부영양화된 수중에서 중공유리구 광촉매를 이용한 조류증식 억제

이동근·강민수·정익상·조인철·우승희·김성철·김성우*

경상대학교 화학공학과/환경보전학과, 환경보전연구소

*삼협자원개발(주)

Photocatalytic Inactivation of Algal Growth in Eutrophic Water

with Hollow Glass Beads

Dong-Keun Lee, Min-Su Kang, Ik-Sang Chung, In-Cheol Cho, Seung-Hee Woo, Sung-Chul Kim and Sung-Woo Kim*

Department of Chem. Eng./Environ. Protection, Research Institute of Environmental Protection, Gyeongsang National Univ., *Samhyup Resource Development Co.

TiO2 in the anatase crystal  form is a semiconductor with a bandgap of 3.2eV or more. Upon excitation by light of wavelength less than 385nm, the photon energy generates an electron-hole pair on the TiO2 surface. This electron-hole pair produces highly reactive oxygen species. The application of photocatalyts to destroy organic pollutants from contaminated air or water have been extensively studied. Microbial cells in water were reported to be killed by the action of TiO2 photocatalysis. This finding gave us an insight that the inhibition of fast growth of algae in eutrophic water can be accomplished by applying the photocatalytic activity of TiO2. Although the problems by algal bloom in eutrophic water are nowadays serious to our life, only a few researches on the removal of algae which causes clogging in filtration process and odor and taste problems in drinking water have been reported.

TiO2 photocatalyst immobilized on the surface hollow glass bead was employed for the photocatalytic control of the growth of algae in water. TiO2 was coated on the surface of the hollow glass beads through a sol-gel method. TiO2 could successfully be coated on glass with thickness of about 0.3□. The TiO2 surface was highly porous and the film was extremely stable physically and/or chemically. When the surface of TiO2  film was analyzed with XRD, most of the TiO2 was found to be in form of anatase.

Photocatalytic inactivation of algae, Anabaena, Microcystis, and Melosira, was carried out with the TiO2-coated pyrex glass beads under the illumination of UV light(370nm wavelength). After being irradiated with UV light in the presence of the TiO2-coated pyrex glass beads, Anabaena and Microcystis, known as typical cyanobacteria, lost their photosynthetic activity, and the string of Anabaena cells and the colonies of Microcystis cells were completely separated into individual spherical one. In the case of Melosira which is a typical diatom, however, somewhat lower photocatalytic inactivation efficiency was obtained, which was believed to be due to the presence of the inorganic siliceous wall surrounding the cells of Melosira.