Radiation synthesis and application of a hydrogel based on acrylic acid and 2‐mercaptobenzimidazole

Abstract

Abstract A hydrogel based on gamma‐radiation polymerization of acrylic acid (AAc) in the presence of 2‐mercaptobenzimidazole (MBI) and a crosslinking agent was prepared. The properties of this AAc/MBI hydrogel were characterized in terms of gel content, swelling in different solvents, structure morphology, and IR spectroscopy. Moreover, the thermal decomposition behavior of the prepared hydrogel was investigated by thermogravimetric analysis (TGA). The TGA thermograms were also used to determine the different kinetic parameters such as order of reaction and activation energy. The sorption of some divalent metal ions such as Cu 2+ , Pb 2+ , Cd 2+ , and Hg 2+ by the AAc/MBI hydrogel also was studied. The results showed that the AAc/MBI hydrogel has a higher tendency to swell in water and polar solvents than in nonpolar solvents. The highest metal uptake by the hydrogel was found for Hg 2+ and Cd 2+ , whereas the lowest was for Cu 2+ and Pb 2+ ions. The ratios between the distribution coefficients of the different metals [separation factors (SF)] indicate that the hydrogel has a high selectivity for Hg 2+ over Cu 2+ (SF = 10.923) and Pb 2+ (SF = 19.110). However, the hydrogel prefers Hg 2+ over Cd 2+ (SF = 1.356) and showed a high selectivity for Cd 2+ over Cu 2+ (SF = 7.822) and Pb 2+ (SF = 7.240). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1607–1614, 2002