Publications associées à Use of silicate minerals for long-term pH control during reductive dechlorination of high tetrachloroethene concentrations in continuous flow-through columns

New tools for phase segmentation and denoising of analytical STEM data for enhanced chemical sensitivity, applied to Earth mantle research

This thesis is dedicated to developing innovative methodologies that improve elemental quantification in scanning transmission electron microscopy (STEM) using energy-dispersive X-ray spectroscopy (EDXS). The primary motivation stems from a geochemistry pr ...

EPFL2023

Effect of alkali, aluminium and equilibration time on calcium-silicate-hydrates

Yu Yan

Calcium silicate hydrate (C-S-H) is the main hydration product in Portland and blended cements, and greatly affects durability and mechanical properties of the hydrated cement. In the presence of Al-rich supplementary cementitious materials (SCMs), C-(A-)S ...

EPFL2022

Two-dimensional atomically bridged nanoporous silicate-based membranes for gas separation

Mostapha Dakhchoune

The synthesis of molecular-sieving two-dimensional zeolitic membranes by the assembly of crystalline building blocks without resorting to the secondary growth process is highly desirable. The precise pore size for molecular sieving, ultrathin thickness, an ...

EPFL2021

Effect of alkali hydroxide on calcium silicate hydrate (C-S-H)

Karen Scrivener, Barbara Lothenbach, Émilie Michèle L'Hôpital, Sheng-Yu Yang, Yu Yan

This paper investigates the effect of KOH and NaOH on C-S-H structure and solubility. Both KOH and NaOH have a similar effect, they increase pH values and silicon concentrations, and decrease calcium concentrations. At higher alkali hydroxide concentration ...

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

The effect of alkali hydroxides and equilibration time on Al uptake by calcium silicate hydrates (C-S-H)

Sonya Barzgar

Cement production accounts for approximately 8% of man-made CO2 emissions. Lowering these CO2 emissions is currently one of the most important and urgent research topics within the cement community. To reduce these emissions, the Portland cement (PC) is pa ...

EPFL2021

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

Role of Iron Sulfide Phases in the Stability of Noncrystalline Tetravalent Uranium in Sediments

Rizlan Bernier-Latmani, Luca Loreggian

Uranium (U) in situ bioremediation has been investigated as a cost-effective strategy to tackle U contamination in the subsurface. While uraninite was believed to be the only product of bioreduction, numerous studies have revealed that noncrystalline U(IV) ...

AMER CHEMICAL SOC2020

In Situ Biostimulation of Cr(VI) Reduction in a Fast-Flowing Oxic Aquifer

Rizlan Bernier-Latmani, Daniel Scott Alessi

Hexavalent chromium is among the most common and hazardous inorganic contaminants in soils and groundwater. A promising in situ bioremediation approach is the delivery of electron donors to stimulate microbially mediated Cr(VI) reduction, producing relativ ...

AMER CHEMICAL SOC2020

Effect of Aging on the Stability of Microbially Reduced Uranium in Natural Sediment

Rizlan Bernier-Latmani, Barbora Bártová, Agnès Novotny, Yuheng Wang, Sophie Louise Bretagne, Luca Loreggian

Reductive immobilization of uranium has been explored as a remediation strategy for the U-contaminated subsurface. Via the in situ biostimulation of microbial processes, hexavalent U is reduced to less soluble tetravalent species, which are immobilized wit ...

2019

Chlorinated ethene plume evolution after source thermal remediation: Determination of degradation rates and mechanisms

Christof Holliger, Julien Maillard, Jérémy Zimmermann, Alexandra Marie Murray

The extent, mechanism(s), and rate of chlorinated ethene degradation in a large tetrachloroethene (PCE) plume were investigated in an extensive sampling campaign. Multiple lines of evidence for this degradation were explored, including compound-specific is ...

ELSEVIER2019

Contaminant loading and competitive access of Pb, Zn and Mn(III) to vacancy sites in biogenic MnO2

Jasquelin Peña, Louise Helene Soegaard Jensen

The scavenging properties of MnO2 are largely attributed to sorption on layer vacancy sites. However, co-occurrence of Mn(II, III) with MnO2 can change mineral reactivity by modifying its Mn(III) content or number of free vacancy sites. These processes are ...

2018

Calcium phosphate formation on titanium-based surfaces: bioactivity evaluated by in vitro methods

Weitian Zhao

The prediction of implant behaviors in vivo by the use of easy-to-perform in vitro methods is of great interest in biomaterials research. In the field of bone implants, it is commonly accepted that a spontaneous formation of a hydroxyapatite (HA) layer on ...

EPFL2018

Selecting the best AOP for isoxazolyl penicillins degradation as a function of water characteristics: Effects of pH, chemical nature of additives and pollutant concentration

César Pulgarin, Paola Villegas Guzman

To provide new insights toward the selection of the most suitable AOP for isoxazolyl penicillins elimination, the degradation of dicloxacillin, a isoxazolyl penicillin model, was studied using different advanced oxidation processes (AOPs): ultrasound (US), ...

Elsevier2017

Alkali uptake in calcium alumina silicate hydrate (C-A-S-H)

Karen Scrivener, Barbara Lothenbach, Émilie Michèle L'Hôpital

Uptake of the alkalis K and Na by calcium silicate hydrate (C-S-H) and calcium alumina silicate hydrate (C-A-S-H) of molar Ca/Si ratios = 0.6 to 1.6 and molar Al/Si ratio = 0 or 0.05 has been studied at 20 degrees C. Alkalis are thought to be bound in the ...

Pergamon-Elsevier Science Ltd2016

Reduction and immobilization of uranium in the subsurface : controls, mechanisms, and implications for in situ bioremediation

Malgorzata Alicja Stylo

Decades of uranium (U) mining, milling and military use left a legacy of U contamination around the world. The radioactivity and chemical toxicity of U at contaminated sites pose an acute and long-term hazard to human health and the surrounding environment ...

EPFL2015

Environmental Mineralogy: New challenges, new materials

Rizlan Bernier-Latmani

The close links between mineralogy and materials science are leading to major developments in how society deals more effectively with energy and environmental challenges. The fast expanding field of "environmental mineralogy" helps mitigate major environme ...

Mineralogical Soc Amer2015

Control of groundwater pH during bioremediation: Improvement and validation of a geochemical model to assess the buffering potential of ground silicate minerals

Christof Holliger, David Andrew Barry, Alessandro Brovelli, Elsa Marina Lacroix

Accurate control of groundwater pH is of critical importance for in situ biological treatment of chlorinated solvents. The use of ground silicate minerals mixed with groundwater is an appealing buffering strategy as silicate minerals may act as long-term s ...

Elsevier2014

Use of silicate minerals for pH control during reductive dechlorination of chloroethenes in batch cultures of different microbial consortia

Christof Holliger, David Andrew Barry, Alessandro Brovelli, Elsa Marina Lacroix

In chloroethene-contaminated sites undergoing in situ bioremediation, groundwater acidification is a frequent problem in the source zone, and buffering strategies have to be implemented to maintain the pH in the neutral range. An alternative to conventiona ...

American Society for Microbiology2014

Using Silicate Mineral Particles for pH Control during in situ Bioremediation of Chlorinated Ethene Source Zones

Elsa Marina Lacroix

Soil and groundwater pollution by chlorinated solvents such as tricholorethene (TCE) and tetrachloroethene (PCE) is a frequent problem in the industrialized world. Chlorinated solvents, characterized by a low solubility and a density greater than water, fo ...

EPFL2013