Effect of pH, and Salinity onto Swelling Properties of Hydrogels Based on H-alginate-g-poly(AMPS)

To following synthesis of a novel superabsorbent hydrogel based on alginate, the swelling of superabsorbing hydrogels was examined in solutions with pH values ranging between 1.0 and 13.0. It showed a reversible pH-responsive behavior at pHs 2.0 and 8.0. The swelling measurements of the hydrogels were also conducted in aqueous solutions of LiCl, NaCl, KCl, MgCl sub(2), CaCl sub(2), SrCl sub(2), BaCl sub(2), and AlCl sub(3). Results indicated that the swelling capacity decreased with an increase in the ionic strength of the swelling medium. Due to the high swelling capacity in salt solutions, the hydrogels may be referred to as anti-salt superabsrbents.