Sorption characteristics of Pb(II) from aqueous solution by extracellular polymeric substance (EPS-07) of lead-resistant and producing flocculant strain Klebsiella pneumonia

The biosorption characteristics of extracellular polymeric substance (EPS-07) of producing flocculant strain B-07 as lead-resistant for the removal of Pb(II) from aqueous solution were studied. The results show that the extent of adsorption capacity is 61.5 mg/g when the dosage of EPS-07 is 0.8 g/L, pH=5.5, adsorption contact time is 80 min, initial Pb(II) concentration of aqueous solution is 50 mg/L, respectively. The biosorption equilibrium data are better described by Langmuir isotherm model, and the adsorption reaction of Pb(II) by EPS-07 follows the second-order kinetic model. The carboxy, hydroxyl groups of EPS-07 are involved in chemical interaction with the Pb(II) ions depicted by Fourier transform infrared spectroscopic (FT-IR) results. Moreover, SEM observation indicates that the EPS-07 surface is loose, and then obviously changes to campact after the EPS-07 surface loaded with with Pb(II), where cry stalline deposits are deposited on the EPS-07 surface. Also, biosorption of Pb(II) is confirmed by EDS analysis, which reveales the presence of Pb(II) signals on the EPS-07 surface.