페놀 분해를 위한 오존 나노기포 공정에서 초음파 조사의 영향

초록

In this study, we investigated the ozone nanobubble process in which nanobubble and ultrasonic cavitation were applied simultaneously to improve the dissolution and self-decomposition of ozone. To confirm the organic decomposition efficiency of the process, a 200 mm × 200 mm × 300 mm scale reactor was designed and phenol decomposition experiments were conducted. The use of nanobubble was 2.07 times higher than the conventional ozone aeration in the 60 minutes reaction and effectively improved the dissolution efficiency of ozone. Ultrasonic irradiation increased phenol degradation by 36% with nanobubbles, and dissolved ozone concentration was lowered due to the promotion of ozone self-decomposition. The higher the ultrasonic power was, the higher the phenol degradation efficiency. The decomposition efficiency of phenol was the highest at 132 kHz. The ozone nanobubble process showed better decomposition efficiency at high pH like conventional ozone processes but achieved 100% decomposition of phenol after 60 minutes reaction even at neutral conditions. The effect by pH was less than that of the conventional ozone process because of self-decomposition promotion. To confirm the change in bubble properties by ultrasonic irradiation, a Zetasizer was used to measure the bubbles' size and zeta potential analysis. Ultrasonic irradiation reduced the average size of the bubbles by 11% and strengthened the negative charge of the bubble surface, positively affecting the gas transfer of the ozone nanobubble and the efficiency of the radical production.

키워드