Study on Sorption and Separation of Plutonium from Radioactive Waste Liquid by Radiation-resistant Fungi

The remediation of radioactive contamination in a quick, effective and economic mode is an important content in the field of nuclear emergencies and restoration of contaminated sites. In this paper, three kinds of radiation-resistant fungi, i.e. F3, F7 and F16, were separated and screened from a radioactive contaminated soil, and their soprtion performance for plutonium in aqueous solution was investigated. The results show that the three kinds of fungi have high sorption rate in pH=0.0-4.2 aqueous solution and increase with pH. At pH=1.0, 10 ng/mL plutonium in the aqueous solution is almost entirely absorbed (sorption rate>95%) at 25 ℃ with equilibrium sorption capacity of (11 747±539), (17 890±757) and (11 946±477) ng/g thalli (dry weight) for F3, F7 and F16 respectively within 30 min. Controlled by bulk diffusion and intraparticle diffusion process, the sorption process fits the pseudo-second-order kinetic model and Langmuir isotherm. Plutonium in the fungi can be quantificationally desorbed by 0.5 mol/L NaHCO3. More than 99% of plutonium is reclaimed by these fungi used for treatment of the high salinity radioactive waste liquid from a radiochemical laboratory.