Personne :
Larivière, Dominic

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Université Laval. Département de chimie
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Voici les éléments 1 - 7 sur 7
  • Publication
    Accès libre
    Revealing the hydrolysis mechanism of a Hg2+-reactive fluorescein probe : novel insights on thionocarbonated dyes
    (American Chemical Society, 2019-12-31) Picard-Lafond, Audrey; Boudreau, Denis; Larivière, Dominic
    As one of the most toxic metal pollutants, mercury is the subject of extensive research to improve current detection strategies, notably to develop sensitive, selective, fast, and affordable Hg2+-responsive fluorescent probes. Comprehending the sensing mechanism of these molecules is a crucial step in their design and optimization of their performance. Herein, a new fluorescein-based thionocarbonate-appended Hg2+-sensitive probe was synthesized to study the hydrolysis reactions involved in the sensing process. Autohydrolysis was revealed as a significant component of the signal generation mechanism, occurring concurrently with Hg2+-catalyzed hydrolysis. This knowledge was used to investigate the effects of key experimental conditions (pH, temperature, chloride ions) on sensing efficiency. Overall, the chemical and physical properties of this new thionocarbonated dye and the insights into its sensing mechanism will be instrumental in designing reliable and effective portable sensing strategies for mercury and other heavy metals.
  • Publication
    Accès libre
    Determination of Pb in environmental samples after cloud point extraction using crown ether
    (Elsevier, 2017-11-11) Blanchet-Chouinard, Guillaume; Larivière, Dominic
    In the present study, a new cloud point extraction methodology based on the selective preconcentration and the extraction of stable lead in acidic conditions with 4′,4''(5'')-di-tert-butyldicyclohexano-18-crown-6 as a chelating agent was developed, optimized and validated. A mixture of Triton X-114 as non-ionic surfactant and CTAB as cationic surfactant was used to produce micellar structures that incorporate the chelating agent. Phase separation, induced by coacervation, was achieved by increasing the temperature of the system above the cloud point temperature. Pb extraction efficiency was maximized through an optimisation process where the effect of each parameter (i.e. non-ionic and ionic surfactant concentrations, pH, chelating agent concentration and cloud point temperature) on the chemical recoveries of Pb was assessed. Under optimum experimental conditions, the method reaches recoveries greater than 67% for Pb in a variety of complex matrices. In order to facilitate the quantification of Pb by plasma based instrumentations, a back-extraction procedure using aqueous solution of ammonium citrate were performed on the surfactant rich phase in order to reduce the effects on sample introduction and non-spectral interferences. LOD and LOQ of 0.8 µg L−1 and 2.6 µg L−1, respectively, were determined by ICP-OES for the complete procedure. Using the back-extraction approach, a preconcentration factor of 39 was achieved for an initial sample volume of 195 mL. The ruggedness of the methodology was validated by determining Pb concentration in various environmental and biological samples.
  • Publication
    Accès libre
    A metal-enhanced Hg2+-responsive fluorescent nanoprobe: from morphological design to application to natural waters
    (American Chemical Society, 2022-06-22) Picard-Lafond, Audrey; Boudreau, Denis; Larivière, Dominic
    Metal-enhanced fluorescence (MEF) is a powerful tool in the design of sensitive chemical sensors by improving brightness and photostability to target-responsive fluorophores. Compounding these advantages with the modest hardware requirements of fluorescent sensing compared to that of centralized elemental analysis instruments, expanding the use of MEF to the detection of low-level inorganic pollutants is a compelling aspiration. Among the latter, monitoring mercury in the environment, where some of its species disseminate through the food chain and, in time, to humans, has elicited a broad research effort towards the development of Hg2+-responsive fluorescent sensors. Herein, a Hg2+-sensitive MEF-enabled probe was conceived by grafting a Hg2+-responsive fluorescein derivative to concentric Ag@SiO2 NPs, where the metallic core enhances fluorescent emission of molecular probes embedded in a surrounding silica shell. Time-resolved fluorescence measurements showed that the fluorophore’s excited state lifetime decreases from 3.9 ns in a solid, coreless silica sphere, to 0.4 ns in the core-shell nanoprobe, granting the dye a better resistance to photobleaching. The Ag-core system showed a sizable improvement in limit of detection at 2 nM (0.4 ppb) compared to 50 nM (10 ppb) in the silica-only colloids and its effectiveness for natural water analysis was demonstrated. Overall, the reported nanoarchitecture hints at the potential of MEF for heavy metal detection by fluorescence detection.
  • Publication
    Accès libre
    Selective separation and preconcentration of Th(IV) using organo-functionalized, hierarchically porous silica monoliths
    (Royal Society of Chemistry (Great Britain), 2018-11-26) Giret, Simon; Fontaine, Frédéric-Georges; Meinusch, Rafael; Larivière, Dominic; Han, Jongho; Kleitz, Freddy; Hu, Yimu
    The potential application of thorium (Th) as nuclear fuel, as well as the environmental and public health concerns associated with it, promotes the development of economic and sustainable materials for the separation and removal of Th(IV) from minerals and environmental samples. In this work, centimeter-size, porous silica monoliths exhibiting hierarchical macroporosity–mesoporosity and a robust silica skeleton were prepared using a sol–gel process combined with post-synthetic hydrothermal treatment in ammonium hydroxide. Upon functionalization with diglycolamide (DGA), the resulting monolithic hybrid material was used as a column-type fixed bed sorbent for continuous flow extraction. An enhanced Th(IV) uptake from aqueous solution was achieved with a high enrichment factor and selectivity in the presence of competitive ions such as rare earth elements (REEs) and uranium (U). Systematic mechanistic studies show that the hierarchical pore system is crucial for enhanced adsorption kinetics and capacity. Two mineral leachates were used to assess the performances of the hybrid material, and despite the complex ion matrix and high ionic composition, the sorbent shows highly efficient recovery of Th(IV). The material was able to undergo 10 extraction–stripping–regeneration cycles, which bodes well for potential industrial applications.
  • Publication
    Accès libre
    Highly efficient and selective recovery of rare earth elements using mesoporous silica functionalized by preorganized chelating ligands
    (American Chemical Society, 2017-10-02) Drouin, Élisabeth; Fontaine, Frédéric-Georges; Larivière, Dominic; Kleitz, Freddy; Hu, Yimu
    Separating the rare earth elements (REEs) in an economically and environmentally sustainable manner is one of the most pressing technological issues of our time. Herein, a series of preorganized bidentate phthaloyl diamide (PA) ligands was synthesized and grafted on large-pore 3-dimensional (3-D) KIT-6 mesoporous silica. The synthesized sorbents were fully characterized by N2 physisorption, FT-IR, 13C cross-polarization (CP) and 29Si magic-angle spinning (MAS) NMR, thermogravimetric analysis-differential thermal analysis (TGA-DTA), and elemental analysis. Overall, the grafting of PA-type ligands was found to have significantly improved the extraction performance of the sorbents toward REEs compared to the homogeneous analogues. Specifically, the sorbent modified with the 1,2-phtaloyl ligand shows high preference over lanthanides with smaller size, whereas the 1,3-phtaloyl ligand exhibits selectivity toward elements with larger ion radius. This selectivity drastically changes from the homogeneous models that do not exhibit any selectivity. The possibility of regenerating the mesoporous sorbents through simple stripping using oxalate salt is demonstrated over up to 10 cycles with no significant loss in REEs extraction capacity, suggesting adequate chemical and structural stability of the new sorbent materials. Despite the complex ion matrix and high ionic composition, the exposure of industrial mining deposits containing REEs to the sorbents results in selective recovery of target REEs.
  • Publication
    Accès libre
    Recent advances in the separation of rare earth elements using Mesoporous hybrid materials
    (Wiley, 2018-05-27) Fontaine, Frédéric-Georges; Larivière, Dominic; Kleitz, Freddy; Hu, Yimu
    Over the past decades, the need for rare earth elements (REEs) has increased substantially, mostly because these elements are used as valuable additives in advanced technologies. However, the difference in ionic radius between neighboring REEs is small, which renders an efficient sized‐based separation extremely challenging. Among different types of extraction methods, solid‐phase extraction (SPE) is a promising candidate, featuring high enrichment factor, rapid adsorption kinetics, reduced solvent consumption and minimized waste generation. The great challenge remains yet to develop highly efficient and selective adsorbents for this process. In this regard, ordered mesoporous materials (OMMs) possess high specific surface area, tunable pore size, large pore volume, as well as stable and interconnected frameworks with active pore surfaces for functionalization. Such features meet the requirements for enhanced adsorbents, not only providing huge reactional interface and large surface capable of accommodating guest species, but also enabling the possibility of ion‐specific binding for enrichment and separation purposes. This short personal account summarizes some of the recent advances in the use of porous hybrid materials as selective sorbents for REE separation and purification, with particular attention devoted to ordered mesoporous silica and carbon‐based sorbents.
  • Publication
    Accès libre
    Selective recovery of rare earth elements using chelating ligands grafted on mesoporous surfaces
    (Royal Society of Chemistry, 2015-11-25) Mushtaq, Ambreen; Fontaine, Frédéric-Georges; Larivière, Dominic; Florek, Justyna Agata; Cantin, Gabrielle; Kleitz, Freddy
    Nowadays, rare earth elements (REEs) and their compounds are critical for the rapidly growing advanced technology sectors and clean energy demands. However, their separation and purification still remain challenging. Among different extracting agents used for REE separation, the diglycolamide (DGA)-based materials have attracted increasing attention as one of the most effective extracting agents. In this contribution, a series of new and element-selective sorbents were generated through derivatisation of the diglycolamide ligand (DGA), grafted to mesoporous silica and tested for the separation of rare earth elements. It is shown that, by tuning the ligand bite angle and its environment, it is possible to improve the selectivity towards specific rare earth elements.