Residual biomass from a whiskey distillery was examined for its ability to function as a biosorbent for uranium. Biomass recovered and lyophilised exhibited a maximum biosorption capacity of 165-170 mg uranium/g dry weight biomass at 15°C. With a view towards the development of continuous or semi-continuous flow biosorption processes it was decided to immobilize the material by (1) cross-linking with formaldehyde and (2) introducing that material into alginate matrices. Crosslinking the recovered biomass resulted in the formation of a biosorbent preparation with a maximum biosorption capacity of 185-190 mg/g dry weight biomass at 15°C. Following immobilization of biomass in alginate matrices it was found that the total amount of uranium bound to the matrix did not change with increasing amounts of biomass immobilized. It was found however, that the proportion of uranium bound to the biomass within the alginate-biomass matrix increased with increasing biomass concentration. Further analysis of these preparations demonstrated that the alginate-biomass matrix had a maximum biosorption capacity of 220 mg uranium/g dry weight of the matrix, even at low concentrations of biomass.

Since it had previously been found that biomass derived from the thermotolerant ethanol-producing yeast strain Kluyveromyces marxianus IMB3 exhibited a relatively high af®nity for heavy metals it was decided to determine whether or not it might be capable of textile dye biosorption. To this end, biosorption isotherm analysis was carried out using the biomass together with commonlyused textile dyes including Remazol Black B, Remazol Turquoise Blue, Remazol Red, Remazol Golden Yellow and Cibacron Orange. Although the dyes Remazol Black B, Remazol Turquoise Blue and Remazol Red adhered to the Langmuir model, the remaining dyes failed to do so. The observed biosorption capacities at equilibrium dye concentrations of 100 mg/l were compared and it was found that the biomass exhibited a signi®cant af®nity for each dye. The potential use of this biosorptive material in the bioremediation of textile processing ef¯uents is discussed.

Biomass derived from the Old Bushmill's Distillery Co. Ltd., Northern Ireland was harvested and examined for its ability to function as a biosorbent for metals such as Cu, Zn, Fe, Pb and Ag. Binding studies were carried out using biosorption isotherm analysis. Although the material had previously been shown to be capable of ef®cient U biosorption, its af®nity for Cu, Zn, Fe was lower. However, binding studies with Pb demonstrated that it had a maximum biosorption capacity for that metal of 189 mg/ g dry weight of the biomass. In addition, the biomass exhibited a maximum biosorption capacity of 59 mg/g dry weight for Ag and this compared very favourably with previously quoted values for other industrial sources of Saccharomyces cerevisiae. On the basis of the biosorption isotherm analyses carried out in this study, preference for this series of metals by the biomass was found to be Pb > U > Ag > Zn ³ Fe > Cu.

A bisorption process using electric fields to facilitate contact between a sorbate and non-living biomass is described. The latter is enclosed within a semi-permeable membrane together with an electrode. The counter electrode is placed in the sorbate solution and an established potential across the electrodes facilitates electrokinetic movement of the sorbate to the biosorbant material.

No abstract