Publications associées à Sulfate

Contradict mechanism of long-term magnesium and sodium sulfate attacks of nano silica-modified cement mortars - Experimental and thermodynamic modeling

The mechanisms of external sulfate attack on cement mortars containing nano silica have been studied under full immersion conditions after 3 years. The sulfate degradation processes were compared between sodium sulfate and magnesium sulfate solutions with ...

Elsevier Sci Ltd2024

Design and Synthesis of Bio-based Amphiphiles from Lignocellulosic Biomass

Songlan Sun

In the pursuit of a carbon-neutral chemical industry, minimizing fossil feedstock consumption while integrating renewable carbon sources is imperative. Surfactants, inherently amphiphilic, pose challenges in separation and recovery processes. Given their e ...

EPFL2024

Unidirectional penetration approach for characterizing sulfate attack mechanisms on cement mortars and pastes

Karen Scrivener, Qiao Wang, William Wilson

Degradation of cementitious materials by sulfate ions is commonly classified into chemical and physical sulfate attack. So-called "physical" attack dominates in many field situations, but laboratory testing focuses on "chemical" attack under full-immersion ...

Pergamon-Elsevier Science Ltd2023

Iodine oxoacids enhance nucleation of sulfuric acid particles in the atmosphere

Andrea Baccarini, Imad El Haddad, Mihnea Surdu, Lubna Dada, André Welti, Houssni Lamkaddam

The main nucleating vapor in the atmosphere is thought to be sulfuric acid (H2SO4), stabilized by ammonia (NH3). However, in marine and polar regions, NH3 is generally low, and H2SO4 is frequently found together with iodine oxoacids [HIOx, i.e., iodic acid ...

American Association for the Advancement of Science2023

Sulfur-cycling chemolithoautotrophic microbial community dominates a cold, anoxic, hypersaline Arctic spring

Ianina Altshuler

Background Gypsum Hill Spring, located in Nunavut in the Canadian High Arctic, is a rare example of a cold saline spring arising through thick permafrost. It perennially discharges cold (similar to 7 degrees C), hypersaline (7-8% salinity), anoxic (similar ...

BMC2023

Insights on the role of alumina content and the filler effect on the sulfate requirement of PC and blended cements

Karen Scrivener, Franco Alberto Zunino Sommariva

Understanding the mechanism controlling the sulfate requirement of blended cements is crucial for a successful deployment of these technologies towards a more sustainable industry. Particularly, clarification regarding the role of alumina content on the su ...

Pergamon-Elsevier Science Ltd2022

Effect of different ions on dissolution rates of silica and feldspars at high pH

Karen Scrivener, Barbara Lothenbach, Mahsa Bagheri, Mahdieh Shakoorioskooie

The dissolution kinetics of silica-containing minerals in aggregates influences strongly the process of ASR in concrete. In this paper, the effect of different ions on the dissolution rates of SiO2 (amorphous and quartz) and feldspars at high pH values was ...

Pergamon-Elsevier Science Ltd2022

Meta-omics-aided isolation of an elusive anaerobic arsenic-methylating soil bacterium

Rizlan Bernier-Latmani, Karin Lederballe Meibom, Karen Elda Viacava Romo, Nicolas Louis Maurice Jacquemin, Matthew Charles Reid, Jiangtao Qiao

Soil microbiomes harbor unparalleled functional and phylogenetic diversity and are sources of novel metabolisms. However, extracting isolates with a targeted function from complex microbiomes is not straightforward, particularly if the associated phenotype ...

2022

Resistance of cementitious materials to sulfate attack: quantifying performance with a reliable unidirectional approach

Qiao Wang

Depending on the environmental conditions, concrete materials can come into contact with sulfate ions which are widely present in rivers, underground water, sewers, seawater and soil. Sulfates can react with the cement paste in concrete and cause damage wh ...

EPFL2022

Poisoning of Mn-Ce/AC catalysts for low-temperature NH3-SCR of NO by K+ and its counter-ions (Cl- /NO3- /SO42- )

Oliver Kröcher, Davide Ferri, Rob Jeremiah G. Nuguid, Jie Yang

Mn-Ce/AC catalysts for low-temperature NH3-SCR of NOx were deliberately loaded with various potassium salts (KCl, KNO3, and K2SO4) to investigate the influence of the counter-ions on the poisoning impact. Whereas K salts poisoning had only marginal impact ...

ELSEVIER2022

Molecular dynamics simulations of the evaporation of hydrated ions from aqueous solution

Philip Robin Loche

Although important for atmospheric processes and gas-phase catalysis, very little is known about the hydration state of ions in the vapor phase. Here we study the evaporation energetics and kinetics of a chloride ion from liquid water by molecular dynamics ...

NATURE PORTFOLIO2022

Active lithoautotrophic and methane-oxidizing microbial community in an anoxic, sub-zero, and hypersaline High Arctic spring

Ianina Altshuler

Lost Hammer Spring, located in the High Arctic of Nunavut, Canada, is one of the coldest and saltiest terrestrial springs discovered to date. It perennially discharges anoxic (

2022

Atomistic Simulation of Cementitious Systems: An Insight Into Adsorption of Ions and Small Molecules Onto Portlandite and C-S-H Surfaces

Masood Valavi

Calcium-Silicate-Hydrate (C-S-H) has been studied extensively over the last few decades to gain understanding toward the underlying mechanism of different stages during cement hydration. The variable stoichiometry and nanocrystallinity of C-S-H makes it di ...

EPFL2022

Growth and persistence of an aerobic microbial community in Wyoming bentonite MX-80 despite anoxic in-situ conditions

Rizlan Bernier-Latmani, Manon Frutschi, Niels Burzan, Roberta Murad Lima

Microbial activity has the potential to enhance the corrosion of high-level radioactive waste disposal canisters, which, in the proposed Swiss deep geological repository, will be embedded in bentonite and placed in the Opalinus Clay rock formation (OPA). T ...

Frontiers Media SA2022

Pan-Arctic seasonal cycles and long-term trends of aerosol properties from 10 observatories

Julia Schmale, Jakob Boyd Pernov

Even though the Arctic is remote, aerosol properties observed there are strongly influenced by anthropogenic emissions from outside the Arctic. This is particularly true for the so-called Arctic haze season (January through April). In summer (June through ...

Copernicus Publications2022

Seasonal Aerosol Acidity, Liquid Water Content and Their Impact on Fine Urban Aerosol in SE Canada

Athanasios Nenes, Andrea Mario Arangio

This study explores the drivers of aerosol pH and their impact on the inorganic fraction and mass of aerosol in the S.E. Canadian urban environments of Hamilton and Toronto, Ontario. We find that inter-seasonal pH variability is mostly driven by temperatur ...

MDPI2022

Strength-promoting mechanism of alkanolamines on limestone-calcined clay cement and the role of sulfate

Karen Scrivener, François Henri Avet, Xuerun Li, Wilasinee Hanpongpun, Hong Huang

This paper reports the strength-promoting mechanism of alkanolamines on limestone-calcined clay cement (LC3). The hydration kinetics, phase formation and microstructure of LC3 with triethanolamine (TEA) or triisopropanolamine (TIPA) were investigated. TEA ...

Pergamon-Elsevier Science Ltd2021

Differentiation of coarse-mode anthropogenic, marine and dust particles in the High Arctic islands of Svalbard

Julia Schmale

Understanding aerosol–cloud–climate interactions in the Arctic is key to predicting the climate in this rapidly changing region. Whilst many studies have focused on submicrometer aerosol (diameter less than 1 µm), relatively little is known about the super ...

Copernicus Publications2021

Aggregate dissolution in different pore solutions

Mahsa Bagheri

The occurrence of cracking due to alkali silica reaction (ASR) affects the service life of concrete structures. The dissolution of silica-containing minerals within aggregates causes the formation of ASR products, which fill macroscopic cracks and cause th ...

EPFL2021

Factors influencing the sulfate balance in pure phase C3S/C(3)A systems

Karen Scrivener, Franco Alberto Zunino Sommariva

Understanding the sulfate balance mechanism of cement is needed for an effective use of sustainable blended cements. Pure phase systems allow to study the interaction between sulfate and each of the phases involved in early age hydration separately. This p ...

Pergamon-Elsevier Science Ltd2020