[Characterization and heavy metal adsorption properties of schwertmannite synthesized by bacterial oxidation of ferrous sulfate solutions].
An amorphous ferric hydroxysulfate named schwertmannite was synthesized by using bacterial oxidation of ferrous iron by resting A. ferrooxidans cells in acid ferrous sulfate solution (pH 2.5). The identification of the bacterially oxidized iron precipitate was carried out by SEM, XRD, FTIR and chemical analysis. Results showed that resting cells of A. ferrooxidans LX5 could completely oxidize ferrous ions to ferric ions in the FeSO4-H2O system after 2 days of incubation. The solution pH decreased from an initial 2.5 to 2.10, and about 15% of the ferrous iron was transformed into the red-brown precipitates. The subsequent characterization of the precipitates showed that the biotic, synthetic ferric hydroxysulfate was schwertmannite. Sorption edge measurement showed that the adsorption behavior of metal cations (e. g., Cu2+, Zn2+ and Cr3+) was pH-dependent. The adsorption increased with an increase in pH, and the maximum was found in a pH range of 6.0-7.0. For solution concentration of 50 mg x L(-1), the maximum adsorption efficiencies of Cu2+, Zn2+ and Cr3+ were 99.3%, 99.4% and 87.6%, respectively.
Zhou
Shun-gui
SG
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Zhou
Li-xiang
LX
Chen
Fu-xing
FX
D042763:Acidithiobacillus / Q000378:metabolism*; D005296:Ferrous Compounds / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D058085:Iron Compounds / Q000032:analysis* / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
D005296:Ferrous Compounds; D058085:Iron Compounds; D012996:Solutions; C511969:schwertmannite; C020748:ferrous sulfate