Impregnated Type Sorbents for Pb2+ Recovery from Neutral and Acidic Solutions

Abstract

Synthetically convenient method for preparing phosphoryl podand 1,8-bis[2-(diphenylphosphorylmethyl)phenoxy]-3,6-dioxaoctane (L) has been developed. Recovery of Pb2+ with impregnated type sorbents was studied, the sorbents contain isodentate organic ligands—phosphoryl podand L and crown ether (4,4',(5')-di(tert-butyl)dicyclohexyl-18-crown-6)—as extractants. A sorbent based on the phosphoryl podand quantitatively extracts lead from neutral solutions (R = 98.4%) and does not recover it from acid solutions. On the contrary, the sorbents based on 4,4',(5')-di(tert-butyl)dicyclohexyl-18-crown-6 do not extract lead from neutral media and efficiently adsorb it from nitric and hydrochloric acid solutions (R = 90% from 3 M nitric acid solutions and R = 73.2% from 2 M hydrochloric acid solutions). Effect of diluent and support type, support pretreatment procedure, impregnation temperature and time, and solvent for support impregnation on lead sorption with sorbents based on 4,4',(5')-di(tert-butyl)dicyclohexyl-18-crown-6 have been studied.