Cyanobacteria as a Biosorbent for Mercuric Ion

Bioresour Technol. 2008 Sep;99(14):6578-86. doi: 10.1016/j.biortech.2007.11.034. Epub 2007 Dec 26.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Cyanobacteria / physiology*
  • Hydrogen-Ion Concentration
  • Kinetics
  • Mercury / chemistry*
  • Species Specificity
  • Spectrophotometry, Atomic

Substances

  • Mercury