Synergistic effects on gamma-ray shielding by novel light-weight nanocomposite materials of bentonite containing nano Bi2O3 additive

Abstract In recent years, nanocomposites have gained prominence as potential materials in the γ-radiation shielding and protection areas compared to other conventional materials. In view of this, the present study is devoted to fabricate new nanocomposites, based on raw bentonite clay (RB), as a natural, abundant and low-cost matrix. This was then intercalated with bismuth oxide nanoparticles (Bi2O3 NPs), as a non-toxic nano-additive for the formation of RB/(Bi2O3)x nanocomposites using Bi2O3(x) NPs + raw bentonite clay(1- x), where x = 0, 0.1, 0.2, 0.3 and 0.4 fractional weight. The pressing method at 200 bar was used to prepare nanocomposite disks with different compositions. Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed the successful preparation of various assembled nanocomposites. Moreover, the as-prepared nanocomposites as well as the Bi2O3 NPs were examined using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The SEM images confirmed that the Bi2O3 NPs were successfully incorporated into the bentonite clay layers and its average particle size was in the range 20.74–25.61 nm. Bulk density, effective porosity (%), and heaviness (H) were also determined by different nanofiller loading percentages. Measurements of the γ-ray shielding performance were studied and determined at various γ-ray photon energies emitted from various standard point sources of γ-rays (133Ba,137Cs and 60Co) using NaI(Tl) scintillation detector. Thus, some shielding parameters such as mass attenuation coefficients (μm), effective atomic number (Zeff) and effective electron density (Nel) were measured at 356.01, 662.66, 1173.23 keV, and 1332.50 keV. These parameters were also calculated theoretically by the XCOM simulation code. The results referred to good agreement between the theoretical and experimental values. It was confirmed that the γ-ray shielding properties were enhanced by increasing the loading percentage of Bi2O3 NPs. Therefore, the 40Bi nanocomposite specimen, containing 40.0 wt% Bi2O3 NPs, was characterized to exhibit the highest values of μm (0.1712 at 356.01 keV), Zeff (22.78 at 356.01 keV), and Nel (4.32 at 356.01 keV). It was concluded that adding Bi2O3 NPs to RB clay impacted vast improvements in γ-ray shielding properties. Such materials would be good candidates for use in construction and civil engineering, as well as in the fabrication of building materials used in medical and nuclear establishments.