title: Cyanobacteria as a biosorbent for mercuric ion.
abstract: The biosorption of Hg(2+) by two strains of cyanobacteria, Spirulina platensis and Aphanothece flocculosa, was studied under a batch stirred reaction system. Essential process parameters, including pH, biomass concentration, initial metal concentration, and presence of co-ions were shown to influence the Hg(2+) uptake. Hg(2+) uptake was optimal at pH 6.0 for both strains. The maximum loading capacities per gram of dry biomass were found to be 456 mg Hg(2+) for A. flocculosa and 428 mg Hg(2+) for S. platensis. At an initial concentration of 10 ppm Hg(2+), A. flocculosa was able to remove more than 98% of the mercury ion from solution. The biosorption kinetics of both strains showed that the metal uptake is bi-phasic, exhibiting a rapid initial uptake followed by a slower absorption process. The presence of dissolved Co(2+), Ni(2+), and Fe(3+) were found to play a synergistic role for Hg(2+) uptake by both strains. Regeneration of the biomass was examined by treating Hg(2+)-loaded samples with HCl and NH(4)Cl over four cycles of sorption and desorption.
authors.affiliation: Department of Chemistry, Iowa State University, Ames, IA 50011-3111, USA.
authors.forename: Amber
authors.initials: A
authors.lastname: Cain
authors.forename: Raveender
authors.initials: R
authors.lastname: Vannela
authors.forename: L Keith
authors.initials: LK
authors.lastname: Woo
mesh_terms: D000327:Adsorption; D000458:Cyanobacteria / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008628:Mercury / Q000737:chemistry*; D013045:Species Specificity; D013054:Spectrophotometry, Atomic
chemical_list: D008628:Mercury