Radioactive Cs Research Articles

Biosorption of Cs (I): Utilization of an eco-friendly adsorbent Dry Cowdung Powder

Dry Cowdung Powder (DCP) – a green biosorbent, has been demonstrated for Cs(I) removal from aqueous media using radiotracer technique. 100 mesh DCP was added to Cs(I) carrier solution spiked with radioactive Cs-137. Parameters like pH, biosorbent dose, agitation speed, contact time, temperature and Cs(I) ion concentration were optimized. Industrial effluents or other polluted water bodies contain different salts in varying proportions. To analyse the effect of these salts on adsorption of Cs(I), various sodium, potassium and ammonium salts were used. DCP characteristics pre and post biosorption of Cs(I) was analysed with EDAX spectra. The investigation reports a successful Cs(I) metal removal by following the principles of green chemistry.

Effective removal of non-radioactive and radioactive cesium from wastewater generated by washing treatment of contaminated steel ash

The co-precipitation process plays a key role in the decontamination of radionuclides from low and intermediate levels of liquid waste. For that reason, the removal of Cs ions from waste solution by the co-precipitation method was carried out. A simulated liquid waste (133Cs) was prepared from a 0.1 M CsCl solution, while wastewater generated by washing steel ash served as a representative of radioactive cesium solution (137Cs). By co-precipitation, potassium ferrocyanide was applied for the adsorption of Cs ions, while nickel nitrate and iron sulfate were selected for supporting the precipitation. The amount of residual Cs ions in the CsCl solution after precipitation and filtration was determined by ICP-OES, while the radioactivity of 137Cs was measured using a gamma-ray spectrometer. After cesium removal, the amount of cesium appearing in both XRD and SEM-EDS was analyzed. The removal efficiency of 133Cs was 60.21% and 51.86% for nickel nitrate and iron sulfate, respectively. For the ash-washing solution, the removal efficiency of 137Cs was revealed to be more than 99.91% by both chemical agents. This implied that the co-precipitation process is an excellent strategy for the effective removal of radioactive cesium in waste solution treatment.

Distribution of Radioactive Cesium during Wild Boar Meat Processing

Wild boar meat containing radioactive cesium (Cs) of approximately 1,000 Bq/kg (134Cs+137Cs) was processed into bacon, sausage, and ham. To understand the concentration and quantity change of radioactive Cs, the processing factor (Pf) and food processing retention factor (Fr) were calculated. The radioactive Cs quantity in the meat did not reduce during smoking. The dehydration-related meat mass reduction during smoking without decrease of radioactive Cs led to Cs condensation in the bacon compared with the raw rib meat before processing, resulting in a Pf of 1.18. Soaking in liquid, such as pickling in liquid and desalting or boiling in water, effectively removed radioactive Cs by leakage into water. Therefore, the Fr value of the boiled ham produced from a loin meat block through three liquid-soaking processes was 0.27. The Pf value of the boiled ham was 0.30 due to meat block mass reduction after boiling as a result of dehydration, along with protein thermal denaturation-related muscle tissue shrinkage. The steamed ham Fr value was 0.53, because the removal of radioactive Cs was less efficient by steaming than by boiling. The Pf value of the steamed ham was 0.54, almost the same as the Fr value, because the mass decrease rate was the same as the radioactive Cs decrease rate by steaming. The Fr and the Pf values of the boiled sausage, whose processing did not include soaking in the pickling liquid, were 0.64 and 0.62, respectively. Steaming the sausage meat did not remove radioactive Cs during the dehydration-related mass reduction, leading to Fr and Pf values of 1.01 and 1.17, respectively. This study found that processing into boiled ham was the most effective measure for reducing radioactive Cs quantity and concentration in raw meat. Processing into bacon and steamed sausage showed no Cs quantity reduction, with the moisture loss resulting in Cs condensation compared with the raw material.

Plutonium mobilization from contaminated estuarine sediments, Esk Estuary (UK)

Since 1952, liquid radioactive effluent containing238-242Pu, 241Am, 237Np, 137Cs, and 99Tc has been released with authorization from the Sellafield nuclear complex (UK) into the Irish Sea. This represents the largest source of plutonium (Pu) discharged in all western Europe, with 276 kg having been released. In the Eastern Irish Sea, the majority of the transuranic activity has settled into an area of sediments (Mudpatch) located off the Cumbrian coast. Radionuclides from the Mudpatch have been re-dispersed via particulate transport in fine-grained estuarine and intertidal sediments to the North-East Irish Sea, including the intertidal saltmarsh located at the mouth of the Esk Estuary. Saltmarshes are highly dynamic systems which are vulnerable to external agents (sea level change, erosion, sediment supply, and freshwater inputs), and their stability remains uncertain under current sea level rise projections and possible increases in storm activity. In this work, we examined factors affecting Pu mobility in contaminated sediments collected from the Esk Estuary by conducting leaching experiments under both anoxic and oxic conditions. Leaching experiments were conducted over a 9-month period and were periodically sampled to determine solution phase Pu via multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS), and to measure redox indicators (Eh, pH and extractable Fe(II)). Microbial community composition was also characterized in the sediments, and at the beginning and end of the anoxic/oxic experiments. Results show that: 1) Pu leaching is about three times greater in solutions leached under anoxic conditions compared to oxic conditions, 2) the sediment slurry microbial communities shift as conditions change from anoxic to oxic, 3) Pu leaching is enhanced in the shallow sediments (0–10 cm depth), and 4) the magnitude of Pu leached from sediments is not correlated with total Pu, indicating that the biogeochemistry of sediment-associated Pu is spatially heterogeneous. These findings provide constraints on the stability of redox sensitive Pu in biogeochemically dynamic/transient environments on a timescale of months and suggests that anoxic conditions can enhance Pu mobility in estuarine systems.

Radioactive isotopes 40K, 137Cs, 226Ra, 228Ra, 234Th in algae supplements – Potential radiotoxicity of aquatic superfoods

Many food products are recommended to give health benefits. Thus algae superfoods consumption is growing worldwide, although quite a few studies have examined the quantities of radionuclides they contain and their potential effects on human health. The study presents radioactive 40K, 137Cs, 226Ra, 228Ra, and 234Th in algae supplements available worldwide for human consumption. Samples have been quantified by gamma-ray spectrometry and the activity concentrations (Bq/kg dw) ranged 0.23–0.65 (137Cs) followed by 1.76–10.7 (226Ra), 0.20–12.7 (228Ra), 11.6–24.2 (234Th), and 20.1–400 (40K). Also, the effective radiation doses from 40K, 137Cs, 226Ra, 228Ra, and 234Th decay ingested with analyzed algae supplements have been estimated. The highest annual effective dose reaching 15.1 µSv/year has been assessed for naturally occurring 226Ra in Chlorella vulgaris from Japan. The Fukushima Nuclear Power Plant has not significantly impacted the effective dose from 137Cs present in algal superfoods. Based on the study, the activity concentrations of radionuclides seem to be low, the naturally occurring radionuclides would give the highest effective doses, and the investigated algae supplements could be considered safe food.

Designer biochar with enhanced functionality for efficient removal of radioactive cesium and strontium from water

Radioactive elements released into the environment by accidental discharge constitute serious health hazards to humans and other organisms. In this study, three gasified biochars prepared from feedstock mixtures of wood, chicken manure, and food waste, and a KOH-activated biochar (40% food waste + 60% wood biochar (WFWK)) were used to remove cesium (Cs+) and strontium (Sr2+) ions from water. The physicochemical properties of the biochars before and after adsorbing Cs+ and Sr2+ were determined using X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, extended X-Ray absorption fine structure (EXAFS) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDX). The WFWK exhibited the highest adsorption capacity for Cs+ (62.7 mg/g) and Sr2+ (43.0 mg/g) among the biochars tested herein. The removal of radioactive 137Cs and 90Sr exceeded 80% and 47%, respectively, in the presence of competing ions like Na+ and Ca2+. The functional groups present in biochar, including –OH, –NH2, and –COOH, facilitated the adsorption of Cs+ and Sr2+. The Cs K-edge EXAFS spectra revealed that a single coordination shell was assigned to the Cs–O bonding at 3.11 Å, corresponding to an outer-sphere complex formed between Cs and the biochar. The designer biochar WFWK may be used as an effective adsorbent to treat radioactive 137Cs- and 90Sr-contaminated water generated during the operation of nuclear power plants and/or unintentional release, owing to the enrichment effect of the functional groups in biochar via alkaline activation.

Effects of borosilicate glass on pollucite crystallization and Cs+ immobilization in geopolymer materials

Since Fukushima nuclear power plant accident there have been many publications on immobilization of radioactive 137Cs in the crystalline structure of pollucite (CsAlSi2O6). In this article, we report a novel method where Cs-polluted soil (metakaolin) and a specially formulated borosilicate glass power are sintered together to form a pollucite-based glass crystalline materials. Fine pollucite crystals are uniformly distributed in the matrix of glass phase. This is equivalent to pollucite being encapsulated by the borosilicate glass and theoretically this should enhance the chemical durability. Extensive characterizations of this material with differential scanning calorimetry (DSC), r-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and electronic differential system (EDS) reveal optimum glass content and that the formation temperatures of pollucite in the glass matrix was as low as 900 ℃, which is significantly lower than those used in forming Cs-pollucite by conventional sintering methods. Test showed that the Cs+ leaching rate of sample with 20 wt% glass content was only 4.19×10–4 g·m–2·d–1, lower than the sample without glass addition almost by an order of magnitude. This study not only presents an improved technique for 137Cs immobilization but may also provide a methodology for immobilization of other potential radioactive species.

Biosorption of Cs (I): Utilization of an eco-friendly adsorbent Dry Cowdung Powder

Dry Cowdung Powder (DCP) – a green biosorbent, has been demonstrated for Cs(I) removal from aqueous media using radiotracer technique. 100 mesh DCP was added to Cs(I) carrier solution spiked with radioactive Cs-137. Parameters like pH, biosorbent dose, agitation speed, contact time, temperature and Cs(I) ion concentration were optimized. Industrial effluents or other polluted water bodies contain different salts in varying proportions. To analyse the effect of these salts on adsorption of Cs(I), various sodium, potassium and ammonium salts were used. DCP characteristics pre and post biosorption of Cs(I) was analysed with EDAX spectra. The investigation reports a successful Cs(I) metal removal by following the principles of green chemistry.

Application of solid waste as an adsorbent for capture of 137Cs, 85Sr and 131I from environmental water

ABSTRACT Caesium, strontium, and iodine radionuclides are produced from uranium fission and they are easily soluble in water through accidents or leakages, such as those occurred at Chernobyl, Three Mile Island, and Fukushima. Thus, developing an economical and effective process for removing these radioisotopes from real water is a progressively important issue. Hence, adsorption of 137Cs, 85Sr, and 131I radionuclides was achieved using a solid waste adsorbent. The solid waste adsorbent is granular activated carbon (GAC) gained from the wasted household water filters. The gained data illustrated that the percentages of uptake for 137Cs, 85Sr, and 131I were 87.6, 85.6, and 82.7%, respectively. Application of GAC for the decontamination of real water as groundwater, river water, tap water, and seawater was achieved. The findings revealed that GAC has the ability to be employed effectively as a hopeful material for the decontamination of radioactive 137Cs, 85Sr, and 131I from the environmental water.

Cesium removal from wastewater: High-efficient and reusable adsorbent K1.93Ti0.22Sn3S6.43

Efficient and quick removal of radioactive Cs+ from wastewater is significant for the safe use of nuclear energy and human health. A novel adsorbent K1.93Ti0.22Sn3S6.43 (KTSS) was developed for Cs+ removal from complex natural water systems. The working mechanism of KTSS for removing Cs+ was the synergistic effect of ion exchange and the Cs⋯S binding, which was proved by several characterization techniques. KTSS showed ultrafast kinetics for Cs+ adsorption within 1 min with a removal rate of 99%. Meanwhile, KTSS exhibited a higher adsorption capacity of 450.12 mg/g than many other adsorbents to remove Cs+ and possessed excellent chemical stability in a wide pH range of 3–12. Thanks to the natural affinity arising from the S2− ligands, KTSS displayed excellent selectivity for Cs+ even in different complex water systems. The separation factors between Cs+ and the coexisting ions of Na+, K+, Mg2+, Ca2+ were ranged from 408.61 to 7448.20. Fortunately, by eluting with NaNO3 the adsorbent could realize the green regeneration and cyclic utilization. Furthermore, it was found that KTSS had tremendous advantages in the removal of Cs+ in comparison with the other adsorbents. Consequently, it should be considered that KTSS obtained in this study has great potential in applying ultrafast and high-efficient removal of Cs+ from wastewater.

Removal of trace radioactive Cs+ by zirconium titanium phosphate: From bench-scale to pilot-scale

Removing trace radioactive 137Cs from aquatic system is still a challenge. Herein, Zirconium Titanium Phosphate (ZTP) was prepared and utilized for Cs removal from seawater. The structure and morphology of ZTP were systematically characterized. ZTP exhibited typical feature of tetravalent metal acid, and the surface was pocked with abundant hydroxyl groups which can reacted with H2O to form exchangeable protons. Bench-scale to pilot-scale adsorption was carried out to assess Cs removal capacity and rate. ZTP showed a good adsorption performance for Cs+ especially at trace concentration (500 ppb) and the removal rate in deionized water and seawater were 98.8 % and 83.9 %, respectively. Radioactive experiments were conducted to test the selective removal of 137Cs+ and the removal rates reached 98.3 %. Slurry-bed adsorption device was designed and used as the pilot-scale equipment. The removal rate was as high as 92.7 % after 12 cycles, indicated that ZTP is one of the promising adsorbents in industrial application. Pyridine adsorption IR spectra indicated that surface of ZTP was riddled with Brønsted and Lewis acid sites, and the protons at the Brønsted acid site exchanged with Cs+. This work will provide reference for the treatment of large-scale Cs-contaminated wastewater.

Research and design of a rapid nuclide recognition system

Due to possible nuclear accidents as a radioactive source loss as happened in Nanjing, China, there is demand for rapid identification of nuclides. This paper proposes a new recognition algorithm based on sequential Bayes that reduces the time required for that identification. A nuclide identification system was built by appropriate detector selection, electronic design, and software programming. Experiments show that the radioactive sources 137Cs (with an activity of 46500 Bq) and 60Co (with an activity of 39000 Bq) at a distance of 40 cm from the detection system can be distinguished rapidly within 3.0 and 4.1 s respectively with a detection rate reaching 100%.

Preparation of a GO/PB-modified nanofiltration membrane for removal of radioactive cesium and strontium from water

In this study, a novel modified nanofiltration (NF) membrane was fabricated to treat radionuclide-contaminated water by incorporation of Prussian blue (PB), graphene oxide (GO) and polyethylene glycol (PEG) into polysulfone (PSf) substrate. In this work, PB provided a large number of adsorption sites for the membrane, GO improved the Donnan effect of the polyamide (PA) layer by enhancing the negative charge, and PEG promoted the uniform dispersion of PB through interparticle electrostatic interaction and steric hindrance while increasing the adsorption sites on the surface of channels in the substrate by adjusting the pore structure. A conceptual model for the role of substrate in interfacial polymerization was then proposed. The modified membrane achieved efficient rejection of cesium (Cs+, 99.5%) and strontium (Sr2+, 97.5%). Its Cs+ rejection rate still remained high (about 96%) even in the treatment of natural surface water containing various inorganic salts and organic matters. What’s more, the modified membrane exhibited excellent stability in both strong acid solutions and long-term operation. Then, potassium chloride (KCl) solution was applied to regenerate the modified membrane, which achieved high generation rate as compared to traditional acid regenerants. The excellent filtration performance inferred that the novel GO/PB-modified NF membrane holds great application potential for the application of simultaneous removal of radioactive Cs+ and Sr2+ from contaminated water.

Pre-launch characterization of the spectrometer of Hard X-ray Imager (HXI) onboard the ASO-S mission

As one of the three payloads of the Advanced Space-based Solar Observatory (ASO-S), the pre-launch characterization of HXI includes the characterization of the collimator and the spectrometer. This article focuses on the pre-launch characterization of HXI's spectrometer, including detection efficiency, energy resolution, and energy to ADC channel (E-C) relationship. The detection efficiency characterization necessitates a sufficient number of calibrated energy points in the HXI observation energy range, with a refined measurement around the absorption edge of the lanthanum bromide crystal, and is calibrated with an X-ray beam. The characterization results are consistent with the simulations and show that the detection efficiency difference between detector modules is controlled within ±3%. Radioactive sources 133Ba and 137Cs are used to calibrate the energy resolution and E-C relationship. The characterization results show that all detector modules' energy resolutions are better than 26% at 32 keV, meeting the design specification. And their E-C relationships vary regularly with voltage. All of the characterization results indicate that the flight model of the HXI spectrometer meets the performance requirements and is capable of performing on-orbit observation activities.

Simulating the Potential Impacts of Nuclear Power Plant Accident for Northern Vietnam

The Fangchenggang nuclear power plant has been built very close to the Vietnam boundary. This is done to generate potential impacts for Northern Vietnam if nuclear power plant accident occurs. This study applied the Weather Research and Forecasting (WRF) model to construct the meteorological data at horizontal mesh resolution of 1 km as input for the FLEXible PARTicle dispersion model (FLEXPART). The assumption of the nuclear accident at Fangchenggang Power Plant is considered with setup parameter of the Fukushima accident. The results show a similar in simulating the 137Cs concentration from 03 out of 24 experiments configured with different parameterisation schemes of the WRF model. However, the dry and wet deposition of radioactive 137Cs are significantly different. It is especially illustrated that if the accident occurs, then almost all provinces in northern Vietnam are affected. The high concentration of radioactive pollutants may be intensively transported from Fangchenggang nuclear power plant to Vietnam under the domination of wind fields in the wintertime. The maximum values of the total effective dose rate could reach up to over 10 mSvh-1 of dose rate during 50 to 100 hours. Importantly, the maximum effective dose continues to be observed during 145 to 205 hours.

137Cs and 40K activity concentrations in edible wild mushrooms from China regions during the 2014–2016 period

Introduction. Contamination by radiocaesium of edible wild mushrooms after major nuclear accidents is a long-lasting process in some regions of the world. Following greater awareness of radioactive pollution in Asia, particularly after the Fukushima accident, this study investigated the radioactivity of 137Cs and 40K contamination in edible wild mushrooms in China.
 Study objects and methods. The objects of the research were edible wild mushrooms collected during 2014 to 2016, from the Inner Mongolian and Yunnan regions of China. To obtain an insight into any environmental impacts to distant regions of mainland Asia, the mushrooms were analyzed for 137Cs activity. In parallel, the natural activity of 40K was also determined and used to estimate the content of total K. The topsoil underneath the mushrooms was also investigated from a few sites in Bayanhushu in Inner Mongolia in 2015.
 Results and discussion. The results showed that in 4 to 6 mushrooming seasons after the accident, mushrooms from both regions were only slightly contaminated with 137Cs, which implied negligible consequences. The activity concentrations of 137Cs in dried caps and whole mushrooms in 63 of 70 lots from 26 locations were well below 20 Bq kg–1 dry weight. Two species (Lactarius hygrophoroides L. and Lactarius volemus L.), from Jiulongchi in Yuxi prefecture showed higher 137Cs activities, from 130 ± 5 to 210 ± 13 Bq kg–1 dw in the caps. 40K activities of mushrooms were around two- to three-fold higher. A composite sample of topsoil (0–10 cm layer) from the Bayanhushu site (altitude 920 m a.s.l.) in Inner Mongolia showed 137Cs activity concentration at a low level of 6.8 ± 0.7 Bq kg–1 dw, but it was relatively rich in potassium (40K of 595 ± 41 Bq kg–1 and total K of 17000 ± 1000 mg kg–1 dw).
 Conclusion. Wild mushrooms from the Yunnan and Inner Mongolia lands only slightly affected with radioactivity from artificial 137Cs. Lack of 134Cs showed negligible impact from Fukushima fallout. Ionizing radiation dose from 137Cs in potential meals was a fraction of 40K radioactivity. The associated dietary exposure to ionizing irradiation from 137Cs and 40K contained in mushrooms from the regions studied was considered negligible and low, respectively. Mushroom species examined in this study are a potentially good source of dietary potassium.

Removal of Trace Radioactive Cs+ by Zirconium Titanium Pyrophosphate: From Bench-Scale to Pilot-Scale

Removal of Trace Radioactive Cs+ by Zirconium Titanium Pyrophosphate: From Bench-Scale to Pilot-Scale

Накопичення 137Cs у суміші лучних трав на торфово-болотних ґрунтах зони Полісся у Рівненській області

The role and effectiveness of the combined action of various types of mineral fertilizers on the productivity of the agrocenosis and the accumulation of radionuclides by the phytomass of perennial grasses on peat-bog soil (Histic Gleysols) have been investigated. The research was carried out during 2011-2013. In a temporary field experiment with seeded perennial grasses (Dáctylis glomeráta, Bromopsis inermis, Phleum pratense) used for livestock feed. The aim of the research is to identify the features of the effect of radiological load on the quality of agricultural products in fertilized and non-fertilized areas by measuring the specific activity of radioactive 137Cs in the dry phytomass of collected herbs, the density of soil contamination and calculating the coefficients of the transfer of radionuclides from soil to pasture fodder. The activity of 137Cs in plants was determined by gamma spectrometer. The introduction of increased doses of potash (K120) and phosphorus fertilizers together with potash (P60 K120) was effective in reducing the activity of radiocaesium in the dry mass of feed. Over the three years of research on the variant with potash fertilizers, a decrease in 137Cs activity in the feed by an average of 2.9 times was recorded, and at the site of the combined application of potash and phosphate fertilizers – by 2.7 times compared with the control variant of the experiment (without fertilizers).

Electromagnetic-Ray Absorption Using B2O3-PbO-Na2O Glass Mixtures as Radiation Protection Shields

In this work, Lead Borate glass system doped with sodium is prepared and fabricated using the melt-quenching technique. The glasses are prepared based on the empirical formula of xPbO, (80-x) B2O3, 20Na2O (where x=0, 10, 20, 30, 40, and 50). The densities of the samples are measured with the Archimedes method by using Benzene as an immersion liquid. The radiation shielding parameters of the prepared glass samples have been measured experimentally and calculated theoretically. The experimental mass attenuation coefficients are obtained by using a shielded NaI(Tl) detector at photon energies 511, 662, and 1173 keV of the radioactive sources 22Na, 137Cs, and 60Co respectively, where collimators of aperture diameter 3 mm are used to ensure that the detector absorbs a narrow beam of gamma rays. The calculated mass attenuation coefficients (µm), half-value layer (HVL), mean free path (MFP), effective atomic number (Zeff), effective electron density (Neff), atomic cross-section (σa), electron cross-section (σe) radiation protection efficiency (RPE) are performed theoretically by using WinXCom and Phy-X/PSD computer programs in the energy range from 1 keV to 1 GeV. The calculated parameters of the investigated glasses have been compared with the measured experimental values

Carbon-based electroactive ion exchange materials: Ultrahigh removal efficiency and ion selectivity for rapid removal of Cs+ ions

Radioactive cesium (137Cs) ions exhibit high-energy gamma radiation and long half-life. When they enter water body, serious environmental problems and damage to the human body are always generated. Herein, an electroactive composite membrane was facilely prepared by uniformly deposition of nickel hexacyanoferrate (NiHCF) nanoparticles on the surface and inner wall of coal-based tubular carbon membrane (CTCM) for rapid and selective separation of Cs+ from wastewater. This NiHCF incorporated CTCM tube exhibited an extremely high removal rate (over 99.99%) over a long period. Meanwhile, it also demonstrated extreme Cs+ selectivities even in the solutions with high coexisting ion concentrations (e.g., Cs+:Na+ = 1:99, Cs+:K+ = 1:99). The rapid and selective Cs+ uptake/release should be attributed to the better dispersion of NiHCF nanoparticles with high selectivity to Cs+ in the CTCM tube, which reduced the mass transfer distance, increased fluid turbulence and accelerated mass transfer rate. It is expected that such a NiHCF incorporated CTCM tube could be a promising alternative of conventional materials for the separating of radioactive Cs+ ions.