LANTHANUM UPTAKE BY CLAYS AND ORGANO-CLAYS: EFFECT OF THE POLYMER

Two natural smectite clays (STx-1b and SWy-2) were studied as solid sorbents for uptake and release of lanthanum. Since the obtained global efficiencies of lanthanum recovery were about 30-35%, the same considered natural clays were modified by intercalating a PEGylated ethylene diamine having chelating properties, in order to evaluate a possible improvement effect of the polymer. The pristine and the organo-clays were characterized by XRD analyses while the amounts of intercalated polymer and captured lanthanum were estimated respectively by COD and ICP-OES analyses. The results showed that pristine clays and modified clay had similar lanthanum uptake efficiencies while modified clays presented a better behaviour towards release processes, ensuring a recovery global efficiency of 43%.