Synthesis and Characterization of γ-MnO2-AgA Zeolite Nanocomposite and its Application for the Removal of Radioactive Strontium-90 (90Sr)

In this scientific research, for the first time, the removal of radioactive strontium-90 (90Sr) by γ-MnO2-AgA zeolite as a novel nanocomposite adsorbent was accomplished under different conditions such as pH, temperature, adsorbent amount and the contact time that are examined from drinking water of Ramsar city and monitored via Ultra Low-Level Liquid Scintillation Counting (LSC) technique. Prior to the reaction study, this composite was successfully prepared through three steps; first, NaA nanozeolite was prepared by the hydrothermal method. Then, silver ions (Ag+) were loaded in the NaA nanozeolite framework using ion exchange procedure and silver (Ι) nitrate solution as silver precursor for the preparation of the AgA nanozeolite. Finally, MnO2 nanoparticles (NPs) with 19.3 wt% were dispersed and deposited on the external surface of AgA nanozeolite through impregnation method for the preparation of γ-MnO2-AgA zeolite. The synthesized samples have been characterized and identified using Scanning electron microscopy-energy dispersive micro-analysis (SEM-EDX), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) techniques. The obtained results denoted that radioactive 90Sr was removed and adsorbed by γ-MnO2-AgA zeolite nanocomposite under optimized conditions including pH= 8.5, temperature (25°C) and adsorbent amount (1.5 g) after 6 h with a yield 93%. The minimum detectable activity (MDA) for 90Sr via LSC instrument was 6.92 mBq/Lit. The counting efficiency of LSC system was 78%. It has been emphasized that γ-MnO2-AgA zeolite nanocomposite has a high capacity and potential for the removal of radioactive 90Sr.