Sustainable hydrogels as an emerging material platform for water purification

Hydrogels are materials of considerable interest because of their extensive applications in many fields and are effective adsorbent materials; because of their porous nature and three-dimensional network, they hold a large amount of water and are thus used effectively to absorb moisture contents in any particular system. Hydrogels also function as effective adsorbent materials and are used in various techniques such as electrophoresis, proteomics, and chromatography as support materials for various catalysts and in providing water to plants in the regions where water content is not enough for the proper growth of plants. Utilizing this three-dimensional porous network of hydrogels, their applications have been extended to water purification. Hydrogels effectively remove water pollutants by physical and chemical methods. Adsorption is the most common phenomenon exhibited by hydrogels. Wastewater contains a large number of pollutants from various sources. The food industry is the largest contributor to introducing carcinogenic colored compounds in the form of dyes in water bodies. Water is continuously being filthy, diseased, contaminated, and unhygienic because of a large number of wastes that enter the water bodies without any treatment; this waste includes a large number of organic and inorganic pollutants. Therefore, it becomes necessary to treat this wastewater and the resulting contaminated water to cope with the clean water demands and the depleting water resources. Among them, dyes are well-known toxic and carcinogenic pollutants in wastewater. Photocatalytic degradation of wastes is the most effective process in the degradation of carcinogenic dyes, and heterogeneous catalysis occupies the central core of photocatalytic degradation of dyes.