| 题名 | 纳米结构MgO粉体的制备与性能研究 |
| 作者 | 崔洪梅 |
| 学位类别 | 博士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 陈运法 |
| 关键词 | 氧化镁 掺杂 缺陷 抗菌性能 复合抗菌材料 |
| 其他题名 | Preparation and Antibacterial Property Investigation of Nano Magnesium Oxide |
| 学位专业 | 环境工程 |
| 中文摘要 | 氧化镁作为一种多功能的材料，在许多领域有着广阔应用前景，特别是在与人类健康相关的抗菌方面显示出独特的优势。由于氧化镁表面的缺陷、边、阶等活性位的存在使得氧化镁能吸附其它抗菌组分制备复合抗菌材料，确保具有广谱、高效且能迅速杀灭、抑制细菌、芽孢、病毒的性能。本文通过在MgO体系中引入不同价态金属离子，制备了尺寸小、比表面积大且吸附性能好的纳米MgO，通过简便工艺制备了几种不同类型的多孔MgO。考察了MgO微观结构以及元素掺杂对其吸附性能和抗菌性能的影响，并对吸附后的复合抗菌材料进行了稳定性的研究，为制备性能优异的复合抗菌材料提供实验基础。主要研究内容与结果包括： 1．MgO纳微结构的制备研究 (1)以Mg(NO3)2.6H2O为镁源，(COOH)2.2H2O为沉淀剂，通过掺杂引入Ti4+、Cu2+(Cu+)、Li+和Zn2+四种不同的价态的金属离子，制备出高比表面积、颗粒尺寸小分散性好的纳米MgO。研究发现这些金属离子能进入MgO晶格，并引起晶面间距增大，BET、PL谱、XPS等分析测试表明掺杂引起各类缺陷增多，并抑制晶粒生长，晶粒尺寸由20nm左右降至3-5nm，比表面积明显增加。 (2)在不添加任何模板剂的条件下，通过水热过程工艺制备了颗粒尺寸在十几个微米，孔径在9.5nm，比表面积114.6m2/g的介孔MgO，并研究了其生长过程以及可能的形成机理；采用MgCl2.6H2O和N2H4.2H2O为原料，分别在25℃和100℃合成后，煅烧温度500°C，制备了多孔氧化镁纳米片并提出了可能的生长机理，可以通过调节反应温度和时间来控制多孔氧化镁纳米片结构；采用乙酸镁和草酸，600°C下氮气气氛制备了比表面积203.3m2/g自组装介孔MgO。 2．不同结构的MgO的吸附性能研究 (1) 对氯气的吸附。掺杂Ti4+、Cu2+(Cu+)、Zn2+和Li+四种金属离子制备的MgO对氯气的吸附实验表明，掺杂后的对氯气的吸附量明显高于纯MgO的，且2%mol掺杂的MgO样品对氯气的吸附能力最强，对吸附的模拟发现，准二级速率模型更适用于氯气在氧化镁纳米颗粒的动态吸附。多孔MgO对氯气在24h的吸附实验表明，多孔MgO对氯气的吸附能力也明显高于纯的MgO。对吸附氯气后与KBr混合后的压片实验表明，吸附在氧化镁上的氯气还原溴离子使其成为溴，这说明在MgO上的大部分氯气未与MgO发生化学反应，而是物理吸附的模式。尺寸在十几个微米的多孔M1样品中的孔洞具有毛细管力，使得氯气是逐步释放的。 (2)对三氯生的吸附。所制备的纳米级尺寸MgO均对三氯生有吸附能力，但尺寸在十几个微米的多孔M1样品对三氯生没有吸附能力。掺钛和掺锌的氧化镁的对浓度为60mg/L三氯生的吸附能力高于纯MgO粉体，掺铜的略小于纯MgO粉体，而掺锂的则吸附能力明显下降，且随掺锂量的增大而减弱。 3．不同结构MgO的抗菌实验和复合材料稳定性研究 (1) 掺杂后的纳米MgO粉体15min的抗菌率明显高于纯MgO的，24h的抗菌率则均为99.99%，掺铜的MgO粉体的15min抗菌性能最好，其次是掺锂和掺锌的，再次为掺钛的。这主要是由于掺铜的样品除了比表面积更大，颗粒尺寸更小外，铜离子本身还具有杀菌能力，使得掺铜样品的抗菌性能更好。纳米粉体的抗菌过程主要如下，带有正电的纳米级的氧化镁吸附在微米级带有负电的细菌表面，然后本身的碱性以及由氧空位所形成的活性氧侵蚀细菌的细胞壁，然后几个纳米的粉体进入细菌内部，破坏细菌，使得细菌变形，从而杀死细菌。 (2) MgO-Cl2加合物的快速杀菌实验表明，对大肠杆菌和金色葡萄球菌15min的快速灭杀率在99%，对枯草芽孢杆菌的抗菌率，2Ti-MgO-Cl2和2Zn-MgO-Cl2的15min抗菌率在80%以上。对MgO-Cl2加合物储存一定时间压片后对大肠杆菌的抑菌圈实验发现，在常温常压下储存12个月，加合物仍有很强的溶出抑菌性，这说明加合物稳定性好，因此MgO-Cl2的加合物可以在实际中得到应用。 (3) 对MgO-Tri复合材料在250°C空气中煅烧30min后复合样品仍有很强的溶出抑菌性能，当煅烧温度到300°C，复合材料的溶出抑菌性变的很差，说明在这个温度下复合材料中的三氯生发生了分解或者挥发，使得三氯生的含量变的很低。因此这种复合材料有可能应用在需要200°C左右进行加工处理的抗菌塑料中。 |
| 英文摘要 | As a multifunction inorganic material, MgO has broad application prospect in many fields, especially in antimicrobial material which are correlated with health of human beings. Due to the presence of its well-defined surface defect structure that includes low-coordination ions and/or vacancies on the surface, magnesium oxide can adsorb other antibacterial agents prepared composite materials, so the composite materials have broad-spectrum, efficient and quickly kill or inhibiting bacteria, spores and viruses. In this paper, by doping different valence metal ions to MgO system, we prepared nano-sized MgO with small size, large surface area and good adsorption properties. We prepared several different type porous MgO by simple methods. Then the influences of doping on the structure, morphology, the adsorption and antibacterial properties of MgO powder were investigated. The stability of composite antibacterial materials were studied. This provides an experimental basis for the application of composite antibacterial material. On the basis of experimental results, this work mainly includes the following aspects: 1. Preparation of nano-sized and micro-sized MgO structure (1) The preparation of nano MgO particles with high specific surface area and highly active: Mg(NO3)2.6H2O as magnesium, (COOH)2.2H2O as the precipitating agent, by doping Ti4+, Cu2+(Cu+), Li+ and Zn2+ ions, we prepared ions-doped nano MgO with high surface area, small particle size and good dispersion. We found these metal ions can enter MgO and cause lattice spacing increased. The results showed that doping ions caused various types of defects, inhibit grain growth and surface area increased. (2) Preparation of porous MgO microstructure by self-assembly. Mesoporous MgO with micron particle size, pore size 9.5nm, specific surface area of 114.6m2/g was prepared by hydrothermal method at 160°C for 24h, the growth process and possible formation mechanism were studied. Nano porous MgO sheet were synthesized by chemical co-precipitation method using MgCl2 solution as the magnesium source and hydrazine hydrate as precipitant at 25℃and 100℃，calcined at 500°C for 2h. A possible formation and crystal growth mechanism of MgO is proposed. Self-assembled mesoporous MgO with specific surface area 203.3m2/g were prepared by acetic acid and magnesium oxalate. 2. Adsorption performance of MgO with different structures (1) Adsorption of MgO for chlorine. The experiment results of Ti4+、Cu2+(Cu+)、Zn2+ and Li+ doped MgO adsorbed chlorine showed that: adsorption amount of chorine doped-MgO significantly higher than pure MgO, and the chlorine adsorption capacity of 2%mol ions-doped MgO is strongest; Pseudo-second-order fits well in describing the chlorine in MgO nanoparticles dynamic adsorption process. Adsorption capacity of porous MgO were also significantly higher than pure MgO. Bromide ion is capable of reduced by Chlorine gas adsorbed on MgO. This indicates that most of chlorine gas was not chemically react with MgO, it only physical adsorption. (2) Adsorption of triclosan. Prepared nano-sized MgO can adsorb triclosan, but microns cannot adsorb triclosan. The adsorption capacity of Ti-doped MgO and Zn-doped MgO for 60mg/L significantly higher than pure MgO powder, but adsorption capacity of Li-doped MgO significantly less than pure MgO powder. 3. MgO antibacterial experiments and stability study on composite materials (1) Antibacterial rate for 15min of doped-MgO was significantly higher than pure MgO. The antibacterial rate for 24h all were 99.99%. Antibacterial properties for 15min of Cu-doped MgO powder are best, followed by Li-doped MgO and Zn-doped MgO. This is mainly due to copper ions have antibacterial properties, so that the antibacterial properties of Cu-doped MgO sample are better. Antibacterial process of MgO nanopowders follows, positively charged nano MgO adsorbed on miron bacterial surface with negatively charged, and then active oxygen formed by |
| 语种 | 中文 |
| 公开日期 | 2015-07-08 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/15511]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 崔洪梅. 纳米结构MgO粉体的制备与性能研究[D]. 中国科学院研究生院. 2014. |
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