Cd(II)Extraction in PEG-based two-phase aqueous systems in the presence of iodide ions. Analysis of PEG-rich solid phases

摘要

Cd(II)plus iodide species were extracted into PEG-rich phases in the aqueous PEG(1550)- (NH4)2SO4 system at pH 2.05-7.12.IR spectra show that increasing(NH4)2SO4 solution acidity does not protonate PEG ether oxygen atoms,but decreases water content in the PEG-rich phases.Metallic species'extraction into the PEG predominantly alters how water molecules bind to polymer chains;the changes in their absorption bands depend on pH.Microscopy shows that"fixation"of the extracted metal in the PEG-rich phase occurs by specific interactions which depend on the species.These also determine changes in the polymer chains'conformation.