Regeneration of high-silica zeolites after sulfamethoxazole antibiotic adsorption: a combined in situ high-temperature synchrotron X-ray powder diffraction and thermal degradation study

Abstract

The thermal regeneration of sulfamethoxazole (SMX)-loaded Y and ZSM-5 zeolites was studied using a combined in situ high-temperature synchrotron X-ray powder diffraction and thermal degradation study. The evolution of the structural features was monitored in real time in the 30À575ºC temperature range by full-profile Rietveld analysis. SMX thermal degradation pathways into high-silica zeolite antibiotic adducts, as well as the release of evolved species are similar to those for pure SMX. The adsorption/desorption process occurs without any significant loss of zeolite crystallinity, though slight deformations to the channel apertures are observed. Regenerated zeolites regain almost perfectly 'bare' (i.e. unloaded) material unit-cell parameters and only a slight memory effect, in terms of structural deformations induced by the process, is registered in the channel geometry. Interestingly, these changes do not affect the adsorption properties of the regenerated samples, which are able to re-adsorb comparable amounts of antibiotic molecules as in the first adsorption cycle.

Insights into Adsorption of Chlorobenzene in High Silica MFI and FAU Zeolites Gained from Chromatographic and Diffractometric Techniques

“…It can be seen that the saturation capacity of these zeolites are higher than those obtained with graphite materials (i.e., 28.3 mg/g for dichlorobenzene) [41], and in particular Y zeolite has a saturation value higher than adsorbents single-walled carbon nanotubes, especially if they are partially oxidized [42]. In addition HSZs can be regenerated without significant loss of their adsorption properties [5,6,29,30]. Therefore hydrophobic zeolites are very promising adsorbents for the removal of chlorinated aromatic compounds from water.…”

“…Additionally, based on the W sites refined distance these sites interact with both each other and chlorine atoms forming oligomers (W2-W2 = 2.93 Å, W3-Cl = 3.21 Å and W1-W2 = 2.93 and 2.74 Å, respectively) that strongly interact with the framework oxygen atoms via chlorine (Figure 4a). According to the recent literature [5][6][7][8][10][11][12][13]29,44], the strong interactions among organic molecules-H2O short chain-frameworks play a relevant role in stabilizing the guest structures within the zeolite porosity.…”

“…This work is part of a wider study aimed at systematically evaluating the adsorptive capacity of high silica zeolites (HSZ) (e.g., mordenite, ZSM-5, faujasite, beta, ferrierite [4,7,10,29,30]) for fuel-based compounds differing in chemical properties (e.g., polarity, functional groups, size, host-guest interactions, etc. ), which can provide useful information to accurately predict the behavior of HSZs as well as improve their individual performance.…”

“…Additionally, fast kinetics, mechanical, biological and chemical stability make them promising and efficient adsorbents [4,[6][7][8][26][27][28]. Furthermore, their high thermal stability guarantees the possibility of regeneration through thermal treatments in order to reintroduce them in new adsorption processes [5,[29][30][31][32][33].…”

Temperature-Induced Desorption of Methyl tert-Butyl Ether Confined on ZSM-5: An In Situ Synchrotron XRD Powder Diffraction Study

“…Thermal treatment is the most common regeneration technique, where organic host molecules are decomposed and/or oxidized at high temperature. Zeolites showed an excellent stability during the heating process and their behavior can be affected by several factors such as chemical composition, framework order-disorder and topology, nature and amount of extra-framework species, synthesis conditions, structure directing agents [21][22][23][24][25][26][27][28]. Consequently there is a strong interest in understanding the mechanisms behind the thermal regenerative solution which makes zeolites regenerable materials that are efficiently reusable in the contaminants adsorption process.…”