EQUILIBRIUM AND DYNAMIC MODELLING OF LEAD AND COPPER BIOSORPTION BY SPHAEROTILUS NATANS FREE CELLS IN BATCH AND MEMBRANE REACTORS

摘要

Application of biosorption (accumulation of pollutants onto non living biomasses) in waste water treatment is strictly related with the development and design of continuous processes. Conventional immobilisation procedures can be overcome by membrane reactors ensuring both a continuous separation and a good contact among free cells and polluted solutions. Continuous biosorption tests of single and binary metallic solutions (Cu, Pb) onto Sphaerotilus natans cells are performed by using UF/MF membrane reactors. The effect of metal competition (affinity order: Pb ＞ Cu) can be represented by dynamic modelling which also evidences the occurrence of a partial cell disruption (causing both the decline of permeate flow and the change of metal retention coefficient on the membrane). Dynamic simulations evidence that biosorption of multi-metallic systems in a series of membrane reactors is a potential solution for metal separation in the different stages according to the specific metal affinity order.