查看更多>>摘要：Membrane fouling by the high protein concentrations used in the biopharmaceutical industry remains poorly understood. In this study, feed concentrations of up to 10,000 ppm of bovine serum albumin (BSA) were investigated with three polymeric membranes, two of which had the same molecular weight cut-off (namely, PES100 and PSF100), and two were of the same membrane material (namely, PES100 and PES10). A crossflow ultrafiltration (UF) setup equipped with electrical impedance spectroscopy (EIS) was used. Results indicate that fouling was predominantly external for all cases, except for the PES100 mem-brane (i.e., most porous) at 10,000 ppm of BSA, whereby fouling was internal which led to the greatest flux decline. For 10,000 ppm of BSA, (i) for the PES100 and PSF100 membranes, the Nyquist plots shifted to the left initially, then to the right as the BSA deposition started, but (ii) for the tighter PES10 mem-brane, the shifts kept going leftwards due to NaCl accumulation out-pacing BSA build-up. The main take-away for filtering feeds with high BSA concentrations is that higher steady-state flux could be achieved by averting internal fouling, either through using membranes with dense internal structures or lower MWCO.
查看更多>>摘要：Diverse methods have been developed for the synthesis of active nanocatalysts involving various heterogeneous catalytic reactions. Thus far, numerous trial-and-error runs have been done to find the effective and practical ways. In the present work, the All-In-One (AIO) reactor system with a well-designed synthesis program, now in pilot stage, was first exploited as a reliable synthesis tool to find the optimum conditions for the production of Ni nanocatalysts. Using an activated charcoal support, active Ni nanoparticles of 7.8-11.8 nm (labeled A001-A007 in the program) were produced. These were achieved using a melt-impregnation process, which was controlled by variations in the applied gas (N2 and H2) and temperature (400 degrees C, 450 degrees C, and 500 degrees C) used as critical factors in the calcination step. Based on the optimization of the reaction sequence, each Ni nanocatalyst could be prepared within 5 h and 22 min. In particular, the optimum Ni nanocatalyst (A006) with the smallest particle size (7.8 nm), prepared under H2 flow at 400 degrees C, exhibits the highest catalytic activity (0.748 mmol4-NP center dot gcat1 center dot s1) among the Ni catalysts for 4-nitrophenol (4-NP) reduction to 4-aminophenol (4-AP). This activity is much higher than that of conventional supported Ni nanocatalysts (0.551 mmol4-NP center dot gcat 1 center dot s1) produced using the wetness method. (c) 2021 The Author(s). Published by Elsevier B.V. on behalf of The Korean Society of Industrial and Engineering Chemistry. This is an open access article under the CC BY-NC-ND license
Ko, KyujinYoon, DonghyunYang, Su ChulLee, Heon Sang...
9页
查看更多>>摘要：Superhydrophobic coatings have potential applications in fouling resistance, self-cleaning, waterproofing, and drag reduction. In this work, using a facile brush-painting method for outdoor application, superhydrophobic silica coating layers were developed with high contact angle above 150 degrees, high lighttransmittance above 90 %, and strong weather resistance via three strategies: (i) hexadecyltrimethoxysilane-modified SiO2 (H-SiO2) particle agglomeration in colloidal coating solutions, and the formation of (ii) two-dimensional (2D) mud-crack patterns and (iii) three-dimensional (3D) micro-bumps. First, particle agglomeration was optimized in a mixed solution of water and ethanol with a relative permittivity of E = 48.0. Second, high transmittance and full-covered hydrophobic properties were achieved from the silica coating layers with 2D mud-crack patterns. Third, maximal contact angle of 152.6 degrees was obtained from the superhydrophobic silica coating layers consisting of heterogeneous 3D micro-bumps on the 2D mud-crack patterns. The superhydrophobic coating layers exhibited high lighttransmittance of 90.2 % and near-zero sliding angle, making them suitable for use as self-cleaning solar panels. These brush-painted superhydrophobic silica layers have potential uses in industrial coating applications by providing self-cleaning capability, weather resistance, flexibility, and transparency. (c) 2021 The Author(s). Published by Elsevier B.V. on behalf of The Korean Society of Industrial and Engineering Chemistry. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
查看更多>>摘要：Monodispersed microbubbles and microdroplets are widely used as reaction carriers in microfluidics. In this study, the generation processes of bubbles and droplets in a step-emulsification microfluidic device are compared to show the similarities and differences in the emulsification process. By changing the placement of the microdevice, the effects of buoyancy and gravity on the generation of bubbles and droplets are introduced, and the feedback mechanism of the bubble layer and the effect of droplet accumulation on the emulsification process are clarified. Finally, based on the analysis of the difference of the pinch-off of the dispersed phase between the bubble and the droplet in this configuration, the Plateau Rayleigh instability processes for the formation of bubble and droplet are revealed by using a highspeed camera system, and the reasons for the difference of the operating ranges of the gas flow rate and liquid flow rate in the dripping flow regime are explained. CO 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Fracture conformance control in reservoir can effectively improve water channel to increase crude oil displacement efficiency of subsequent waterflooding. Inspired by the remarkable underwater wet adhesion of mussel byssus, hydrogel particles which can adhere stably on the fracture rock surface in reservoir conditions could achieve long-lasting reservoir control effect. In this work, the size-controllable biomimetic functional hydrogel particles were prepared by mechanical shearing after bulk hydrogel was constructed by catechol-functionalized polyacrylamide and phenolic resin crosslinking agent. The influence of solution salinity on the aggregation and adhesion of hydrogel particles was investigated via scanning electron microscope (SEM), colloidal probe atomic force microscope (AFM) and quartz crystal microbalance with dissipation (QCM-D). The results showed that hydrogel particles maintained well-dispersed state in lowsalinity water, while exhibited significant adhesion and adsorption capacity to the silica surface in simulated reservoir salinity water. This is of great importance to the practical applications that the hydrogel particles would not show enhanced adhesion to rock surfaces until the reservoir salinity water was met, which was beneficial to the in-depth migration of hydrogel particles to achieve effective deep reservoir profile control. Furthermore, the visible micro-model was designed and applied to evaluate profile control effect of hydrogel particles, and the results showed that hydrogel particles could withstand water flushing and adhere stably to the fracture surface. The waterflooding sweep efficiency was increased remarkably from 20.3% +/- 2.0% to 38.8% +/- 2.0%. This work would help better understand the function mechanism of hydrogel particles in reservoir control and provide novel and efficient method for the practical application in enhanced oil recovery. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：In this study, Co2P/CoP hybrid nanoparticles (NPs) imbedded on the surface of core-shell metal-organic frameworks (MOFs) derived three-dimensional N, P co-doped graphitized carbon (Co2P/CoP@NPGC) are prepared via direct pyrolysis of P-containing MOF precursors. P dopant dosage is tailored to adjust active sites and crystalline phases of Co2P/CoP@NPGC. The active Co2P and CoP NPs and the synergistic effect from the Co-Nx/C and Co-P/C active sites and porous NPGC make the dominant contributions to the ORR/OER. For ORR, the half-wave potential of Co2P/CoP@NPGC-1 is 0.93 V, which is superior to that of Pt/C (E-1/2 = 0.875 V). As for OER, Co2P/CoP@NPGC-1 displays a lower overpotential (eta = 340 mV) compared to RuO2 (eta = 380 mV, at 10 mA cm(-2)). The Co2P@CoOOH heterojunction guarantees intrinsic conductivity. Furthermore, doping with N and P can modify the surface electronic structure of catalyst to lower the energy of oxygen adsorption and dissociation, which are beneficial to enhance the ORR and OER activity. Additionally, its bifunctional activity parameter (Delta E) for ORR and OER is only 0.64 V, which is lower than that of Pt/C and RuO2 (0.76 V). Therefore, this work proposes a new sight into constructing a competitive core-shell MOFs derived electrocatalyst for ORR/OER. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
Rahman, Mohammed M.Alam, M. M.Asiri, Abdullah M.Alfaifi, Sulaiman Y. M....
9页
查看更多>>摘要：High performance acute toxic methanol sensor based on hydrothermally prepared hexagonal nanodiscs (NDs) of ZnO/CdO/SnO2 (ZnCdSnO2 or ZCSO) was fabricated onto glassy carbon electrode (GCE). The characterization of ZCSO NDs in-terms of functional group analysis, binding energy evaluation, oxidation states, optical absorbance, crystallinity, structural morphology, and elemental compositions were performed by FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy, XRD, FESEM-coupled-EDS analysis respectively. The current versus concentration plot was exhibited linear on a wide range of methanol concentration (0.01 nM to 0.1 mM) clarified as linear dynamic methanol detection range (LDR). Considering the ZCSO NDs-coated surface area onto GCE over the slope of LDR, noticeable methanol sensor sensitivity (4.5475 mu A mu M-1 cm(-2)) was perceived. Besides this, a considerable lower limit (7.69 +/- 0.38 pM) of detection at signal/noise = 3 is obtained. The overall results of methanol chemical sensor were found with satisfactory and acceptable results in terms of their reproducibility, sensitivity, stability, and response-time. Additionally, the assembled ZCSO NDs-coated electrode was validated with real environmental samples and result was found good and acceptable. On considering the outcome of applicability and the way of this sensor assembling, this unique method might be a potential technique in the field of portable sensor development for the safety of environmental and healthcare fields in a broad scale. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：The development of gas sensors with high sensitivity, stability, and selectivity is vital in detecting hazardous gas leaks and monitoring air pollution. The perovskite comprises a stable chemical structure and offers multifunctional properties to act as a base for several device engineering. Specifically, perovskites possess a great potential for chemical sensors with their semiconducting nature and ease to dope with other elements to further improve gas sensing properties. In this present study, a rare-earth gadolinium orthoferrite, GdFeO3 (GFO), and Co-doped GFO were systematically investigated by evaluating their structural, morphological, electrical, and gas sensing properties. A high-temperature solid-state reaction synthesized the phase-pure compounds. The magnetic properties of Co-doped GFO significantly improved than pure GFO. The pellet-type gas sensor was fabricated, which does not need any sophisticated instrumentation such as microfabrication. When exposed to 20 ppm of NO2 gas, a GdFe0.7Co0.3O3 (GFOC3) device gave 6.86% response at 200 = C, along with a response time of 104 s and the recovery time of 97 s. Additionally, Co-doped GFO sensors showed a detectable response even at room temperature, enabling- practical applications in an ambient environment. The gas sensor revealed stable gas response characteristics even after several months. Therefore, this study elucidates that the Co-doped GFO has better gas sensing performance compared to a bare GFO and that it is highly selective towards the NO2 gas. (c) 2021 The Korean Society of Industrial and Engineering Chemistry.
Park, So JeongMaeng, Ju YoungJoo, Min HeeKang, Jun-Gill...
17页
查看更多>>摘要：Indium tin oxide (ITO) has extensively used as an electrode in diverse application areas of electrochemistry, displays, photovoltaics, and catalysts. Herein, terpyridine-modified ITO and thioterpyridinefunctionalized Au-modified ITO electrodes were prepared and evaluated for electrochemical redox behaviors and conversion rates of Ce(III)/Ce(IV) ions, and recycling recovery rates on the newly developed electrode by cyclic voltammetry and amperometry. Scanning electron microscopy, X-ray photoelectron spectroscopy, Ultraviolet photoelectron spectroscopy, X-ray diffraction crystallography, and fluorescence spectroscopy were employed for the physiochemical properties of the demonstrated electrodes before and after electrochemistry. The interfacial energy level was examined by ultraviolet photoelectron spectroscopy for ITO-Au and ITO-Au-STpy. Density functional theory calculations were performed to examine complexation between the functionalized ligand and Ce(III)/Ce(IV) ions by obtaining molecular orbital energy levels and thermodynamics. Thermal CO oxidation catalytic activity was tested for Ceelectrodeposited ITO electrode. In addition, electrochemical CO2 reduction performance was evaluated for Au-modified ITO electrode with and without thioterpyridine-functionalization. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：The lead tab serves as a terminal that collects charges generated from each electrode inside the battery and transfers it to the outside of the battery. Among the lead tabs used in the electric vehicle industry, a corrosion of aluminum (Al), chromium-coated Al (CCAl), copper (Cu), and nickel-coated Cu(NCCu) during the cycling of lithium-ion batteries is investigated. Cyclic voltammetry (CV) analysis are performed as part of the electrochemical corrosion test during battery cycle life, scanning electron microscope (SEM) for checking lead tab surface, and X-ray photoelectron spectroscopy (XPS) depth profile for a chemical analysis. By the CV results, it was inferred that the Cr and Ni coatings form a layer on the surface, and the mor-phology was visually confirmed by post CV SEM analysis. Subsequent XPS results confirm the sub-reaction related to LiPF6-carbonate electrolyte. Finally, the composition and distribution of the formed passivation layer were finally confirmed by XPS depth profile analysis. These passivation layers prevent the corrosion of the lead tab and contribute to the extension of battery life by inhibiting the dissolution of Al and Cu metals and the decomposition of the electrolyte during the charge/discharge test of LIB. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
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