REMOVAL OF METAL IONS FROM SIMULATED WASTEWATER BY SACCHAROMYCES YEAST BIOMASS: COMBINING BIOSORPTION AND FLOTATION PROCESSES

Abstract

Aqueous solutions containing heavy metals can be successfully treated by a combination of biosorption and flotation, in order to remove (or recover) the contained metals. Nonliving biomass of yeast Saccharomyces, which is a solid industrial by-product, was found to be a suitable biosorbent of metal ions (zinc, copper, and nickel). It was found also possible to reuse it after the appropriate desorption treatment. Electrokinetic behavior of biomass as well as elution and multiple-cycles operation were investigated. The dispersed-air flotation technique, which was selected for generation of bubbles, was subsequently examined for solid/liquid separation, in order to harvest the metals-loaded biomass downstream. The main parameters affecting the flotation process were studied, such as the solution pH, the concentration of flotation collector (surfactant), the preliminary biomass modification, and the biomass concentration. The biosorptive flotation method was found promising for remediation applications of wastewaters containing toxic metals.

Keywords:

• Biosorption
• Toxic metals removal
• Flotation
• Yeast
• Biomass

ACKNOWLEDGMENTS

This research has been funded by the Environment and Climate EU research program (ENV94-CT95-0068, acronym Bioelecdetox). Thanks are due to the coordinator of the project Dr. Ian Hancock (Dept. of Microbiology, The University of Newcastle-upon-Tyne, U.K.) and to Ms. H. Roussou, Chemist, for help with the experimental part.