Improved ultrasonic degradation of hydrophilic and hydrophobic aldehydes in water by combined use of atomization and UV irradiation onto the mist surface.

•Combined ultrasonic and UV254 irradiation promoted degradation of hydrophilic aldehydes.•Hydrophilic aldehydes effectively decomposed on the mist surface in the gas phase.•Ultrasonic atomization suppressed hydroxyl radical scavenging by excess H2O2.•Combined use of UV254 irradiation and H2O2 addition improved the mineralization ratio.