Preparation and Characterization of Natural Deep Eutectic Solvents (NADESs): Application in the Extraction of Phenolic Compounds from Araza Pulp ().

Natural deep eutectic solvents (NADESs) of choline chloride (ChCl) and fructose, glucose, citric and malic acid with different water concentration were prepared and characterized. The pH ranged from 2.34 to 7.

Elaboration and Characterization of Natural Deep Eutectic Solvents (NADESs): Application in the Extraction of Phenolic Compounds from .

In this paper, natural deep eutectic solvents (NADESs) with lactic acid, glycine, ammonium acetate, sodium acetate, and choline chloride were prepared with and without the addition of water. NADES formation was evaluated using FTIR and Raman, where hydrogen bonds were identified between the hydroxyl group of lactic acid and the amino and carboxyl groups of glycine. Acetate and ammonium ions were also identified as forming bonds with lactic acid.

Elucidating the phase transitions of decanoic-acid crystal by XRD, Raman, group theory and Gibbs energy analyses combined with DFT calculations.

This research reports a series of phase transitions in the decanoic-acid (DA) crystal under low-temperature conditions, which were elucidated by XRD, Raman scattering and DFT calculations in a dimer of DA in the C form (monoclinic structure). The first phase change was noticed within the 210-190 K interval duly characterized as a transition of second-order type, as indicated by Gibbs energy behavior, suggesting that the monoclinic structure (P2/c) of the crystal is not changed. The second change was observed nearly 110-90 K, whose transition is first-order type occurring from the C form to an A form (triclinic), possibly belonging to the P1 space group.

Multilayered iron oxide/reduced graphene oxide nanocomposite electrode for voltammetric sensing of bisphenol-A in lake water and thermal paper samples.

A multilayered iron oxide/reduced graphene oxide (ION-RGO) nanocomposite electrode is reported for the voltammetric sensing of bisphenol-A (BPA). Structural characterizations reveal the nanocomposite features RGO sheets decorated with nanometric spherical ION in a mixture of maghemite and magnetite phases. ITO substrate modified with the ION-RGO multilayered film exhibits strong electrocatalytic effect toward BPA oxidation, which is made possible by Fe(III) catalysts generated at the ION's surface after scanning the electrode potential from below 0 V (vs Ag/AgCl) and followed by the RGO phase conducting the transferred electrons.

Starch-Mediated Immobilization, Photochemical Reduction, and Gas Sensitivity of Graphene Oxide Films.

This work unveils the roles played by potato starch (ST) in the immobilization, photochemical reduction, and gas sensitivity of graphene oxide (GO) films. The ST/GO films are assembled layer by layer (LbL) onto quartz substrates by establishing mutual hydrogen bonds that drive a stepwise film growth, with equal amounts of materials being adsorbed in each deposition cycle. Afterward, the films are photochemically reduced with UV irradiation (254 nm), following a first-order kinetics that proceeds much faster when GO is assembled along with ST instead of a nonoxygenated polyelectrolyte, namely, poly(diallyl dimethylammonium) hydrochloride (PDAC).

Phase Transition in all-trans-β-Carotene Crystal: Temperature-Dependent Raman Spectra.

In this study, we studied the stability of an all-trans-β-carotene single crystal using Raman spectroscopy with line excitation at 632.8 nm, in the temperature range 20–300 K. The Raman spectra exhibit clear modifications in the spectral range of the lattice and internal vibrational modes.

Thermal and electrical properties of starch-graphene oxide nanocomposites improved by photochemical treatment.

Bionanocomposite films have been prepared by casting an aqueous suspension of acetylated starch (ST) and poly(vinyl alcohol) (PVA) loaded with graphene oxide (GO). A photochemical and reagentless method has been successfully performed to convert the GO phase into reduced graphene oxide (RGO). The nanocomposites have displayed improved thermal and electrical properties when the amount of the GO phase is increased and properly converted to RGO.