Effects of dissolved organic matter characteristics on the photosensitized degradation of pharmaceuticals in wastewater treatment wetlands

Abstract

Wastewater treatment wetlands are aquatic systems where diverse dissolved organic matter (DOM) compositions physically interact. Complex photochemical behaviors ensue, leading to uncertainties in the prediction of indirect photodegradation rates for...

Dissolved Organic Matter Photoreactivity Is Determined by Its Optical Properties, Redox Activity, and Molecular Composition

“…16,25−30 In contrast, Φ • OH has the same trends as other PPRI or E 2 ;E 3 in some studies 24,31,32 but opposite trends in other studies. 17 the same pools of highly aliphatic DOM at the molecular level in several small sets of samples, 14,26,36 and we previously demonstrated that separate pools of DOM are strongly related to f TMP and Φ 1 Od 2 in comparison with Φ • OH . 14 However, these molecular level trends have not yet been tested in diverse waters.…”

“…The predominant quencher of 3 DOM is O 2 , which forms singlet oxygen ( 1 O 2 ) via energy transfer from 3 DOM. Both 3 DOM and 1 O 2 can react to transform some organic contaminants. ,, Autochthonous DOM or DOM originating from wastewater has been shown to be more photoreactive in terms of producing these PPRI. ,, Other PPRI, including hydrogen peroxide (H 2 O 2 ), superoxide, (O 2 •– ), and hydroxyl radical ( • OH), form through electron-transfer reactions, but exact pathways are less well understood. , The two predominant mechanisms discussed in the literature include reduction of O 2 or H-atom abstraction from water . Precursors for these PPRI may include 1 DOM, 3 DOM, charge-transfer species, or other photochemically excited complexes associated with DOM. − …”

“…Conflicting evidence exists about relationships between 3 DOM quantum yield coefficients ( f TMP ) and 1 O 2 quantum yields (Φ 1 O 2 ) as compared to those for Φ • OH , which is likely because 3 DOM and 1 O 2 form via energy transfer and • OH results from electron transfer. ,, For example, f TMP and Φ 1 O 2 are often correlated with each other and with properties derived from UV–vis spectroscopy, such as E 2 :E 3 (i.e., the ratio of absorbance at 250 to 365 nm). ,− In contrast, Φ • OH has the same trends as other PPRI or E 2 ;E 3 in some studies ,, but opposite trends in other studies. ,− 3 DOM and 1 O 2 quantum yields are positively correlated with the same pools of highly aliphatic DOM at the molecular level in several small sets of samples, ,, and we previously demonstrated that separate pools of DOM are strongly related to f TMP and Φ 1 O 2 in comparison with Φ • OH . However, these molecular level trends have not yet been tested in diverse waters.…”

“…7,14,15 Autochthonous DOM or DOM originating from wastewater has been shown to be more photoreactive in terms of producing these PPRI. 14,16,17 Other PPRI, including hydrogen peroxide (H 2 O 2 ), superoxide, (O 2…”

Fast Tracking and Detection of Organic Matter in an Urban Sewage Treatment Plant Using Fluorescence Spectroscopy and UV-Vis Absorption Spectroscopy

“…However, these chemical methods exhibit drawbacks such as long test period, high costs, and significant consumption of chemical reagents, making them difficult to meet the needs of real-time online monitoring. Optical methods provide advantages such as rapid detection, simple operation, and non-destructive sample analysis [7]. In recent years, with the advancement of new technologies such as optical and spectroscopic techniques, notably the emergence of three-dimensional fluorescence spectroscopy and UV-Vis absorption spectroscopy, rapid real-time monitoring of wastewater treatment plants has been rendered feasible [8][9].…”