Preparation and characterization of a polyacrylamide resin containing thiol groups. Study of the reversible Zn(II) fixation

New resins (6) containing thiol groups within a hydrophilic matrix are described. They contain up to 3,6 mmol thiol groups per g of dry polymer and were prepared by thiolation, via thiolester group formation, of various crosslinked polymers of N-acryloylaminomethylchloroacetamide (1c) which was synthetized. Their ability to extract Zn(II) ions was evaluated. The effects of contact time, pH, and complexing agents on the fixation reaction were studied. It was found that the equilibrium is reached in a few minutes, the optimal capacity at pH 6 being about 2 mmol Zn(II) per g. The fixation involves three reactions: two leading to thiol group complexation, the third being the retention by the amide function of the resin saturated with Zn(II).