Abstract
Effluent organic matter (EfOM), a major ozone consumer during wastewater ozonation, is a complex mixture of natural and anthropogenic organic molecules. Ozonation of EfOM adds to molecular complexity by introducing polar and potentially mobile ozonation byproducts (OBPs). Currently, nontargeted direct infusion (DI) ultrahigh resolution mass spectrometry (e.g. FT-ICR-MS) is used to study OBPs but requires sample extraction, limiting the accessible polarity range of OBPs. To better understand the impact of ozonation on EfOM and the formation of polar OBPs, nonextracted effluent was analyzed by direct injection onto a reversed-phase liquid chromatography system (RP-LC) online hyphenated with an FT-ICR-MS. Over four times more OBPs were detected in nonextracted EfOM compared to effluent extracted with solid phase extraction and measured with DI-FT-ICR-MS (13817 vs 3075). Over 1500 highly oxygenated OBPs were detected exclusively in early eluting fractions of nonextracted EfOM, indicating polar OBPs. Oxygenation of these newly discovered OBPs is higher than previously found, with an average molecular DBE-O value of -3.3 and O/C ratio of 0.84 in the earliest eluting OBP fractions. These polar OBPs are consistently lost during extraction but may play an important role in understanding the environmental impact of ozonated EfOM. Moreover, 316 molecular formulas classified as nonreactive to ozone in DI-FT-ICR-MS can be identified with LC-FT-ICR-MS as isomers with varying degrees of reactivity, providing for the first time experimental evidence of differential reactivity of complex organic matter isomers with ozone.
Highlights
Effluent organic matter (EfOM) is a highly complex mixture composed of natural organic matter (NOM), soluble microbial products, organic micropollutants (OMP), and particulate matter.[1]
EfOM is the main consumer of ozone and has been typically considered an interfering substance in the ozonation of OMPs.[12,23−28] Ozonation has been shown to transform hydrophobic fractions of EfOM into more hydrophilic and polar products,[29,30] and recent work to characterize ozonation byproducts (OBPs) from EfOM with mass spectrometric methods found the OBPs from EfOM are more saturated and more oxidized, while the consumed compounds were more condensed and aromatic and less oxidized.[15,31,32]
Utilizing an reversed-phase liquid chromatography system (RP-liquid chromatography (LC)) column directly coupled to a mass spectrometer separates the salts from the EfOM in the original, nonextracted sample, decreasing both ion suppression and discrimination of more polar organic matter, allowing for EfOM analysis without prior extraction (Figures SI 1 and 2)
Summary
Effluent organic matter (EfOM) is a highly complex mixture composed of natural organic matter (NOM), soluble microbial products, organic micropollutants (OMP) (including personal care products and pharmaceuticals), and particulate matter.[1]. OBPs were identified based on DOC normalized mass peak intensities of assigned molecular formulas found between ozonated and nonozonated treatments in the respective segments or DI spectra.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
