Preparation and properties of sorbents using for concentration of radionuclides from aqueous solutions

Serious threats to the environment and organisms include pollutants, heavy metals, radionuclides and radioactive waste. They belong among the radiologically but also chemically dangerous substances. They enter the environment in many ways, such as nuclear energy, accidents at nuclear installations, nuclear medicine, military activities and many other means. Therefore, materials suitable for the removal of these hazardous substances are being sought. Alternative methods of radionuclide removal also include adsorption on materials of natural origin, their modification or on recycled waste materials. Hydroxyapatite as well as activated carbon prepared from waste rubber, or CA prepared on the base of cellulose, are materials suitable for removing radionuclides and heavy metals from aqueous solutions. These adsorbents have suitable functional surface groups which form bonds with dangerous radionuclides or pollutants. The aim of this work was to prepare sorption materials, namely hydroxyapatites modified with Sn²⁺ ions and activated carbons based on cellulose resp. CA prepared by pyrolysis from waste rubber. Their morphology and surface structure were examined by FTIR, XRD, XPS, XRF, SEM-EDS and TEM methods. The specific surface area of the materials was determined by the BET method and the pHPZC point was identified by acid-base titration resp. drift method. The adsorption experiments were performed under static conditions, while the effect of contact time, the effect of pH, the effect of competing cations and anions on the adsorption of ⁶⁰Co and ^99mTcO₄^- on adsorption materials was examined. Adsorption isotherm values were also determined using the Langmuir and Freundlich models. (author)