Use of nitrogen vs. carbon dioxide in the characterization of activated carbons

Garrido, Julián; Linares‐Solano, A.; Martı́n-Martı́nez, José Miguel; Molina‐Sabio, M.; Rodriguez-Reinoso, F.; Torregrosa, R.

doi:10.1021/la00073a013

Cited by 464 publications

(246 citation statements)

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“…This difference in isotherm uptake is attributed to activated diffusion effects for N 2 in ultramicroporosity at -196°C, which is not apparent for CO 2 adsorption at -78°C. 50 Table S5). Steep uptake of nitrogen isotherms of Hadessen shales and kerogens at -196°C at very low p/p 0 (p/p 0 < 0.02) indicates filling of ultramicropores.…”

Section: Sorption Pore Volumesmentioning

confidence: 99%

“…50,53,54 Carbon dioxide isotherms at 0°C of shale and kerogen are Type I Isotherms (see Supporting Information Table S3 for tabulated data). At these temperature and pressure conditions (< 0.1 MPa), CO 2 sorption is limited to ultramicropores (< ~0.7 nm).…”

Section: Micropore Volumesmentioning

confidence: 99%

“…56 A value of 1.023 g cm -3 was used previously in a detailed study of the adsorption of CO 2 on activated carbons. 50 Additionally, a non-local density functional theory (NLDFT) equilibrium model with a kernel based on slit-shaped pores in carbon was used to calculate pore size distributions (see Supporting Information, Section G, Figures S7 and S8) and micropore volumes from the isotherms. These pore size distributions (< 5 nm) are shifted to slightly lower pore sizes compared with Eagle Ford shale obtained from nitrogen (-196°C).…”

Section: Micropore Volumesmentioning

confidence: 99%

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High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

et al. 2014

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. (2014) 'High-pressure methane adsorption and characterization of pores in Posidonia shales and isolated kerogens.', Energy fuels., 28 (5). pp. 2886-2901. Further information on publisher's website:http://dx.doi.org/10.1021/ef402466mPublisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Energy Fuels, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://dx.doi.org/10.1021/ef402466m. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractSorption capacities and pore characteristics of bulk shales and isolated kerogens have been determined for immature, oil-window and gas-window mature samples from the Lower Toarcian Posidonia Shale formation. Dubinin-Radushkevich (DR) micropore volumes, sorption pore volumes and surface areas of shales and kerogens were determined from CO 2 adsorption isotherms at -78°C and 0°C, and N 2 adsorption isotherms at -196°C. Mercury injection capillary pressure porosimetry, grain density measurements and helium pycnometry were used to determine shale and kerogen densities and total pore volumes.Total porosities decrease through the oil-window and then increase into the gas-window.High-pressure methane isotherms up to 14 MPa were determined at 45, 65 and 85°C on dry shale and at 45 and 65°C on kerogen. Methane excess uptakes at 65°C and 11.5 MPa were in the range 0.056-0.110 mmol g -1 (40-78 scf t -1 ) for dry Posidonia shales and 0.36-0.70 mmol g -1 (253-499 scf t -1 ) for the corresponding dry kerogens. Absolute methane isotherms were calculated by correcting for the gas at bulk gas phase density in the sorption pore volume. The enthalpies of CH 4 adsorption for shales and kerogens at zero surface coverage showed no significant variation with maturity, indicating that the sorption pore volume is the primary control on sorption uptake. The sum of pore volumes measured by a) CO 2 sorption at -78°C and b) mercury injection, are similar to the total porosity for shales. Since mercury in our experiments occupies pores with constrictions larger than ca. 6 nm, we infer that porosity measured by CO 2 adsorption at -78°C in the samples used in this study is largely within pores with effective diameters smaller than 6 nm. The linear correlation between maximum CH 4 surface excess sorption and CO 2 sorption pore volume at -78°C is very strong for both shales and kerogens, and goes through the origin, suggestin...

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Section: Sorption Pore Volumesmentioning

confidence: 99%

Section: Micropore Volumesmentioning

confidence: 99%

Section: Micropore Volumesmentioning

confidence: 99%

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High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

et al. 2014

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“…Adsorption analysis at atmospheric pressure using a slightly smaller molecule compared to N 2 as CO 2 (0.36 nm vs. 0.33 nm) and a higher adsorption temperature (0ºC vs. -196ºC) has been proposed by some of us for the characterization of the narrow microporosity in porous solids (pores below 0.7 nm) [29,30]. Furthermore, CO 2 adsorption can be used to evaluate the presence of narrow constrictions usually inaccessible to N 2 at cryogenic temperatures [31].…”

Section: Co 2 Adsorption Analysis At Atmospheric and High Pressurementioning

confidence: 99%

High selectivity of TiC-CDC for CO2/N2 separation

Silvestre-Albero

Rico-Francés

Rodríguez‐Reinoso

et al. 2013

Carbon

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A series of carbide-derived carbons (CDC) have been prepared starting from TiC and using different chlorine treatment temperatures (500ºC-1200ºC). Contrary to N 2 adsorption measurements at -196ºC, CO 2 adsorption measurements at room temperature and high pressure (up to 1 MPa) together with immersion calorimetry measurements into dichloromethane suggest that the synthesized CDC exhibit a similar porous structure, in terms of narrow pore volume, independently of the temperature of the reactive extraction treatment used (samples synthesized below 1000ºC). Apparently, these carbide-derived carbons exhibit narrow constrictions were CO 2 adsorption under standard conditions (0ºC and atmospheric pressure) is kinetically restricted. The same accounts for a slightly larger molecule as N 2 at a lower adsorption temperature (-196ºC), i.e. textural parameters obtained from N 2 adsorption measurements on CDC 2 must be underestimated. Furthermore, here we show experimentally that nitrogen exhibits an unusual behavior, poor affinity, on these carbide-derived carbons. CH 4 with a slightly larger diameter (0.39 nm) is able to partially access the inner porous structure whereas N 2 , with a slightly smaller diameter (0.36 nm), does not. Consequently, these CDC can be envisaged as excellent sorbent for selective CO 2 capture in flue-gas streams.

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“…There remains some controversy in the literature regarding the phase of the sorbed CO 2 , especially as regards the density of the sorbed layer. This manifests itself in an enormous range of values being reported for its sorption cross-section [Garrido et al, 1987]. Meanwhile, the very high value of saturation pressure, taken together with the operating limits of the available device (760 torr maximum pressure) suggests that CO 2 will only be useful for exploring microporosity.…”

Section: Experimental Methods Task 51 Fundamentals Of Ammonia Adsorpmentioning

confidence: 99%

NOx Control Options and Integration for US Coal Fired Boilers

Bockelie¹,

Davis²,

Linjewile³

et al. 2003

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This is the fourteenth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NO x control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. Using the initial CFD baseline modeling of the Gavin Station and the plant corrosion maps, six boiler locations for the corrosion probes were identified and access ports have been installed. Preliminary corrosion data obtained appear consistent and believable.In situ, spectroscopic experiments at BYU reported in part last quarter were completed. New reactor tubes have been made for BYU's CCR that allow for testing smaller amounts of catalyst and thus increasing space velocity; monolith catalysts have been cut and a small reactor that can accommodate these pieces for testing is in its final stages of construction. A poisoning study on Ca-poisoned catalysts was begun this quarter. A possible site for a biomass co-firing test of the slipstream reactor was visited this quarter. The slipstream reactor at Rockport required repair and refurbishment, and will be re-started in the next quarter. This report describes the final results of an experimental project at Brown University on the fundamentals of ammonia / fly ash interactions with relevance to the operation of advanced NO x control technologies such as selective catalytic reduction. The Brown task focused on the measurement of ammonia adsorption isotherms on commercial fly ash samples subjected to a variety of treatments and on the chemistry of dry and semi-dry ammonia removal processes.iii Table of Our program contains five major technical tasks:• evaluation of Rich Reagent Injection (RRI) for in-furnace NO x control;• demonstration of RRI technologies in full-scale field tests at utility boilers;• impacts of combustion modifications (including corrosion and soot);• ammonia adsorption / removal from fly ash; and • SCR catalyst testing.To date, good progress is being made on the overall program. We have seen considerable interest from industry in the program due to our successful initial field tests of the RRI technology and the corrosion monitor.During the last three months, our accomplishments include the following:• Using the initial CFD baseline modeling of the Gavin Station and the plant corrosion maps, six boiler locations for the corrosion probes were identified and access ports have been installed.• One probe has been collecting data for more than three months and two others have been in service for more than two months; preliminary corrosion data obtained appear consistent and believable.• In situ, spectroscopic experiments at BYU reported in part last quarter were completed; the most significant finding of these investigations was a consistent indication that vanadium does not sulfate during SCR reaction in the presence of gas-phase SO 2 whil...

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Use of nitrogen vs. carbon dioxide in the characterization of activated carbons

Cited by 464 publications

References 1 publication

High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

High selectivity of TiC-CDC for CO2/N2 separation

NOx Control Options and Integration for US Coal Fired Boilers

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