A superabsorbent hydrogel for removal of dyes from aqueous solution

The removal of dye pollutants from dyeing and printing industrial wastewater is a very important issue, and different methods have developed for this purpose. Here, a hydrogel adsorbent gelatin/chitosan/β-cyclodextrin/sodium humate (GEL/CS/β-CD/SH) was developed by a simple method for removal of the reactive dyes in aqueous solutions. The hydrogel used as an adsorbent had a good adsorption to different kinds of organic dyes. In this work, we focused on the adsorption process of GEL/CS/β-CD/SH hydrogels to the cationic dyes methylene blue (MB) and anionic dyes acid fuchsin (AF), which are commonly used in the printing and dyeing industry. The effects of dye solution pH, ionic strength, temperature, and contact time were investigated in a batch system. The adsorption thermodynamic and dynamic behaviors towards AF and MB were investigated in detail. The adsorption process could occur spontaneously at environmental temperature. The results indicated that the maximum adsorption capacity of AF and MB reached 1666.7 mg/g and 714.3 mg/g, respectively. Moreover, the GEL/CS/β-CD/SH hydrogel could be degraded completely by microorganisms in the soil. Therefore, GEL/CS/β-CD/SH hydrogel has a potential application as an effective adsorbent for the treatment of dyeing wastewater.