查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryOver the years, a reduced upper limit on sulfur content in marine-vehicle fuel has created a situation where a major diversion of sulfur into bitumen will be noticeable in the near future. In addition to the naturally occurring sulfur compounds in bitumen, sulfur is known as a promising admixture for the bitumen matrix. Despite the hydrophobic nature of elemental sulfur, which is commercially used as a modifier or extender in asphalt mixtures, the moisture susceptibility of sulfurized bitumen is one of the concerns challenging the use of sulfur in bitumen. In this study, we used laboratory experiments to examine how the effect of moisture conditioning varies between low-sulfur bitumen and high–sulfur bitumen. We also used molecular modeling in a framework of density functional theory (DFT) to gain insights into the molecular mechanisms by which a hydrophobic substance (elemental sulfur) acts as a hydrophile to attract water molecules and increase the moisture susceptibility of bitumen. The results show that high–sulfur bitumen has significantly more strain accumulation and shear thinning when exposed to water for an extended period. Based on our molecular-level analysis geared toward a DFT approach, the affinity of polymeric chains of sulfur to water could be a driving force for the moisture susceptibility of sulfurized bitumen. The presence of polymeric chains of sulfur, even at ambient temperature, can be attributed to that portion of polysulfides formed at high temperatures that remain in the matrix after dropping the temperature. Another mechanism proposed is the thermal decomposition of polysulfides upon heating, leading to the formation of thiols (RS-H), which can easily interact with water molecules. Considering the higher concentration of S[dbnd]O bonds in sulfurized bitumen, a part of the moisture susceptibility could also be attributed to those sulfur compounds that have been functionalized with hydrophilic groups, such as sulfonate, sulfoxide, or other functional groups containing oxygen. The high concentrations of sulfoxide group (S[dbnd]O), particularly in aged bitumen, and their ability to set up H-bonding interactions, make them potential candidates for effective interactions with water molecules.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryTo prepare g-C3N4 for photocatalytic tetracycline (TC) removal, KCl was employed to mix with or cover the top of the precursors, namely, melamine and urea. The mixing of KCl with the precursor will result in the incorporation of KCl within the layer structure of g-C3N4, whereas KCl covering the top might not have such an effect. Different precursor ratios contributed to the formation of heptazine-rich or triazine-rich units in the g-C3N4 structure. Melamine applied alone as a precursor will undergo a phase transformation into melam and triazine-rich g-C3N4, whereas with the addition of urea, the mixture will polymerize to form melem and heptazine-rich g-C3N4. The KCl-incorporated, heptazine-rich g-C3N4 (KCN80m) exhibited an improved photocatalytic activity for TC removal (greater than 80% during a 120-min period for 50 mL of a 20-ppm TC solution). The enhanced activity can be attributed to the improved charge separation through an electron and hole transfer through the K+ and Cl- sites, respectively; the formation of a nanojunction between the triazine and heptazine units of g-C3N4; an increased number of photoexcited electrons, indicated by the electron paramagnetic resonance spectroscopy results. We varied the mixing conditions of KCl and precursor ratio to synthesize different KCl-incorporated heptazine-rich g-C3N4 samples for effective removal of TC from water through photocatalysis.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryThe development of photocatalysts for efficient photodegradation of emerging water pollutants is a subject of global concern in recent years. In this study, the photophysical properties of TiO2 were modified by doping with different concentrations of boron (B-TiO2) and nitrogen (N-TiO2) by following a sol–gel route of synthesis. The type and concentration of dopants were optimized to achieve maximum degradation of acetaminophen (ACT) and monocrotophos (MCP) in aqueous solutions. UV DRS analysis shows that the bandgap of TiO2 (3.2 eV) reduced up to 2.96 and 2.27 eV in B-TiO2 and N-TiO2 samples, respectively. The presence of dopants inside the crystal lattice of doped TiO2 was confirmed with X-ray diffraction (XRD), Micro Raman, Fourier Transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The XRD data confirmed that the presence of these dopants promotes the rutile phase transformation in TiO2 to various extents. The doping of B decreased the surface area and pore volume of TiO2, whereas N doping had increased these properties. The XPS spectra showed the formation of Ti-O-B and Ti-O-N type linkage, indicating the presence of interstitial B and substitutional N atoms in TiO2 crystal lattice. The B doped samples exhibit more enhancement in photodegradation efficiency as compared to N doped samples. Under optimized conditions, 5% B-TiO2 showed 95% and 71% degradation of ACT and MCP, respectively. The degradation pathway for both ACT and MCP involving their intermediates was discussed through Mass spectrometry analysis. The cost-effectiveness of the most efficient doped catalysts and commercial catalysts were compared with the ACER tool and turnover frequency.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryWe systematically investigated the strain-induced carrier mobility of two representative n-type and p-type organic semiconductors, 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) and N,N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8), in order to understand the relationship between the carrier mobility and intermolecular packing configurations. The applied strain to organic semiconductors changes the intermolecular packing configurations, such as the π–π stacking distance and π–π overlap extent between adjacent π-conjugated molecules. In particular, the in-phase and out-of-phase π–π orbital interactions cause carrier mobility variations and energy level splitting by constructive/bonding and destructive/antibonding interactions between adjacent π-conjugated molecules. Our results demonstrate periodic changes of the strain-induced carrier mobility with respect to the π–π stacking distance and π–π overlap type, respectively. Furthermore, we propose that the periodic behaviors of carrier mobility can be attributed to the alternating phase changes of the molecular orbital interactions under applied strain. Based on the understanding of the intermolecular interactions and the structure–property relationships, we can provide a strain path for optimal carrier mobility modulation and the development of high-performance organic electronic devices.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryThe rapid emergence of multidrug-resistant microbes has turned into the main threat to public health worldwide. The preparation and application of nanomaterial-based antimicrobials have increased to address this problem with great significance. This study has investigated the bio-fabrication of polycrystalline Ag-NCs using BCE as a reducer and stabilizer under microwave irradiation. Ag-NCs formations were optimized using varying concentrations of BCE and silver acetate. The XRD confirmed the incidence of phases of nanostructured crystals of Ag/AgO/AgCl. The average crystallite sizes were calculated to be 22.19, 36.65, and 36.65 nm for Ag, AgO, and AgCl, respectively. SERS spectra revealed the vibrational modes of the Ag and Ag-O stretch bands. FTIR spectra have indicated the incidence of chemical fingerprints for Ag-NCs and BCE biomolecules. SEM and HR-TEM micrographs exhibited the almost spherical to the oval shape of ～50 nm. SAED pattern attested to silver crystallinity in agreement with XRD analysis. The MIC values of the Ag-NCs against Escherichia coli, Staphylococcus aureus, Aspergillus brasiliensis, and Rhizopus stolonifer were observed to be 120, 60, 200, and 100 μg/ml, respectively. This study has demonstrated the facile method to prepare polycrystalline Ag-NCs with appropriate structural and morphological characteristics for antimicrobial applications.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryIntestinal organoids are emerging tools in intestinal disease modeling and regeneration. Matrigel, a basement membrane matrix extracted from mouse sarcoma, is the gold standard material for intestinal organoid culture. Yet, the tumor origin of this matrix does not effectively provide organoids with native intestine-like microenvironments. To overcome this limitation, we demonstrate a decellularized small intestine-derived hydrogel reinforced with three extracellular matrix (ECM) proteins that are essential for intestinal development. To identify optimal conditions for intestinal organoid culture, we optimized the concentrations of the ECM hydrogel derived from decellularized intestine and three ECM proteins. The intestinal organoids grown in the established ECM hydrogels have shown similarity to those grown in Matrigel in terms of organoid forming efficiency, size, and gene expression patterns of intestine-specific markers. Our intestine-mimetic hydrogel could increase the feasibility of intestinal organoids for more clinically relevant applications in disease modeling and regenerative medicine.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryWaterborne epoxy (WEP) resins are of great significance as multifunctional properties recently. Nevertheless, their curing process, which involves the formation of numerous micro-pores via water evaporation, has limited applications in the industrial utilizations. In this work, we have synthesized and enhanced the water-dispersible Zirconium phosphate decorated graphene oxide (ZrP@GO) nanocomposites through a one-step preparation method of graphene oxide (GO) sheets decorated with ZrP nanoparticles, and the as-prepared ZrP@GO nanocomposites were introduced as nanofillers for WEP system in order to enhance its multifunctional properties. The as-prepared GO, ZrP, and ZrP@GO hybrids were scrutinized by XRD, XPS, Raman, TGA, and its morphology study were investigated with the assistance of AFM, TEM, and FESEM. The anticorrosive properties were analyzed using natural salt spray tests (NSS). The ZrP@GO mixed WEP coatings exhibit better protection towards corrosion when compared to WEP/GO and WEP/ZrP coatings. Also, the excellent mechanical and thermal properties were achieved with the incorporation of ZrP@GO hybrids with the WEP system. The better performance of ZrP@GO was achieved through enhanced dispersion, exfoliation, and the outstanding shielding effect of the smectic aligned layers of ZrP@GO hybrids. Besides, a finite element model proposed through this research to predict the tensile behaviors are good in agreement with the measured vales.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryDual-layer composite membranes composed of Pebax 1657, different 1-Ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF4]) contents and Polyethersulfone (PES) were fabricated by co-casting method, to investigate CO2/light gases separation, due to the high affinity of CO2 to Pebax and the ionic liquid (IL). Gas permeation test, which was performed at 25 °C and pressure range of 4–8 bar, indicated remarkable increment in CO2, CH4 and N2 permeance through membranes, especially CO2, as well as ideal CO2/CH4 and CO2/N2 selectivities, with IL increment. At 6 bar, CO2 permeance increased 152.97% meanwhile, at 8 bar, CO2/CH4 and CO2/N2 selectivities increased 59.22% and 28.64%, respectively, in the membrane containing 20 wt. % IL, which is the optimum IL content. In addition, CO2 permeance and selectivity increased with pressure. FTIR, XRD, DSC, SEM, dynamic frequency sweep, contact angle and tensile test results revealed the formation of defect-free dense Pebax/IL top-layer on porous PES sub-layer. IL addition led to formation of new bonds between the IL and Pebax which cause changes in the chain packing and crystallinity of Pebax and fabrication of more amorphous top-layer and more porous sub-layer. These results are confirmed by decrement in the mechanical properties of Pebax/IL casting solutions and composite membranes, by IL increment.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryCommercial V-W-Ti catalysts were modified with Cu and different contents of Ce to remove slip ammonia and remaining nitrogen oxide from the end stage of SCR technology. The activities of NH3 oxidation by O2 (NH3-SCO) and NO reduction by NH3 (NH3-SCR) of these catalysts were examined from 150 to 400 ℃. The consequences indicated that the addition of Ce and Cu could considerably enhance NH3 oxidation and NO reduction capacity of the catalysts and Ce was conducive to reduce the detrimental effects of H2O and SO2. The characterization tests indicated that the surface active oxygen increased because of the interaction between V, Cu and Ce. Moreover, the loaded Ce and Cu contributed to enhance the surface acidity and redox property of SCR catalysts.
查看更多>>摘要：? 2021Chemical mechanical polishing (CMP), a wafer surface planarization method, is critical in the semiconductor industry because uniform and scratch-free processing is required for a highly integrated circuit on the wafer surface. Thus, the prediction of aggregated particle size during CMP helps achieve stable and precise processing during experimental circumstances. Herein, silica nanoparticle aggregation simulation during CMP process-based Quadrature Method of Moments (QMOM) was first described using ANSYS Fluent as a computational fluid dynamics (CFD) tool. Experiments were also implemented in a 10,000 class cleanroom using a CMP polisher actually used in the semiconductor industry. Moreover, a comparison of experimental particle size measured through zeta-potential and particle size analyzer and simulated Sauter mean diameter (D32) showed that the experimental data agreed well with the simulation results.
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