Coercive effects of different exogenous Cd(Ⅱ)on Pseudomonas aeruginosa EPS——Changes in yield,composition,adsorption characteristics and their mechanisms
The effects of anions on the yield and characteristics of Pseudomonas aeruginosa EPS and its performance on Cd(Ⅱ)adsorption were compared by using CdCl2,CdSO4 and Cd(NO3)2 as stress factors.The results showed that the maximum EPS yield of 214.91mg/g VSS(136.75mg/g VSS in protein content)was observed for Cd(NO3)2 at a concentration of 50mg/L,which was 409.31％higher than that before stress/induction.Under this condition,the maximum adsorption capacity for Cd(Ⅱ)by the EPS was achieved,which was 50％higher than that before stress/induction.HPLC analysis showed that the changes of amino acids in EPS proteins were closely related to the adsorption characteristics of EPS.The results of 3D-EEM,XPS and FTIR showed that the content of C=O,C-N and N-H in EPS increased,which was conducive to the binding of heavy metals.Through competitive adsorption experiments,it was found that EPS has a higher affinity for Cd(Ⅱ)than Zn(Ⅱ).
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