24 results on '"E. M. El Afifi"'
Search Results
2. Development of a radiochemical method for extraction chromatographic separation of Pb and Bi radioisotopes of forensic and environmental interest
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H. E. Rizk, E. M. El Afifi, and Mohamed F. Attallah
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Chemical separation ,Chromatographic separation ,Chromatography ,Chemistry ,Extraction (chemistry) ,010501 environmental sciences ,Physical and Theoretical Chemistry ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Natural radioactivity ,0104 chemical sciences ,0105 earth and related environmental sciences - Abstract
This work describes the purification and separation of some radionuclides of 210Pb and/or 210Bi that might be used in calibration of nuclear spectroscopic instruments for forensic purposes and environmental studies. The retention and desorption investigations have been done by Dowex HCR-S/S resin as the cationic exchanger by batch mode. Full retention of metal ions was achieved in 0.1 M HNO3 solution after an equilibration period of 2 h at room temperature. The uptake of Pb and Bi is reached to more than 95 and 85%, respectively. Desorption studies by several reagents indicated that 1 M citric acid and ammonium acetate are efficient to elute and separate Bi and Pb. Taking into consideration all the above obtained results, column applications packed by the Dowex HCR-S/S resin were carried out to separate 214,210Pb and 214Bi radionuclides either in TENORM-concentrate or old certified reference of 226Ra solution. The column application results revealed that the recovery of Pb and Bi radionuclides was ∼93%. In the radiochemical part, the eluted Bi was impure due to presence of 23% Pb. In contrast, 70% of pure Pb was obtained. Thus, the radionuclides 210Pb can be recovered from several waste resources by this method. It can be concluded that the Dowex HCR resin can be an alternative economic material that could be used to produce 210Pb from the TENORM wastes generated from some strategic industries.
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- 2020
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3. Sorption and separation performance of certain natural radionuclides of environmental interest using silica/olive pomace nanocomposites
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Karam F. Allan, G. A. Dakroury, E. M. El Afifi, and Mohamed F. Attallah
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Radionuclide ,Nanocomposite ,Chemistry ,Health, Toxicology and Mutagenesis ,Batch method ,Public Health, Environmental and Occupational Health ,Pomace ,Sorption ,Pollution ,Analytical Chemistry ,Nuclear Energy and Engineering ,Chemical engineering ,Radiology, Nuclear Medicine and imaging ,Spectroscopy - Abstract
This study is concerned with the sorption behavior of natural radionuclides (226Ra, 210Po, 228Th—originated from TENORM waste associated with petroleum industry) onto silica/olive pomace nanocomposite. Initially, nanocomposites of extracted silica and olive pomace are prepared and characterized by physicochemical techniques. In the batch technique, 60% SiO2 40% olive pomace (AM3) nanocomposite showed a considerable group sorption for 226Ra and 210Po larger than 228Th in 1M HNO3 and HClO4 solutions. In case of sorption by the compacted disc, sorption of 226Ra was similar to batch method, sorption of 228Th increased slightly to ~ 17%, while sorption of 210Po was decreased to 77%. Thus, AM3 nanocomposite can be considered as an efficient nano-adsorbent for sorption and separation of Ra-isotopes and 210Po-radionuclides from 226Ra–210Po–228Th admixture associated with nuclear and non-nuclear industries.
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- 2020
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4. New approaches for efficient removal of some radionuclides and iron from rare earth liquor of monazite processing
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E. M. El Afifi, A. M. Shahr El-Din, and Emad H. Borai
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Lanthanide ,Potassium iodate ,Environmental Engineering ,Chemistry ,Potassium ,Radiochemistry ,Thorium ,chemistry.chemical_element ,010501 environmental sciences ,01 natural sciences ,Chloride ,Radium ,chemistry.chemical_compound ,Monazite ,medicine ,Environmental Chemistry ,General Agricultural and Biological Sciences ,Iodate ,0105 earth and related environmental sciences ,medicine.drug - Abstract
In this article, new two approaches (A and B) are created for the efficient removal of the technically enhanced radium isotopes (228Ra, 226Ra and 223Ra), long-lived radioisotope of lead (210Pb), thorium (Th4+) and iron (Fe3+) from the rare earth chloride (RECl3) liquor produced during the monazite processing. In the first approach ‘A,’ elimination of the undesired species is achieved using a synergistic admixture of sulfate–sulfide solution (SO42−/S2− admixture), while the second approach ‘B’ is performed using an iodate solution (IO3−) as a selective precipitating agent. The results indicated that 14% of radionuclides and Th(IV), 12% of Ln(III) and 40% of Fe(III) were removed from the RECl3 liquor at pH 3. In the first approach ‘A,’ the average percentage removal (%R) of all the undesired species reached ~ 96% using sulfate–sulfide admixture (0.058/0.04 mol/L). In the second approach ‘B,’ the average % R of all undesired species is improved and increased to ~ 99% using potassium iodate solution of 0.155 mol/L. Therefore, iodate solution is considered as an efficient and selective agent for the removal of Ra isotopes, 210Pb, Th(IV) and Fe(III) from RECl3 liquor without loss in Ln(III) at the optimized conditions. In this respect, promising results are obtained for the purification and production of Ln(III) using iodate solution or sulfate–sulfide admixture. Finally, the proposed two approaches are considered to be efficient not only to minimize the radiological human risks but also to eliminate the interfering of Th and Fe ions, to produce highly purified lanthanides from monazite ore.
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- 2019
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5. Purification of rare earth chloride liquor associated with high-grade monazite exploitation
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A. M. Shahr El-Din, Emad H. Borai, and E. M. El Afifi
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Radionuclide ,Chromate conversion coating ,Chemistry ,Health, Toxicology and Mutagenesis ,Radiochemistry ,Rare earth ,Public Health, Environmental and Occupational Health ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Pollution ,Chloride ,0104 chemical sciences ,Analytical Chemistry ,Nuclear Energy and Engineering ,Impurity ,Monazite ,medicine ,Radiology, Nuclear Medicine and imaging ,Spectroscopy ,medicine.drug - Abstract
Removal of the non-desired impurities (radionuclides, Th(IV) and Fe(III)) with Ln(III) in high-grade monazite was developed. The chromate solution and pH are the factors controlling removal of the non-desired impurities. At pH 3, removal of radionuclides and Fe(III) was 30 and 60%, respectively, whereas Th(IV) interfered with Ln(III) liquor. When liquor was treated by 0.23 M chromate solution at pH 3, ~ 98% of Th(IV) and Fe(III) was removed and ~ 70% of radionuclides was removed from Ln(III) liquor with loss ≤ 20% is low compared with a previous study. Thus, exploitation of valuable Ln(III) can be done safely using the optimized chromate solution.
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- 2018
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6. Efficient removal of iodine and chromium as anionic species from radioactive liquid waste using prepared iron oxide nanofibers
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Mohamed F. Attallah, E. M. El Afifi, and S. E. Rizk
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Health, Toxicology and Mutagenesis ,Iron oxide ,chemistry.chemical_element ,010501 environmental sciences ,Liquid waste ,010403 inorganic & nuclear chemistry ,Iodine ,01 natural sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Chromium ,Adsorption ,Radiology, Nuclear Medicine and imaging ,Spectroscopy ,0105 earth and related environmental sciences ,Aqueous solution ,Public Health, Environmental and Occupational Health ,Hematite ,Pollution ,0104 chemical sciences ,Nuclear Energy and Engineering ,chemistry ,Nanofiber ,visual_art ,visual_art.visual_art_medium ,Nuclear chemistry - Abstract
Three synthetic hematite (SH) materials as iron oxides nanofibers were prepared and applied for the removal of 51Cr and radioiodine (131I) as anions associated with nuclear industry technology. The results exhibited that 70% of Cr(VI) and 90% of 131I were removed from aqueous solution using the SH1 adsorbent. In acid solutions, R % of Cr(VI) increased to > 90% with the decrease in concentration till 0.05M, while the R % of 131I was 94 and 79% at HNO3 and HCl, respectively. It was concluded that SH1 nanofibers is promising and selective adsorbent for Cr(VI) and 131I removal from aqueous or acid solutions.
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- 2018
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7. Baseline evaluation for natural radioactivity level and radiological hazardous parameters associated with processing of high grade monazite
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Emad H. Borai, R.F. Aglan, E. M. El Afifi, A. M. Shahr El-Din, and Mohamed Abo-Aly
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chemistry.chemical_element ,Mineralogy ,010501 environmental sciences ,010403 inorganic & nuclear chemistry ,Toxicology ,01 natural sciences ,Radiation Monitoring ,Hazardous waste ,Humans ,0105 earth and related environmental sciences ,Radionuclide ,Waste management ,business.industry ,Thorium ,General Medicine ,Radiation Exposure ,Uranium ,Contamination ,0104 chemical sciences ,chemistry ,Gamma Rays ,Radiological weapon ,Monazite ,Environmental science ,Metals, Rare Earth ,Radiation protection ,business - Abstract
Egyptian monazite is a promising resource and investment attractive for production of valuable metals of industrial or nuclear interest such as rare earth elements (REEs), thorium (Th) and uranium (U). The study was focused to establish a baseline framework in viewpoint of radiation protection for the workers in production of REEs from high-grade monazite treated by sodium hydroxide (NaOH) solutions. Radiological hazard indices (cancer, gonadal and other risks) were evaluated, due to emissions (α-, β- and γ-radiations) of radium-isotopes (228Ra, 226Ra, 223Ra) and lead (210Pb). The values of the estimated radiological hazard indices were higher than the permissible safe limits, worldwide average and varied with those reported in other countries. It was found that more than 70% of radioactivity and radiological hazardous indices resulted from emissions of 228Ra, while the rest was attributed to 226Ra, 223Ra and 210Pb. Therefore, processing of the Egyptian monazite can cause a significant radiological impact on workers through external exposure from γ-radiations and/or internal exposure through inhalation or ingestion airborne contaminated by the radionuclides. Thus, the results recommended that protection rules could be considered to prevent the radiation hazards associated with the production of the REEs from the high grade monazite attacked by caustic method.
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- 2017
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8. Selective elimination of natural radionuclides during the processing of high grade monazite concentrates by caustic conversion method
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Emad H. Borai, E. M. El Afifi, and A. M. Shahr El-Din
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Ammonium sulfate ,General Chemical Engineering ,Sodium ,chemistry.chemical_element ,Sulfuric acid ,General Chemistry ,010501 environmental sciences ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Potassium sulfate ,Chloride ,0104 chemical sciences ,Separation process ,chemistry.chemical_compound ,chemistry ,Monazite ,medicine ,Potassium chromate ,0105 earth and related environmental sciences ,Nuclear chemistry ,medicine.drug - Abstract
This work is directed for removal of the nondesired species (228Ra, 226Ra, 223Ra, 210Pb, Th(IV) and Fe(III)) in the rare earth chloride (RECl3) liquor before separation of Ln(III). The different factors affecting elimination of radium-isotopes, lead (210Pb), Th(IV) and Fe(III) from the RECl3 liquor, have been investigated and optimized. The results indicated that the activity concentration of radionuclides in RECl3 liquor was above the safe limits required during the separation process of Ln(III). Adjustment of pH 3±0.1 leads to eliminate 14±1% of radionuclides and Th(IV), and 40±3% of Fe(III), while 12±1% of Ln(III) was lost. The developed method shows that more than 95% of the nondesired species was selectively removed when the liquor was eliminated by potassium sulfate or sulfuric acid solutions in presence of Ba/Pb-carrier (1: 1). About 20-83% of Ln(III) was lost when the non-desired species removed by sodium or ammonium sulfate or potassium chromate solutions. Fe(III) interfered with Ln(III) when radionuclides and Th(IV) were eliminated by 2.6M H2SO4 in presence of Ba/Pb-carrier. Finally, use of 0.23M K2SO4 or 2.6M H2SO4 was efficient to reduce level of 228Ra, 226Ra, 223Ra and 210Pb to the safe limits in viewpoint of radiation protection. In addition, the interfered Th(IV) and Fe(III) were also eliminated efficiently from RECl3 liquor before the chemical processing of Ln(III).
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- 2017
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9. Correction to: Leachability of radium-226 from industrial phosphogypsum waste using some simulated natural environmental solutions
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M. Khalil, E. M. El Afifi, and Y. F. El-Aryan
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Global and Planetary Change ,Waste management ,Soil Science ,chemistry.chemical_element ,Geology ,Phosphogypsum ,Pollution ,Natural (archaeology) ,Radium ,chemistry ,Environmental engineering science ,Environmental Chemistry ,Environmental science ,Biogeosciences ,Earth-Surface Processes ,Water Science and Technology - Published
- 2019
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10. Leachability of radium-226 from industrial phosphogypsum waste using some simulated natural environmental solutions
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M. Khalil, E. M. El Afifi, and Y. F. El-Aryan
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Soil Science ,chemistry.chemical_element ,Phosphogypsum ,010501 environmental sciences ,engineering.material ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Rainwater harvesting ,Radium ,chemistry.chemical_compound ,Fertilizer industry ,Environmental Chemistry ,Sulfate ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Water Science and Technology ,Global and Planetary Change ,Geology ,Pollution ,0104 chemical sciences ,chemistry ,Environmental chemistry ,engineering ,Carbonate ,Fertilizer ,Leaching (metallurgy) - Abstract
This study investigated the leaching of radium-226 from phosphogypsum (PG) waste produced from the fertilizer industry by synthetic solutions that replicate water that may contact the waste in natural conditions. The results indicated that the activity concentration of Ra-226 in the PG was 461 ± 12 Bq kg−1 and compared with other studies carried out worldwide. The leached percentage of Ra-226 represents the exchangeable fraction loosely bounded in the matrix of the PG waste. The leached fraction of Ra-226 was 6.5 ± 0.6 and 9.0 ± 0.5% when the waste was exposed to rainwater and saline solution, respectively. It is also found that the leaching fraction increased 10–12 ± 0.4% when the waste was exposed to the admixture of saline solution containing Sr2+ or Ba2+ cations, whereas it was lowered to 4–5 ± 0.5% in the presence of carbonate or sulfate anions. When the PG is used as an economic fertilizer, the irrigation water can leach 7.8 ± 0.6% of Ra-226 that could contribute to plant uptake, thereby to animal and/or human consumption. The primary tests of the drinking water (well and tap resources) consumed by the populations surround the PG facility showed that the activity concentration of Ra-226 was below the minimum detectable activity.
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- 2018
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11. Synthesis and application of Poly(acrylamide-itaconic Acid)/Zirconium tungstate composite material for cesium removal from different solutions
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M. Holial, E. M. El Afifi, and K. F. Allan
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021110 strategic, defence & security studies ,Thermogravimetric analysis ,Materials science ,Scanning electron microscope ,General Chemical Engineering ,Composite number ,0211 other engineering and technologies ,Zirconium tungstate ,02 engineering and technology ,010403 inorganic & nuclear chemistry ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Adsorption ,chemistry ,Differential thermal analysis ,Itaconic acid ,Fourier transform infrared spectroscopy ,Composite material - Abstract
This study is conducted to find the conditions required to synthesize composite material for cesium (134Cs+) removal from the generated liquid waste associated with nuclear, medical, industrial, and/or research activities. The study shows that the optimum conditions required for synthesizing “Poly [acrylamide (AM)-itaconic acid (IA)]/N,N′-methylenediacrylamide (DAM)/Zirconium tungstate (ZrW)” or “Poly(AM-IA)/DAM/ZrW” are 0.01 g DAM dose as a cross-linker, a co-monomer concentration of 20%, a co-monomer composition (AM-IA) (12:88), and 0.03 g (melted at 450 °C–500 °C) ZrW with gamma irradiation dose of 30 kGy. The composite material was characterized by Fourier infrared (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscope (SEM), and Brunauer-Emmett-Teller (BET) surface area measurements. The adsorption performance of the composite was investigated. The maximum removal efficiency of 134Cs+ ions was found to be 93% in m...
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- 2015
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12. Investigation of some factors affecting on release of radon-222 from phosphogypsum waste associated with phosphate ore processing
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A.A. Nayl, E. M. El Afifi, and M.A. Hilal
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Health, Toxicology and Mutagenesis ,chemistry.chemical_element ,Mineralogy ,Radon ,Phosphogypsum ,Calcium Sulfate ,Mining ,Phosphates ,Radium ,Radiation Monitoring ,Soil Pollutants ,Environmental Chemistry ,Waste Management and Disposal ,Water content ,Strontium ,Moisture ,Phosphorus ,General Medicine ,Pollution ,Grain size ,chemistry ,Air Pollutants, Radioactive ,Environmental chemistry ,Environmental science ,Particle size - Abstract
The aim of this study is oriented to investigate the influence of some physicochemical factors such as radium distribution, grain size, moisture content and chemical constituents on releases of radon-222 from the accumulated phosphogypsum (PG) waste. The emanation fraction, activity concentration in the pore and the surface exhalation rate of radon-222 in the bulk PG waste are 34.5 ± 0.3%, 238.6 ± 7.8 kBq m(-3) and 213 ± 6.9 mBq m(-2) s(-1), respectively. These values were varied and enhanced slightly in the fine grain sizes (F1 0.125 mm) by a factor of 1.05 folds compared to the bulk residue. It was also found that release of radon from residue PG waste was controlled positively by radium (Ra-226), calcium (CaSO4) and strontium (SrO). About 67% of radon release attributed to the grain size below 0.5 mm, while 33% due to the large grain size above 0.5 mm. The emanation fraction of Rn-222 is increased with moisture content and the maximum emanation is ∼43% of moisture of 3-8%. It reduced slowly with the continuous increase in moisture till 20%. Due to PG waste in situ can be enhancing the background to the surround workers and/or public. Therefore, the environmental negative impacts due to release of Rn-222 can be minimized by legislation to restrict its civil uses, or increasing its moisture to ∼10%, or by the particle size separation of the fine fraction containing the high levels of Ra-226 followed by a suitable chemical treatment or disposal; whereas the low release amount can be diluted and used in cement industry, roads or dam construction.
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- 2015
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13. Removal of 226 Ra and 228 Ra from TENORM sludge waste using surfactants solutions
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Mostafa M. Hamed, Hisham F. Aly, E. M. El Afifi, and Mohamed F. Attallah
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Water Pollutants, Radioactive ,Chromatography ,Sewage ,Chemistry ,Health, Toxicology and Mutagenesis ,Extraction (chemistry) ,Cationic polymerization ,chemistry.chemical_element ,General Medicine ,Pollution ,Radium ,Surface-Active Agents ,chemistry.chemical_compound ,Radiation Monitoring ,Bromide ,Environmental Chemistry ,Waste Management and Disposal ,Nuclear chemistry - Abstract
The feasibility of using surfactants as extracting agent for the removal of radium species from TENORM sludge produced from petroleum industry is evaluated. In this investigation cationic and nonionic surfactants were used as extracting agents for the removal of radium radionuclides from the sludge waste. Two surfactants namely cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX100) were investigated as the extracting agents. Different parameters affecting the removal of both (226)Ra and (228)Ra by the two surfactants as well as their admixture were studied by the batch technique. These parameters include effect of shaking time, surfactants concentration and temperature as well as the effect of surfactants admixture. It was found that, higher solution temperature improves the removal efficiency of radium species. Combined extraction of nonionic and cationic surfactants produces synergistic effect in removal both (226)Ra and (228)Ra, where the removals reached 84% and 80% for (226)Ra and (228)Ra, respectively, were obtained using surfactants admixture.
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- 2015
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14. Remediation of TENORM scale waste generated from petroleum industry using single and mixed micelles solutions
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E. M. El Afifi, Mostafa M. Hamed, and Mohamed F. Attallah
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Radionuclide ,Waste management ,Environmental remediation ,chemistry.chemical_element ,Fraction (chemistry) ,02 engineering and technology ,Contamination ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Radium ,chemistry.chemical_compound ,Distilled water ,chemistry ,Bromide ,Materials Chemistry ,Environmental science ,Sewage treatment ,Physical and Theoretical Chemistry ,0210 nano-technology ,Spectroscopy - Abstract
Treatment of TENORM scale wastes generated from oil and gas production that contaminated by different radionuclides is an important societal, environmental, economical and technological challenge, due to the rise number of sites contaminated by these radionuclides. Bench-scale laboratory experiments were conducted to determine the removal characteristics of radium isotopes from TENORM-scale. This scale waste contained high level radioactivity (44,610 Bq/kg) due to the presence of radium isotopes (35,100 Bq/kg for 226Ra and 9510 Bq/kg for 228Ra). In this study, three different types of surfactants polyoxyethylene sorbitanmonooleate (Tween-80), cetyltrimethylammonium bromide (CTAB) and sodium-dodecylsulfate (SDS) as micelle-forming agents were used for treating scale wastes by separating the most contaminated fraction of the TENORM-scale for disposal. It is found that the highest efficiency of radium isotopes was about 52% and 55% for 226Ra and 228Ra, respectively using single micelles systems. Combined effect of mixed micelles produces synergistic effect in the remediation process, where the removals reached to about 80% for 226Ra and 228Ra were obtained using mixed micelles solutions. The scale-washing process water used in TENORM scale extractive washing is treated with conventional wastewater treatment technology or reused in successive washing for new scale waste. The results also point out that the treated water from the washing step was more effective compared to distilled water, probably due to surfactants contained in treated water. The data obtained in these studies may be considered as promising and efficient to treatment of TENORM scales economically.
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- 2019
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15. Sorption performance of light rare earth elements using zirconium titanate and polyacrylonitrile zirconium titanate ion exchangers
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M. Khalil, E. M. El Afifi, and Y. F. El-Aryan
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Lanthanide ,Aqueous solution ,Materials science ,Ion exchange ,General Chemical Engineering ,Inorganic chemistry ,Polyacrylonitrile ,chemistry.chemical_element ,Sorption ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Ion ,Samarium ,chemistry.chemical_compound ,Cerium ,chemistry ,TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY ,0210 nano-technology - Abstract
Lanthanum, cerium, neodymium, and samarium were sorption from aqueous solutions using zirconium titanate (ZrTi) and polyacrylonitrile zirconium titanate (PANZrTi) ion exchangers. The characterizations of prepared materials were performed using XRD, SEM, FTIR, TGA, and DTA techniques. The sorption behavior of various ions toward synthesized resin has been studied depending on reaction temperatures, pH values, and initial concentrations. The selectivity order found is Sm3+ > Nd3+ > Ce3+ > La3+ on ZrTi-100, Ce3+ > Sm3+ ≈ Nd3+ > La3+ on ZrTi-150, and Sm3+ ≈ Ce3+ > Nd3+ > La3+ on PANZrTi depending on the condition of prepared ZrTi samples. The Kd for lanthanide ions was slightly decreased with temperature increased, which indicated the exothermic nature. The sorption data obtained for equilibrium conditions have been analyzed using the different isotherm models, and the applicability of these isotherm equations was compared by the correlation coefficients, R2. It was established that the equilibrium isotherm models’ applicability follows the order: Langmuir > Dubinin– Radushkevich > Freundlich. It is found the Ce3+ has high adsorption capacity on each of ZrTi-100 and ZrTi-150, while Nd3+ has high adsorption capacity on PANZrTi.
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- 2017
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16. Comparative study on the radioactivity of TE-NORM in different components of oil separator tanks
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Nasser S. Awwad, Hisham F. Aly, Mohamed F. Attallah, and E. M. El Afifi
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Chromatography ,Waste management ,Chemical treatment ,Chemistry ,Separator (oil production) ,Physical and Theoretical Chemistry - Abstract
Natural radioactivity in the crude oil, produced water, sludge and scale wastes from the petroleum industry on the Suez gulf (Abu Redeis), Egypt were investigated. A low radioactivity was found in the produced water and crude oil samples. In the sludge waste samples, the levels of radioactivity were found to be 11.96 and 1.75 kBq kg−1 for Ra-226 (of U-series) and Ra-228 (of Th-series), respectively. In the scale waste samples, the levels of radioactivity were 11.7 and 4.2 kBq kg−1 for Ra-226 and Ra-228, respectively. Leaching of different radionuclides in the sludge and scale wastes was investigated using mineral acid alone or after treatment with certain carbonate solutions. The different parameters affecting the treatment were optimized. It is found that high removal of Ra-226 was achieved from sludge and scale wastes when pretreated with 10% sodium carbonate solution, followed by acid dissolution. Removal % of Ra-226 reached 77 and 87% from the sludge and scale wastes, respectively.
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- 2012
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17. Treatment of TENORM waste: Phosphogypsum produced in fertilizer industry
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S. A. El Reefy, Mohamed F. Attallah, E. M. El Afifi, and M.A. Hilal
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inorganic chemicals ,Radionuclide ,technology, industry, and agriculture ,Phosphogypsum ,Fractionation ,Pulp and paper industry ,Alkali metal ,complex mixtures ,chemistry.chemical_compound ,chemistry ,Nitric acid ,Particle size ,Leaching (metallurgy) ,Physical and Theoretical Chemistry ,Phosphoric acid - Abstract
This study concerns treatment of phosphogypsum (PG) waste from phosphoric acid production, containing 226Ra as major radioactive contaminant. Physical and chemical treatment was performed. The physical treatment was based on the particle size separation (dry and wet frationation), whereas the chemical treatment was carried out using leaching solutions (single and sequential leaching processes). The results showed that the particle size separation affected the distribution of radionuclides in PG waste. High enrichment fators (Q) of 226Ra and 210Pb were obtained in the wet fractionation. The Q value for 226Ra and 210Pb was 3.1 and 3.9 compared to the PG bulk. The chemical leaching conditions of PG waste were optimized. In the single chemical leaching, 40% of total radium-226 in PG was removed. In the sequential leaching, about 87% of 226Ra was removed when the PG waste was washed with alkali solutions and pretreated and leached with a nitric acid solution.
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- 2010
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18. Characterization of phosphogypsum wastes associated with phosphoric acid and fertilizers production
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M.A. Hilal, S.A. El-Reefy, Mohamed F. Attallah, and E. M. El Afifi
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Health, Toxicology and Mutagenesis ,chemistry.chemical_element ,Phosphogypsum ,Radon ,Fraction (chemistry) ,Calcium Sulfate ,Industrial waste ,chemistry.chemical_compound ,X-Ray Diffraction ,Radiation Monitoring ,Environmental Chemistry ,Phosphoric Acids ,Fertilizers ,Waste Management and Disposal ,Phosphoric acid ,Waste Products ,Radionuclide ,Isotopes of uranium ,Chemistry ,Radiochemistry ,Spectrometry, X-Ray Emission ,Phosphorus ,General Medicine ,Pollution ,Phosphorite ,Egypt ,Nuclear chemistry - Abstract
The present work is directed to characterize the phosphogypsum (PG) wastes associated with phosphoric acid produced by the wet process in industrial facility for the production of fertilizers and chemicals in Egypt. The PG waste samples were characterized in terms of spectroscopic analysis (X-ray diffraction, X-ray fluorescence, IR spectra) and radiometric analysis (gamma- and alpha-measurements). The gamma-ray measurements showed that the average activity concentrations are 140+/-12.6, 459+/-36.7, 323+/-28.4, 8.3+/-0.76 and 64.3+/-4.1 Bq/kg for U-238, Ra-226, Pb-210, Th-232 and K-40, respectively. The alpha-particle measurements of uranium isotopes showed that the average activity concentrations of U-238, U-235 and U-234 were 153+/-9.8, 7+/-0.38, 152+/-10.4 Bq/kg, respectively. The average radiochemical recovery (%) of the destructive alpha-particle measurements is approximately 70% with a resolution (FWHM) of approximately 30 keV. Activity ratios of U-238/Ra-226 and U-238/Pb-210 were less than unity (i.e.,1) and equal to 0.31+/-0.02 and 0.47+/-0.16, respectively. The isotopic ratios of U-238/U-235 and U-238/U-234 (in PG and PR samples) were close to the normal values of approximately 21.7 and approximately 1, respectively and are not affected by the wet processing of phosphate rock (PR). The obtained results of PG waste samples were compared with phosphate rock (PR) samples. The radiation hazard indices are namely, radium activity index (Ra-Eq370 Bq/kg), total absorbed gamma dose rate (D(gamma r)5 nGy/h) and radon emanation fraction (Rn-EF20%). Uncertainty of the sample counting was 95% confidence level of sigma. The results indicated the necessity to find suitable routes to decrease and/or redistribute the radionuclide of environmental interest (i.e., Ra-226) in PG wastes, consequently to reduce its radiation impacts in the surrounding environment.
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- 2009
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19. Sequential chemical treatment of radium species in TENORM waste sludge produced from oil and natural gas production
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Nasser S. Awwad, M.A. Hilal, and E. M. El Afifi
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Fossil Fuels ,Water Pollutants, Radioactive ,Environmental Engineering ,Health, Toxicology and Mutagenesis ,chemistry.chemical_element ,Sewage ,Waste Disposal, Fluid ,Water Purification ,Radium ,Environmental Chemistry ,Radiometry ,Waste Management and Disposal ,Radionuclide ,Models, Statistical ,Waste management ,Isotope ,Chemistry ,business.industry ,Radiochemistry ,Temperature ,Radioactive waste ,Hydrogen-Ion Concentration ,Pollution ,Refuse Disposal ,Oxygen ,Waste treatment ,Petroleum ,Leaching (metallurgy) ,business ,Oils ,Biotechnology ,Waste disposal - Abstract
This paper is dedicated to the treatment of sludge occurring in frame of the Egyptian produced from oil and gas production. The activity levels of three radium isotopes: Ra-226 (of U-series), Ra-228 and Ra-224 (of Th-series) in the solid TENORM waste (sludge) were first evaluated and followed by a sequential treatment for all radium species (fractions) presented in TENORM. The sequential treatment was carried out based on two approaches 'A' and 'B' using different chemical solutions. The results obtained indicate that the activity levels of all radium isotopes (Ra-226, Ra-228 and Ra-224) of the environmental interest in the TENORM waste sludge were elevated with regard to exemption levels established by IAEA [International Atomic Energy Agency (IAEA), International basic safety standards for the protection against ionizing radiation and for the safety of radiation sources. GOV/2715/Vienna, 1994]. Each approach of the sequential treatment was performed through four steps using different chemical solutions to reduce the activity concentration of radium in a large extent. Most of the leached radium was found as an oxidizable Ra species. The actual removal % leached using approach B was relatively efficient compared to A. It is observed that the actual removal percentages (%) of Ra-226, Ra-228 and Ra-224 using approach A are 78+/-2.8, 64.8+/-4.1 and 76.4+/-5.2%, respectively. Whereas in approach A, the overall removal % of Ra-226, Ra-228 and Ra-228 was increased to approximately 91+/-3.5, 87+/-4.1 and 90+/-6.2%, respectively.
- Published
- 2009
- Full Text
- View/download PDF
20. Subsequent separation and selective extraction of thorium (IV), Iron (III), Zirconium (IV) and Cerium (III) from aqueous sulfate medium
- Author
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R.F. Aglan, Mohamed Abo-Aly, Emad H. Borai, A. M. Shahr El-Din, and E. M. El Afifi
- Subjects
Zirconium ,Aqueous solution ,Solvent extraction ,Cyanex 272 ,Chemistry ,Inorganic chemistry ,Extraction (chemistry) ,amines ,Aqueous two-phase system ,chemistry.chemical_element ,Thorium ,02 engineering and technology ,D2EHPA ,020501 mining & metallurgy ,chemistry.chemical_compound ,Cerium ,0205 materials engineering ,Sulfate ,Phosphoric acid ,Nuclear chemistry - Abstract
Regarding to their presence as an important constituent in some ores such as monazite, this work aims for selective solvent extraction of thorium (IV), zirconium (IV), iron (III) and cerium (III) from aqueous sulfate medium using different basic and acidic extractants. To elucidate the extractability of these elements, different effective parameters were studied such as contact time, pH value, extractant concentration and the diluents type. In a single element system, Th (IV) was extracted by the primary amines (octylamine and tert.octylamine) and the acidic extractnts [di-(2-ethylhexyl) phosphoric acid (D2EHPA) and (bis(2,4,4-trimethyl pentyl) phosphinic acid (Cyanex 272))]. Moreover, secondary amine (N-methylaniline) is effective for Fe (III) extraction while, the primary amines are suitable for Zr (IV) extraction. Ce (III) can be extracted with the primary amines and D2EHPA. In a mixed elements system, Th (IV) was extracted firstly with Cyanex 272 (65 %) atpH1 followed by the extraction of Fe(III) with N-methylaniline (95 %), then Zr (IV) was precipitated atpH2.5 (84 %) whileCe(III) remains in the final aqueous phase.
- Published
- 2016
21. Utilization of natural hematite as reactive barrier for immobilization of radionuclides from radioactive liquid waste
- Author
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Mohamed F. Attallah, Emad H. Borai, and E. M. El Afifi
- Subjects
Langmuir ,Water Pollutants, Radioactive ,Health, Toxicology and Mutagenesis ,chemistry.chemical_element ,Mineralogy ,010501 environmental sciences ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Ferric Compounds ,symbols.namesake ,Adsorption ,Europium ,Environmental Chemistry ,Freundlich equation ,Waste Management and Disposal ,Environmental Restoration and Remediation ,0105 earth and related environmental sciences ,Radioisotopes ,Langmuir adsorption model ,General Medicine ,Actinide ,Hematite ,Pollution ,0104 chemical sciences ,Thermogravimetry ,chemistry ,visual_art ,symbols ,visual_art.visual_art_medium ,Nuclear chemistry - Abstract
Potential utilization of hematite as a natural material for immobilization of long-lived radionuclides from radioactive liquid waste was investigated. Hematite ore has been characterized by different analytical tools such as Fourier transformer infrared (FTIR), X-ray fluorescence (XRF), powder X-ray diffraction (XRD), thermogravimetry (TG) and differential thermal (DT) analysis, scanning electron microscopy (SEM) and BET-surface area. In this study, europium was used as REEs(III) and as a homolog of Am(III)-isotopes (such as (241)Am of 432.6 y, (242m)Am of 141 y and (243)Am of 7370 y). Micro particles of the hematite ore were used for treatment of radioactive waste containing (152+154)Eu(III). The results indicated that 96% (4.1 × 10(4) Bq) of (152+154)Eu(III) was efficiently retained onto hematite ore. Kinetic experiments indicated that the processes could be simulated by a pseudo-second-order model and suggested that the process may be chemisorption in nature. The applicability of Langmuir, Freundlich and Temkin models was investigated. It was found that Langmuir isotherm exhibited the best fit with the experimental results. It can be concluded that hematite is an economic and efficient reactive barrier for immobilization of long-lived radio isotopes of actinides and REEs(III).
- Published
- 2015
22. Evaluation of U, Th, K and emanated radon in some NORM and TENORM samples
- Author
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E. M. El Afifi, S. M. Khalifa, M.A. Hilal, and Hisham F. Aly
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Radiation ,Radiochemistry ,chemistry.chemical_element ,Mineralogy ,Thorium ,Phosphogypsum ,Radon ,Uranium ,Radium ,Black sand ,chemistry ,Monazite ,Environmental science ,Instrumentation ,Zircon - Abstract
Activity concentrations of 226Ra (of U-series), 228Ra (of Th-series) and potassium (40K) in some heavy minerals and building materials were determined and evaluated in some selected heavy mineral sands and building materials. Three heavy mineral sands (monazite, zircon and black sand) of industrial interest were used. Building materials used here include phosphogypsum (PG) wastes, natural gypsum, ceramics, granite, marble, cement and iron slag wastes associated with iron and steel production. The measurements were carried out using γ -ray spectrometry. The activity concentrations varied widely depending on sample origin. The results indicated that the high activity levels, radium equivalent activity, absorbed-gamma dose rate and effective annual dose rate were found in monazite, zircon and PG wastes as compared to the other materials. The mean activity concentrations in monazite were 40580 ± 1370 , 182425 ± 9870 and 11300 ± 9570 Bq kg - 1 for 238U, 232Th and 40K, respectively. This activity is equivalent to 0.39, 5.1 and 4.5 wt% for uranium as U 3 O 8 , thorium as ThO 2 and potassium-40 as K 2 O , respectively. The radium equivalent activity, absorbed-gamma dose rate and effective annual dose rate in monazite were 3.0 × 10 5 Bq kg - 1 , 1.3 × 10 5 nGy h - 1 and 163 mSv yr - 1 , respectively. The emanation coefficient (EC) of 222Rn was less than 20%. The average Rn EC was 18% for cement samples and ∼ 14 % for granite and ceramic samples. It concluded that the Rosetta beach could be considered a valuable source for some metallurgical processes of industrial interest, but with special precautions. Most of the studied building materials can be used without restrictions except PG wastes, granite and ceramic.
- Published
- 2006
- Full Text
- View/download PDF
23. Assessment of the226Ra content and the222Rn emanation fraction of TE-NORM wastes at certain sites of petroleum and gas production in Egypt
- Author
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Hisham F. Aly, E. M. El Afifi, and S. M. Khalifa
- Subjects
Naturally occurring radioactive material ,Health, Toxicology and Mutagenesis ,Public Health, Environmental and Occupational Health ,chemistry.chemical_element ,Radon ,Mass spectrometry ,Pollution ,Analytical Chemistry ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,chemistry ,Environmental chemistry ,Activity concentration ,Petroleum ,Radiology, Nuclear Medicine and imaging ,Oil and gas production ,Spectroscopy - Abstract
The 222Rn emanation fraction (EF) released from the technically enhanced naturally occurring radioactive material (TE-NORM) wastes at certain sites of petroleum and gas production was determined. The samples were analyzed by γ-ray spectrometry to determine the activity concentration of the 226Ra content, of which the 222Rn emanation fraction was calculated. The results showed that the 222Rn emanation fraction differs in the oil and gas production sites and it is independent of the activity concentration of 226Ra.
- Published
- 2004
- Full Text
- View/download PDF
24. Characterization of the TE-NORM waste associated with oil and natural gas production in Abu Rudeis, Egypt
- Author
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Nasser S. Awwad and E. M. El Afifi
- Subjects
Health, Toxicology and Mutagenesis ,education ,chemistry.chemical_element ,Radon ,Fractionation ,Radiation Dosage ,Industrial waste ,Extraction and Processing Industry ,Radium ,X-Ray Diffraction ,Hazardous waste ,Radiation Monitoring ,Occupational Exposure ,Environmental Chemistry ,Humans ,Particle Size ,Waste Management and Disposal ,Radioisotopes ,Radionuclide ,Radiochemistry ,Radioactive waste ,Spectrometry, X-Ray Emission ,General Medicine ,Pollution ,Spectrometry, Gamma ,Petroleum ,chemistry ,Metals ,Radioactive Waste ,Egypt ,Enrichment factor ,Nuclear chemistry - Abstract
The present study was conducted to characterize the Technically Enhanced Naturally Occurring Radioactive Materials (TE-NORM) waste generated from oil and gas production. The waste was characterized by means of dry screening solid fractionation, X-ray analysis (XRF and XRD) and gamma-ray spectrometry. Sediment of the TE-NORM waste was fractionated into ten fractions with particle sizes varying from less than 100 microm to more than 3 mm. The results showed that the TE-NORM waste contains mainly radionuclides of the 238U, 235U and 232Th series. The mean activity concentrations of 226Ra (of U-series), 228Ra (of Th-series) and 40K in the waste samples before fractionation (i.e. 3 mm) were found to amount to 68.9, 24 and 1.3 Bq/g (dry weight), respectively. After dry fractionation, the activity concentrations were widely distributed and enriched in certain fractions. This represented a 1.48 and 1.82-fold enrichment of 226Ra and 228Ra, respectively, in fraction F8 (2.0-2.5 mm) over those in bulk TE-NORM waste samples. The activity ratios of 238U/226Ra, 210Pb/226Ra, 223Ra/226Ra and 228Ra/224Ra were calculated and evaluated. Activity of the most hazardous radionuclide 226Ra was found to be higher than the exemption levels established by IAEA [International Atomic Energy Agency, 1994. International Basic Safety Standards for the Protection against Ionizing Radiation and for the Safety of Radiation Sources. GOV/2715/94, Vienna]. The radium equivalent activity (Ra-eq), radon (222Rn) emanation coefficient (EC) and absorbed dose rate (Dgammar) were estimated and these are further discussed.
- Published
- 2004
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