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Title: Effect of biofilm coatings at metal-oxide/water interfaces II: Competitive sorption between Pb(II) and Zn(II) at Shewanella oneidensis/metal-oxide/water interfaces

Competitive sorption of Pb(II) and Zn(II) on Shewanella oneidensis MR-1 biofilm-coated single-crystal α-Al 2O 3 (1 –1 0 2) and α-Fe 2O 3 (0 0 0 1) surfaces was investigated using long-period X-ray standing wave-florescence yield (LP-XSW-FY) spectroscopy. In situ partitioning of aqueous Pb(II) and Zn(II) between the biofilms and underlying metal-oxide substrates was probed following exposure of these complex interfaces to equi-molar Pb and Zn solutions (0.01 M NaNO 3 as background electrolyte, pH = 6.0, and 3-h equilibration time). At higher Pb and Zn concentrations (≥10 –5 M), more than 99% of these ions partitioned into the biofilms at S. oneidensis/α-Al 2O 3 (1 –1 0 2)/water interfaces, which is consistent with the partitioning behavior of both Pb(II) or Zn(II) in single-metal-ion experiments. Furthermore, no apparent competitive effects were found in this system at these relatively high metal-ion concentrations. However, at lower equi-molar concentrations (≤10 –6 M), Pb(II) and Zn(II) partitioning in the same system changed significantly compared to the single-metal-ion systems. The presence of Zn(II) decreased Pb(II) partitioning onto α-Al 2O 3 (1 –1 0 2) substantially (~52% to ~13% at 10 –7 M, and ~23% to ~5% at 10–6 M), whereas the presence of Pb(II) causedmore » more Zn(II) to partition onto α-Al 2O 3 (1 –1 0 2) surfaces (~15% to ~28% at 10 –7 M, and ~1% to ~7% at 10 –6 M) .The higher observed partitioning of Zn(II) (~28%) at the α-Al 2O 3 (1 –1 0 2) surfaces compared to Pb(II) (~13%) in the mixed-metal-ion systems at the lowest concentration (10 –7 M) suggests that Zn(II) is slightly favored over Pb(II) for sorption sites on α-Al 2O 3 (1 –1 0 2) surfaces under our experimental conditions.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1] ;  [6]
  1. Stanford Univ., Stanford, CA (United States)
  2. Stanford Univ., Stanford, CA (United States); Univ. of Paris, Paris (France)
  3. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
  4. Argonne National Lab. (ANL), Argonne, IL (United States)
  5. Univ. of Chicago, Chicago, IL (United States)
  6. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Geochimica et Cosmochimica Acta
Additional Journal Information:
Journal Volume: 188; Journal Issue: C; Journal ID: ISSN 0016-7037
Publisher:
The Geochemical Society; The Meteoritical Society
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 59 BASIC BIOLOGICAL SCIENCES; Shewanella oneidensis; biofilm; metal-oxide surface; competitive sorption; Pb; Zn; hematite; alumina; x-ray standing wave; LP-XSW-FY; metal partitioning
OSTI Identifier:
1340294