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Study on the coordination structure of pt sorbed on bacterial cells using x-ray absorption fine structure spectroscopy.

Tanaka K, Watanabe N - PLoS ONE (2015)

Bottom Line: EXAFS spectra demonstrated that Pt sorbed on bacterial cells has a fourfold coordination of chlorine ions, similar to PtCl42-, which indicated that sorption on the protonated amine groups of the bacterial cells.This work clearly demonstrated the coordination structure of Pt sorbed on bacterial cells.The findings of this study will contribute to the understanding of Pt biosorption on biomass, and facilitate the development of recovery methods for rare metals using biosorbent materials.

View Article: PubMed Central - PubMed

Affiliation: Institute for Sustainable Sciences and Development, Hiroshima University, Higashi-Hiroshima, Japan.

ABSTRACT
Biosorption has been intensively investigated as a promising technology for the recovery of precious metals from solution. However, the detailed mechanism responsible for the biosorption of Pt on a biomass is not fully understood because of a lack of spectroscopic studies. We applied X-ray absorption fine structure spectroscopy to elucidate the coordination structure of Pt sorbed on bacterial cells. We examined the sorption of Pt(II) and Pt(IV) species on bacterial cells of Bacillus subtilis and Shewanella putrefaciens in NaCl solutions. X-ray absorption near-edge structure and extended X-ray absorption fine structure (EXAFS) of Pt-sorbed bacteria suggested that Pt(IV) was reduced to Pt(II) on the cell's surface, even in the absence of an organic material as an exogenous electron donor. EXAFS spectra demonstrated that Pt sorbed on bacterial cells has a fourfold coordination of chlorine ions, similar to PtCl42-, which indicated that sorption on the protonated amine groups of the bacterial cells. This work clearly demonstrated the coordination structure of Pt sorbed on bacterial cells. The findings of this study will contribute to the understanding of Pt biosorption on biomass, and facilitate the development of recovery methods for rare metals using biosorbent materials.

No MeSH data available.


Related in: MedlinePlus

(a) The k3-weighted χ(k) functions and (b) RSF values for Pt-sorbed bacterial cells of B. subtilis at pH 2: (i) Pt(II)-sorbed cell in 0.01 mol L-1 NaCl, (ii) Pt(II)-sorbed cell in 0.5 mol L-1 NaCl, (iii) Pt(IV)-sorbed cell in 0.01 mol L-1 NaCl, (iv) Pt(IV)-sorbed cell in 0.5 mol L-1 NaCl, (v) 1000 mg L-1 Pt(II) in 1 mol L-1 HCl, (vi) 1000 mg L-1 Pt(IV) in 1 mol L-1 HCl and (vii) Pt metal foil. The dashed lines indicate the fitted results obtained from an EXAFS simulation.
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pone.0127417.g004: (a) The k3-weighted χ(k) functions and (b) RSF values for Pt-sorbed bacterial cells of B. subtilis at pH 2: (i) Pt(II)-sorbed cell in 0.01 mol L-1 NaCl, (ii) Pt(II)-sorbed cell in 0.5 mol L-1 NaCl, (iii) Pt(IV)-sorbed cell in 0.01 mol L-1 NaCl, (iv) Pt(IV)-sorbed cell in 0.5 mol L-1 NaCl, (v) 1000 mg L-1 Pt(II) in 1 mol L-1 HCl, (vi) 1000 mg L-1 Pt(IV) in 1 mol L-1 HCl and (vii) Pt metal foil. The dashed lines indicate the fitted results obtained from an EXAFS simulation.

Mentions: The k3-weighted χ(k) function and RSF values for Pt-sorbed bacterial cells of B. subtilis and S. putrefaciens are shown in Figs 4 and 5, respectively. Plantinum(II) and Pt(IV) in a 1 mol L-1 HCl solution and Pt-sorbed bacterial samples both showed similar frequencies of the EXAFS oscillations in k-space (Figs 4a and 5a). The corresponding RSF values showed peaks occurring at R + ΔR = 1.95 Å (Figs 4b and 5b), which were attributed to the first shell of the chlorine atoms. The EXAFS spectra suggest that Pt sorbed on bacterial surface was coordinated by Cl ions, similar to PtCl42- and PtCl62-.


Study on the coordination structure of pt sorbed on bacterial cells using x-ray absorption fine structure spectroscopy.

Tanaka K, Watanabe N - PLoS ONE (2015)

(a) The k3-weighted χ(k) functions and (b) RSF values for Pt-sorbed bacterial cells of B. subtilis at pH 2: (i) Pt(II)-sorbed cell in 0.01 mol L-1 NaCl, (ii) Pt(II)-sorbed cell in 0.5 mol L-1 NaCl, (iii) Pt(IV)-sorbed cell in 0.01 mol L-1 NaCl, (iv) Pt(IV)-sorbed cell in 0.5 mol L-1 NaCl, (v) 1000 mg L-1 Pt(II) in 1 mol L-1 HCl, (vi) 1000 mg L-1 Pt(IV) in 1 mol L-1 HCl and (vii) Pt metal foil. The dashed lines indicate the fitted results obtained from an EXAFS simulation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440633&req=5

pone.0127417.g004: (a) The k3-weighted χ(k) functions and (b) RSF values for Pt-sorbed bacterial cells of B. subtilis at pH 2: (i) Pt(II)-sorbed cell in 0.01 mol L-1 NaCl, (ii) Pt(II)-sorbed cell in 0.5 mol L-1 NaCl, (iii) Pt(IV)-sorbed cell in 0.01 mol L-1 NaCl, (iv) Pt(IV)-sorbed cell in 0.5 mol L-1 NaCl, (v) 1000 mg L-1 Pt(II) in 1 mol L-1 HCl, (vi) 1000 mg L-1 Pt(IV) in 1 mol L-1 HCl and (vii) Pt metal foil. The dashed lines indicate the fitted results obtained from an EXAFS simulation.
Mentions: The k3-weighted χ(k) function and RSF values for Pt-sorbed bacterial cells of B. subtilis and S. putrefaciens are shown in Figs 4 and 5, respectively. Plantinum(II) and Pt(IV) in a 1 mol L-1 HCl solution and Pt-sorbed bacterial samples both showed similar frequencies of the EXAFS oscillations in k-space (Figs 4a and 5a). The corresponding RSF values showed peaks occurring at R + ΔR = 1.95 Å (Figs 4b and 5b), which were attributed to the first shell of the chlorine atoms. The EXAFS spectra suggest that Pt sorbed on bacterial surface was coordinated by Cl ions, similar to PtCl42- and PtCl62-.

Bottom Line: EXAFS spectra demonstrated that Pt sorbed on bacterial cells has a fourfold coordination of chlorine ions, similar to PtCl42-, which indicated that sorption on the protonated amine groups of the bacterial cells.This work clearly demonstrated the coordination structure of Pt sorbed on bacterial cells.The findings of this study will contribute to the understanding of Pt biosorption on biomass, and facilitate the development of recovery methods for rare metals using biosorbent materials.

View Article: PubMed Central - PubMed

Affiliation: Institute for Sustainable Sciences and Development, Hiroshima University, Higashi-Hiroshima, Japan.

ABSTRACT
Biosorption has been intensively investigated as a promising technology for the recovery of precious metals from solution. However, the detailed mechanism responsible for the biosorption of Pt on a biomass is not fully understood because of a lack of spectroscopic studies. We applied X-ray absorption fine structure spectroscopy to elucidate the coordination structure of Pt sorbed on bacterial cells. We examined the sorption of Pt(II) and Pt(IV) species on bacterial cells of Bacillus subtilis and Shewanella putrefaciens in NaCl solutions. X-ray absorption near-edge structure and extended X-ray absorption fine structure (EXAFS) of Pt-sorbed bacteria suggested that Pt(IV) was reduced to Pt(II) on the cell's surface, even in the absence of an organic material as an exogenous electron donor. EXAFS spectra demonstrated that Pt sorbed on bacterial cells has a fourfold coordination of chlorine ions, similar to PtCl42-, which indicated that sorption on the protonated amine groups of the bacterial cells. This work clearly demonstrated the coordination structure of Pt sorbed on bacterial cells. The findings of this study will contribute to the understanding of Pt biosorption on biomass, and facilitate the development of recovery methods for rare metals using biosorbent materials.

No MeSH data available.


Related in: MedlinePlus