Fiber optic sensors based on hybrid phenyl-silica xerogel films to detect n-hexane: determination of the isosteric enthalpy of adsorption
Fecha
2017Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión publicada / Argitaratu den bertsioa
Impacto
|
10.3762/bjnano.8.51
Resumen
We investigated the response of three fiber optic sensing elements prepared at pH 10 from phenyltriethoxysilane (PhTEOS) and
tetraethylsilane (TEOS) mixtures with 30, 40, and 50% PhTEOS in the silicon precursor mixture. The sensing elements are referred
to as Ph30, Ph40 and Ph50, respectively. The films were synthesized by the sol–gel method and affixed to the end of optical fibers
by the dip- ...
[++]
We investigated the response of three fiber optic sensing elements prepared at pH 10 from phenyltriethoxysilane (PhTEOS) and
tetraethylsilane (TEOS) mixtures with 30, 40, and 50% PhTEOS in the silicon precursor mixture. The sensing elements are referred
to as Ph30, Ph40 and Ph50, respectively. The films were synthesized by the sol–gel method and affixed to the end of optical fibers
by the dip-coating technique. Fourier transform infrared spectroscopy, N2 adsorption–desorption at 77 K and X-ray diffraction analysis
were used to characterize the xerogels. At a given pressure of n-hexane, the response of each sensing element decreased with
temperature, indicating an exothermic process that confirmed the role of adsorption in the overall performance of the sensing elements.
The isosteric adsorption enthalpies were obtained from the calibration curves at different temperatures. The magnitude of the
isosteric enthalpy of n-hexane increased with the relative response and reached a plateau that stabilized at approximately
−31 kJ mol−1 for Ph40 and Ph50 and at approximately −37 kJ mol−1 for Ph30. This indicates that the adsorbate–adsorbent interaction
was dominant at lower relative pressure and condensation of the adsorbate on the mesopores was dominant at higher relative
pressure. [--]
Materias
Fiber optic sensors,
Isosteric enthalpy of adsorption,
n-hexane,
Phenyl-silica,
Xerogel films
Editor
Beilstein-Institut
Publicado en
Beilstein Journal of Nanotechnology
Departamento
Universidad Pública de Navarra. Departamento de Química Aplicada /
Nafarroako Unibertsitate Publikoa. Kimika Aplikatua Saila /
Universidad Pública de Navarra/Nafarroako Unibertsitate Publikoa. Institute for Advanced Materials and Mathematics - INAMAT2
Versión del editor
Entidades Financiadoras
This work was supported by the Ministerio de Ciencia e Innovación (CTQ2009-07993). Paula Moriones is thankful to the Departamento de Industria y Tecnología, Comercio y Trabajo of the Navarre Government for fellowships (Ref. number 269/01/08).
Aparece en las colecciones
Los documentos de Academica-e están protegidos por derechos de autor con todos los derechos reservados, a no ser que se indique lo contrario.
La licencia del ítem se describe como © 2017 Echeverría et al.; licensee Beilstein-Institut. This is an Open Access article under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The license is subject to the Beilstein Journal of Nanotechnology terms and conditions: (http://www.beilstein-journals.org/bjnano)