Atomistic simulation of nanoporous layered double hydroxide materials and their properties. II. Adsorption and diffusion

被引:25
作者
Kim, Nayong [1 ]
Harale, Aadesh [1 ]
Tsotsis, Theodore T. [1 ]
Sahimi, Muhammad [1 ]
机构
[1] Univ So Calif, Mork Family Dept Chem Engn & Mat Sci, Los Angeles, CA 90089 USA
基金
美国国家航空航天局;
关键词
D O I
10.1063/1.2799985
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Nanoporous layered double hydroxide (LDH) materials have wide applications, ranging from being good adsorbents for gases (particularly CO2) and liquid ions to membranes and catalysts. They also have applications in medicine, environmental remediation, and electrochemistry. Their general chemical composition is [(M1-xMxIII)-M-II(OH-)(2)](x+)[X-n/m(m-)center dot nH(2)O], where M represents a metallic cation (of valence II or III), and X-n/m(m-) is an m-valence inorganic, or heteropolyacid, or organic anion. We study diffusion and adsorption of CO2 in a particular LDH with M-II=Mg, M-III=Al, and x similar or equal to 0.71, using an atomistic model developed based on energy minimization and molecular dynamics simulations, together with a modified form of the consistent-valence force field. The adsorption isotherms and self-diffusivity of CO2 in the material are computed over a range of temperature, using molecular simulations. The computed diffusivities are within one order of magnitude of the measured ones at lower temperatures, while agreeing well with the data at high temperatures. The measured and computed adsorption isotherms agree at low loadings, but differ by about 25% at high loadings. Possible reasons for the differences between the computed properties and the experimental data are discussed, and a model for improving the accuracy of the computed properties is suggested. Also studied are the material's hydration and swelling properties. As water molecules are added to the pore space, the LDH material swells to some extent, with the hydration energy exhibiting interesting variations with the number of the water molecules added. The implications of the results are discussed. (c) 2007 American Institute of Physics.
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页数:12
相关论文
共 90 条
[1]   Delamination of layered double hydroxides by use of surfactants [J].
Adachi-Pagano, M ;
Forano, C ;
Besse, JP .
CHEMICAL COMMUNICATIONS, 2000, (01) :91-92
[2]   Cu/Ni/Al layered double hydroxides as precursors of catalysts for the wet air oxidation of phenol aqueous solutions [J].
Alejandre, A ;
Medina, F ;
Rodriguez, X ;
Salagre, P ;
Cesteros, Y ;
Sueiras, JE .
APPLIED CATALYSIS B-ENVIRONMENTAL, 2001, 30 (1-2) :195-207
[3]   Intercalation compounds of hydrotalcite-like anionic clays with antiinflammatory agents - I. Intercalation and in vitro release of ibuprofen [J].
Ambrogi, V ;
Fardella, G ;
Grandolini, G ;
Perioli, L .
INTERNATIONAL JOURNAL OF PHARMACEUTICS, 2001, 220 (1-2) :23-32
[4]   Reduction of 4-nitrotoluene over Fe-Mg-Al lamellar double hydroxides [J].
Auer, SM ;
Grunwaldt, JD ;
Köppel, RA ;
Baiker, A .
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL, 1999, 139 (2-3) :305-313
[5]   Oxidative dehydrogenation of propane over calcined vanadate-exchanged Mg,Al-layered double hydroxides [J].
Bahranowski, K ;
Bueno, G ;
Corberán, VC ;
Kooli, F ;
Serwicka, EM ;
Valenzuela, RX ;
Wcislo, K .
APPLIED CATALYSIS A-GENERAL, 1999, 185 (01) :65-73
[6]  
Berendsen H. J. C., 1981, INTERMOLECULAR FORCE, P331, DOI [DOI 10.1007/978-94-015-7658, DOI 10.1007/978-94-015-7658-1_21]
[7]   The intercalation of carboxylic acids into layered double hydroxides: A critical evaluation and review of the different methods [J].
Carlino, S .
SOLID STATE IONICS, 1997, 98 (1-2) :73-84
[8]   Monte Carlo and molecular dynamics simulations of electrical double-layer structure in potassium-montmorillonite hydrates [J].
Chang, FRC ;
Skipper, NT ;
Sposito, G .
LANGMUIR, 1998, 14 (05) :1201-1207
[9]  
Crank J., 1975, The Mathematics of Diffusion, V1
[10]   Molecular models of hydroxide, oxyhydroxide, and clay phases and the development of a general force field [J].
Cygan, RT ;
Liang, JJ ;
Kalinichev, AG .
JOURNAL OF PHYSICAL CHEMISTRY B, 2004, 108 (04) :1255-1266