A review on environmental applications of polymer hydrogels and their composites

Hydrogels are hydrophilic polymeric network of three dimensional cross linked structures that absorb substantial amount of water. Cross linking facilitates insolubility in water because of physical or chemical bonding. It also provides required mechanical strength and physical integrity to the hydrogels. There is an emerging demand and expanding interest in synthesis of hydrogel materials such as hydrogel based membranes and hydrogel composites. They can be applied in industrial separations, agriculture, biomedical purposes and reduction in environmental toxicity because of their good sorption abilities, resistance and low cost. Environmental degradation has a great impact on human health. Preventive measures taken to protect our environment will largely help in reducing illness and adverse health conditions. Research and advanced studies to understand various environmental issues, which have been plaguing us from a long time now, are looked up to with intense interests. The understanding of the causes and possible solutions for environmental problems calls for good sensors, to identify various causalities. Hence, a significant section on hydrogels used in sensing for environmental applications is presented here. With mounting issues of water scarcity and water pollution, recent applications of hydrogels for water remediation is also an important environmental application that we have addressed.