真菌曲霉F77对水中Cs^+的吸附

Biosorption of Cesium Ions in Aqueous Solution by Aspergillus F77

微生物在环境放射性污染修复中具有广泛的应用前景。从放射性污染土壤中筛选出一株耐辐射真菌曲霉F77,研究了它对水中Cs+的吸附及其影响因素。结果表明:酸对Cs+在曲霉F77上的吸附存在竞争作用,pH=2.0~3.5溶液中的Cs+几乎不被曲霉F77吸附;曲霉F77生长过程中代谢产生大量的酸性物质;Cs+的吸附随着曲霉F77培养时间的增长而增大,在曲霉F77逐渐衰亡时吸附降低;K+质量浓度小于500mg/L时对Cs+在曲霉F77上的吸附没有影响,当K+质量浓度大于500mg/L时Cs+的吸附随K+浓度增大而减少;溶液中Cs+质量浓度为0~500mg/L范围内,曲霉F77对Cs+均有较高的吸附,Cs+质量浓度为500mg/L时,Cs+的吸附量为27.6mg/g。温度影响曲霉F77对Cs+吸附的快慢,不影响最后的吸附量;曲霉F77对Cs+具有较好的吸附性能,表明曲霉F77具有吸附剂的潜质。

Microorganisms, ever applied to remediation of heavy metal polluted soils, seems to be a prospective approach in radioactive contamination remediation. In our work, Asper- gillus F77 was separated from high-level radioactivity soils and used to remove Cs＋ from aqueous solutions. Effects of pH values, initial concentration of Cs＋ , concentration of kali- um on the biosorption of Cs＋ by Aspergillus F77, as well as the kinetics and thermodynamics, were investigated through batch progress. The results indicate that acids, including organic acids generated in the metabolism of Aspergillus F77, inhibite the growth of the aspergillus intensively. The effective biosorption of Cs＋ was found to be in the pH range of 2.0-3.5, probably because of the decrease of competition adsorption of H＋. When the concentration of Cs＋ is 500 mg/L, the amount of Cs＋ sorpted by Aspergillus F77 attains the maximum value of 27.6 mg/L. The present of kalium has no significant effect on the biosorption of Cs＋ when the concentration of kalium falls in the range of 0-500 mg/L, however, inhibits it evidently when kalium ions exceeds 500 mg/L, which is attributed to the competitive adsorp- tion of the homologous kalium. Kinetics studies show that the biosorption equilibration is achieved within 70 h. Due to its high biosorption ability to remove Cs＋ from aqueous solu- tions, Aspergillus F77 can be a potential biosorbent in biological remediation of Cs＋ contami- nated waters.