Structural evolution of water and hydroxyl groups during thermal, mechanical and chemical treatment of high purity natural quartz

Gaweł, Bartłomiej; Ulvensøen, Anna; Łukaszuk, Katarzyna; Arstad, Bjørnar; Muggerud, Astrid Marie F.; Erbe, Andreas

doi:10.1039/d0ra05798c

Cited by 35 publications

(19 citation statements)

References 67 publications

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“…The broad peak at 3425 cm −1 was due to the O-H stretching vibrations due to hydrogen-bonded hydroxyl groups [ 48 ]. Further, another peak was observed at 3743 cm −1 that can be explained by the O-H stretching of the free hydroxyl groups [ 49 ]. The hydroxyl functional groups were in abundance in SO, CW, GG, and dp-CNC.…”

Section: Resultsmentioning

confidence: 99%

Development of Bigels Based on Date Palm-Derived Cellulose Nanocrystal-Reinforced Guar Gum Hydrogel and Sesame Oil/Candelilla Wax Oleogel as Delivery Vehicles for Moxifloxacin

Shaikh

Anis

Poulose

et al. 2022

Gels

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Bigels are biphasic semisolid systems that have been explored as delivery vehicles in the food and pharmaceutical industries. These formulations are highly stable and have a longer shelf-life than emulsions. Similarly, cellulose-based hydrogels are considered to be ideal for these formulations due to their biocompatibility and flexibility to mold into various shapes. Accordingly, in the present study, the properties of an optimized guar gum hydrogel and sesame oil/candelilla wax oleogel-based bigel were tailored using date palm-derived cellulose nanocrystals (dp-CNC). These bigels were then explored as carriers for the bioactive molecule moxifloxacin hydrochloride (MH). The preparation of the bigels was achieved by mixing guar gum hydrogel and sesame oil/candelilla wax oleogel. Polarizing microscopy suggested the formation of the hydrogel-in-oleogel type of bigels. An alteration in the dp-CNC content affected the size distribution of the hydrogel phase within the oleogel phase. The colorimetry studies revealed the yellowish-white color of the samples. There were no significant changes in the FTIR functional group positions even after the addition of dp-CNC. In general, the incorporation of dp-CNC resulted in a decrease in the impedance values, except BG3 that had 15 mg dp-CNC in 20 g bigel. The BG3 formulation showed the highest firmness and fluidity. The release of MH from the bigels was quasi-Fickian diffusion mediated. BG3 showed the highest release of the drug. In summary, dp-CNC can be used as a novel reinforcing agent for bigels.

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Section: Resultsmentioning

confidence: 99%

Development of Bigels Based on Date Palm-Derived Cellulose Nanocrystal-Reinforced Guar Gum Hydrogel and Sesame Oil/Candelilla Wax Oleogel as Delivery Vehicles for Moxifloxacin

Shaikh

Anis

Poulose

et al. 2022

Gels

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“…Typically, the weight loss occurs in stages (Figure 1a), and three types of water exist based on the differences in the activation energy [ 14,18 ] (Table S2, Supporting Information). They are (1) surface‐adsorbed water, [ 18,19 ] (2) structural water, [ 14,20 ] which is water molecule that constitutes the crystal structure, and (3) structural pseudo‐water, [ 14,20a,21 ] which is hydrogen‐containing species with an H:O stoichiometry other than 2:1, such as –OH group, [ 15,22 ] hydroxide, [ 23 ] and hydronium [ 14,24 ] (Figure 1c). Here H–Ti–O compound containing a large amount of confined water is first synthesized via hydrothermal reaction, resulting in a layered structure (denoted as HTO, Figure S1, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Enhancing Li‐Ion Transport in Solid Electrolytes by Confined Water

Wang

Xiao

et al. 2022

Small

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nents in a LIB, the electrolyte is key to LIB's power performance, durability, and safety. Despite liquid electrolytes being mostly used in LIBs, in recent years solid electrolytes (SEs) emerge as promising due to their intrinsic nonflammability and better thermodynamic stability. [1] The ion transport property of SEs, characterized by ionic conductivity or diffusivity, is one of the most important features of SEs because it governs the power performance and energy efficiency of solid-state LIBs. Another important property of SEs is their electrochemical stability window, which determines the voltage, therefore power and energy density of LIBs.Several classes of Li-ion SEs have been developed in the past decades, including oxides, sulfides, polymer, and oxide-polymer composites [2] (Table S1, Supporting Information). Among them, oxides are especially attractive because they have a good balance between high Li-ion conductivity and wide electrochemical stability window. [3] However, their Li-ion conductivity (10 −3 -10 −8 S cm −1 ) is still much lower than that of liquid electrolytes (≈10 −2 S cm −1 ). To address this challenge, various strategies have been proposed to increase the ionic conductivity of oxide SEs. The most common one is structural engineering by elemental substitution, including both cation substitution and anion substitution. [3,4] For example, many researchers try to substitute La 3+ and/or Ti 4+ in Li 3x La 2/3−x◻1/3−2x TiO 3 (LLTO). [3] However, most substitution Developing new oxide solid electrolytes with fast Li-ion transport and high stability is an important step to realize high-performance solid-state Li-ion batteries. Hydrate materials containing confined water widely exist in nature or can be easily synthesized. However, they have seldom been explored as Li-ion solid electrolytes due to the stereotype that the presence of water limits the electrochemical stability window of a solid electrolyte. In this work, it is demonstrated that confined water can enhance Li-ion transport while not compromising the stability window of solid electrolytes using Li-H-Ti-O quaternary compounds as an example system. Three Li-H-Ti-O quaternary compounds containing different amounts of confined water are synthesized, and their ionic conductivity and electrochemical stability are compared. The compound containing structural pseudo-water is demonstrated to have an ionic conductivity that is 2-3 order of magnitude higher than the water-free Li 4 Ti 5 O 12 and similar stability window. A solid-state battery is made with this new compound as the solid electrolyte, and good rate and cycling performance are achieved, which demonstrates the promise of using such confined-watercontaining compounds as Li-ion solid electrolytes. The knowledge and insights gained in this work open a new direction for designing solid electrolytes for future solid-state Li-ion batteries. Broadly, by confining water into solid crystal structures, new design freedoms for tailing the properties of ceramic materials are introduced, which cr...

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“…It is hypothesized that this increased accessibility of O 2 for the case of monolayer covered metal is caused by a difference in the structural dynamics of water at the water film / gas interface. It is well established for a series of metals, semiconductors and insulators, both in simulation and vibrational spectroscopic experiment [42–46] that strongly bound interfacial water has a different coordination of the water molecule compared to bulk water. Differences in water structure at the surface were also found for solvated Pd [46] .…”

Section: Resultsmentioning

confidence: 99%

Limiting Current Density of Oxygen Reduction under Ultrathin Electrolyte Layers: From the Micrometer Range to Monolayers

Zhong

Schulz²,

Wu³

et al. 2021

ChemElectroChem

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The oxygen reduction reaction (ORR) under ultrathin electrolyte layers is a key reaction in many processes, from atmospheric corrosion to energy conversion in fuel cells. However, the ORR current under ultrathin electrolyte layers is difficult to measure using conventional electrochemical methods. Hence, reliable data are scarce for the micrometer range and totally missing for the sub‐micrometer range of the electrolyte layer thickness. Here, we report a novel hydrogen‐permeation‐based approach to measure the ORR current underneath thin and ultrathin electrolyte layers. By using a Kelvin‐probe‐based measurement of the potential, which results from dynamic equilibrium of oxygen reduction and hydrogen oxidation, and the corresponding hydrogen charging current density, the full current‐potential relationship can be constructed. The results shed a new light on the nature of the limiting current density of ORR underneath ultrathin layers of electrolyte.

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Structural evolution of water and hydroxyl groups during thermal, mechanical and chemical treatment of high purity natural quartz

Abstract: In dry quartz stable closed liquid micron-size inclusions and newly formed OH groups were observed after thermal treatment.

Cited by 35 publications

References 67 publications

Development of Bigels Based on Date Palm-Derived Cellulose Nanocrystal-Reinforced Guar Gum Hydrogel and Sesame Oil/Candelilla Wax Oleogel as Delivery Vehicles for Moxifloxacin

Development of Bigels Based on Date Palm-Derived Cellulose Nanocrystal-Reinforced Guar Gum Hydrogel and Sesame Oil/Candelilla Wax Oleogel as Delivery Vehicles for Moxifloxacin

Enhancing Li‐Ion Transport in Solid Electrolytes by Confined Water

Limiting Current Density of Oxygen Reduction under Ultrathin Electrolyte Layers: From the Micrometer Range to Monolayers

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