URANIUM UPTAKE DURING PERMEATION OF SEAWATER THROUGH AMIDOXIME-GROUP-IMMOBILIZED MICROPORES

The polymer chains containing an amidoxime (AO) group capable of speci fically collecting uranium in seawater were grafted onto a microporous hollow-fiber membrane. Crosslinking of the grafted polymer branches b y bivalent ions such as Mg and Ca ions in seawater permitted permeatio n of seawater through the AO-group-immobilized micropores. The logarit hm of the ratio of uranium concentration at the outlet to that at the inlet linearly decreased with an increasing residence time of seawater across the AO hollow-fiber membrane, which indicates that the chelate formation of the AO group immobilized on the microporous membrane wit h uranyl species governed the overall uranium uptake rate.