Synthesis, characterization, and property testing of PGS/P(AMPS-co-AM) superabsorbent hydrogel initiated by glow-discharge electrolysis plasma

Abstract

A palygorskite/poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylamide) (PGS/P(AMPS-co-AM)) superabsorbent hydrogel was prepared in aqueous solution using glow-discharge electrolysis plasma (GDEP) as an initiator and N,N′-methylene-bis-acrylamide as a cross-linker. A possible copolymerization mechanism initiated by GDEP was proposed. The structure, thermal stability, and morphology of PGS/P(AMPS-co-AM) were characterized by FT-IR, XRD, TG-DTG, and SEM. The swelling kinetics, pH-reversibility, and influence of various pH and salt solutions on the swelling were investigated. Adsorption kinetics and adsorption mechanism of hydrogel for dyes were studied in detail. The results indicated that the equilibrium swelling of hydrogel is 652.6 g g−1 in distilled water. The swelling of the hydrogel in salt solutions from highest to lowest is Na+ > Mg2+ > Fe3+. The hydrogel has pH-reversibility responsive to the pH and salts solutions. The adsorption process of dyes follows the pseudo-second-order kinetic model with multi-step diffusion process. In addition, PGS/P(AMPS-co-AM) hydrogel can be regenerated and reused.