| Title |
The CH₃CHO Removal Characteristics of Lightweight Aggregate Concrete with TiO₂ Spreaded by Low Temperature Firing using Sol-gel Method |
| Keywords |
sol-gel method;low temperature firing;TiO₂;lightweight aggregate concrete;CH₃CHO;Sol-gel법;저온소성;이산화티탄;경량골재콘크리트;아세트알데히드 |
| Abstract |
Recently studies on functional concrete with a photocatalytic material such as TiO₂ have actively been carried out in order to remove air pollutants. The absorbtion of TiO₂ 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 TiO₂ lise. As a result, the direct coating of TiO₂ on materials" surface is more used for effectiveness. The Surface spread of it needs to have a more than 400℃ 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 TiO₂ 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 ㎜ to 5.0 ㎜ and the other is more than 5.0 ㎜ for the benefit of finding out the removal characteristics of CH₃CHO whether they are affected by pearlite size, mixing method and ratio with TiO₂ and elapsed time. The result of this experiment shows that although TiO₂ 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 TiO₂ 38 percent, SiO₂ 29 percent and CaO 18 percent. In the size of perlite from 2.5 ㎜ to 5.0 ㎜, the removal characteristic of CH₃CHO from a low temperature heated Lightweight concrete appears 20 percent higher when TiO₂ 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 TiO₂ is mixed in 10 percent surface. In more than 5.0 mm sized perlite, the removal rate of CH₃CHO, when TiO₂ 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 CH₃CHO. 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. |