Carboxyl-richness controls organic carbon preservation during coprecipitation with iron (oxyhydr)oxides in the natural environment

DOI: 10.1038/s43247-021-00301-9

Authors: Lisa Curti (University of Leeds) , Oliver W. Moore (University of Leeds) , Peyman Babakhani (University of Leeds) , Ke-Qing Xiao (University of Leeds) , Clare Woulds (University of Leeds) , Andrew W. Bray (University of Leeds) , Ben J. Fisher (University of Leeds) , Majid Kazemian (Diamond Light Source) , Burkhard Kaulich (Diamond Light Source) , Caroline L. Peacock (University of Leeds)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Communications Earth & Environment , VOL 2

State: Published (Approved)
Published: November 2021
Diamond Proposal Number(s): 21323 , 20839 , 23049

Abstract: The coprecipitation of organic carbon with iron minerals is important for its preservation in soils and sediments, but the mechanisms for carbon-iron interactions and thus the controls on organic carbon cycling are far from understood. Here we coprecipitate carboxylic acids with iron (oxyhydr)oxide ferrihydrite and use near-edge X-ray absorption fine structure spectroscopy and wet chemical treatments to determine the relationship between sequestration mechanism and organic carbon stability against its release and chemical oxidative remineralisation. We show that organic carbon sequestration, stabilisation and persistence increase with an increasing number of carboxyl functional groups. We suggest that carboxyl-richness provides an important control on organic carbon preservation in the natural environment. Our work offers a mechanistic basis for understanding the stability and persistence of organic carbon in soils and sediments, which might be used to develop an overarching relationship between organic functional group-richness, mineral interactions and organic carbon preservation in the Earth system.

Journal Keywords: Carbon cycle; Geochemistry; Marine chemistry; Mineralogy

Subject Areas: Earth Science, Chemistry, Environment


Instruments: I08-Scanning X-ray Microscopy beamline (SXM)

Added On: 09/11/2021 09:36

Documents:
s43247-021-00301-9.pdf

Discipline Tags:

Earth Sciences & Environment Mineralogy Climate Change Chemistry Geology Geochemistry

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) Near Edge X-ray Absorption Fine Structures (NEXAFS)