How Cations - Silica Surface Interactions Affect Water Dynamics in Nanoconfined Electrolyte Solutions

Probing electrolytes behavior at the atomic level provides valuable insights into understanding the reactive transport of electrolyte solutions in nanoconfinement and help explaining and predicting the macroscopic properties of industrial or natural nanoporous materials. In this study, we focused on the behavior of water and ions in 2.6 nm silica nanocylinders filled with electrolyte solutions, XCl at 1M with X = Li, Na and Cs, monovalent cations presenting various kosmotropic/chaotropic properties. Using a combination of experiments and theoretical modeling, we analyzed the water dynamics based on three primary effects: the confinement, the electrolyte, and the interfacial ions-porous material surface interaction. Comparing the water dynamics obtained with divalent cations previously studied by Baum et al., we highlight that monovalent cations present weaker interactions with silica surfaces than divalent cations. This significantly impacts the water dynamics in addition to the confinement and electrolyte effects. This study pinpoints the importance of ions behavior within the interfacial layer and its impact on water transport in nanoconfinement

How Cation–Silica Surface Interactions Affect Water Dynamics in Nanoconfined Electrolyte Solutions

International audienceProbing electrolyte behavior at the atomic level provides valuable insights into understanding the reactive transport of electrolyte solutions in nanoconfinement and help explain and predict the macroscopic properties of industrial or natural nanoporous materials. In this study, we focused on the behavior of water and ions in silica nanocylinders with a pore diameter of 2.6 nm filled with electrolyte solutions, XCl at 1 M with X = Li, Na, and Cs, monovalent cations presenting various kosmotropic/chaotropic properties. Using a combination of experiments and theoretical modeling, we analyzed the water dynamics based on three primary effects: the confinement, the electrolyte, and the interfacial ion–porous material surface interaction. Comparing the water dynamics obtained with those of divalent cations previously studied by Baum et al. (Dynamical and Structural Properties of Langmuir 35 (2019) 10780–10794. https://doi.org/10.1021/acs.langmuir.9b01434), we highlight that monovalent cations present weaker interactions with silica surfaces than divalent cations. This significantly impacts the water dynamics in addition to the confinement and electrolyte effects. This study pinpoints the importance of ion behavior within the interfacial layer and its impact on water transport in nanoconfinement

Les peintures murales du IIe s. p.C. de deux chambres d’une auberge d’Augustonemetum/Clermont-Ferrand

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Chapitre 2. Les premières périodes d’occupation (phase 1 : fin du ier siècle - fin du iie siècle)

La croissance d’Augustonemetum, à partir de la fin du Ier siècle ap. J.-C. et surtout au cours du IIe siècle, se traduit par la mise en chantier de plusieurs programmes monumentaux d’envergure (Dartevelle, Le Barrier 2016 : 546-552) et par l’investissement de ses marges, au-delà du premier noyau urbain centré sur la butte. C’est à cette période que remontent les plus anciennes constructions identifiées sur le site de l’ancienne Gare routière. Elles sont à l’origine de la création d’un quartie..

Phase transitions and spin dynamics of the quasi-one dimensional Ising-like antiferromagnet BaCo2V2O8 in a longitudinal magnetic field

By combining inelastic neutron scattering and numerical simulations, we study the quasi-one dimensional Ising-like quantum antiferromagnet BaCo$_{2}$V$_{2}$O$_{8}$ in a longitudinal magnetic field applied along the magnetic anisotropy axis, which is also the chain direction. The external field closes the excitation gap due to the magnetic anisotropy, inducing a transition from the N\'eel ordered state to an incommensurate longitudinal spin density wave phase. If the field is increased further, another transition into a transverse antiferromagnetic phase takes place at 9 T due to the competition between longitudinal and transverse correlations. We numerically and experimentally show that the model of XXZ chains connected by a weak interchain interaction well reproduces this transition. We also calculate the dynamical susceptibility and demonstrate that it agrees quantitatively with inelastic neutron scattering measurements. In contrast to the abrupt change of magnetic ordering, the spectra do not change much at the transition at 9 T, and the spin dynamics can be described as a Tomonaga-Luttinger liquid. We also refine the modeling of BaCo$_{2}$V$_{2}$O$_{8}$ by including a four-site periodic term arising from the crystal structure which enables to account for an anomaly of the magnetic susceptibility appearing at 19 T as well as for the anticrossing observed in the inelastic neutron scattering spectra.Comment: 13 pages, 8 figure

Extraction by solvent using microwave and ultrasound-assisted techniques followed by HPLC analysis of Harpagoside from Harpagophytum procumbens and comparison with conventional solvent extraction methods

This research paper presents a quick and ecofriendly technique for the extraction of harpagoside (HS), the active marker of Harpagophytum procumbens (HP), along with a comparison with conventional methods so as to propose an efficient HPLC method. HP is widely used as an anti-inflammatory in phytotherapy. The quality control of the herbal drug and extract calls for a time consuming method of conventional extraction, which involves a high consumption of solvents. In this study, HP has been extracted using conventional ultrasound (UAE) and microwave (MAE)-assisted methods. The effects have been examined based on several parameters of HS extraction efficiencies. An HPLC method with a core-shell column was developed in order to calculate the HS in HP. The flowratewas reduced by 4. The method of validation used is specific, linear, precise and accurate. MAE and UAE saved solvent consumption, time and energy. It has, therefore, been found that the combined UAE-HPLC process is convenient and appropriate for the quality control of HP