JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2021
·Vol. 168
·期 2
·022504
·
IF 4.316
Shahid Khan,Chaoyan Fang,Yecheng Ma,Mahmood ul Haq,Mohammad Nisar,Gang Xu,Yong Liu,Gaorong Han
The aim of the study was to determine the effect of inorganic core-shell SiO2 nanoparticles modified with polymethyl methacrylate (PMMA) layer, on the optical and electrochemical properties of poly vinylidenefluoride-co-hexafluoropropylene (PVDF-HFP) gel polymer electrolyte (GPE). The core-shell SiO2 nanoparticles were first modified with PMMA to improve its dispersibility and compatibility in the polymer matrix. The morphology and structural properties of the core-shell SiO2 nanoparticles before and after modification were characterized by XRD, FTIR and SEM analysis. Then the modified SiO2 nanoparticles were used to prepare the composite GPE, composed of chemically modified core-shell structured SiO2-PMMA and PVDF-HFP polymer matrix. The transformation of nano-silica to SiO2-PMMA nanoparticles shows the better compatibility of PMMA and PVDF-HFP that favours the silica to be well dispersed in the organic matrix and significantly improve the doping effect. Various concentrations of modified SiO2-PMMA were used to dope PVDF-HFP GPEs. The results indicate that the 10% doping shows the highest ionic conductivity i.e. 2.22 × 10−3 s cm−1. In addition, the composite GPEs show the high transmittance and good thermal stability; therefore it can add important insight into developing high-performance materials for electrochromic devices.
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Nanoscale
·
2021
·Vol. 13
·期 6
·3860-3867
·
IF 7.79
Meng Li,Xiao Zhang,Ping Yang
Silica coating can effectively solve the stability issue of lead halide perovskite nanomaterials. However, it is difficult to achieve aqueous SiO2 coating on hydrophobic CsPbBr3 nanocrystals (NCs). In this paper, the hydrolysis process of tetramethoxysilane was controlled to get a homogeneous SiO2 coating or a NC/SiO2 Janus structure. In step 1, the Cs4PbBr6 NCs were silanized using partially hydrolyzed tetramethoxysilane (PH-TMOS). During this process, the Si–OH groups which came from PH-TMOS were absorbed onto the surface of the Cs4PbBr6 NCs with the removal of hydrophobic oleic acid (OA) ligands. In step 2, phase transformation from Cs4PbBr6 to CsPbBr3 occurred owing to the injection of water. Meanwhile, further hydrolysis of TMOS took place and generated cross-linked Si–O–Si. Because the silanization in step 1 created lots of growth sites, the condensation of SiO2 was not limited to the interface between water and hexane. After growing for 12 h, the fully covered CsPbBr3@SiO2 capsules were prepared. The anion exchange reactions of the CsPbBr3@SiO2 capsules were studied. Only one even and symmetric PL peak was apparent during the anion exchange process, which was different from the bare CsPbBr3 NCs. This result demonstrated that the SiO2 shell can act as a buffer layer to block the direct contact of CsPbBr3 with the excess PbBr2 precursor in solution. Compared with the CsPbBr3 NCs, CsPbBr3@SiO2 showed better stability in polar solvent and air. A bright green emission was also observed under UV light after 90 days. The successful preparation of CsPbBr3@SiO2 capsules with enhanced stability paves the way for the further development of lead halide perovskite nanomaterials.
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高影响因子
Membranes
·
2021
·Vol. 11
·期 11
·803
·
IF 4.106
Qianqian Xu,Yuchao Chen,Tonghu Xiao,Xing Yang
The use of poly(vinylidene fluoride) (PVDF) microfiltration (MF) membranes to purify oily water has received much attention. However, it is challenging to obtain high-performance PVDF microfiltration membranes due to severe surface fouling and rapid decline of permeability. This study explored a new approach to fabricate high-performance PVDF/silica (SiO2) composite membrane via the use of a polymer solution featuring lower critical solution temperature (LCST) characteristics and the non-solvent thermally induced phase separation method (NTIPS). Coupling with morphological observations, the membrane formation kinetics were analyzed in depth to understand the synergistic effect between the LCST solution properties and fabrication conditions in NTIPS. Utilizing such a synergistic effect, the transition from finger-like macrovoid pores to bi-continuous highly connected pores could be flexibly tuned by increasing the PVDF concentration and the weight ratio of SiO2/PVDF in the dope solution and by raising the coagulation temperature to above the LCST of the solution. The filtration experiments with surfactant-stabilized oil-water emulsion showed that the permeation flux of the PVDF/SiO2composite membranes was higher than 318 L·m−2·h−1·bar−1and the rejection above 99.2%. It was also shown that the PVDF/SiO2composite membranes, especially those fabricated above the LCST, demonstrated better hydrophilicity, which resulted in significant enhancement in the anti-fouling properties for oil/water emulsion separation. Compared to the benchmark pure PVDF membrane in oily water purification, the optimal composite membrane T70 was demonstrated via the 3-cycle filtration experiments with a significantly improved flux recovery ratio (Frr) and minimal reduced irreversible fouling (Rir). Overall, with the developed method in this work, facile procedure to tune the membrane morphology and pore structure was demonstrated, resulting in high performance composite membranes suitable for oil/water emulsion separation.Keywords:PVDF/SiO2composite membrane;lower critical solution temperature (LCST);nonsolvent thermally induced phase separation (NTIPS);structural control;oil-in-water emulsion
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Yijie Feng,Wenjiao Sang,Zhiyi Deng,Shiyang Zhang,Cuihua Li
Co-N-C@SiO 2 with Co, N doped carbon as core and SiO 2 as shell was successfully synthesized by template method, and SiO 2 shell was about 43 wt%. Impressively, the SiO 2 shell increased the active sites of the core in Co-N-C@SiO 2 preparation, and reduced the loss of active sites during use. Co-N-C@SiO 2 /PMS was a 1 O 2 dominated non-radical reaction, which was less interfered by solution pH and water constituents. In addition, Co-N-C@SiO 2 possessed better cycling performance compared with Co-N-C. Finally, the possible SMX degradation pathways were presented based on the identified intermediate products.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2021
·
IF 4.539
Han Jia,Jiajun Dai,Lingchun Miao,Xin Wei,Hongtao Tang,Pan Huang,Haidong Jia,Juan He,Kaihe Lv,Dexin Liu
The Janus nanoparticles stabilized Pickering emulsions showed great application potential in various fields, including enhanced oil recovery (EOR). In this study, the amphiphilic Janus-SiO 2 nanoparticles (Janus-C12) are successfully synthesized by the Pickering emulsion method and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), ζ-potential and contact angle measurements. The phase inversion from oil-in-water (O/W), multiple oil-in-water-oil (O/W/O) emulsion, to water-in-oil (W/O) emulsions was observed with the delicate control for the modification degrees of Janus-C12. The possible emulsification mechanisms for various Janus-C12 stabilized emulsions were proposed. The multiple O/W/O emulsion stability in harsh conditions and the influence factors (nanoparticles concentration, water/oil volume ratio and NaCl concentration) were studied systematically. Moreover, the Janus-C12–79% stabilized multiple O/W/O Pickering emulsions exhibited excellent EOR performance (additional oil recovery of 27.2%) in core flooding tests, and the possible EOR mechanism was explored via microscopic visualization experiments.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2021
·
IF 6.953
Jumin Hou,Xiaoxia Yan
The ultrasonic treatment could decrease the particles size of chitosan-SiO 2 particles. The EDS of samples with ultrasonic treatment for 0 min and 10 min indicated that the SiO 2 was present in prepared chitosan-SiO 2 particles. When the ultrasonic time reached 10 min, the chitosan-SiO 2 nanoparticles formed and the mean size was 506.7 ± 3.42 nm and the Zeta potential of the chitosan-SiO 2 nanoparticles was greater than 30 mV, showing the suspension was a stable dispersed liquid. The chitosan-SiO 2 nanoparticles were used as reinforcement in thermoplastic starch films to further verify their performance in enhanced films. The water contact angle of thermoplastic starch film reinforced with chitosan-SiO 2 nanoparticles was 44.13 ± 5.02° and had a good mechanical property with tensile strength of 8.91 ± 0.49 MPa. This study indicates that chitosan-SiO 2 nanoparticles could be used as a reinforcement to prepare thermoplastic starch films and promote the application of chitosan nanoparticles in nanocomposite films.
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高影响因子
CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Mengting Yu,Shuangshuang Zhao,Lu Yang,Na Ji,Yanfei Wang,Liu Xiong,Qingjie Sun
The development of environmentally friendly and transparent superhydrophilic food packaging materials is essential in our daily lives. The objective of this study was to develop a simple method of preparing a superhydrophilic, transparent, and biodegradable composite film. The composite film was obtained by soaking a chitosan-sodium phytate film in an ethanol solution of SiO 2 nanoparticles . The results showed that when the chitosan-sodium phytate film was coated with SiO 2 nanoparticles that were dissolved in 75% ethanol, its water contact angle (WCA) was reduced from 100° to 3°, and the film surface was changed from a hydrophobic to a superhydrophilic. Furthermore, the oxygen transmission rate (OTR) was significantly reduced, and the mechanical properties of the film were improved. The method is easy to carry out and can be used for the potential production of superhydrophilic materials.
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高影响因子
Analytical Methods
·
2021
·Vol. 13
·期 26
·2974-2980
·
IF 2.896
Xinze Wu,Yifei Cao,Bin Sun,Huaixia Chen,Xueping Dang,Xiaolan Liu,Youhong Ai
In this study, magnetic Fe3O4@SiO2@β-cyclodextrin copolymerized microparticles were synthesized and applied for the extraction of methyl parathion and fenthion in lettuce samples followed by HPLC-UV detection. The magnetic β-cyclodextrin copolymerized microparticles were prepared by dispersion polymerization with acryloyl β-cyclodextrin as the functional monomer and ethylene glycol dimethyacrylate as the crosslinker. The composite magnetic microparticles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, magnetic measurement, and thermogravimetric analysis, and used as the adsorbent of magnetic solid-phase extraction (MSPE) for methyl parathion and fenthion. The extraction conditions including sample pH and ionic strength, desorption solvent type and volume, and adsorption and desorption times were optimized. Under the optimal extraction conditions, an MSPE-HPLC-UV method was developed for the detection of methyl parathion and fenthion in lettuce. Wide linear ranges of 1.0–200 μg kg−1 (R2 = 0.9998) for methyl parathion and 1.5–200 μg kg−1 (R2 = 0.9978) for fenthion were obtained and the limits of detection were 0.3 μg kg−1 for methyl parathion and 0.5 μg kg−1 for fenthion in lettuce, respectively. The proposed method was applied for the determination of methyl parathion and fenthion in lettuce with satisfactory recoveries between 89.2–101.2%, and relative standard deviations were less than 9.1%. Thus, the MSPE-HPLC-UV method has high accuracy and sensitivity for the analysis of methyl parathion and fenthion in lettuce samples.
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高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Linfeng Bai,Kezhu Xu,Wanquan Jiang,Min Sang,Qunling Fang,Shouhu Xuan,Xinglong Gong
Advanced nanocatalysts integrating with high activity and recyclability is one of the most important issues in heterogeneous catalysis. Magnetic hierarchical nanostructures comprising noble metal nanocrystals confined within a protecting penetrable shell will be favored as an efficient candidate toward robust catalytic reactions. This work reports a proof-of-concept magnetic separable nanocatalyst with the polydopamine (PDA)-confined-Au-nanocrystals assembled on the hierarchical surface of Fe 3 O 4 @SiO 2 @γ-AlOOH microflower (Fe 3 O 4 @SiO 2 @γ-AlOOH@Au/PDA). Because of the high surface area of γ-AlOOH hierarchical nanoarchitectures, the loading capacity and dispersity of Au nanocrystals are both improved. These magnetic microflowers present excellent catalytic efficiency and cycling performance in reduction of 4-nitrophenol to 4-aminophenol, which can be ascribed to the superior structure of catalyst. After 9 cycles, the activity of Fe 3 O 4 @SiO 2 @γ-AlOOH@Au/PDA maintains as high as 97.3% due to the protection of PDA shell. In comparison to the spherical Fe 3 O 4 @SiO 2 @Au/PDA, the as-prepared Fe 3 O 4 @SiO 2 @γ-AlOOH@Au/PDA microflowers exhibit quicker catalytic dynamic. The concept of hierarchical nanostructure and penetrable PDA protective layer will be instructive for fabricating high-performance nanocatalysts.
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VACUUM
·
2021
·
IF 3.627
Dong-Guang Liu,Ting-Ting Yang,Yu-Lan Liu,Lai-Ma Luo,Yu-Cheng Wu
Tritium permeation is an essential challenge that should be solved in fusion reactors. In this study, the inner wall SiO 2 coating of the 316L stainless steel pipeline for tritium permeation barrier (TPB) is prepared by slurry-spraying method. The microstructure, phase composition, thermal shock resistance, and hydrogen permeation resistance of the SiO 2 coating are investigated. Results show that the coating is amorphous SiO 2 , and the coating is bonded well to the substrate and the thickness of the coating is about 10–15 μm. After six thermal shock treatments, the SiO 2 coating exhibit good thermal shock resistance stability below 700 °C. Results from the hydrogen penetration test indicate that the hydrogen resistance capability of the SiO 2 coating is 16-fold higher than that of the 316L stainless steel substrate. Hydrogen resistance is also 6-fold more stable than that of 316L stainless steel. These characteristics improve significantly the hydrogen resistance performance of the 316L stainless steel substrate.
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JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Han Jia,Wenjian Huang,Yugui Han,Qiuxia Wang,Juan He,Jinyong Song,Jiajun Dai,Hui Yan,Dexin Liu
The effects of both hydrophilic and hydrophobic SiO 2 nanoparticles (NPs) on the viscoelasticity of stearyltrimethylammonium bromide/sodium salicylate wormlike micelles (WLMs) solutions were investigated. The micelle-nanoparticle junctions obviously increased the contour length L c of the WLMs to facilitate the viscoelasticity of WLMs solution, which could be reflected by cryo-TEM images and Maxwell model. The effects of SiO 2 NPs on the zero-shear viscosity and the flow activation energies of WLMs with different surfactant alkyl chain lengths were explored in the controlled experiments. It was found that the viscoelasticity of WLMs/NPs mixture was associated with the strength of the hydrophobic effect between the SiO 2 NPs and surfactant molecules in the micelle-nanoparticle junction. The number densities of micelle-nanoparticle junction in hydrophilic and hydrophobic SiO 2 NPs systems were calculated by the mathematical model to confirm our proposed hypothesis.
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Journal of the Taiwan Institute of Chemical Engineers
·
2020
·
IF 4.794
Chang Sun,Jian Lu,Yilin Wu,Minjia Meng,Chao Yu,Zeqing Dong,Muning Chen,Yongsheng Yan,Yan Sun
Development of high-efficiency separation materials with specific recognition sites has become an urgent and important task. Herein, a synergetic strategy based on polydopamine (pDA) and silicon dioxide nanoparticles (SiO 2 ) was successfully designed and developed for the preparation of imitated core-shell-based cloxacillin-imprinted nanocomposite membranes (ICCIMs-D/S). Cloxacillin (Col) was selected as the template resulting from the potential threat to environment and human health. As to the synthesis procedure of ICCIMs-D/S, the pDA-modified layers were uniformly loaded onto substrate membranes by developing an elevated phase transformation method. Based on it, the synergy processes of pDA and SiO 2 could be achieved on surface of porous membranes. The ICCIMs-D/S with Col-imprinted recognition sites were finally synthesized by the photo-initiated “mercapto-alkenes click chemistry” method using methacrylic acid as functional monomers. Notably, the satisfactory rebinding selectivity ( α >4.0) and permselectivity ( β >4.0) with outstanding regeneration performance (only 5.11% decrease after ten regeneration cycles) indicated the superior selectivity and stability of the as-obtained ICCIMs-D/S. The preparation strategy and ICCIMs-D/S developed in this work is expected to provide a feasible idea for selective separation of Col from wastewater.
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