Separation of 99 Tc from low level radioactive liquid waste using hollow fiber supported liquid membrane: optimisation and performance evaluation

Low level radioactive liquid waste (LLW) obtained after treatment of Intermediate level radioactive waste (ILW) is highly alkaline and rich in 99 Tc as the pertechnetate ion. It is considered as a long-term hazard in nuclear waste disposal. Solvent extraction of Pertechnetate species was performed using crown ether impregnated hollow fibre membrane using nitrobenzene and TBP solvents in different membrane modules. Better D values were obtained with Nitrobenzene however in view of toxicity of nitrobenzene study was also conducted with TBP and TBP nitrobenzene mix solvent. With nitrobenzene solvent almost 95% of 99 Tc was separated in four contacts. However with increase in TBP content the percentage extraction is decreasing due to decrease in D value. The results are presented and discussed in the paper.