s latimi - Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran
sh shayesteh far - Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran
a taheri - Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran

The removal of radium ions from aqueous solutions by C. indica alga has been studied in a batch system. The biosorption efficiency was determined as a function of pH, contact time and initial metal ions concentration. The results revealed that the uptake of radium ions by C. indica wasincreased by increasing the metal ion concentration and the contact time, where as it was decreased by decreasing pH of the solution. The maximum biosorption efficiency of C. indica was 83% for radium, respectively. Batch kinetic and isotherm of biosorption metal ions were investigated. The biosorption equilibrium was described by Langmuir and Freundlich isotherm models. It was shown that the equilibrium data could be better fitted by Freundlich equation. It was also found that the biosorption follows pseudo-second-order kinetic model.

Radium; Biosorption; C. indica; Kinetics; Adsorption isotherm