2 research outputs found
Electron Transfer Budgets and Kinetics of Abiotic Oxidation and Incorporation of Aqueous Sulfide by Dissolved Organic Matter
The reactivity of natural dissolved
organic matter toward sulfide
and has not been well studied with regard to electron transfer, product
formation, and kinetics. We thus investigated the abiotic transformation
of sulfide upon reaction with reduced and nonreduced Sigma-Aldrich
humic acid (HA), at pH 6 under anoxic conditions. Sulfide reacted
with nonreduced HA at conditional rate constants of 0.227–0.325
h<sup>–1</sup>. The main transformation products were elemental
S (S<sup>0</sup>) and thiosulfate (S<sub>2</sub>O<sub>3</sub><sup>2–</sup>), yielding electron accepting capacities of 2.82–1.75
μmol e<sup>–</sup> (mg C)<sup>−1</sup>. Native
iron contents in the HA could account for only 6–9% of this
electron transfer. About 22–37% of S reacted with the HA to
form organic S (S<sub>org</sub>). Formation of S<sub>org</sub> was
observed and no inorganic transformation products occurred for reduced
HA. X-ray absorption near edge structure spectroscopy supported S<sub>org</sub> to be mainly zerovalent, such as thiols, organic di- and
polysulfides, or heterocycles. In conclusion, our results demonstrate
that HA can abiotically reoxidize sulfide in anoxic environments at
rates competitive to sulfide oxidation by molecular oxygen or iron
oxides
Data and code for 'Uncovering a phylogenetic signal in plant biopolymer chemistry: a comparison of sporopollenin isolation approaches for use in palynological research'
R code and FTIR spectral data to recreate all analyses in the paper. Each data file contains the IR spectra for one experimental treatment, plus associated metadata.To run the R code, put all files into one folder, and set this as the working directory in the R session.</p