Polymeric gel for surface decontamination of long-lived gamma and beta-emitting radionuclides.

Synthesis and characterization of strippable polymeric-gel solution based on a water-soluble polymer (PVA), plasticizing agent (glycerol), and chelating agent (8-Hydroxyquinoline) for the surface decontamination from 137Cs and 60Co was carried out. Decontamination of glass and PVC surfaces was investigated in the present study, as a function of various chelating agents, gel-layer thickness, and radioactivity level. The decontamination efficiency was up to 95% for both radionuclides after 24 h of contact time with the contaminated surface. The obtained results suggest that the decontamination process of 137Cs and 60Co by polymer gel is possible combined by two mechanisms: chemically and physically.

Radiochemical signature of radium-isotopes and some radiological hazard parameters in TENORM waste associated with petroleum production: A review study.

Large amounts of TENORM waste (produced water, scale, and sludge) are created in oilfields around the world, presenting radiological risks to employees, the public, and the environment since activity concentrations of radioactive substances were above the exemption levels accredited by several authorities. Using the activity concentration of the radium-isotopes (226Ra and 228Ra) in the waste, we determined the 'fingerprint' as a radiochemical signature and some relevant 'radiological hazard parameters' in this review. The majority of the reported residues take the form of radio-contaminated (produced water, scale, and sludge) generated in Egypt's oilfields or elsewhere include radium isotope activity concentrations (226,228Ra) that exceed the international exemption limit. The activity concentrations of 226Ra(238U-series) in produced water, scale, and sludge waste were 0.04-1,480 Bq/L, 1.1-2,015,000 Bq/kg, and 1-120,800 Bq/kg, respectively, whereas 228Ra (232Th-series) was 0.34-250 Bq/L, 1.8-1,428,000 Bq/kg, and 10-122,830 Bq/kg, respectively. The radioactivities of radium isotopes were found to be above the exemption values recognized by WHO, IAEA, IOGP, EC, and ICRP in 95, 82, and 58% of produced water, scale, and sludge waste, respectively. The 226Ra(238U)/228Ra(232Th) ratio, from the other hand, was estimated to be utilised as a 'radiochemical fingerprint', or signature in the reported TENORM residues. The radium isotopes ratio in produced water, scale, and sludge waste in Egypt's oilfields is 0.41-4.45 (av. 1.98 ± 1.37, coefficient of variation, COV %: ∼69%), 0.2-21.4 (av. 4.3 ± 4.7, ∼109%), and 1.4-52.2 (av. 9.6 ± 15.3, ∼159%), respectively. For produced water, scale, and sludge waste, the 226Ra/228Ra ratios are 0.12-9.1 (av. 1.43 ± 1.72, ∼120%), 0.2-159 (av. 7.78 ± 23.5, ∼302%), and 0.8-223.5 (av. 14.1 ± 45.4, ∼322%) in global oilfields. The radiological hazard parameters (Ig, Ia, E◦, EG, and ELCR) owing to radium isotopes or 222Rn in most scale and sludge residues, as well as a small percentage of produced water, are all over the allowed safe limits. Substantial differences in the radium isotopes ratio in the reported waste can be attributed to thier geological, chemical, physical, and/or operational constraints. However, from the different perspectives of remediation and/or radiation protection programs, these values can be employed as a guidance for organizations investing in oil and gas production.

Bentonite phosphate modified with nickel: Preparation, characterization, and application in the removal of 137Cs and 152+154Eu.

The present study concerns the sorption of 137Cs and 152+154Eu from low-level radioactive waste (LLW) by bentonite phosphate modified with nickel (BPN) sorbent material. BPN was synthesized using the precipitation method and characterized using various analytical techniques such as Fourier transform infrared (FT-IR), scanning electron microscope (SEM), X-ray fluorescence (XRF), and X-ray diffraction (XRD). The sorption data show that 90 min is enough time to reach equilibrium. The distribution coefficients of 137Cs and 152+154Eu were studied as a function of pH. The distribution coefficient Kd was 2122.2 mL g-1 and 1076.5 mL g-1 for 137Cs and 152+154Eu at pH 9 and 4. The adsorption capacity of BPN has values of 31.1 and 28.2 mg g-1 for 137Cs and 152+154Eu, respectively. The effect of interfering species shows that the rate of adsorption of 137Cs and 152+154Eu slightly decreases as the concentration of the interfering species increases. The investigation of BPN for removing 137Cs and 152+154Eu radionuclides was conducted using a real LLW sample. Results showed that the BPN is appropriate to remove 137Cs and 152+154Eu from liquid radioactive waste and can be considered a potential composite for the purification of effluent polluted with these radionuclides.

Examination of the parameters affecting of 222Rn emanation for some industrial and environmental samples using gamma-spectroscopy.

The present work aims to radiologically characterize five samples (monazite, zircon, scale waste originating from petroleum production, black sands and phosphate rocks) from different industrial applications and environments in the Egyptian territory. The first section of the present work discusses the measurement and analysis of 226Ra, 232Th and 40K concentrations. Moreover, the assessment of the hazard indices is given in terms of radium equivalent (Raeq), external hazard index (Hex), internal hazard index (Hin), gamma-activity index (Iγ) and alpha-activity index (Iα). The second section deliberates the 222Rn gas emanated from the samples and studies the physical parameters affecting the emanation process. The results found that the monazite sample has the highest concentration of 226Ra, 232Th and 40K; however, it reached 54435, 442105 and 583 Bq.kg-1, respectively, between the studied samples. Furthermore, black sands and phosphate rock samples exhibit the lowest concentration of 226Ra, 232Th and 40K. Results also show that the radon emanation coefficients decrease while the density of materials increases.

Purification of rad-waste arising from irradiated natural tin target towards tellurium-125m/antimony-125 radioisotope generator elaboration.

The present study introduces a new approach based on an irradiated tin target's impurity to produce a125Sb/125mTe radioisotope generator. A prepared generator gel matrix of zirconium-silico-tungstate was loaded with 6660 MBq (180 mCi) activity of the separated antimony. The loading and elution method has been studied as a function of the concentration of H2SO4 acid solution. The effect of mild oxidant (ascorbic acid) in the loading and complexing agent (acetic acid) in elution was investigated to improve the generator's elution profile. A mixture of (0.5 M) ascorbic acid and (0.5 M) H2SO4 acid solution as a loading solution resulted in a maximum distribution of 125Sb. In comparison, using (0.4 M) acetic acid as an eluent solution 125mTe yield reached 88.7% and minimised percentage of 125Sb breakthrough was obtained (<0.01%).

Preparation, characterization and application of Mg/Fe Hydrotalcite as gamma sealed source for spectroscopic measurements.

A feasibility study was conducted to prepare, characterize and apply Mg/Fe Hydrotalcite composite as a core material of γ-sealed source used in spectroscopic measurements. Co-precipitation method was used to prepare the composite. To understand and define the physicochemical properties of the prepared composite, different analytical techniques were used. Optimum conditions for the use of the prepared composite as a core material for a radioactive sealed source were obtained. Finally, radiometric analysis has been done, in addition to testing of both physical and mechanical properties for the prepared sealed source.

Evaluation of synthetic aluminum silicate modified by magnesia for the removal of 137Cs, 60Co and 152+154Eu from low-level radioactive waste.

The present study concerns the preparation, characterization and testing of an inorganic ion exchanger Aluminum Silicate Modified Magnesia (ASMM). The ASMM composite was prepared using sol-gel technique and characterized by XRD, XRF, FTIR, TGA, DTA, SEM and surface area analysis. The capability of the prepared composite for the removal of (Cs+, Co2+ and Eu3+) from aqueous solution was evaluated. Sorption studies were carried out taking into account important parameters such as (pH, initial concentration, contact time and temperature). Kinetic and isotherm models were applied to the prepared composite, kinetic data is well fitted with pseudo-second order kinetic model, Dubinin-Radushkevich isotherm model indicates that sorption was controlled by chemisorption process. The removal efficiency found to be 80% for Cs+, 90% for Co2+ and 95% for Eu3+.