Publications by Urs von Gunten

Characterization of Organic Nitrogen by Chlorination, Ozonation, and Stable Isotope Analysis of Nitrate

During oxidation, nitrogenous species in dissolved organic matter (DOM) are critical in the formation of nitrogenous, potentially toxic disinfection byproducts, but their chemical identity remains poorly understood. Here, we developed three complementary a ...

American Chemical Society (ACS)2025

Enhanced abatement of phenolic compounds by chlorine in the presence of CuO: Absence of electrophilic aromatic substitution

Urs von Gunten

It has been demonstrated that chlorine predominately reacts with phenolic compounds through an electrophilic aromatic substitution, yielding chlorinated phenols. Previous studies showed that copper oxide (CuO), a water pipe corrosion product, can catalytic ...

PERGAMON-ELSEVIER SCIENCE LTD2025

Effect of surfactants on inactivation of Bacillus subtilis spores by chlorine

Sandor Kasas, Urs von Gunten, María Inés Villalba, Tianqi Zhang

Bacterial spores pose significant risks to human health, yet the inactivation of spores is challenging due to their unique structures and chemical compositions. This study investigated the synergistic effect between surfactants and chlorine on the inactiva ...

2025

Ozonation of wastewater effluent by the MEMBRO3X contactor: Micropollutants abatement and bromate mitigation

Urs von Gunten, Jaedon Shin

Wastewater treatment plants (WWTPs) are significant sources of micropollutants, potentially adversely affecting freshwater ecosystems. Ozonation is an effective way to abate micropollutants during treatment of wastewater effluent, however, the presence of ...

2025

Reactions of N,O- and N,S-Azoles and -Azolines with Ozone: Kinetics and Mechanisms

Urs von Gunten

N,O- and N,S-azoles and -azolines are common functional groups in pharmaceuticals, agrochemicals and natural products. Their fate during ozone-based water treatment processes is unknown due to a lack of kinetic and mechanistic information on their reaction ...

American Chemical Society (ACS)2025

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

Reactions of hypobromous acid with dimethyl selenide, dimethyl diselenide and other organic selenium compounds: kinetics and product formation

Urs von Gunten

Selenium (Se) is an essential micronutrient for many living organisms particularly due to its unique redox properties. We recently found that the sulfur (S) analog for dimethyl selenide (DMSe), i.e. dimethyl sulfide (DMS), reacts fast with the marine oxida ...

Royal Soc Chemistry2024

Role of Carbonyl Compounds for N-Nitrosamine Formation during Nitrosation: Kinetics and Mechanisms

Florian Frédéric Vincent Breider, Urs von Gunten, Yishuai Pan

N-Nitrosamines are potential human carcinogens frequently detected in natural and engineered aquatic systems. This study sheds light on the role of carbonyl compounds in the formation of N-nitrosamines by nitrosation of five secondary amines via different ...

2024

Achieving realistic ozonation conditions with synthetic water matrices comprising low-molecular-weight scavenger compounds

Urs von Gunten

Ozonation is used worldwide for drinking water disinfection and increasingly also for micropollutant abatement from wastewater. Identification of transformation products formed during the ozonation of micropollutants is challenging due to several factors i ...

PERGAMON-ELSEVIER SCIENCE LTD2024

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

Reactivity of Cyanobacteria Metabolites with Ozone: Multicompound Competition Kinetics

Urs von Gunten

Cyanobacterial blooms occur at increasing frequency and intensity, notably in freshwater. This leads to the introduction of complex mixtures of their products, i.e., cyano-metabolites, to drinking water treatment plants. To assess the fate of cyano-metabol ...

Amer Chemical Soc2024

The Mn(VII)-H2O2 oxidation process: Abatement of electron-deficient N-containing organic compounds

Urs von Gunten, Ke Xu

Chemical oxidants applied in water treatment are electrophiles, which preferentially attack sites with higher electron density. This typically results in less efficient oxidative abatement of organic compounds with electronwithdrawing substituents. In this ...

Elsevier Science Sa2024

Ozonation of lake water and wastewater: Identification of carbonous and nitrogenous carbonyl-containing oxidation byproducts by non-target screening

Urs von Gunten, Joanna Maria Houska

Ozonation of drinking water and wastewater is accompanied by the formation of 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 develope ...

PERGAMON-ELSEVIER SCIENCE LTD2023

Chlorination of amides: Kinetics and mechanisms of formation of N-chloramides and their reactions with phenolic compounds

Urs von Gunten, Tianqi Zhang

Amides are common constituents in natural organic matter and synthetic chemicals. In this study, we investi-gated kinetics and mechanisms of the reactions of chlorine with seven amides, including acetamide, N-meth-ylformamide, N-methylacetamide, benzamide, ...

2023

Predicting Transformation Products during Aqueous Oxidation Processes: Current State and Outlook

Urs von Gunten

Water quality and its impacts on human and ecosystem health presents tremendous global challenges. While oxidative water treatment can solve many of these problems related to hygiene and micropollutants, identifying and predicting transformation products f ...

2023

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

Gang Yu, Urs von Gunten, Yan Wang

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

Impact of chlorination and ozonation of dissolved organic matter on its photo-induced production of long-lived photooxidants and excited triplet states

Silvio Canonica, Urs von Gunten, Stephanie Christa Remke, Joanna Maria Houska

Recent studies suggested that long-lived photooxidants (LLPO), which are reactive intermediates formed during irradiation of dissolved organic matter (DOM), may consist of phenoxyl radicals derived from phenolic moieties of the DOM. Besides the well-studie ...

PERGAMON-ELSEVIER SCIENCE LTD2023

Hydrogen Peroxide Formation during Ozonation of Olefins and Phenol: Mechanistic Insights from Oxygen Isotope Signatures

Urs von Gunten, Joanna Maria Houska

Mitigation of undesired byproducts from ozonation of dissolved organic matter (DOM) such as aldehydes and ketones is currently hampered by limited knowledge of their precursors and formation pathways. Here, the stable oxygen isotope composition of H2O2 for ...

AMER CHEMICAL SOC2023

Oxidative Water Treatment: The Track Ahead

Urs von Gunten, Yun Ho Lee

Chemical oxidation has been applied in municipal water treatment for more than a century, initially for disinfection. In the early decades, chlorine disinfection was adopted in the fight against waterborne disease. However, the oxidative properties of chlo ...

2023

Formation of carbonyl compounds during ozonation of lake water and wastewater: Development of a non-target screening method and quantification of target compounds

Urs von Gunten, Joanna Maria Houska

Ozonation of natural waters is typically associated with the formation of carbonyl compounds (aldehydes, ketones and ketoacids), a main class of organic disinfection byproducts (DBPs). However, the detection of carbonyl compounds in water and wastewater is ...

PERGAMON-ELSEVIER SCIENCE LTD2023