Brandonmaclean3668

This study aimed to develop a highly efficient nanofilter for capturing fine particles using electrostatic forces. Poly(vinyl alcohol) (PVA), a water-soluble synthetic polymer, was selected as the main component of the filter because it can be easily fabricated by electrospinning. Titanium dioxide (TiO2) nanopowder with an anatase structure was applied to the nanofilters as it has the highest photocatalytic activity among the existing photocatalysts. PVA nanofilters fabricated by electrospinning could still be dissolved in water by hydrolysis. Therefore, heat treatment was performed to make the nanofilters stable, thereby forming C=O bonds by keto-enol tautomerization. Structural changes in the PVA nanofilter before and after heat treatment were investigated by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) analysis. As the TiO2 concentration increased, the fiber diameter of the PVA nanofilter decreased and a homogeneous fiber was obtained. The filtration efficiency and pressure drop also improved significantly, compared to those of the PVA-only nanofilter. Moreover, we observed eco-friendly decomposition of the PVA/TiO2 nanofilter into water and carbon dioxide by a photocatalytic reaction under UV irradiation. Copyright © 2020 American Chemical Society.Parameters comprising the relative position and relative rotation of molecules can be evaluated when the principal axes of inertia of the entities in a supramolecular association are employed as reference. Such information applies to the characterization and identification of experimental and theoretical nonbonded systems. The parameters are relevant to geometric comparison (for theory and experiment) and, for instance, to monitoring structures by theoretical simulations. This work introduces a software developed to obtain such parameters through the discussion of some intriguing host-guest systems, the ferrocene/cucurbit[7]uril and ferrocenyl azide/β-cyclodextrin. The ideas within this contribution naturally apply to the study of other nonbonded associations beyond host-guest chemistry. A modified version of the software discussed herein serves to obtain user-defined spatial arrangements for two nonbonded entities. Therefore, with a given geometry, for instance, from X-ray data, the parameters can be derived, and with the parameters, from a theoretical perspective, a spatial arrangement can be obtained. Copyright © 2020 American Chemical Society.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). Finally, the gas-sensing performance of ST/reduced graphene oxide (RGO) and PDAC/RGO sensors fabricated via LbL atop of gold interdigitated microelectrodes is evaluated at different relative humidity levels and in different concentrations of ammonia, ethanol, and acetone. In comparison to the PDAC/RGO sensor, the ones containing ST are much more sensitive, especially when operating in a high-relative-humidity environment. An array comprising these chemical sensors provides unique electrical fingerprints for each of the investigated analytes and is capable of discriminating and quantifying them in a wide range of concentrations, from 10 to 1000 ppm. Copyright © 2020 American Chemical Society.Iron pentacarbonyl (Fe(CO)5) is a versatile material that is utilized as an inhibitor of flame, shows soot suppressibility, and is used as a precursor for focused electron-beam-induced deposition (FEBID). this website X-ray absorption near-edge structure (XANES) of the K edge, which is a powerful technique for monitoring the oxidation states and coordination environment of metal sites, can be used to gain insight into Fe(CO)5-related reaction mechanisms in in situ experiments. We use a finite difference method (FDM) and molecular-orbital-based time-dependent density functional theory (TDDFT) calculations to clarify the Fe K-edge XANES features of Fe(CO)5. The two pre-edge peaks P1 and P2 are mainly the Fe(1s) → Fe-C(σ*) and Fe(1s) → Fe-C(π*) transitions, respectively. When the geometry transformed from D 3h to C 4v symmetry, a ∼30% decrease of the pre-edge P2 intensity was observed in the simulated spectra. This implies that the π bonding of Fe and CO is sensitive to changes in geometry. The following rising edge and white line regions are assigned to the Fe(1s) → Fe(4p)(mixing C(2p)) transitions. Our results may provide useful information to interpret XANES spectra variations of in situ reactions of metal-CO or similar compounds with π acceptor ligandlike metal-CN complexes. Copyright © 2020 American Chemical Society.Environmentally benign mechanochemistry-assisted high-yielding synthesis of fluorescein-phenylalaninol (FPA) conjugates as a Schiff base receptor is reported herein. This newly synthesized fluorescent probe is found to be most exciting and efficient because of its simultaneous detection and removal of mercury ions (Hg2+) in aqueous medium and industrial effluents through precipitate formation. The receptor successfully worked as a chemosensor in selectively sensing the Hg2+ ion through the rapid transition from yellow to pink in the colorimetric as well as quenching of fluorescence intensity in the fluorometric assay. The removal of mercury ions was confirmed by the inductively coupled plasma analysis of the supernatant. The lower detection limit of Hg2+ ions for the receptor FPA is 1.65 and 0.34 μM as determined through absorption and fluorescence spectroscopic methods, respectively. The high removal efficiency (∼98%) of the mercury ions is promising and could be achieved via the formation of the complex in a 11 stoichiometric ratio of receptor to Hg2+ ions.