The Hydrogels and Their Novel Application

Hydrogels are 3-D (three-dimensional) polymers that when encountered with water do not dissolve but they get swell. The hydrogel swelling is different in various conditions and parameters such as temperature, pH, and ionic strength. They show different responses and specifies. Generally, hydrogels are produced by two methods chemical and radiation methods. Vinyl hydrogels are the most applicable ones by worldwide polyamorists', but, because of the rare existence of vinylamine, Poly(allylamine) gets important and is available. Interpenetrating polymer networks (IPN)) hydrogels can be prepared by Poly(allylamine) and used to absorb nitrophenols from wastewater. In recent years, Poly(allylamine) was produced using glutaraldehyde and epichlorohydrin as a cross-linker agent. The optimum amount of cross-linker was found to achieve the maximum swelling degree. UV–Vis spectroscopy was utilized to determine the dynamic change of the 4-nitrophenol concentration. The results revealed the complete absorption of the 4-nitrophenol pollutant. They suggest the prepared semi-IPN hydrogel is an appropriate system for treating wastewater