Cesium and cobalt radioactive isotopes (134Cs and 60Co) are dangerous to human health due to their long half-life about 2.1 and 5.3 year, respectively. Developing a new composite used as an efficient sorbent for these is an urgent requirement for radioactive waste management. Herein, preparation of different materials such as aluminum silicate (AS), cultured of Chlorella vulgaris (NCV) alga, and aluminum silicate/Chlorella vulgaris (AS/NCV) composite 3:1 were prepared by wet chemical technique and used to remove the 134Cs and 60Co radionuclides. Different analytical techniques were used to characterize the prepared sorbents as SEM, TEM, XRD, BET, TGA/DTA, FTIR particle size analyzer, and pore size distribution. The factors affecting the sorption process as pH, temperature, contact time, and weight of adsorbent were studied. The sorption process was found to follow a pseudo-second-order mechanism. The monolayer capacity for 134Cs radionuclide onto the aluminum silicate, non-living Chlorella vulgaris biomass, and aluminum silicate/Chlorella vulgaris composites are 66.67, 83.54, and 90.11 mg/g, respectively, and for 60Co radionuclide are 59.31, 91.99, and 99.24 mg/g, respectively. The values of thermodynamic parameters indicate that the sorption process is endothermic and spontaneous.
Keywords: Alga; Aluminum silicate; Chlorella vulgaris; Composite; Isotherm; Kinetics; Radionuclides; Sorption.