Abstract
The biosorption characteristics of Cd(II) ions using the NaCl-treated Ceratophyllum demersum were studied. The effect of
altering the conditions, such as solution pH, the biosorbent dosage and contact time for the biosorption of Cd(II), and the
biosorption/desorption studies, were investigated. Langmuir, Freundlich, Dubinin-Radushkevich and Redlich–Peterson models
were applied to describe the biosorption isotherms. Langmuir model fitted the equilibrium data better than the other isotherms
(R2=0.9903). The biosorption capacity of NaCl-treated C. demersum biomass for Cd(II) ions was found to be 35.71 mg g-1 at
optimum conditions of pH 6, biomass dosage of 4 g L-1 and contact time of 40 min. Evaluation of experimental data in terms of
biosorption kinetics showed that the biosorption of Cd(II) on NaCl-treated C. demersum followed pseudo-second order kinetics
well. Desorption data revealed that biosorption capacity of biomass did not decrease significantly after three
biosorption/desorption cycles.