| Abstract |
| High purity TiO2 nanocrystals (rod shape, ≤ 100 nm) were synthesized from TTIP/H2O2/H2O systems, and utilized as photocatalysts for degradation of humic acid (HA) in the aqueous solution. The high purity TiO2 nanocrystals were obtained by excluding the use of inorganic acids that might consequently cause contamination of active catalytic surface sites of the nanocrystals by Cl-, NO3- and SO42-. Particle size and crystallinity of the nanocrystals were increased with progressing the refluxing time 1~9 h at 120℃ in an oil bath. By varying H2O2/Ti = 5.5~55, the crystalline phase of anatase/rutile ratio of the nanocrystals was controllable. The photocatalytic properties of the nanocrystals were strongly dependent upon the crystallinity and particle size. The dissolved organic carbon (DOC) removal of humic acid was most effective for the nanocrystals prepared at H2O2/Ti = 5.5 due to the mixed crystalline phase of anatase/rutile and the increased surface area by smaller particle size. The decreases of UV254 absorbance of HA solutions, which is caused by the conjugate double bond breakage, were much faster than those of DOC, and not so dependent upon the variations of TiO2 nanocrystals. |
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| Key Words |
| TiO2 nanocrystals, photocatalyst, humic acid, TTIP, H2O2, H2O systems |
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