The Effect of the Presence of Mist in the Proposed Sonophotocatalytic Wastewater Treatment Process

Abstract

Advanced oxidation processes (AOPs) involve the generation of highly reactive hydroxyl radicals and can efficiently treat refractory organic compounds in wastewater. Photocatalytic AOPs use photocatalysts that utilize light. The performance of photocatalytic reactions can be limited by the surface area of the catalyst and mass transfer of the contaminants. Sonophotocatalytic processes that involve the combination of sonocatalysis and photocatalysis have been studied for improved pollutant removal. To further improve the process, a sonophotocatalytic process that utilizes the mist particles that are generated via ultrasound is proposed. Some of the features of the mist include its increased surface area and shorter light penetration distance. Using TiO₂ as the photocatalyst and phenol as the representative organic contaminant, the effect of the mist particles on the sonophotocatalytic process was assessed. The results of the experiment demonstrated that the generation of mist particles increased the apparent rate of the removal of phenol by 31.3 %. Additionally, the properties of the TiO₂ catalyst after ultrasound and UV irradiation were investigated. In the future designs of sonophotocatalytic processes, the mist particles may be utilized to improve the removal of refractory organics.