Synthesis and Application of MnO-Fe₂O₃ Nanocomposites for the Removal of ¹³⁷Cs and ⁶⁰Co Radionuclides from Artificial Radioactive Aqueous Waste

For innovative application in wastewater treatment techniques, MnO-Fe₂O₃ nanocomposites were successfully synthesized using the sol–gel auto-combustion method at different temperatures for the adsorption of ¹³⁷Cs and ⁶⁰Co radionuclides from aqueous solution. The characterization of these nanocomposites was carried out through FT-IR, SEM-EDX, and X-ray diffraction. These nanocomposites were employed as adsorbent materials for the removal of ¹³⁷Cs and ⁶⁰Co radionuclides from simulated radioactive waste solutions. The study involved a series of experiments aiming to demonstrate the MnO-Fe₂O₃ nanoparticles’ exceptional adsorption potential concerning ¹³⁷Cs and ⁶⁰Co. Additionally, the investigation delved into how variations in temperature, dose amount, contact time, and pH value influence the adsorption dynamics. Due to their high specific surface area, the synthesized MnO-Fe₂O₃ nanoparticles had high adsorption capacity of more than 60% and 90% for ¹³⁷Cs and ⁶⁰Co, respectively. By investigation of kinetics and adsorption isotherms, pseudo-second-order reaction and the Langmuir model turned out to fit well for the adsorption of ¹³⁷Cs and ⁶⁰Co onto the MnO-Fe₂O₃ nanocomposites. Moreover, a thermodynamic analysis revealed that the adsorption process was spontaneous for both target metals and the adsorption of ⁶⁰Co was endothermic, whereas the adsorption of ¹³⁷Cs was exothermic.