Determination of the Henry Constant for Zeolite-VOC Systems Using Massic and Chromatographic Adsorption Data

Abstract

Both the inverse gas chromatographic method and the dynamic gravimetric-calorimetric method were tested in order to determine the Henry constant for toluene on a Na-faujasite type zeolite. We used the pulse technique for the chromatographic method and a system generating low concentration of VOC in a helium flow for the gravimetric technique. The experimental determinations of the Henry constants for toluene were achieved in two different temperature ranges (from 363 to 548 K for gravimetry and from 548 to 673 K for chromatography). The results presented in this paper show the complementarity of two different techniques for the Henry constants determination. The Henry constants obtained with the two techniques at 548 K differ from 8%.

Adsorption of Alkanes and Aromatic Compounds on Various Faujasites in the Henry Domain. 1. Compensating Cation Effect on Zeolites Y

“…The Li + -, K + -, Rb + -, and Cs + -exchanged faujasites are obtained by ion exchange of the NaY material with a chloride solution of the corresponding alkali cation as described by Townsend. 19 The powder of the NaY zeolite is dispersed in a 6 M chloride solution. The suspension is then heated at 353.15 K over 4 h. The hot mixture is filtered and washed with distilled water to remove Clions.…”

“…The first moment of this profile is related to the Henry constant by eq 1. − ,,, with ε = ε i + ε p (1 − ε i ) and where μ is the retention time (s); V column is the column volume (m 3 ); V d is the dead volume between the injector and the detector (m 3 ); Q T is the total volume flow (m 3 ·s -1 ); T is the bed temperature (K); R is the ideal gas constant (J·K -1 ·mol -1 ); ε is the total porosity; ε i is the interstitial bed porosity; ε p is the pellet macroporosity; ρ c is the crystal density (kg·m -3 ); and K ‘ is the Henry constant (mol·kg -1 ·Pa -1 ).…”

Gravimetrische Messungen von Transportkoeffizienten von n‐Alkanen am 5A‐Zeolith

“…B. Abluft von Industrieanlagen, eine wichtige und häufig angewandte Methode dar [1,2]. Die durch Adsorptionsvorgänge nutzbare Separation von Gasgemischen kann prinzipiell auf drei verschiedenen Mechanismen, dem sterischen Ausschluss, einem kinetischen Effekt und einem thermodynamischen Effekt, erfolgen [3,4].…”

Adsorption and Diffusion Properties of Toluene on Y Zeolites by Steam–Acid Treatment: Effects of Mesoporosity and Surface Acidity

“…As q gets closer to zero, the plot of ln­( p / q ) vs the loading q should approach a line, and Henry’s constant ( K H ) can be derived from the intercept −ln­( K H ). Moreover, the heat of adsorption at zero coverage Q st was obtained from the 1/ T dependence of ln­( K H ) in terms of van’s Hoff expression It can be seen from the data listed in Figure that Henry’s constant and the initial heats of adsorption for toluene in all of the samples decreased in the order of Y-0 < Y-1 < Y-2 < Y-3 < Y-4 < Y-5 < Y-6. These results are consistent with the changing tendency of b 1 and Q 1 values obtained by the fitting of the isotherms, reflecting again the reduction of the interaction between toluene and the Y zeolite surface with increasing mesopore volume and decreasing acidic site density after the steam–acid treatment.…”