Novel elastic gel was obtained by immersing paste of sodium carboxymethylcellulose (CMC) in acid solution. The paste was prepared by mixing CMC and water at the concentration of 20%. Water absorption and mechanical strength of the resultant gel were evaluated after removing uncrosslinked CMC and acid. Combination of radiation crosslinking and the immersion in acid resulted precise molding and dimension stability of the gel. Maximum mechanical strength of the gel at 50% compression increased with acid concentration for the unirradiated and the irradiated samples at 5-20kGy. The gel prepared by irradiation at 5-lOkGy and the immersion did not cause rupture after 50% compression and was more than 100 times stronger than the radiation-crosslinked gel. The reason of the mechanical strength was attributed to crosslinks formed by the acid treatment The crosslinks by the irradiation had been referred to chemical bonds, whereas, those by acids were caused by hydrogen bonds, which was elucidated by FT-IR, ICP and TG-DTA measurements. Sodium in the carboxymethyl groups is replaced by hydrogen in the acid solution. The hydrogen bonds induced the decrease of CMC solubility in water and formed the elastic gel.

A nonwoven fabric adsorbent loaded with 2-ethylhexyl hydrogen-2-ethylhexylphosphonate (EHEP) was developed for the separation and recovery of dysprosium (Dy) and neodymium (Nd) from an aqueous solution. The adsorbent was prepared by the radiation-induced graft polymerization of a methacrylate monomer with a long alkyl chain onto a nonwoven fabric and the subsequent loading of EHEP by hydrophobic interaction and chain entanglement between the alkyl chains. The adsorbent was evaluated by batch and column tests with a Dy (III) and Nd (III) aqueous solution. In the batch tests, the adsorbent showed high Dy (III) adsorptivity close to 25.0 mg/g but low Nd (III) adsorptivity below 1.0 mg/g, indicating that the adsorbent had high selective adsorption. In particular, the octadecyl methacrylate (OMA)-adsorbent showed adsorption stability in repeated tests. In the column tests, the OMA-adsorbent was also stable and showed high Dy (III) adsorptivity and high selectivity in repeated adsorption–elution circle tests. This result suggested that the OMA-adsorbent may be a promising adsorbent for the separation and recovery of Dy (III) and Nd (III) ions.

A chelating fabric was prepared by graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven fabric, followed by attachment reaction of N-methyl-D-glucamine (NMDG) using an organic solvent-free process. The graft polymerization was performed by immersing the gamma-ray pre-irradiated fabric into the GMA emulsion, while the attachment reaction was carried out by immersing the grafted fabric in the NMDG aqueous solution. The chelating capacity of the chelating fabric prepared by reaction in the NMDG aqueous solution without any additives reached 1.74 mmol/g, which further increased to above 2.0 mmol/g when surfactant and acid catalyst were added in the solution. The boron chelation of the chelating fabric was evaluated in a batch mode. Fourier transform infrared spectrophotometer (FTIR) was used to characterize the fabrics. The chelating fabric can quickly chelate boron from water to form a boron ester, and a high boron chelating ability close to 18.3 mg/g was achieved in the concentrated boron solution. The chelated boron can be eluted completely by HCl solution. The regeneration and stability of the chelating fabric were tested by 10 cycles of the chelation-elution operations. Considering the organic solvent-free preparation process and the high boron chelating performance, the chelating fabric is promising for the boron removal from water.

One of the most important tasks for recovering living area contaminated by the accident at the Fukushima Daiichi Nuclear Power Station is to secure a safe water supply. Therefore, we developed a Cs adsorbent wherein ammonium 12-molybdophosphate (AMP) was loaded by radiation-induced graft polymerization on aˆbrous trunk material and crosslinked to form a structure wherein the loaded AMP is stable. To optimize the synthesis of this Cs adsorbent, a 9G (G: dimethacrylate) polyethylene glycol dimethacrylate (PEGDM) was used as a crosslinking reagent and the adding volume was adjusted to 1 mol in a monomer solution to synthesize the Cs adsorbent with a 200 degree of grafting.Our evaluation of the adsorption performance of the Cs adsorbent indicates that it can be applied to a standard pH range for drinking water (from pH 5.8 to 8.6) and captures su‹cient Cs, even in a solution containing 1 mg/L of K, Ca, Mg, and Na ions, to yield a Cs concentration comparable to that of stream water.

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