Preparation Of Full Rutile Nano-TiO₂

Nanometer TiO2 has attracted wide attention of people to its preparation owing to its excellent physical performance, chemical properties and widely application prospects. In this paper, nano-TiO2, whose grain size is small and crystalline phase is controllable , is prepared by Hydrothermal method based on the merits of liquid-phase methods. This paper studied the influence of hydrothermal time and temperature for hydrothermal treatment as well as adding surfactant on the grain size and crystalline phase through XRD, IR and TEM technique.The preparation of sol is one of the most important steps to preparation of nano-TiO2. It is necessary for perfect ,small ,and good dispersivity crystalline to peptize the white precipitates of hydrolysis Ti(SO4)2 by using the aqueous solutions of HC1 or HNO3 whose concentration is in scope of 0.5mol/L to 2mol/L in the rang of 40 to 80 . And we found the colloid particles are electropositive.In the process of hydrothermal treatment , the temperature of the system has the most important effect on the crystallization of the product. The XRD spectrum shew that Lower temperature favors the growth of Anatase ,while higher temperature favors the well crystallized Rutile in product. To obtain as more Rutile as possible and the most crystallized nano-particle , the reaction temperature must be controlled at least 180 for 8h.Through the TEM image of samples we found that the degree of dispersion of nano-TiO2 is improved and the crystalline is more perfectafter adding surfactant. The surfactant absorbed on the surface of colloid particle hinders the colloid particles collision, which can result in the amorphism, and confines the growth of the grain. What is more , the surfactant may change the apparent activation energy of growth and phase transformation from anatase to rutile and remarkably improve the degree of the crystallization and the content of the rutile based on the model of the growth unit of negative complex polyhedron.In this paper we got the full nano-rutile with perfect crystalline, good dispersivity and size from 15 30 to 30 100nm by adding TAB and LHX without calcining. The optimum addition level is [surfactant]:[Ti4+] = 1:20.