Biosorption Of Cesium Ions In Aqueous Solution By Aspergillus F77

The contamination of wastewaters by radionuclide is a difficult environmental problem. Microorganisms have widely application prospects in the radioactive contamination remediation. The effects of the biosorption of cesium ions by selected and acclimated microorganism were investigated using a batch method in varieties detail. The results were showed:A radiation-tolerant Aspergillus F77strain, separated from the radioactivity soils, was used to remove cesium ions from aqueous solutions as a biosorbent, and the effects of Aspergillus F77strain biosorption were also studied, under the radiant dose of2.0kGy-20kGy, Aspergillus F77wes no distinct the effects under experimental radiation condition. The toleranee of Aspergillus F77strain to salt enhaner, and reached23g/L. The Aspergillus F77strain had high resistance to heavy metals, even under lead concentration of1000mg/L.It is important to study the sorption behaviors of cesium onto Aspergillus F77strain.The following results and conclusions were obtained:A lot of organic acids were metabolized in Aspergillus F77strain growth procedure. The growth of Aspergillus F77strain was restrained by acid evidently, the biosorption of cesium ions by Aspergillus F77occurred hardly in the pH range of2.0, but the biosorption ratio of cesium was upto70%above7>pH>4.5. The growed speed of Aspergillus F77strain was affected by the temperature. When the temperature was30℃, PDA was100ml, the adsorption time was70h. When oxygen was supply and the rotation speed was120-160rpm, and Aspergillus F77had good effect to cesium ions in the solution. When oxygen was not supply, Aspergillus F77metabolized more and more organic acids in growth procedure. The results were showed it was not affected that how much were inoculation volune and PDA volune on the mieroorganisms adsorbed cesium, but PDA volune was addition, and Aspergillus F77was growth more thallus strain. When cesium concentration had500mg/L, that the biosorption ratio of cesium was60%and the adsorption capacity of cesium reached30mg/g. The sorption of cesium decreased with potassium ionic and calcium ionic increasing, and the competing ability of cations followed an order Ca2+>K+. The capacity of living cells is significantly higher than that of noliving cells, and the ratio of cesium on noliving was only10%. Aspergillus F77strain has good biosorption ability to remove cesium ions from aqueous solution, and it can be applied in biological remediation of the polluted water and soil.