A new method for mercury removal.
A method is described for the removal of mercury from solution by using the off-gas produced from aerobic cultures of Klebsiella pneumoniae M426. Cells growing in Hg-supplemented medium produced a black precipitate containing mercury and sulphur. The ratio of Hg:S was determined as approximately 1:1 by analysis using proton-induced X-ray emission, suggesting precipitation of HgS within the culture. The outlet gases produced by a mercury-unsupplemented aerated culture were bubbled into an external chamber supplemented with up to 10 mg HgCl(2)/ml. A yellowish-white precipitate formed, corresponding to 99% removal of the mercury from solution within 120 min. Energy dispersive X-ray microanalysis showed that this metal precipitate consisted of mercury, carbon and sulphur. Formation of mercury carbonate was discounted since similar precipitation occurred at pH 2 and no oxygen was detected in the solid, which gave an X-ray powder pattern suggesting an amorphous material, with no evidence of HgS. Precipitation of mercury with a volatile organosulphur compound is suggested. Bio-precipitation of heavy metals by using culture off-gas is a useful approach because it can be used with concentrated or physiologically incompatible solutions. Since the metal precipitate is kept separate from the bacterial biomass, it can be managed independently.
Essa
Ashraf M M
AM
School of Biosciences, The University of Birmingham, Edgbaston, B15 2TT, Birmingham, UK.
Macaskie
Lynne E
LE
Brown
Nigel L
NL
D000332:Aerobiosis / Q000502:physiology; D011232:Chemical Precipitation; D007711:Klebsiella pneumoniae / Q000254:growth & development*; D008628:Mercury / Q000378:metabolism*; D014873:Water Pollutants / Q000378:metabolism*; D018508:Water Purification / Q000379:methods
D014873:Water Pollutants; D008628:Mercury