Poly (Acrylamide-co-Acrylic Acid) Hydrogel Induced by Glow-Discharge Electrolysis Plasma and Its Adsorption Properties for Cationic Dyes

In this paper, poly (acrylamide-co-acrylic acid) (P(AM-co-AA)) hydrogel was prepared in an aqueous solution by using glow-discharge electrolysis plasma (GDEP) induced copolymerization of acrylamide (AM) and acrylic acid (AA), in which N,N'-methylenebisacrylamide (MBA) was used as a crosslinker. A mechanism for the synthesis of P (AM-co-AA) hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail: the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0-10.0. The P(AM-co-AA) hydrogel exhibits a very high adsorption potential and the experimental adsorption capacities for Crystal violet (CV) and Methylene blue (MB) were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P(AM-co-AA) hydrogel for cationic dyes was also discussed.