Characteristics of Micromixing Efficiency and Synthesis of Magnesium Hydroxide Nanoparticles in a Rotating Packed Bed Equipped with Blade Packings

• Main Authors: Cheng Hua Tsai, 蔡政華
• Other Authors: C. C. Lin
• Format: Others
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/37876872869803570772

碩士 === 長庚大學 === 化工與材料工程研究所 === 96 === Owing to that the micromixing efficiency of the devices based on high-gravity (Higee) technology is superior to other mixing devices, it is very important to utilizing Higee technology for synthesizing nanoparticles. Characteristics of micromixing of a rotating packed bed (RPB), spinning disk reactor and rotor–stator reactor have been widely studied in literatures. However, investigation concerning about the micromixing in the RPB equipped with blade packings is not found in the literatures. This work investigated characteristics of micromixing of the RPB equipped with blade packings using the iodide-iodate reaction system. Experimental results indicated that increasing the outer radius of the packing had no significant effect on micromixing efficiency. Also, micromixing efficiency increased with increasing rotor speed and liquid flow rate but decreased with increasing the inner radius of the packing and reducing blade number. In addition, micromixing efficiency was not influenced by liquid viscosity. This work also adopted the RPB equipped with blade packings to synthesize nanoparticles of magnesium hydroxide with magnesium chloride and sodium hydroxide. Experimental results indicated that mean size of magnesium hydroxide would decrease as the reactant concentration was increased. The superior dispersion of magnesium hydroxide was observed at the ratio of reactant flow rate of 1:1. At the rotor speed of 600 rpm, the RPB equipped with blade packings provided the smallest size of magnesium hydroxide of 44.1 nm. Moreover, the mean size of magnesium hydroxide would increase as the rotor speed was increased. The morphological structure of magnesium hydroxide nanoparticles were not changed by adding PEG 1000 or SDBS to sodium hydroxide solutions as dispersing agents and replacing sodium hydroxide with ammonia water, but adding PEG 1000 or SDBS would reduce the degree of crystal of magnesium hydroxide nanoparticles.