Recovery of uranium by tannin immobilized on agarose

Tannin, which is a ubiquitous and inexpensive material, was immobilized on agarose gel to produce an excellent adsorbent for uranium recovery from seawater. Optimal conditions for the immobilization of tannin on agarose gel by both the epichlorohydrin and cyanuric chloride coupling procedures were examined in detail. The resulting immobilized tannin has a highly selective ability to adsorb uranium and applicability in both column and batch systems. This adsorbent can recover uranium from natural seawater with high efficiency. The maximum adsorption capacities were 1850 μg uranium g-1 adsorbent for the tannin immobilized on agarose gel by the epichlorohydrin coupling procedure and 1062 μg g-1 adsorbent for that produced by the cyanuric chloride coupling procedure. (author)