Korean Chemical Engineering Research, Vol.56, No.6, 909-913, December, 2018
A Computational Study on the Adsorption Characteristics of Hydrocarbons (Propylene, n-Butane and Toluene) by uing Cation-exchanged ZSM-5 Zeolites
A hydrocarbon trap (HT) plays an important role of controlling vehicle emissions in the so-called cold emission period by holding hydrocarbons until three way catalysts (TWCs) are thermally activated. In this study, we have investigated the adsorption characteristics of cation (H, La, K, and Ag)-exchanged ZSM-5 zeolites for hydrocarbons (propylene, n-butane, and toluene) by DFT (density functional theory)-based computational chemistry. Cation exchange is to improve the hydrothermal stability of zeolites and their adsorption capacity, thereby rendering cationexchanged zeolites promising materials for HT. The idea of cluster approximation makes the calculation of adsorption energies superbly efficient in computation. The results showed that Ag-exchanged ZSM-5 would be the best for the adsorption of all three adsorbates, without often encountered Ag oxidation in experiments. Besides, the hydrothermal stability of La-exchanged ZSM-5 was confirmed from the change of geometrical parameters by cation exchange, and it showed good adsorption capacity for propylene and toluene. Hydrogen-exchanged ZSM-5 was also good for hydrogen adsorption, but had poor hydrothermal stability.
Keywords:ZSM-5;Cation Exchange;Hydrocarbon Trap (HT);Density Functional Theory;Cluster Approximation
- Sanz O, Delgado JJ, Navarro P, Arzamendi G, Gandia LM, Montes M, Appl. Catal. B: Environ., 110, 231 (2011)
- Maupin I, Mijoin J, Barbier J, Bion N, Belin T, Magnoux P, Catal. Today, 176(1), 103 (2011)
- http://www.compass.or.kr (Compliance in Advance and Supporting Sytem).
- Higashiyama K, Nagayama T, Nagano M, Nakagawa S, J. Fuels Lubricants, 112, 499 (2003)
- Noda N, Takahashi A, Mizuno H, “In-line Hydrocarbon (HC) Adsorber System for Reducing Cold Start Emissions,” Society of Automotive Engineers, Technical paper, 2000-01-0892(2000).
- Seo G, “First Step of Zeolites,” Chonnam University (2005).
- Li HF, Shen BJ, Wang XH, Shen SK, Catal. Lett., 99(3-4), 165 (2005)
- Pieterse JAZ, Pirngruber GD, van Bokhoven JA, Booneveld S, Appl. Catal. B: Environ., 71(1-2), 16 (2007)
- Liu XS, Lampert JK, Arendarskiia DA, Farrauto RJ, Appl. Catal. B: Environ., 35(2), 125 (2001)
- He X, Huang X, Wang Z, Yan Y, Micro. Meso. Mater., 142, 398 (2011)
- Ines T, Silvia I, Pedro P, Carlos T, Joaquı´n C, Jesus S, J. Phys. Chem. C, 111, 4702 (2007)
- Busco CA, barbaglia M, broyer B, Bolis GMF, Ugliengo P, Thermochemica Acta, 418, 3 (2004)
- Ivanov AV, Graham GW, Shelef M, Appl. Catal. B: Environ., 21(4), 243 (1999)
- Zheng A, Liu SB, Deng F, Macro. Micro. Mater., 121, 158 (2009)
- Jiang S, Huang S, Qin L, Tu W, Zhu J, Tian H, Wang P, J. Mol. Sci.: THEOCHEM, 962, 1 (2010)
- Won YS, Lee J, Kim CS, Park SS, Surf. Sci., 603, L31 (2009)
- Li Y, Liu H, Zhu J, He P, Wang P Tian H, Micro. Macro. Mater, 142, 621 (2011)