Nanotechnology and nanomaterials

Fabrication of nancomposite polymer granules for enhanced removal of cesium radionuclides 
Bondar Yu.V.1, Kuzenko S.V.1, Melnyk A.K.2
1State Institution “The Institute of Environmental Geochemistry of National Academy of Sciences of Ukraine”, 34a Palladin ave., 03142 Kyiv, Ukraine. 
E-mail:juliavad_peremoga@ukr.net
2Institute for Sorption and Endoecology Problems of National Academy of Sciences of Ukraine, 13 Naumov str., 03164 Kyiv, Ukraine.

The selective removal of cesium radionuclides from contaminated natural waters and technological effluents is an important issue to ensure radiation safety. Adsorption is considered the most effective and economical method for the purification of aqueous solutions from radionuclides. The insoluble metal hexacyanoferrates (HCFs) are considered as highly selective inorganic adsorbents for cesium ions. Unfortunately, HCFs are usually synthesized as ultrafine particles, which cannot be directly employed in adsorption systems owing to their quick agglomeration, compaction, loss of chemical activity and difficulties in the used adsorbent removing from the purified solution. The last achievements in nanotechnology allow overcoming these technical drawbacks through the synthesis of nanocomposite adsorbents.
A novel nanocomposite adsorbent based on commercially available macroporous polystyrene resin with sulfonic acid groups was successfully prepared by in situ formation of potassium-copper hexacyanoferrate phase inside the polymer granules. Results of X–ray diffraction and scanning electron microscopy studies confirm the formation of potassium-copper hexacyanoferrate phase on/inside the surface of polymer granules in the form of rounded nanoscale aggregates.
The efficiency of the synthesized nanocomposite adsorbent for removal of cesium ions was evaluated under various experimental conditions. It was demonstrated a rapid adsorption, high adsorption capacity over a wide pH range, and selectivity in Cs ion removal from model solutions with high content of competing sodium ions.
The synthesized nanocomposite adsorbent could find a large-scale application to treatment of low level liquid radioactive waste because of high selectivity to cesium ions, simplicity, environmentally friendly and low cost of synthetic method used.