The nitrogen-fixing cyanobacterium
Anabaena
sp. ATCC 33047, which generates substantial amounts of
exopolysaccharide, was immobilized by entrapment within
the reticulate network of polyurethane foam discs. The
immobilized
Anabaena sp. system has been investigated as
a potential biosorbent for the removal of cadmium from
aqueous solutions. The results showed that it was a highly
fast process, with 80 % of the adsorption taking place in
the first 10 min, reaching full equilibrium in about 50 min.
Data analysis indicated that the behaviour of the system
accurately fits to a monolayer adsorption model (Langmuir
isotherm). The maximal biosorption capacity determined
for the immobilized
Anabaena sp. system was as high as
162 mg Cd (II) per gram dry biomass. The outstanding
properties established for immobilized
Anabaena sp. in
polyurethane foam underline the relevance of such a system
as an alternative to current treatments of variety
effluents or wastewater contaminated with cadmium.
