FeS colloids – formation and mobilization pathways in natural waters

Abstract

Reaction of Fe(iii)-(oxyhydr)oxides common in soil releases FeS nanoclusters that are stable in suspension and can be transported in groundwater.

Organic matter influences transformation products of ferrihydrite exposed to sulfide

“…Trends in total dissolved Fe (<0.22 μm, Fe aq ), which may include aqueous FeS clusters, 42 are shown in Fig. S6E and F. † Overall, Fe aq concentrations were low, accounting for <5 and ≤9% of total Fe present in the system after 1 week and 12 months, respectively.…”

“…To date, however, the impact of OM on the sulfidization kinetics and mineral transformation pathways of Fe(III)-(oxyhydr)oxides has received limited attention. [40][41][42] Henneberry et al 40 reacted Fe-OM flocs comprising natural OM collected from agricultural drainage waters with S(−II) (0.05 or 0.6 mM, molar ratios S(−II)/Fe = 0.014-0.46, C/Fe = 1.9-3.5). Results from X-ray diffraction (XRD) analyses did not indicate any change in floc crystallinity over 14 days.…”

Environmental Risk of Arsenic Mobilization from Disposed Sand Filter Materials

“…21 We define colloids as small particles subject to suspension and mobilization; this definition encompasses particles with size ranges that are beyond the traditionally considered 1-μm size cutoff. 22 An increase of mobilized colloidal Fe(III) (oxyhydr)oxides can further facilitate As(V) transport. 23,24 At the same time, colloidal Fe(III) (oxyhydr)oxides are known to be more susceptible to microbial reduction than larger mineral aggregates, therefore possibly promoting solubilization of Asbearing colloidal Fe(III) minerals.…”

Development of ReaxFF Reactive Force Field for Aqueous Iron–Sulfur Clusters with Applications to Stability and Reactivity in Water

“… 4 Some of the difficulties are due to the complicated electronic structure of these systems, existence of nonstoichiometric phases, and environment-dependent reactivity. 11 , 12 Several recent computational investigations have focused on the static properties of these systems, including the electronic structure and geometry in the gas phase. 13 − 16 Other studies utilized nonreactive interatomic potentials and provided important details of their structural properties and the associated bulk phases.…”

“…Despite the widespread applications of iron–sulfur clusters, controversy remains regarding their structure and stability in aqueous environments . Some of the difficulties are due to the complicated electronic structure of these systems, existence of nonstoichiometric phases, and environment-dependent reactivity. , Several recent computational investigations have focused on the static properties of these systems, including the electronic structure and geometry in the gas phase. − Other studies utilized nonreactive interatomic potentials and provided important details of their structural properties and the associated bulk phases . However, analysis of the dynamic nature of the clusters, or the effects of a surrounding aqueous environment, is scarce and limited to ab initio approaches. , …”