Figures-of-merit for the technical development and application of advancedoxidation technologies for both electric- and solar-driven systems - (IUPAC Technical Report)

Advanced oxidation technologies (AOTs), which involve the in situ generatio n of highly potent chemical oxidants, such as the hydroxyl radical (. OH). have emerged as an important class of technologies for accelerating the oxi dation land hence removal) of a wide range of organic contaminants in pollu ted water and air. In this report, standard figures-of-merit are proposed f or the comparison and evaluation of these waste treatment technologies. The se figures-of-merit are based on electric-energy consumption (for electric- energy-driven systems) or collector area (for solar-energy-driven systems). They fit within two phenomenological kinetic order regimes: 1)for high con taminant concentrations (electric energy per mass. E-EM or collector area p er mass, A(CM)) and 2) for low concentrations (electric energy per order of magnitude, E-EO, or collector area per order of magnitude, A(CO)). Further more, a simple understanding of the overall kinetic behavior of organic con taminant removal in a waste stream (i.e., whether zero- or first-order) is shown to be necessary for the description of meaningful electric- or solar- energy efficiencies. These standard figures-of-merit provide a direct link to the electric- or solar-energy efficiency (lower values mean higher effic iency) of an advanced oxidation technology, independent of the nature of th e system, and therefore allow for direct comparison of widely disparate AOT s. These figures-of-merit are also shown to be inversely proportional to fu ndamental efficiency factors, such as the lamp efficiency (for electrical s ystems), the fraction of the emitted light that is absorbed in the aqueous solution, and the quantum yield of generation of active radicals.