Hyperfiltration studies. III. Effect of certain metal ions on the salt filtration properties of cellophanes

Abstract
The salt rejection properties of cellophanes are substantially increased, and permeation rates decreased, by pretreatment with certain metal ions or presence of these ions at low concentration in feed solutions. In a typical case, a cellophane which initially rejected about 20% of salt from a 0.05M NaCl solution rejected over 70% in Presence of 10−3M ThCl4. Permeation rates were decreased, usually be a factior of 2 or 3. Additives found to have a marked effect were Fe(III), Th(IV), U(VI), Cu(II), and hydrolyzed pb(II). Mg(II), Ba(II), La(III), and unhdrolyzed Pb(II) had little effect. The mechanism by which the additives affect the cellophane is not clear.
Keywords