脱硫脱硫弧菌生物合成纳米硫化铅的研究

发布时间：2018-03-28 20:48

  本文选题：脱硫脱硫弧菌　切入点：纳米硫化铅　出处：《中北大学》2015年硕士论文

【摘要】：纳米硫化铅独特的性能，使其在光学、磁学、电学和医学等领域拥有巨大开发潜力和应用价值。目前纳米硫化铅的制备方法仍是以物理化学方法为主，这些研究不论在方法、应用还是机理方面都已经取得了重大的进展，积累了丰富的成果。随着环境友好、绿色化学等思想的转变，人们趋向于寻找更为简单、绿色的合成方法。微生物法因具有成本低、反应过程简单、整个合成过程可用微生物进行自我调控、对环境更为友好等特点，发展前景广阔。 本实验采用脱硫脱硫弧菌生物合成纳米PbS，研究了合成过程中不同因素对产物结构、形貌、尺寸以及转化率的影响，并测定产物的光催化、紫外可见吸收和光致发光性能，最后对机理进行了初探，得到以下结论： （1）用脱硫脱硫弧菌成功地制备出纳米PbS，采用XRD、HRTEM和EDS对产物进行详细表征，并考察了制备过程中pH值、温度和接种量对产物形貌、结构、尺寸以及转化率的影响，结果表明：随着pH值由5增大至8，产物的形貌由近球形变为颗粒状，粒径由10~15nm增大至10~25nm，pH值为9时，制备出颗粒状周围镶嵌近球形颗粒这种特殊的不规则状纳米PbS，粒径为10~15nm，pH值为8时转化率最高；不同温度下制得的纳米PbS具有相同的结构、形貌和大小，颗粒状，粒径为10~25nm，30℃时转化率最高；随着接种量的增大，制备的纳米PbS由球形变为颗粒状，粒径由5~10nm增至10~25nm，，接种量为10%时转化率最高。 （2）用制备的纳米PbS光催化降解甲基橙和亚甲基蓝溶液，降解过程基本符合一级动力学。不同pH值下制备的纳米PbS光催化降解效果为pH9pH8pH7pH6pH5，不同温度下制备的纳米PbS光催化效果为30℃25℃15℃，不同接种量下制备的纳米PbS光催化效果为5%10%20%，pH为9时制得的纳米PbS光催化效果最佳，紫外光照射6h后，对甲基橙和亚甲基蓝溶液的降解率分别为77.37%和93.43%。 （3）以pH9制备的纳米PbS为催化剂，考察甲基橙和亚甲基蓝溶液初始pH值和催化剂投加量对降解率的影响，得出最佳降解条件：纳米PbS投加量1.5g/L，溶液初始pH值为3，紫外光照射4h时对20mg/L甲基橙降解率为99.04%；纳米PbS投加量1.8g/L，溶液初始pH值为10，紫外光照射4h时对8mg/L亚甲基蓝降解率为99.05%。 （4）纳米PbS的紫外可见吸收光谱和荧光光谱均表现出了明显的蓝移现象，说明制备的产品粒径小，发生了量子尺寸效应。 （5）APS还原酶和亚硫酸盐还原酶比活力测定结果表明，随着培养时间的增加，两种酶呈现先增大后减小的趋势，在83h时酶比活力同时达到最高峰。说明APS还原酶和亚硫酸盐还原酶是随着菌株培养时间同时变化的。对比不同pH值下酶比活力大小，pH为7时APS还原酶比活力最高，pH为8时亚硫酸盐还原酶比活力最高；对比不同温度下两种酶比活力，培养温度为30℃时，两种酶的比活力均达到最大值；对比不同接种量下酶比活力，接种量为10%时两种酶比活力最大。结合不同条件下铅转化率的测定结果，说明酶活性的大小对菌株的生理代谢影响很大，酶活性大，则对铅的转化率高。 （6）在含铅培养基中，菌株亚细胞各组分铅离子含量测定结果表明，细胞壁占13.95%，细胞膜占66.90%，细胞质占19.15%。由此推断，铅离子可能在细胞膜表面富集。菌株的高分辨透射电镜照片和能谱图表明，在脱硫脱硫弧菌制备纳米PbS的过程中，在菌体内部有纳米PbS生成。
[Abstract]:The unique properties of nano lead sulfide, the optics, magnetism, has a huge development potential and application value of electrical and medical fields. At present, the preparation methods of nano lead sulfide is by physical and chemical methods, these studies in methods, application or mechanism has made significant progress, accumulated rich results. With the change of environment friendly, green chemistry idea, people tend to find a more simple and green synthetic method. The microbial method has the advantages of low cost, simple reaction process, the synthesis process of available microbial self regulation, more environmentally friendly, broad prospects for development.
This experiment adopts d.desulfuricans biosynthesis of nano PbS, the morphology of different factors in the synthesis process of product structure, size effect and transformation rate, and determination of photocatalytic products, UV Vis absorption and photoluminescence properties, finally the mechanism of the study, obtained the following conclusions:
(1) for d.desulfuricans was successfully prepared by nano PbS, XRD, HRTEM and EDS for a detailed characterization of the product, and the effects of the preparation process of pH value, temperature and inoculation amount on the structure, morphology, size effect, and the results show that with the conversion rate increased from 5 to pH 8, the morphology of the products by nearly spherical into granular, particle size increased from 10~15nm to 10~25nm, the pH value is 9, preparation of granular inlay around nearly spherical particles of this special irregular shaped nano PbS, diameter of 10~15nm, when the pH value is 8 the highest conversion rate under different temperature were prepared; nano PbS has the same structure, morphology and size of particles, particle size is 10~25nm, 30 DEG C when the highest conversion rate; with the increase of inoculation, the preparation of nano PbS by spherical into granular, particle size increased from 5~10nm to 10~25nm, when the inoculation amount was 10%, the conversion rate is high.
(2) used in the preparation of nano PbS photocatalytic degradation of methyl orange and methylene blue solution, the degradation process accords with the first-order kinetics. The effect of different pH value of nano PbS photocatalytic degradation under preparation for pH9pH8pH7pH6pH5 at different temperatures for nano PbS photocatalytic effect for the preparation of 30 C 25 C 15 C, different inoculation preparation of nano PbS photocatalytic effect for the preparation of 5%10%20% pH nano PbS photocatalytic effect of 9 was the best, 6h UV irradiation, the degradation of methyl orange and methylene blue solution were respectively 77.37% and 93.43%.
(3) the preparation of pH9 nano PbS as catalyst, effects of methylene blue and methyl orange solution initial pH and catalyst dosage on the degradation rate were investigated, the optimum degradation conditions: nano PbS dosage of 1.5g/L, initial pH value 3, 4H UV irradiation of 20mg/L methyl orange degradation rate was 99.04%; nano PbS dosage of 1.8g/L, initial pH value 10, 4H UV irradiation on the degradation rate of methylene blue is 99.05%. 8mg/L
(4) the UV Vis absorption and fluorescence spectra of nano PbS showed obvious blue shift, which indicated that the size of products was small, and the quantum size effect occurred.
(5) APS reductase and sulfite reductase activity were tested. The results show that with the increase of culture time, two kinds of enzymes was first increased and then decreased, when 83h enzyme specific activity reached a peak at the same time. The results showed that APS reductase and sulfite reductase with incubation time and strain change. Compared with different pH values than enzyme activity pH is 7 APS, the highest specific activity of pH reductase, 8 sulfite reductase activity is highest; two under different temperature enzyme specific activity, culture temperature is 30 degrees centigrade, the ratio of the two enzyme activity reached the maximum value; comparison of different inoculation ratio of enzyme activity, the inoculation amount was 10% two kinds of enzyme activity. The determination results under different conditions of lead conversion, shows great influence on the size of the physiological activity of metabolic enzyme strains, enzyme activity, is transformed to lead high rate.
(6) the lead in medium strain subcellular fractions of lead ion content determination results showed that cell wall accounted for 13.95%, accounted for 66.90% of the cell membrane, cytoplasm 19.15%. inferred that the lead ion may surface enrichment in the cell membrane. The strain of high resolution transmission electron microscope photograph and energy spectrum shows that in the process of d.desulfuricans system the preparation of nano PbS, nano PbS generated in the cell interior.

【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ134.33

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