微反应器法纳米粒子的合成及其智能性研究
作者：黄海燕
院校:北京化工大学
关键字:微反应器,纳米微粒,合成,智能性
学位：硕士
专业:应用化学
摘要:
在微反应器内合成得到TiO2纳米微粒,用透射电子显微镜(TEM)法、冷冻TEM法、染色TEM法及UV-VIS吸收光谱法研究了原始反应过程和5次母液直接回收利用过程,证明微反应器系统由无数个微反应器组成,发现单个微反应器内部和外部均呈球形或椭球形结构,其大小为纳米级,具体尺寸可根据需要通过试验条件特别是含水量条件人为控制。纳米粒子合成之后,微反应器在离心分离出纳米粒子的过程中受到了破坏,但又自动修复或重新组合,修复后的微反应器仍为球形或椭球形结构,只是由于含水量的增加使其尺寸增大。在补充了反应过程中损失的物质之后,反应后的微反应器能够迅速修复到原始状态,并能制得相同粒径的纳米TiO2粒子。纳米TiO2粒子在修复的微反应器和原始微反应器中的生长历程和生长速度一致,显示了记忆功能。试验结果为微反应器的智能性提供了有力证据。 根据Brus公式,由不同时刻反应液的最大吸收波长,计算得到不同时刻TiO2纳米粒子的半径,直观地反映了粒子的尺寸随时间的变化情况,以此来研究粒子生长的动力学。 以1-6次循环回收母液为原料,进行减压蒸馏,定量测定回收液中各组分的含量,以了解微反应器循环利用在纳米微粒的合成上的经济意义。 用同一种微反应器体系还可以得到α-Fe2O3纳米粒子。这也是微反应器智能性的另一方面的体现。
Abstract:
The objective of this study was to synthesize TiO2 nanoparticles in micro-reactors. TiO2 nanometer particles were synthesized by recovering micro-reactors mother-liquid directly. Reacting process in origin and in 5 times mother-liquid recovered directly were studied by transparent emission micrograph (TEM) method, dyeing TEM method and UV-VIS absorption spectrum method. We found that micro-reactor system was made up of uncountable single micro-reactors whose inner and outer shape both were sphere or oval structure, and whose size is nanometer grade. Size of micro-reactors could be controlled deliberately by experimental condition especial water content. Micro-reactors were destroyed during centrifuge separation after synthesized nanometer particles, but they could restore automatically or reassembly. Micro-reactors restored still were sphere or oval structure, but their size enlarged because water content increased. Micro-reactors could restore into origin state. TiO2 nanometer particles with the same size as in origin micro-reactors were obtained. Growth course and growth speed in restored micro-reactors were consistent with that in origin micro-reactors, which showed remember function. The experimental results provided powerful evidence for intelligent of micro-reactors. Radius of TiO2 nano-particles which systhesized in different reaction time were acculated by maximum absorbence wavelength according to Brus equation, which could show variation of size with reaction time, and mechanise were studied. Decompressed distillation was executed by recovered for 1-6 times mother-liquid as input material, the content of components was determined quantitatively. It could make us to understand the economic significance of micro-reactors being reclyed in synthesizing nano-particles. α-Fe2O3 was systhesized in micro-reactors system similar as TiO2. It was the other embodiment of the intelligent property of micro-reactors.