不同生长阶段氧化亚铁硫杆菌的Cu^(2+)吸附研究

An experimental study of Cu^(2+) adsorption on Acidothiobacillus ferrooxidans of different growth stages

通过不同生长阶段的氧化亚铁硫杆菌对Cu2+的吸附实验研究,发现对数期和稳定期的氧化亚铁硫杆菌的Cu2+吸附容量存在一定差别,对数生长期比稳定期的氧化亚铁硫杆菌吸附量略高。同时,Cu2+的吸附量与溶液的pH值之间存在显著的负相关关系,说明在吸附过程中,Cu2+与氧化亚铁硫杆菌的表面存在的化学基团发生了质子交换反应。对数生长期的氧化亚铁硫杆菌和稳定期的氧化亚铁硫杆菌吸附过程均符合Freundlich吸附模型,表明氧化亚铁硫杆菌细胞的表面化学非均质性较强。不同生长阶段细菌的吸附性能差异可能与细胞表面的化学结构存在差异有关。

The adsorption of heavy metals on bacteria is often employed in the remediation of various contaminations. Nevertheless,the difference in the adsorption behaviors of the bacteria of different growth stages has not yet been systematically studied. Based on the adsorption experiments of Cu2＋ on Acidothiobacillus ferrooxidans at different growth stages,it is found that the adsorption capacity of the bacteria at the logarithmic stage is slightly higher than that of the stationary stage. The adsorption on the bacteria at the logarithmic stage and at the stationary stage can be described by Freundlich equations,implying its high surface heterogeneity. In addition,a negative correlation between the adsorption amount of bacteria and the pH of solution can be observed. Therefore,the displacement reaction between Cu2＋ and surface proton of the bacteria may constitute the adsorption mechanism. The changes in surface chemistry of the bacteria at different growth stages are considered to be responsible for the difference in adsorption behaviors.