The expansion of chemical and petrochemical industries in response to the increasing demand of energy and consumer goods of different topologies, has generated in the recent years a significantly increase of the water contamination. The major pollutants, that deriving from this industrial processes, are included among the Emerging Organic Contaminants, specifically Volatile Organic Compounds (VOCs) require the most attention due to their harmful effects both on the environment and human health, even at very low concentrations. Due to the toxic effects of these chemicals also at long term, the removal or the reduce of concentrations of these class of pollutants from water bodies is today a very important objective. Often, the traditional water treatments (i.e., vaporization, dilution, decomposition, and reactions to sunlight action) need to been supported by new technologies and methods. For instance, adsorption technologies based on the use of adsorbent materials have been shown to be an effective and eco-friendly alternative to substitute or support the traditional methods. Among the adsorbent materials, hydrophobic zeolites have proven to be very promising materials, regarding the successful removal of several representatives of VOCs (Pasti et al. 2016). By an environmental impact point of view, zeolites also have another very interest aspect. In fact, they can be easily regenerated by thermal processes without changing their initial adsorption features. On the basis of the above statements, to contribute to the growth of knowledge on these materials applied in this field, the combination of chromatographic, diffractometric and thermogravimetric techniques has been employed to investigate the fuel-based compounds adsorptive-desorptive process. In particular, the behaviour of ZSM-5 (hydrophobic and synthetic zeolite) has been studied. Concerning the study of the desorption process, time-resolved high-temperature synchrotron X-ray powder diffraction was used as a tool to understand the structural modification undergoing on ZSM-5 framework during the desorption of 1,2 dichloroethane, toluene, and methyl tert-butyl ether. Specifically, the X-ray powder diffraction patterns are collected from room temperature to 600 °C. The results achieved by means of Rietveld refinements of the investigated compounds highlight the “out-of-equilibrium effects” that govern the adsorption/desorption dynamic conditions in ZSM-5 powders (Rodeghero et al., 2017). Pasti L., Rodeghero E., Sarti E., Bosi V., Cavazzini A., Bagatin R. & Martucci A. 2016. Competitive adsorption of VOCs from binary aqueous mixtures on zeolite ZSM-5. RSC Advance,6, 54544–54552. Rodeghero E., Pasti L., Sarti E., Cruciani G., Martucci A. 2017. Temperature-induced desorption of Methyl tert-butyl ether confined on ZSM-5: a combined in situ synchrotron XRD powder diffraction and chromatographic study. Minerals, 34,1–9.
ADSORPTION AND DESORPTION OF FUEL-BASED COMPOUNDS FROM WATER THROUGH SYNTHETIC ZEOLITE ZSM-5
RODEGHERO E.
;MARTUCCI A.;PASTI L.;CRUCIANI G.
2017
Abstract
The expansion of chemical and petrochemical industries in response to the increasing demand of energy and consumer goods of different topologies, has generated in the recent years a significantly increase of the water contamination. The major pollutants, that deriving from this industrial processes, are included among the Emerging Organic Contaminants, specifically Volatile Organic Compounds (VOCs) require the most attention due to their harmful effects both on the environment and human health, even at very low concentrations. Due to the toxic effects of these chemicals also at long term, the removal or the reduce of concentrations of these class of pollutants from water bodies is today a very important objective. Often, the traditional water treatments (i.e., vaporization, dilution, decomposition, and reactions to sunlight action) need to been supported by new technologies and methods. For instance, adsorption technologies based on the use of adsorbent materials have been shown to be an effective and eco-friendly alternative to substitute or support the traditional methods. Among the adsorbent materials, hydrophobic zeolites have proven to be very promising materials, regarding the successful removal of several representatives of VOCs (Pasti et al. 2016). By an environmental impact point of view, zeolites also have another very interest aspect. In fact, they can be easily regenerated by thermal processes without changing their initial adsorption features. On the basis of the above statements, to contribute to the growth of knowledge on these materials applied in this field, the combination of chromatographic, diffractometric and thermogravimetric techniques has been employed to investigate the fuel-based compounds adsorptive-desorptive process. In particular, the behaviour of ZSM-5 (hydrophobic and synthetic zeolite) has been studied. Concerning the study of the desorption process, time-resolved high-temperature synchrotron X-ray powder diffraction was used as a tool to understand the structural modification undergoing on ZSM-5 framework during the desorption of 1,2 dichloroethane, toluene, and methyl tert-butyl ether. Specifically, the X-ray powder diffraction patterns are collected from room temperature to 600 °C. The results achieved by means of Rietveld refinements of the investigated compounds highlight the “out-of-equilibrium effects” that govern the adsorption/desorption dynamic conditions in ZSM-5 powders (Rodeghero et al., 2017). Pasti L., Rodeghero E., Sarti E., Bosi V., Cavazzini A., Bagatin R. & Martucci A. 2016. Competitive adsorption of VOCs from binary aqueous mixtures on zeolite ZSM-5. RSC Advance,6, 54544–54552. Rodeghero E., Pasti L., Sarti E., Cruciani G., Martucci A. 2017. Temperature-induced desorption of Methyl tert-butyl ether confined on ZSM-5: a combined in situ synchrotron XRD powder diffraction and chromatographic study. Minerals, 34,1–9.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
