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
- Stanford Univ., Stanford, CA (United States)
- Stanford Univ., Stanford, CA (United States); Univ. of Paris, Paris (France)
- 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)
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Univ. of Chicago, Chicago, IL (United States)
- Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Competitive sorption of Pb(II) and Zn(II) on Shewanella oneidensis MR-1 biofilm-coated single-crystal α-Al2O3 (1 –1 0 2) and α-Fe2O3 (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 NaNO3 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-Al2O3 (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-Al2O3 (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) caused more Zn(II) to partition onto α-Al2O3 (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-Al2O3 (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-Al2O3 (1 –1 0 2) surfaces under our experimental conditions.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
- Grant/Contract Number:
- AC02-06CH11357; FG02-94ER14466
- OSTI ID:
- 1340294
- Alternate ID(s):
- OSTI ID: 1430545
- Journal Information:
- Geochimica et Cosmochimica Acta, Vol. 188, Issue C; ISSN 0016-7037
- Publisher:
- The Geochemical Society; The Meteoritical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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