Sample records for TERMOADSORCION (heat of adsorption)
from WorldWideScience.org

Sample records 1 - 7 shown.



1

Simulación y Análisis de la Operación de Sistemas de Acondicionamiento de Aire por Adsorción/ Analysis and Simulation of the Operation of an Adsorption Air Conditioning System

Builes, D.; Chejne, F.
2004-01-01

Resumen en español En este trabajo se efectúa un análisis termodinámico de la operación de un sistema de acondicionamiento de aire, basado en el uso de una rueda deshumidificadora, una rueda de calor, un calentador de aire y humidificadores adiabáticos. El análisis se basó en un modelo macroscópico de balances de materia y energía, teniendo en cuenta las relaciones de equilibrio de adsorción aplicadas a la sorción de vapor de agua en sílica gel. El modelo permitió simular las c (mas) ondiciones de operación, y determinar la variación del coeficiente de desempeño, con respecto al incremento de temperatura requerido en el calentador de aire para la regeneración del desecante. Se determinó que el coeficiente de desempeño disminuye cuando la temperatura para la regeneración aumenta. Además, es posible obtener las condiciones de confort tan sólo variando la velocidad angular de la rueda, y la alimentación de agua en un humidificador, manteniendo un fácil control del sistema Resumen en inglés In this study a thermodynamic analysis is made of the operation of an air conditioning system based on the use of a dehumidifying wheel, a heat wheel, an air heater, and adiabatic humidifiers. The analysis was based on a macroscopic model of material and energy balances, taking into account the adsorption equilibrium relationships applied to the sorption of water vapor in silica gel. The model allowed to simulate the operating conditions and to determine the variation of (mas) the coefficient of performance with regard to the required temperature increment in the air heater for desiccant regeneration. It was determined that the coefficient of performance decreases when regeneration temperature increases. Furthermore, it is possible to obtain comfort conditions by varying only the angular speed of the wheel and the water feed to a humidifier, thus maintaining easy control of the system

Scientific Electronic Library Online (Spanish)

2

Preparación y caracterización de la zeolita MCM-22 y de su precursor laminar/ Preparation and characterization of MCM-22 zeolite and its layered precursor

Pergher, Sibele B. C.; Corma, Avelino; Fornés, Vicente
2003-12-01

Resumen en inglés The layered precursor of MCM-22 was prepared with different Si/Al ratios: 15, 25, 50, 100 and ¥. Upon heat treatment these precursors form MCM-22 zeolite. Both layered precursor and MCM-22 zeolite were characterized by several techniques: Chemical Analysis by Atomic Absorption Spectroscopy (AAS), X-Ray Diffraction (XRD), Thermo-gravimetric Analysis (TGA), Pore Analysis by N2 and Ar adsorption, Scanning Electron Microscopy (SEM), Infrared Spectroscopy (IR) and Temperature Programmed Desorption of ammonium (TPD).

Scientific Electronic Library Online (Spanish)

3

New acrylic monolithic carbon molecular sieves for O2/N2 and CO2/CH4 separations

Valente Nabais, J. M.; Carrott, P. J. M.; Ribeiro Carrott, M. M. L.; Padre-Eterno, A. M.; Menéndez Díaz, José Ángel

8 pages, 5 figures, 4 tables.-- Available online Dec 20, 2005. | The modification of activated carbon fibres prepared from a commercial textile acrylic fibre into materials with monolithic shape using phenolic resin as binder was studied. The molecular sieving properties for the gas separations CO2/...

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4

Importance of the Hydrophobic Character of Activated Carbons on the Removal of Naphthalene from the Aqueous Phase

Ovín Ania, M.ª Concepción; Cabal Álvarez, Belén; Parra Soto, José Bernardo; Pis Martínez, José Juan

13 pages. | A commercial activated carbon was systematically modified by heat treatment at 450°C and 850°C to obtain a series of carbons with various oxygen contents, porous structures and surface functionalities. The carbons were used to investigate the role of adsorbent properties on the removal o...

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5

Hydrogen adsorption studies on single wall carbon nanotubes

Ansón Casaos, Alejandro; Callejas, M. Alicia; Benito, A. M.; Maser, Wolfgang K.; Izquierdo Pantoja, María Teresa

6 pages, 4 figures.-- Issue title: Carbon '03 Conference (Oviedo, Spain, Jul 6-10, 2003). | Hydrogen adsorption data on as-grown and heat-treated single walled carbon nanotubes (SWNTs) obtained by a volumetric procedure using a Quantachrome Autosorb-1 equipment are presented. The amounts of hydrogen...

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6

Adsorción física sobre sólidos: aspectos termodinámicos/ Physical adsorption on solids: thermodynamic aspects

Arias, Juan Miguel; Paternina, Elihu; Barragán, Daniel
2009-01-01

Resumen en inglés A thermodynamic formalism based on the Gibbs Dividing Surface (GDS) for the description of a solid-fluid interface is presented, so that the adsorption layer is understand as a phase and the adsorption process as the transference of components between a 3-dimensional phase and a 2-dimensional one. Using a state equation derived from the Henry's Law, we shall show how the Langmuir isotherm is deduced from de Gibbs isotherm. The GDS is useful also for understanding the release of heat by a system as the adsorption occurs.

Scientific Electronic Library Online (Spanish)

7

ADSORCIÓN DE RESORCINOL DESDE SOLUCIÓN ACUOSA SOBRE CARBÓN ACTIVADO. RELACIÓN ISOTERMAS DE ADSORCIÓN Y ENTALPÍA DE INMERSIÓN RESORCINOL/ ADSORPTION FROM AQUEOUS SOLUTION ON ACTIVATED CARBON. RELATION ADSORPTION ISOTHERM AND IMMERSION ENTHALPY/ ADSORÇÃO DE RESORCINOL DESDE SOLUÇÃO ACUOSA SOBRE CARVÃO ATIVADO. RELAÇÃO ISOTERMAS DE ADSORÇÃO E ENTALPÍA DE IMERSÃO

Blanco, Diego A; Giraldo, Liliana; JuanC, Moreno
2008-08-01

Resumen en portugués Se estuda a adsorção de resorcinol, sobre carvões ativados modificados, obtidos a partir de um carvão ativado comercial CarbochemTM–PS30, carvão ativado granula (CAG), por meio de tratamento químico com HNO3 7M, carvão ativado enferrujado (CAO), e tratamento térmico sob fluxo de H2, carvão ativado reduzido (CAR); analisa-se a influência do pH da solução, a redução e oxidação da superfície do carvão e se determina a entalpía de imersão dos carvõe (mas) s ativados em soluções acuosas de resorcinol. A interação sólido- solução se caracteriza pela análise das isotermas de adsorção a 298 K aos pHs de 7, 9 e 11 com o propósito de avaliar o sistema sobre e por embaixo do valor das pKa do resorcinol. A capacidade de adsorção dos carvões aumenta ao diminuir o pH da solução. A quantidade retida aumenta no carvão reduzido ao pH de máxima adsorção e diminui no carvão enferrujado. Os resultados experimentais das isotermas de adsorção se ajustaram aos modelos de Freundlich e Langmuir, obtendo valores para o parâmetro Qmáx do modelo de Langmuir noCAGde 179, 156 e 44mgg-1, para valores de pHde 7, 9 e 11 respectivamente. No caso dos carvões modificados se obtêm valores de 233, 179 e 164 mgg-1, para o CAR, CAG e CAO a pH 7 respectivamente. Como tendência geral a adsorção do resorcinol aumenta no seguinte ordem CAR > CAG > CAO. Similares conclusões se obtêm das entalpías de imersão, cujos valores se incrementam com a quantidade de soluto retido. No caso do CAG se obtêm entalpías de imersão entre 25,8 a 40,9 Jg-1 para soluções acuosas de resorcinol numa casta de 20 a 1500 mgL-1. Resumen en español Se estudia la adsorción de resorcinol sobre carbones activados modificados, obtenidos a partir de un carbón activado granular comercial CarbochemTM –PS30, (CAG), por medio de tratamiento químico con HNO37M, carbón activado oxidado (CAO) y tratamiento térmico bajo flujo de H2, carbón activado reducido (CAR). Se analiza la influencia del pH de la solución, la reducción y oxidación de la superficie del carbón y se determina la entalpía de inmersión de los c (mas) arbones activados en soluciones acuosas de resorcinol. La interacción sólido-solución se caracteriza por el análisis de las isotermas de adsorción a 298 K a los pHde 7, 9 y 11 con el propósito de evaluar el sistema sobre y por debajo del valor de las pKa del resorcinol. La capacidad de adsorción de los carbones aumenta al disminuir el pH de la solución. La cantidad retenida aumenta en el carbón reducido al pH de máxima adsorción y disminuye en el carbón oxidado. Los resultados experimentales de las isotermas de adsorción se ajustaron a los modelos de Freundlich y Langmuir, obteniendo valores para el parámetro Qmáx del modelo de Langmuir en el CAG de 179, 156 y 44 mgg-1, para valores de pH de 7, 9 y 11, respectivamente. En el caso de los carbones modificados se obtienen valores de 233, 179 y 164 mgg-1, para el CAR, CAG y CAO a pH 7, respectivamente. Como tendencia general la adsorción de resorcinol aumenta en el siguiente orden CAR > CAG > CAO. Similares conclusiones se obtienen de las entalpías de inmersión, cuyos valores se incrementan con la cantidad de soluto retenido. En el caso del CAG se obtienen entalpías de inmersión entre 25,8 a 40,9 Jg-1 para soluciones acuosas de resorcinol en un rango de 20 a 1500 mgL-1. Resumen en inglés The resorcinol adsorption on a modified activated carbon, obtained from an activated commercial carbon CarbochemTM- PS30, CAG, modified by means of chemical treatment with HNO3 7M, oxidized activated carbon (CAO) and heat treatment under H2 flow, reduced activated carbon (CAR), are studied. The influence of solution pH, the reduction and oxidation of the activated surface carbon are analyzed, and the immersion enthalpy of activated carbons in resorcinol aqueous solutions (mas) is determined. The interaction solid-solution is characterized by adsorption isotherms analysis, at 298 K and at pHs of 7, 9 and 11 in order to evaluate the system on and below the value of resorcinol pKa. The adsorption capacity of carbons increases whit diminishing solution pH. The amount retained increases in the reduced carbon at maximum adsorption pH and diminishes in the oxidized carbon. The experimental results of the adsorption isotherms are adjusted to the Freundlich and Langmuir models, obtaining values for the Qmax parameter Langmuir’s model in the CAG of 179, 156 and 44 mgg-1, for pH values of 7, 9 and 11 respectively. In the case of modified carbons values of 233, 179 and 164 mgg-1 are obtained for the CAR, CAG and CAO to pH 7 respectively. As general tendency the resorcinol adsorption increases in the following order CAR > CAG > CAO. Similar conclusions from immersion enthalpies are obtained, their values increase with the amount of solute retained. In the case of the CAG, immersion enthalpies between 25.8 to 40.9 Jg-1 are obtained for resorcinol aqueous solutions in a range from 20 to 1500 mgL-1.

Scientific Electronic Library Online (Spanish)