific sites of thiophene in NaY.

Key words:

分子模拟, 吸附, 噻吩, 全硅Y, NaY

摘要：

采用GCMC方法计算了噻吩在全硅Y和NaY沸石上的吸附，通过变化不同的噻吩吸附量得到吸附能量的异质性，并基于主客体径向分布函数剖析了吸附能量的异质性。根据对噻吩分子与沸石之间能量的分析，噻吩分子与沸石之间的作用主要由短程的色散作用控制。NaY沸石上吸附表现出与全硅Y沸石明显不同的吸附位特征，钠离子的引入明显地增强了对噻吩的吸附作用。钠离子与噻吩之间的静电和色散作用是引起这两种不同化学组成沸石吸附热不同的重要因素。进一步对径向分布函数分析确定了NaY沸石中S—Na，CHsp2—Na之间存在独特的作用位。

关键词:

分子模拟, 吸附, 噻吩, 全硅Y, NaY