Dissolved Organic Matter Sorption and Molecular Fractionation by Naturally Occurring Bacteriogenic Iron (Oxyhydr)oxides

Abstract

Iron (oxyhydr)­oxides are highly reactive, environmentally ubiquitous organic matter (OM) sorbents that act as mediators of terrestrial and aqueous OM cycling. However, current understanding of environmental iron (oxyhydr)­oxide affinity for OM is limited primarily to abiogenic oxides. Bacteriogenic iron (oxyhydr)­oxides (BIOs), common to quiescent waterways and soil redox transitions, possess a high affinity for oxyanions (i.e., arsenate and chromate) and suggests that BIOs may be similarly reactive for OM. Using adsorption and desorption batch reactions, paired with Fourier transform infrared spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry, this work demonstrates that BIOs are capable of sorbing leaf litter-extracted DOM and Suwannee River Humic/Fulvic Acid (SRHA/SRFA) and have sorptive preference for distinct organic carbon compound classes at the biomineral interface. BIOs were found to sorb DOM and SRFA to half the extent of 2-line ferrihydrite per mass of sorbent and was resilient to desorption at high ionic strength and in the presence of a competitive ligand. We observed the preferential sorption of aromatic and carboxylic-containing species and concurrent solution enrichment of aliphatic groups unassociated with carboxylic acids. These findings suggest that DOM cycling may be significantly affected by BIOs, which may impact nutrient and contaminant transport in circumneutral environments.

Interaction of pig manure-derived dissolved organic matter with soil affects sorption of sulfadiazine, caffeine and atenolol pharmaceuticals

“…Going along with the soil sorption of manure DOM, the chemical composition of solutions was strongly (Engel & Chefetz, 2015Sowers et al, 2019).…”

Iron Flocs and the Three Domains: Microbial Interactions in Freshwater Iron Mats

“…Biogenically produced iron oxides, sometimes referred to as bacteriogenic iron oxides (both use the acronym BIOS) in the literature, have been previously shown to remove phosphorous from solution by adsorption in freshwater as well as other environments, such as marine waters and soils (16)(17)(18). Interestingly, there is also evidence that DOC may adsorb to the surfaces of BIOS as well, potentially competing with phosphorous (19,20) for surface area. While the geochemistry of the iron mat is certainly variable, as shown in the above examples of phosphorous and DOC dynamics, in a freshwater iron mat there are two constants, dissolved oxygen and reduced iron (Fe 21 ), with opposing gradients (Fig.…”

Direct analysis of fulvic acids adsorbed onto capped gold nanoparticles by laser desorption ionization Fourier-transform ion cyclotron resonance mass spectrometry

“…14,15 FT-ICR-MS with electrospray ionization (ESI) has been used to analyze compositional differences in NOM solutions before and after contact with mineral surfaces. [16][17][18][19][20][21][22][23] Using such an indirect approach, the molecular composition of a corona formed by NOM on silver (Ag) NPs coated with citrate was previously described. 24 However, the limited sensitivity of the indirect detection method usually requires low NOM : NP ratios, which may affect the selectivity of the NOM sorption as compared to natural systems.…”