查看更多>>摘要：Solketal, a fuel additive, was synthesized from the solvent-free ketalization reaction of glycerol and acetone using phosphotungstic acid (PTA) catalysts. Due to strong acidity, PTA is expected to serve as an efficient acid catalyst, however low specific surface area of bulk PTA and the deactivation, by water, denounces its acid activity leading to low solketal production. The present study demonstrates a success in increasing the solketal yield in the ketalization catalyzed by PTA immobilized in the layer of poly(N- methyl-4-vinylpyridinium) grafted on silica nanoparticles (SNSs-g-PMVP/PTA). PTA with the size of 1- 2 nm were dispersed in the grafted-layer of PMVP under strong binding to positively charged pyridinium while the grafted-PMVP provided the hydrophobic environment improving the water-tolerance of PTA. In addition, acid-base interactions between PTA and the pyridine group in the grafted-PMVP transformed PTA hexahydrate to PTA trihydrate. Using SNSs-g-PMVP/PTA catalyst resulted in increasing of the solketal yield above 90% within an hour of the glycerol ketalization compared with 17% yield of solketal in the ketalization catalyzed by unsupported PTA.CO 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
Swedha, M.Alatar, Abdulrahman A.Okla, Mohammad K.Alaraidh, Ibrahim A....
14页
查看更多>>摘要：Visible light photocatalysis using nano heterostructures offers an eco-friendly alternative for the removal of organic molecules. Here, we reported an enhanced photocatalytic activity of g-C3N4/Ni-3(VO4)(2)/ZnCr2O4, a dual Z-scheme nano-heterojunction for the photocatalytic removal of p-chlorophenol (p-CP) and 5-fluorouracil (5-FU). The nano heterojunction was fabricated by a facile co-precipitation method. Initially, the fabricated nanocomposites (NCs) were characterized for Physico-chemical and optoelectronic properties, by XRD, XPS, SEM, TEM, UV-Visible DRS, BET, PL, and EIS. The fabricated g-C3N4/ Ni-3(VO4)(2)/ZnCr2O4 has shown excellent photocatalytic activity. The complete mineralization of both pCP and 5-FU observed after 160 and 200 min of visible light irradiation respectively. The mineralization of p-CP and 5-FU was confirmed by total organic carbon (TOC) estimation and the percentage of removal TOC for p-CP and 5-FU was 99.25% and 98.9% respectively. The stability of the particle was confirmed by six cycles test. The reusable efficiency of the NCs was found to be 99.7% after six consequent cycles. The stability of the NCs was confirmed by XRD and XPS analysis of reused photocatalyst. The scavengers assay and ESR analysis confirmed the major role of .OH radicals in enhanced photocatalytic activity. The degradation pathway of p-CP and 5-FU was determined by GC-MS/MS and the possible toxicity of the intermediate compounds was determined by the ECOSAR program, which shows the non-toxic nature of the end product on green algae, daphnia, and fish. The toxicity of the NCs was tested against Allium cepa which further confirm the non-toxic nature of NCs. The study suggests that fabricated g-C3N4/Ni-3(VO4)(2)/ZnCr2O4 NCs can be utilized for environmental remediation applications. (C) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：This paper reports the hydrothermal synthesis and characterization of poly(acrylic acid)-calcium phosphate passivated TiO2 nanoparticles (TiO2@PAA-CaP NPs). The efficient loading and release of doxorubicin (DOX) from the TiO2@PAA-CaP NPs was observed at pH = 7.4 and 5.2, respectively. The loading and encapsulation amount of DOX in TiO2@PAA-CaP NPs was approximately fifteen and eight times as large as that of unfunctionalized TiO2 NPs, respectively, suggesting the PAA-CaP passivation layer enhanced the interaction between DOX and TiO2@PAA-CaP NPs. The DOX-loaded TiO2@PAA-CaP (TiO2@PAA-CaP(DOX)) NPs exhibited much faster cumulative DOX release at acidic pH = 5.2 than at neutral pH = 7.4 because of the pH-responsive dissolution properties of the PAA-CaP passivation layer. TiO2@PAA-CaP(DOX) NPs showed higher cytotoxicity towards MCF-7 tumor cells than free DOX. Confocal fluorescence microscopy and flow cytometry confirmed the enhanced cellular uptake of TiO2@PAA-CaP(DOX) NPs followed by the intracellular release of DOX. Overall, TiO2@PAA-CaP(DOX) NPs demonstrated significantly higher total cytotoxicity towards MCF-7 tumor cells under UV-A irradiation, which was attributed to a synergistic effect between efficient DOX delivery and enhanced photoinduced reactive oxygen species (ROS) generation. This study provides a facile means of synthesizing TiO2-based multifunctional nanocarriers with pH-responsive drug delivery and ROS generation essential for high efficacy therapeutic applications in cancer treatments. (C) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Compared with metal-air batteries, Si-air batteries have advantages on gravimetric/volumetric capacity and safety. This novel battery using flat Si wafer as anode has been preliminarily researched in recent ten years. In this work, Si nanowires (NWs) have been fabricated on p < 100 > and n < 100 > Si wafers and their discharging behaviors under various operating conditions have been systematically analyzed compared with flat Si wafer anodes. Si NWs anodes universally exhibit longer discharge times than flat Si wafer anodes because of their larger specific surface areas and superior resistance to the passivation caused by SiO2 deposition. It is also demonstrated that a KOH electrolyte concentration of 1.9 M is the lowest threshold for the p < 100 > Si anode at a current density of 0.03 mA/cm(2), and the p < 100 > Si anode can discharge for more than 400 h. Furthermore, n < 100 > Si NWs anodes performed best with a discharge time of more than 500 h at higher current density of 0.05 mA/cm(2) with an electrolyte concentration of 6 M. This work can aid in understanding the electrochemical properties of silicon anodes with different configurations and doping types in Si-air batteries and provide direction for the operation of Si-air batteries at appropriate conditions. (C) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：To alleviate environment issues derived from CO2 emission, developing effective and economical methods for CO2 capture has attracted much attention for decades. Metal-organic frameworks possess high porosity and stability, which is favorable to the adsorption of small molecules. Herein, an aluminumbased MOF, aluminum terephthalate [MIL-53(Al)], was synthesized with H2O and N,N0dimethylformamide as co-solvent via microwave-assisted method for CO2 adsorption. The parameters including pre-mixing mode, microwave temperature, microwave power and reaction time were varied to study their influences on crystal structure, morphology and CO2 adsorption capacity of MW-MIL-53 (Al). Wherein, MW-MIL-53(Al) prepared with pre-mixing mode of stirring at 130 degrees C, 200 W and 3 h presents high crystallinity and rod-like morphology. The synthesized MW-MIL-53(Al) possesses relatively high BET surface area (961 m2/g), pore volume (0.46 cm3/g) and thermal stability (up to 480 degrees C), and its CO2 adsorption capacity is 2.16 mmol CO2/g adsorbent under 25 degrees C and 0.1 MPa, which is higher than CS-MIL-53(Al) synthesized via conventional solvothermal method at 130 degrees C for 48 h. (c) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
Manoj, DevarajRajendran, SaravananHoang, Tuan K. A.Ansar, Sabah...
9页
查看更多>>摘要：Three-dimensional (3D) metal-organic frameworks (MOFs) a class of porous materials with tunable structure and surface functionality has arisen as electrode materials especially, for electrochemical sensing of analytes. However, MOFs possess intrinsic drawbacks such as poor conductivity with an agglomeration of particles, which restricted the electrochemical signal response in terms of sensitivity and detection limits. In this regard, the present work aims to develop conducting Cu-MOF on HNTs, a good substate for in-situ growth of MOF nanostructures due to the existence of abundant negatively charged Si-OH that can help the growth of nanosized MOFs. The negatively charged siloxane (Si-O-Si) groups on the surface of HNTs can be attracted by positive charged Cu2+ ions present in the reaction mixture through strong electrostatic attraction. When subjected to hydrothermal treatment, the Cu2+ ions can form nano-sized Cu-MOF particles with assistance from 2-methylimidazole. Moreover, the presence of graphene oxide (GO) can improve the electrical conductivity, large surface area, and thus resulting in the formation of conducting Cu-MOF/HNTs/rGO nanocomposite. Owing to the synergetic desirable properties of active metal sites and high porosity offered by Cu-MOF, the high conductivity of rGO, and the large surface area of HNTs, the resultant Cu-MOF/HNTs/rGO modified GC electrode demonstrates superior electrochemical signal response towards dopamine and paracetamol. Moreover, the developed sensor exhibits wide linear ranges of 0.1 lM-130 lM and 0.5-250 lM, with a low detection limit of 0.03 lM and 0.15 lM for dopamine and paracetamol, respectively. (c) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：As the 'Global Methane Pledge' was launched at the UN COP26 climate conference in Glasgow, there is a growing need to develop efficient methods to remove lean methane emission or methane slip at low temperatures. In order to enhance the lean methane oxidation at temperatures lower than 200 degrees C, it can be effective to use ozone as an oxidant while applying an appropriate catalyst. In this study, we examined the activity of cobalt ion-exchanged BEA catalyst for ozone-induced lean methane oxidation under dry reaction conditions. The cobalt ion-exchanged BEA catalyst was more active than palladium and iron ion-exchanged BEA catalysts. It could initiate methane oxidation at-40 degrees C and reaches the highest methane conversion of 98% at 125 degrees C, maintaining the conversion higher than 50% in the temperatures from 55 to 185 degrees C. The most active cobalt species was the isolated mononuclear cobalt ions coordinated to BEA framework. Finally, we proposed the reaction mechanism based on the intermediate species identified by the Fourier transform infrared spectroscopy.(c) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Owing to the rapid increase in the demand for miniaturized flexible circuit devices, such as flexible copper clad laminate (FCCL), the development of a polymer substrate capable of adhering to the Cu film without deterioration of the dielectric properties is becoming a challenging issue. This study presents a process for forming a robust Cu adhesive layer on poly(ether ether ketone) (PEEK) while preserving the thermal, mechanical, and dielectric properties of PEEK. By simple UV irradiation without any precise control, the benzophenone group in PEEK chain structure can produce free-radicals (self UV-initiated polymerization). Using this principle, 2,3-epoxypropyl methacrylate and 3-tri(methoxysilyl)propyl methacrylate were copolymerized on the PEEK surface (PEEK -g-Polymer). The peel strength of the Cu adhered PEEK -g-Polymer, measured by a 90 degrees peel test, was 9.40 N/cm, which satisfies the required value for FCCLs. The differential scanning calorimetry, tensile, and dielectric tests confirmed that the thermal, mechanical, and dielectric properties of PEEK were preserved after the polymer grafting process, and the dielectric loss of PEEK -g-Polymer was lower than that of commercial polyimide-based substrate. This straightforward approach is expected to make a great contribution to achieving lower dielectric loss and miniaturization for 5G devices.
查看更多>>摘要：Photoelectrochemical water splitting under solar radiation is one of the most studied methods of solar to-fuel energy conversion. The search for effective photoelectrode materials operating under solar radiation is still ongoing, and in this paper, it is shown how to control the optical and photoelectrochemical properties of anodic tungsten oxide layers by changing the anodizing potential. Anodic tungsten oxide layers were obtained in an aqueous electrolyte with 1 M ammonium sulfate and 75 mM ammonium fluoride at a constant voltage of 20-70 V and annealed at 500 degrees C in air. Comprehensive characterization of materials was performed using SEM, XRD, UV-Vis DRS, Mott-Schottky analyses, and photoelectrochemical water splitting tests. It was found that with increasing the anodizing potential the band gap narrows from 3.09 eV to 2.75 eV, donor density increases, and the IPCE spectrum shifts towards the visible light range. CO 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：The Functional layers with excellent heat-resistence nanofiltration (HRN) property were designed by fixing thermal stabilized quinoxaline diamines (QHDA) on poly (m-phenyleneisophthalamide) (PMIA) substrate through interfacial polymerization. QHDA was used as aqueous monomer while cinnamoyl chloride (CNC), isophthaloyl chloride (IPC) and trimesoyl chloride (TMC) were served as organic monomers to realize the immobilization of thermally stable N heterocycles. The experimental results stated clearly that the compact package reaction of QHDA with TMC lead a raise of thermal stability and salts rejection at high temperature stream. With the optimal TMC and 0.5 wt.% QHDA, the as-developed membrane achieved the excellent NF performance and thermal stability. The rejection of MgSO4 reached to 94.6 % at 30 C and hardly decrease at 90 C. The reduction in rejection was satisfactory at high temperatures. The functional layer still showed highly stability after 10 h long-term operation at 90 C with only 2.8 % reduction in MgSO4 rejection. Besides, the excellent Mg2+ and poor Li+ rejection made this membrane have huge potential in the application of extracting Li+ from brine. The separation factor of Mg2+-Li+ at high temperature was satisfactory. Over all, this study offered a prospect technology to exploit heat-resistant membranes for extraction lithium at high temperature. (C) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
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