Adsorption of some basic dyes by acrylamide-maleic acid hydrogels
In this study, acrylamide-maleic acid (AAm/MA) hydrogels containing different quantities of maleic acid have been irradiated with gamma-radiation. They have been used in experiments on swelling, diffusion, and the adsorption of basic dyes such as methylene blue, methyl violet, and nile blue. Acrylamide-maleic acid hydrogel containing 40 mg maleic acid and irradiated at 3.73 kGy has been used for swelling and diffusion studies in water and solutions of basic dyes. For this hydrogel, maximum and minimum swellings have been observed with solutions of nile blue (2000% swelling) and water (1480% swelling). Diffusions of water and dyes within hydrogels have been found to be non-Fickian in character. In experiments on the adsorption of dyes, Type III adsorption has been found. One gram of AAm/MA hydrogel sorbed 0.3-2.2 mg of methylene blue, 0.3-3.4 mg of methyl violet, and 1.6-3.9 mg of nile blue, while acrylamide hydrogel has not sorbed any basic dye. This result shows that AAm/MA hydrogel can be used as a sorbent for water pollutants such as dyes, and immobilization of these organic contaminants in the hydrogels from wastewater can solve one of the most important environmental problems of the textile industry.