Cr (III) recovery from Saccharomyces cerevisiae by elution : a preliminary study

To recover adsorbed metals from biosorbents, in order to recycle metal and reuse biomass in several adsorption/desorption cycles, elution conditions need to be optimized. The present work aimed to study the following elution parameters: eluant type and concentration (H2SO4, HNO3, HCl, CH3COOH and Na2CO3 0.1, 0.5 and 1.0 M, and EDTA 0.01, 0.05 and 0.1 M); biosorbent contact time with Cr (III) solution (15 min, 2 and 24 h), and S/L ratio (4 and 8 g/L). Experimental data show a decrease in Cr recovery efficiency with increasing sorption time, probably due to metal bioaccumulation. Concerning the S/L ratio, it was possible to observe, in most essays, that best recoveries were achieved using biosorbent concentration of 8 g/L. Comparing the eluants tested according to their metal recovery efficiencies, it can be concluded that Na2CO3 is not a good eluant (maximum recovery of 21 %). All the others showed equivalent behaviours, being necessary more assays to determine eluant treatment effect in Cr uptake capacity in subsequent sorption cycles.Fundação para a Ciência e a Tecnologia (FCT