The role played by the polymeric matrix structure in activation of polyacrylamide hydrogels containing Ni(II) for oxidation of the sulfide anion by molecular oxygen

The oxidation of the sulfide anion by oxygen was studied in the presence of nonhydrolyzed and hydrolyzed hydrogels containing Ni(II) and solutions of NiCl2. An initial increase in the absolute catalytic activity (event/s per Ni atom) by 80-140% was only observed for gel systems. The effect and its d ependence on the concentration of the active phase and the stability of cat alyst operation and catalyst aging are influenced by the size (volume) of t he cell of the three-dimensional polymeric network, which depends on the li miting swellability in syneresis.