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Journal article
Temperature and pH Affect the Sorption and Transformation of Dissolved Organic Carbon by Birnessite
ACS Earth and Space Chemistry, Vol.8(10), pp.2012-2026
19/09/2024
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Abstract
Soil mineralogy plays a vital role in carbon storage. Birnessite is a widely occurring manganese oxide mineral. Despite its widespread occurrence, studies of the interactions between natural soil organic carbon and manganese oxide minerals are rare. This study investigated the influence of triclinic birnessite on the transformation of vermicompost-derived dissolved organic carbon (DOC) at different pHs (4 and 8) and temperatures (25 and 50 °C). Enhanced adsorption and transformation of DOC, particularly at pH 4 and 50 °C, were observed. The use of SUVA254 and fluorescence spectroscopy showed that DOC sorption caused an increase in carbon aromaticity, with the highest degree observed at pH 4 at 50 °C. In particular, X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure C 1s characterization showed an 8-fold increase in aromaticity at 50 °C compared to the unreacted DOC, with esterification and/or etherification reactions also occurring at pH 4. The impact of DOC sorption on birnessite stability and transformations was also assessed via X-ray absorption near-edge structure spectroscopy, which revealed that reacted and unreacted triclinic birnessite showed modest changes to Mn II, III, and IV. Manganese K-edge extended X-ray absorption fine structure spectroscopy showed the increased formation of hexagonal birnessite at pH 4, the formation of manganite at pH 4 and 8, 50 °C, and the formation of up to 6% ramsdellite at pH 8, 25 °C. This study provides new insights into the role of birnessite in soil carbon storage and manganese mineral transformations under environmentally relevant conditions.
Details
- Title
- Temperature and pH Affect the Sorption and Transformation of Dissolved Organic Carbon by Birnessite
- Creators
- Oluwadunsin Oyetunji - RMIT UniversityDane Lamb - RMIT UniversityOliver A. H. Jones - RMIT UniversitySuresh Subashchandrabose - LoamBio, Building 1120, 346 Leeds Parade, Orange, New South Wales 2800, AustraliaEdward D. Burton - Southern Cross University
- Publication Details
- ACS Earth and Space Chemistry, Vol.8(10), pp.2012-2026
- Publisher
- American Chemical Society
- Grant note
- Australian Nuclear Science and Technology Organization (ANSTO): AS232/MEX1/20080, AS233/SXR/20555 Australian government
The authors wish to acknowledge the contribution of the Australian Nuclear Science and Technology Organization (ANSTO) in the award of the Medium Energy XAS (AS232/MEX1/20080) and Soft X-ray spectroscopy (AS233/SXR/20555) beamtimes. We appreciate the contributions of beamline scientists Dr. Emily Finch, Dr. Anton Tadich, Dr. Bruce Cowie, and Dr. Lars Thomsen. The authors also acknowledge the facilities and the scientific and technical assistance of the RMIT Microscopy and Microanalysis Facility (RMMF), a laboratory linked to Microscopy Australia enabled by NCRIS and the Micro Nano Research Facility (MNRF). The authors are grateful to the Australian government for the award of a Research Training place Ph.D. scholarship administered by RMIT University to the first author.
- Identifiers
- 991013224407902368
- Copyright
- Copyright © 2024 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY-NC-ND 4.0 .
- Academic Unit
- Faculty of Science and Engineering; Science
- Language
- English
- Resource Type
- Journal article