Decreasing Hygroscopicity Slows Forsterite Carbonation under Low-Water Conditions.

A fundamental understanding of processes that slow divalent metal silicate carbonation is important for developing effective strategies to durably store carbon dioxide and mitigate atmospheric CO. This study presents a detailed investigation of a passivation effect unique to low-water conditions during the carbonation of forsterite (MgSiO) and highlights the importance of hygroscopicity in influencing metal silicate carbonation. Integrated in situ and ex situ experimental results showed that the decrease in the carbonation rate of forsterite observed after ∼10 h in humid supercritical CO (50 °C, 90 bar) correlates with a reduction in water film thickness, and in particular, weakly hydrogen bonded adsorbed water that facilitates ion transport.

Method to derive the infrared complex refractive indices n(λ) and k(λ) for organic solids from KBr pellet absorption measurements.

Obtaining the complex refractive index vectors (~) and (~) allows calculation of the (infrared) reflectance spectrum that is obtained from a solid in any of its many morphological forms. We report an adaptation to the KBr pellet technique using two gravimetric dilutions to derive quantitative (~)/(~) for dozens of powders with greater repeatability. The optical constants of bisphenol A and sucrose are compared to those derived by other methods, particularly for powdered materials.

Interlayer Cation Polarizability Affects Supercritical Carbon Dioxide Adsorption by Swelling Clays.

Several strategies for mitigating the build-up of atmospheric carbon dioxide (CO) bring wet supercritical CO (scCO) in contact with phyllosilicates such as illites and smectites. While some work has examined the role of the charge-balancing cation and smectite framework features on CO/smectite interactions, to our knowledge no one has examined how the polarizability of the charge-balancing cation influences these behaviors. In this paper, the scCO adsorption properties of Pb, Rb, and NH saturated smectite clays at variable relative humidity are studied by integrating in situ high-pressure X-ray diffraction (XRD), infrared spectroscopic titrations, and magic angle spinning nuclear magnetic resonance (MAS NMR) methods.

Influence of intermolecular interactions on the infrared complex indices of refraction for binary liquid mixtures.

This paper investigates the accuracy of deriving the composite optical constants of binary mixtures from only the complex indices of refraction of the neat materials. These optical constants enable the reflectance spectra of the binary mixtures to be modeled for multiple scenarios (, different substrates, thicknesses, volume ratios), which is important for contact and standoff chemical detection. Using volume fractions, each mixture's complex index of refraction was approximated three different mixing rules.

Burn Intensity Drives the Alteration of Phenolic Lignin to (Poly) Aromatic Hydrocarbons as Revealed by Pyrolysis Gas Chromatography-Mass Spectrometry (Py-GC/MS).

High-intensity wildfires alter the chemical composition of organic matter, which is expected to be distinctly different from low-intensity prescribed fires. Herein, we used pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), in conjunction with solid-state C nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectroscopy, to assess chemical alterations from three wildfires and a long-term frequent prescribed fire site. Our results showed that black ash formed under moderate intensity burns contained less aromatic (ArH), polyaromatic hydrocarbon (PAH), and nitrogen-containing compounds (Ntg) but more lignin (LgC) and phenol compounds (PhC), compared to white ash formed under high intensity burns.

Microsized Pore Structure Determination in EPDM Rubbers Using High-Pressure Xe NMR Techniques.

Microsized pore parameters, such as pore size and distance between pores in a series of model EPDM rubbers, were determined under the pressure of 500 psi using Xe nuclear magnetic resonance (NMR) techniques: spin-lattice () and spin-spin () relaxation measurements, pulsed-field gradient (PFG) NMR, and two-dimensional exchange spectroscopy (2D EXSY). The / (≫1) ratio for the xenon confined in the pores is larger than that for nonconfined free xenon. This suggests that almost the entire pore surface interacts with xenon atoms like a closed pore.

Integrated Capture and Conversion of CO to Methane Using a Water-lean, Post-Combustion CO Capture Solvent.

Integrated carbon capture and conversion of CO into materials (IC M) is an attractive solution to meet global energy demand, reduce our dependence on fossil fuels, and lower CO emissions. Herein, using a water-lean post-combustion capture solvent, [N-(2-ethoxyethyl)-3-morpholinopropan-1-amine] (2-EEMPA), >90 % conversion of captured CO to hydrocarbons, mostly methane, is achieved in the presence of a heterogenous Ru catalyst under relatively mild reaction conditions (170 °C and <15 bar H pressure). The catalytic performance was better in 2-EEMPA than in aqueous 5 m monoethanol amine (MEA).

A Polymer-in-Salt Electrolyte with Enhanced Oxidative Stability for Lithium Metal Polymer Batteries.

The lithium (Li) metal polymer battery (LMPB) is a promising candidate for solid-state batteries with high safety. However, high voltage stability of such a battery has been hindered by the use of polyethylene oxide (PEO), which oxidizes at a potential lower than 4 V versus Li. Herein, we adopt the polymer-in-salt electrolyte (PISE) strategy to circumvent the disadvantage of the PEO-lithium bis(fluorosulfonyl)imide (LiFSI) system with EO/Li ≤ 8 through a dry ball-milling process to avoid the contamination of the residual solvent.

Advanced Low-Flammable Electrolytes for Stable Operation of High-Voltage Lithium-Ion Batteries.

Despite being an effective flame retardant, trimethyl phosphate (TMP ) is generally considered as an unqualified solvent for fabricating electrolytes used in graphite (Gr)-based lithium-ion batteries as it readily leads to Gr exfoliation and cell failure. In this work, by adopting the unique solvation structure of localized high-concentration electrolyte (LHCE) to TMP and tuning the composition of the solvation sheaths via electrolyte additives, excellent electrochemical performance can be achieved with TMP -based electrolytes in Gr∥LiNi Mn Co O cells. After 500 charge/discharge cycles within the voltage range of 2.

Characterization of Dissolved Organic Matter from Wildfire-induced Microcystis aeruginosa Blooms controlled by Copper Sulfate as Disinfection Byproduct Precursors Using APPI(-) and ESI(-) FT-ICR MS.

Copper-based algaecides are usually used for controlling algae bloom triggered by the elevated levels of nutrients after wildfires, resulting in the promoted reactivity of dissolved organic matter (DOM) in forming disinfectant byproducts (DBPs). To identify the best strategy for handling this source water, we employed Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to characterize the DBPs precursors after 4-d Microcystis aeruginosa bloom cultured with black (BE) and white (WE) ash water extracts under 0, 0.5, and 1.

Enabling Ether-Based Electrolytes for Long Cycle Life of Lithium-Ion Batteries at High Charge Voltage.

Lithium-ion batteries (LIBs) with high-nickel (Ni) content LiNiMnCoO ( + + = 1) (NMC with Ni ≥ 0.6) cathodes operated at high charge voltages have been considered as one of the most promising candidates for addressing the challenge of increasing energy density demand. Conventional LiPF-organocarbonate electrolytes exhibit incompatibility with such cell chemistries under certain testing conditions because of the instability of electrode/electrolyte interphases.

Controls of nature: Secondary, tertiary, and quaternary structure of the enamel protein amelogenin in solution and on hydroxyapatite.

Amelogenin, a protein critical to enamel formation, is presented as a model for understanding how the structure of biomineralization proteins orchestrate biomineral formation. Amelogenin is the predominant biomineralization protein in the early stages of enamel formation and contributes to the controlled formation of hydroxyapatite (HAP) enamel crystals. The resulting enamel mineral is one of the hardest tissues in the human body and one of the hardest biominerals in nature.

Infrared Optical Constants from Pressed Pellets of Powders: I. Improved and Values of (NH)SO from Single-Angle Reflectance.

In combination with other parameters, the real, (), and imaginary, (), components of the complex refractive index,  =  + i, can be used to simulate the optical properties of a material in different forms, e.g., its infrared spectra.

The energetic basis for hydroxyapatite mineralization by amelogenin variants provides insights into the origin of .

Small variations in the primary amino acid sequence of extracellular matrix proteins can have profound effects on the biomineralization of hard tissues. For example, a change in one amino acid within the amelogenin protein can lead to drastic changes in enamel phenotype, resulting in , enamel that is defective and easily damaged. Despite the importance of these undesirable phenotypes, there is very little understanding of how single amino acid variation in amelogenins can lead to malformed enamel.

Temperature dependent structure and dynamics in smectite interlayers: Na MAS NMR spectroscopy of Na-hectorite.

Na MAS NMR spectroscopy of the smectite mineral hectorite acquired at temperatures from -120 °C to 40 °C in combination with the results from computational molecular dynamics (MD) simulations show the presence of complex dynamical processes in the interlayer galleries that depend significantly on their hydration state. The results indicate that site exchange occurs within individual interlayers that contain coexisting 1 and 2 water layer hydrates in different places. We suggest that the observed dynamical averaging may be due to motion of water volumes comparable to the dripplons recently proposed to occur in hydrated graphene interlayers (Yoshida , 2018, , 1496).

Genesis and Stability of Hydronium Ions in Zeolite Channels.

The catalytic sites of acidic zeolite are profoundly altered by the presence of water changing the nature of the Brønsted acid site. High-resolution solid-state NMR spectroscopy shows water interacting with zeolite Brønsted acid sites, converting them to hydrated hydronium ions over a wide range of temperature and thermodynamic activity of water. A signal at 9 ppm was observed at loadings of 2-9 water molecules per Brønsted acid site and is assigned to hydrated hydronium ions on the basis of the evolution of the signal with increasing water content, chemical shift calculations, and the direct comparison with HClO in water.

Solid-State NMR Identification of Intermolecular Interactions in Amelogenin Bound to Hydroxyapatite.

Biomineralization processes govern the formation of hierarchical hard tissues such as bone and teeth in living organisms, and mimicking these processes could lead to the design of new materials with specialized properties. However, such advances require structural characterization of the proteins guiding biomineral formation to understand and mimic their impact. In their "active" form, biomineralization proteins are bound to a solid surface, severely limiting our ability to use many conventional structure characterization techniques.

Tipping Point for Expansion of Layered Aluminosilicates in Weakly Polar Solvents: Supercritical CO.

Layered aluminosilicates play a dominant role in the mechanical and gas storage properties of the subsurface, are used in diverse industrial applications, and serve as model materials for understanding solvent-ion-support systems. Although expansion in the presence of HO is well-known to be systematically correlated with the hydration free energy of the interlayer cation, particularly in environments dominated by nonpolar solvents (i.e.

Improving Stability of Zeolites in Aqueous Phase via Selective Removal of Structural Defects.

Missing silicon-oxygen bonds in zeolites are shown to be the cause for structural instability of zeolites in hot liquid water. Their selective removal drastically improved their structural stability as demonstrated using zeolite beta as example. The defects in the siloxy bonds were capped by reaction with trimethylchlorosilane, and Si-O-Si bonds were eventually formed.

Anion-Tunable Properties and Electrochemical Performance of Functionalized Ferrocene Compounds.

We report a series of ionically modified ferrocene compounds for hybrid lithium-organic non-aqueous redox flow batteries, based on the ferrocene/ferrocenium redox couple as the active catholyte material. Tetraalkylammonium ionic moieties were incorporated into the ferrocene structure, in order to enhance the solubility of the otherwise relatively insoluble ferrocene. The effect of various counter anions of the tetraalkylammonium ionized species appended to the ferrocene, such as bis(trifluoromethanesulfonyl)imide, hexafluorophosphate, perchlorate, tetrafluoroborate, and dicyanamide on the solubility of the ferrocene was investigated.

The Role of Cesium Cation in Controlling Interphasial Chemistry on Graphite Anode in Propylene Carbonate-Rich Electrolytes.

Despite the potential advantages it brings, such as wider liquid range and lower cost, propylene carbonate (PC) is seldom used in lithium-ion batteries because of its sustained cointercalation into the graphene structure and the eventual graphite exfoliation. Here, we report that cesium cation (Cs(+)) directs the formation of solid electrolyte interphase on graphite anode in PC-rich electrolytes through its preferential solvation by ethylene carbonate (EC) and the subsequent higher reduction potential of the complex cation. Effective suppression of PC-decomposition and graphite-exfoliation is achieved by adjusting the EC/PC ratio in electrolytes to allow a reductive decomposition of Cs(+)-(EC)m (1 ≤ m ≤ 2) complex preceding that of Li(+)-(PC)n (3 ≤ n ≤ 5).

The flexible structure of the K24S28 region of Leucine-Rich Amelogenin Protein (LRAP) bound to apatites as a function of surface type, calcium, mutation, and ionic strength.

Leucine-Rich Amelogenin Protein (LRAP) is a member of the amelogenin family of biomineralization proteins, proteins which play a critical role in enamel formation. Recent studies have revealed the structure and orientation of the N- and C-terminus of LRAP bound to hydroxyapatite (HAP), a surface used as an analog of enamel. The structure of one region, K24 to S28, was found to be sensitive to phosphorylation of S16, the only naturally observed site of serine phosphorylation in LRAP, suggesting that K24S28 may sit at a key region of structural flexibility and play a role in the protein's function.

A common intermediate for N2 formation in enzymes and zeolites: side-on Cu-nitrosyl complexes.

Side on! Combined FTIR and NMR studies revealed the presence of a side-on nitrosyl species in the zeolite Cu-SSZ-13. This intermediate is very similar to those found in nitrite reductase enzyme systems. The identification of this intermediate led to the proposal of a reaction mechanism that is fully consistent with the results of both kinetic and spectroscopic studies.

Studies of Secondary Melanoma on C57BL/6J Mouse Liver Using 1H NMR Metabolomics.

NMR metabolomics, consisting of solid state high resolution magic angle spinning (HR-MAS) 1H-NMR, liquid state high resolution 1H-NMR, and principal components analysis (PCA) has been used to study secondary metastatic B16-F10 melanoma in C57BL/6J mouse liver. The melanoma group can be differentiated from its control group by PCA analysis of the estimates of absolute concentrations from liquid state 1H-NMR spectra on liver tissue extracts or by the estimates of absolute peak intensities of metabolites from 1H HR-MAS-NMR data on intact liver tissues. In particular, we found that the estimates of absolute concentrations of glutamate, creatine, fumarate and cholesterol are elevated in the melanoma group as compared to controls, while the estimates of absolute concentrations of succinate, glycine, glucose, and the family of linear lipids including long chain fatty acids, total choline and acyl glycerol are decreased.