微乳法合成纳米ZnCO₃、ZnO的研究

【作者】 冯悦兵；

【导师】 卢文庆；

【作者基本信息】 南京师范大学 ， 物理化学， 2003， 硕士

【摘要】 本论文研究纳米碳酸锌和纳米氧化锌的制备、表征和性能。用微乳法合成了纳米碳酸锌和纳米氧化锌，对二者的形貌、大小、粒度分布等进行了表征；测定了纳米碳酸锌热分解反应动力学参数；研究纳米氧化锌在紫外-可见光区域的吸收性能，得到了比较好的结果。 我们选择由CTAB／正丁醇／正辛烷／盐溶液组成的微乳体系，首先用马尔文粒度测定仪对含硝酸锌和碳酸铵的W/O型微乳液反胶束中液滴的大小进行了表征。测定结果表明，微乳液中液滴大小均匀，分布很窄，直径分别在6.2～12.4nm和4.9～7.7nm之间，非常适合作纳米反应器宋制备纳米粒子。分别改变表面活性剂和反应物的浓度，制备出了1号、2号和3号纳米碳酸锌。用透射电子显微镜观察1号、2号和3号纳米碳酸锌粒子，可以看到粒子形状为椭球形，大小均匀，分散性好，没有明显的团聚现象，粒径分别在20～40nm、6～10nm、5～8nm之间；并且用微粒度测定仪测得了粉体的粒度分布图，表明纳米碳酸锌粒子的分布很窄。由实验测定结果经过计算得到纳米碳酸锌分解反应的活化能为110kJ.mol^-1，相应的反应级数为0.9级。 将制得的纳米碳酸锌在一定温度下分解就得到了纳米氧化锌。所制得的产物经X-射线衍射结果证实，与六方氧化锌的JCPDS卡符合很好；运用透射电子显微镜对所制得的氧化锌的粒径进行了表征，发现氧化锌分散性很好，少团聚，粒度分布均匀，粒径在5～40nm之间；粒度分布测定结果表明，纳米氧化锌粒子的分布很窄。实验事实表明：在制备纳米粒子方面，微乳法有其独特的优点。 本论文最后对纳米氧化锌的紫外-可见光吸收性能进行了研究。实验结果表明：纳米氧化锌具有特殊的光学性能，即在可见光区有良好的透光率，在紫外区表现出强的宽带吸收，特别对长波紫外线有很强的吸收能力。利用纳米氧化锌在紫外区有强的宽带吸收的特性，可单独使用纳米氧化锌作为防晒剂成分就能高效吸收紫外线保护皮肤。更多还原

【Abstract】 This thesis studied on the preparation, characterization and capability of nanosized zinc carbonate and zinc oxide. Using microemulsion method, we synthesized nanosized zinc carbonate and zinc oxide, which were characterized for the morphology, size and particle size distribution etc. The kinetic parameters of thermal decomposition reaction of nanosized zinc carbonate were determined, while the absorptivity of ultraviolet and visible light of nanosized zinc oxide in aqueous solution was studied.The microemulsion system has been chosen that consisted of CTAB/butanol/ octane/saline solution. The influences of the concentration of the surfactant and reactant on the diameter of nanoparticles were studied and the kinetic parameters of thermal decomposition reaction were determined. It can be shown from experimental results, the diameter of the droplet in the W/O microemulsion which have dissolved reactant zinc nitrate and sal volatile is between 4.9 nm and 7.7 nm, 6.2 nm and 12.4 nm, respectively. Nanosized zinc carbonate prepared by the method of microemulsion has shown good dispersion, narrow distribution and light agglomeration. The particle size of nanosized zinc carbonate is between 5 nm and 40 nm, and its kinetic parameters of thermal decomposition reaction-activation energy E and reaction order n are 110 kJ.mol-1 and 0.9, respectively.Nanosized zinc oxide was obtained by decomposing nanosized zinc carbonate that had been prepared. XRD showed that the data of the product accorded with those of JCPDS card of hexagonal zinc oxide. TEM showed that the prepared zinc oxide particles with diameter in the range of 5 ?40 nm had good dispersion, light agglomeration and uniform distribution. It was showed from the determinable results of the size distribution that nanosized zinc oxide had narrow distribution. The experimental facts indicated that the microemulsion method has its particular merits in the aspect of preparing nanosized particles.This thesis finally studied on the absorptivity of ultraviolet and visible light of nanosized zinc oxide in aqueous solution. The experimental results showed that nanosized zinc oxide has the particular optical performance, namely it has good transparency in visible light zone, and exhibits strong wide band absorption in ultraviolet zone, especially has very strong the capability of absorption to UVA with 360 ~ 380 nm. Using thecharacteristic of strong wide band absorption of nanosized zinc oxide in ultraviolet zone, it can be alone employed as the component of sun-screening agent to protect the skin by efficiently absorbing the ultraviolet ray.更多还原