| In this paper,the biosorption of copper.chromium in the waste water was studied comprehensively by using phytosysthetic bacteria. The research covers selection of biosorbents,capability of sorption,kinetics analysis,desorption and reuse,mechanism of biosorption and biosorbent cheap culture.Biosorption of copper ion by phytosysthetic bacteria was studied in the first place. Four strains of phytosysthetic bacteria were used as biosorbents to deal with Cu2+ in wastewater. It was shown that Rhodospirillum R-OI,R-02,R-04 had high biosorption capacities for copper ion, among which R-04 had the most excellent ability to adsorb copper and its removal rate could reach 99.1%, when the concentration of copper was 20mg/l. The optimal uptake conditions for R-04 were: pH=2,Cu2+80mg/l, 35 C,weak light and anaerobic for 45min.Under these conditions, the removal rate and the biosorption capacity could reach 94%,48.03mg/g,respectively. The bacteria could grow in many kinds of carbon and nitrogen sources, but the adsorption efficiency was different with different culture conditions.The kinetics analysis of copper onto the Rhodospirillum R-04 was investigated. The experimental results showed that the biosorption process followed the pseudo-second-order kinetics model. The sorption process of copper in determinated concentration was in accordance with both Langmuir and Freundlich isotherm, but better complied with Langmuir model.It was found that EDTA and citric acid were the effective eluants for the elution of adsorbed copper by R-04, the elution efficiency wrere 86.4%, 66.9%,respectively. Regeneration of R-04 was not satisfactory, although adsorbing performance did not decrease obviously after reusing twice. Adsorbing performance dropped greatly when it was reused third times.Infrared spectroscopy and atomic force microscopy techniques have been used to study the changes before and after biosorption of heavy metals by R-04. The IR spectrograms indicated that the apex of hydroxyl group(-OH) had a Einstein shift of 22cm-1 after adsorption of Cu2+,and that of Cr6+ was 28cm-1, the others did not shiftand the shapes of apices did not change in essence. All of these indicated that the main components and structure of strain remained integral. The FAM demonstrated that the extracellular biopolymer of R-04 was dispersive before adsorption, but conglutination appeared after adsorption of heavy metals and formed a new double dimensional reticulation structure. At the same time the greater degree of conglutination was observed for sorption of copper than chromium. The analysis of the X-ray diffraction spectra indicated that the bacteria did not form new crystal after the adsorption and some of the crystal of the bacteria had transformed into non-crystal.The research on the cheap substitute of biosorbent culture found that R-04 could grow normally in beer producing waste water and the strain cultured by this way had the same ability to adsorp copper with that which had been obtained in laboratory culture.
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