Uptake Of Cs Research Articles

Removal of radiocesium from low level radioactive effluents by hexacyanoferrate loaded synthetic zeolite: laboratory to pilot plant scale demonstration

Abstract Present paper reports removal of radiocesium from low level waste using a modified sorbent (13X-CFC) prepared by in-situ precipitation of potassium copper hexacyanoferrate(II) inside the macropores of a synthetic zeolite. The Cs exchange isotherm of the sorbent is established and it found to follow Fruendlich absorption isotherm equation. It is varified that presence of hexacyanoferrate on zeolite facilitates rapid Cs uptake performance. This is further confirmed in laboratory scale column tests, wherein excellent Cs removal performance from low level waste simulant was observed even at higher flow rates (40 bed volumes per hour). The utility of the sorbent is established through successful demonstration in a pilot scale (50 L) trial with almost complete removal of 137Cs from more than 14,000 bed volumes of actual low level waste. The sorbent, owing to its low cost and excellent 137Cs removal performance, is expected to find application in treatment of very low active waste streams.

Застосування місцевих меліорантів на торфових грунтах та їх вплив на зменшення надходження 137Cs в рослини у вегетаційних дослідах

Застосування місцевих меліорантів на торфових грунтах та їх вплив на зменшення надходження 137Cs в рослини у вегетаційних дослідах

Stable cesium (133Cs) uptake by Calla palustris from different substrates

The uptake of stable cesium (133Cs) by Calla palustris was evaluated from four different substrates: water, soil, keramzit (a clay granule) and water with the addition of a potassium compound, after an eight days exposure to a solution of 0.5mM cesium chloride. Stable cesium was used because it is commonly supposed that its uptake by plants is the same of that of radiocesium (137Cs). The plants were differentiated in their parts (roots, healthy leaves, dead leaves and flowers) and analyzed with ICP-MS. The lowest average concentration of absorbed Cs was found in plants exposed in soil (0.7mg/kg, S.D.=96.8), while the highest in plants exposed in water (147mg/kg, S.D.=51.7). During the experiment the water planted plants removed 31.6% of provided Cs while those planted in soil removed only 0.06%. The addition of potassium to water was tested because of the competition effect that arises between these two elements: this effect was confirmed with the result that the average uptake in the presence of potassium was lower (41mg/kg in exposed plants, S.D.=76.1). The uptake was also lower in the solid-based substrates (soil and keramzit), because of the known tendency of Cs to bind with soil particles, thus becoming less available to plants. There was no evidence that the different parts of the plant showed different uptake effectiveness, or that the health of the plant (evaluated with a qualitative method) had any effect on the uptake of Cs.

Influence of soil types and osmotic pressure on growth and 137Cs accumulation in blackgram (Vigna mungo L.)

A pot experiment was conducted to study the effects of soil types and osmotic levels on growth and 137Cs accumulation in two blackgram varieties differing in salinity tolerance grown in Fukushima contaminated soils. The contamination levels of the sandy clay loam and clay soil were 1084 and 2046 Bq kg−1 DW, respectively. The 137Cs activity was higher in both plants grown on the sandy clay loam than on the clay soil regardless of soil 137Cs activity concentration. No significant differences were observed in all measured growth parameters between the two varieties under optimal water conditions for both types of soil. However, the growth, leaf water contents and 137Cs activity concentrations in both plants were lower in both soil types when there was water stress induced by addition of polyethylene glycol. Water stress-induced reduction in total leaf area and total biomass, in addition to leaf relative water content, were higher in salt sensitive ‘Mut Pe Khaing To’ than in salt tolerant ‘U-Taung-2’ plants for both soil types. Varietal difference in decreased 137Cs uptake under water stress was statically significant in the sandy clay loam soil, however, it was not in the clay soil. The transfer of 137Cs from soil to plants (i.e., root, stem and leaf) was higher for the sandy clay loam for both plants when compared with those of the clay soil. The decreased activity of 137Cs in the above ground samples (leaf and stem) in both plants in response to osmotic stress suggested that plant available 137Cs decreased when soil water is limited by osmotic stress.

Anchoring of CoHFC nanoparticles on clinoptilolite for remedy of nuclear wastes

To improve the mechanical properties, the cobalt ferrocyanide precipitation was carried out on clinoptilolite as an inorganic polymer. In this work the combination of two important factors, stability (zeolite) and high adsorption capacity (cobalt ferrocyanide) were considered to improve the ions uptake ability of adsorbent. The modification was approved by X-ray diffraction, Scanning electronic microscopy and Fourier transform infrared spectroscopy. The modified zeolite was applied to remove Sr(II) and Cs(I) ions from aqueous solution in a batch system. The adsorption capacities of modified zeolite for Cs(I) and Sr(II) improved to 90 and 130 mgg-1, respectively. The Sr(II) and Cs(I) removal were investigated as a function of shaking time, pH, Sr(II), and Cs(I) initial concentration and temperature. The experimental data were fitted well to Langmuir isotherm model for two sorbet metal ions. The time dependence sorption data showed that the uptakes of Cs(I) and Sr(II) were very rapid and apparent sorption equilibriums were achieved within 100 min of contact time. The kinetic experimental data were fitted to the pseudo-first order, pseudo-second order, the double exponential, Elovich and intraparticle diffusion models. The sorption rates and capacities as well as rate constants were evaluated.

Assessment of Cs and Sr accumulation in two epiphytic species of Tillandsia (Bromeliaceae) in vitro

ABSTRACTMultiple nuclides commonly occur together and exert toxicity simultaneously, but the difference between single and combined effects of the nuclides is rarely investigated. Epiphytic Tillandsia species are efficient air pollution biomonitors, but rarely used to monitor nuclide contamination. Two Tillandsia species, that is, T. brachycaulos and T. stricta, were chosen to test their capacity to accumulate Cs and Sr. Most plants were able to endure Cs and Sr stress for a long period, which suggested these species could resist toxic elements physiologically and metabolically. With the increasing Cs or Sr concentrations, nuclide contents in both species increased significantly, indicating the potential of Tillandsia species in monitoring nuclide pollutants. However, when the plants were treated with combined nuclides, the content of each ion decreased distinctly compared to those treated with single ion, which suggested Cs and Sr influenced and inhibited each other. In addition, T. brachycaulos seemed more efficient in the uptake of Sr, while T. stricta was more efficient for Cs. Both species accumulated more Sr than Cs at low concentrations, while more Cs than Sr at high concentrations. These results indicated that the uptake of Cs and Sr was related to both the concentrations of the nuclides and the plant species exposed.

Short day length-induced decrease of cesium uptake without altering potassium uptake manner in poplar.

Short day length-induced alteration of potassium (K) localization in perennial trees is believed to be a mechanism for surviving and adapting to severe winters. To investigate the relationship between cesium (Cs) and K localizations, a model tree poplar, hybrid aspen T89, was employed. Under short day length conditions, the amount of 137Cs absorbed through the root and translocated to the root was drastically reduced, but 42K was not. Potassium uptake from the rhizosphere is mediated mainly by KUP/HAK/KT and CNGC transporters. In poplar, however, these genes were constantly expressed under short-day conditions except for a slight increase in the expression a KUP/HAK/KT gene six weeks after the onset of the short-day treatment. These results indicated that the suppression of 137Cs uptake was triggered by short day length but not regulated by competitive Cs+ and K+ transport. We hypothesize that there are separately regulated Cs+ and K+ transport systems in poplar.

Turnover of 137Cs in ‘soil–tree’ system: An experience of measuring the isotope flows in a Siberian conifer forest

Little attention has been paid to the uptake of 137Cs in natural forests under low levels of the isotope fallout when no immediate ecological danger presents. Here we present the extended assessments of the soil-to-plant and canopy-to-litter flows of 137Cs recently evaluated in a native Siberian forested area. The area undergoes a typical after-fire long term succession, with light-conifer upper story being followed by undergrowth of Siberian fir and other dark-conifer species. The one-year-old needles of Siberian fir were found to accumulate the largest concentration of the isotope, 4.10 Bq/kg oven-dry weight during the first growth season, as compared with older needles that accumulated 4.67 Bq/kg oven-dry weight in 2–3 years of growth. Based on these data an approach was developed that, hypothetically, can allow one to estimate the 137Cs activity concentration in soil solutions. Direct activity measurements in the soil solutions were not possible. The isotope activity in soil solutions was estimated to be 0.0061–0.0105 Bq/L. Based on the original data from the litter fall the annual flow of the isotope from the upper canopy to on-ground litter was found to be 0.42–0.84 Bq/m2. The amount of 137Cs that returns yearly back from canopy with falling litter was estimated to be 0.012–0.015% of the total soil isotope content. A combination of the estimations obtained in our study with the values of global 137Cs fallout allowed us to assess the ages (the time of formation) of horizons of the soils in the area.

Radiocesium uptake, trophic transfer, and exposure in three estuarine fish with contrasting feeding habits

This study investigated the effects of different environmental factors on 137Cs uptake in three subtropical estuarine fish, and the trophic transfer of 137Cs in the fish from different preys. Our data showed that salinity, potassium, and temperature had appreciable effects on the dissolved uptake of 137Cs in the fish, but no conclusive relationship was found between the effects of salinity and potassium concentration on the uptake. The dietary assimilation of 137Cs was 51–55% in the omnivorous fish Siganus fuscescens when fed with macroalgae or bivalve tissues, and was much lower than those in carnivorous fish Sebastiscus marmoratus and Jarbua terapon (70–79%). Dietary pathway dominated the 137Cs accumulation in the omnivorous and carnivorous fish, both of which exhibited strong potential to biomagnify 137Cs from their preys. Using the biokinetic model, we demonstrated that salinity and temperature only had minor effects on the overall accumulation of 137Cs in carnivorous species living in estuarine environment. Modeling calculation suggested that it would take 37–80 days for the fish to reach 95% of steady-state concentration, and lower somatic growth increased the time to reach steady-state in the fish.

Analysis of the accumulation and redistribution patterns of cesium in Vicia faba grown on contaminated soils

The aim of this study was to investigate the relationship between cesium (Cs) contamination and plant growing stages in crops or vegetables grown on Cs-contaminated soils. Vicia faba was grown on Cs-contaminated soils under pot-culture conditions, and Cs uptake and bioaccumulation at various growing stages were then measured. The results showed that Cs uptake by V. faba was significantly greater on soils with a higher Cs content. As shown by the bioaccumulation factor (BCF), the highest transfer coefficient occurred when V. faba reached the maturation stage. Cs was easily transferred to young organs, especially seeds, with an average percentage of 9.60% in seeds during the maturation stage. This implies that Cs can be transferred to the human food chain at all growth stages of the plant, especially the last stages. Uptake rates of Cs remained stable during the generative growth phase of V. faba. This implies that the cultivation of varieties with short generative growth periods can reduce Cs accumulation in the edible parts of plants.

Minor Actinides Partitioning: Uptake of Palladium with Triazine-Containing Adsorbent under the Framework of SPMP Process

To remove Pd(II), a new triazine-containing silica adsorbent, BisDiOTP@SiO2–P, was prepared. The synthesis was achieved by impregnation in situ and immobilization of a multinitrogen ligand, BisDiOTP, into the pores of the SiO2–P support. The uptake of typical metals Sr(II), Pd(II), Li(I), Na(I), Cs(I), K(I), Rb(I), and Ba(II) onto BisDiOTP@SiO2–P was investigated. The effects of contact time and HNO3 concentration from 0.4 to 5.0 M were studied. The strong uptake ability and selectivity of BisDiOTP@SiO2–P for Pd(II) was indicated by six cycles of the batch uptake and desorption. The removal efficiency was always more than 99.2% for Pd(II) and less than 0.15% for others. In light of the results of batch experiments, the removal of Pd(II) from a simulated 1.0 M HNO3 was performed using BisDiOTP@SiO2–P as a stationary phase by extraction chromatography. Pd(II) adsorbed by BisDiOTP@SiO2–P was effectively desorbed with 0.2 M thiourea. An efficient removal of Pd(II) by BisDiOTP@SiO2–P was achieved. Some valuabl...

Adsorption of Cesium, Cobalt, and Lead onto a Synthetic Nano Manganese Oxide: Behavior and Mechanism

Synthesis parameters of nano manganese oxide (NMO) were tuned in order to maximize Cs and Co sorption efficiencies. The prepared oxide was characterized using various techniques including x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), SEM, and surface area analyzer. The sorption characteristics with respect to uptake of Cs, Co, and Pb were evaluated. An α − phase nano manganese oxide with a surface area of 165 m2 g−1 was synthesized. Maximum adsorption capacities were 230 mg g−1 for Pb2+, 73 mg g−1 for Cs+, and 26 mg g−1 for Co2+. The intra-particle diffusion was the rate-limiting step in the case of Pb2+, whereas both intra-particle diffusion and film diffusion contribute to the rate-determining step in the adsorption process in the case of Cs+ and Co2+. FT-IR analyses reveled that Cs+ and Co2+ coordinated to vacancy sites of NMO as inner-sphere complexes, while Pb2+ formed bidentate corner-sharing complexes. NMO had high affinity for Pb2+ but was also effective for sorption of Cs+ and Co2+ over a wide pH range, even in the presence of Na+. HCl (0.5 mol L−1) solution could regenerate the adsorbent successfully, and the NMO could be efficiently reused with lower production of residues. Thus, the prepared NMO can be efficiently used in wastewater treatment in terms of high adsorption capacity, easy availability, and low cost.

A comprehensive study on the uptake of dyes, Cu(II) and radioactive 137Cs(I) by sonochemically synthesized strontium/yttrium tungstate and molybdate nanoparticles

SrWO4, SrMoO4, Y2WO6 and Y2Mo3O12 nanoparticles has been synthesized via a facile sonochemical route. The samples obtained have been characterized using powder XRD and TEM. The surface area and surface charge of the nanoparticles have been determined from BET adsorption isotherm of N2 and zeta potential studies, respectively. Sorption characteristics of all the samples have been analyzed for cationic dye (Rhodamine B, Methylene blue), heavy metal Cu(II) ion and radioactive 137Cs(I) uptake. The effect of pH, concentration of dye and loading of sorbent on the process of adsorption has been analyzed. SrWO4 could be used for the selective removal of RhB from a mixture of RhB and MB dyes. The dye sorption process for all samples has been discussed using Langmuir and Freundlich models. Kinetic studies indicate that the adsorption behavior obey the pseudo second order rate law. The rate determining step has been elucidated from the Webber Morris and Boyd plots. Thermal regeneration of the dye loaded sorbents is easily possible and similar adsorption efficiency upto six consecutive cycles has been demonstrated. For the Cu(II)/Cs(I) loaded samples, pH variation leads to efficient regeneration of the sorbents. A comparative study on the uptake properties of all four sorbents for dyes and toxic heavy metal ions indicates that the efficiency of the sorption process depends on the surface charge as well the inherent crystal structures of the materials. It could be inferred that sonochemically synthesized Y2Mo3O12 nanoparticles exhibits superior sorption characteristics for uptake of dyes, heavy-metal ions like Cu(II) and radioactive 137Cs(I) ions.

Ring size dependent crown ether based mesoporous adsorbent for high cesium adsorption from wastewater

The work was designed for high cesium (Cs) adsorption from wastewater based on large ring size of dibenzo-30-crown-10-ether (DB30C10) immobilized mesoporous adsorbent. The Cs ion adsorption onto the mesoporous adsorbent from aqueous solution was investigated under the different experimental conditions such as reaction times, initial Cs ion concentrations, diverse competing ions and acidities. The Cs adsorption by mesoporous adsorbent was demonstrated at higher reaction rates than that of natural clay minerals. A superior correlation coefficient from the experimental and fitting values of the isotherm demonstrated that Cs ion adsorption on the mesoporous adsorbent was well fitted using the Langmuir isotherms model and exhibited the monolayer adsorption. The mesoporous adsorbent showed the high adsorption capacity as 107.16mg/g compared with the diverse crown ethers anchored adsorbent due to the large ring size of DB30C10 ligand. The effective surface area, adsorption capacity and encapsulation ability of mesoporous adsorbent were improved by the expanding ring size of DB30C10. The Cs adsorption by the mesoporous adsorbent was dependent on both pH and ionic strength of potassium (K) and sodium (Na). The presence of high amount K was adversely affected the Cs adsorption. On the other hand, the large amount of Na was slightly affected for Cs uptake. In addition, the adsorbent was reversible and kept remaining functionality after successful elution and regeneration using 0.25M HCl to reuse in multiple cycles without specific deterioration in its original performances. Hence, the newly large ring size based mesoporous adsorbent is a kind of potential and efficient material for high Cs adsorption from wastewater samples in Fukushima, Japan.

Bioaccumulation and retention kinetics of cesium in the Milkfish Chanos chanos from Jakarta Bay

Laboratory radiotracer experiments were conducted to study the uptake, assimilation, and retention of cesium (137Cs) in milkfish (Chanos chanos) from Jakarta Bay. In this study, we have examined the bioaccumulation and distribution of 137Cs in C. chanos obtained from 137Cs-labeled seawater and 137Cs-labeled Artemia sp. feeding. The uptake of 137Cs via seawater displayed a one-compartment model suggesting that the concentration factors of 137Cs within the milkfish (weight 2.46–9.86g) at a steady-state period were between 10.66 and 3.98mLg−1 after 10days of exposure. The depuration rate was observed to be low, with only 22.80–49.14% of 137Cs absorbed by C. chanos, which was absent 6days after exposure. By contrast, depuration occurred quickly for radiolabeled food uptake, reaching 20% of retention within 10days after exposure. Muscles and viscera of the milkfish exhibited the highest degree of end uptake and end depuration of 137Cs from seawater and feeding.

Genotypic difference in 137Cs accumulation and transfer from the contaminated field in Fukushima to azuki bean (Vigna angularis)

The screening of mini-core collection of azuki bean accessions (Vigna angularis (Willd.) Ohwi & Ohashi) for comparative uptake of 137Cs in their edible portions was done in field trials on land contaminated by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Ninety seven azuki bean accessions including their wild relatives from a Japanese gene bank, were grown in a field in the Fukushima prefecture, which is located approximately 51 km north of FDNPP. The contamination level of the soil was 3665 ± 480 Bq kg−1 dry weight (137Cs, average ± SD). The soil type comprised clay loam, where the sand: silt: clay proportion was 42:21:37.There was a significant varietal difference in the biomass production, radiocaesium accumulation and transfer factor (TF) of radiocaesium from the soil to edible portion. Under identical agricultural practice, the extent of 137Cs accumulation by seeds differed between the accessions by as much as 10-fold. Inter-varietal variation was expressed at the ratio of the maximum to minimum observed 137Cs transfer factor for seeds ranged from 0.092 to 0.009. The total biomass, time to flowering and maturity, and seed yield had negative relationship to 137Cs activity concentration in seeds. The results suggest that certain variety/varieties of azuki bean which accumulated less 137Cs in edible portion with preferable agronomic traits are suitable to reduce the 137Cs accumulation in food chain on contaminated land.

Influence of water management and fertilizer application on 137Cs and 133Cs uptake in paddy rice fields

Cesium-137 derived from the Tokyo Electric Power Company's Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident contaminated large areas of agricultural land in Eastern Japan. Previous studies before the accident have indicated that flooding enhances radiocesium uptake in rice fields. We investigated the influence of water management in combination with fertilizers on 137Cs concentrations in rice plants at two fields in southern Ibaraki Prefecture. Stable Cs (133Cs) in the plants was also determined as an analogue for predicting 137Cs behavior after long-term aging of soil 137Cs. The experimental periods comprised 3 y starting from 2012 in one field, and 2 y from 2013 in another field. These fields were divided into three water management sections: a long-flooding section without midsummer drainage, and medial-flooding, and short-flooding sections with one- or two-week midsummer drainage and earlier end of flooding than the long-flooding section. Six or four types of fertilizer subsections (most differing only in potassium application) were nested in each water management section. Generally, the long-flooding treatment led to higher 137Cs and 133Cs concentrations in both straw and brown rice than medial- and short-flooding treatments, although there were some notable exceptions in the first experimental year at each site. Effects of differing potassium fertilizer treatments were cumulative; the effects on 137Cs and 133Cs concentrations in rice plants were not obvious in 2012 and 2013, but in 2014, these concentrations were highest where potassium fertilizer had been absent and lowest where basal dressings of K had been tripled. The relationship between 137Cs and 133Cs in rice plants was not correlative in the first experimental year at each site, but correlation became evident in the subsequent year(s). This study demonstrates a novel finding that omitting midsummer drainage and/or delaying drainage during the grain-filling period enhances uptake of both 137Cs and 133Cs.

Growth and 137Cs uptake and accumulation among 56 Japanese cultivars of Brassica rapa, Brassica juncea and Brassica napus grown in a contaminated field in Fukushima: Effect of inoculation with a Bacillus pumilus strain

Fifty six local Japanese cultivars of Brassica rapa (40 cultivars), Brassica juncea (10 cultivars) and Brassica napus (6 cultivars) were assessed for variability in growth and 137Cs uptake and accumulation in association with a Bacillus pumilus strain. Field trial was conducted at a contaminated farmland in Nihonmatsu city, in Fukushima prefecture. Inoculation resulted in different responses of the cultivars in terms of growth and radiocesium uptake and accumulation. B. pumilus induced a significant increase in shoot dry weight in 12 cultivars that reached up to 40% in one B. rapa and three B. juncea cultivars. Differences in radiocesium uptake were observed between the cultivars of each Brassica species. Generally, inoculation resulted in a significant increase in 137Cs uptake in 22 cultivars, while in seven cultivars it was significantly decreased. Regardless of plant cultivar and bacterial inoculation, the transfer of 137Cs to the plant shoots (TF) varied by a factor of up to 5 and it ranged from to 0.011 to 0.054. Five inoculated cultivars, showed enhanced shoot dry weights and decreased 137Cs accumulations, among which two B. rapa cultivars named Bitamina and Nozawana had a significantly decreased 137Cs accumulation in their shoots. Such cultivars could be utilized to minimize the entry of radiocesium into the food chain; however, verifying the consistency of their radiocesium accumulation in other soils is strongly required. Moreover, the variations in growth and radiocesium accumulation, as influenced by Bacillus inoculation, could help selecting well grown inoculated Brassica cultivars with low radiocesium accumulation in their shoots.

Functionalized magnetic nanoparticles for the decontamination of water polluted with cesium

Magnetic nanoparticles are attracting considerable interest because of their potential applications in practically all fields of science and technology, including the removal of heavy metals from contaminated waters. It is, therefore, of great importance to adapt the surfaces of these nanoparticles according to the application. In this work advanced nanoparticles (NPs) with well-tailored surface functionalities were synthesized using the polyol method. The efficiency of a chelating agent, succinyl-β-cyclodextrin (SBCD), was first investigated spectrophotometrically and by Isothermal Titration Calorimetry (ITC). SBCD was then grafted onto nanoparticles previously functionalized with 3-aminopropyl triethoxsilane (NP-APTES). The resulting NP-SBCD system was then incubated with a solution of cesium. After magnetic separation, the solid residue was removed from the supernatant and characterized by X-Ray Photoelectron spectrometry (XPS), X-Ray Fluorescence spectrometry (XRF) and Superconducting QUantum Interference Device (SQUID) magnetometry. These characterizations show the presence of cesium in the solid residue, which indicates Cs uptake by the NP-SBCD system. This nanohybrid system constitutes a promising model for heavy metal decontamination.

Reduction-Induced Highly Selective Uptake of Cesium Ions by an Ionic Crystal Based on Silicododecamolybdate.

Cation adsorption and exchange has been an important topic in both basic and applied chemistry relevant to materials synthesis and chemical conversion, as well as purification and separation. Selective Cs(+) uptake from aqueous solutions is especially important because Cs(+) is expensive and is contained in radioactive wastes. However, the reported adsorbents incorporate Rb(+) as well as Cs(+) , and an adsorbent with high selectivity toward Cs(+) has not yet been reported. Highly selective uptake of Cs(+) by an ionic crystal (etpyH)2 [Cr3O(OOCH)6 (etpy)3]2 [α-SiMo12 O40 ]⋅3 H2O (etpy =4-ethylpyridine) is described. The compound incorporated up to 3.8 mol(Cs(+) ) mol(s)(-1) (where s=solid) by cation-exchange with etpyH(+) and reduction of silicododecamolybdate with ascorbic acid. The amount of Cs(+) uptake was comparable to that of Prussian blue, which is widely recognized as a good Cs(+) adsorbent. Moreover, other alkali-metal and alkaline-earth-metal cations were almost completely excluded (<0.2 mol mol(s)(-1)).