Sorption of Metal Ions from Aqueous Solutions by Crown Ethers

The sorption of copper and lead ions by polymeric sorbents based on crosslinked polyacrylamide containing chemically bound or immobilized 15-crown-5 and 18-crown-6 was studied, as was the effect of various parameters on the efficiency of metal sorption from aqueous solutions. It is shown that the sorption capacity of these sorbents increases dramatically with an increase in the content of crown ethers in them from 3 to 6 wt %. When aging sorbents containing 6 wt % 15-crown-5 or 18-crown-6, in an aqueous solution of copper chloride or lead acetate, respectively, the salt concentration in the solution decreases by 3-4 orders of magnitude. When aging sorbents based on 18-crown-6 in a solution containing equivalent amounts of lead acetate or copper sulfate, the amount of absorbed copper did not exceed 5% of the amount of extracted lead, which indicates the high selectivity of such sorbents.