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Chromium(VI) adsorption-reduction using a fibrous amidoxime-grafted adsorbent

林 菜月*; 松村 大樹; 保科 宏行*; 植木 悠二*; 辻 卓也; Chen, J.*; 瀬古 典明*

Separation and Purification Technology, 277, p.119536_1 - 119536_8, 2021/12

 被引用回数:5 パーセンタイル:51.75(Engineering, Chemical)

To develop a safe and simple method for the reduction of toxic chromium(VI) to the less harmful chromium(III), we proposed using radiation-induced graft polymerization. This method allows for any functional group to be introduced into conventional polymeric materials. Herein, we synthesized a fibrous adsorbent with amidoxime functional groups that have a high affinity for chromium, and investigated the changes in the chromium valence state over time in the amidoxime-grafted adsorbent. In situ X-ray absorption fine structure analysis revealed that most of the chromium(VI) was reduced to chromium(III) relatively early during the adsorption process, followed by gradual changes in the bonding structure of the amidoxime-chromium complex. It is expected to contribute to the development of practical technologies for wastewater treatment.


Non-invasive imaging of radiocesium dynamics in a living animal using a positron-emitting $$^{127}$$Cs tracer

鈴井 伸郎*; 柴田 卓弥; 尹 永根*; 船木 善仁*; 栗田 圭輔; 保科 宏行*; 山口 充孝*; 藤巻 秀*; 瀬古 典明*; 渡部 浩司*; et al.

Scientific Reports (Internet), 10, p.16155_1 - 16155_9, 2020/10

 被引用回数:0 パーセンタイル:0.01(Multidisciplinary Sciences)

Visualizing the dynamics of cesium (Cs) is desirable to understand the impact of radiocesium when accidentally ingested or inhaled by humans. The positron-emitting nuclide $$^{127}$$Cs was produced using the $$^{127}$$I ($$alpha$$, 4n) $$^{127}$$Cs reaction, which was induced by irradiation of sodium iodide with a $$^{4}$$He$$^{2+}$$ beam from a cyclotron. We excluded sodium ions by using a material that specifically adsorbs Cs as a purification column and successfully eluted $$^{127}$$Cs by flowing a solution of ammonium sulfate into the column. We injected the purified $$^{127}$$Cs tracer solution into living rats and the dynamics of Cs were visualized using positron emission tomography; the distributional images showed the same tendency as the results of previous studies using disruptive methods. Thus, this method is useful for the non-invasive investigation of radiocesium in a living animal.


Microscopic analyses on Zr adsorbed IDA chelating resin by PIXE and EXAFS

荒井 陽一; 渡部 創; 大野 真平; 野村 和則; 中村 文也*; 新井 剛*; 瀬古 典明*; 保科 宏行*; 羽倉 尚人*; 久保田 俊夫*

Nuclear Instruments and Methods in Physics Research B, 477, p.54 - 59, 2020/08

 被引用回数:1 パーセンタイル:18.5(Instruments & Instrumentation)

Used PUREX process solvent generated from reprocessing process of spent nuclear fuel contains a small amount of U and Pu complexed with tributyl phosphate (TBP) or dibutyl phosphate (DBP). The radioactive nuclides should be removed from the solvent for safety storage or disposal. The iminodiacetic acid (IDA) type chelating resin was proposed as promising procedures for efficient recovery of the trapped cations in the solvent. In order to reveal the distribution and amount of Zr in the particle and local structure of Zr complex formed in the adsorbent, PIXE and EXAFS analyses on the Zr adsorbed chelating resin were carried out. Micro-PIXE analysis proved that it is an effectual method for quantitative analysis of trace adsorbed elements. Moreover, some of the adsorption sites were possibly occupied by the molecules. On the other hand, Zr-K edge EXAFS analysis suggested that extraction mechanism of Zr from the aqueous solution and the solvent was different.


Quantitative analysis of Zr adsorbed on IDA chelating resin using Micro-PIXE

荒井 陽一; 渡部 創; 大野 真平; 野村 和則; 中村 文也*; 新井 剛*; 瀬古 典明*; 保科 宏行*; 久保田 俊夫*

QST-M-23; QST Takasaki Annual Report 2018, P. 59, 2020/03

Radioactive spent solvent waste contains U and Pu is generated from reprocessing process of spent nuclear fuel. The nuclear materials should be removed from the solvent for safety storage or disposal. We are focusing on the nuclear materials recovery from spent solvent using imino diacetic acid (IDA) type chelating resin as a promising method. In order to reveal adsorbed amount of Zr, which is simulated of Pu, Micro-Particle Induced X-ray Emission (PIXE) was carried out. Micro-PIXE analysis succeeded in quantitative analysis on trace amount of adsorbed Zr from simulated spent solvent.


STRAD project for systematic treatments of radioactive liquid wastes generated in nuclear facilities

渡部 創; 小木 浩通*; 荒井 陽一; 粟飯原 はるか; 高畠 容子; 柴田 淳広; 野村 和則; 神谷 裕一*; 浅沼 徳子*; 松浦 治明*; et al.

Progress in Nuclear Energy, 117, p.103090_1 - 103090_8, 2019/11


 被引用回数:7 パーセンタイル:70.89(Nuclear Science & Technology)

A new collaborative research project for systematic treatments of radioactive liquid wastes containing various reagents generating in nuclear facilities was started from 2018 initiated by Japan Atomic Energy Agency. The project was named as STRAD (Systematic Treatments of RAdioactive liquid wastes for Decommissioning) project. Tentative targets to be studied under the project are aqueous and organic liquid wastes which have been generated by experiments and analyses in a reprocessing experimental laboratory of JAEA. Currently fundamental studies for treatments of the liquid wastes with complicated compositions are underway. In the STRAD project, process flow for treatment of ammonium ion involved in aqueous waste was designed though the inactive experiments, and decomposition of ammonium ion using catalysis will be carried out soon. Adsorbents for recovery of U and Pu from spent solvent were also developed. Demonstration experiments on genuine spent solvent is under planning.


Analysis on adsorbent for spent solvent treatment by micro-PIXE and EXAFS

荒井 陽一; 渡部 創; 大野 真平; 中村 雅弘; 柴田 淳広; 中村 文也*; 新井 剛*; 瀬古 典明*; 保科 宏行*; 羽倉 尚人*; et al.

International Journal of PIXE, 29(01&02), p.17 - 31, 2019/00

PUREX再処理等の試験研究により、U, Puを含む廃溶媒が発生し、安全な保管や廃棄の観点から、廃溶媒からの核燃料物質の回収は重要なプロセスである。そこで、Pu(IV)の模擬としてZr(IV)を用いて模擬廃溶媒を調製し、固体吸着材による回収法を検討し、イミノ二酢酸を導入した吸着材が廃溶媒中からの核燃料物質回収に有効であるとの結果を得ている。実用化に向けては吸着量の向上が課題であったことから、イミノ二酢酸の導入量を増加させるためにポリマーを被覆した多孔質シリカの利用を検討し、そのポリマーにイミノ二酢酸を導入することで吸着材を合成した。合成した吸着材について、廃溶媒処理への適用性を評価するためには、吸着能力と吸着メカニズムを明らかにする必要がある。そこで、微量元素の測定が可能であるマイクロPIXE分析に着目し、吸着したZrの分布や量を測定することで、吸着材に導入したイミノ二酢酸基の利用効率を評価した。また、吸着材中のイミノ二酢酸に吸着したZr周りの局所構造を明らかとするためにEXAFS分析を実施した。それぞれの分析結果から、本件で合成した吸着材は溶媒中でもZrと吸着反応を示すことを確認したが、沈殿と推察される粒子が観察され、吸着材の合成方法の更なる改善が必要である。


Development of a water purifier for radioactive cesium removal from contaminated natural water by radiation-induced graft polymerization

瀬古 典明*; 保科 宏行*; 笠井 昇*; 柴田 卓弥; 佐伯 誠一*; 植木 悠二*

Radiation Physics and Chemistry, 143, p.33 - 37, 2018/02

 被引用回数:14 パーセンタイル:87.05(Chemistry, Physical)

Six years after the Fukushima-nuclear accident, the dissolved radioactive cesium (Cs) is now hardly detected inenvironmental natural waters. These natural waters are directly used as source of drinking and domestic waters in disaster-stricken areas in Fukushima. However, the possibility that some radioactive Cs adsorbed on soil or leaves will contaminate these natural waters during heavy rains or typhoon is always present. In order for the returning residents to live with peace of mind, it is important to demonstrate the safety of the domestic waters that they will use for their daily life. For this purpose, we have synthesized a material for selective removal of radioactive Cs by introducing ammonium 12-molybdophosphate (AMP) onto polyethylene nonwoven fabric through radiation-induced emulsion graft polymerization technique. Water purifiers filled with the grafted Csadsorbent were installed in selected houses in Fukushima. The capability of the grafted adsorbent to remove Cs from domestic waters was evaluated for a whole year. The results showed that the tap water filtered through the developed water purifier contained no radioactive Cs, signifying the very effective adsorption performance of thedeveloped grafted adsorbent. From several demonstrations, we have commercialized the water purifier named "KranCsair".


Evaluation of a cesium adsorbent grafted with ammonium 12-molybdophosphate

柴田 卓弥; 瀬古 典明; 天田 春代; 笠井 昇; 佐伯 誠一; 保科 宏行; 植木 悠二

Radiation Physics and Chemistry, 119, p.247 - 252, 2016/02

 被引用回数:10 パーセンタイル:72.82(Chemistry, Physical)

A fibrous adsorbent for radioactive cesium (Cs) removal has been developed by radiation induced graft polymerization. To apply the developed adsorbent to drinking water, the stability of adsorbent having high affinity for Cs ligand, ammonium 12-molybdophosphate (AMP), was evaluated. As a result, since a crosslinking structure was introduced onto the grafted AMP, it could be successfully satisfied the regulation of Food Sanitation Act. Finally, the Cs adsorbent was commercialized as water purifier named by "KranCsairtextregistered".


放射線加工技術を駆使した金属捕集材の開発; 環境浄化と資源確保を目指して

瀬古 典明

電気評論, 100(12), p.47 - 51, 2015/12




瀬古 典明; 柴田 卓弥; 笠井 昇; 植木 悠二; 佐伯 誠一; 保科 宏行

放射線と産業, (138), p.9 - 12, 2015/06

福島の原子力発電所災害以降、環境資源材料研究グループでは環境中の水域に飛散した放射性物質のうち、特にセシウムに対して効果のある捕集材料の開発を進めてきた。これまでの実績から水に対して接触効率が良好で、取り扱いの簡便な不織布繊維を基材に用い、これにセシウムに対して親和性のある吸着基を量子ビーム技術を活用した放射線グラフト重合技術により導入した。材料の評価では、福島被災地の各所で実施したフィールドテストで評価を重ね、最終的には井戸水, 沢水を対象にした飲用水向けのモニター試験を進め、その良好な結果から給水器の発売に繋げた経緯について紹介する。


Evaluation of antibacterial effect by using a fibrous grafted material loaded Ag ligand

柴田 卓弥; 瀬古 典明; 笠井 昇; 保科 宏行; 植木 悠二

International Journal of Organic Chemistry, 5(2), p.100 - 107, 2015/06

To obtain the safety of drinking water, an antibacterial material was prepared by loading Ag onto fibrous iminodiacetate (IDA) adsorbent, which was synthesized by radiation induced graft polymerization of a glycidyl methacrylate and subsequent chemical modification of the produced epoxy group to an IDA group(IDA-Ag). A total amount of loaded Ag on the IDA-Ag fabric was 0.4 mmol-Ag/g-fabric. As a result of evaluating antibacterial effects by the column mode water flow test with a stream water, the effective Ag concentration was monitored 0.05 ppm at irrespective of flow rate which was functioned to the antibacterial performance. The antibacterial effects for general bacteria were indicated until BV (BV: steam water volume/IDA-Ag fabric volume) 6,000, and for colitis germ legions were completely disinfected until BV 6,000.


Development of an adsorbent for Cs removal synthesized by radiation-induced graft polymerization

柴田 卓弥; 瀬古 典明; 天田 春代; 笠井 昇; 佐伯 誠一; 保科 宏行; 植木 悠二

日本イオン交換学会誌, 26(1), p.9 - 14, 2015/01

It is important task for recovering of Cs from the contaminated area caused by the accident at the Fukushima Daiichi Nuclear Power Station. We developed a highly efficient Cs adsorbent by radiation grafting of ammonium 12-molybdophosphate (AMP) and crosslinking of grafted chains with a suitable crosslinker at the same time. As a result of the optimizaion, the Cs adsorbent with 1 mol% of polyethylene glycol dimethacrylate satisfied the specification as a water purifier. The resultant grafted Cs adsorbent could work to maintain the highly performance of Cs removal in the standard pH range for drinking water (from pH 5.8 to 8.6) and even in the presence of coexisting ions such as K, Ca, Mg, and Na.


The Volume reduction method of radioactively-contaminated plant waste through extraction and removal of radioactive cesium

佐伯 誠一; 柴田 卓弥; 保科 宏行; 植木 悠二; 笠井 昇; 瀬古 典明

日本イオン交換学会誌, 25(4), p.170 - 175, 2014/11

After Fukushima Daiichi Nuclear Power Plant accidents, a lot of contaminated wastes have been produced by decontamination works at contaminated areas around Fukushima prefecture, Japan. At some temporary storage sites, it was found that contaminated leaching water was accumulated under stacks of contaminated "plant" wastes. To handle the wastes and the solution properly, decontamination tests of the leaching water were examined with molybdophosphate type cesium adsorbents synthesized by radiation-induced grafting method. At batch adsorption tests, 75% of radioactive cesium was successfully removed with cesium adsorbents. At column adsorption tests, radioactivity concentration of the leaching water could be reduced under provisional limit value up to around 500 times volume as large as an adsorbent volume. For development of volume reduction method of contaminated plant wastes, radioactive cesium extraction tests from the wastes and removal tests from the extracts were executed using contaminated oil cakes of sunflower seeds as a model of contaminated plant wastes. As a result, 65% of radioactive cesium was successfully extracted from the oil cakes to liquid phase, and more than 65% of radioactive cesium could be collected from the extract by grafted cesium adsorbents. These results showed a possibility of an application of these processes to volume reduction method for contaminated plant wastes.


Evaluation of the scandium affinity under the iron coexistence using radiation grafted adsorbents

林 菜月*; 保科 宏行; 天田 春代; 山延 健*; 瀬古 典明

日本イオン交換学会誌, 25(4), p.105 - 108, 2014/11

A fibrous phosphoric acid adsorbents for scandium were synthesized by radiation graft polymerization of glycidyl methacrylate (GMA), subsequent chemical modification, and direct grafting with a phosphoric monomer having both vinyl and phosphoric groups onto a polypropylene coated by polyethylene nonwoven fabric. The resultant grafted fibrous phosphoric acid adsorbent (HMP-g) having long side grafted chains has high affinity for scandium (Sc) ions even under the coexistence with Fe ion. The breakthrough capacity for Sc of 0.5 ppm with Fe coexistence was 10.9 mol-Sc per kg-adsorbent for the GMA derivative phosphoric adsorbent, and 17.8 mol-Sc per kg-adsorbent for HMP-g, respectively.


Recovery of scandium from hot spring water with graft adsorbent containing phosphoric groups

保科 宏行; 笠井 昇; 天田 春代; 高橋 牧克*; 田中 和也*; 瀬古 典明

日本イオン交換学会誌, 25(4), p.248 - 251, 2014/11

An adsorbent for Scandium (Sc) recovery was developed with radiation-induced graft polymerization of phosphoric acids that have a high affinity for Sc onto polyethylene fabrics. The adsorption performance of Sc was evaluated with the Sc adsorption equipment, consisting of 155 mm internal diameter columns and a pump that were set up near Yukawa River in Kusatsu town. To achieve a practical use of Sc recovery, the adsorbent requires repeated use with maintaining its efficiency in terms of cost reduction. So, the reusability of the adsorbent was investigated by repeating adsorption and elution. The breakthrough curves of Sc adsorption showed similar behavior in all tests. The adsorbed Sc from the 19th adsorption test was 56 mg, which was comparable capacity to the average amount of the adsorbed Sc during the 19 tests. These results indicated that the adsorbent was used more than 19 times with maintaining high adsorption performance of Sc.


A New eco-friendly synthesis method for arsenic adsorbent

天田 春代; 高橋 牧克*; 保科 宏行; 瀬古 典明

日本イオン交換学会誌, 25(4), p.109 - 113, 2014/11

A large amount of arsenic waste solution which was dissolved in neutral aqueous media, was generated from the manufacturing process of gallium arsenide component in semiconductor industry. As for arsenic removal, an adsorbent was developed by radiation graft polymerization and subsequent chemical modification with N-methyl-D-glucamine (NMDG) as a functional group. Furthermore, the grafting and the modification were carried out using water based solvent instead of organic solvent in view of an environmental emission and a working environment. The solvents were comprised of water and surfactant, and the adsorption performances compared with a conventional method synthesized in 1,4-dioxane of organic solvent. Total amount of arsenic for arsenic(III) and arsenic(V) at pH 6.5 were 3.2 times and 2.1 times higher than our previous fibrous adsorbent. From the pH dependency studies, the developed grafted adsorbent gave high removal ratio in a neutral media area for both arsenic species. Breakthrough capacities in the column mode tests for arsenic(III) and arsenic(V) were 0.3 and 18 mg/g at pH 6.5, respectively.


Adsorption properties of styrenesulfonate-grafted fibrous metal adsorbent

植木 悠二; 佐伯 誠一; 瀬古 典明

日本イオン交換学会誌, 25(4), p.99 - 104, 2014/11

The dynamic adsorption/elution properties of an ethyl p-styrenesulfonate (EtSS)-based fibrous graft adsorbent having sulfonic acid (SO$$_{3}$$H) groups were evaluated by column-mode adsorption/elution tests for various cations. The EtSS-based fibrous graft adsorbent could work to capture various cations rapidly even under high flow rate conditions, compared with a commercial granular resin. The reason for this difference of adsorption rates was thought to be that the target ions were easily and rapidly transported near the SO$$_{3}$$H groups of graft chains by fluid convection. The affinity order of the fibrous graft adsorbent for cations depended on the cationic size and valence. It was found that the EtSS-based fibrous graft adsorbent preferentially adsorbed more multiply-charged cations having a larger cationic radius. The adsorbed cations could be easily eluted and concentrated by 1 M HNO$$_{3}$$ aqueous solution, and the recovery of each cation was reached over 90%. Based on the above results, it was found that the EtSS-based fibrous graft adsorbent could be available as a sophisticated metal adsorbent in the industrial processes.


Synthesis of highly-selective fibrous adsorbent by introducing 2-ethylhexyl hydrogen-2-ethylhexylphosphonate for scandium adsorption

保科 宏行; 植木 悠二; 佐伯 誠一; 瀬古 典明

International Journal of Organic Chemistry, 4(3), p.195 - 200, 2014/09

2-Ethylhexyl hydrogen-2-ethylhexylphosphonate (EHEP) is commonly used as a metal extractant because it has a particular affinity for rare-earth metals like Scandium (Sc). To develop a highly-selective polymeric adsorbent of Sc(III), EHEP was introduced as a functional group onto a polyethylene fabric with radiation-induced graft polymerization (RIGP). The adsorption performances for Sc(III) were evaluated in aqueous solutions containing Sc(III) and Fe(III) by a column test. The adsorption capacities of Sc(III) and Fe(III) until the bed volume reached 5000 were 5.22 and 0.12 mg/g, respectively. The adsorbents showed 44 times higher Sc(III) adsorption capacity than that of Fe(III). These results indicated that the grafted adsorbent containing EHEP had an extremely high selectivity for Sc(III) adsorption.


Optimization of grafted fibrous polymer as a solid basic catalyst for biodiesel fuel production

植木 悠二; 佐伯 誠一; 柴田 卓弥; 保科 宏行; 笠井 昇; 瀬古 典明

International Journal of Organic Chemistry, 4(2), p.91 - 105, 2014/06



Effect of initial radical concentration on radiation-induced graft polymerization on polyethylene nonwoven fabric

佐伯 誠一; 岡屋 慶子*; 瀬古 典明

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 54, 2014/03


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