Abstract
Concurrent equilibrium adsorption on a highly porous activated carbon of both water vapour and toluene was studied to determine the extent and the location of toluene adsorption in the presence of water. We report small angle neutron scattering (SANS) measurements in which the H/D ratio of both the water and toluene components is varied. Measurements are made both in the lower transfer wave vector region (5 × 10−2 ≤ q ≤ 1 Å−1) and in the high q region >1 Å−1. Just below the Porod scattering region (0.3–1 Å−1), the liquid/vapour interface contributes significantly. To solve the intrinsic ternary character of the signal in this region, contrast variation measurements with H2O/D2O mixtures alone and with toluene-D and toluene-H mixtures alone at constant relative pressure were performed. The carbon samples, of commercial origin (Norit R1), were previously treated with nitric acid to reduce the ash content, which simplifies the data treatment in the diffraction region at high q.
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Abbreviations
- AC:
-
Activated carbon
- RH:
-
Relative humidity
- RP:
-
Relative pressure
- SWNT:
-
Single wall nanotube
- GCMC:
-
Grand canonical Monte Carlo calculation
- SAXS:
-
Small angle X-ray scattering
- SANS:
-
Small angle neutron scattering
- WAXS:
-
Wide angle X-ray scattering
- TH:
-
Hydrogenated toluene C7H8
- TD:
-
Deuterated toluene C7D8
- THD:
-
50:50 v/v mixture of toluene H and toluene D
- ILL:
-
Institut Laue Langevin
- b a :
-
Scattering length of the adsorbate
- b C :
-
Scattering length of carbon
- b D :
-
Scattering length of deuterium
- b H :
-
Scattering length of hydrogen
- d a :
-
Mass density of the adsorbate
- d C :
-
Mass density of carbon
- I :
-
Intensity of neutrons
- I inc :
-
Intensity from incoherent scattering
- M a :
-
Molecular weight of the adsorbate
- M C :
-
Molecular weight of carbon
- q :
-
Transfer wave vector
- S(q) :
-
Structure factor
- S BET :
-
Specific surface area
- λ :
-
Wavelength of the incident neutron beam
- ρ a :
-
Scattering length density of the adsorbate
- ρ C :
-
Scattering length density of the carbon
- θ :
-
Scattering angle
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Acknowledgments
We are grateful to the Institut Laue-Langevin, Grenoble for access to the D16 instrument, and to Norit for providing the carbon samples. We express our gratitude to Bruno Demé, György Bosznai and Orsolya Czakkel for their technical assistance. This research was supported by the EU – Hungarian Government joint fund (GVOP – 3.2.2 – 2004 – 07 – 0006/3.0).
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László, K., Geissler, E. (2011). The Competitive Role of Water in Sorption Processes on Porous Carbon Surfaces. In: Mikhalovsky, S., Khajibaev, A. (eds) Biodefence. NATO Science for Peace and Security Series A: Chemistry and Biology. Springer, Dordrecht. https://doi.org/10.1007/978-94-007-0217-2_6
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DOI: https://doi.org/10.1007/978-94-007-0217-2_6
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