Sorption of lead(II) by proton-ionizable polyether resins

Novel ion-exchange resins have been prepared by condensation polymerization with formaldehyde of dibenzo acyclic and cyclic polyethers bearing a pendent acidic function (carboxylic acid, phosphonic acid monoethyl ester, phosphonic acid, or sulfonic acid). Such resins possess both ion-exchange and polyether-binding sites for metal-ion complexation. The efficiency of Pb^2- sorption and selectivity relative to Zn²⁺ sorption are assessed as a function of: (1) the acyclic, pseudocyclic, or cyclic nature of the polyether unit; (2) the identity of the proton-ionizable group; (3) the length of the spacer which joins the proton-ionizable group to the polyether framework; and (4) for the proton-ionizable crown ether resins, the atom or group which is geminal to the functional side arm.