德氏乳杆菌吸附铅离子的机制研究
Study on the mechanism of adsorption of lead ions biosorption by lactic acid bacteria
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摘要: 该研究以具有较高去除铅离子能力的德氏乳杆菌(Lactobacillus delbrueckii)KLDS1.0207为研究对象,利用热力学模型及动力学模型对Lactobacillus delbrueckii KLDS1.0207结合铅离子的过程进行模拟分析,同时结合扫描电镜-能谱及傅里叶红外光谱对其结合铅离子的状态进行分析,最后得出,Langmuir-Freundlich模型比Langmuir模型和Freundlich模型更适合其结合铅离子的过程,R2达0.9820,准二级动力学模型的R2为0.9916,比准一级动力学模型更适合,说明该菌与铅的作用的机制为化学吸附,而不是物理吸附。由扫描电镜和能谱分析可以看出菌体表面不完全分布着铅的颗粒,推断出参与吸附过程中其主要作用的是含C、O的基团和傅里叶红外光谱,可以推测出参与铅离子结合的基团有羧基、氨基、酰胺基、羟基,推测菌与铅的作用机制可能为化学吸附、离子交换、化学沉淀等的共同作用的结果。Abstract: Using the lactic acid bacteria KLDS1.0207 with good sequestering Pb2 +as the research object,the thermodynamic model and kinetic model were served to analysis the process of lactic acid bacteria KLDS1.0207 binding lead ion,at the same time combined with scanning electron microscopy- energy spectrum and Fourier infrared spectrum analysis of the combination of lead ion state. Finally the result concluded that the adsorption equilibrium data fitting showed the Langmuir Freundlich model( R~2= 0.9820) was more suitable for the process of the combination of lead ions aganist the Langmuir model and Freundlich model.Pseudo second order model( R~2=0.9916) had dominance in comparison to pseudo first order,indicating that the mechanism of action of the bacteria and lead to chemical adsorption,rather than physical adsorption.By the SEM and EDS analysis could be seen in the cell surface was not completely distributed lead particles,inferred involved in the adsorption process and its main role was to contain C,O group. Through the SEM- EDS and FTIR spectra,could be inferred the function groups like carboxyl,amino,amide,hydroxyl were taken part in the process of lactic acid bacteria binding the lead ions.The mechanism might include chemical adsorption,ion exchange,chemical precipitation,etc.