Ultrafine bubbles as an augmenting agent for ozone-based advanced oxidation

Abstract

In this study, the influence of nanobubbles (NBs) application in ozone (O3) based advanced oxidation processes (AOP) is investigated. The results demonstrate the potential of NBs application to O3 – based AOP. It was observed that NBs suppress the negative influence of pH and operating temperatures on the efficiency of ozonation. In addition, the application of NBs tends to improve the solubility of O3 and the rate of mass transfer under the influence of a broad range of temperature and pH conditions. The results of this research indicate that application of NBs minimized the reduction in concentration of dissolved O3 with an increase in temperature. Furthermore, application of NBs highly improved the OH radical formation in acidic conditions. The results of this research depicted for first time that the application of NBs strongly encourages the initiation of reactions involving OH radicals. It was found by this research that NBs can boost the concentration of OH radicals up to 3.5 fold compared to equivalent MB-supported ozonation systems. This is assumed to improve the efficiency of currently existing conventional bubble supported O3 – based AOP systems. HIGHLIGHTS MB nanosizing reduces the negative influence of pH on the efficiency of ozonation.; MB nanosizing reduces the negative influence of temperature on ozonation efficiency.; Nanobubbles enhance ̇OH concentration by up to 3.5 fold compared to microbubbles.; Nanobubbles improve the mass transfer of O3 during ozonation compared to MBs.;

Keywords

• advanced oxidation
• mass transfer
• microbubbles
• nanobubbles
• ozone
• ultrafine bubble