Removal of Cs-137 from Real Liquid Radioactive Wastes Using Pumice in Fixed-Bed Column

Decontamination of the radiological pollutants takes a flagship role in the environmental restoration. It improves safety and minimizes the cost of the advanced activities. Therefore, this study was conducted to investigate the performance of pumice via a single-stage-fixed-bed column system to remove Cs-137 radionuclides from real liquid radioactive wastes (LRWs) and investigate the operation conditions affecting breakthrough occurrence. The pumice was pure, identified by a Fourier-transform infrared spectroscopy (FTIR), a scanning electron microscopy (SEM), a X-ray fluorescence spectrometry (XRF), and a X-ray diffraction (XRD) investigations. LRWs samples were radiologically characterized before and after decontamination by the gamma spectroscopy system with a high purity germanium (HPGe) detector. It is innovative and non-destructive test method. Results revealed that LRWs were contained a considerable concentrations of Cs-137 radioisotope. The maximum adsorption capacity was 106.47 kBq/g, which yielded at a bed depth of 0.2 cm, an influent discharge of 4 mL/min, a Cs-137 concentration of 19013.33 Bq/L, and a temperature of 20°C. The Thomas and the Clark models were appropriate for representing the data obtained from the experiments, because of their strong correlation factors 0.95 and 0.97, respectively. Results indicated that the adsorbed Cs-137 radionuclides increased with decreasing influent discharge and increasing radionuclides concentration. Based on the suitable models’ nature, the Cs-137 adsorption process was impulsive, happened on monolayer and heterogeneous surfaces, and was controlled by chemical interactions onto active pumice sites.