CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Xiaodong Zhu,Fantao Kong,Xinsheng Ma
Li-added CaO-B 2 O 3 -SiO 2 (CBS) dielectric microwave substrates for low temperature co-fired ceramic (LTCC) applications were prepared using a solid-state reaction, and the effect of the LiF additive on the sintering behavior, dielectric performance and mechanical properties of the product was investigated. In this presently reported work, we found that the LiF additive could effectually reduce the sintering temperature of the CBS ceramics and also substantially improved the densification, dielectric and mechanical properties of it. The experimental results showed that an addition of 3 wt% LiF to the sample sintered at 790 °C resulted in a main crystalline phase of β-CaSiO3 which had excellent proprieties. These included an excellent degree of densification, ε r of 6.43, tan δ of 5.9 × 10 −4 and a volume resistivity of 8.20 × 10 11 Ω cm at 1 MHz, and flexural strength of 241 MPa.
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高影响因子
NANO
·
2018
·
IF 1.1
Zongxue Yu,Xia Min,Fei Li,Qi Chen
In the study, the Ag–SiO 2 –APTES nanocomposite was synthesized via the self-assembly method to prepare Ag–SiO 2 and subsequently used 3-aminopropyltriethoxysilane (APTES) to functionalize its surface. The as-prepared Ag–SiO 2 –APTES nanocomposite was embedded into poly(vinylidene fluoride) (PVDF) membrane by the co-blending way to fabricate the Ag–SiO 2 –APTES membrane. The Ag–SiO 2 –APTES nanocomposites were characterized by X-ray diffraction (XRD). These membrane materials were characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and FT-IR spectra. The performance of membrane was investigated simultaneously for removing the organic dye methylene blue (MB), Rhodamine B, Direct Red 28 and anti-microbial ability. The experimental results demonstrated that the Ag–SiO 2 –APTES modified membrane were presented to be more hydrophilic with a contact angle 55.6 ∘ , whereas the pristine PVDF membrane was 81.8 ∘ . The dye rejection ratios were also improved after adding Ag–SiO 2 –APTES, which reached 86.8% for MB, 87% Rhodamine B, 88% for Direct Red 28, besides, the removal rate of MB was about 98.7% at pH = 11. More importantly, the Ag–SiO 2 –APTES membranes exhibited excellent antifouling properties for treating MB solution and could reach 85% of flux recovery ratio after four cyclic experiment. Finally, via inhibition zone method of antimicrobial test Ag–SiO 2 –APTES membrane exhibited the antimicrobial activity against Escherichia coli ( E. coli ) excellently. The novel antifouling and antibacterial Ag–SiO 2 –APTES membrane has a potential for dye wastewater treatment and water purity.
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Arabian Journal of Chemistry
·
2018
·
IF 2.969
Du Yue,Jiaheng Lei,Lina Zhou,Xiaodi Du,Zhenran Guo,Junsheng Li
Ordered meso/macroporous H 3 PW 12 O 40 /SiO 2 nanocomposites with high specific surface areas were prepared using cationic surfactant and monodispersed polystyrene spheres (PS) as dual-template. The characterization results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption-desorption, and small-angle XRD patterns confirmed the existence of ordered meso/macroporous structure and the wide-angle XRD patterns, Fourier transform infrared spectroscopy (FTIR), X-ray photoemission spectroscopy (XPS) measurements suggested the high dispersivity of the Keggin-type heteropolyacid (HPA) on silica matrix. There was an optimum value of cationic surfactant usage and proper calcination temperature of ordered meso/macroporous H 3 PW 12 O 40 /SiO 2 catalyst leading to ultra-high specific surface areas. Furthermore, the ordered meso/macroporous H 3 PW 12 O 40 /SiO 2 catalyst was evaluated for ultra-deep oxidative desulfurization (ODS) of cyclic sulphur-containing compounds using hydrogen peroxide (H 2 O 2 ) as oxidant. Under optimum reaction conditions, dibenzothiophene (DBT) could be removed within 100 min at 30 °C by meso/macroporous H 3 PW 12 O 40 /SiO 2 catalyst. The excellent catalytic activity should be attributed to the combination of ordered meso/macroporous architecture and high surface area of H 3 PW 12 O 40 /SiO 2 catalyst which promoted the mass transport of reactants and products in the pore channel and provided more accessible catalytic active sites. In addition, the meso/macroporous H 3 PW 12 O 40 /SiO 2 catalyst showed good stability with only 1.9% efficiency decreased after 6 cycles.
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BIOSENSORS & BIOELECTRONICS
·
2019
·
IF 9.518
Hui-Fang Cui,Ting-Ting Zhang,Qi-Yan Lv,Xiaojie Song,Xiao-Jing Zhai,Gai-Gai Wang
A stable and sensitive electrochemical acetylcholinesterase (AChE) biosensor for detection of organophosphorus pesticides (OPs) was developed by doping Au nanorods (AuNRs)@mesoporous SiO 2 (MS) core-shell nanoparticles into CS/TiO 2 -CS (CS denotes for chitosan) immobilization matrix. AuNRs@MS core-shell nanoparticles were synthesized and characterized. The doping and the biosensor fabrication process were probed and confirmed by scanning electron microscopy and electrochemistry techniques. The doping conditions were optimized. The matrix both before and after AChE immobilization had a mesoporous nanostructure . The nanoparticles dispersed homogeneously within the matrix. The doping significantly enhanced the electro-conductivity of the TiO 2 -CS hydrogel, and dramatically improved the bioelectrocatalytic activity and OPs detection sensitivity of the AChE immobilized matrix. The detection linear ranges for both dichlovos (DDVP) and fenthion were from 0.018 μM (4.0 ppb) to 13.6 μM, and the limit of detection (LOD) was 5.3 nM (1.2 ppb) and 1.3 nM (0.36 ppb), respectively. The biosensor exhibited high reproducibility and accuracy in detecting OPs spiked vegetable juice samples. In addition, it exhibited very high detection stability and storage stability. The developed AChE biosensor was provided to be a promisingly applicable tool for OPs detection with high reliability, simplicity, and rapidness.
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PubMed
高影响因子
ENERGY & FUELS
·
2019
·
IF 3.021
Zhiming Huang,Ping Li,Xiao Luo,Xia Jiang,Lei Liu,Fan Ye,Jiazhe Kuang,Yue Luo,Yuanzhu Mi
In the current study, novel environmentally friendly and interfacially active carbon nanotubes/SiO2 nanomaterials (CNTs/SiO2) for emulsified crude oil separation were prepared via grafting nano-SiO2 on the surface of oxidized carbon nanotubes (Ox-CNTs). The structure of the as-prepared CNTs/SiO2 was characterized by Fourier transform infrared spectroscopy, UV–visible absorption spectra, Raman spectra, X-ray diffraction spectra, thermogravimetric analysis, field-emission scanning electron microscope, and energy-dispersive X-ray spectroscopy. Besides, three-phase contact angles (θ) were employed to evaluate the wettability of CNTs/SiO2. Also, it was found that the θ value of CNTs/SiO2 was about 90°. The nanomaterials with interfacial activity can spontaneously assemble at the oil–water interface, thus improving the droplet coalescence in the emulsion. Afterward, the demulsification performance was evaluated in crude-oil emulsions using the bottle test, which demonstrated that the demulsification efficiency demulsification efficiency could reach 87.40%. Also, the water phase was clear, while the optimum concentration and sedimentation time were 500 ppm and 30 min, respectively. Furthermore, the possible demulsification mechanism was evaluated by an optical microscope. The findings in this work might provide a novel environmentally friendly and interfacially active nanomaterial as a crude oil demulsifier.
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POLYMER COMPOSITES
·
2019
·Vol. 41
·期 1
·381-390
·
IF 2.268
Dongna Li,Jirui Fu,Xiaojun Ma
A biocomposite of poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)/nano-SiO 2 modified with silane coupling agent KH570 (KH570-SiO 2 /PHBH) were prepared by solution-casting method. SiO 2 modified with KH570 exhibited improved uniform dispersion than that of pure nano-SiO 2 , and maximum thermal decomposition temperature range and crystallinity ( X c ) of KH570-SiO 2 /PHBH are 8.6°C and 119.7% higher than that of neat PHBH. Compared to the neat PHBH, a 75.4% and 70.8% improvement in Young's modulus and tensile strength were obtained. The water-vapor transmission and oxygen permeance of KH570-SiO 2 /PHBH decreased by 46.2% and 618.6%, respectively. The oxygen barrier property is equivalent to that of polyvinylidene chloride. Simultaneous enhancements on the thermal stability, mechanical, crystallizing, and barrier properties were mainly caused by uniform dispersion of modified nano-SiO 2 and solid interfacial bonding between filler and matrix.
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Scientific Reports
·
2019
·Vol. 9
·期 1
·1-9
·
IF 4.011
Yang Yushan,He Haishan,Li Yougui,Qiu Jian
Robust, buoyant, superhydrophobic PVB/SiO 2 coatings were successfully formed on wood surface through a one-step solvothermal method and a nanoimprint lithography method. The as-prepared PVB/SiO 2 /wood specimens were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermogravimetric/differential thermogravimetric (TG–DTG) analyses. The superhydrophobic property and abrasion resistance of rose-petal-like wood were measured and assessed by water contact angle (WCA) and sand abrasion tests. The results show that PVB/SiO 2 /wood not only exhibited a robust superhydrophobic performance with a WCA of 160° but also had excellent durability and thermostability during the sand abrasion tests and against corrosive liquids. Additionally, the as-prepared PVB/SiO 2 /wood specimens show high buoyancy.
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PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2017
·
IF 3.359
Junliang Wang,Yuanyang Lou,Xiaowei Zhuang,Shuang Song,Weiping Liu,Chao Xu
A magnetic core–shell Pr 6 O 11 /SiO 2 @Fe 3 O 4 catalyst using chemical precipitation was prepared. Its structure was confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and energy-dispersive X-ray spectrum. The catalytic activity was evaluated by the catalytic ozonation of acetochlor. The results showed that the catalyst could effectively improve the acetochlor removal and mineralization. The total organic carbon removal reached 37.3% with the catalyst at 120 min, whereas the removal was 14.1% with ozonation alone. The catalyst was proved to be stable and recyclable by determining the concentration of the leaching praseodymium ions and the catalyst’s activity after repeated use. The effect of the radical scavengers indicated that the catalytic ozonation process followed an OH reaction mechanism. In addition, we employed Chlorella and zebrafish as model organisms to investigate the aquatic toxicity of the treated solution and the dissolved praseodymium ions. We found that the aquatic toxicity of the reaction solution decreased with an increase in the degradation time, and no obvious toxicity was found for the dissolved praseodymium ions.
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JOURNAL OF RARE EARTHS
·
2017
·
IF 2.429
Hong DING,Yanling ZHAO,Qianlin DUAN,Junwen WANG,Kan ZHANG,Guangyue DING,Xianmei XIE,Chuanmin DING
Fe 3 O 4 @SiO 2 magnetic nanoparticles functionalized with mesoporous cerium oxide (Fe 3 O 4 @SiO 2 @ m CeO 2 ) was fabricated as a novel adsorbent to remove phosphate from water. The prepared adsorbent was characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption and vibrating sample magnetometry (VSM), and its phosphate removal performance was investigated through the batch adsorption studies. Characterization results confirmed that mesoporous cerium oxide was successfully assembled on the surface of Fe 3 O 4 @SiO 2 nanoparticles, and the synthesized adsorbent possessed a typical core-shell structure with a BET surface area of 195 m 2 /g, accessible mesopores of 2.6 nm, and the saturation magnetization of 21.11 emu/g. The newly developed adsorbent had an excellent performance in adsorbing phosphate, and its maximum adsorption capacity calculated from the Langmuir model was 64.07 mg/g. The adsorption was fast, and the kinetic data could be best fitted with the pseudo-second-order kinetic model. The phosphate removal decreased with the increase of solution pH (2 to 10), while the higher ionic strength slightly promoted the phosphate adsorption. The presence of Cl − and SO 4 2− could enhance the adsorption of phosphate whereas HCO 3 − had interfering effect on the phosphate adsorption. The adsorption mechanism was studied by analyzing Zeta potential and FTIR spectroscopy, and the results indicated that the replacement of the surface hydroxyl groups by phosphate ions with the formation of inner-sphere complex played a key role in the phosphate adsorption. The spent adsorbent could be quickly separated from aqueous solution with the assistance of the external magnetic field, and the adsorbed phosphate could be effectively desorbed using a 1 mol/L NaOH solution.
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FUEL
·
2017
·
IF 4.601
Zhuqian Xiao,Yu Fan,Yongjie Cheng,Qiang Zhang,Qing Ge,Ruyi Sha,Jianbing Ji,Jianwei Mao
The catalytic transformation of cellulose to polyols is one of the significant strategies to overcome the shortage of fossil fuels. Here we report a simple but effective preparation method for Ni-W/SiO 2 catalysts by introduction of chelating agents (ammonium hydroxide and ethanediamine) coupled with organic reducing agent (ethylene glycol). The ethylene glycol (EG) yield from microcrystalline cellulose could reach up to 63.3% at 240 °C, 5.0 MPa H 2 for 2.0 h over 15%Ni-20%W/SiO 2 -EEG catalyst. Moreover, some key parameters of process conditions including calcining temperature, reaction temperature and time, H 2 pressure and the recycling use of catalysts were investigated. Both theoretical and experimental studies suggested that 15%Ni-20%W/SiO 2 -EEG catalyst showed the best activity and stability for cascading steps for EG formation at this reaction condition. By the detailed analysis of Ni-W/SiO 2 catalysts after calcination via FT-IR, XRD , XPS , thermogravimetry (TG), TEM and element mapping, it could be concluded that on the surface of 15%Ni-20%W/SiO 2 -EEG catalyst, the particles showed less agglomeration and more homogeneous on the surface of SiO 2 . Some Ni x W y alloys (NiW, Ni 2 W 4 C) were also formed. Furthermore, it was found that the introduction of ethanediamine could promote the actual loading of nickel and tungsten species slightly according to the analysis of ICP-OES test.
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CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Zhuoqing An,Yuan Gao,Jiajing Chen
The CaO-MgO-Al 2 O 3 -SiO 2 (CMAS) glass-ceramics containing complex nucleation agents including La 2 O 3 and Fe 2 O 3 were prepared by melt process. The effects of these complex nucleation agents on the crystallization and microstructure of CMAS glass-ceramics were investigated through the thermal analysis (DSC), X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM) and Raman spectroscopy. The results indicated that the addition of La 2 O 3 and Fe 2 O 3 decreases viscosity and ion movement resistance. Furthermore, the La 2 O 3 can increase the crystallization peak temperature, while the Fe 2 O 3 has an inverse effect. The crystallization activation energy decreased from 298.87 to 264.26 kJ/mol as the mole ratio of La 2 O 3 increased to 2%. Conversely, when the mole ratio of Fe 2 O 3 increased to 2%, the crystallization activation energy increased from 298.87 to 347.21 kJ/mol. However, the addition of La 2 O 3 and Fe 2 O 3 decreased the Avrami parameter and promoted the surface crystallization within the CMAS glass system, as confirmed by the microstructure analysis. The crystal show branch-like crystal morphology when La 2 O 3 adding, whereas Fe 2 O 3 addition led to a compact, seaweed-like morphology with a fractal structure. With decreasing La 2 O 3 and increasing Fe 2 O 3 , the width of the dendritic branches increased. The major crystal phases detected on the surface were augite and diopside phase. Fe is predominantly present in the augite phase and La is primarily incorporated as a solid solution within the crystal phase.
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DYES AND PIGMENTS
·
2016
·
IF 4.055
M.M. Mikhailov,V.V. Neshchimenko,Chundong Li
This study carried out on the diffuse reflective spectra of zinc oxide modified by Al 2 O 3 , ZrO 2 , SiO 2 , CeO 2 , TiO 2 and Y 2 O 3 nanoparticles . It was established that during the modification are formed the solid solutions between zinc oxide and nanopowder as Al 2 ZnO 4 , ZrZnO 3 , Zn 2 SiO 4 , Ce x Zn (1−х) О y , Zn 2 TiO 4 , Y x Zn (1−x) O y . The diffuse reflection spectra of the modified powders are changed in the UV and visible range with a maximum at 395 nm. This band is determined by the intrinsic point defects in the crystal lattice of ZnO as interstitial zinc ions and zinc vacancy. In the IR region also recorded changes due to the absorption of OH-groups adsorbed on the surface modified zinc oxide.
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