Radioactive Cesium Research Articles

Enhanced radiocesium uptake by rice with fermented bark and ammonium salt amendments

There are ongoing problems with radioactive cesium (Cs) contaminated agricultural soil after the Fukushima Daiichi Nuclear Power Plant accident. In this study, the behavior of Cs uptake by rice plants grown in soil sprayed with fermented bark amendment (FBA) was investigated. In rice cultivation by pot, the application of FBA resulted in the acceleration of Cs uptake by rice plants. This might be related to the reduction of oxidation reduction potential in the soil caused by spraying FBA. Also, when 0.1 wt% ammonium sulfate was used as a fertilizer in Cs-contaminated soil, the bioconcentration factor (BCF) of Cs taken up into rice straw was 1.4-times higher than that in soil sprayed with FBA. The Cs uptake effect was further enhanced by the combination of 1 wt% FBA with 0.1 wt% ammonium sulfate to soil where the BCF was enhanced to 1.8-times higher than that in soil sprayed with FBA alone. The enhanced uptake into rice was likely because of accelerated uptake of leachable forms of Cs based on the cation-exchange to NH4+ in soil; this was confirmed by the Cs fractionation by sequential extraction procedures. The phytoremediation capability of rice is considered to be lower than that of commonly used phytoremediation plants, but supplementation with FBA and ammonium salt could enhance Cs accumulation even for low-efficiency phytoremediation plants.

Decrease of Radioactive Cesium in Rice by Low Degree Polishing and Cooking

Decrease of Radioactive Cesium in Rice by Low Degree Polishing and Cooking

Chemical evolution effects on phase and microstructure of [CsxBay][Ti3+2y+xTi4+8-2y-x]O16 ceramic waste forms for radioactive cesium immobilization

The effects of fission product transmutation on the structural stability of ceramic waste forms are a critical concern due to the changes of valence and ionic size, which can impair the stability of the host matrices. In this study, [CsxBay][Ti3+2y+xTi4+8-2y-x]O16 (0.3 ≤ x, y ≤ 0.75) ceramics were designed and successfully synthesized to immobilized 137Cs and its daughter product 137Ba. The evolution of phase and microstructure of the hollandite-ceramic waste forms were investigated by the substitution of Ba2+ into the Cs+ site and the incorporation of Ti3+ for charge compensation. The results show that the prepared hollandite ceramics exhibit excellent capacity to accommodate Cs+ and Ba2+ in its lattice while retaining a stable crystalline structure with a compact microstructure. Additionally, all elements of Cs, Ba, Ti and O homogeneously distributed in the sintered hollandite ceramics. These results further indicate that hollandite ceramics are a promising candidate for selective and durable immobilization of radioactive cesium.

Synthesis of Ceramic and Glass Ceramic Matrices with Immobilized Cesium Radionuclides for Active Zones of Ionizing Radiation Sources

The present study was devoted to the development of alternative solutions related to replacement of highly dispersed powder of cesium chloride (137CsCl) used as a filler of active zones of g-radiation IRSs (ionizing radiation sources of the closed type) by safer and more efficient in operation highly compacted ceramic or glass ceramic material. An advanced method of fabrication of highly compacted (density of ~99.8 % of the theoretical one) aluminosilicate (artificial NaA zeolites) ceramic and glass ceramic matrices characterized with high construction strength (compression strength ~149 MPa) applicable for reliable immobilization of cesium radionuclides (leaching rate <10-5–10-6g/cm2×day) has been suggested. Unique matrices properties are ensured by advanced features of the technology of Spark Plasma Sintering (SPS) based on high-rate electro-pulse consolidation of the radioactive charge (adsorbed cesium content ~22.16 mass %) into thermodynamically stable ceramics or glass ceramics. The earlier unstudied features of the SPS consolidation of natural zeolite powders sorption-saturated with a radioactive cesium simulant are presented, including the dynamics of their compaction and specifics of phase and structural transformations under effect of irreversible spark plasma conditions.

Pre-enrichment of radioactive cesium in muddy water separated into suspended and dissolved substances for trace analysis

A new in-situ pre-enrichment system was developed for trace analysis of radioactive Cs in environmental water such as rivers, ponds, and seas, where the radioactive Cs is separated into suspended substances (SS) and dissolved substances (DS). The SS component was collected as the enrichment slurry by cross-flow filtration, thereby compact systems were realized. The DS component was collected in a small cartridge filled with a non-woven fiber with immobilized adsorbent nanoparticles. The recovery rate was estimated at around 95%. The size distribution of the SS and the concentration of radioactive Cs after enrichment were the same as that of the raw water before enrichment. The condensed SS can be used for other evaluations such as ignition loss. From the field test at a pond in the Fukushima-area, the Cs concentration of the SS was found to be 4–5 times higher than that of the sediment in the same pond. The organic content estimated by ignition loss was also three times higher.

Synthesis of Adsorbent Fixed with Prussian Blue Based by Illite and Adsorption of Soluble Radioactive Cesium (137Cs)

Prussian blue (PB) is a selective and highly adsorptive material for cesium. However, it is difficult to recover after adsorption and there is a possibility of secondary environmental pollution. In this study, the surface of illite powder was modified by using acrylic acid (AA) as a crosslinking agent for stable fixation of PB to illite powder. The aim of this study was development of adsorbent with stabilized PB at illite using AA (AA-illte-PB). In XRD analysis and FT-IR analysis results of AA-illte-PB, PB characteristic peak was founded. Those results show presence of PB in AA-illte-PB. TGA analysis was performed to confirm the polymer and PB content of the adsorbent. It was judged that AA was effectively synthesized on the surface of illite modified with AA (AA-illte) through the SEM (EDS) analysis. The PB adsorption performance of AA-illte-PB was evaluated after pretreatment of NaCl for immobilization of PB on AA-illte surface. In the case of AA-illte-PB pretreated with NaCl, the maximum adsorption amount of cesium was 5.09 mg/g and the maximum adsorption amount of cesium in AA-illte-PB without NaCl pretreatment was 2.01 mg/g. Also, results of cesium adsorption analysis using 137Cs standard source solution showed 99% removal rate for AA-illte-PB pretreated with NaCl and 88% for AA-illte-PB un-pretreated with NaCl. The efficiency of AA-illte-PB pretreated with NaCl found to be effective for cesium adsorption. UV-vis analysis was performed to identify the desorbeed PB during washing. Illite attached with PB without AA (illite-PB) was detached from a large amount of PB through 5 washes. AA-illte-PB showed a small amount of PB desorbed by the first wash. As a result, an adsorbent with stable PB immobilization was developed. Key words: Cesium, Adsorption, Desorption, Prussian Blue, Illite

Highly stable Prussian blue nanoparticles containing graphene oxide–chitosan matrix for selective radioactive cesium removal

In this work, a Prussian blue (PB)/graphene oxide (GO)/chitosan (CS) organic-inorganic composite was successfully synthesized and utilized as an adsorbent for the selective removal of cesium (Cs+) ions. Taking the advantage of synergistic effect GO, CS and PB nanoparticles, the PB/GO/CS composite exhibited maximum adsorption capacity of 48.35 mg g−1 for Cs+ ions. In the presence of competitive monovalent cations (K+ and Na+), PB/GO/CS showed excellent selectivity (86%) for Cs+ ions and had a 6-fold higher distribution coefficient (Kd) than GO/CS. This enhanced adsorption capacity with high selectivity of PB/GO/CS for Cs+ ions may have been attributed to (i) the presence of carboxylic, hydroxyl and amino functional groups on GO/CS matrix which strongly bind Cs+ ions through electrostatic attraction and chelation, and (ii) the trapping of Cs+ ions by the voids of the FCC-structured PB lattice whose size is equivalent to the hydration radius of Cs+ ions. Due to its low-cost, facile preparation, high adsorption capacity, and superior Cs+ ions selectivity, PB/GO/CS is a promising material for the selective removal of the Cs+ ions from the environment and for protecting ecosystems from the radiation hazards.

Depth Distribution of Radioactive Caesium in Soil after Cultivation and the Difference by Year of the Uptake of Radioactive Caesium in Rice in Fukushima Prefecture after the 2011 Nuclear Accident

Depth Distribution of Radioactive Caesium in Soil after Cultivation and the Difference by Year of the Uptake of Radioactive Caesium in Rice in Fukushima Prefecture after the 2011 Nuclear Accident

Reformation of the surface of powdered activated carbon (PAC) using covalent organic polymers (COPs) and synthesis of a Prussian blue impregnated adsorbent for the decontamination of radioactive cesium

Prussian blue (PB) is known to selectively adsorb cesium (Cs), with a high adsorption efficiency. However, it is difficult to collect it after adsorption, which increases the risk of secondary environmental pollution. In this study, covalent organic polymers (COPs) were used to reform the surface of powdered activated carbon (PAC) particles in order to stably immobilize PB, with the aim of developing an adsorbent impregnated with PB (COP-PAC-PB). PAC particles reformed with COPs (COP-PAC) were analyzed using TEM (EDS) and FT-IR techniques, and it was found that COPs were successfully synthesized on the surface of COP-PAC particles. COP-PAC-PB particles were synthesized by reacting PAC particles with iron(III) chloride and potassium ferrocyanide solutions in order, to synthesize PB within the pores of COPs (in situ). COP-PAC-PB particles were analyzed using XRD and FT-IR techniques, and peaks showing the general characteristics of PB were observed, which indicated that PB existed on the surface of COP-PAC-PB particles. PB was synthesized on the surface of the non-reformed groups (PAC and Ox-PAC) using the same method. In addition, UV–vis analysis was performed to compare the characteristics of PB desorbed from the non-reformed and reformed groups immediately after synthesizing and washing them. In the non-reformed groups (PAC-PB and Ox-PAC-PB), a large amount of PB was desorbed while they were washed 6 times. For COP-PAC-PB, however, a small amount of PB was desorbed during the first washing, but no desorbed PB was observed thereafter. The maximum Cs adsorption capacity of COP-PAC-PB particles was 19 mg/g, and its removal efficiency of radioactivity cesium (Cs-137, 60 Bq/kg) was 97.3%. In this study, the surface of PAC particles was effectively reformed using COPs, and an adsorbent to which PB was stably immobilized was developed.

Stability studies of [CsxBay][(Al3+,Ti3+)2y+xTi4+8-2y-x]O16 ceramics for radioactive caesium immobilization

[CsxBay][(Al3+,Ti3+)2y+xTi4+8-2y-x]O16 (0.4 ≤ x, y ≤ 0.8) ceramics were synthesized to investigate the substitution effects of Ba2+ for Cs+ on the stability of hollandite-ceramic waste forms. It was found that the substitution of Ba2+ for Cs+ in the (Cs,Ba)-hollandite system does not cause substantial variation in the crystallographic phase and microstructure. The normalized release rates of Cs and Ba at 90 °C in deionized water were < 0.005 g m−2 d−1 after 28 days. These results indicate that hollandite ceramics are an ideal host for permanent radioactive caesium disposal.

One-step synthesis of magnetic composite UiO-66/Fe3O4/GO for the removal of radioactive cesium ions

In this study, the UiO-66/Fe3O4/GO composite was prepared by one step method for removal of cesium ions (Cs+) in water and exhibited excellent adsorption capacity for Cs+ (62.07 mg g−1), which can be attributed to the size compatibility of nanosized cavities and the addition of GO. As supporting matrix, GO decreased particle aggregation and increased the surface area of the adsorbent. The composite had good acid and alkali resistance, thermal stability, rapid adsorption rate and can be separated from water by magnetic separation rapidly.

Study of soil particles contaminated with radioactive cesium in pond sediment

AbstractThe Fukushima Daiichi Nuclear Power Plant accident caused by the tsunami following the Great East Japan Earthquake in March 2011 resulted in contamination in Namie and Iitate, located in Fu...

Development of a Normal-temperature Dry Magnetic Separation System for Classifying Soil Contaminated with Radioactive Cesium and Reducing its Volume

Development of a Normal-temperature Dry Magnetic Separation System for Classifying Soil Contaminated with Radioactive Cesium and Reducing its Volume

Annual Change of Radioactive Cesium in Peach

Annual Change of Radioactive Cesium in Peach

Demonstration of Rapid Detection System for Radioactive Cesium in the Air toward Releasing the Evacuation Order in the Difficult-To-Return Zone in Fukushima

Demonstration of Rapid Detection System for Radioactive Cesium in the Air toward Releasing the Evacuation Order in the Difficult-To-Return Zone in Fukushima

Monitoring method for radioactive cesium in marine sediment after Fukushima NPP1 accident

Monitoring method for radioactive cesium in marine sediment after Fukushima NPP1 accident

Corrigendum: Demonstration of Rapid Detection System for Radioactive Cesium in the Air toward Releasing the Evacuation Order in the Difficult-To-Return Zone in Fukushima

Corrigendum: Demonstration of Rapid Detection System for Radioactive Cesium in the Air toward Releasing the Evacuation Order in the Difficult-To-Return Zone in Fukushima

Role of filamentous fungi in migration of radioactive cesium in the Fukushima forest soil environment.

The fate of radioactive Cs deposited after the Fukushima nuclear power plant accident and its associated radiological impacts are largely dependent on its mobility from surface soils to forest ecosystems. We measured the accumulation of radioactive Cs in the fruit bodies of wild fungi in a forest at Iitate, Fukushima, Japan. The transfer factors (TFs) of radioactive Cs from soil to the fruit bodies of wild fungi were between 10-2 and 102, a range similar to that reported for the fruit bodies collected in Europe after the Chernobyl accident and in parts of Japan contaminated by the nuclear bomb test fallout. Comparison of the TFs of wild mushroom and those of fungal hyphae of 704 stock strains grown on agar medium containing nutrients and 137Cs showed that the TFs of wild mushroom were lower. The TF was less than 0.1 after the addition of the minerals zeolite, vermiculite, phlogopite, smectite, or illite of 1.0% weight to the agar medium. These results indicate that the presence of minerals decreases Cs uptake by fungi grown on the agar medium, and filamentous fungi still accumulate radioactive Cs even when minerals are present in the medium.

Annual changes in radioactive cesium concentrations in needles of Cryptomeria japonica canopy trees at different leaf age

Annual changes in radioactive cesium concentrations in needles of <i>Cryptomeria japonica</i> canopy trees at different leaf age

Investigation on the form and behavior of radioactive cesium in sewage sludge

Investigation on the form and behavior of radioactive cesium in sewage sludge