Competetive transport of cobalt-60, strontium-90, and cesium-137 radioisotopes across polymer inclusion membranes with DNNS

Plasticized cellulose triacetate membranes with 3,7-dinonyl-naphtalene-1-sulfonic acid (DNNS) containing o-nitrophenyl pentyl ether (ONPPE) as the plasticizer were prepared for competitive transport of Cs-137, Sr-90, and Co-60 isotopes from aqueous solutions at concentration of 1.0 × 10−7 M each and containing 0.10 M sodium nitrate. The receiving phase was 1.0 M HCl aqueous solution. The selectivity order of metal ions transported was found to be: Co(II) > Cs(I) > Sr(II). For optimal values of polymer inclusion membrane, i.e. 4.0 cm3 per 1.0 g cellulose triacetate the recovery factors for Co(II), Cs(I), and Sr(II) after 72 h of transport were found to be 98%, 91% and 51%, respectively. The long term integrity of transport across polymer inclusion membrane was studied. To explain the mechanism of membrane transport the diffusion of metal ions complexes with DNNS in polymer inclusion membrane was also measured.