离子交换与吸附

研究了红螺菌对Cu²⁺、Cr⁶⁺的吸附行为。结果表明,在pH2.9,35℃微光厌氧条件下,菌体对40mg/L Cu2+、Cr⁶⁺最大吸附率分别为94%、83.2%。利用红外光谱、原子力成像等方法,对吸附Cu²⁺、Cr⁶⁺前后的红螺菌进行了研究。红外光谱表明,羟基峰位红移,吸附Cu²⁺后峰位移动为22cm-1,吸附Cr⁶⁺后移动28cm-1,其它峰没有漂移,并且峰形基本保持不变,说明吸附后菌体的主要成分及结构保持完整。原子力成像表明,吸附前胞外聚合物分散分布,吸附后胞外聚合物出现交联,形成一个新的二维网状结构,并且吸附Cu²⁺后的交联程度比吸附Cr⁶⁺高。

The biosorption of Cu2+、Cr6+ by Rhodospirillum were investigated. The results indicated that the adsorption rate of Cu2+、Cr6+ by the strain were 94%、83.2%, respectively, when the adsorption process was carried out under anaerobic conditions with the pH of water 2.9, the temperature 35℃, and the faint illumination strength. Infrared spectroscopy and atomic force microscopy techniques have been used to study the changes before and after biosorption of heavy metals by Rhodospirillum. The IR spectrograms indicated that the apex of hydroxyl group (–OH) had a Einstein shift of 22cm-1 after adsorption of Cu2+, and that of Cr6+ was 28cm-1, the others did not shift and the shapes of apices did not change in essence. All of these indicated that the main components and structure of strain remained integral. The FAM demonstrated that the extracellular biopolymer of Rhodospirillum was dispersive before adsorption, but conglutination appeared after adsorption of heavy metals and formed a new double dimensional reticulation structure. At the same time the greater degree of conglutination was observed for sorption of copper than chromium.