Study on the mechanism of adsorption of lead ions biosorption by lactic acid bacteria

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.