Biosorption of copper(II) on immobilised Synechocystis aquatilis

Synechocystis aquatilis was immobilized in Ca-alginate via entrapment. The plain alginate, and alive and heatinactivated immobilized algae beads were used for the sorption of Cu 2+ ions from aqueous solutions at 25 DGC. Kinetic studies showed a fast initial rate, followed by a slower biosorption one. Adsorption of Cu2+, on the biosorbents increased with increasing initial Cu 2+ ions level in the solution. The heat-inactivated alga preparation showed a higher biosorption capacity than the alive counterpart. The biosorption equilibrium was established approx.in 3 h, and the equilibrium was well-described by the Langmuir and Freundlich adsorption isotherms. The effect of pH was also investigated and the maximum adsorption of Cu 2+ ions on the biosorbents was obtained appros.at pH 5.6.