Free and immobilized yeast for chromium trace preconcentration and wastewater clean up (remediation)

Inexpensive baker's yeast characterized as Saccharomyces cerevisiae was use d to selectively accumulate and preconcentrate Cr(III) from aqueous matrice s. The substrate was used in batch and continuous operation immobilized in the latter case on alginate. Several parameters affecting the degree of bio accumulation of Cr(III) and Cr(VI) were evaluated: pH, temperature, incubat ion amount of biomass, etc. In the presence of yeast, aqueous Cr(VI) remain s unaltered and in solution, while Cr(III) is quantitatively bound to the y east at pH 13. The experimental data were modelled using sorption isotherms and could be fitted to Langmuir-type expressions. By using the adsorbent S . cerevisiae immobilized on alginate, an adsorption-elution method was deve loped for or Cr(III) preconcentration based on retention on a column of imm obilized yeast and further evolution with 3 mL of 0.3 mol.L-1 HNO3. The sys tem developed was applied fur on-line remediation of wastewater samples tra ce chromium preconcentration in a certified river water sample.