Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.1016/j.cej.2025.171796 |
Licence  |
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| Title (Primary) | Mechanistic insights into iron sulfide surface-mediated homolytic peroxydisulfate cleavage and high-valent iron-oxo formation in water |
| Author | Guo, P.; Mackenzie, K.
; Li, H.; Wu, L.; Sühnholz, S. |
| Source Titel | Biochemical Engineering Journal |
| Year | 2025 |
| Department | TECH |
| Page From | art. 171796 |
| Language | englisch |
| Topic | T7 Bioeconomy |
| Supplements | Supplement 1 |
| Keywords | Iron sulfide crystal; Peroxydisulfate activation; Catalytic properties; High-valent iron-oxo; Homolytic cleavage |
| Abstract | Homolytic activation of peroxydisulfate (PS) by iron sulfides (FexSy) is a promising alternative to conventional electron-transfer methods for generating sulfate radicals (SO4•−), yet the influence of FexSy crystallography on the surface-mediated mechanism remains unresolved. In this study, various FexSy
crystals of pyrite, mackinawite, and troilite were synthesized to
perform the first detailed elucidation of the surface-mediated PS
activation mechanism. This showed the stoichiometric activation of PS by
the prepared FexSy was at least 70 times higher
than the theoretical value, demonstrating the presence of a highly
efficient PS activation pathway. DFT calculations showed that the
elongation of the O O bond length from 1.230 to 1.509 Å, observed after bonding with 3d Fe orbitals of pyrite and troilite, suggests that PS molecules are more easily cleaved by a homolytic process leading to two SO4•−. The respective dominant radicals were subsequently determined by kinetic isotope effect, demonstrating that SO4•−
formation was more pronounced in pyrite (KIE = 2.01), whereas the
passivated troilite surface (KIE = 1.42–1.52) and instable mackinawite
structure (KIE = 1.92) affected its generation and existence.
Furthermore, our findings indicate that FeIV=O2+ formation is primarily enabled by the presence of SO4•−,
which facilitates a one-electron transfer through a homogeneous
process. The investigation of PS activation process reveals that iron
sulfides containing pyrite supports longer-term PS activation and higher
stability compared to troilite and mackinawite. These mechanistic and
structure-activity relationship insights are important for the rational
design of next-generation FexSy catalysts for SO4•−-based Advanced Oxidation Processes (AOPs). |
| Persistent UFZ Identifier | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=31746 |
| Guo, P., Mackenzie, K., Li, H., Wu, L., Sühnholz, S. (2025): Mechanistic insights into iron sulfide surface-mediated homolytic peroxydisulfate cleavage and high-valent iron-oxo formation in water Biochem. Eng. J. , art. 171796 10.1016/j.cej.2025.171796 |
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