A new composite sorbent for water and dye uptake: Highly swollen acrylamide/2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid/clay hydrogels crosslinked by 1,4‐butanediol dimethacrylate

A novel type of highly swollen hydrogels based on acrylamide (AAm) with 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) and clay such as bentonite (Bent) crosslinked by 1,4‐butanediol dimethacrylate (BDMA) was prepared by free radical solution polymerization in aqueous media. Water uptake and dye sorption properties of polyelectrolyte AAm/AMPS hydrogels and AAm/AMPS/Bent composite hydrogels were investigated as a function of composition to find materials with swelling and sorption properties. FTIR analyses were made. Swelling experiments were performed in water and dye solution at 25°C, gravimetrically. Highly swollen AAm/AMPS and AAm/AMPS/Bent hydrogels were used in experiments on sorption of water‐soluble monovalent cationic dye such as Lauths violet “LV, (Thionin).” Swelling of AAm/AMPS hydrogels was increased up to 1,920–9,222% in water and 867–4,644% in LV solutions, while AAm hydrogels swelled 905% in water and swelling of AAm/AMPS/Bent hydrogels was increased up to 2,756–10,422% in water and 1,200–3,332% in LV solutions, while AAm/Bent hydrogels swelled 849% in water. Some swelling kinetic and diffusional parameters were found. Water and LV diffusion into hydrogels was found to be non‐Fickian in character. For sorption of cationic dye, LV into AAm/AMPS and AAm/AMPS/Bent hydrogel was studied by batch sorption technique at 25°C. The amount of the dye sorbed per unit mass removal effiency and partition coefficient of the hydrogels was investigated. The influence of AMPS content in the hydrogels to sorption was examined. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers