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Nagano, Tetsushi; Naganawa, Hirochika; Suzuki, Hideya; Toshimitsu, Masaaki*; Mitamura, Hisayoshi*; Yanase, Nobuyuki*; Grambow, B.
Analytical Sciences, 34(9), p.1099 - 1102, 2018/09
Times Cited Count：12 Percentile：45.44(Chemistry, Analytical)A previously reported emulsion flow (EF) extraction system does not include a device for refining used solvent. Therefore, the processing of large quantities of wastewater by using the EF extractor alone could lead to the accumulation of wastewater components into the solvent and diminished extraction performance. In the present study, we have developed a solvent-washing-type EF system, which is equipped with a unit for washing used solvent to prevent accumulation, and successfully applied it for treating uranium-containing wastewater.
Nagasu, Ryosuke*; Tanabe, Daijiro*; Yokotsuka, Satoshi*; Kumazawa, Noriyuki*; Ajiki, Takaya*; Aizawa, Yusuke*; Naganawa, Hirochika; Nagano, Tetsushi; Yanase, Nobuyuki*; Mitamura, Hisayoshi*; et al.
Kankyo Joka Gijutsu, 17(2), p.58 - 61, 2018/03
A new technology to suppress cesium migration from forests has been developed collaboratively by Ibaraki University, Kumagai-gumi Co., Ltd. and its group company, Technos, and JAEA. The new technology utilizes polyelectrolytes (polymers with electric charges) and clay minerals to control Cs migration with the aid of natural forces such as rainfall and rainwater runoff. In Imitate-mura, Fukushima, verification tests of the new technology have been performed and its effect on controlling Cs migration from forests to grass farm adjoining the forests has been proven.
Yamashita, Yuji*; Yanase, Nobuyuki; Nagano, Tetsushi; Mitamura, Hisayoshi; Naganawa, Hirochika
Journal of Radioanalytical and Nuclear Chemistry, 305(2), p.583 - 587, 2015/08
Times Cited Count：6 Percentile：39.74(Chemistry, Analytical)We propose a method for the decontamination and waste volume reduction of cesium-contaminated soil. The soils were solidified with an interpolyelectrolyte complex solution and classified into several size fractions by wet sieving. 
-ray spectrometry of these fractions showed that the distribution ratio of the activity concentration of coarse soil particles decreased, whereas that of soil particles under 0.075 mm increased relative to reference samples. Results show that the fine soil particles, on which radioactive cesium accumulates, were removed from the surface of the coarse soil particles during, and remained in the washing water.
Matsunaga, Takeshi; Tsuzuki, Katsunori; Yanase, Nobuyuki; Kritsananuwat, R.*; Hanzawa, Yukiko; Naganawa, Hirochika
Journal of Nuclear Science and Technology, 52(4), p.514 - 529, 2015/04
Times Cited Count：5 Percentile：39.74(Nuclear Science & Technology)In a temperate, forested river catchment, distribution of dissolved rare earth elements (REE) during rainfall events was studied as analogues elements for transuranic nuclides. Concentrations of dissolved REE showed almost concurrent increases and decreases with the river water discharge during rainfall events. The concentration variations were tightly coupled with those of optical properties related to humic substances of dissolved organic matter (DOM). An ultrafiltration analysis revealed that colloidal REE present in 10 k - 30 kDa size fraction was the chief component for dissolved REE increase in high water flow condition. Shale-normalized concentration patterns of REE suggest an involvement of humic substances of DOM. A high correlation between size fractioned REE concentrations and specific ultraviolet absorbance suggests that aromaticity would be an essential property of DOM in regard to its complexation with dissolved REE in the studied river water.
Kanda, Nobuhiro; Daiten, Masaki; Endo, Yuji; Yoshida, Hideaki; Mita, Yutaka; Naganawa, Hirochika; Nagano, Tetsushi; Yanase, Nobuyuki
JAEA-Technology 2015-007, 43 Pages, 2015/03
JAEA-Technology-2015-007.pdf:5.33MB
The centrifuge which has the subtlety information concerning the nuclear nonproliferation used for uranium enrichment technical development exists in the uranium enrichment facilities of Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency. This centrifugal is performing separation processing of the radioactive material adhering to the surface of parts by wet decontamination of ultrasonic cleaning by dilute sulfuric acid and water, etc. By removing the uranium contained in waste fluid, generated sludge reduces activity concentration. And the possibility of reduction of sludge processing is examined. For this reason, from the 2007 fiscal year, Nuclear Science and Engineering Directorate and cooperation are aimed at, and development of the extraction separation technology of the "uranium" by the emulsion flow method is furthered. The test equipment using the developed emulsion flow method was tested. And dilute sulfuric acid and water were used for the examination as actual waste fluid. The result checked whether the various performances in Basic test carried out in Nuclear Science and Engineering Directorate would be obtained.
Nagano, Tetsushi; Mitamura, Hisayoshi; Yanase, Nobuyuki; Naganawa, Hirochika; Yasuda, Kenichiro; Yamaguchi, Hiroaki*
Hoshasei Busshitsu No Kyuchaku, Josen Oyobi Taihoshasen Gjutsu Ni Okeru Zairyo, Seko, Sokutei No Shin Gijutsu, p.400 - 408, 2014/11
A method for monitoring radioactive cesium concentration in water using a cesium adsorption disk and a GM survey meter has been developed to ascertain whether the water quality meets standards on radiological contaminants in water. This method was successfully applied to monitoring of decontaminated water of an outdoor school swimming pool in Date City after Fukushima Daiichi Nuclear Power Plant accident.
Matsunaga, Takeshi; Tsuzuki, Katsunori; Yanase, Nobuyuki; Kritsananuwat, R.*; Ueno, Takashi; Hanzawa, Yukiko; Naganawa, Hirochika
Limnology, 15(1), p.13 - 25, 2014/01
Times Cited Count：8 Percentile：27.29(Limnology)We studied a discharge of heavy metals/metalloids in rainfall events to a rural stream in Kuji River basin of central Japan. In terms of elemental enrichment with respect to the crustal composition, we found similarity between atmospheric deposits and suspended particulate matter (SPM) at a rural stream. Both exhibited distinctive enrichment in several metals (Ni, Cu, Pb, Sb, and Cd). Elemental analysis of SPM in the stream in rainfall events at short intervals revealed that the metal enrichment factors in SPM were progressively decreased with an increase of flow rate. Judging from features of SPM, this phenomenon was probably caused by alternative change of SPM matrices from upper soil constituents to more lithologic material with increasing stream flow rate. In quantification of respective contributions of metals of different origins to fluvial discharge, change of SPM matrices during a rainfall event and involvement of dissolved fraction need to be taken into consideration.
Nagano, Tetsushi; Mitamura, Hisayoshi; Yamashita, Yuji; Yanase, Nobuyuki; Suzuki, Hideya; Naganawa, Hirochika
Solvent Extraction Research and Development, Japan, 21(1), p.111 - 117, 2014/00
Simulated electroless nickel plating liquid wastes have been processed by using an emulsion flow extractor of a counter current type with a special focus on influences of dilution of the liquid wastes on the extraction performance. The emulsion flow extractor provides an efficient liquid-liquid extraction by sending solutions without additional stirring or shaking. A solvent used in the present study was Shellsol D70 solution containing LIX84-I as an extractant for nickel and PC88A as an accelerating agent. As a result, it was found that increasing degree of dilution with water resulted in improvement of nickel extractabilities obtained from the emulsion flow experiments with a maximum value of 96% as well as those obtained from batch experiments. Droplet sizes at the lower and the upper sides of emulsion phases, estimated by using high-speed microscope, were 214 
36 
m and 415 110 m, respectively.
Nagano, Tetsushi; Yanase, Nobuyuki; Naganawa, Hirochika; Mitamura, Hisayoshi; Hanzawa, Yukiko; Mita, Yutaka; Kanda, Nobuhiro; Ohashi, Yusuke; Endo, Yuji; Matsubara, Tatsuo
Nihon Genshiryoku Gakkai Wabun Rombunshi, 12(4), p.277 - 285, 2013/12
no abstracts in English
Nagano, Tetsushi; Mitamura, Hisayoshi; Yanase, Nobuyuki; Naganawa, Hirochika; Yasuda, Kenichiro; Yoshida, Zenko; Yamaguchi, Hiroaki*
Nihon Hoshasen Anzen Kanri Gakkai-Shi, 11(2), p.139 - 145, 2012/11
An on-site monitoring method for radioactive cesium concentration in water using a cesium adsorption disk and a GM survey meter has been developed to rapidly and easily ascertain whether the water quality meets standards on radiological contaminants in water. In this method, both dissolved and suspended forms of radioactive cesium are collected on the cesium adsorption disk by means of filtration of a water sample. Beta counting rate of the disk is converted into radioactivity using a conservative calibration factor obtained here. The present on-site method was applied to monitoring of decontaminated water of an outdoor school swimming pool in Date city after Fukushima Dai-ichi Nuclear Power Plant accident.
Naganawa, Hirochika; Kumazawa, Noriyuki*; Saito, Hiroshi*; Yanase, Nobuyuki; Mitamura, Hisayoshi; Nagano, Tetsushi; Kashima, Kaoru*; Fukuda, Tatsuya*; Yoshida, Zenko; Tanaka, Shunichi*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(4), p.227 - 234, 2011/12
no abstracts in English
Yanase, Nobuyuki; Naganawa, Hirochika; Nagano, Tetsushi; Noro, Junji*
Analytical Sciences, 27(3), p.325 - 330, 2011/03
Times Cited Count：9 Percentile：29.7(Chemistry, Analytical)JP, 2008-253779
Licensable Patent Information Database Patent publication (In Japanese)
A single current "emulsion flow" liquid-liquid extraction apparatus has a head having a number of holes from which micrometer-sized droplets of an aqueous phase spout into an organic phase to mix the two liquid phases. For practical use, however, it is a fatal problem that particulate components in the aqueous phase plug the holes. In the present study, we have succeeded to solve the problem by applying a counter current type emulsion flow apparatus where micrometer-sized droplets of the organic phase are generated.
Naganawa, Hirochika; Suzuki, Hideya*; Yanase, Nobuyuki; Nagano, Tetsushi; Noro, Junji*
Analytical Sciences, 27(3), p.321 - 324, 2011/03
Times Cited Count：9 Percentile：29.7(Chemistry, Analytical)In order to monitor a radioactive nuclide of strontium-90 in seawater around nuclear facilities, a solvent extraction method for collecting Sr(II) in seawater was examined. A reversed-micellar extraction system containing an anionic surfactant AOT and a molecular extractant TODGA in n-hexane was chosen for the extraction of Sr(II) from model solutions of seawater containing 0.5 M NaCl (1 M = 1 mol dm
), 0.05 M MgCl
, and/or 0.01 M CaCl. The combination of AOT forming reversed micelles and TODGA coordinating with Sr(II) as an organic ligand (extractant) was found to be efficient for the extraction of Sr(II) from the model solutions. The mechanism of the reversed-micellar extraction system was also discussed in the present study.
Nagano, Tetsushi; Yanase, Nobuyuki; Hanzawa, Yukiko; Takada, Morio*; Mitamura, Hisayoshi; Sato, Tsutomu*; Naganawa, Hirochika
Water, Air, and Soil Pollution, 216(1-4), p.153 - 166, 2011/03
Times Cited Count：10 Percentile：31.59(Environmental Sciences)Schwertmannite is a poorly-crystalline ferric sulphate mineral that secondarily forms in acid mine drainages (AMD) as a result of the oxidative weathering of pyrite (FeS2), and is known to work as a naturally-occurring scavenger of some toxic elements in AMD-contaminated streams due to its high fixation potentials. In this study, to examine the feasibility of using schwertmannite in water purification technique, we evaluate the affinity of some selected elements to schwertmannite using two parameters: (1) conventional apparent solid-liquid partition coefficients between schwertmannite and stream waters, and (2) newly introduced parameters that correspond to ratios of ions fixed by schwertmannite to those existing as dissolved phases. As a result, both of the two parameters revealed that schwertmannite has high fixation potential for fluvial transport of various toxic anions such as V, Cr, As, Mo and Sb in AMD-contaminated streams, and that it could be used for purification of waters contaminated with these toxic anions.
Yanase, Nobuyuki; Naganawa, Hirochika; Nagano, Tetsushi; Noro, Junji*
Analytical Sciences, 27(2), p.171 - 174, 2011/02
Times Cited Count：14 Percentile：42.63(Chemistry, Analytical)JP, 2007-136496Licensable Patent Information Database Patent publication (In Japanese)
A simple and low-cost apparatus for continuous and efficient liquid-liquid extraction, which does not need continual mechanical forces (stirring, shaking, etc.) other than solution sending, has newly been developed. This apparatus is composed of a column part where an emulsion state fluid flow (emulsion flow) is generated by spouting micrometer-sized droplets of an aqueous phase into an organic phase and a phase separating part where the emulsion flow is destabilized by means of a sudden decrease in its flow rate. In the present study, the performance of an emulsion flow apparatus in the extraction of Yb(III) and U(VI) from aqueous HNO
solutions into isooctane containing D2EHPA was evaluated. The mixing efficiency of the emulsion flow apparatus was found to be comparable with that of a popular liquid-liquid extractor, mixer-settler. Moreover, the emulsion flow apparatus proved to have an overwhelming advantage in terms of phase-separating ability.
Mitamura, Hisayoshi; Naganawa, Hirochika; Nagano, Tetsushi; Yanase, Nobuyuki; Hanzawa, Yukiko; Shimojo, Kojiro; Matsubara, Tatsuo; Mita, Yutaka; Taki, Tomihiro; Murata, Masato
JAEA-Research 2008-113, 27 Pages, 2009/03
JAEA-Research-2008-113.pdf:31.84MB
An effective mass processing equipment using solvent extraction method, named "emulsion flow extractor," is the most promising apparatus for removal and recovery of uranium from liquid waste originated from decontamination of uranium-contaminated fluoride waste in the uranium conversion test facility and of used gas centrifuges in the uranium enrichment facility at Ningyo-toge environmental engineering center. Prior to application of the emulsion flow extractor for actual uranium-containing liquid waste, properties of some phosphorous extractants for extraction and separation of uranium and constituents from simulated liquid wastes were examined through batch tests. These preliminary tests revealed that D2EHPA would be a promising candidate for extractant used for treatment of the actual uranium-containing liquid wastes, and that the extractants with a surfactant like AOT would not be useful.
Matsunaga, Takeshi; Yanase, Nobuyuki; Kritsananuwat, R.*; Tsuzuki, Katsunori; Hanzawa, Yukiko; Naganawa, Hirochika
Proceedings of 12th International Conference on Integrated Diffuse Pollution Management (IWA DIPCON 2008) (CD-ROM), p.370 - 371, 2008/08
The input of toxic trace elements to river water in a rainfall event was studied in a forested watershed in Japan. The riverine input of particulate trace elements varied with their different enrichment in suspended particles at low and high flow stages. This input was suspected to cause an increase in the levels of their dissolved components earlier in the rainfall and at a high flow stage. We also found that dissolved organic carbon from a soillayer can carry rare earth elements to a stream at a latter stage of high flow rate.
Matsunaga, Takeshi; Yanase, Nobuyuki; Hanzawa, Yukiko; Tsuzuki, Katsunori; Naganawa, Hirochika
JAEA-Research 2007-056, 143 Pages, 2007/07
JAEA-Research-2007-056.pdf:59.02MB
Stream discharge of metallic elements from the ground was investigated in a forested catchment in the Oda River watershed in the central Japan. The investigation revealed that several hazardous metals such as Cu, Sb and Cr in dissolved form and also rare earth elements are peculiar elements whose stream discharges are always accelerated in a rainfall event. Further, two different schemes of elemental transport in this peculiar discharge were suggested. They were (1) a coincidently occurring discharge with an initial increase in a flow rate of a stream, and (2) a discharge with slower increase and prolonged decrease, which are poorly corresponding to the change in the stream flow rate. An analysis of hydrological discharge, using chemical signatures of natural organic materials (NOM) and isotopic signatures of deuterium and oxygen of water suggested that the latter discharge is associated with that of NOM of the soil layer. The latter discharge was also effective for rare earth elements.
Matsunaga, Takeshi; Tsuzuki, Katsunori; Yanase, Nobuyuki; Hanzawa, Yukiko; Naganawa, Hirochika; Inoue, Takanobu*; Yamada, Toshiro*; Miyata, Akifumi*
Proceedings of International Symposium on Environmental Modeling and Radioecology, p.243 - 246, 2007/03
The aim of this work is to obtain a fundamental scheme of stream discharge of inorganic toxic materials derived from Characteristics of the stream discharge of metallic elements were investigated in two forested catchments in the Oda River and the Ijira River watersheds. Precipitations, stream water and soil water samples were collected in raining events and were analyzed for inorganic elements, dissolved organic carbon and isotopic abundance of deuterium. Results revealed an accelerated discharge of specific metals of Cu, Sb and Cr and all the studied REE in dissolved form. This feature was commonly found in the two catchments. The specific metals are strongly suspected to be of anthropogenic origin. An analysis of hydrological discharge, using chemical and isotopic tracers, suggested that the increased discharge of the metals originate from their deposits on the ground surface and/or instantaneous resuspension of stream sediment. Contrary, REE discharge was tightly coupled with that of dissolved humic substances.
Manaka, Mitsuo*; Yanase, Nobuyuki; Sato, Tsutomu*; Fukushi, Keisuke*
Geochemical Journal, 41(1), p.17 - 27, 2007/00
Times Cited Count：29 Percentile：56.1(Geochemistry & Geophysics)Natural attenuation was investigated for the antimony in the drainage water of an abandoned mine. Drainage water, waste rocks, and ocherous precipitates collected from the mine were investigated in terms of their mineralogy and chemistry. The chemistry of the drainage water was analyzed by measuring pH, ORP, and EC on site as well as by ICP-MS and ion chromatography. The results of these investigations indicated that Sb, which is generated by the dissolution of stibnite (SbS) and secondary formed Sb minerals in waste rocks, was attenuated by iron-bearing ocherous precipitates, especially schwertmannite, that form over time in the drainage water. Bulk distribution coefficients (Kd) for this Sb adsorption to the precipitates ranges up to at least 10
L/kg.