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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.

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.

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).

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.

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...

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.

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.

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.

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.

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.

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.

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.