Selective Radioactive Decontamination employing Dual Stimuli Responsive N -Aza crown ether containing polymer hydrogels.
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1265-AA09-07
Selective Radioactive Decontamination employing Dual Stimuli Responsive N-Aza crown ether containing polymer hydrogels. Dario Deli1, David J. Crouch1, Kathleen Law2, Stephen G. Yeates1 and Francis Livens2 1 OMIC, University of Manchester, Oxford Road, Manchester, M139PL, UK 2 CRR, University of Manchester, Oxford Road, Manchester, M139PL, UK ABSTRACT We report the synthesis and properties of two different hydrogels based on Nisopropylacrylamide/acrylic acid and copolymers of oligo-ethylene glycol methacrylates incorporating N-Aza crown ethers. Both hydrogels show rapid response to environmental stimuli and their size can be tuned by pH and temperature. Swollen states lead to high adsorption of water and high contact surface area with ions whereas in the collapsed state the material releases water and the ions not selectively retained by the polymer (Figure 1). Preliminary autoradiography tests show that these materials strongly bind 90Sr and both pH and temperature can be used to fine tune binding selectivity. This results in such materials being promising candidates for use as smart scavenging agents for radioactive decontamination. TLCST
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N-Aza-crown ether
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: Different metal ions Thermo-responsive backbone
Figure 1: Scheme of selective adsorption and release of metals using a thermo-reversible gel. INTRODUCTION Radioactive decontamination of aqueous solutions has received increasing interest due to concerns over human health and environment with many studies focusing on new materials which strongly and selectively bind radionuclides.[1-4] Intermediate level fusion products such as 137Cs and 90Sr are considered the most environmentally hazardous radiotoxic elements [4-6] and also present a danger in low concentration when elements such as Ca2+, Na+, K+ are present in large quantities. Sequestering materials should, therefore, display high selectivity for the targeted radionuclide and low affinity for other stable elements in large excess. N-Aza-crown ethers have proved to selectively complex a wide range of metal ions;[7] however recovery after complexation is difficult due to their good solubility in various solvents. Additionally the stability of the complex can often be low.[8] Incorporation of these compounds into welldesigned polymers opens the way to novel sequestering agents for radiological decontamination.
Hydrogel beads are attractive as they can absorb large quantities of water allowing for hig
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