| Title |
Effect of Pretreatment of Biogenic Titanium Dioxide on Photocatalytic Transformation of Chloroform |
| Authors |
권수열 ( Soo Youl Kwon ) ; 김영 ( Young Kim ) ; ( Greg Roorrer ) ; ( Lewis Semprini ) |
| Keywords |
Chloroform; Diatom-produced biogenic TiO2; Photocatalysis; Titanium dioxide |
| Abstract |
Photocatalysis using UV light and catalysts is an attractive low temperature and non-energy-intensive method for remediation of a wide range of chemical contaminants like chloroform (CF). Recently development of environmental friendly and sustainable catalytic systems is needed before such catalysts can be routinely applied to large-scale remediation or drinking water treatment. Titanium dioxide is a candidate material, since it is stable, highly reactive, and inexpensive. Diatoms are photosynthetic, single-celled algae that make a microscale silica shell with nano scale features. These diatoms have an ability to biologically fabricate TiO2 nanoparticles into this shell in a process that parallels nanoscale silica mineralization. We cultivated diatoms, metabolically deposited titanium into the shell by using a two-stage photobioreactor and used this biogenic TiO2 to this study. In this study we evaluated how effectively biogenic TiO2 nanoparticles transform CF compared with chemically-synthesized TiO2 nanoparticlesthe and effect of pretreatment of diatom-produced TiO2 nanoparticles on photocatalytic transformation of CF. The rate of CF transformation by diatom-TiO2 particles is a factor of 3 slower than chemically-synthesized one and chloride ion production was also co-related with CF transformation, and 79~91% of CF mineralization was observed in two TiO2 particles. And the period of sonication and mass transfer due to particle size, evaluated by difference of oxygen tention does not affect on the CF transformation. Based on the XRD analysis we conclude that slower CF transformation by diatom-TiO2 might be due to incomplete annealing to the anatase form. |