Détail de l'archive

L’oxydation, mais de manière maîtrisée - une thèse primée

17 juillet 2024 | Andri Bryner

La chimiste de l’environnement Joanna Houska a été récompensée pour sa thèse de doctorat par la Deutsche Wasserchemische Gesellschaft (Société allemande de Chimie de l’Eau). Joanna Houska a mené des recherches à l’Eawag et à l’EPFL, et a démontré tant théoriquement qu’expérimentalement comment le traitement oxydatif de l’eau avec de l’ozone ou du chlore peut être utilisé de manière plus efficace lorsqu’on connaît plus précisément les substances organiques dissoutes dans l’eau à traiter

«Ce travail est un jalon vers une meilleure compréhension du rôle de la matière organique dissoute dans le traitement oxydatif de l’eau», déclare Urs von Gunten, le directeur de thèse de Joanna Houska. Il est professeur à l’EPFL et dirige à l’Institut de recherche de l’eau Eawag le groupe Chimie de l’eau potable. Selon von Gunten, Joanna Houska possède «une énorme capacité à traiter des questions scientifiques complexes de manière théorique et expérimentale et à résoudre des problèmes avec une grande indépendance.» Dans ses expériences, mais aussi grâce à la modélisation, la chercheuse a produit et interprété de nouvelles données passionnantes qui peuvent être utilisées pour améliorer le traitement oxydatif de l’eau.

Inefficace et dangereux sans analyse précise

Quel est donc le problème? Lorsqu’on utilise du chlore ou de l’ozone pour la désinfection/l’oxydation de l’eau, le principal objectif est de neutraliser les germes pathogènes et les micropolluants. Mais la majeure partie des agents oxydants réagit avec les composants de la matrice de l’eau, tels que la matière organique dissoute. Cela réduit non seulement l’efficacité des procédés, mais peut aussi, dans le pire des cas, entraîner la formation de sous-produits toxiques. Il est donc important de savoir le plus précisément possible ce qui est dissous dans l’eau à traiter afin de rendre l’oxydation efficace. C’est là que la chercheuse Joanna Houska est intervenue, car jusqu’à présent, on utilisait principalement des paramètres globaux dérivés, par exemple, de l’absorption UV. Dans sa thèse, elle a donc tout d’abord développé des méthodes destinées à mesurer la concentration de composés pertinents. Elle les a ensuite caractérisés et a évalué s’ils pouvaient former des sous-produits problématiques, et dans quelle mesure. Enfin, elle a découvert, grâce aux isotopes de l’oxygène dans le peroxyde d’hydrogène, comment les précurseurs sensibles peuvent être distingués les uns des autres. Il est en outre intéressant de noter que Joanna Houska n’a pas limité sa recherche uniquement à la désinfection/l’oxydation de l’eau destinée à être utilisée comme eau potable. Bien plus, elle a également suivi, dans une station d’épuration, la formation de sous-produits de l’ozonation et leur dégradation ultérieure lors du traitement biologique secondaire des eaux usées épurées.

Pour la première fois en Suisse

Le Promotionspreis (en français: prix de thèse) dans le domaine de la chimie de l’eau est décerné depuis 1992 et est doté de 1500 euros. En 2024, il va pour la première fois à la Suisse. Joanna Houska sait déjà ce qu’elle fera de cet argent: «Mon vélo a besoin d’une mise à niveau urgente, donc l’argent du prix sera probablement investi là-dedans». Elle travaille désormais dans le département Environnement de Roche, dans le domaine des eaux usées et de la protection des eaux.
 

Photo de couverture: Joanna Houska lors de la remise du prix avec le Prof. Thomas Ternes au congrès annuel de la Wasserchemische Gesellschaft à Limburg (D) (Photo: Nina Hermes, BfG).
 

Publication originale

Extbase Variable Dump
array(3 items)
   publications => '23921,30070,30998,30345' (23 chars)
   libraryUrl => '' (0 chars)
   layout => '0' (1 chars)
Extbase Variable Dump
array(4 items)
   0 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=23921, pid=124)
      originalId => protected23921 (integer)
      authors => protected'Houska, J.; Salhi, E.; Walpen, N.; von Gunten, U.' (69 chars)
      title => protected'Oxidant-reactive carbonous moieties in dissolved organic matter: selective q
         uantification by oxidative titration using chlorine dioxide and ozone
' (145 chars) journal => protected'Water Research' (14 chars) year => protected2021 (integer) volume => protected207 (integer) issue => protected'' (0 chars) startpage => protected'117790 (11 pp.)' (15 chars) otherpage => protected'' (0 chars) categories => protected'dissolved organic matter; oxidative titration; chlorine dioxide; ozone; elec
         tron-donating capacity; molecular tagging; electron-rich moieties; phenols;
         oxidation byproducts
' (172 chars) description => protected'The application of oxidants for disinfection or micropollutant abatement dur
         ing drinking water and wastewater treatment is accompanied by oxidation of m
         atrix components such as dissolved organic matter (DOM). To improve predicti
         ons of the efficiency of oxidation processes and the formation of oxidation
         products, methods to determine concentrations of oxidant-reactive phenolic,
         olefinic or amine-type DOM moieties are critical.<br />Here, a novel selecti
         ve oxidative titration approach is presented, which is based on reaction kin
         etics of oxidation reactions towards certain DOM moieties. Phenolic moieties
          were determined by oxidative titration with ClO<sub>2</sub> and O<sub>3</su
         b> for five DOM isolates and two secondary wastewater effluent samples. The
         determined concentrations of phenolic moieties correlated with the electron-
         donating capacity (EDC) and the formation of inorganic ClO<sub>2</sub>-bypro
         ducts (HOCl, ClO<sub>2</sub><sup>−</sup>, ClO<sub>3</sub><sup>−</sup>).
         ClO<sub>2</sub>-byproduct yields from phenol and DOM isolates and changes du
         e to the application of molecular tagging for phenols revealed a better unde
         rstanding of oxidant-reactive structures within DOM.<br />Overall, oxidative
          titrations with ClO<sub>2</sub> and O<sub>3</sub> provide a novel and promi
         sing tool to quantify oxidant-reactive moieties in complex mixtures such as
         DOM and can be expanded to other matrices or oxidants.
' (1422 chars) serialnumber => protected'0043-1354' (9 chars) doi => protected'10.1016/j.watres.2021.117790' (28 chars) uid => protected23921 (integer) _localizedUid => protected23921 (integer)modified _languageUid => protectedNULL _versionedUid => protected23921 (integer)modified pid => protected124 (integer)
1 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=30070, pid=124) originalId => protected30070 (integer) authors => protected'Houska,&nbsp;J.; Manasfi,&nbsp;T.; Gebhardt,&nbsp;I.; von Gunten,&nbsp;U.' (73 chars) title => protected'Ozonation of lake water and wastewater: identification of carbonous and nitr
         ogenous carbonyl-containing oxidation byproducts by non-target screening
' (148 chars) journal => protected'Water Research' (14 chars) year => protected2023 (integer) volume => protected232 (integer) issue => protected'' (0 chars) startpage => protected'119484 (17 pp.)' (15 chars) otherpage => protected'' (0 chars) categories => protected'high resolution mass spectrometry; ozonation; carbonyl compounds; dissolved
         organic matter; lake water; wastewater; phenols
' (123 chars) description => protected'Ozonation of drinking water and wastewater is accompanied by the formation o
         f disinfection byproducts (DBPs) such as low molecular weight aldehydes and
         ketones from the reactions of ozone with dissolved organic matter (DOM). By
         applying a recently developed non-target workflow, 178 carbonous and nitroge
         nous carbonyl compounds were detected during bench-scale ozonation of two la
         ke waters and three secondary wastewater effluent samples and full-scale ozo
         nation of secondary treated wastewater effluent. An overlapping subset of ca
         rbonyl compounds (20%) was detected in all water types. Moreover, wastewater
          effluents showed a significantly higher fraction of <em>N</em>-containing c
         arbonyl compounds (30%) compared to lake water (17%). All carbonyl compounds
          can be classified in 5 main formation trends as a function of increasing sp
         ecific ozone doses. Formation trends upon ozonation and comparison of result
         s in presence and absence of the <sup>•</sup>OH radical scavenger DMSO in
         combination with kinetic and mechanistic information allowed to elucidate po
         tential carbonyl structures. A link between the detected carbonyl compounds
         and their precursors was established by ozonating six model compounds (pheno
         l, 4-ethylphenol, 4-methoxyphenol, sorbic acid, 3-buten-2-ol and acetylaceto
         ne). About one third of the detected carbonous carbonyl compounds detected i
         n real waters was also detected by ozonating model compounds.<br />Evaluatio
         n of the non-target analysis data revealed the identity of 15 carbonyl compo
         unds, including hydroxylated aldehydes and ketones (e.g. hydroxyacetone, con
         fidence level (CL) = 1), unsaturated dicarbonyls (e.g. acrolein, CL = 1;
          2-butene-1,4-dial, CL = 1; 4-oxobut-2-enoic acid, CL = 2) and also a ni
         trogen-containing carbonyl compound (2-oxo-propanamide, CL =1).<br />Overall
         , this study shows the formation of versatile carbonous and nitrogenous carb
         onyl compounds upon ozonation involving ozone and <sup>•</sup>OH reactions
         . Carbonyl compounds wit...
' (2196 chars) serialnumber => protected'0043-1354' (9 chars) doi => protected'10.1016/j.watres.2022.119484' (28 chars) uid => protected30070 (integer) _localizedUid => protected30070 (integer)modified _languageUid => protectedNULL _versionedUid => protected30070 (integer)modified pid => protected124 (integer)
2 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=30998, pid=124) originalId => protected30998 (integer) authors => protected'Houska,&nbsp;J.; Stocco,&nbsp;L.; Hofstetter,&nbsp;T.&nbsp;B.; Gunten,&nbsp;
         U.&nbsp;von
' (87 chars) title => protected'Hydrogen peroxide formation during ozonation of olefins and phenol: mechanis
         tic insights from oxygen isotope signatures
' (119 chars) journal => protected'Environmental Science and Technology' (36 chars) year => protected2023 (integer) volume => protected57 (integer) issue => protected'' (0 chars) startpage => protected'18950' (5 chars) otherpage => protected'18959' (5 chars) categories => protected'ozonation; hydrogen peroxide; reaction mechanisms; olefins; phenol; oxygen i
         sotopes; isotope ratio mass spectrometry
' (116 chars) description => protected'Mitigation of undesired byproducts from ozonation of dissolved organic matte
         r (DOM) such as aldehydes and ketones is currently hampered by limited knowl
         edge of their precursors and formation pathways. Here, the stable oxygen iso
         tope composition of H<sub>2</sub>O<sub>2</sub> formed simultaneously with th
         ese byproducts was studied to determine if it can reveal this missing inform
         ation. A newly developed procedure, which quantitatively transforms H<sub>2<
         /sub>O<sub>2</sub> to O<sub>2</sub> for subsequent <sup>18</sup>O/<sup>16</s
         up>O ratio analysis, was used to determine the δ<sup>18</sup>O of H<sub>2</
         sub>O<sub>2</sub> generated from ozonated model compounds (olefins and pheno
         l, pH 3-8). A constant enrichment of <sup>18</sup>O in H<sub>2</sub>O<sub>2<
         /sub> with a δ<sup>18</sup>O value of ∼59‰ implies that <sup>16</sup>O-
         <sup>16</sup>O bonds are cleaved preferentially in the intermediate Criegee
         ozonide, which is commonly formed from olefins. H<sub>2</sub>O<sub>2</sub> f
         rom the ozonation of acrylic acid and phenol at pH 7 resulted in lower <sup>
         18</sup>O enrichment (δ<sup>18</sup>O = 47-49‰). For acrylic acid, enhanc
         ement of one of the two pathways followed by a carbonyl-H<sub>2</sub>O<sub>2
         </sub> equilibrium was responsible for the smaller δ<sup>18</sup>O of H<sub
         >2</sub>O<sub>2</sub>. During phenol ozonation at pH 7, various competing re
         actions leading to H<sub>2</sub>O<sub>2</sub> via an intermediate ozone addu
         ct are hypothesized to cause lower δ<sup>18</sup>O in H<sub>2</sub>O<sub>2<
         /sub>. These insights provide a first step toward supporting pH-dependent H<
         sub>2</sub>O<sub>2</sub> precursor elucidation in DOM.
' (1650 chars) serialnumber => protected'0013-936X' (9 chars) doi => protected'10.1021/acs.est.3c00788' (23 chars) uid => protected30998 (integer) _localizedUid => protected30998 (integer)modified _languageUid => protectedNULL _versionedUid => protected30998 (integer)modified pid => protected124 (integer)
3 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=30345, pid=124) originalId => protected30345 (integer) authors => protected'Manasfi,&nbsp;T.; Houska,&nbsp;J.; Gebhardt,&nbsp;I.; von Gunten,&nbsp;U.' (73 chars) title => protected'Formation of carbonyl compounds during ozonation of lake water and wastewate
         r: development of a non-target screening method and quantification of target
          compounds
' (162 chars) journal => protected'Water Research' (14 chars) year => protected2023 (integer) volume => protected237 (integer) issue => protected'' (0 chars) startpage => protected'119751 (14 pp.)' (15 chars) otherpage => protected'' (0 chars) categories => protected'carbonyl compounds; disinfection byproducts; ozonation; dissolved organic ma
         tter; non-target analysis; high-resolution mass spectrometry
' (136 chars) description => protected'Ozonation of natural waters is typically associated with the formation of ca
         rbonyl compounds (aldehydes, ketones and ketoacids), a main class of organic
          disinfection byproducts (DBPs). However, the detection of carbonyl compound
         s in water and wastewater is challenged by multiple difficulties inherent to
          their physicochemical properties. A non-target screening method involving t
         he derivatisation of carbonyl compounds with <em>p</em>-toluenesulfonylhydra
         zine (TSH) followed by their analysis using liquid chromatography coupled to
          electrospray ionisation high-resolution mass spectrometry (LC-ESI-HRMS) and
          an advanced non-target screening and data processing workflow was developed
         . The workflow was applied to investigate the formation of carbonyl compound
         s during ozonation of different water types including lake water, aqueous so
         lutions containing Suwannee River Fulvic acid (SRFA), and wastewater. A high
         er sensitivity for most target carbonyl compounds was achieved compared to p
         revious derivatisation methods. Moreover, the method allowed the identificat
         ion of known and unknown carbonyl compounds. 8 out of 17 target carbonyl com
         pounds were consistently detected above limits of quantification (LOQs) in m
         ost ozonated samples. Generally, the concentrations of the 8 detected target
          compounds decreased in the order: formaldehyde &gt; acetaldehyde &gt; glyox
         ylic acid &gt; pyruvic acid &gt; glutaraldehyde &gt; 2,3-butanedione &gt; gl
         yoxal &gt; 1-acetyl-1-cyclohexene. The DOC concentration-normalised formatio
         n of carbonyl compounds during ozonation was higher in wastewater and SRFA-c
         ontaining water than in lake water. The specific ozone doses and the type of
          the dissolved organic matter (DOM) played a predominant role for the extent
          of formation of carbonyl compounds. Five formation trends were distinguishe
         d for different carbonyl compounds. Some compounds were produced continuousl
         y upon ozonation even at high ozone doses, while others reached a maximum co
         ncentration at a certain...
' (2551 chars) serialnumber => protected'0043-1354' (9 chars) doi => protected'10.1016/j.watres.2023.119751' (28 chars) uid => protected30345 (integer) _localizedUid => protected30345 (integer)modified _languageUid => protectedNULL _versionedUid => protected30345 (integer)modified pid => protected124 (integer)
Houska, J.; Salhi, E.; Walpen, N.; von Gunten, U. (2021) Oxidant-reactive carbonous moieties in dissolved organic matter: selective quantification by oxidative titration using chlorine dioxide and ozone, Water Research, 207, 117790 (11 pp.), doi:10.1016/j.watres.2021.117790, Institutional Repository
Houska, J.; Manasfi, T.; Gebhardt, I.; von Gunten, U. (2023) Ozonation of lake water and wastewater: identification of carbonous and nitrogenous carbonyl-containing oxidation byproducts by non-target screening, Water Research, 232, 119484 (17 pp.), doi:10.1016/j.watres.2022.119484, Institutional Repository
Houska, J.; Stocco, L.; Hofstetter, T. B.; Gunten, U. von (2023) Hydrogen peroxide formation during ozonation of olefins and phenol: mechanistic insights from oxygen isotope signatures, Environmental Science and Technology, 57, 18950-18959, doi:10.1021/acs.est.3c00788, Institutional Repository
Manasfi, T.; Houska, J.; Gebhardt, I.; von Gunten, U. (2023) Formation of carbonyl compounds during ozonation of lake water and wastewater: development of a non-target screening method and quantification of target compounds, Water Research, 237, 119751 (14 pp.), doi:10.1016/j.watres.2023.119751, Institutional Repository