【作者】 刘晓燕；

【导师】 王向东；

【作者基本信息】 四川大学 ， 环境工程， 2005， 硕士

【摘要】 铁、锰氧化细菌与软锰矿共同作用脱除烟气中的SO₂是一种新的脱硫方法。铁、锰氧化细菌一方面可以将软锰矿脱硫过程中被还原的低价铁、锰离子氧化成Fe³⁺和Mn⁴⁺,恢复其催化氧化能力,实现软锰矿脱硫过程的循环进行,另一方面又可以直接氧化烟气中的SO₂,提高脱硫效果。而铁、锰氧化细菌对Fe²⁺、Mn²⁺的氧化效果受环境的影响很大,菌种活性太低限制了其在脱硫中的应用;同时它们有各自独特的生理特性,要将其应用于脱硫体系中,必须使二者都能适应脱硫体系的酸性环境。因此,选育繁殖速度快、活性强、对pH有更广泛适应性的铁锰氧化细菌菌株是提高其对Fe²⁺、Mn²⁺、SO₃^2-氧化能力,进而提高软锰矿与微生物联合脱硫效率的关键。 本研究关于铁、锰氧化细菌高效菌株的选育是软锰矿与细菌共同催化氧化烟气中二氧化硫课题的前期研究工作。在实验过程中,采用紫外线诱变育种方法筛选出适应pH范围宽、Fe²⁺、Mn²⁺离子转化效率高的菌株;研究了铁、锰氧化细菌对Fe²⁺、Mn²⁺及SO₃^2-的氧化规律,确定其动力学参数。同时考察了在Fe²⁺、Mn²⁺转化过程中的溶解氧变化规律。 研究结果表明:经紫外线诱变选育出了高效氧化亚铁硫杆菌LT5.0菌株。该菌株在温度为30℃、摇床转速为150r/min、Fe²⁺浓度为6.5g/L、pH为2.5、4.0、5.0条件下,对Fe²⁺转化率在24～30小时内达到100%;当pH为2.5、Fe²⁺浓度为3.5g/L～15.5g几时,对Fe²⁺的氧化反应近似为一级反应,其速率常数为0.0468～0.0615h^-1。氧化亚铁硫杆菌诱变菌株对SO₃^2-离子的转化速率明显优于化学氧化,当SO₃^2-浓度为2.8g/L时,LT5.0菌株对SO₃^2-离子的氧化速率更多还原

【Abstract】 Combination of pyrolusite and ferromanganese-oxidation bacteria to desulphurize flue gas is a new method. In the system, ferromanganese-oxidation bacteria are applied to oxidize and regenerate Fe~2+ and Mn~2+ in order to renew the catalyzers, MnO2 and Fe2O3, and maintain the desulphurization ability of the pyrolusite. At the same time, Thiobaciiius ferrooxidans can directly oxidize SO2, which further improve desulphurization efficiency of the whole system. But the oxidation efficiency of Mn~2+ and Fe~2+ by ferromanganese-oxidation bacteria greatly depends on the bacterial survival environment and the low activity limited their application to the practical desulphurization process. Hence, selecting ferromanganese-oxidation bacteria which has high oxidation efficiency to Mn2+ and Fe2+ and can live in a wider pH range is the key point to the desulphurization efficiency of the combination system of pyrolusite and ferromanganese-oxidation bacteria.In this paper, mutagenic selection of ferromanganese-oxidation bacteria by ultraviolet radiation was carried out in order to obtain bacteria of high efficiency. Oxidation process of Fe2+, Mn2+ and SO32" by ferromanganese-oxidation bacteria was studied and the kinetics parameter was obtained. Meanwhile, changes of dissolved oxygen during the oxidation process were investigated.After mutagenic selection of ferromanganese-oxidation bacteria by ultraviolet radiation, those of high efficiency, LT 5.0 and ML1 were obtained. The study results indicated that at 30°C, agitation rate 150 r/min, concentration of Fe2+ 6.5 mg/L, initial pH=2.5^ 4. 5, Fe2+ will be totally oxidized in 24h> 24h, 30h respectively. At pH=2.5. Fe2+ concentration ranging from 3.5g/L to 15.5g/L, oxidation of Fe2+ by Thiobaciiius ferrooxidans followed first-order kinetics with the velocity constant equal to 0.0468~0.0615h"’. In the absence of Fe2+, oxidation rate of SO32 by Thiobaciiius ferrooxidans is better than that of without bacteria. In the presence of Fe2+, direct oxidation to SO32" by the bacteria is not obvious. At 30°C, agitation rate 120 r/min, concentration of Mn2+ 140 mg/L, initial pH=^ 5, 6, 7, 57.36% ^ 65.58 %, 68.78 % ? 74.45 % of Mn2+can be oxidized respectively by LM1. At pH=4, Mn2+ concentration ranging from 70mg/L to 500mg/L, oxidation of Mn2+ by manganese-oxidation bacteria followed first-order kinetics with the velocity constant equal to 0.012~0.0275h~!. At pH=6 and Mn2+concentration ranging from 60mg/L to 290mg/L, oxidation of Mn2+ also followed first-order kinetics with the velocity constant equal to 0.006~0.0145h~1.These study results can offer important basic data for research of combination desulphurization system of pyrolusite and ferromanganese-oxidation bacteria. And valuable references will be provided for further study on fundamental theory of microorganism to be used in desulphurization.更多还原