Sorption of water vapor on HZSM-5 type zeolites

Sano, T.; Kasuno, Takekazu; Takeda, Kunihiko; Arazaki, S.; Kawakami, Yusuke

doi:10.1016/s0167-2991(97)80642-8

Cited by 31 publications

(20 citation statements)

References 17 publications

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“…The hydration number of the sodium cation, 3.5 molecules/cation, was determined by extrapolating the plateau region of the adsorption isotherm to zero. 8,16 This value was slightly smaller than the previously reported hydration number, 4.4 molecules/ cation, for sodium cations in bulk solution. 17 The sodium cations in the ZSM-5 structure would exist in the pores near the [¸Si OAl¸] framework, as in H-ZSM-5.…”

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confidence: 64%

Study of Water Adsorption on Hydrophobic Na-ZSM-5 and H-ZSM-5 by Directly Measuring Adsorption Isobars and Isotherms

et al. 2012

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The effects of different cation species on water adsorption on hydrophobic ZSM-5 zeolite are investigated through adsorption isotherm and isobar measurements. The adsorption isobars clearly show that sodium cations behave as stronger water adsorption sites than do protons. Furthermore, the adsorption isotherms of Na-and H-zeolites show such differences at part of the hysteresis loop. This suggests that the cation species in ZSM-5 affect the formation of the first, second, and third hydration shells in the hydrophobic space.Recently, there has been much focus on making improvements to microscopic measurement techniques and developing new methods for synthesizing porous materials. Microscopic measurement methods such as X-ray diffraction (XRD) 1 and extended X-ray absorption fine structure (EXAFS) 2 enable the study of the behavior of adsorbed molecules. New porous materials such as metalorganic frameworks (MOFs) 3 and porous organosilicates 4 have designable nanostructures. Using these new techniques and materials, we developed a method for controlling the pore structure and elucidating the molecular behavior in nanospaces. However, macroscopic measurements of the adsorbed amount, heat of adsorption, etc., are also important for the development of porous materials with new properties and functions.In adsorption studies, the adsorbed amount, which can be determined from adsorption isotherms by conventional gravimetric or volumetric analyses, is considered the most important macroscopic property. Adsorption isotherms have been frequently used to investigate the microscopic properties of porous materials since suitable measurement methods and the isothermal adsorption theory 57 have been well established. However, the information obtained by adsorption isotherm measurements is inadequate because the isotherms do not include the effects of temperature changes. Therefore, isobaric adsorption measurements are necessary. Adsorption isobars are typically measured using an indirect method that involves the measurement of many adsorption isotherms. However, this method cannot be applied to investigate the hysteresis during adsorbate loading. Therefore, we have developed a direct method for measuring adsorption isobars, using a high-speed feedback electrical circuit that helps in maintaining a constant pressure.In this study, we investigated the water adsorption on hydrophobic ZSM-5, a well-known microporous adsorbent and catalyst that finds numerous applications in different industrial fields.8,9 Although ZSM-5 is hydrophobic, its micropore structure contains adsorption sites that show strong interactions with polar molecules: an interesting advantage of ZSM-5.There are many reports on the behavior of water molecules inside hydrophobic nanospaces (e.g., in activated carbon). On the basis of XRD data, Kaneko, Iiyama, et al. suggested that water molecules confined in activated carbon form cluster-like assemblies.10 Gubbins et al. investigated the importance of hydrophilic adsorption sites in the formation of such assemblies ...

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confidence: 64%

Study of Water Adsorption on Hydrophobic Na-ZSM-5 and H-ZSM-5 by Directly Measuring Adsorption Isobars and Isotherms

et al. 2012

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“…15 illustrates the XRD patterns of MCM-41 powder under varying exposure time to KOH electrolyte within the stated weight ratio %. There is no obvious change in the intensity of the (1 0 0) peak which suggests that there is no significant effect of KOH on the lattice structure [15,16]. On the other hand for comparison, Fig.…”

Section: Resultsmentioning

confidence: 92%

“…The surface area and pore volume can be modified through silylation treatment [19,20]. Whereas the pore width is tuneable from nanopore to micropore sizes by selecting a suitable organic template and undergoing post synthesis treatment such as adding the alkyl accessories [16,19]. Besides, the hydrophilic nature of the assynthesized MCM-41 which is due to its isolated silanol groups, can be tuned into a hydrophobic type by adding the alkyl group during the synthesis [16,19,20].…”

Section: Resultsmentioning

confidence: 99%

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MCM-41 as a new separator material for electrochemical cell: Application in zinc–air system

Saputra

Othman

Sutjipto

et al. 2011

Journal of Membrane Science

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“…The oxygen‐silicon tetrahedron is nonpolar whereas the oxygen‐aluminum tetrahedron is polar and shows certain hydrophilicity 26. In this case, the higher the content of aluminum, the higher degree of hydrophilicity 26–31. A series of Al MAS NMR (magic angle spinning nuclear magnetic resonance) tests are conducted to verify the trend of variation of Al content in the ZSM‐5 framework upon different pretreatment temperatures, and the results are shown in Figure 4.…”

Section: Resultsmentioning

confidence: 99%

Experimental Study on Energy Dissipation Characteristics of ZSM‐5 Zeolite/Water System

Sun

et al. 2013

Adv Eng Mater

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Research and development of new materials with high energy dissipation density is one of the key approaches to promote the automotive crash safety. [1,2] Conventional energy dissipation materials and structures based on metal plastic deformation, [3] buckling of cellular truss or foam, [4] damping of polymers, [5] internal friction of textile composites, [6] and phase transformation [7] are employed to achieve the energy desired dissipation goal. Most materials developed so far, however, have relatively low energy dissipation performance in terms of the unit mass/volume consideration, and most of them are not reusable. Therefore, reusable, high-density energy dissipation material candidates are in pressing need for industries.Nanomaterial is considered and proven to be a promising alternative to these traditional materials, [8][9][10][11] among which an innovative nanoporous material energy absorption system (NEAS) was recently established [12] where a nanoporous material and liquid are combined with controllable wetting properties. In essence, NEAS takes advantage of the ultralarge surface area of nanoporous material and during the liquid infiltration process, it converts the external mechanical energy into the excessive solid-liquid interfacial energy and frictional heat. The wetting characteristic, which dominates the infiltration/defiltration and flow behaviors of liquid molecules, can be adjusted via various approaches, including COMMUNICATIONInteraction with liquids at the ultra-large surface area of nanoporous material enables a high-efficiency energy dissipation system with wide perspective applications [A. Han, et al., Langmuir 2008, 24, 7044]. In this paper, a nanoporous energy dissipation system composed of a mixture of zeolite ZSM-5 and water is established and studied experimentally. Firstly, quasi-static compression experiments are carried out to analyze the pressure-volume curve and reveal the energy dissipation mechanism. Afterwards, a parametric study is conducted to explore the effects of three parameters, the pretreatment temperature of zeolite ZSM-5 (600-1100 8C), mass ratio of ZSM-5 to water (1:5-6:5), and average zeolite particle size (2.145-5.251 mm before heated or 6.104-9.557 mm after heated). Results show that in order to obtain optimum energy absorption performance, the pretreatment temperature of about 1000 8C, and higher ratio of ZSM-5 with larger particle size are desired. With high energy dissipation and reusability, the zeolite-water system with optimal parameters established herein may become an attractive cushioning device. 740 wileyonlinelibrary.com ß

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Sorption of water vapor on HZSM-5 type zeolites

Cited by 31 publications

References 17 publications

Study of Water Adsorption on Hydrophobic Na-ZSM-5 and H-ZSM-5 by Directly Measuring Adsorption Isobars and Isotherms

Study of Water Adsorption on Hydrophobic Na-ZSM-5 and H-ZSM-5 by Directly Measuring Adsorption Isobars and Isotherms

MCM-41 as a new separator material for electrochemical cell: Application in zinc–air system

Experimental Study on Energy Dissipation Characteristics of ZSM‐5 Zeolite/Water System

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