Excessive use of chemicals, fertilisers, phenols, dyes, heavy metals, etc. leads to destroy our environment when discharged into water, air, and soil directly. These polluted substances imbalance our ecosystem by affecting all living things. Researchers and scientists are collectively working to invent different materials and techniques to eliminate these toxic materials or to decrease their side-effects. Recently, significant progress has been made in developing advanced materials such as, nanocomposites, polymer-based composites, and graphene-based nanomaterials. However, ion exchange materials, owing to their diverse properties including, electrochemical, physical, magnetic, and chemical characteristics, are highly selective and effective for the removal of such pollutants. The present book chapter focuses on basic introduction of ion exchange materials, biopolymer-based ion exchangers and their different environmental applications like removal of heavy metal ions, preparation of ion-selective electrode, photocatalysis, electrodialysis, etc.