• Journal of the Korean Ceramic Society
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• v.38 no.7
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• pp.621-627
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• 2001

알루미나 졸에 평균 25nm의 TiO$_2$(Degussa P25) 광 촉매 분말을 분산하여 광촉매 코팅제를 제조하였다. 점도 약 24 cps를 가지 4.4 wt%의 알루미나 졸로부터 약 300nm 두께의 코팅막이 제조되었으며, 졸 점도의 증가에 비례하여 코팅막의 두께도 증가하였다. TiO$_2$광 촉매의 코팅용 바인더로 이용한 알루미나 졸의 결정형은 25~30$0^{\circ}C$에서 pseudo boehmite (AlOOH)이었으며, 50$0^{\circ}C$ 이상에서는 ${\gamma}$-Al$_2$O$_3$으로 전환되었다. AlOOH/TiO$_2$코팅막은 oleic acid와 humic acid에 대한 기상 및 수상 조건에서의 광 촉매 실험에서 우수한 유기물의 광분해 효능을 나타내었다. 아울러 EGI(Electro-Galvanized Iron)에 코팅된 AlOOH/TiO$_2$코팅막은 내식성 및 내지문성의 효과도 부수적으로 나타내었다.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1073-1081
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• 2000

The photo-oxidation of an aqueous humic acid solution using $TiO_2$ sols. which is transparent in visible range, was studied. The $TiO_2$ sols were prepared by a process wherein hydrogen peroxide was added to a gel of $TiO(OH)_2$ originated from hydrolysis of $TiCl_4$, and the resulting titanium peroxo solution(TPS) was heated. The concentration of $TiO_2$ used for photo-oxidation was about 100ppm, determined by comparing the photoluminescence(PL) intensity measured as a function of $TiO_2$ concentration. $TiO_2$ sols aged at $100^{\circ}C$ for more than 12h were found to exhibit a maximum rate in photocatalytic decomposition of humic acid. and the efficiency was better than that of Degussa P25. In addition, the resulting aqueous humic acid after photocatalytic decomposition with sols had an excellent transmittance of visible light, while that treated with Degussa P25 was still turbid. caused by $TiO_2$ particles.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.129-136
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• 2011

Recently studies on functional concrete with a photocatalytic material such as $TiO_2$ have actively been carried out in order to remove air pollutants. The absorbtion of $TiO_2$ from those studies is applied by it being directly mixed into concrete or by suspension coated on the surface. When it comes to the effectiveness, the former process is less than that of the latter compared with the $TiO_2$ use. As a result, the direct coating of $TiO_2$ on materials' surface is more used for effectiveness. The Surface spread of it needs to have a more than $400^{\circ}C$ heat treat done to stimulate the activation and adhesion of photocatalysis. Heat treat consequently leads hydration products in concrete to be dehydrated and shrunk and is the cause of cracking. The study produces $TiO_2$ used Sol-gel method which enables it to be coated with a low temperature treat, applies it to pearlite using Lightweight Aggregate Concrete fixed with a low temperature treat and evaluates the spread performance of it. In addition to this, the size of pearlite is divided into two types: One is 2.5 mm to 5.0 mm and the other is more than 5.0 mm for the benefit of finding out the removal characteristics of $CH_3CHO$ whether they are affected by pearlite size, mixing method and ratio with $TiO_2$ and elapsed time. The result of this experiment shows that although $TiO_2$ produced by Sol-gel method is treated with 120 temperature, it maintains a high spread rate on the XRF(X ray Florescence) quantitative analysis which ranks $TiO_2$ 38 percent, $SiO_2$ 29 percent and CaO 18 percent. In the size of perlite from 2.5 mm to 5.0 mm, the removal characteristic of $CH_3CHO$ from a low temperature heated Lightweight concrete appears 20 percent higher when $TiO_2$ with Sol-gel method is spreaded on the 7 percent of surface. In other words, the removal rate is 94 percent compared with the 72 percent where $TiO_2$ is mixed in 10 percent surface. In more than 5.0 mm sized perlite, the removal rate of $CH_3CHO$, when $TiO_2$ is mixed with 10 percent, is 69 percent, which is similar with that of the previous case. It suggests that the size of pearlite has little effects on the removal rate of $CH_3CHO$. In terms of Elapsed time, the removal characteristic seems apparent at the early stage, where the average removal rate for the first 10 hours takes up 84 percent compared with that of 20 hours.