Cadmium biosorption by cells of Spirulina platensis TISTR 8217 immobilized in alginate and silica gel

The biosorption of cadmium by immobilized Spirulina platensis on alginate gel and silica gel was studied. The maximum biosorption capacities for alginate immobilized cells and silica immobilized cells were 70.92 and 36.63 mg Cd/g biomass, respectively. Temperature did not have an influence on metal sorption, whereas an initial pH solution did. Sorption occurred in a wide pH range (pH 3-8). The highest adsorption of alginate immobilized cells was at pH 6, while silica immobilized cell adsorption was not affected at pH between 4 and 7. The immobilized cells were reused in consecutive adsorption-desorption. The results showed that immobilized cells could be repeatedly used in the sorption process up to five times.