本文選題：納米銀 + 微波合成法��； 參考：《華南理工大學(xué)》2014年碩士論文

【摘要】：生活飲用水安全與人體健康息息相關(guān)，而細(xì)菌超標(biāo)是造成生活飲用水不安全的首要原因。目前常規(guī)飲用水除菌殺菌技術(shù)都存在著各自的缺陷，因此，開發(fā)飲用水除菌殺菌的新方法、新材料，具有現(xiàn)實意義。 納米銀作為一種新型殺菌材料，具有高效、廣譜、安全等特性，在飲用水殺菌領(lǐng)域具有潛在應(yīng)用前景。研究發(fā)現(xiàn)納米銀的形貌對其性能有重要影響，然而納米銀形貌與其殺菌性能的關(guān)系尚未研究透徹。為此，本論文對納米銀的形貌可控合成、抗菌殺菌性能開展研究，以便為納米銀飲用水殺菌技術(shù)的應(yīng)用提供基礎(chǔ)依據(jù)，，研究得到以下主要結(jié)果和結(jié)論： 以20mL乙二醇為還原劑，90mg硝酸銀為銀源，運(yùn)用微波加熱合成法可快速制備銀納米結(jié)構(gòu)。投加氯離子控制合成體系的反應(yīng)速率，在適當(dāng)?shù)姆磻?yīng)時間內(nèi)，可選擇性合成出不同形貌納米銀。其中，在低NaCl投量水平下（小于0.1mg），獲得準(zhǔn)球形納米銀顆粒產(chǎn)物；在適中NaCl投量水平下（1mg），產(chǎn)物為以銀立方體為主的納米顆粒；在高NaCl投量水平下（5mg），獲得以銀納米線為主的產(chǎn)物。銀立方體的最優(yōu)合成條件為：氯化鈉投加量0.5-1mg，反應(yīng)時間2min；銀納米線的最優(yōu)合成條件為：氯化鈉投加量5mg，反應(yīng)時間3min30s。用電子顯微鏡、XRD、UV-Vis、SAED等手段對納米銀形貌、晶體結(jié)構(gòu)的表征結(jié)果為，球形納米銀直徑為60±15nm，為多晶結(jié)構(gòu)；銀立方體的邊長為55±10nm，為單晶結(jié)構(gòu)；銀納米線線徑60±10nm，線長2-4um，為孌晶結(jié)構(gòu)。 三種形態(tài)納米銀對大腸桿菌均具有抑菌和殺菌效果，抑菌殺菌效果隨納米銀濃度和反應(yīng)時間的延長而增強(qiáng)。銀立方體的殺菌效能最好，球形納米銀次之，銀納米線的殺菌作用最弱。銀立方體和球形納米銀對濃度為106CUF/mL的E. coli的最小殺菌濃度分別為75ug/mL和100ug/mL，而銀納米線濃度在0~100ug/mL范圍內(nèi)沒有MIC。當(dāng)納米銀的濃度為50ug/mL時，銀立方體可將E. coli的適應(yīng)期延長超過12h，球形納米銀能延長至9h，而銀納米線僅能延長6h。反應(yīng)1min，濃度25ug/mL的銀立方體和濃度100ug/mL的球形納米銀能完全滅活大腸桿菌，而銀納米線即使當(dāng)濃度達(dá)到100ug/mL時仍不能使細(xì)菌完全滅活。 納米銀殺菌性能既與其形貌相關(guān)，也與其晶面相關(guān)。與銀納米顆粒相比，銀納米線限于其一維納米結(jié)構(gòu)，長徑比大，與細(xì)菌的接觸相對不充分，導(dǎo)致其較弱的殺菌性能；銀立方體具有較高反應(yīng)活性的{100}晶面，殺菌效果較好，而球形納米銀暴露的{111}晶面相對穩(wěn)定，因而殺菌效果相對較差。 三種形態(tài)納米銀與細(xì)菌接觸過程中均能產(chǎn)生活性氧，并能氧化部分谷胱甘肽（GSH），活性氧誘發(fā)的氧化應(yīng)激是納米銀殺菌機(jī)制之一；半胱氨酸的加入能極大抑制納米銀的殺菌效能，銀離子的釋放也是納米銀殺菌機(jī)制之一，并且推測銀離子釋放量的不同是導(dǎo)致不同形態(tài)納米銀殺菌性能差異的主要原因。
[Abstract]:Drinking water safety is closely related to human health, and bacteria exceeding the standard is the primary cause of unsafe drinking water. At present, the common drinking water sterilization technology has its own defects. Therefore, it is of practical significance to develop new methods and materials for drinking water sterilization. As a new bactericidal material, silver nanoparticles have the characteristics of high efficiency, wide spectrum and safety, and have potential application prospect in the field of drinking water sterilization. It was found that the morphology of nano-silver had an important effect on its properties, but the relationship between the morphology of nano-silver and its bactericidal properties had not been thoroughly studied. Therefore, in this paper, the morphology of silver nanoparticles controllable synthesis, antibacterial and bactericidal properties of the study, in order to provide a basis for the application of nano-silver drinking water sterilization technology. The main results and conclusions are as follows: silver nanostructures can be prepared rapidly by microwave heating with 20 mL ethylene glycol as reducing agent 90 mg silver nitrate as silver source. The nano-silver with different morphologies can be selectively synthesized by adding chlorine ion to control the reaction rate of the synthesis system and under the appropriate reaction time. At low NaCl dosage (less than 0.1mg), quasi spherical silver nanoparticles were obtained; at moderate NaCl dosage level (1mg), silver cube was the main product; at high NaCl dosage level (5mg), silver nanowires were obtained. The optimum synthesis conditions of silver cube were as follows: dosage of sodium chloride 0.5-1 mg, reaction time 2 min, and the optimum synthesis conditions of silver nanowires were: dosage of sodium chloride 5 mg, reaction time 3 min 30 s. The morphology of silver nanocrystalline was characterized by XRD- UV-Vis-SAED. The results showed that the diameter of spherical nanocrystalline silver was 60 鹵15nm, the side length of silver cube was 55 鹵10nm, and the diameter of silver nanowire was 60 鹵10nm, the length of silver nanowire was 2-4um. The bacteriostatic and bactericidal effects of the three forms of silver nanoparticles on Escherichia coli were enhanced with the prolongation of the concentration and reaction time of silver nanoparticles. Silver cube has the best bactericidal efficacy, spherical silver is the second, silver nanowires have the weakest bactericidal effect. The minimum bactericidal concentration of silver cube and spherical silver nanocrystalline was 75ugr / mL and 100ugr / mL for E. coli with 106CUFP / mL, respectively, while the concentration of silver nanowires was not MICM in the range of 0 ~ 100ugr / mL. When the concentration of silver nanoparticles was 50ugr / mL, the adaptation period of E. coli was prolonged by silver cube for more than 12 hours, the spherical silver nanoparticles for 9 hours, and silver nanowires for only 6 hours. For 1 min, the silver cube of 25ug-mL and the spherical silver of 100ug-mL could completely inactivate Escherichia coli, but the silver nanowires could not completely inactivate the bacteria even when the concentration reached 100ugr / mL. The bactericidal properties of silver nanoparticles are not only related to their morphology, but also to their crystal planes. Compared with silver nanoparticles, silver nanowires are confined to their one-dimensional nanostructures, with large aspect ratio and relatively inadequate contact with bacteria, which leads to their weaker bactericidal properties, and the {100} crystal plane with higher reactivity of silver cube has better bactericidal effect. The {111} crystal plane exposed to spherical silver is relatively stable, so the bactericidal effect is relatively poor. Reactive oxygen species (Ros) and partial glutathione (GSH) can be oxidized during contact with bacteria. Oxidative stress induced by Ros is one of the bactericidal mechanisms of nano-silver, and cysteine can greatly inhibit the bactericidal efficacy of nanocrystalline silver. The release of silver ions is also one of the bactericidal mechanisms of nano-silver, and it is speculated that the difference in the amount of silver ions released is the main reason leading to the differences of bactericidal properties of nano-silver in different forms.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU991.2

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