Quantification of hydroxyl radicals in photocatalysis and acoustic cavitation: Utility of coumarin as a chemical probe

• Probe based total OH quantification is unlikely but frequently reported. Uncertainty of make it an unsuitable performance indicator. Fate was deconstructed to identify a suitable utilised by the probe [P] process specific Performance acoustic cavitation and photocatalysis compared on [P]. In-situ hydroxyl radical production characteristic advanced oxidation processes (AOPs) its crucial for assessing these processes. Direct however due their high reactivity short life-time (~10 ?6 s). Therefore, chemical probes (like coumarin) are often used indirectly quantify radicals. The resulting hydroxylated products molecules relatively stable detectable 7-hydroxycoumarin; 7OHC); concentration usually related concentration. Reported literature suggests use constant fraction (6.1%) as yield 7OHC from radicals generated (?). This originally determined ?-irradiation studies coumarin translated across other AOPs. It highly that this same To address gap means comparing AOPs, in present work, we during (AC) (PC) yields. Since ? cannot be directly, alternative simple comparison amount desired reactions i.e., hydroxylation exploited. Based proposed comparison, higher PC than AC ~ 25 times under considered operating conditions. presented results will useful researchers engineers interested quantifying optimising