Batch adsorption treatment using Iraqi bentonite as a natural adsorbent was adopted in this study to decontaminate actual 137Cs radioactive wastewater from the Al-Tuwaitha Nuclear Research Center, located south of Baghdad. The bentonite characterization was applied before and after treatment, using chemical compositions analyses, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (BET) surface area analysis and Fourier-transform infrared spectroscopy (FT-IR). The batch adsorption mode was applied with the initial radioactivity concentration (1440.5 Bq/L), solid/liquid ratio (1 g/L), pH (6–8), contact time (1.5 h), and temperature (298°K). The adsorption experiments showed a decontamination removal efficiency of about 95.66% of 137Cs. A Freundlich adsorption isotherm model was approved for the adsorption of 137Cs, with a coefficient of determination R2 = 0.998. A pseudo-second-order model fitted well with the adsorption of 137Cs, with R2 = 0.983. The positive value of ΔH° in the thermodynamic results indicated that the adsorption process was endothermic physisorption (ΔH° = 15.01 kJ mol−1), spontaneous and favorable (ΔG° = −7.66 kJ mol−1 K−1), with a very low degree of disorder (ΔS° = 0.076 kJ mol−1 K−1).

The measurements of radioactive concentrations using portable radiological devices for radiochemistry laboratories at the Al-Tuwaitha nuclear site (section C) were studied, section C consists of three laboratories, C1, C2, and C3 were used, Redeye device to measure the radioactive concentrations of alpha and beta emitters, and the Interceptor™ Specifications device to detect radioisotopes. The results showed the presence of radioactive contamination in Unit C distributed over most of its parts. In the C1 laboratory, the highest radioactive contamination was recorded in HCL2 with a concentration of 113.65Bq/cm2. In addition, the C2 laboratory recorded the highest radioactive concentration in FH1 with a concentration of 830.14Bq/cm2 for Beta particle emitters, while the C3 laboratory recorded the highest pollution in FH contamination with a radioactive concentration of 75.26 Bq/cm2. The results show that location C shows the isotopes detected in the laboratory components, such as Cesium 137Cs, Neptunium 237Np, and Americium 241Am. The results showed the presence of contamination on the laboratory floor in the fourth part, contaminated with Americium 241Am and Lutetium 167Lu isotopes. While location B did not record radioactive contamination in most of its parts except for room B8 which recorded radioactive concentrations of about 1.33 Bq/cm2. While location A, that is, no radioactive contamination was recorded, and the readings were within the permissible limits