Sulfur dioxide is an air pollutant mainly emitted from anthropogenic sources that has important effects on human health and on climate changes. [1] For this reason, the European Union ratified the 2016/2284/UE Regulation, which defines new and more severe reduction targets for a progressive reduction of SO2 emissions. The removal of sulfur dioxide from combustion flue gases can be accomplished by water-based desulfurization technologies which exploit the capacity of freshwater or seawater to solubilize and remove acid gases. SO2 removal is enhanced by adding an oxidant such as NaClO2 that converts the sulfurous (S(IV)) ions to the sulfuric (S(VI)) ions. Although the wet oxidation scrubbing of SO2 is a popular method for the removal of this poisonous gas, the oxidation mechanism occurring in such complex systems has not yet been elucidated. [2, 3] Accordingly, gas-phase studies performed by mass spectrometric techniques allow the molecularlevel investigation of the elementary steps of complex chemical processes, without the interference of the solution effects. Electrospray ionization mass spectrometry (ESI-MS) has also been long-time devoted to the study of salt speciation occurring in solution, showing its capability in controlling size and charge of the cluster ions. [4, 5] Considering the promising information that gas-phase studies can provide, here we investigate the reactions of [NaClO2⋅X]- cluster anions (X = halide ion; ClOx with x = 1-4) with SO2 by ion-molecule reaction experiments performed in an Ion Trap mass spectrometer, in-house modified to perform kinetic measurement. Intracluster oxidation of SO2 occurs by oxygen-atom, oxygen-ion and double oxygen transfer reactions, which may be a useful parallel to the pathways underlying the oxidation mechanism occurring in solution. [1] J.H. Seinfeld, S.N. Pandis, Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, 3th ed., John Wiley and Sons Inc, New York, 2016. [2] D. Flagiello, F. Di Natale, A. Erto, A. Lancia, Fuel, 2020, 277, 118055. [3] L. Zhao, Y. Sun, A. G. Chmielewski, A. Pawelec, S. Bułka, Plasma Chemistry and Plasma Processing, 2020, 40, 433. [4] A. Troiani, M. Rosi, C. Salvitti, G. de Petris, ChemPhysChem, 2014, 15, 2723. [5] C. Salvitti, M. Rosi, F. Pepi, A. Troiani, G. de Petris, Chem Phys Letters 2021, 776, 138555.
Intracluster sulfur dioxide oxidation in NaClO2 cluster anions: a mass spectrometric study / Troiani, Anna; Salvitti, Chiara; Pepi, Federico; DE PETRIS, Giulia. - 4:(2021), pp. 260-260. (Intervento presentato al convegno XXVII congresso nazionale della Società Chimica Italiana, SCI2021 tenutosi a Online).
Intracluster sulfur dioxide oxidation in NaClO2 cluster anions: a mass spectrometric study
Anna Troiani;Chiara Salvitti;Federico Pepi;Giulia de Petris
2021
Abstract
Sulfur dioxide is an air pollutant mainly emitted from anthropogenic sources that has important effects on human health and on climate changes. [1] For this reason, the European Union ratified the 2016/2284/UE Regulation, which defines new and more severe reduction targets for a progressive reduction of SO2 emissions. The removal of sulfur dioxide from combustion flue gases can be accomplished by water-based desulfurization technologies which exploit the capacity of freshwater or seawater to solubilize and remove acid gases. SO2 removal is enhanced by adding an oxidant such as NaClO2 that converts the sulfurous (S(IV)) ions to the sulfuric (S(VI)) ions. Although the wet oxidation scrubbing of SO2 is a popular method for the removal of this poisonous gas, the oxidation mechanism occurring in such complex systems has not yet been elucidated. [2, 3] Accordingly, gas-phase studies performed by mass spectrometric techniques allow the molecularlevel investigation of the elementary steps of complex chemical processes, without the interference of the solution effects. Electrospray ionization mass spectrometry (ESI-MS) has also been long-time devoted to the study of salt speciation occurring in solution, showing its capability in controlling size and charge of the cluster ions. [4, 5] Considering the promising information that gas-phase studies can provide, here we investigate the reactions of [NaClO2⋅X]- cluster anions (X = halide ion; ClOx with x = 1-4) with SO2 by ion-molecule reaction experiments performed in an Ion Trap mass spectrometer, in-house modified to perform kinetic measurement. Intracluster oxidation of SO2 occurs by oxygen-atom, oxygen-ion and double oxygen transfer reactions, which may be a useful parallel to the pathways underlying the oxidation mechanism occurring in solution. [1] J.H. Seinfeld, S.N. Pandis, Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, 3th ed., John Wiley and Sons Inc, New York, 2016. [2] D. Flagiello, F. Di Natale, A. Erto, A. Lancia, Fuel, 2020, 277, 118055. [3] L. Zhao, Y. Sun, A. G. Chmielewski, A. Pawelec, S. Bułka, Plasma Chemistry and Plasma Processing, 2020, 40, 433. [4] A. Troiani, M. Rosi, C. Salvitti, G. de Petris, ChemPhysChem, 2014, 15, 2723. [5] C. Salvitti, M. Rosi, F. Pepi, A. Troiani, G. de Petris, Chem Phys Letters 2021, 776, 138555.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
