Publications related to Manganese dioxide

Microstructure - Electrochemical Surface Reactivity Relationship of Electrochemically Grown Manganese Oxides Films

This Thesis provides a comprehensive and correlative investigation of the microstructure, chemical state, and electrochemical reactivity of manganese oxide (MnOx) films, aiming to gain a deeper understanding of the deposition and dissolution mechanism of M ...

EPFL2024

Permanganate Reduction by Hydrogen Peroxide: Formation of Reactive Manganese Species and Superoxide and Enhanced Micropollutant Abatement

Urs von Gunten, Ke Xu

Permanganate (MnO4-, Mn(VII)) is widely applied at the initial stage of water treatment to, e.g., abate taste and odor compounds, Mn(II) and Fe(II). However, its selectivity limits its application for micropollutant abatement. Hydrogen peroxide (H2O2), whi ...

AMER CHEMICAL SOC2021

Direct Visualization of Atomic-Scale Heterogeneous Structure Dynamics in MnO2 Nanowires

Kangning Zhao, Xin Peng, Yuyang Zhang

Manganese oxides are attracting great interest owing to their rich polymorphism and multiple valent states, which give rise to a wide range of applications in catalysis, capacitors, ion batteries, and so forth. Most of their functionalities are connected t ...

AMER CHEMICAL SOC2021

Photo-induced environmental remediation, biomedical imaging, and microbial inactivation by Mn-doped semiconductors: critical issues

Juan Kiwi, Sami Rtimi

The Mn-doping/decoration of S-containing semiconductor quantum dots (QDs) determine their photochemical properties and are important in the field of artificial photosynthesis. The Mn-mediated charge-transfer kinetics and energetics in composites of the typ ...

ELSEVIER SCI LTD2021

Palladium Catalysed Intramolecular Carbo-oxygenation of Propargylic Amines to Access 1,2-Amino Alcohols and alpha-Amino Ketones via in situ Tether Formation

Phillip Gulliver Dominic Greenwood

a-Amino ketones and 1,2-amino alcohols are important structural motifs in organic chemistry, that can be observed in natural products, pharmaceutically and bioactive compounds. For these reasons, they constitute privileged targets for the development of ne ...

EPFL2020

Comparison of the impact of ozone, chlorine dioxide, ferrate and permanganate pre-oxidation on organic disinfection byproduct formation during post-chlorination

Urs von Gunten

Pre-oxidation is commonly used to mitigate the formation of byproducts during post-disinfection. A comparative study of the impact of four pre-oxidants, ozone (O-3), chlorine dioxide (ClO2), permanganate (Mn(vii)) and ferrate (Fe(vi)), on the formation of ...

ROYAL SOC CHEMISTRY2020

Efficiency of pre-oxidation of natural organic matter for the mitigation of disinfection byproducts: Electron donating capacity and UV absorbance as surrogate parameters

Urs von Gunten

Pre-oxidation is often used before disinfection with chlorine to decrease the reactivity of the water matrix and mitigate the formation of regulated disinfection byproducts (DBPs). This study provides insights on the impact of oxidative pre-treatment with ...

PERGAMON-ELSEVIER SCIENCE LTD2020

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

Urs von Gunten, Jun Ma, Jin Jiang, Yang Song, Yang Zhou

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

Manganese-mediated reductive amidation of esters with nitroarenes

Xile Hu, Chi Wai Cheung, Peng Wang, Ning Shen

Amides are ubiquitous molecules in nature and in synthetic chemistry. Here we report a convenient and efficient method to synthesize N-aryl amides via amidation of esters with nitroarenes. In the presence of manganese metal, this amidation proceeded smooth ...

ROYAL SOC CHEMISTRY2019

Manganese-Mediated Reductive Transamidation of Tertiary Amides with Nitroarenes

Xile Hu, Chi Wai Cheung

Amides are an important class of organic compounds, which have widespread industrial applications. Transamidation of amides is a convenient method to generate new amides from existing ones. Tertiary amides, however, are challenging substrates for transamid ...

2018

In Situ Formation of Free Chlorine During ClO2 Treatment: Implications on the Formation of Disinfection Byproducts

Urs von Gunten

Chlorine dioxide (ClO2) is commonly used as an alternative disinfectant to chlorine in drinking water treatment because it produces limited concentrations of halogenated organic disinfection byproducts. During drinking water treatment, the primary ClO2 byp ...

AMER CHEMICAL SOC2018

"Palladium-Catalyzed Diamination of Alkynes in Synthesis of Tetracycles" and "Copper-Catalyzed Cyanoalkylation of Unactivated Alkenes"

Minh Tu Ha

The thesis deals with the development of transition metal-catalyzed difunctionalization of alkenes and alkynes, which can be categorized into two major topics: (1) palladium-catalyzed diamination of alkynes for the synthesis of tetracycles; (2) copper-cata ...

EPFL2017

Building Composite Iron-Manganese Oxide Flowerlike Nanostructures: A Detailed Magnetic Study

Davide Deiana

Here we show that it is possible to produce different magnetic core multiple shell heterostructures from monodisperse Fe3O4 spherical magnetic seeds by finely controlling the amount of a manganese precursor and using, in a smart and simple way, a cation-ex ...

Amer Chemical Soc2017

Vertical changes of the Co and Mn speciation along a lateritic regolith developed on peridotites (New Caledonia)

Gabrielle Dublet, Vincent Noel

Because they can host significant amounts of Co, the Mn-oxides are commonly considered as the major Co-bearing mineral species in lateritic environments. However, little is known about the process leading to the formation and/or the weathering of these Co- ...

Pergamon-Elsevier Science Ltd2017

Genetic, structural and phenotypic properties of MS2 coliphage with resistance to ClO2 disinfection

Tamar Kohn, Anna Carratala Ripolles, Virginie Bachmann, Sergey Nazarov, Petr Leiman, Qingxia Zhong, Ricardo Cesar Guerrero Ferreira, Laura Piccinini

Common water disinfectants like chlorine have been reported to select for resistant viruses, yet little attention has been devoted to characterizing disinfection resistance. Here, we investigated the resistance of MS2 coliphage to inactivation by chlorine ...

Amer Chemical Soc2016

Impact of microbial Mn oxidation on the remobilization of bioreduced U(IV)

Rizlan Bernier-Latmani, Kelly Lee Plathe

Effects of Mn redox cycling on the stability of bioreduced U(IV) are evaluated here. U(VI) can be biologically reduced to less soluble U(IV) species and the stimulation of biological activity to that end is a salient remediation strategy; however, the stab ...

American Chemical Society2013

Chemical Oxidation of Dissolved Organic Matter by Chlorine Dioxide, Chlorine, And Ozone: Effects on Its Optical and Antioxidant Properties

Urs von Gunten, Silvio Canonica

In water treatment dissolved organic matter (DOM) is typically the major sink for chemical oxidants. The resulting changes in DOM, such as its optical properties have been measured to follow the oxidation processes. However, such measurements contain only ...

Amer Chemical Soc2013

Manganese Oxidation Induced by Water Table Fluctuations in a Sand Column

Janet Gordon Hering

On off cycles of production wells, especially in bank filtration settings, cause oscillations in the local water table, which can deliver significant amounts of dissolved oxygen (DO) to the shallow groundwater. The potential for DO introduced in this manne ...

2012

Trade-Offs in Disinfection Byproduct Formation Associated with Precursor Preoxidation for Control of N-Nitrosodimethylamine Formation

Urs von Gunten

Chloramines in drinking water may form N-nitrosodimethylamine (NDMA). Various primary disinfectants can deactivate NDMA precursors prior to chloramination. However, they promote the formation of other byproducts. This study compared the reduction in NDMA f ...

2012

Formation of assimilable organic carbon during oxidation of natural waters with ozone, chlorine dioxide, chlorine, permanganate, and ferrate

Urs von Gunten

Five oxidants, ozone, chlorine dioxide, chlorine, permanganate, and ferrate were studied with regard to the formation of assimilable organic carbon (AOC) and oxalate in absence and presence of cyanobacteria in lake water matrices. Ozone and ferrate formed ...

2011