光催化纳米颗粒强化光发酵细菌Rhodopseudomonas sp.nov.strain A7产氢规律与机制研究

发布时间：2018-05-12 04:08

  本文选题：光催化 + 纳米颗粒　； 参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：目前,能源短缺仍是当今世界面临的重要问题,研究光发酵法生物制氢技术对新能源的开发利用具有重要的现实意义。然而,光发酵法生物制氢技术面临一些关键性技术瓶颈问题需要克服,如产氢效率、底物利用效率和光能转化率较低等。光催化纳米颗粒可利用光能进行光催化产氢,在材料领域中被较多使用。本课题将光催化和光发酵结合,以期提高光发酵产氢效率、改善底物利用率和光能转化效率。本文研究了三种具有光催化性能的纳米颗粒Ti O2、Zn O和Si C对光发酵细菌Rhodopseudomonas sp.nov.strain A7产氢的影响规律,优选出最佳的促进产氢的纳米颗粒,通过改性进一步提高其光催化能力及对光发酵细菌的底物转化能力;并研究了三个关键因素即光源、光照强度和光催化纳米颗粒浓度对光发酵产氢体系的影响规律;多尺度分析探讨了光催化纳米颗粒强化光发酵产氢的机理。纳米颗粒Ti O2、Zn O和Si C在一定条件下均能不同程度地提高菌株A7的产氢能力。其中Si C在最佳浓度为200mg/L、制备温度为1500℃时,能使光发酵细菌菌株A7获得最大的氢气产量、平均氢气含量和比产氢率,分别达到2272m L-H2/L-培养基、85.2%和2.99 mol-H2/mol-乙酸,氢气产量同对照相比提高18.6%。为了进一步提高光催化纳米颗粒对光发酵产氢的强化效果,采用表面改性和半导体复合改性两种方法对Si C进行改性处理,得到Si C/PAA和Si C/Fe3O4纳米颗粒。结果表明:二者能够进一步提高菌株A7的产氢性能,最佳纳米颗粒浓度分别为200和100mg/L,Si C/Fe3O4纳米颗粒的光催化效率较高,整体性能优于Si C和Si C/PAA纳米颗粒。当Si C/Fe3O4纳米颗粒存在于体系中时,光发酵菌株A7获得最大的氢气产量、平均氢气含量、比产氢率和光能转化效率,分别为2474 m L-H2/L-培养基、88.9%、3.02 mol-H2/mol-乙酸和0.45%,同对照相比,氢气产量、生物量和光能转化效率分别提高34.4%、26%和36.4%。当采用氙灯为光源,普通玻璃厌氧瓶为反应器,最佳光照强度为100W/m2,Si C、Si C/PAA和Si C/Fe3O4的最佳浓度分别为150、150和100mg/L时,菌株A7的各项产氢指标和光能转化效率均得到了明显提高,其中Si C/Fe3O4对菌株A7的影响最为有利,氢气产量、平均氢气含量、比产氢率和光能转化效率分别达到2464m L-H2/L-培养基、93.6%、3.16 mol-H2/mol-乙酸和1.06%,同对照相比,氢气产量和光能转化效率分别提高达34.2%和32.5%。本论文研究结果表明:光催化纳米颗粒实现了对光发酵的产氢强化作用,即能够通过提高菌株A7的凝集性能,改变细菌表面元素、官能团的种类和含量、提高固氮酶的活性、降低吸氢酶的活性、促进和加速产氢体系的电子转移速率,进而提高体系的比产氢率和氢气含量,提高底物利用率和光能转化效率。
[Abstract]:At present, energy shortage is still an important problem facing the world. It is of great practical significance to study the biological hydrogen production technology of light fermenting method for the development and utilization of new energy. However, the biological hydrogen production by light fermentation is facing some key technical bottlenecks, such as hydrogen production efficiency, substrate utilization efficiency and light energy conversion rate. Photocatalytic nanoparticles are widely used in the field of materials for photocatalytic hydrogen production. In order to improve the efficiency of hydrogen production, the utilization rate of substrate and the conversion efficiency of light energy were improved by combining photocatalysis with photofermentation. In this paper, the effects of three photocatalytic nanoparticles, TIO _ 2, Zn-O and sic, on the hydrogen production of Rhodopseudomonas sp.nov.strain A _ 7 by photofermentation were studied, and the best nanocrystalline particles for hydrogen production were selected. The effects of three key factors, namely light source, light intensity and the concentration of photocatalytic nanoparticles, on the photo-fermenting hydrogen production system were studied. The mechanism of photocatalytic nanocrystalline enhanced photofermentation for hydrogen production was discussed by multi-scale analysis. The hydrogen production ability of strain A7 can be improved by nano-particles TIO _ 2 Zn-O and sic under certain conditions. When the optimum concentration of sic was 200 mg / L and the preparation temperature was 1500 鈩，

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