Water uptake and dye sorption studies of chemically crosslinked highly swollen novel ternary acrylamide‐based hydrogels including citraconic acid and sodium acrylate

Highly swollen hydrogels made by the polymerization of acrylamide (AAm) with some anionic monomers such as citraconic acid (CITA) and sodium acrylate (SA) were investigated as a function of composition to find materials with swelling and dye sorption properties. Highly swollen AAm/CITA/SA or AAm/SA/CITA hydrogels were prepared by free radical solution polymerization in aqueous solutions of AAm with CITA and SA as co‐monomers and two multifunctional crosslinkers such as ethylene glycol dimethacrylate (EGDMA) and 1,4‐butanediol dimethacrylate (BDMA). Swelling experiments were performed in water at 25°C, gravimetrically. Chemically crosslinked AAm/CITA/SA or AAm/SA/CITA hydrogels were used in experiments on sorption of water‐soluble monovalent cationic dye such as “Nil blue” (Basic Blue 12; BB 12). Equilibrium percentage swelling values of AAm/CITA/SA or AAm/SA/CITA hydrogels were calculated in the range of 1797–22,098%. Some swelling kinetic parameters were found. Diffusion behavior of water was investigated. Water diffusion into the hydrogels was found to be non‐Fickian in character. For sorption of cationic dye, BB 12 into the hydrogels was studied by batch sorption technique at 25°C. AAm/CITA/SA or AAm/SA/CITA hydrogels in the dye solutions showed coloration, whereas AAm hydrogel did not show sorption of any dye from the solution. The sorption capacity of AAm/CITA/SA or AAm/SA/CITA hydrogels was investigated. At the end of the experiments, 21.70–78.91% BB 12 adsorptions were determined. Copyright © 2007 John Wiley & Sons, Ltd.