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Title: Phosphate Imposed Limitations on Biological Reduction and Alteration of Ferrihydrite Mineralization

Abstract

Biogeochemical transformation (inclusive of dissolution) of iron (hydr)oxides resulting from dissimilatory reduction has a pronounced impact on the fate and transport of nutrients and contaminants in subsurface environments. Despite the reactivity noted for pristine (unreacted) minerals, iron (hydr)oxides within native environments will likely have a different reactivity owing in part to changes in surface composition. Accordingly, here we explore the impact of surface modifications induced by phosphate adsorption on ferrihydrite reduction by Shewanella putrefaciens under static and advective flow conditions. Alterations in surface reactivity induced by phosphate adsorption change the extent, nearly linearly, and pathway of iron biomineralization. Magnetite is the most appreciable mineralization product while minor amounts of vivianite and green rust-like phases are formed in systems having high aqueous concentrations of phosphate, ferrous iron, and biogenic bicarbonate. Goethite and lepidocrocite, characteristic biomineralization products at low ferrous-iron concentrations, are inhibited in the presence of adsorbed phosphate. Considering deviations in reactivity of iron (hydr)oxides with changes in surface composition is important for deciphering mineralization pathways under native conditions and predicting reactive characteristics.

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
903238
Report Number(s):
PNNL-SA-49207
16095; TRN: US200719%%518
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science & Technology, 41(1):166-172; Journal Volume: 41; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; IRON HYDROXIDES; IRON OXIDES; BIODEGRADATION; MINERALIZATION; PHOSPHATES; ENVIRONMENTAL TRANSPORT; CATALYTIC EFFECTS; Environmental Molecular Sciences Laboratory

Citation Formats

Borch, Thomas, Masue, Yoko, Kukkadapu, Ravi K., and Fendorf, Scott. Phosphate Imposed Limitations on Biological Reduction and Alteration of Ferrihydrite Mineralization. United States: N. p., 2007. Web.
Borch, Thomas, Masue, Yoko, Kukkadapu, Ravi K., & Fendorf, Scott. Phosphate Imposed Limitations on Biological Reduction and Alteration of Ferrihydrite Mineralization. United States.
Borch, Thomas, Masue, Yoko, Kukkadapu, Ravi K., and Fendorf, Scott. Mon . "Phosphate Imposed Limitations on Biological Reduction and Alteration of Ferrihydrite Mineralization". United States. doi:.
@article{osti_903238,
title = {Phosphate Imposed Limitations on Biological Reduction and Alteration of Ferrihydrite Mineralization},
author = {Borch, Thomas and Masue, Yoko and Kukkadapu, Ravi K. and Fendorf, Scott},
abstractNote = {Biogeochemical transformation (inclusive of dissolution) of iron (hydr)oxides resulting from dissimilatory reduction has a pronounced impact on the fate and transport of nutrients and contaminants in subsurface environments. Despite the reactivity noted for pristine (unreacted) minerals, iron (hydr)oxides within native environments will likely have a different reactivity owing in part to changes in surface composition. Accordingly, here we explore the impact of surface modifications induced by phosphate adsorption on ferrihydrite reduction by Shewanella putrefaciens under static and advective flow conditions. Alterations in surface reactivity induced by phosphate adsorption change the extent, nearly linearly, and pathway of iron biomineralization. Magnetite is the most appreciable mineralization product while minor amounts of vivianite and green rust-like phases are formed in systems having high aqueous concentrations of phosphate, ferrous iron, and biogenic bicarbonate. Goethite and lepidocrocite, characteristic biomineralization products at low ferrous-iron concentrations, are inhibited in the presence of adsorbed phosphate. Considering deviations in reactivity of iron (hydr)oxides with changes in surface composition is important for deciphering mineralization pathways under native conditions and predicting reactive characteristics.},
doi = {},
journal = {Environmental Science & Technology, 41(1):166-172},
number = 1,
volume = 41,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • No abstract prepared.
  • Secondary Mineralization Pathways Induced by Dissimilatory Iron Reduction of Ferrihydrite Under Advective Flow
  • Excessive phosphorus loss from soils poses a threat to surface-water quality. Soils comprise assemblages of multiple minerals, with Fe- and Al-oxides being important for phosphate sorption. Our objective was to measure reductive dissolution of an Fe-oxide and sorbed orthophosphate as affected by the presence of an Al-(hydr)oxide mineral. Aqueous suspensions containing 0.5 g ferrihydrite kg{sup -1} and up to 0.7 g boehmite kg{sup -1} and KH2PO4 added at 750 mmol kg{sup -1} of ferrihydrite were abiotically reduced at pH 6.0 for 72 h using 0.5% H2(g) in the presence of a Pt catalyst. A sharp decrease in zero-order Fe(II) dissolutionmore » rate coefficients was observed between 0 and 0.008 g kg{sup -1} of added boehmite, whereas net Fe(II) dissolution was essentially null for boehmite additions {ge} 0.02 g kg{sup -1}. Although net dissolution of PO{sub 4} occurred over time in the absence of boehmite, a net uptake occurred in the presence of boehmite. Auxiliary experiments suggested that Al(III) dissolved from boehmite decreased Fe(II) dissolution during reduction by sorbing to the ferrihydrite surface and blocking electron transfer. Because PO{sub 4} was taken up in excess of the maximum boehmite sorption capacity in systems with {le} 0.008 g boehmite kg{sup -1}, results suggested the formation of Al-phosphate or an Al(III)-PO{sub 4} complex on ferrihydrite surfaces. Phosphorus K-XANES spectroscopy of samples collected during reduction of a 1:1 ferrihydrite/boehmite mixture showed no consistent change in sorbed PO{sub 4} associated with Fe(III) versus Al(III).« less
  • The reductive biotransformation of 6-line ferrihydrite located within porous silica (intragrain ferrihydrite) by Shewanella oneidensis MR-1 was investigated and compared to the behavior of 6-line ferrihydrite in suspension (free ferrihydrite). The effect of buffer type (PIPES and NaHCO3), phosphate (P), and an electron shuttle (AQDS) on the extent of reduction and formation of Fe(II) secondary phases was investigated under anoxic conditions. Electron microscopy and micro X-ray diffraction were applied to evaluate the morphology and mineralogy of the biogenic precipitates and to study the distribution of microorganisms on the surface of porous silica after bioreduction. Kinetic reduction experiments with free andmore » intragrain ferrihydrite revealed contrasting behaviour with respect to the buffer and presence of P. The overall amount of intragrain ferrihydrite reduction was less than that of free ferrihydrite [at 5 mmol L-1 Fe(III)T]. Reductive mineralization was not observed in the intragrain ferrihydrite incubations without P, and all biogenic Fe(II) concentrated in the aqueous phase. Irrespective of buffer and AQDS addition, rosettes of Fe(II) phosphate of approximate 20-30 μm size were observed on porous silica when P was present. The rosettes grew not only on the silica surface but also within it, forming a coherent spherical structure. These precipitates were well colonized by microorganisms and contained extracellular materials at the end of incubation. Microbial extracellular polymeric substances may have adsorbed Fe(II) promoting Fe(II) phosphate nucleation with subsequent crystal growth proceeding in different directions from a common center.« less