One-sided single-pellet technique for adsorption and intraparticle diffusion

Doğu, Timur
Dogu, G
McCoy, BJ
Smith, JM
The one-sided single-pellet dynamic technique introduced in this article is shown to be a very effective and simple method for the analysis of adsorption and diffusion in porous solids. Moment expressions are presented for reversible and irreversible adsorption processes. Since the adsorption equilibrium constant is the only unknown parameter in the first moment expression, this parameter can be evaluated from a single set of pulse-response experiments. This technique to evaluate the adsorption equilibrium constant is illustrated using ethylbromide as tracer. It is also shown that for a very strongly adsorbing tracer, such as 1,2-dichloroethane in soil, modified moment expressions derived with a semiinfinite boundary condition are necessary unless a criterion developed in this work is satisfied.


Single pellet reactor for the dynamic analysis of gas-solid reactions ''reaction of SO2 with activated soda''
Kopac, T; Dogu, G; Doğu, Timur (1996-05-01)
Single-pellet moment technique which was initially proposed for the measurement of effective diffusivities in porous catalysts and adsorption rate and equilibrium constants was modified for the analysis of gas-solid reactions. In this technique dynamic version of the Wicke-Kallenbach single-pellet cell was used A pulse of a tracer gas was introduced into stream flowing over one end face of the pellet. In the modified pulse-double response procedure, experimental moments of the response peaks of both reactan...
One-pot synthesis and characterization of colloidally robust rhodium(0) nanoparticles catalyst: exceptional activity in the dehydrogenation of ammonia borane for chemical hydrogen storage
Ayvalı, Tuğçe; Özkar, Saim; Department of Chemistry (2011)
The production of transition metal(0) nanoparticles with controllable size and size distribution are of great importance in catalysis since their catalytic activity decreases as nanoparticles aggregate into clumps and ultimately to the bulk metal. Reducing the particle size of heterogeneous catalyst provides a significant rise in its activity as the fraction of surface atoms increases with decreasing particle size. Therefore, transition metal(0) nanoparticles need to be stabilized to certain extend in their...
A moment technique for adsorption rate on metal surfaces of supported catalysts CO adsorption on Pt-Al2O3 washcoated monolith
Dogu, G; Ozkan, G; Doğu, Timur (2001-12-15)
A moment technique was developed for the investigation of adsorption on metal surfaces of supported catalysts. The technique was applied to the evaluation of adsorption rate parameters of CO on a Pt-Al2O3 washcoated monolith. The adsorption rate constants evaluated in the temperature range 273-316 K showed significant decrease with an increase in surface coverage. Results of pulse response experiments corresponding to zero coverage gave the apparent activation energy for adsorption as 21 kJ/mol. This method...
Application of the Pippard relations to ammonia near the melting point
Yurtseven, Hasan Hamit (1999-09-01)
This study gives our application of the Pippard relations to the ammonia near its melting point. The Pippard relations between the specific heat C-P, the thermal expansivity alpha(P) and the isothermal compressibility kappa(T), have been established for the ammonia near its melting point. We have obtained that the Pippard relations are valid for the ammonia. We give here an evidence that on the basis of the experimental data the critical transition in this system near its melting point can be considered as ...
Intensity vector direction exploitation for exhaustive blind source separation of convolutive mixtures
Günel Kılıç, Banu; Hacıhabiboğlu, Hüseyin (2009-04-19)
This article presents a technique that uses the intensity vector direction exploitation (IVDE) method for exhaustive separation of convolutive mixtures. While only a four-element compact sensor array is used, multiple channels for all possible source directions are produced by exhaustive separation. Singular value decomposition (SVD) is then applied to determine the signal subspace and the directions of the local maxima of the signal energy. This information is then used to select the channels containing th...
Citation Formats
T. Doğu, G. Dogu, B. McCoy, and J. Smith, “One-sided single-pellet technique for adsorption and intraparticle diffusion,” AICHE JOURNAL, pp. 516–523, 1996, Accessed: 00, 2020. [Online]. Available: