Gyroid-Nanostructured All-Solid Polymer Films Combining High H+ Conductivity with Low H2 Permeability.

Gyroid-nanostructured all-solid polymer films with exceedingly high proton conductivity and low H2 gas permeability have been created via crosslinking polymerization of mixtures of a zwitterionic amphiphilic monomer and a polymerizable imide-type acid that co-organize into bicontinuous cubic liquid-crystalline phases. The gyroid nanostructures are visualized by reconstructing a 3D electron map from the synchrotron X-ray diffraction patterns. These films exhibit high proton conductivity of the order of 10-1 S cm-1 and extremely low H2 gas permeability of the order of 10-15 mol m m-2 s-1 Pa-1 . These properties can be ascribed to the presence of the ionic liquid-like layer along the gyroid minimal surface. Since these two characteristics are required for improving the performance of proton-exchange membrane fuel cells, the present membrane design represents a promising strategy for the development of advanced devices, pertinent to establishing sustainable energy sources.

Thiol-functionalized magnetic carbon nanotubes for magnetic micro-solid phase extraction of sulfonamide antibiotics from milks and commercial chicken meat products.

Thiol-functionalized magnetic carbon nanotubes (TMCNTs) were employed as the sorbent in the magnetic micro-solid phase extraction (M-µ-SPE) of sulfonamide antibiotics (SAs) in water, milks and chicken meat products prior to high performance liquid chromatography-diode array detector (HPLC-DAD) analysis. The synthesized sorbent was characterized by several spectroscopic techniques. Optimum conditions were: 20 mg of TMCNTs at pH 4, 2 min extraction time, 10% addition of salt and 30 mL of sample volume. Under the optimized TMCNTs-M-µ-SPE and HPLC-DAD conditions, the method showed good linearity in the range of 0.1-500 µg L-1 (r2 ≥ 0.9950), low limits of detection (0.02-1.5 µg L-1), good analytes recovery (80.7-116.2%) and acceptable RSDs (0.3-7.7%, n = 15). The method was applied to tap water (1), milks (15) and commercial chicken meat products (35), SAs were detected in five chicken meat samples (3.0-25.7 µg L-1). The method is critically compared to those reported in the literature.

Dispersive liquid-liquid microextraction combined with dispersive solid-phase extraction for gas chromatography with mass spectrometry determination of polycyclic aromatic hydrocarbons in aqueous matrices.

This study describes a dispersive liquid-liquid microextraction combined with dispersive solid-phase extraction method based on phenyl-functionalized magnetic sorbent for the preconcentration of polycyclic aromatic hydrocarbons from environmental water, sugarcane juice, and tea samples prior to gas chromatography with mass spectrometry analysis. Several important parameters affecting the extraction efficiency were investigated thoroughly, including the mass of sorbent, type and volume of extraction solvent, extraction time, type of desorption solvent, desorption time, type and amount of salt-induced demulsifier, and sample volume. Under the optimized extraction and gas chromatography-mass spectrometric conditions, the method revealed good linearity (10-100000 ng/L) with coefficient of determination (R2 ) of ≥0.9951, low limits of detection (3-16 ng/L), high enrichment factors (61-239), and satisfactory analyte recoveries (86.3-109.1%) with the relative standard deviations < 10% (n = 5). The entire sample preparation procedure was simple, rapid and can be accomplished within 10 min. This method was applied (after pretreatment) to 30 selected samples, and the presence of studied analytes was quantified in 17 samples.

Low Temperature Synthesized H2Ti3O7 Nanotubes with a High CO2 Adsorption Property by Amine Modification.

Carbon dioxide (CO2) capture and storage (CCS) technologies have been attracting attention in terms of tackling with global warming. To date, various CO2 capture technologies including solvents, membranes, cryogenics, and solid adsorbents have been proposed. Currently, a liquid adsorption method for CO2 using amine solution (monoethanolamine) has been practically used. However, this liquid phase CO2 adsorption process requires heat regeneration, and it can cause many problems such as corrosion of equipment and degradation of the solution. Meanwhile, solid adsorption methods using porous materials are more advantageous over the liquid method at these points. In this context, we here evaluated if hydrogen titanate (H2Ti3O7) nanotubes and the surface modification effectively capture CO2. For this aim, we first developed a facile synthesis method of H2Ti3O7 nanotubes different from any conventional methods. Briefly, they were converted from the precursors-amorphous TiO2 nanoparticles at room temperature (25 °C). We then determined the outer and the inner diameters of the H2Ti3O7 nanotubes as 3.0 and 0.7 nm, respectively. It revealed that both values were much smaller than the reported ones; thus the specific surface area showed the highest value (735 m2/g). Next, the outer surface of H2Ti3O7 nanotubes was modified using ethylenediamine to examine if CO2 adsorption capacity increases. The ethylendiamine-modified H2Ti3O7 nanotubes showed a higher CO2 adsorption capacity (50 cm3/g at 0 °C, 100 kPa). We finally concluded that the higher CO2 adsorption capacity could be explained, not only by the high specific surface area of the nanotubes but also by tripartite hydrogen bonding interactions among amines, CO2, and OH groups on the surface of H2Ti3O7.

Organosilica Membrane with Ionic Liquid Properties for Separation of Toluene/H2 Mixture.

In this study, we present a new concept in chemically stabilized ionic liquid membranes: an ionic liquid organosilica (ILOS) membrane, which is an organosilica membrane with ionic liquid-like properties. A silylated ionic liquid was used as a precursor for synthesis. The permselectivity, permeation mechanism, and stability of the membrane in the H2/toluene binary system were then compared with a supported ionic liquid membrane. The membrane showed a superior separation factor of toluene/H2 (>17,000) in a binary mixture system based on a solution-diffusion mechanism with improved durability over the supported ionic liquid membrane.

Separator Decoration with Cobalt/Nitrogen Codoped Carbon for Highly Efficient Polysulfide Confinement in Lithium-Sulfur Batteries.

A macro-/mesoporous Co-N-C-decorated separator is proposed to confine and reutilize migrating polysulfides. Endowed with a desirable structure and synchronous lithio- and sulfiphilic chemistry, the macro-/mesoporous Co-N-C interface manipulates large polysulfide adsorption uptake, enabling good polysulfide adsorption kinetics, reversible electrocatalysis toward redox of anchored polysulfides, and facile charge transport. It significantly boosts the performance of a simple 70 wt % S/MWCNTs (MWCNTs=multi-walled carbon nanotubes) cathode, achieving high initial capacities (e.g., 1406 mAh g-1 at 0.2C, 1203 mAh g-1 at 1C), nearly 100 % Coulombic efficiencies, and high reversible capacities after cycle tests (e.g., 828.4 mAh g-1 at 1C after 100 cycles) at both low and high current rates. These results demonstrate that decorating separator with macro-/mesoporous Co-N-C paves a feasible way for developing advanced Li-S batteries.

Real-Time Observation of Hydrogen Peroxide Transport through the Oil Phase in a W/O/W Double Emulsion with Chemiluminescence Emission.

The evaluation of the transport rates of hydrophilic substances is important in agricultural and pharmaceutical chemistry and in the cosmetics and food-processing industries. Although there are some estimation methods focusing on the diffusion of the substances through the oil phase of the W/O/W core-shell double emulsions (oil microcapsules), all of them take several hours or days. This long-time measurement has a risk of rupture of the oil microcapsules, which causes significant errors. If it were possible to measure the transport rate of substances in the oil phase of the oil microcapsules in real time, the risk of rupture could be reduced. Here, we propose a new estimation method for the transport rates of hydrogen peroxide (H2O2) in the oil phase of an oil microcapsule for real-time estimation by means of chemiluminescence (CL) emission of the luminol reaction. We theoretically give the relationship among the CL emission intensity, diffusion coefficient, microcapsule size, and experimental time and successfully estimate the diffusion coefficient of H2O2 in the oil phase of the oil microcapsule from the experimental data. Moreover, we discuss the dependence of the permeation of H2O2 through the oil phase on the concentration of the oil-soluble surfactant; the difference in the permeation rate is likely to be attributed not to the diffusion coefficient but to the partition coefficient of H2O2 in the oil microcapsule.

Nanosheet Formation in Hyperswollen Lyotropic Lamellar Phases.

Nanosheets (∼1 nm) are formed using a nonionic hyperswollen lyotropic lamellar phase as a template. The accumulation and reaction of ingredients in the highly separated (several hundred nm) bilayers in the hyperswollen lyotropic lamellar phase should result in very thin nanosheets. This method could be applied to the synthesis of a wide variety of two-dimensional organic and inorganic materials.