title: A new method for mercury removal.
abstract: 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.
authors.affiliation: School of Biosciences, The University of Birmingham, Edgbaston, B15 2TT, Birmingham, UK.
authors.forename: Ashraf M M
authors.initials: AM
authors.lastname: Essa
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Macaskie
authors.forename: Nigel L
authors.initials: NL
authors.lastname: Brown
mesh_terms: 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
chemical_list: D014873:Water Pollutants; D008628:Mercury