CO2 adsorption equilibria of the honeycomb zeolite beds

Kamiuto, Kouichi; Ermalina,; Ihara, Kenji

doi:10.1016/s0306-2619(01)00014-9

Cited by 6 publications

(4 citation statements)

References 2 publications

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“…When the equilibrium CO 2 pressure increases to 1 mbar, the intensity of infrared bands increases significantly and three bands appear. This shows that the amount of adsorbed CO 2 increases quickly under the low-pressure region, and this adsorption behavior is in good agreement with Langmuir adsorption law . Figure B shows that, after sequential evacuation at 298, 323, 373, 423, and 473 K, the intensity of infrared bands decreases with the increase of temperature.…”

Section: Resultssupporting

confidence: 74%

CO₂ Adsorption over Si-MCM-41 Materials Having Basic Sites Created by Postmodification with La₂O₃

2004

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Moderate basic sites could be created onto mesoporous Si-MCM-41 materials by postsynthesis modification with highly dispersed La2O3. The La2O3-modified MCM-41 materials (designated here as LaM) have been characterized by Fourier transform infrared spectroscopy, temperature-programmed desorption, X-ray photoelectron spectroscopy, X-ray diffraction (XRD), and N2 adsorption/desorption and have been tested as model adsorbents for CO2 adsorption. XRD and N2 adsorption results showed that all LaM materials still maintained their uniform hexagonal mesoporous structure even after postsynthesis modification with La2O3 loading up to 20 wt %. Although the surface area, pore size, and pore volume of LaM materials decreased with increasing La2O3 loading, their capacity for CO2 storage could be significantly improved when La2O3 loading was increased from 0 to 10 wt %. Unidentate and bidentate carbonates have been identified by in situ FTIR as the two types of CO2 species adsorbed on LaM surface. The LaM material also possesses good thermal stability, allowing the model adsorbent to be regenerated at high temperature and recyclable.

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Section: Resultssupporting

confidence: 74%

CO₂ Adsorption over Si-MCM-41 Materials Having Basic Sites Created by Postmodification with La₂O₃

2004

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“…The rate of water vapor consumption was given by the linear driving force approximation − R = k 0 false( C * − C normals false) where k 0 is the mass transfer coefficient, obtained from parameter fitting to be 5.5 × 10 –3 s –1 , C s represents the surface concentration of water on the calcium chloride surface at any given time, and C * is its equilibrium value. Equilibrium water concentration was modeled through the Dubinin–Astakhov equation approximated as − C * = C 2 0 k 1 C 1 1 + k 2 C 1 where C 2 0 represented the initial concentration of binding sites on calcium chloride available for humidity capture and k 1 and k 2 were equilibrium parameters obtained from fitting, which were 0.33 m 3 ·mole –1 and 0.01 m 3 ·mole –1 , respectively. The surface humidity concentration at any time was represented as C normals = C 2 0 − C 2 Finally, the rate of consumption was obtained as R = k 0 true[ C 2 0 * k 1 C 1 1 + k 2 C 1 …”

Section: Experimental and Simulation Methodsmentioning

confidence: 99%

Online Sample Conditioning for Portable Breath Analyzers

et al. 2012

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Various innovative chemical sensors have been developed in recent years to sense dangerous substances in air and trace biomarkers in breath. However, in order to solve real world problems, the sensors must be equipped with efficient sample conditioning that can, e.g., control the humidity, which is much less discussed in literatures. To meet the demand, a miniaturized mouthpiece was developed for personal breath analyzers. A key function of the mouthpiece is to condition the humidity in real breath samples without changing the analyte concentrations and introducing substantial backpressure, which is achieved with optimized packing of desiccant particles. Numerical simulations were carried out to determine the performance of the mouthpiece in terms of various controllable parameters, such as the size, density and geometry of the packing. Mouthpieces with different configurations were built and tested, and the experimental data validated the simulation findings. A mouthpiece with optimized performance reducing relative humidity from 95% (27,000 ppmV) to 29% (8000 ppmV) whereas retaining 92% nitric oxide (50ppbV to 46ppbV) was built and integrated into a handheld exhaled nitric oxide sensor, and the performance of exhaled nitric oxide measurement was in good agreement with the gold standard chemiluminescence technique. Acetone, carbon dioxide, nitric oxide, oxygen and ammonia samples were also measured after passing through the desiccant mouthpiece using commercial sensors to examine wide applicability of this breath conditioning approach.

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“…where k (= 3.145 kJnm 3 mol -1 for CO 2 ) is a constant (Debelak and Schrodt 1979) and U is the gamma function. T c Kamiuto, 2001Reid, 1977Dubinin, 1960Reid, 1977Kamiuto, 2001 Fig. 3 Suggested saturation pressure for CO 2 at below and above its critical temperature 3 Results and discussion…”

Section: Calculation Of Average Pore Size Of Coals From Co 2 Adsorption Isothermmentioning

confidence: 99%

Dynamic nature of supercritical CO2 adsorption on coals

Ozdemir

2016

Adsorption

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Adsorption on non-rigid solids was shown to be a dynamic process. Excess adsorption and desorption isotherms of CO 2 on eight Argonne Premium coal samples were measured at 55°C and pressures up to 14 MPa by manometric method. The excess adsorption isotherms of CO 2 on powdered coals showed almost Langmuir-like to rectilinear shape behavior at low pressures up to 9 MPa, and it increased noticeably at pressures higher than 9 MPa. There was a significant hysteresis between the excess adsorption and desorption isotherms for each rank of coals, which was related to the volumetric uncertainties occurring during the adsorption isotherm measurements. The parameters related to the adsorption capacity and micro porous characteristics of the coal were obtained at different pressure ranges by fitting the experimental data to the modified Dubinin-Astakhov (D-A) equation at the increasingly larger pressure ranges, using only the first 4 data points of the excess adsorption isotherm initially, and progressively using additional data points for the subsequent values. It was shown that the curve fit parameters vary with pressure, and therefore, concluded that the adsorption on non-rigid solids such as CO 2 on coal is indeed a dynamic process. It was suggested that new adsorption isotherm equations need to be developed considering the dynamic nature of the adsorption on solid adsorbents.

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CO2 adsorption equilibria of the honeycomb zeolite beds

Cited by 6 publications

References 2 publications

CO₂ Adsorption over Si-MCM-41 Materials Having Basic Sites Created by Postmodification with La₂O₃

CO₂ Adsorption over Si-MCM-41 Materials Having Basic Sites Created by Postmodification with La₂O₃

Online Sample Conditioning for Portable Breath Analyzers

Dynamic nature of supercritical CO2 adsorption on coals

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CO2 adsorption equilibria of the honeycomb zeolite beds

Cited by 6 publications

References 2 publications

CO2 Adsorption over Si-MCM-41 Materials Having Basic Sites Created by Postmodification with La2O3

CO2 Adsorption over Si-MCM-41 Materials Having Basic Sites Created by Postmodification with La2O3

Online Sample Conditioning for Portable Breath Analyzers

Dynamic nature of supercritical CO2 adsorption on coals

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Product

Resources

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CO₂ Adsorption over Si-MCM-41 Materials Having Basic Sites Created by Postmodification with La₂O₃

CO₂ Adsorption over Si-MCM-41 Materials Having Basic Sites Created by Postmodification with La₂O₃