Biosorption of aqueous Pb(II) by a metabolically inactive industrial Klebsiella pneumoniae strain

Abstract

A microbial consortium which was obtained from lead contaminated soil at a battery recycling plant in South Africa was previously proved to be effective at removing approximately 50% of Pb(II) from solution within the first 3 h at 80 and 500 ppm Pb(II). Klebsiella pneumoniae was determined to be the dominant species responsible for Pb(II) bioprecipitation which was the main lead removal mechanism. In the current study, the purified K. pneumoniae was metabolically deactivated by drying and the resulting biomass tested for Pb(II) adsorption properties. Results demonstrated that the metabolically inactive K. pneumoniae biomass removed approximately 39% of a 100 ppm Pb(II) solution in 3h. pH measurements and FTIR spectroscopy indicated cation exchange of ?? + -ions for Pb(II) as well as adsorption interactions with functional groups (hydroxyl compound and amide) as being responsible for this removal. These results confirmed biosorption being responsible for the initial phase of Pb(II) removal which acts as a vehicle for concentrating Pb(II) on the surface of the bacteria before bioprecipitation takes place. These results provide further insights into the Pb(II) removal mechanisms involved in the Pb(II) bioremediation processes required for eventual scaling of these processes.