Description
Synthesis of pure anatase TiO 2 with particle sizes smaller than 100 nanometers has been one
of the focuses in the area of photocatalysts. In order to achieve the desired chemical
compostion and particle size, appropriate initial reagents are required. This study aimed at
examining effects of sol-gel intitial reagents, specifically titanium (IV) isopropoxide (TTIP),
sub-micrometer- sized titanium dioxide dissolved in sulfuric acid, and titanium dioxide
dissolved in sulfuric acid with addition of polyacrylic acid, on chemical compositions and
particle sizes of TiO 2 powders. Experimental results indicated that preparation of nano-
particulate titanium dioxide, with the average size ranging from 48 to 85 nanometers, could
be achieved when using TTIP and sub-micrometer- sized titanium dioxide dissolved in
sulfuric acid with addition of polyacrylic acid as initial reagents. The results also revealed
that the finest average particle size was attained in the powder prepared from TTIP. For the
powder prepared from sub-micrometer- sized titanium dioxide dissolved in sulfuric acid
without addition of polyacrylic acid, larger particle sizes with an average of 130 nanometers
were present. In addition, formation of a secondary phase, identified as titanium oxide
sulfate, was observed. Chemical compositions as well as particle sizes were discussed with
respect to structures of the initial reagents and polymerization reactions potentially occurred
during the sol-gel process. Antibacterial activity of the powder prepared from sub-
micrometer-size titanium dioxide dissolved in sulfuric acid with addition of polyacrylic acid
was evaluated. Reduction of Staphylococcus aureus by more than 99.9% was observed.
