초음파 촉매 공정에서 주파수와 고정된 고체 촉매가 라디칼 생성에 미치는 영향

Abstract

The fixed solid catalysts such as glass bead, steel mesh, and TiO2 coated ceramic bead were used to investigate effect of radical production at different frequencies. The radical production rate at 300 kHz was faster than that at 35 kHz without solid, but the tendency was changed with the presence of glass bead. The presence of glass beads create non-continuous points between the solid and liquid phases leading to increased formation of cavitation bubbles. However, the radical production decreased when steel mesh was used at 35 kHz although the surface area of contact with liquid was same when glass bead was used. Hence the solid catalyst did not always enhance the radical production. The radical production using TiO2 coated ceramic bead was dramatically increased at 35 kHz due to the breakage of TiO2 coated ceramic bead. Therefore the radical productions at 300 kHz using fixed solid catalysts generally increased while at 35 kHz the results fluctuated according to the experimental conditions.