Preparation and characterisation of acrylamide/maleic acid hydrogel

Acrylamide/maleic acid hydrogel, a superabsorbent polymer, was prepared by free radical polymerization in aqueous solution of acrylamide (AAm) and maleic acid (MA) : monomer and comonomer, respectively. Potassium persulfate and N,N,N’,N’-tetramethylethylenediamine were used as an initiator system. Also, ethylene glycol dimethacrylate (EGDMA) and N,N’-methylenebisacrylamide (MBA) were used as crosslinkers. Different compositions of acrylamide, maleic acid and crosslinkers were employed. Water swelling, equilibrium water content and swelling power of the hydrogel formed were determined. The result showed that the swelling in water at equilibrium of hydrogels was in the range of 8,420-10,300% and 3,160- 3,560%, equilibrium water content was in the range of 0.9880-0.9902 and 0.9630-0.9727 and swelling power was in the range of 84-103 and 31-36 using 1%EGDMA and 1%MBA as crosslinkers, respectively. The diffusion of water into hydrogel followed non-Fickian character based on swelling power

Synthesis and characterization of acrylamide/acrylic acid hydrogel and its application for crystal violet dye adsorption

Acrylamide/acrylic acid (AAm/AAc) hydrogel was prepared by free radical polymerization in aqueous solution of acrylamide and acrylic acid as a comonomer using ammonium persulfate and N,N,N’,N’-tetramethylethylenediamine as an initiator system and N,N’-methylenebisacrylamide as a crosslinker at room temperature. The hydrogels were prepared from acrylamide/acrylic acid with the ratios of 2.5/97.5, 5/95, 10/90, 20/80, 30/70, 40/60 and 50/50. The swelling property and the equilibrium water content of the hydrogel were determined in distilled water and in a solution of pH 3, 5, 7 and 8 for 96 hours. The result showed that the maximum swelling and equilibrium water content of the hydrogel obtaining from AAm/ AAc in the ratio of 10/90 were found to be 3,945% and 0.9747 at pH 8, respectively. The adsorption capacity of AAm/AAc (10/90) for crystal violet was also investigated at pH 3, 5, 7, 8 and 9 for 48 hours. It was found that the optimum adsorption capacity of the hydrogel was in the range of 5-8. The adsorption rate was 90% of the sorption completion within 48 hours. The equilibrium data fitted well to the Langmuir isotherm with the maximum adsorption capacity of 116.28 mg/g at pH 7