研究了粘红酵母对水溶液中铀的吸附行为,发现其吸附铀的最佳pH值为6~7,最大吸附量为149.4mgU·g^-1,其吸附等温线和Langmuir吸附等温方程符合较好,相关系数R2达到0.99;比较吸附铀前后粘红酵母的红外光谱图发现,吸附过铀的菌体的红外光谱在904cm^-1处出现了一个新的峰,此峰为UO2的伸缩振动峰,说明粘红酵母确实对铀发生了吸附作用。此外,氨基或羟基的伸缩振动峰由3309移至3287cm^-1,细胞壁中碳水化合物或醇中C—O键伸缩振动发生位移,由1068移至1080cm^-1,说明这些基团可能参与了吸附过程;蛋白质的特征吸收峰(1653,1540,1237cm^-1)在吸附前后基本无明显变化,表明粘红酵母的主要成分及结构仍保持完整。吸附后的菌体利用0.1mol·L^-1的NaHCO3处理后可解吸出其中96%的铀,可见该菌在铀矿废水处理方面具有广阔的应用前景。
Characteristic of uranium biosorption in water solution by Rhodotorula glutinis was investigated in the present study and the optimal pH for uranium adsorption was found to be 6-7. At the same time, maximum adsorption capacity of 149.4 mgU/ (g dry cell)was identified, and Langmuir adsorption models can be used to simulate the isothermal biosorption process with high eorrelation coefficient of 0. 99. According to Fourier transform infrared spectra, a new peak at wave number of 904 cm ^-1,which ean be assigned to the streteh vibration of UO2, was deteeted in the cell which was contacted by the uranium, indicated that uranium was really absorbed by Rhodotorula glutinis. Changes in the uranium-exposed yeast biomass were in the stretching vibrations of amino or hydroxyl groups, which shift from 3 309 to 3 287 cm^1, and in the stretching vibrations of C-O band, which shift from 1 068 to 1080 cm^-1 , and these are all attributed to the important role that they may played in the binding of uranium. Hardly any ehanges can be found in the characteristic IR adsorbing peaks of protein at wave numbers of 1 653, 1 540 and 1 237 cm^-1 before and after uranium adsorption, making it clear that the major component and the structure of the biomass remained intact. 96% of the absorbed uranium can be easily desorbed by 0. 1 mol · L^-1 NaHCO3. Obviously, the application potential of this yeast in the uranium wastewater treatment was very wide and expansive, and more more work should be done to realize its industrial use.