Study of the Sintering of Nanosized Titania Agglomerates in Flames UsingIn SituLight Scattering Measurements

Abstract

OH 4 5 2 2 2 1 -0 0 7 1 ABSTRACT. A premixed flame aerosol reactor was used to produce titania particles by oxidation of titanium isopropoxide vapor. The growth, aggregation of particles, and the agglomerate structure were determined as a function of height in the flame using in situ light scattering and transmission electron microscopy (TEM) measurements. A methodology to determine the sintering characteristic time using light scattering data was established. The light scattering data provided the evolution of the fractal dimension which was then related to the normalized surface area change using a computer simulation. The sintering equation was redeveloped in terms of the normalized surface area, thus not having to account for coagulation effects. Experimental results indicate that isolated titania particles were observed at the high temperatures due to fast sintering. An agglomerate was obtained at downstream locations with an associated change in fractal dimension due to sintering.

A One-Dimensional Model for Coagulation, Sintering, and Surface Growth of Aerosol Agglomerates

“…The above expression, which differs significantly from Equation (28), was independently verified in other experiments (Yang and Biswas 1997). Predictions made using Equation (29) agreed well with measurements ( Figure 9).…”

Control of Toxic Metal Emissions from Combustors Using Sorbents: A Review

“…Several reports exist on the formation of inorganic oxides in high-temperature environments. 105,173 Yang and Biswas 174 have performed extensive light-scattering measurements to evaluate the sintering characteristics of titania particles. A comparison of characteristic times for formation by chemical reaction, coagulation, and sintering can be used to ensure that large agglomerated structures with very high surface areas form in the combustor.…”

Characteristics of Titania Nanoparticles Synthesized Through Low Temperature Aerosol Process

“…Two different chemical precursors have been typically used in these investigations namely, titanium tetra chloride (TiCl 4 ) and titanium tetra isopropoxide (TTIP). In high temperature processes, particles can be synthesized either by the oxidation of TiCl 4 (Suyama and Kato 1976;Morooka et al, 1989;Akhtar and Xiong, 1991;Akhtar and Vemury, 1994;Jang and Jeong, 1995;Yang et al, 1996;Yang et al, 1997;Windeler and Friedlander, 1997), or by the hydrolysis of TiCl 4 (Akhtar and Vemury,1994;Xia et al, 1999a,b) or by the thermal decomposition of TTIP (Komiyama and Kanai, 1984;Okuyama et al, 1986;Okuyama et al, 1990) or by the hydrolysis of TTIP (Wu et al, 1998;Kirkbir and Komiyama 1988;Chan et al, 1999). Recently, considerable interest has been directed towards the synthesis of titania at low temperatures based on aqueous phase processing (Kim and Park, 1999;Park et al, 1999;Li and Fan, 2002;Yin et al, 2002;Tang and Zhang, 2002;Yang, 2003).…”