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

TLDR

Advanced oxidation technologies generate potent oxidants such as hydroxyl radicals to accelerate removal of diverse organic contaminants from polluted water and air. This report proposes standard figures‑of‑merit for comparing and evaluating these waste‑treatment technologies. The figures‑of‑merit are defined in terms of electric‑energy consumption or collector area and apply to two kinetic regimes—high‑concentration (energy or area per mass) and low‑concentration (energy or area per order of magnitude). They link energy or area usage to efficiency, require understanding of contaminant‑removal kinetics, and are inversely proportional to lamp efficiency, light absorption fraction, and radical quantum yield, enabling direct comparison across diverse AOTs.

Abstract

Abstract Advanced oxidation technologies (AOTs), which involve the in situ generation of highly potent chemical oxidants, such as the hydroxyl radical (áOH), have emerged as an important class of technologies for accelerating the oxidation (and hence removal) of a wide range of organic contaminants in polluted water and air. In this report, standard figures-of-merit are proposed for the comparison and evaluation of these waste treatment technologies. These 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 contaminant concentrations (electric energy per mass, E EM , or collector area per 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 ). Furthermore, a simple understanding of the overall kinetic behavior of organic contaminant 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 efficiency) of an advanced oxidation technology, independent of the nature of the system, and therefore allow for direct comparison of widely disparate AOTs. These figures-of-merit are also shown to be inversely proportional to fundamental efficiency factors, such as the lamp efficiency (for electrical systems), the fraction of the emitted light that is absorbed in the aqueous solution, and the quantum yield of generation of active radicals.