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Title: Photo-production of Reactive Oxygen Species and Degradation of Dissolved Organic Matter by Hematite Nanoplates Functionalized by Adsorbed Oxalate

Journal Article · · Environmental Science: Nano
DOI:https://doi.org/10.1039/D0EN00365D· OSTI ID:1668797

The geochemical cycling of iron and carbon can couple in unique ways in the euphotic zone of aquatic systems. For example, the prevalence of hematite nanoparticles and low molecular weight organics that can functionalize their surfaces, such as oxalate, creates a solar- photoactive interfacial system capable of generating reactive oxygen species (ROS) that degrade natural organic matter. Here we report a systematic study of this pathway and its efficiency to mineralize model chromophoric dissolved organic matter (DOM) compounds into CO2 under mildly acidic conditions. When illuminated, synthetic hematite nanoplates coated with adsorbed oxalate undergo ligand-to-metal charge transfer yielding Fe(II) via photoreductive dissolution, while oxalate decomposes into the carboxyl anion radical •CO2- as detected by electron paramagnetic spectroscopy using selective spin trap compounds. This important radical quickly reduces molecular oxygen into hydrogen peroxide, which initiates the canonical Fenton reactions that yield hydroxyl radical via Fe(II)/Fe(III) valence cycling. Production of hydroxyl radical in this photocatalytic system is shown to efficiently degrade the pseudo-DOM chromophore RhB, as well as two natural water-extractable chromophoric DOM compounds from agricultural soils, characterized in molecular detail using Fourier transform ion cyclotron resonance mass spectrometry, nuclear magnetic resonance, infrared and fluorescence spectroscopies. The study highlights the photocatalytic interactions that can occur between common iron oxide nanoparticles, low molecular weight dicarboxylic acids, and dissolved organic matter that can couple their steady-state fluxes in the euphotic zone, pointing to the importance of light-induced ROS generation as a key mechanism.

Research Organization:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC05-76RL01830
OSTI ID:
1668797
Report Number(s):
PNNL-SA-148918
Journal Information:
Environmental Science: Nano, Vol. 7, Issue 8
Country of Publication:
United States
Language:
English

References (64)

Natural, incidental, and engineered nanomaterials and their impacts on the Earth system journal March 2019
Nanominerals, Mineral Nanoparticles, and Earth Systems journal March 2008
Facet-Dependent Cr(VI) Adsorption of Hematite Nanocrystals journal January 2016
The interplay of microbially mediated and abiotic reactions in the biogeochemical Fe cycle journal October 2014
Evolution of the nitrogen cycle and its influence on the biological sequestration of CO2 in the ocean journal May 1997
Biogeochemical Controls and Feedbacks on Ocean Primary Production journal July 1998
The Biogeochemical Cycles of Trace Metals in the Oceans journal May 2003
Biogeochemical Redox Processes and their Impact on Contaminant Dynamics journal January 2010
Ascorbate-Promoted Surface Iron Cycle for Efficient Heterogeneous Fenton Alachlor Degradation with Hematite Nanocrystals journal March 2017
Hematite facet confined ferrous ions as high efficient Fenton catalysts to degrade organic contaminants by lowering H2O2 decomposition energetic span journal February 2016
Photochemical cycling of iron in the surface ocean mediated by microbial iron(iii)-binding ligands journal September 2001
Ascorbate Induced Facet Dependent Reductive Dissolution of Hematite Nanocrystals journal January 2017
A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization journal October 2000
Deep carbon export from a Southern Ocean iron-fertilized diatom bloom journal July 2012
Microheterogeneity of Singlet Oxygen Distributions in Irradiated Humic Acid Solutions journal March 2006
Molecular characterization of dissolved organic matter (DOM): a critical review journal September 2012
CHEMISTRY: Enhanced: Dissolved Natural Organic Matter as a Microreactor journal March 2006
Heterogeneous Photodegradation of Pentachlorophenol with Maghemite and Oxalate under UV Illumination journal November 2008
Heterogeneous photodegradation of pentachlorophenol and iron cycling with goethite, hematite and oxalate under UVA illumination journal February 2010
The critical role of the surface iron-oxalate complexing species in determining photochemical degradation of norfloxacin using different iron oxides journal December 2019
Atrazine Degradation in Irradiated Iron/Oxalate Systems:  Effects of pH and Oxalate journal July 1999
Evidence for redox cycling of iron in atmospheric water droplets journal March 1990
Photochemical Cycling of Iron Mediated by Dicarboxylates: Special Effect of Malonate journal January 2010
Iron Redox Cycling in Surface Waters:  Effects of Humic Substances and Light journal April 1997
Chemical characterization of dissolved organic matter (DOM): A prerequisite for understanding UV-induced changes of DOM absorption properties and bioavailability journal March 2009
Hydroxyl Radical Photoproduction in the Sea and Its Potential Impact on Marine Processes journal November 1990
Facet-Specific Photocatalytic Degradation of Organics by Heterogeneous Fenton Chemistry on Hematite Nanoparticles journal August 2019
Continuous Shape- and Spectroscopy-Tuning of Hematite Nanocrystals journal September 2010
Improved WATERGATE Pulse Sequences for Solvent Suppression in NMR Spectroscopy journal May 1998
Highly Mobile Iron Pool from a Dissolution−Readsorption Process journal July 2008
Adsorption of oxalate and malonate at the water-goethite interface: Molecular surface speciation from IR spectroscopy journal February 2005
Mechanism of Ferric Oxalate Photolysis journal June 2017
Mechanisms of dissolution of iron oxides in aqueous oxalic acid solutions journal September 1996
Dissolution of hematite in acidic oxalate solutions: the effect of ferrous ions addition journal November 1996
Hydroxylamine Promoted Goethite Surface Fenton Degradation of Organic Pollutants journal April 2017
Nanostructured hematite: synthesis, characterization, charge carrier dynamics, and photoelectrochemical properties journal January 2012
Facile synthesis of carbon-coated hematite nanostructures for solar water splitting journal January 2013
Intermediate free radicals in the oxidation of wastewaters journal April 2002
Theoretical and Experimental Studies of the Spin Trapping of Inorganic Radicals by 5,5-Dimethyl-1-Pyrroline N -Oxide (DMPO). 1. Carbon Dioxide Radical Anion journal December 2006
Analysis of the oxidant in photooxidation reactions journal March 1967
Iron(III) Catalyzed Photochemical Reduction of Chromium(VI) by Oxalate and Citrate in Aqueous Solutions journal January 1997
Reduction potential of the carboxyl radical anion in aqueous solutions journal April 1989
Yield of Carboxyl Anion Radicals in the Photocatalytic Degradation of Formate over TiO 2 Particles journal December 2001
Thermochemistry of Proton-Coupled Electron Transfer Reagents and its Implications journal December 2010
Role of Proton-Coupled Electron Transfer in O–O Bond Activation journal July 2007
Formation of hydrogen peroxide and depletion of oxalic acid in atmospheric water by photolysis of iron(III)-oxalato complexes journal May 1992
Evidence for Photochemical Formation of H2O2 and Oxidation of SO2 in Authentic Fog Water journal April 1993
On some fundamental reactions in radiation chemistry: Nanosecond pulse radiolysis journal January 1976
An in vivo ESR spin-trapping study: Free radical generation in rats from formate intoxication-- role of the Fenton reaction journal November 2001
Critical Review of rate constants for reactions of hydrated electrons, hydrogen atoms and hydroxyl radicals (⋅OH/⋅O in Aqueous Solution
  • Buxton, George V.; Greenstock, Clive L.; Helman, W. Phillips
  • Journal of Physical and Chemical Reference Data, Vol. 17, Issue 2 https://doi.org/10.1063/1.555805
journal April 1988
What happens to terrestrial organic matter in the ocean? journal November 1997
Spatial distribution of riverine DOC inputs to the ocean: an updated global synthesis journal May 2012
Molecular Signatures of Biogeochemical Transformations in Dissolved Organic Matter from Ten World Rivers journal September 2016
Changes in the compound classes of dissolved organic matter along an estuarine transect: A study using FTIR and 13C NMR journal July 2010
HPLC-SEC-FTIR characterization of the dissolved organic matter produced by the microbial carbon pump journal September 2019
Fluorescence analysis of dissolved organic matter in natural, waste and polluted waters—a review journal January 2007
High-field NMR spectroscopy and FTICR mass spectrometry: powerful discovery tools for the molecular level characterization of marine dissolved organic matter journal January 2013
Proposed Guidelines for Solid Phase Extraction of Suwannee River Dissolved Organic Matter journal June 2016
Major Structural Components in Freshwater Dissolved Organic Matter journal December 2007
Characterization of a major refractory component of marine dissolved organic matter journal June 2006
Oxidized sterols as a significant component of dissolved organic matter: Evidence from 2D HPLC in combination with 2D and 3D NMR spectroscopy journal June 2012
Organic acids in the rhizosphere – a critical review journal August 1998
Iron Dissolution of Dust Source Materials during Simulated Acidic Processing: The Effect of Sulfuric, Acetic, and Oxalic Acids journal August 2013
Quantitative Relationships Between soil Color and Hematite Content journal January 1983

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