The long-lived radionuclides in radioactive waste have been considered to be dangerous pollutants, and their migration with groundwater is strongly affected by adsorption on the geologic materials. The presence of radionuclides and toxic metals in wastes is a major environmental concern. Such wastes arise from technologies producing nuclear fuels, and from laboratories working with radioactive materials. Various treatment technologies have been developed for the removal of heavy metals from water. The commonly used technologies for removing metal ions from effluents include chemical precipitation, lime coagulation, ion exchange. Synthetic organic–inorganic composite cation-exchange materials have received a great deal of attention because of their stability and reproducible analytical and electroanalytical applications. Organic polymers of composite material provide the mechanical strength and increase the surface area for more available exchangeable sites of the inorganic part. Nano composites of organic–inorganic cation-exchange materials prepared by sol–gel method are advance class of materials that are expected to provide many possibilities.