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Urs von Gunten

Cette personne a quitté l’EPFL

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Publications associées (155)

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Toxic effects of substituted p-benzoquinones and hydroquinones in in vitro bioassays are altered by reactions with the cell assay medium

Urs von Gunten, Kristin Schirmer

Substituted para-benzoquinones and hydroquinones are ubiquitous transformation products that arise during oxidative water treatment of phenolic precursors, for example through ozonation or chlorination. The benzoquinone structural motive is associated with ...

PERGAMON-ELSEVIER SCIENCE LTD2021

Photochemical oxidation of phenols and anilines mediated by phenoxyl radicals in aqueous solution

Urs von Gunten, Stephanie Christa Remke

Reactive intermediates formed upon irradiation of chromophoric dissolved organic matter (CDOM) contribute to the degradation of various organic contaminants in surface waters. Besides well-studied "short-lived" photo oxidants, such as triplet state CDOM (3 ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Evaluation of the role of superoxide radical as chain carrier for the formation of hydroxyl radical during ozonation

Urs von Gunten, Gang Yu

Superoxide radicals (O-2(center dot-)) have been suggested as an important chain carrier in the radical chain reaction that promotes ozone (O-3) decomposition to hydroxyl radicals ((OH)-O-center dot) during ozonation. However, due to the difficulty in meas ...

PERGAMON-ELSEVIER SCIENCE LTD2023

Oxidation of 51 micropollutants during drinking water ozonation: Formation of transformation products and their fate during biological post-filtration

Urs von Gunten

Micropollutants (MP) with varying ozone-reactive moieties were spiked to lake water in the influent of a drinking water pilot plant consisting of an ozonation followed by a biological sand filtration. During ozonation, 227 transformation products (OTPs) fr ...

PERGAMON-ELSEVIER SCIENCE LTD2021

Generation of hydroxyl radical during chlorination of hydroxyphenols and natural organic matter extracts

Urs von Gunten, Eva Maria Rodriguez Franco

The generation of hydroxyl radicals ((OH)-O-center dot) during the chlorination of air saturated solutions of different hydroxyphenols (hydroquinone, resorcinol, catechol, gallic and tannic acids) at pH 7 has been determined by the formation of phenol (in ...

2020

Oxidation processes and me

Urs von Gunten

This publication summarizes my journey in the field of chemical oxidation processes for water treatment over the last 30+ years. Initially, the efficiency of the application of chemical oxidants for micropollutant abatement was assessed by the abatement of ...

Pergamon-Elsevier Science Ltd2024

Column studies to assess the effects of climate variables on redox processes during riverbank filtration

Urs von Gunten, Janet Gordon Hering

Riverbank filtration is an established technique used world-wide to produce clean drinking water in a reliable and cost-efficient way. This practice is, however, facing new challenges posed by climate change, as already observed during past heat waves with ...

Elsevier2014

Development of prediction models for the reactivity of organic compounds with ozone in aqueous solution by quantum chemical calculations: Role of delocalized and localized molecular orbitals

Urs von Gunten, Jeremy Samuel Arey, Minju Lee, Saskia Gisela Zimmermann-Steffens

Second-order rate constants (k(O3)) for the reaction of ozone with micropollutants are essential parameters for the assessment of micropollutant elimination efficiency during ozonation in water and wastewater treatment. Prediction models for k(O3) were dev ...

Amer Chemical Soc2015

Reaction of bromine and chlorine with phenolic compounds and natural organic matter extracts - Electrophilic aromatic substitution and oxidation

Urs von Gunten, Eva Maria Rodriguez Franco

Phenolic compounds are known structural moieties of natural organic matter (NOM), and their reactivity is a key parameter for understanding the reactivity of NOM and the disinfection by-product formation during oxidative water treatment. In this study, spe ...

Elsevier2015

Nanoplastics removal during drinking water treatment: Laboratory- and pilot-scale experiments and modeling

Urs von Gunten

Microplastics detected in potable water sources and tap water have led to concerns about the efficacy of current drinking water treatment processes to remove these contaminants. It is hypothesized that drinking water resources contain nanoplastics (NPs), b ...

ELSEVIER2022

Surface water treatment by UV/H2O2 with subsequent soil aquifer treatment: impact on micropollutants, dissolved organic matter and biological activity

Urs von Gunten

Because organic micropollutants (MP) are frequently detected in river waters that are used as drinking water sources, combining a relatively cost-efficient natural treatment with upstream advanced oxidation processes (AOP) appears promising for their effic ...

ROYAL SOC CHEMISTRY2019

Formation of transformation products during ozonation of secondary wastewater effluent and their fate in post-treatment: From laboratory-to full-scale

Urs von Gunten

Ozonation is increasingly applied in water and wastewater treatment for the abatement of micropollutants (MPs). However, the transformation products formed during ozonation (OTPs) and their fate in biological or sorptive post-treatments is largely unknown. ...

PERGAMON-ELSEVIER SCIENCE LTD2021

Mixture effects of drinking water disinfection by-products: implications for risk assessment

Urs von Gunten

Disinfection by-products (DBPs) in drinking water have been associated with increased cancer risk but single DBPs cannot explain epidemiological cancer occurrences. To test if combined effects of DBPs are plausible to explain epidemiological evidence for a ...

ROYAL SOC CHEMISTRY2020

Kinetics of the reaction between hydrogen peroxide and aqueous iodine: Implications for technical and natural aquatic systems

Urs von Gunten, Jaedon Shin

Oxidative treatment of iodide-containing waters can lead to a formation of potentially toxic iodinated disinfection byproducts (I-DBPs). Iodide (I-) is easily oxidized to HOI by various oxidation processes and its reaction with dissolved organic matter (DO ...

2020

Efficiency and energy requirements for the transformation of organic micropollutants by ozone, O3/H2O2 and UV/H2O2

Urs von Gunten

The energy consumptions of conventional ozonation and the AOPs O3/H2O2 and UV/H2O2 for transformation of organic micropollutants, namely atrazine (ATR), sulfamethoxazole (SMX) and N-nitrosodimethylamine (NDMA) were compared. Three lake waters and a wastewa ...

Elsevier2011

Kinetic and mechanistic understanding of chlorite oxidation during chlorination: Optimization of ClO2 pre-oxidation for disinfection byproduct control

Urs von Gunten

Chlorine dioxide (ClO2) applications to drinking water are limited by the formation of chlorite (ClO2-) which is regulated in many countries. However, when ClO2 is used as a pre-oxidant, ClO2- can be oxidized by chlorine during subsequent disinfection. In ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Enhanced transformation of sulfonamide antibiotics by manganese(IV) oxide in the presence of model humic constituents

Urs von Gunten, Jun Ma, Jin Jiang

In this study, a manganese(IV) oxide-mediator (MnO2-mediator) system for the abatement of sulfonamide antibiotics was evaluated. Two simple model humic constituents, syringaldehyde (SA) and acetosyringone (AS), could promote the transformation of sulfonami ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Reactions of alpha,beta-Unsaturated Carbonyls with Free Chlorine, Free Bromine, and Combined Chlorine

Urs von Gunten

Chemical disinfectants employed in water and wastewater treatment can produce a variety of transformation products, including carbonyl compounds (e.g., saturated and unsaturated aldehydes and ketones). Experiments conducted under conditions relevant to chl ...

AMER CHEMICAL SOC2021

Unveiling the reaction chemistry of sulfoxides during water chlorination

Urs von Gunten

Species-specific second-order rate constants for the reactions of eight model sulfoxides with hypochlorous acid (k(HOCl)) were determined to be in the range of 2.7 M-1 s(-1) to 5.8 x 10(3) M-1 s(-1). A quantitative structure-activity relationships (QSAR) w ...

PERGAMON-ELSEVIER SCIENCE LTD2025

Chlorination of bromide-containing waters: Enhanced bromate formation in the presence of synthetic metal oxides and deposits formed in drinking water distribution systems

Urs von Gunten, Chao Liu

Bromate formation from the reaction between chlorine and bromide in homogeneous solution is a slow process. The present study investigated metal oxides enhanced bromate formation during chlorination of bromide-containing waters. Selected metal oxides enhan ...

Elsevier2013