Direct temperature-swing extraction of rare-earth elements from acidic solution using the hydrophobic interactions of poly(-isopropylacrylamide) with diglycolamide-typed ligands

Saga, Kaname*; Suzuki, Hideya; Matsumura, Tatsuro; Tsukahara, Takehiko*

Analytical Sciences, 35(4), p.461 - 464, 2019/04

https://doi.org/10.2116/analsci.18N023

The phase transition-based gelification phenomenon of poly--isopropylacrylamide (PNIPAAm) in aqueous solutions has a great potential in developing new waste-free extraction processes of metal ions. By using hydrophobic diglycolamide-typed ligands in gelification extraction, a one-step complete extraction of all the RE ions from a nitric acid solution was successfully realized.

Solidification of radioactive wastes using Alkali-activated materials "Geopolymer"

Meguro, Yoshihiro; Sato, Junya

Dekomisshoningu Giho, (54), p.48 - 55, 2016/09

Various radioactive wastes, especially liquiform, pulverized or grained one, have to be immobilized in a disposal container, and methods such as cement solidification, bituminization, etc are so far examined and have been adopted. In recent years novel inorganic solidification materials have been developed. These are named Alkali-activated materials and so geopolymer. Mainly studies of geopolymer applying to radioactive wastes as a solidification material are under research and development stage, but the cases applied to solidification of the real radioactive waste increase a lot. In this report, we briefly explain about some research studies and practical examples of the geopolymer in the field of nuclear energy, particularly those of radioactive wastes generated in Fukushima Daiichi Nuclear Power Station.

Development of paper sludge ash-based geopolymer and application to treatment of hazardous water contaminated with radioisotopes

Li, Z.*; Onuki, Toshihiko; Ikeda, Ko*

Materials, 9(8), p.633_1 - 633_17, 2016/08

https://doi.org/10.3390/ma9080633

Geopolymer samples were prepared at room temperature using paper sludge ashes and immobilization of Sr and Cs in these samples were evaluated by short-term leaching test. The prepared geopolymer samples were semi-crystalline and porous. For the leaching test, the geopolymer samples containing 1 weight % of strontium nitrate or cesium nitrate were prepared, crushed to be finer than 4 mm in size, and immersed in a phthalic salt buffer (pH4) for 6 h. About 0.2% of Sr and 1.3% of Cs were leached from the geopolymer samples.

Enhancement in dose sensitivity of polymer gel dosimeters composed of radiation-crosslinked gel matrix and less toxic monomers

Hiroki, Akihiro; Yamashita, Shinichi*; Taguchi, Mitsumasa

Journal of Physics; Conference Series, 573(1), p.012028_1 - 012028_4, 2015/01

BB2014-0610.pdf:0.75MB

https://doi.org/10.1088/1742-6596/573/1/012028

Polymer gel dosimeters based on radiation-crosslinked hydroxypropyl cellulose gel were prepared, which comprised 2-hydroxyethyl methacrylate (HEMA) and polyethylene glycol dimethacrylate (9G) as less toxic monomers and tetrakis (hydroxymethyl) phosphoniumu chloride (THPC) as an antioxidant. The dosimeters exposed to Co -rays became cloudy at only 1 Gy. The irradiated dosimeters were optically analyzed by using a UV-vis spectrophotometer to evaluate dose response. Absorbance of the dosimeters linearly increased in the dose range from 0 to 10 Gy. The dose sensitivity increased with increasing 9G concentration. The dosimeter with 2 wt% HEMA, 3 wt% 9G, and 0.16 wt% THPC exhibited about 0.04 Abs Gy of the dose sensitivity. The dose sensitivity of the dosimeters was also enhanced by increment in THPC, reached about 0.06 Abs Gy at 0.40 wt% THPC.

Polymeric Co-C compound phase evolved in atomistically mixed thin films

Sakai, Seiji; Naramoto, Hiroshi*; Lavrentiev, V.*; Narumi, Kazumasa; Maekawa, Masaki; Kawasuso, Atsuo; Yaita, Tsuyoshi; Baba, Yuji

Materials Transactions, 46(4), p.765 - 768, 2005/04

https://doi.org/10.2320/matertrans.46.765

A systematic study of the atom-level mixtures between Co and C has made possible to find a new C-based compound phase, CoC (x5). It is confirmed with the EXAFS analysis and the positron annihilation study that the polymeric structure is developed three-dimensionally by bridging two C molecules with the covalently bonded Co atom.

Application of radiation-graft material for metal adsorbent and crosslinked natural polymer for healthcare product

Tamada, Masao; Seko, Noriaki; Yoshii, Fumio

Radiation Physics and Chemistry, 71(1-2), p.223 - 227, 2004/09

https://doi.org/10.1016/j.radphyschem.2004.03.044

Graft polymerization and crosslinking in radiation processing were attractive techniques to modify conventional polymers. In the case of graftpolymerization, metal adsorbent was prepared by introducing the chelate function to trunk polymer like polyethylene. The obtained metal adsorbent was applied to the recovery of uranium in seawater. Three years' marine experiment revealed that 1kg of uranium could be collected by using graft-adsorbent. Natural polymers such as derivatives of starch and cellulose led irradiation crosslinking at paste-like condition and formed hydrogels. These hydrogels had degradability even after crosslinking. The mat of degradable hydrogel was effective to prevent bedsores as a healthcare product. After use, the hydrogel can be converted to fertilizer by decompositions.

Development of toxic metal adsorbent with radiation-induced graft polymerization

Tamada, Masao

Kankyo Shigen Kogaku, 51(2), p.99 - 101, 2004/04

Fibrous chelate adsorbents have been synthesized by radiation-induced graft polymerization onto polyethylene nonwoven fabric. Graft polymerization was induced by electron beam irradiation to the trunk polymer. Then, irradiated trunk polymer was contacted with reactive monomer having function of chelate agent or its precursor. The precursor was chemically converted to chelate agent. The resulting fibrous chelate adsorbent gave the high space velocity more than 500 h in removal of lead from its solution. Such adsorbent was applied to the removal of cadmium from scallop processing waste and the removal of lead from the contaminated water which was produced by washing the inside of incinerator.

Development of metal adsorbent with radiation induced graftpolymerization

Tamada, Masao

Oyo Butsuri, 72(4), p.453 - 456, 2003/04

https://ci.nii.ac.jp/naid/80015878539

Radiation induced graft-polymerization is sophisticated technique which is capable of introducing aiming functions into conventional polymers. Especially, pre-irradiation method is available for industrialization owing to discrete processes of irradiation and grafting. The chelate adsorbents having high selectivity against metals were synthesized by the graft-polymerization. The recovery of uranium from seawater and the removal of toxic metals from wastewater were described as applicable examples of the graft adsorbents.

Modification of C thin films by ion irradiation

Narumi, Kazumasa; Naramoto, Hiroshi

Surface & Coatings Technology, 158-159, p.364 - 367, 2002/09

Irradiation effect of 7 MeV C ions on C thin films on Si(111) substrates were investigated. Raman scattering spectroscopy showed that C film had been already polymerized and that depolymerization of the polymerized C films progressed up to the dose of 1.110/cm. After the depolymerization, the C films were transformed into a form of amorphous carbon at higher dose. The AFM analysis of conductivity of the film shows the results consistent with the Raman-scattering-spectroscopy analysis of the film.

Thermoresponsive conductivity of poly(-isopropylacrylamide)/potassium chloride gel electrolytes

Chen, J.; Maekawa, Yasunari; Yoshida, Masaru; Tsubokawa, Norio*

Journal of Polymer Science, Part B; Polymer Physics, 40, p.134 - 141, 2001/11

https://doi.org/10.1002/polb.10077

no abstracts in English