| Groundwater often existed in the rocks of the earth’s crust in various forms. Although it was not such a large pollution area as life or industrial wastewater, excessive concentration of iron, manganese and other metal ion were the common phenomenon. Excess manganese could impact industrial production and people’s daily life, even threaten human security. Therefore, it was necessary to removal the overdosage manganese in the groundwater. Over the years, national experts and scholars studied around the Mn2+biological adsorption, characteristics and mechanism of oxidation. However, due to the complexity of the structure of the biosorbent material, unpredictability of Mn2+oxidation process and oxidation products, Mn2+removal mechanism was still one of the difficult points of demanganization.A bacterium strain named Pseudomonas sp.4-05which had efficient removal ability of iron and manganese had been screened and identified from the Zijinshan copper well in our previous works.On this basis, this study researched on biosorption and bio-oxidation mechanism of manganese by the Pseudomonas sp.4-05. Detection the removal activity of manganese and functional positioning of the different parts had been done for the depth speculations and analysis of the mechanism of demanganization. Pseudomonas sp.4-05and agricultural waste wheat bran were mixed to be the compound micro-organic mate(?)us, and the preparation process was optimized and study its effect and manganese and manganese influence factors.We got the results as following:1. In this study, manganese activity tests of different parts with Pseudomonas sp.4-05fermentation broth were examined. Both thalli and fermentation supernatants had the ability on removal manganese, the removal rate of up to10.82%and95.82%respectively with the initial Mn+concentration of50μg/mL. Manganese removing was mainly due to pH. In addition, there were also other factors.2. The FTIR spectrum analysis of the thalli confirmed that the surface could be banded-OH,-CH2, N-H,-P=O groups, etc. The-OH and-P=O groups may be closely related with the adsorption of Mn2+,2nd order kinetics was found fit the test result well based on the correlation coefficient. The fitting coefficient was close to1, which indicated that the Mn2+biosorption of Pseudomonas sp.4-05was a fast chemisorption process.3. The siderophores was verified existed in the supernatant through different test methods. There were phenol-type siderophorea in the supernatant of Pseudomonas sp.4-05, but not catechol-type and hydroxamate siderophore. The phenol-type siderophore can be successful extractived by ethyl acetate and further purified by polyamide column chromatography. With the50ug/mL of manganese, the best conditions for manganese addition were the siderophore amount of10g/L, temperature of22℃,180r/min, the reaction of5min. The optimum medium for siderophore production was improved JFM Ⅱ medium. The optimal culture conditions were as follows, initial pH of8.5, temperature of28℃, incubation time of48h. The presence of iron ions in the environment would be completely suppressed the siderophore production with the concentration of10μM.4. The natural bran mixed with Pseudomonas sp.4-05with sodium carboxy methyl cellulose(CMC) as adhesive can be separated in the laboratory, and then introduced into the globular micro-organic compound material. Finally, the results of our experiments show that the best condition of preparation should be kept with the adhesive content being14%and the particle size being2.5cm. Under such conditions, it is possible to make the removing efficiency reach95.90%and62.35%for Fe2+(initial concentration=80mg/L) and Mn2+(initial concentration=2.5mg/L) respectively. |
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