Preparation And Properties Of Several Nano Functional Materials

Nanotechnology, information technology and biotechnology will become the three pillars centuries in the development of social and economic. Nanometer material is the basis of nano science and technology, and the nano functional material is the most dynamic areas of nanometer materials science. It is considered the nano functional material will have far-reaching influence on the information, biology, energy,environment, aerospace and other high-tech areas, and has a broad application prospect.Adsorption materials are widely used in the dye wastewater treatment. The pollutants are adsorbed on the surface for further treatment because of their high surface activity. Comparing with the conventional adsorbent, the micro/nano materials have revealed larger adsorbing capacity and faster rate of adsorption. In recent years,the excellent performance of new micro/nano adsorption material of various kinds are springing up constantly, improve and perfect the adsorbent in treatment of dye pollution, and show a good application prospect.With the development of social and industrial progress, high heat flow has brought new challenges on heat transfer and refrigeration technology. Nanofluid get through dispersing nanoparticles in pure fluid（water, ethylene glycol, and heat transfer oil etc）.Compared with the traditional fluid, nanofluid is expected to become a new generation of heat transfer fluid due to its excellent thermal conductivity enhancement,and applied in micro-heat exchangers, transportation, aerospace, micro-electronics and medicine to improve the economy, reliability and miniaturization of the heat exchange system. In order to solve these problems, the major research contents in this thesis are mcro/nano adsorbent and nanofluids. The high efficiency adsorbent was synthesized based on hydrothermal process. And the oil based nanofluids are prepared based on surface modification technology, then their conductivities are studied. The main research results are as follows:1、Aluminum sulfate, urea, and oleic acid are used as raw materials, and three kinds of structures（solid, capsule and hollow） of AlOOH are synthesized by hydrothermal method in the water/ethanol system only by adjusting the temperature and reaction time. Then the AlOOH are calcined to get Al₂O₃ mcro/nano materials. Water treatment performance test show that the solid Al₂O₃ has the strongest adsorption for Congo red dye, and the material can be recycled. So this Al₂O₃ mcro/nano material is expected to be a new-type dye wastwater treatment material.2、Hydrophobic CuS nanoparticles with stearic acid as ligands are synthesized via two-phase method. The nanoparticles were characterized by XRD, TEM, FTIR and TG etc. Results show that the surface modified nanoparticles exhibit a rather uniform size distribution due to the organic capped-layer chemically linked on the surface of the nanoparticles. Owing to the hydrophobic property of the organic modification layer, the CuS nanoparticles show excellent lipophilicity and stability in weak polar organic solvents.3、Different volume fractions of oil based nanofluids were prepared by dispersing the as-prepared CuS nanoparticles and commercial modified SiO₂ nanoparticles into heat transfer oil, respectively. Based on the UV-vis study, both the oil based nanofluids exhibit satisfactory dispersion stability.4 、 The thermal conductivity and viscosity of both nanofluids are measured using KD2 pro Thermal Properties Analyzer and digital viscometer, respectively. It is observed that the viscosities only slightly enhance with increasing volume fraction of these nanofluids, and reduce with increasing temperature as same as the base oil.However, the thermal conductivities of these nanofluids increase as the nanoparticleconcentrations increase. The maximum enhancement of thermal conductivity of0.04% CuS oil-based nanofluids is 20.5% at 30℃, while SiO₂ oil-based nanofluids shows 12.8% enhancement with the same volume fraction. So it can be expected that such novel heat transfer carriers has a broad application prospect for the heat exchange system and will greatly enhance the heat transfer performance.5、Finally, the mechanism of heat transform enhancement of the heat transfer oil-base nanofluid is primitively proposed, and compared with some classic theoretical models.