메조포러스 TiO₂의 제조 및 이를 응용한 광활성 연구

Abstract

본 연구에서는 표면적이 넓고 결정성이 우수한 TiO₂를 제조하여 메틸렌블루 분해실험 및 항균성능 테스트 등을 통하여 광촉매의 광활성 효율을 평가하였다. 표면적을 넓게 하기 위하여 메조포러스 TiO₂를 계면활성제를 이용한 졸-겔법으로 합성하였다. 또한 이렇게 합성된 메조포러스 TiO₂를 가수열 반응을 통하여 결정성이 우수한 TiO₂를 제조하였다. 제조된 메조포러스 TiO₂는 메틸렌블루 분해를 이용하여 광효율을 분석하였다. 이는 기존의 상업적으로 알려져 있는 Degussa P25 TiO₂의 광분해 효율보다 약 6배 이상 빠른 광분해 효율을 보였다. 또한, 항균성능을 테스트하기 위하여 광-필름밀착법을 이용하여 E. coli 항균 실험을 한 결과, 기존의 TiO₂보다 약 5배 이상 빠른 항균성능을 보였다. 이러한 결과는 메조포러스 TiO₂가 가지는 넓은 표면적과 결정성이 우수한 성질에서 나타나는 결과로 해석되며, 상업적으로 활용이 가능하다는 것을 보여주고 있다. 이러한 메조포러스 TiO₂는 기존의 TiO₂가 응용되고 있는 수질정화기능, 공기정화기능 및 악취물질 제거 기능 등에 대체 물질로 사용될 수 있으므로, 본 연구와 같은 방법으로 TiO₂를 제조시, 상업적으로 활용될 수 있는 가능성을 보여주었다.;Titanium dioxide is a well-known photocatalyst for waste water treatment and air purification as well as for photocatalytic di-infection of micro-organisms. The general process for the photocatalytic destruction of organic molecules begins with the excitation by bandgap energy photons, and it continues through redox reactions where OH radicals, formed on the photocatalyst surface, play a major role. Although TiO₂ has been widely used in various fields, the efficiency of photocatalytic activity is not sufficient to be used in industry due to the cost. Therefore, new synthetic concept of TiO₂ which has a high photocatalytic activity has been studied. The photocatalytic activity of TiO₂ is one of the most distinctive features, and is mainly related to the properties such as specific surface area and crystallinity. TiO₂ with a large surface area and a porous structure is expected to exhibit outstanding photodegradation properties, because TiO₂ with a large surface area has many active sites so that substances can be adsorbed in large quantities onto the TiO₂surface, and it's porosity facilitates pollutant access, adsorption, and decomposition. The crystallinity of TiO₂ also affects the photocatalytic activity because an electron, excited from a valence band to a conduction band, generate the electron hole pair. Thus, in this study, mesoporous TiO₂ with large surface area and high crystallinity was synthesized. Photocatalytic activity of methylene blue degradation and disinfection test of E. coli were investigated. The photocatalytic activity of mesoporous TiO₂ was characterized with UV-Vis spectroscopy, and it was found to be 5.8 times higher than that of Degussa P25 TiO₂(P25). For deactivation of Escherichia coli, mesoporous TiO₂ showed a high photocatalytic activity than that of P25. Such a high photocatalytic activity could be explained with the large surface area and the small crystal size with a high crystallinity. This study shows that the mesoporous TiO₂ would be applied to various fields such as air purification and wastewater treatment in near future.