Biogenic TiO_2 나노입자 전처리가 클로로포름 광분해에 미치는 영향

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 TiO_2 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 TiO_2 to this study. In this study we evaluated how effectively biogenic TiO_2 nanoparticles transform CF compared with chemically-synthesized TiO_2 nanoparticlesthe and effect of pretreatment of diatom-produced TiO_2 nanoparticles on photocatalytic transformation of CF. The rate of CF transformation by diatom-TiO_2 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 TiO_2 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-TiO_2 might be due to incomplete annealing to the anatase form.