Interaction between organic vapors and clinoptilolite–mordenite rich tuffs in parent, decationized, and lead exchanged forms

Acid natural clinoptilolite: Structural properties against adsorption/separation of n-paraffins

“…9). The greater Q dif values obtained by us with respect to those reported by Elizalde-González and Pérez-Cruz [3,21] for n-C 5 H 12 -n-C 8 H 18 in Mexican and Hungarian zeolites could be due to the high content of mordenite in their samples (around 30%). The greater dimensions of the channel of twelve-membered rings of the mordenite (0.70 Â 0.65 nm [43]) imply a smaller interaction with the n-paraffin molecules, which contributes to decrease the differential heat of adsorption.…”

“…The spectra of the solid samples were obtained at room temperature using an ASX-300 Bruker spectrometer at 78.2 MHz, with a pulse length of 3.00 ls at 30°, a recycle time of 1 s, and a spinning rate of 10 kHz. A total of 2048 scans were accumulated and referenced to Al(NO 3 ) 3 . In order to compare the spectra under the same experimental conditions, similar amounts of samples were used to fill the rotor for NMR measurements.…”

“…In particular, in the zeolites, such interactions can occur with the framework, the exchangeable cations, and the acidic and basic sites [1]. Clinoptilolite is one of the most abundant and economically important natural zeolites, so it has been the subject of many characterization studies, with emphasis in its adsorption behavior relative to different compounds [2][3][4].…”

“…The authors observed the decrease in the amount of native cations and the dealumination of the framework, without alteration of the NZ structure. However, as far as we know, the adsorption properties of clinoptilolites aimed at the capture of n-paraffins and the use of inverse gas chromatography (IGC) method for such purpose have been barely studied in the literature [3,20,21].…”

Separation of N–C5H12–C9H20 Paraffins Using Boehmite by Inverse Gas Chromatography

“…An important experimental feature is the low column temperature necessary to separate n-paraffins (C5-C9). As reported in previous studies, the separation of n-C3-n-C7 mixtures in hexacyanocobaltates [18], n-C3-n-C9 mixtures in clinoptilolite [19] and n-paraffins and aromatics in zeolites, elution temperatures above 127 • C were required [40]. Instead, the separation of n-C5-n-C9 mixtures in a larger boehmite column (90 cm) was achieved at elution temperatures below 77 • C. These data were a first indication that the non-specific interactions between n-paraffins and boehmite were lower than those present in the other two adsorbents.…”