Norcross, GA, United States
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Balzer C.,Bavarian Center for Applied Energy Research | Wildhage T.,Bavarian Center for Applied Energy Research | Braxmeier S.,Bavarian Center for Applied Energy Research | Reichenauer G.,Bavarian Center for Applied Energy Research | Olivier J.P.,Micromeritics Instrument Co.
Langmuir | Year: 2011

N2 and CO2 sorption measurements with in situ dilatometry implemented in a commercial volumetric sorption instrument were performed at 77 and 273 K, respectively. The resolution of the linear deformation was about ±0.2 μm. To separate effects due to microporosity, external surface area and mesopores synthetic porous carbons (xerogels) with different external surface areas and microporosities were applied as a model system. The experimental data show that the relative length change of the monolithic carbon xerogels investigated passes different stages during ad- and desorption, which are connected to micropore-, multilayer- and mesopore-sorption. The length change observed in the range of micropore and surface adsorption was found to be nonmonotonic and to take negative as well as positive values, with the maximum swelling observed being on the order of 4°. With respect to the length change, the micropore structure seems to have the most significant impact on the overall length change, while the external surface is only of minor importance. Quantiative analysis of the deformation according to the models of Bangham and Scherer for the length change in the range of multilayer- and mesopore-adsorption allows extracting the macrosopic as well as the skeletal Young's modulus. © 2011 American Chemical Society.

Seredych M.,City College of New York | Jagiello J.,Micromeritics Instrument Co. | Bandosz T.J.,City College of New York
Carbon | Year: 2014

Nanoporous S-doped carbon and its composites with graphite oxide were tested as adsorbents of CO2 (1 MPa at 0°C) after degassing either at 120 °C or 350 °C. The adsorption capacities were over 4 mmol/g at ambient pressure and 8 mmol/g at 0.9 MPa in spite of a low volume of micropores. The nitrogen adsorption experiments showed an increase in porosity upon an increase in the degassing temperature. The extent of this effect depends on the stability of surface groups. Interestingly, the CO2 adsorption, especially at low pressure, was not affected. The good performance is due to the presence of ultramicropores similar in sizes to CO2 molecule and to sulfur in various functionalities. Sulfur incorporated to aromatic rings enhances CO2 adsorption via acid-base interactions in micropores. Moreover, sulfonic acids, sulfoxides and sulfones attract CO2 via polar interactions. Hydrogen bonding of CO2 with acidic groups on the surface can also play an important role in the CO2 retention. These carbons have high potential for application as CO2 removal media owing to their high degree of pore space utilization. The results obtained also show that high degassing temperatures might result in the decomposition of surface groups and thus in changes in surface interactions. © 2014 Elsevier Ltd. All rights reserved.

Wang H.,Rutgers University | Yao K.,King Abdullah University of Science and Technology | Zhang Z.,Jinan University | Jagiello J.,Micromeritics Instrument Co. | And 3 more authors.
Chemical Science | Year: 2014

In industry, cryogenic rectification for separating xenon from other noble gases such as krypton and argon is an energy and capital intensive process. Here we show that a microporous metal-organic framework, namely Co 3(HCOO)6 is capable of effective capture and separation of xenon from other noble gases. Henry's constant, isosteric heat of adsorption (Qst), and IAST selectivity are calculated based on single component sorption isotherms. Having the highest Qst reported to date, Co 3(HCOO)6 demonstrates high adsorption capacity for xenon and its IAST selectivity for Xe-Kr is the largest among all MOFs investigated to date. To mimic real world conditions, breakthrough experiments are conducted on Xe-Kr binary mixtures at room temperature and 1 atmosphere. The results are consistent with the calculated data. These findings show that Co 3(HCOO)6 is a promising candidate for xenon capture and purification. Our gas adsorption measurements and molecular simulation study also reveal that the adsorption of xenon represents the first example of commensurate adsorption of atomic gases near ambient conditions. © 2014 The Royal Society of Chemistry.

Milina M.,ETH Zurich | Mitchell S.,ETH Zurich | Michels N.-L.,ETH Zurich | Kenvin J.,Micromeritics Instrument Co. | Perez-Ramirez J.,ETH Zurich
Journal of Catalysis | Year: 2013

Adopting a systematic demetallation strategy to prepare hierarchical ZSM-5 zeolites with a wide range of concomitant micro- and mesoporosity, we precisely examine the relation between variations in the porous and acidic properties. A comparative assessment of the type, concentration, and strength of acid sites is attained through the infrared study of adsorbed probe molecules (pyridine, 2,4,6-trimethylpyridine, 2,6-di-tert-butylpyridine, and d3-acetonitrile), the temperature-programmed surface reaction (TPSR) of n-propylamine and the cracking of n-hexane. The impact of these core intrinsic properties on the hierarchical zeolite performance is quantified in liquid-phase reactions with distinct acidity demands and diffusion constraints, including the alkylation of toluene with isopropanol or benzyl alcohol and the esterification of hexanoic acid with benzyl alcohol. Optimal post-synthetic modification greatly improves the initial turnover rates per Brønsted acid site. The relative performance is strongly influenced by both the mesopore surface area and by the associated concentration and strength of acid sites. The need for improved characterization of the mesopore surface acidity is highlighted. © 2013 Elsevier Inc. All rights reserved.

Hauser B.G.,Northwestern University | Farha O.K.,Northwestern University | Exley J.,Micromeritics Instrument Co. | Hupp J.T.,Northwestern University
Chemistry of Materials | Year: 2013

Thermal treatment of highly stable porous organic polymers based upon the Yamamoto polymerization of 2,2′,7,7′-tetrabromo-9,9′- spirobifluorene was done. The polymers are shown to be thermally and chemically stable. Upon thermal treatment the polymers are shown to have BET surface areas of ca. 2,000 m2/g and 2,500 m2/g respectively. © 2012 American Chemical Society.

Jagiello J.,Micromeritics Instrument Co. | Olivier J.P.,Micromeritics Instrument Co.
Adsorption | Year: 2013

In our recent paper (Jagiello and Olivier, Carbon 55:70-80, 2013) we considered introducing energetical heterogeneity (EH) and geometrical corrugation (GC) to the pore walls of the standard carbon slit pore model. We treated these two effects independently and we found that each of them provides significant improvement to the carbon model. The present work is a continuation of the previous one, as we include both effects in one comprehensive model. The existing standard slit pore model widely used for the characterization of activated carbons assumes graphite-like energetically uniform pore walls. As a result of this assumption adsorption isotherms calculated by the non-local density functional theory (NLDFT) do not fit accurately the experimental N 2 data measured for real activated carbons. Assuming a graphene-based structure for activated carbons and using a two-dimensional-NLDFT treatment of the fluid density in the pores we present energetically heterogeneous and geometrically corrugated (EH-GC) surface model for carbon pores. Some parameters of the model were obtained by fitting the model to the reference adsorption data for non-graphitized carbon black. For testing, we applied the new model to the pore size analysis of porous carbons that had given poor results when analyzed using the standard slit pore model. We obtained an excellent fit of the new model to the experimental data and we found that the typical artifacts of the standard model were eliminated. © 2013 Springer Science+Business Media New York.

Xu R.,Micromeritics Instrument Co.
Particuology | Year: 2015

This review covers the progress of light scattering applications in the field of particle characterization in the past decade. The review addresses static light scattering (the measurement of scattering intensities due to light-particle interaction at various spatial locations), dynamic light scattering (the measurement of scattering due to light-particle interaction as a function of time), and scattering tracking analysis (the tracking of particle movement through scattering measurement). © 2014 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Kajdos A.,Georgia Institute of Technology | Kvit A.,University of Wisconsin - Madison | Jones F.,Georgia Institute of Technology | Jagiello J.,Micromeritics Instrument Co. | Yushin G.,Georgia Institute of Technology
Journal of the American Chemical Society | Year: 2010

(Figure Presented) The power density and charge-discharge time of electrical double layer capacitors are largely determined by how fast the electrolyte ions can travel within the carbon electrode particles. Our systematic studies using zeolite-templated carbons show that an enhancement in ion transport rate by more than 2 orders of magnitude is possible by minimizing the micropore tortuosity. Very uniform carbon deposition was achieved using a well-controlled process involving the decomposition of acetylene precursor at a reduced pressure of 10 Torr and under a constant flow rate of 100 sccm. Selected carbon samples with well-aligned, straight micropores demonstrate high specific capacitance of up to 300 F/g and outstanding frequency response of up to 10 Hz for 250 μm thick electrodes, indicating an attractive combination of high specific energy and high specific power in electrical double layer capacitors. Such properties are critical for many peak-power hungry applications, such as the leveling of subsecond disturbances in power lines. Our findings provide guidance for the optimal design of porous carbons with greatly improved power storage characteristics. Copyright © 2010 American Chemical Society.

Zukal A.,J. Heyrovsky Institute of Physical Chemistry | Jagiello J.,Micromeritics Instrument Co. | Mayerova J.,J. Heyrovsky Institute of Physical Chemistry | Cejka J.,J. Heyrovsky Institute of Physical Chemistry
Physical Chemistry Chemical Physics | Year: 2011

Siliceous SBA-15 mesoporous molecular sieves were functionalized with different amounts of 3-aminopropyl-trimethoxysilane. To obtain a more detailed insight into the material properties of the prepared samples, their textural parameters were combined with results of thermal analysis. Adsorption isotherms of carbon dioxide on parent and functionalized SBA-15 were measured in the temperature range from 273 to 333 K. From the temperature dependence of CO 2 isotherms the isosteric adsorption heats of CO2 were determined and discussed. Information about the surface energetic heterogeneity caused by tethered 3-aminopropyl groups were obtained from CO2 adsorption energy distributions calculated using the theoretical CO2 adsorption isotherms derived from the non-local density functional theory. The values of isosteric heats and the energy distributions of CO2 adsorption detect highly energetic sites and enabled quantification of their concentrations. This journal is © the Owner Societies.

Jagiello J.,Micromeritics Instrument Co. | Olivier J.P.,Micromeritics Instrument Co.
Carbon | Year: 2013

In this work, we show that the standard slit pore model widely used for the characterization of activated carbons may be improved by introducing structural and/or energetical heterogeneity to the surface of pore walls. The existing one dimensional slit pore model assumes graphite-like energetically uniform pore walls. As a result of this assumption adsorption isotherms calculated by the non local density functional theory (NLDFT) do not fit accurately the experimental N2 data measured for real activated carbons. Assuming a graphene-based structural framework for activated carbons and using a 2D-NLDFT treatment of the fluid density in the pores we consider two options for model pores: energetically heterogeneous (EH) and geometrically corrugated (GC). For testing, we applied these two models to the pore size analysis of porous carbons that were giving poor results of the analysis with the standard slit model. We found that the typical artifacts of the homogeneous slit pore model were eliminated. Also, the agreement of the new models with experimental data was significantly better than that of the standard slit model. © 2012 Elsevier Ltd. All rights reserved.

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