Highly selective separation of pertechnetate from waste water

Abstract

This work addresses the challenging problem of separating pertechnetate (TcO4−) ions from huge (˜1010 times) NO3− background, which is very important for nuclear waste water treatment. It describes the facilitated transport based selective removal of 99mTcO4− from aqueous feed solutions through a Tetraphenylarsonium perchlorate loaded polypropylene based supported liquid membrane. Keeping in mind the possible aqueous waste compositions in the nuclear industry, the transport selectivity of 99mTcO4− has been studied in the presence of varying concentrations of NO3−, CO32- and OH− ions. As NO3- is the major anion in aqueous nuclear waste solutions, major importance has been given to study the selectivity of 99mTcO4− over NO3−. The transport selectivity has been studied using radiotracer technique as well as ion chromatography technique. Results indicate that the membrane is highly selective towards 99mTcO4− considering even high concentration of NO3− does not hinder its transport appreciably. High decontamination factor for 99mTcO4− over NO3- and other anions has been obtained in all the cases. The promising results show the possibility of using this membrane-based fast process for nuclear waste treatment.