Details zur Publikation

Kategorie Textpublikation
Referenztyp Zeitschriften
DOI 10.1016/j.cej.2022.138192
Volltext Autorenversion
Titel (primär) Heterogeneous activation of persulfate by FeS – Surface influence on selectivity
Autor Sühnholz, S.; Kopinke, F.-D.; Mackenzie, K. ORCID logo
Quelle Chemical Engineering Journal
Erscheinungsjahr 2022
Department TUCHEM
Band/Volume 450, Part 3
Seite von art. 138192
Sprache englisch
Topic T7 Bioeconomy
Keywords persulfate activation; surface-associated sulfate radicals; iron sulfide; hydrogen kinetic isotope effects; second-order rate constants

Recently, several studies have been published on sulfate radicals as strong oxidants and methods of their generation. A shift from homogeneous to heterogeneous methods can be observed for persulfate activation as a means of generating sulfate radicals. However, to date, the influence of the surface on the radical chemistry has not been examined in detail.

In the present study, homogeneous persulfate activation methods (elevated temperature and dissolved iron(II)) are compared with heterogeneous activation by FeS. The selectivity patterns for the oxidation of chlorinated ethenes, ethanes and benzenes differ notably depending on the persulfate activation method. The obtained kinetic data are in conformity with the hypothesis that sulfate radicals generated at the FeS surface have different selectivities than freely dissolved radicals. The assumption of different reactive species is further confirmed by the determination of hydrogen kinetic isotope effects (H-KIEs) for the oxidation of methanol isotopologues with sulfate radicals using the set of activation methods. The H-KIE obtained in the heterogeneous system (H-KIEFeS = 3.0 ± 0.3) is significantly higher than for the homogeneous system (H-KIEhom = 2.3 ± 0.1). This leads us to the conclusion that sulfate radicals generated on the FeS surface react as surface-associated radicals, which show a different selectivity pattern than freely dissolved radicals.

Furthermore, the apparent second-order rate constants in homogenous solution at ambient temperature, ranging from 5·107 to 1.7·109 M-1s-1, were determined for the reaction of sulfate radicals with various chlorinated hydrocarbons under study.

dauerhafte UFZ-Verlinkung
Sühnholz, S., Kopinke, F.-D., Mackenzie, K. (2022):
Heterogeneous activation of persulfate by FeS – Surface influence on selectivity
Chem. Eng. J. 450, Part 3 , art. 138192 10.1016/j.cej.2022.138192