Extraction of radionuclides using different adsorbents from contaminated water: review

The presence of toxic metal ions in the water is a problem due to their acute and long term toxicity. Water is contaminated due to industrial effluents discharges in water bodies viz. pesticides, batteries, alloys, electroplated metal parts, mining, refining and production of textiles, paints and dyes industries. Most of the radionuclides in drinking water occur naturally at very low levels and are not considered a public health concern. However, water gets contaminated with radionuclides during accidents in nuclear power plants, research facilities and the use of radioisotopes in industry and diagnostic medicine produce a wide variety of radioactive wastes. The major contaminants are long lived radionuclides viz. cesium, strontium and their degraded products. Drinking water contaminated with radionuclides will be a severe threat to military as well civilian population. Such events have occurred in Japan and Chernobyl due to the earthquake, industrial accident respectively. Some radionuclides viz. uranium, thorium and actinium are found in rocks. These rocks may transmit radionuclides into drinking water. High level of these radionuclides tends to be found in ground water viz. tube wells. Therefore, extraction of radionuclides from water is a necessary requirement. Defence Laboratory, Jodhpur has developed adsorbent for removal of toxic metal ions viz. Functionalized silica, functionalized MWCNTs, Ag@Al₂O₃, zeolites, composite hydrogel and evaluated for removal of radionuclides. Now our R & D is focusing on development resins/adsorbents for removal of radionuclides from contaminated water