Ionic Liquid Stabilizes Olefin Facilitated Transport Membranes Against Reduction.

Separation of olefins from their paraffin analogs relies on energy-intensive cryogenic distillation. Facilitated transport-based membranes that reversibly and selectively bind olefins, but not paraffins, could save considerable amounts of energy. However, the chemical instability of the silver ion olefin-binding carriers in such membranes has been a longstanding roadblock for this approach. We discovered long-term carrier stability against extended exposure to hydrogen, a common contaminant in such streams. Based on UV/Vis absorption and Raman spectroscopy, along with XRD analysis results, certain ionic liquids solubilize silver ions, and anion aggregates surrounding the silver ion carriers greatly attenuate their reduction by hydrogen. Here, we report the stability of olefin/paraffin separation properties under continuous exposure to high pressure hydrogen, which addresses a critical technical roadblock in membrane-based olefin/paraffin separation.

Prediction Model for Dry Eye Syndrome Incidence Rate Using Air Pollutants and Meteorological Factors in South Korea: Analysis of Sub-Region Deviations.

Here, we develop a dry eye syndrome (DES) incidence rate prediction model using air pollutants (PM10, NO2, SO2, O3, and CO), meteorological factors (temperature, humidity, and wind speed), population rate, and clinical data for South Korea. The prediction model is well fitted to the incidence rate (R2 = 0.9443 and 0.9388, p < 2.2 × 10-16). To analyze regional deviations, we classify outpatient data, air pollutant, and meteorological factors in 16 administrative districts (seven metropolitan areas and nine states). Our results confirm NO2 and relative humidity are the factors impacting regional deviations in the prediction model.

Sustainable Low-Temperature Hydrogen Production from Lignocellulosic Biomass Passing through Formic Acid: Combination of Biomass Hydrolysis/Oxidation and Formic Acid Dehydrogenation.

Hydrogen production from renewable resources, such as lignocellulosic biomass, is highly desired, under the most sustainable and mildest reaction conditions. In this study, a new sustainable three-step process for the production of hydrogen has been proposed. In the first step, a crude formic acid (CF) solution, which included typical reaction byproducts, in particular, acetic acid, levulinic acid, saccharides, 5-hydroxymethylfurfural, furfural, and lignin, was obtained through the combined hydrolysis/oxidation of the biomass, in the presence of diluted sulfuric acid/hydrogen peroxide, as homogeneous catalysts. In the second one, the distilled formic acid (DF) solution was obtained by distillation of the CF solution, for example, by isolating liquid byproducts, or the lignin-free CF (LCF) solution was recovered by CF filtration for the elimination of only solid lignin particles. In the final step, hydrogen was produced from the DF or LCF solutions through formic acid dehydrogenation over Pd supported on amine-functionalized mesoporous silica catalysts, in the presence of sodium formate, as an additive. The clean hydrogen, which is produced from biomass passing through formic acid, could be applied as an energy source of fuel cells. This new hydrogen production process is smart, allowing the hydrogen production with mild reaction conditions, eventually starting from different lignocellulosic feedstocks, and it could be integrated within the existing hydrothermal technology for levulinic acid production, which has been already recognized as efficient and sustainable. In addition to the production of hydrogen as an energy source of fuel cells, formic acid derived from biomass could be utilized as a platform chemical for chemical, agricultural, textile, leather, pharmaceutical, and rubber industries.

Development of a Conjunctivitis Outpatient Rate Prediction Model Incorporating Ambient Ozone and Meteorological Factors in South Korea.

Ozone (O3) is a commonly known air pollutant that causes adverse health effects. This study developed a multi-level prediction model for conjunctivitis in outpatients due to exposure to O3 by using 3 years of ambient O3 data, meteorological data, and hospital data in Seoul, South Korea. We confirmed that the rate of conjunctivitis in outpatients (conjunctivitis outpatient rate) was highly correlated with O3 (R 2 = 0.49), temperature (R 2 = 0.72), and relative humidity (R 2 = 0.29). A multi-level regression model for the conjunctivitis outpatient rate was well-developed, on the basis of sex and age, by adding statistical factors. This model will contribute to the prediction of conjunctivitis outpatient rate for each sex and age, using O3 and meteorological data.

Genomic and probiotic characterization of SJP-SNU strain of Pichia kudriavzevii.

The yeast strain SJP-SNU was investigated as a probiotic and was characterized with respect to growth temperature, bile salt resistance, hydrogen sulfide reducing activity, intestinal survival ability and chicken embryo pathogenicity. In addition, we determined the complete genomic and mitochondrial sequences of SJP-SNU and conducted comparative genomics analyses. SJP-SNU grew rapidly at 37 °C and formed colonies on MacConkey agar containing bile salt. SJP-SNU reduced hydrogen sulfide produced by Salmonella serotype Enteritidis and, after being fed to 4-week-old chickens, could be isolated from cecal feces. SJP-SNU did not cause mortality in 10-day-old chicken embryos. From 13 initial contigs, 11 were finally assembled and represented 10 chromosomal sequences and 1 mitochondrial DNA sequence. Comparative genomic analyses revealed that SJP-SNU was a strain of Pichia kudriavzevii. Although SJP-SNU possesses pathogenicity-related genes, they showed very low amino acid sequence identities to those of Candida albicans. Furthermore, SJP-SNU possessed useful genes, such as phytases and cellulase. Thus, SJP-SNU is a useful yeast possessing the basic traits of a probiotic, and further studies to demonstrate its efficacy as a probiotic in the future may be warranted.

Reinforced PEI/PVdF Multicore-Shell Structure Composite Membranes by Phase Prediction on a Ternary Solution.

To construct a polyetherimide (PEI)-reinforced polyvinylidene fluoride (PVdF) composite membrane with multicore-shell structure, a ternary solution was prepared and electrospun by single-nozzle electrospinning. A theoretical prediction was made for the feasibility of complete distinction of two phases. The diameters of the membrane fibers and the PEI multi-core fibrils varied with the PEI ratio and the spinning time, respectively. The tensile strength and modulus were improved to 48 MPa and 1.5 GPa, respectively. The shrinkage of the membrane was only 6.6% at 180 °C, at which temperature the commercial PE separator melted down. The reinforcement in mechanical and thermal properties is associated with multiple PEI nanofibrils oriented along the fiber axis. Indeed, the unique morphology of self-assembled multicore-shell fibers plays an important role in their properties. All in all, PEI/PVdF membranes are appropriate for a lithium-ion battery application due to their high mechanical strength, excellent thermal stability, and controllable textural properties.

Multicore-shell nanofiber architecture of polyimide/polyvinylidene fluoride blend for thermal and long-term stability of lithium ion battery separator.

Li-ion battery, separator, multicoreshell structure, thermal stability, long-term stability. A nanofibrous membrane with multiple cores of polyimide (PI) in the shell of polyvinylidene fluoride (PVdF) was prepared using a facile one-pot electrospinning technique with a single nozzle. Unique multicore-shell (MCS) structure of the electrospun composite fibers was obtained, which resulted from electrospinning a phase-separated polymer composite solution. Multiple PI core fibrils with high molecular orientation were well-embedded across the cross-section and contributed remarkable thermal stabilities to the MCS membrane. Thus, no outbreaks were found in its dimension and ionic resistance up to 200 and 250 °C, respectively. Moreover, the MCS membrane (at ~200 °C), as a lithium ion battery (LIB) separator, showed superior thermal and electrochemical stabilities compared with a widely used commercial separator (~120 °C). The average capacity decay rate of LIB for 500 cycles was calculated to be approximately 0.030 mAh/g/cycle. This value demonstrated exceptional long-term stability compared with commercial LIBs and with two other types (single core-shell and co-electrospun separators incorporating with functionalized TiO2) of PI/PVdF composite separators. The proper architecture and synergy effects of multiple PI nanofibrils as a thermally stable polymer in the PVdF shell as electrolyte compatible polymers are responsible for the superior thermal performance and long-term stability of the LIB.

Comprehensive stabilization mechanism of electron-beam irradiated polyacrylonitrile fibers to shorten the conventional thermal treatment.

An electron beam was irradiated on polyacrylonitrile (PAN) fibers prior to thermal stabilization. The electron-beam irradiation effectively shortened the thermal stabilization process by one fourth compared with the conventional thermal stabilization process. A comprehensive mechanistic study was conducted regarding this shortening of the thermal stabilization by electron-beam irradiation. Various species of chain radicals were produced in PAN fibers by electron-beam irradiation and existed for a relatively long duration, as observed by electron spin resonance spectroscopy. Subsequently, these radicals were gradually oxidized to peroxy radicals in the presence of oxygen under storage or heating. We found that these peroxy radicals (CO) enabled such an effective shortcut of thermal stabilization by acting as intermolecular cross-linking and partial aromatization points in the low temperature range (100-130 °C) and as earlier initiation seeds of successive cyclization reactions in the next temperature range (>130-140 °C) of thermal stabilization. Finally, even at a low irradiation dose (200 kGy), followed by a short heat treatment (230 °C for 30 min), the PAN fibers were sufficiently stabilized to produce carbon fibers with tensile strength and modulus of 2.3 and 216 GPa, respectively, after carbonization.

Facile synthesis of mesoporous silica and titania supraparticles by a meniscus templating route on a superhydrophobic surface and their application to adsorbents.

Mesoporous silica and titania supraparticles with controllable pore size, particle size, and macroscopic morphology were readily synthesized by a novel synthetic pathway using meniscus templating on a superhydrophobic surface, which is much simpler than well-known emulsion systems. Moreover, we first report that despite the very large radius of droplet curvature on a millimeter scale, supraparticles kept the round cap morphology due to addition of sucrose as a shape preserver as well as a pore-forming agent. In addition, mesoporous silica and titania supraparticles provided good adsorption performance for Acid Blue 25 and Cr(VI), and were easily separated from the solution by using a scoop net after adsorption tests.

Two-in-one fuel combining sugar cane with low rank coal and its CO2 reduction effects in pulverized-coal power plants.

Coal-fired power plants are facing to two major independent problems, namely, the burden to reduce CO(2) emission to comply with renewable portfolio standard (RPS) and cap-and-trade system, and the need to use low-rank coal due to the instability of high-rank coal supply. To address such unresolved issues, integrated gasification combined cycle (IGCC) with carbon capture and storage (CCS) has been suggested, and low rank coal has been upgraded by high-pressure and high-temperature processes. However, IGCC incurs huge construction costs, and the coal upgrading processes require fossil-fuel-derived additives and harsh operation condition. Here, we first show a hybrid coal that can solve these two problems simultaneously while using existing power plants. Hybrid coal is defined as a two-in-one fuel combining low rank coal with a sugar cane-derived bioliquid, such as molasses and sugar cane juice, by bioliquid diffusion into coal intrapores and precarbonization of the bioliquid. Unlike the simple blend of biomass and coal showing dual combustion behavior, hybrid coal provided a single coal combustion pattern. If hybrid coal (biomass/coal ratio = 28 wt %) is used as a fuel for 500 MW power generation, the net CO(2) emission is 21.2-33.1% and 12.5-25.7% lower than those for low rank coal and designed coal, and the required coal supply can be reduced by 33% compared with low rank coal. Considering high oil prices and time required before a stable renewable energy supply can be established, hybrid coal could be recognized as an innovative low-carbon-emission energy technology that can bridge the gulf between fossil fuels and renewable energy, because various water-soluble biomass could be used as an additive for hybrid coal through proper modification of preparation conditions.