Alteration of birnessite reactivity in dynamic anoxic/oxic environments

Autor: Qinzhi Li, Dieter Schild, Mathieu Pasturel, Johannes Lützenkirchen, Khalil Hanna
Přispěvatelé: Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Karlsruhe Institute of Technology (KIT), Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Journal of Hazardous Materials, 433, Art.Nr.: 128739
Journal of Hazardous Materials
Journal of Hazardous Materials, 2022, 433, pp.128739. ⟨10.1016/j.jhazmat.2022.128739⟩
ISSN: 0304-3894
1873-3336
DOI: 10.5445/ir/1000145277
Popis: International audience; Although the oxidative capacity of manganese oxides has been widely investigated, potential changes of the surface reactivity in dynamic anoxic/oxic environments have been often overlooked. In this study, we showed that the reactivity of layer structured manganese oxide (birnessite) was highly sensitive to variable redox conditions within environmentally relevant ranges of pH (4.0 - 8.0), ionic strength (0-100 mM NaCl) and Mn(II)/MnO(2) molar ratio (0-0.58) using ofloxacine (OFL), a typical antibiotic, as a target contaminant. In oxic conditions, OFL removal was enhanced relative to anoxic environments under alkaline conditions. Surface-catalyzed oxidation of Mn(II) enabled the formation of more reactive Mn(III) sites for OFL oxidation. However, an increase in Mn(II)/MnO(2) molar ratio suppressed MnO(2) reactivity, probably because of competitive binding between Mn(II) and OFL and/or modification in MnO(2) surface charge. Monovalent cations (e.g., Na(+)) may compensate the charge deficiency caused by the presence of Mn(III), and affect the aggregation of MnO(2) particles, particularly under oxic conditions. An enhancement in the removal efficiency of OFL was then confirmed in the dynamic two-step anoxic/oxic process, which emulates oscillating redox conditions in environmental settings. These findings call for a thorough examination of the reactivity changes at environmental mineral surfaces (e.g., MnO(2)) in natural systems that may be subjected to alternation between anaerobic and oxygenated conditions.
Databáze: OpenAIRE
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