Binding of uranyl ion by 2,2?-dihydroxyazobenzene attached to a partially chloromethylated polystyrene

Abstract

A 2,2′‐dihydroxyazobenzene (DHAB) derivative was attached to a chloromethylated cross‐linked polystyrene derivative in view of high affinity of DHAB for uranyl ion. Chloromethyl groups of the resin were converted to quaternary ammonium ions by treating with tertiary amines. Capacity of the resins for uranyl‐uptake was measured, revealing that about 20 mg of uranium can be complexed to 1 g of the resins. Formation constants (Kf) for uranyl complexes of the resins were determined. In the presence of >0.1 M bicarbonate ion at pH 8.10, log Kf of about 15 was obtained. As bicarbonate concentration was lowered, Kf decreased considerably. Degrees of uranyl‐uptake from rapidly flowing uranyl solutions were measured, and the results suggested that rate of uranyl‐uptake may not impose a major barrier to application of the resins in uranium extraction from seawater. Uranium extraction from seawater with the resins was carried out on the east coast of Korean peninsula. The amount of uranium extracted from seawater was about 10 µg/g resin. This is not satisfactory for economical processes of uranium recovery from seawater. Results of the present study, however, suggested that modification of the DHAB‐containing resins can improve uranyl‐binding ability, probably leading to economical recovery of uranium from seawater. In addition, simulation of uranyl‐binding processes in seawater with the laboratory procedures developed in this study was satisfactory. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3169–3177, 1999

Materials for the Recovery of Uranium from Seawater

“…Suh and colleagues functionalized Sephadex G-25 resin with a metal-binding ligand composed of 2,2′-dihydroxyazobenzene (DHAB) attached to poly­(ethylenimine) (PEI; Figure ). This work followed previous studies by the same group where DHAB was attached to a chloromethylated cross-linked poly­(St) support, chloromethylated poly­(St- co -DVB), and pure PEI . In the former references, the chloromethyl group could also be converted to a quaternary ammonium function by treating with various tertiary amines. , In this work, spectrophotometric titration experiments revealed 1:1 complexes of various metals, including uranium, with PEI-bound DHAB (Figure ).…”

“…This work followed previous studies by the same group where DHAB was attached to a chloromethylated cross-linked poly­(St) support, chloromethylated poly­(St- co -DVB), and pure PEI . In the former references, the chloromethyl group could also be converted to a quaternary ammonium function by treating with various tertiary amines. , In this work, spectrophotometric titration experiments revealed 1:1 complexes of various metals, including uranium, with PEI-bound DHAB (Figure ). After grafting to the Sephadex resin with cyanuric chloride as a coupling reagent, the adsorbent was investigated for recovery of metals from seawater.…”

“…Noteworthy results from Korea from 1999 to 2000 articulated the postsynthetic installation of a cationic site within the adsorbent polymer, advantageous from the perspective of increasing hydrophilicity, facilitating mass transport through Coulombic repulsion-induced swelling of graft chains, and promoting electrostatic concentration of the anionic UO 2 (CO 3 ) 3 4– in seawater. − …”