부산대학교 도서관

Coprecipitation of 233U, 239Pu, 241Am, 152Eu, 90Sr, 90Y, and 60Co on chitosans of various molecular weights (MW) was studied. Low-molecular-weight chitosan (LMWC) with MW of 5 kDa (5 × 103 g mol−1) proved to be a more effective coprecipitant than high-molecular-weight chitosan (HMWC) with MW of 700 kDa (7 × 105 g mol−1). With HMWC, the degree of coprecipitation (α) was 80% for 152Eu and 90Y, 99% for 233U and 241Am, and 85% for 239Pu. For 60Co, α monotonically increased with an increase in the chitosan concentration in solution and reached 40% at [HMWC] = 5 g l−1. For 90Sr, α did not exceed 3% in the entire examined range of chitosan concentrations. With LMWC, the α values for An, 152Eu, and 90Y differed insignificantly (92–99%). For 60Co and 90Sr, α increased to 40% in the range of chitosan concentrations from 0 to 1 g l−1. The presence of inorganic salts in solution considerably decreases α of UO with chitosans but does not noticeably affect the behavior of Am, Pu, and Eu. The effect of salts on the efficiency of 233UO2/2+ coprecipitation on HMWC decreases in the order Na2SO4 > NaCl > Na2CO3 > NaNO3 > Na3PO4. Based on the results obtained, a procedure suitable for expedition conditions was developed for preconcentration of Pu from seawater on chitosan, with simultaneous separation of Pu from U, for radioecological monitoring of natural waters. The specific activity of Pu in samples of near-bottom seawater of gulfs of the Novaya Zemlya archipelago was (150–170) ± 20 mBq m−3. The results are well consistent with the published data. [ABSTRACT FROM AUTHOR]