Pore Size Distribution of Carbon with Different Probe Molecules

Wongkoblap, Atichat; Intomya, Worapot; Somrup, Warangkhana; Charoensuk, Sorod; Junpirom, Supunnee; Tangsathitkulchai, Chaiyot

doi:10.4186/ej.2010.14.3.45

Cited by 12 publications

(9 citation statements)

References 13 publications

(23 reference statements)

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“…To this end, there is a trend in recent years to model pores of finite length [10][11][12] as the desorption branch of a simulated isotherm agrees better with experimental data. We adopted the same approach in this paper, and in addition to the consideration of finite length we also considered functional groups as it is known that they have an important role in the adsorption and desorption of associating fluids, such as water [13].…”

Section: Introductionmentioning

confidence: 59%

Characterization of Single Wall Carbon Nanotubes and Activated Carbon with Water Adsorption in Finite-Length Pore Models

Wongkoblap¹,

Tangsathitkulchai²,

Klomkliang³

et al. 2013

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Abstract. Grand Canonical Monte Carlo simulation is used to study water adsorption in activated carbon (AC) and carbon nanotubes (CNT) which is modelled as a bundle of seven tubes, and the simulation results are compared with the experimental data. To investigate the role of functional groups on water adsorption, hydroxyl groups are grafted at various locations on the surface of AC and CNT. For carbon nanotubes, the spacing between tubes can affect the isotherm. For small spacing and functional groups are located on the exterior surface of the central tube, the isotherm is not affected by the spacing and the concentration of the functional group. This is simply due to the geometrical constraint that prevents water to adsorb in the interstices between the tubes. However, the onset of adsorption occurs at lower pressures when the functional group is positioned in the larger interstices. When the spacing is larger, water clusters are readily formed around the functional group, resulting in an enhancement in adsorption, and pore-filling occurs in the interstices. For AC which is modelled as slit pores, the position and amount of functional group affect adsorption. The effects of temperature were also studied, and we observed an unusual behaviour in that the adsorptive capacity at 10 °C is lower than that at 15 °C which is confirmed with our computer simulation.

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Section: Introductionmentioning

confidence: 59%

Characterization of Single Wall Carbon Nanotubes and Activated Carbon with Water Adsorption in Finite-Length Pore Models

Wongkoblap¹,

Tangsathitkulchai²,

Klomkliang³

et al. 2013

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“…Adsorption isotherms of CH4 and CO2 in bun sizes are shown in Figure 13a,b, respectively; the sim est tubes (10.8 Å ) and those of larger tubes (16.3 Å fluid molecules are initially adsorbed in the interior cause of the stronger solid-fluid potential inside th for CO2 adsorption and Figure 15a-c for CH4 adsorp can be observed in the case of using GCMC simulation; however, they are not found for PSD obtained from the DFT calculation [46]. Although the simulation isotherm obtained for finite-length slit pore model proposed in this study cannot present the entire structure range of porous carbon, indeed some important characteristics are revealed.…”

Section: Effects Of Tube Diameter On Adsorption Isothmentioning

confidence: 93%

Monte Carlo Simulation and Experimental Studies of CO2, CH4 and Their Mixture Capture in Porous Carbons

et al. 2021

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Adsorption of carbon dioxide and methane in porous activated carbon and carbon nanotube was studied experimentally and by Grand Canonical Monte Carlo (GCMC) simulation. A gravimetric analyzer was used to obtain the experimental data, while in the simulation we used graphitic slit pores of various pore size to model activated carbon and a bundle of graphitic cylinders arranged hexagonally to model carbon nanotube. Carbon dioxide was modeled as a 3-center-Lennard-Jones (LJ) molecule with three fixed partial charges, while methane was modeled as a single LJ molecule. We have shown that the behavior of adsorption for both activated carbon and carbon nanotube is sensitive to pore width and the crossing of isotherms is observed because of the molecular packing, which favors commensurate packing for some pore sizes. Using the adsorption data of pure methane or carbon dioxide on activated carbon, we derived its pore size distribution (PSD), which was found to be in good agreement with the PSD obtained from the analysis of nitrogen adsorption data at 77 K. This derived PSD was used to describe isotherms at other temperatures as well as isotherms of mixture of carbon dioxide and methane in activated carbon and carbon nanotube at 273 and 300 K. Good agreement between the computed and experimental isotherm data was observed, thus justifying the use of a simple adsorption model.

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“…The adsorption of methane increases with pressures and the continuous pore filling of monolayer can be observed. The capillary condensation cannot be observed, this is due to that CH4 behaves as supercritical fluid at 298 K. When pore width increases, the adsorption isotherm decreases, due to the less interaction between solid and methane in the case of larger width [12][13][14]. It is noted that the number of adsorbed molecules in the larger pore increases with pore width, although the pore density is decreased.…”

Section: Adsorption Isothermsmentioning

confidence: 96%

Computer Simulation Study for Functional Group Effect on Methane Adsorption in Porous Silica Glass

Teerachawanwong¹,

Makkaroon²,

Boonfung³

et al. 2019

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In this paper, adsorption of methane on porous silica glass was investigated to see whether functional groups can affect the adsorption behavior. Adsorption isotherms for pores having widths between 7 and 40Å at 283 and 298 K were investigated using a Monte Carlo simulation (MC) method. The model of porous silica glass proposed in this study was assumed to be a finite-length slit pore which consisted of two parallel walls. The tetrahedral structure of SiO4 was used as atomic structure for the wall surface. Hydroxyl was assumed as the surface functional group which allocated either at pore mouth or random with concentration of 5 and 10%. It was found that the concentration of functional group has less significant effect on the adsorption of methane. The adsorption isotherm decreased a bit with an increase of functional group concentration. Effects of functional group position on adsorption isotherm were also investigated, the adsorption isotherm obtained for the random topology was greater than that for the pore mouth topology, due to the pore blocking effects. At the same pore width, the adsorption isotherm at 283K was greater than that at 293K, and this was due to that the adsorption of methane on porous silica glass was a physical adsorption. The initial adsorption of methane shifted to the higher pressure by increasing pore width, and the maximum adsorption capacity decreased with an increase of pore size, because of the pore packing effect.

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Pore Size Distribution of Carbon with Different Probe Molecules

Cited by 12 publications

References 13 publications

Characterization of Single Wall Carbon Nanotubes and Activated Carbon with Water Adsorption in Finite-Length Pore Models

Characterization of Single Wall Carbon Nanotubes and Activated Carbon with Water Adsorption in Finite-Length Pore Models

Monte Carlo Simulation and Experimental Studies of CO2, CH4 and Their Mixture Capture in Porous Carbons

Computer Simulation Study for Functional Group Effect on Methane Adsorption in Porous Silica Glass

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