Publications related to Hydroxyl radical

Charge-Transfer States in Organic Nanowires

Charge separation processes in organic semiconductors play a pivotal role in diverse applications ranging from photovoltaics to photocatalysis. Understanding these mechanisms, particularly the role of hybrid charge-transfer (CT) states, is essential for ad ...

EPFL2024

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

Atmospheric isoprene measurements reveal larger-than-expected Southern Ocean emissions

Julia Schmale, Andrea Baccarini

Isoprene is a key trace component of the atmosphere emitted by vegetation and other organisms. It is highly reactive and can impact atmospheric composition and climate by affecting the greenhouse gases ozone and methane and secondary organic aerosol format ...

Nature Research2024

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

Urs von Gunten, Gang Yu, 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

Critical Review on Bromate Formation during Ozonation and Control Options for Its Minimization

Urs von Gunten

Ozone is a commonly applied disinfectant and oxidantin drinkingwater and has more recently been implemented for enhanced municipalwastewater treatment for potable reuse and ecosystem protection. Onedrawback is the potential formation of bromate, a possible ...

AMER CHEMICAL SOC2023

Bacterial inactivation in sunlit surface waters is dominated by reactive species that emanate from the synergy between light, iron, and natural organic matter

César Pulgarin, Stefanos Giannakis, Jun Ma, Da Wang, Shuang Song

In this study, the synergistic and antagonistic effects of Fe species and coexisting natural organic matter (NOM) on the efficacy of solar light disinfection of water are investigated. Different initial iron species (Fe2+/Fe3+) and naturalorganic matter ty ...

Elsevier2023

Influence of aerosol acidity and organic ligands on transition metal solubility and oxidative potential of fine particulate matter in urban environments

Athanasios Nenes, Gerhard Lammel

The adverse health effects of air pollution around the world have been associated with the inhalation of fine particulate matter (PM2.5). Such outcomes are thought to be related to the induction of oxidative stress due to the excess formation of reactive o ...

Elsevier2023

Widespread detection of chlorine oxyacids in the Arctic atmosphere

Julia Schmale, Ivo Fabio Beck, Hélène Paule Angot

Observations are reported of HClO3 and HClO4 in the atmosphere and their widespread occurrence over the pan-Arctic during spring, providing further insights into atmospheric chlorine cycling in the polar environment. ...

Nature Portfolio2023

Optical properties and photochemical production of hydroxyl radical and singlet oxygen after ozonation of dissolved organic matter

Urs von Gunten, Frank Jonathan Leresche

This study focuses on the effects of ozonation on the optical and photochemical properties of dissolved organic matter (DOM). Upon ozonation, a decrease in light absorption properties of DOM was observed concomitantly with a large increase in singlet oxyge ...

ROYAL SOC CHEMISTRY2021

Nighttime chemistry of biomass burning emissions in urban areas: A dual mobile chamber study

Athanasios Nenes, Spyros Pandis

Residential biomass burning for heating purposes is an important source of air pollutants during winter. Here we test the hypothesis that significant secondary organic aerosol production can take place even during winter nights through oxidation of the emi ...

Copernicus GmbH2021

Resonant Inelastic X-ray Scattering Studies of Low-Dimensional and Frustrated 3d Transition-Metal Oxides

Yi Tseng

3d transition-metal oxide materials with strong electron correlations and low dimensionality give rise to emerging exotic phases. Resonant inelastic X-ray scattering (RIXS) has developed as a powerful spectroscopic tool for probing the collective excitatio ...

EPFL2021

Phototransformation of Organic Contaminants in Aquatic Systems: Characterization of Long-Lived Photooxidants Derived from Dissolved Organic Matter

Stephanie Christa Remke

The increasing interest in the fate of organic contaminants in the aquatic environment requires the elucidation of relevant abiotic transformation processes. These processes often involve the ubiquitous dissolved organic matter (DOM), a complex mixture of ...

EPFL2021

Copper-catalyzed transformations of carboradicals generated by electrochemical and photochemical methods: oxidative amination and polyfluoroarylation

Xiangli Yi

Organic radicals are highly active species that can undergo various transformations. Electrochemistry and photochemistry are efficient methods for the generation of these species of high energy, through single electron transfer processes under mild conditi ...

EPFL2021

Aqueous-phase reactive species formed by fine particulate matter from remote forests and polluted urban air

Andrea Mario Arangio, Ting Zhang, Jing Li

In the aqueous phase, fine particulate matter can form reactive species (RS) that influence the aging, properties, and health effects of atmospheric aerosols. In this study, we explore the RS yields of aerosol samples from a remote forest (Hyytiala, Finlan ...

Copernicus Publications2021

New Strategies for the Functionalization of Alkenes Exploiting Tethering Chemistry and Ring Strain

Bastian Antoine Rodolphe Claude Muriel

Amino alcohols, cyclopropanes and nitriles are privileged structural motifs found in the scaffold of natural products and bioactive compounds. In addition, they are versatile building blocks in organic chemistry. The development of new and increasingly eff ...

EPFL2021

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

Molecular-Level Transformation of Dissolved Organic Matter during Oxidation by Ozone and Hydroxyl Radical

Urs von Gunten

Ozonation of drinking and wastewater relies on ozone (O-3) and hydroxyl radical ((OH)-O-center dot) as oxidants. Both oxidants react with dissolved organic matter (DOM) and alter its composition, but the selectivity of the two oxidants and mechanisms of re ...

AMER CHEMICAL SOC2020

The Metal Catalyst Influences the Kinetics and Mechanisms of MS2 Inactivation in Fenton-like Systems

Tamar Kohn, Jessica Ivana Nieto Juarez

Human enteric viruses are frequent microbial contaminants of surface water and groundwater. Waterborne viruses can be effectively inactivated by oxidants, such as those generated in Fenton-like systems. However, the mechanisms by which this inactivation oc ...

2020

Photoredox-Catalyzed Decarboxylation for the Transfer of Alkynes and Nitriles Using Hypervalent Iodine Reagents

Franck Le Vaillant

Aliphatic alkynes and nitriles are privileged motifs in organic chemistry. Therefore, alkynes and nitriles have played a central role for the exploration and development of novel strategies to forge C-C bonds in efficient manner. They are broadly used as v ...

EPFL2019

Experimental evidence for long-range stabilizing and destabilizing interactions between charge and radical sites in distonic ions

Ganna Gryn'ova

Polarizable radical sites in distonic radical anions are stabilized by ostensibly remote negative charges. Computational evidence suggests bond dissociation energies of closed-shell precursors are significantly lowered by through-space interactions with a ...

ELSEVIER SCIENCE BV2019