Removal of cesium ions from contaminated seawater in closed area using adsorptive fiber

Someya, Takaaki*; Asai, Shiho; Fujiwara, Kunio*; Sugo, Takanobu*; Umeno, Daisuke*; Saito, Kyoichi*

Nihon Kaisui Gakkai-Shi, 69(1), p.42 - 48, 2015/02

A large amount of seriously contaminated sea water with radioactive Cs has been reserved in semi-enclosed coastal sea area which is separated by silt fences and embankments. Insoluble cobalt ferrocyanide (Co-FC) microparticles-impregnated fiber was developed for removing Cs from the contaminated sea water. The resultant Co-FC-impregnated fiber was immersed in either nonradioactive or radioactive Cs solution. The adsorption isotherm well correlated with a Langmuir-type equation. In addition, mass-transfer capacity coefficients were determined by fitting the experimental data of the rate of Cs adsorption onto the Co-FC-impregnated fiber to theoretical adsorption curves based on the Cs concentration difference between the bulk and the interface in seawater as a driving force of the overall adsorption rate. Decontamination factors as functions of fiber weight and the contact time required for the removal of cesium ions from the contaminated seawater in a closed area were estimated.

Impregnation of a neutral extractant to hydrophobic/hydrophilic groups introduced into the polymer chain grafted onto a porous membrane

Sawaki, Kenta*; Asai, Shiho; Watanabe, Kazuo; Sugo, Takanobu*; Saito, Kyoichi*

Maku, 33(1), p.32 - 38, 2008/01

http://ci.nii.ac.jp/naid/10020130502

TOPO, tri-n-octylphosphine oxide, as a neutral extractant was impregnated to the hydrophobic group of the polymer chain grafted onto a porous hollow-fiber membrane for an efficient metal-ion collection. A diol group,i.e., adjacent hydroxyl group was introduced into poly-glycidyl methacrylate(GMA) chain grafted onto the porous hollow-fiber membrane via the epoxy-ring-opening reaction with water, followed by a reaction of the remaining epoxy group with octadecanethiol (CHSH) to form an octadecanethiol group. The diol group reduced the amount of TOPO coagulatedon the graft chain, whereas the interaction of the octadecanethiol group of the graft chain with the hydrophobic part of TOPO enabled the impregnation of TOPO to the graft chain. A 1 mmol-Bi/L bismuth chloride solution was forced to permeate through the pores of the TOPO-impregnated porous hollow-fiber membrane with a density of TOPO impregnated of 1.3 mol/kg of the GMA-grafted porous hollow-fiber membrane and the pure water flux of 0.7 m/h at 0.1 MPa and 298 K. The equilibrium binding capacity of the membrane for bismuth ions was 0.22 mol/kg of the TOPO-impregnated porous hollow-fiber membrane, which was equivalent to a binding ratio of bismuth ion to impregnated TOPO of 1.0.

Preparation of extractant-impregnated porous sheets for high-speed separation of radionuclides

Ishihara, Ryo*; Umeno, Daisuke*; Saito, Kyoichi*; Asai, Shiho; Sakurai, Satoshi; Shinohara, Nobuo; Sugo, Takanobu*

Nihon Ion Kokan Gakkai-Shi, 18(4), p.480 - 485, 2007/10

https://doi.org/10.5182/jaie.18.480

Impregnation of an acidic extractant cyanex 272 to the alkylamino group and alkylthiol group introduced into the polymer chain grafted onto a porous membrane

Sawaki, Kenta*; Domon, Sayaka*; Asai, Shiho; Watanabe, Kazuo; Sugo, Takanobu*; Saito, Kyoichi*

Maku, 32(2), p.109 - 115, 2007/03

http://ci.nii.ac.jp/naid/10018865892

no abstracts in English

Preparation of an extractant-impregnated porous membrane for the high-speed separation of a metal ion

Asai, Shiho; Watanabe, Kazuo; Sugo, Takanobu*; Saito, Kyoichi*

Journal of Chromatography A, 1094(1-2), p.158 - 164, 2005/11

https://doi.org/10.1016/j.chroma.2005.07.095

The analysis of radioactive species in radioactive wastes is essential to the safe and economical disposal of such wastes. Among radioactive species, alpha- and beta-emitting nuclides should be purified prior to various radiometric determinations. To overcome the disadvantages of the conventional separation techniques, we have proposed functional porous hollow-fiber membranes that achieve a high speed operation assisted by convective flow. Stable immobilization in aqueous media is ensured by the hydrophobic interaction between the hydrophobic moiety of the extractant and octadecyl part of octadecylamino group. In this study, HDEHP, which shows the selectivity for rare earth elements, such as yttrium, was immobilized onto the porous membrane. The amount of immobilized HDEHP increased with increasing molar conversion. This can be explained by the fact that an increase in the CNH group allows the polymer brush to extend itself due to electrostatic repulsion originating from the amino part of the CNH group.

Production and setting of fractional elution facility for recovery of useful rare metals from seawater

Seko, Noriaki; Kasai, Noboru; Tamada, Masao; Hasegawa, Shin; Katakai, Akio; Sugo, Takanobu*

JAERI-Tech 2004-076, 78 Pages, 2005/01

JAERI-Tech-2004-076.pdf:17.11MB

In September 1999, we have soaked 200 kg of fibrous amidoxime adsorbents, synthesized by radiation-induced graft polymerization, into seawater to evaluate their performance. Fractional elution facility was set effectively to elute the rare metals on adsorbents in Mutsu-Establishment. This facility consists of two parts of pre-washing and elution. The present report dealt with planning, manufacture and setting of fractional facility. Marine organism and slime on adsorbent cassette (290290160 mm) were washed out and every 72 cassettes were set in elution unit (12101210H1460 mm) with nonwoven materials as a packing to avoid elution loss. In the elution process alkaline and alkaline earth metals were eluted with low concentration hydrochloric acid (0.01M) and rare metals were eluted with high concentration (0.5M) after the packing of elution unit into fractional elution facility.

Bifunctional cation exchange fibers having phosphoric and sulfonic acid groups

Jo, Akinori*; Okada, Kenji*; Tamada, Masao; Kume, Tamikazu; Sugo, Takanobu; Tazaki, Masato*

Chemistry for the Protection of the Environment 4; Environmental Science Research, Vol. 59, p.49 - 62, 2005/00

Bifunctional cation exchange fibers were synthesized by co-grafting of chloromethylstylene and styrene. on polyethylene-coated polypropylene fibers. The grafted fibers were fictionalized by Arbuzov reaction, suffonation, and acid hydrolysis. Batchwise evaluation of metal ion selectivity clarified that the bifunctional fiber exhibited cooperative recognition of metal ions by both functional groups. The bifunctional fiber took up Pb(II) more rapidly than the monofunctional phosphoric acid fiber and commercial resin adsorbent. Column-mode experiment revealed that flow rate was independent of break through profiles of Pb(II) up to flow rate of 900 h in space velocity.

Fibrous iminodiacetic acid chelating cation exchangers with a rapid adsorption rate

Jo, Akinori*; Kugara, J.*; Trobradovic, H.*; Yamabe, Kazunori*; Sugo, Takanobu; Tamada, Masao; Kume, Tamikazu

Industrial & Engineering Chemistry Research, 43(7), p.1599 - 1607, 2004/03

https://doi.org/10.1021/ie030146h

Fibrous iminodiacetic acid cheating cation exchangers were derived from chloromethylstyrene radiation-grafted polyethylene-coated polypropylene filamentary fiber and its nonwoven cloth. Ligand contents and acid capacities of the resulting cation exchangers were ca. 2 mmol/g and ca. 4 mmol/g for the filamentary fiber and for the non-woven cloth, respectively. The selectivity sequence of nonwoven cloth shape for dialect metal ions is Mg(II) Ca(II) Co(II) Zn(II) Cd(II) Ni(II) Pb(II) Cu(II). Capacities in mmol/g at pH 5 were Ca(II) 0.91, Mg(II) 0.98, Cd(II) 1.5, Ni(II) 1.5, Pb(II) 1.6, Cu(II) 1.8. Column mode for filamentary fiber shape revealed that breakthrough capacities for Cu(II) (ca. 1 mmol/g) were not dependent on flow rates up to 200 300 h in space velocity.

Aquaculture of uranium in seawater by a fabric-adsorbent submerged system

Seko, Noriaki; Katakai, Akio; Hasegawa, Shin; Tamada, Masao; Kasai, Noboru; Takeda, Hayato*; Sugo, Takanobu; Saito, Kyoichi*

Nuclear Technology, 144(2), p.274 - 278, 2003/11

https://doi.org/10.13182/NT03-2

The total amount of uranium dissolved in seawater at a uniform concentration of 3 mg-U/m in the world's oceans is 4.5 billion tons. An adsorption method using polymeric adsorbents capable of specifically recovering uranium from seawater is reported to be economically feasible. A uranium-specific non-woven fabric was used as the adsorbent packed in an adsorption cage. We submerged adsorption cages, 16 m in cross-sectional area and 16 cm in height, in the Pacific Ocean at a depth of 20 m at 7 km offshore of Japan. The cage consisted of stacks of 52,000 sheets of the uranium-specific non-woven fabric with a total mass of 350 kg. The total amount of uranium recovered by the non-woven fabric was more than one kg in terms of yellow cake during a total submersion time of 240 days in the ocean.

Recovery of cadmium from waste of a scallop processing with amidoxime adsorbent synthesized by graft-polymerization

Shiraishi, Tomoyuki*; Tamada, Masao; Saito, Kyoichi*; Sugo, Takanobu

Radiation Physics and Chemistry, 66(1), p.43 - 47, 2003/01

https://doi.org/10.1016/S0969-806X(02)00263-3

no abstracts in English