本文選題：脫硫脫硫弧菌　切入點：納米硫化鉛　出處：《中北大學》2015年碩士論文

【摘要】：納米硫化鉛獨特的性能，使其在光學、磁學、電學和醫(yī)學等領域擁有巨大開發(fā)潛力和應用價值。目前納米硫化鉛的制備方法仍是以物理化學方法為主，這些研究不論在方法、應用還是機理方面都已經取得了重大的進展，積累了豐富的成果。隨著環(huán)境友好、綠色化學等思想的轉變，人們趨向于尋找更為簡單、綠色的合成方法。微生物法因具有成本低、反應過程簡單、整個合成過程可用微生物進行自我調控、對環(huán)境更為友好等特點，發(fā)展前景廣闊。 本實驗采用脫硫脫硫弧菌生物合成納米PbS，研究了合成過程中不同因素對產物結構、形貌、尺寸以及轉化率的影響，并測定產物的光催化、紫外可見吸收和光致發(fā)光性能，最后對機理進行了初探，得到以下結論： （1）用脫硫脫硫弧菌成功地制備出納米PbS，采用XRD、HRTEM和EDS對產物進行詳細表征，并考察了制備過程中pH值、溫度和接種量對產物形貌、結構、尺寸以及轉化率的影響，結果表明：隨著pH值由5增大至8，產物的形貌由近球形變?yōu)轭w粒狀，粒徑由10~15nm增大至10~25nm，pH值為9時，制備出顆粒狀周圍鑲嵌近球形顆粒這種特殊的不規(guī)則狀納米PbS，粒徑為10~15nm，pH值為8時轉化率最高；不同溫度下制得的納米PbS具有相同的結構、形貌和大小，顆粒狀，粒徑為10~25nm，30℃時轉化率最高；隨著接種量的增大，制備的納米PbS由球形變?yōu)轭w粒狀，粒徑由5~10nm增至10~25nm，，接種量為10%時轉化率最高。 （2）用制備的納米PbS光催化降解甲基橙和亞甲基藍溶液，降解過程基本符合一級動力學。不同pH值下制備的納米PbS光催化降解效果為pH9pH8pH7pH6pH5，不同溫度下制備的納米PbS光催化效果為30℃25℃15℃，不同接種量下制備的納米PbS光催化效果為5%10%20%，pH為9時制得的納米PbS光催化效果最佳，紫外光照射6h后，對甲基橙和亞甲基藍溶液的降解率分別為77.37%和93.43%。 （3）以pH9制備的納米PbS為催化劑，考察甲基橙和亞甲基藍溶液初始pH值和催化劑投加量對降解率的影響，得出最佳降解條件：納米PbS投加量1.5g/L，溶液初始pH值為3，紫外光照射4h時對20mg/L甲基橙降解率為99.04%；納米PbS投加量1.8g/L，溶液初始pH值為10，紫外光照射4h時對8mg/L亞甲基藍降解率為99.05%。 （4）納米PbS的紫外可見吸收光譜和熒光光譜均表現出了明顯的藍移現象，說明制備的產品粒徑小，發(fā)生了量子尺寸效應。 （5）APS還原酶和亞硫酸鹽還原酶比活力測定結果表明，隨著培養(yǎng)時間的增加，兩種酶呈現先增大后減小的趨勢，在83h時酶比活力同時達到最高峰。說明APS還原酶和亞硫酸鹽還原酶是隨著菌株培養(yǎng)時間同時變化的。對比不同pH值下酶比活力大小，pH為7時APS還原酶比活力最高，pH為8時亞硫酸鹽還原酶比活力最高；對比不同溫度下兩種酶比活力，培養(yǎng)溫度為30℃時，兩種酶的比活力均達到最大值；對比不同接種量下酶比活力，接種量為10%時兩種酶比活力最大。結合不同條件下鉛轉化率的測定結果，說明酶活性的大小對菌株的生理代謝影響很大，酶活性大，則對鉛的轉化率高。 （6）在含鉛培養(yǎng)基中，菌株亞細胞各組分鉛離子含量測定結果表明，細胞壁占13.95%，細胞膜占66.90%，細胞質占19.15%。由此推斷，鉛離子可能在細胞膜表面富集。菌株的高分辨透射電鏡照片和能譜圖表明，在脫硫脫硫弧菌制備納米PbS的過程中，在菌體內部有納米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.

【學位授予單位】：中北大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ134.33

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