CHEMICAL ENGINEERING SCIENCE
·
2021
·
IF 4.311
Zhongliang Huang,Yujia Yuan,Miaomiao Song,Zhimian Hao,Jingran Xiao,Dongren Cai,Abdul-Rauf Ibrahim,Guowu Zhan
Herein, we fabricated a series of bimetallic Pt-Ni catalysts supported on mesoporous silica nanorods ( m SNR, specific BET surface area of 1802 m 2 g −1 ) to study the effect of Ni/Pt ratio on the product selectivity in CO 2 hydrogenation. Both monometallic Pt/ m SNR and Ni 50 Pt 50 / m SNR catalysts revealed negligible methane selectivity. However, methane became the major product only when increasing the Ni/Pt ratio up to 9. X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma (ICP) characterizations showed that the Pt/Ni ratio on the catalyst surface was appreciably higher than the bulk composition, suggesting the enrichment of Pt on the surface ( e.g. , Pt/Ni of 61/39 for Ni 50 Pt 50 / m SNR catalyst). The Pt/Ni ratio was crucial in determining the CH 4 /CO selectivity, and the addition of a tiny amount of Pt could improve the catalytic performance and stability of Ni/ m SNR. Among the different catalysts, Ni 98 Pt 2 / m SNR showed the best CO 2 conversion (59%) and CH 4 selectivity (96%) at 400 °C, 0.1 MPa, 9600 mL h −1 g cat −1 , and H 2 /CO 2 of 3. In-situ DRIFTS and temperature-programmed surface experiments suggested that the dissociated adsorption of CO 2 on the Pt site led to CO*, but the strongly adsorbed CO* cannot be further hydrogenated to CH 4 over the Pt site. In contrast, CO* could be further hydrogenated into CH 4 via CH x O* intermediates on adjacent Ni sites.
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高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Zhihui Chen,Jun Yao,Bo Ma,Bang Liu,Jonghyok Kim,Hao Li,Xiaozhe Zhu,Chenchen Zhao,Meseret Amde
The presence of chlorophenols in water and wastewater is considered a serious environmental issue . To eliminate these micropollutants, biodegradation of chlorophenols using enzyme-nanoparticle conjugated biocatalyst, is proposed as an economical and eco-friendly method. Herein, amino-functionalized superparamagnetic Fe 3 O 4 @SiO 2 –NH 2 nanoparticles with core-shell structure were constructed as a promising carrier for immobilization of laccase from Trametes versicolor . Compared with free laccase, Fe 3 O 4 @SiO 2 –NH 2 -Laccase displayed remarkable outcomes in all major areas such as temperature and storage stabilities, and tolerance to organic solvents and metal ions . The biocatalytic performance and reusability of Fe 3 O 4 @SiO 2 –NH 2 -Laccase were evaluated for the degradation of 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) in repeated cycles. Even after 10 successive reuses, the degradation rate of 2,4-DCP and 2,4,6-TCP were found to be 54.9% and 68.7%, respectively. The influences of solution pH, initial chlorophenol concentration, and temperature on the degradation rate of these two chlorophenols were evaluated. The degradation intermediate products including dimers, trimers , and tetramers of 2,4-DCP and 2,4,6-TCP were identified. Release of chloride ions was observed during the enzymatic degradation of these two chlorophenols. Based on the determination of intermediate products and released chloride ions, the degradation pathway that was involved in dehydrogenation , reactive radical intermediates formation, dechlorination , self-coupling and oligomers/polymers formation was proposed. The toxicity of these two chlorophenols and their intermediates was substantially reduced during the enzymatic degradation. The results of this study might present an alternative clean biotechnology for the remediation of 2,4-DCP and 2,4,6-TCP contaminated water matrices.
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2021
·Vol. 22
·期 20
·11087
·
IF 5.924
Guangjie Hu,Yuxuan Xiao,Jie Ying
Coatings are of great significance for irons and steels in regards to the harsh marine environment. Graphene oxides (GO) have been considered as an ideal filler material of epoxy coating. However, the undesired dispersion in the epoxy together with easy agglomeration and stacking remain great problems for practical application of GO composited epoxy coatings. A method that can effectively solve both self-aggregation and poor dispersion of GO is highly desired. Herein, we present a high dispersion strategy of graphene oxides in epoxy by co-decoration of nano-SiO2and silane coupling agent. The co-decorated GO filled epoxy coating exhibits high anti-corrosion performance, including high electrochemical impedance, high self-corrosive potential, low self-corrosive current, and superior electrochemical impedance stability for ten days to Q235 carbon steel. This work displays new possibilities for designing novel coating materials with high performance toward practical marine anti-corrosion applications.Keywords:graphene oxide;epoxy coating;surface decoration;anti-corrosion
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高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Bohan Wang,Guofu Xu,Jiwu Huang,Håkan Engqvist,Wei Xia,Le Fu
Effects of dopants with different valences on the densification behavior and phase composition of a ZrO 2 –SiO 2 nanocrystalline glass-ceramic (NCGC) during pressureless sintering were investigated in this study. The raw powder of Ca 2+ , La 3+ , Ce 4+ and Ta 5+ ions doped ZrO 2 –SiO 2 (referred to as Ca-ZS, La-ZS, Ce-ZS, Ta-ZS, respectively) and pure ZrO 2 –SiO 2 (PZS) sample were synthesized by sol-gel method, followed by pressureless sintering. Compared with the PZS sample, doping of Ca 2+ and La 3+ ions significantly promoted the densification of the NCGCs. The “densification promotion” effect was attributed to the formation of oxygen vacancies and the decrease of SiO 2 viscosity due to doping of aliovalent cations. The dopants with various valences showed significant effects on the phase compositions of the NCGCs during sintering. Doping of Ca 2+ ion accelerated the reaction kinetics between ZrO 2 nanocrystallites and amorphous SiO 2 to yield ZrSiO 4 . The La 3+ ion acted as destabilizer of t-ZrO 2 , which resulted in a rapid tetragonal (t) to monoclinic (m) ZrO 2 phase transformation during sintering, while in the Ta 5+ and Ce 4+ ions doped sample, the phase transformation occurred gradually. All the doping ions increased the lattice parameters and the volume of t-ZrO 2 unit cell, while the effects of the doping ions on the lattice parameters of m-ZrO 2 unit cell were more complex.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Jiahao Wei,Jingtao Bi,Longfei Zhang,Dandan Han,Junbo Gong
Constructing a robust catalytic membrane with simultaneous fast liquid transport and efficient organic pollutant degradation is appealing for efficient organic wastewater treatment. Herein, Fe-doped CoTiO 3 grew uniformly on the SiO 2 fiber membrane to form a catalytic membrane (FCTSM). Benefiting from the great water wettability, FCTSM facilitated fast water transport with low energy consumption and exhibited high physical separation performance (98.4% rejection of oil in the emulsion). The catalytic active sites were fully exposed on membrane surface, which could easily react with peroxymonosulfate and target pollutants. Under the gravity-driven permeation, FCTSM performed decent catalytic degradation property (e.g., 96.3% removal of nimesulide with the flux of 300 L/m 2 ·h) in the presence of peroxymonosulfate. Electron paramagnetic resonance (EPR) spectra and quenching tests found that SO 4 •− and 1 O 2 were involved in pollutant degradation, and the possible degradation pathway of nimesulide was investigated. Besides, the toxicity analyses based on quantitative structure–activity relationship (QSAR) verified the reduced toxicity of degradation products. This work provides an insight into the design of multifunctional membranes and advances the potential applications of heterogeneous catalytic oxidation in environmental remediation.
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高影响因子
Materials
·
2021
·Vol. 14
·期 24
·7853
·
IF 3.623
Yan Luo,Zhongyun Shen,Zhihao Ma,Hongfeng Chen,Xiaodong Wang,Minger Luo,Ran Wang,Jianguo Huang
A silicon dioxide/polytetrafluoroethylene/polyethyleneimine/polyphenylene sulfide (SiO2/PTFE/PEI/PPS) composite filter medium with three-dimensional network structures was fabricated by using PPS nonwoven as the substrate which was widely employed as a cleanable filter medium. The PTFE/PEI bilayers were firstly coated on the surfaces of the PPS fibers through the layer-by-layer self-assembly technique ten times, followed by the deposition of SiO2nanoparticles, yielding the SiO2/(PTFE/PEI)10/PPS composite material. The contents of the PTFE component were easily controlled by adjusting the number of self-assembled PTFE/PEI bilayers. As compared with the pure PPS nonwoven, the obtained SiO2/(PTFE/PEI)10/PPS composite material exhibits better mechanical properties and enhanced wear, oxidation and heat resistance. When employed as a filter material, the SiO2/(PTFE/PEI)10/PPS composite filter medium exhibited excellent filtration performance for fine particulate. The PM2.5 (particulate matter less than 2.5 μm) filtration efficiency reached up to 99.55%. The superior filtration efficiency possessed by the SiO2/(PTFE/PEI)10/PPS composite filter medium was due to the uniformly modified PTFE layers, which played a dual role in fine particulate filtration. On the one hand, the PTFE layers not only increase the specific surface area and pore volume of the composite filter material but also narrow the spaces between the fibers, which were conducive to forming the dust cake quickly, resulting in intercepting the fine particles more efficiently than the pure PPS filter medium. On the other hand, the PTFE layers have low surface energy, which is in favor of the detachment of dust cake during pulse-jet cleaning, showing superior reusability. Thanks to the three-dimensional network structures of the SiO2/(PTFE/PEI)10/PPS composite filter medium, the pressure drop during filtration was low.Keywords:polytetrafluoroethylene;polyphenylene sulfide;filter medium;PM2.5;layer-by-layer self-assembly
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高影响因子
Colloid and Interface Science Communications
·
2021
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IF 4.914
Menghui Wan,Haodong Zhao,Zhihua Wang,Xueyan Zou,Yanbao Zhao,Lei Sun
Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical tool, but how to obtain effective and versatile SERS substrates is still a challenge. Herein, a simple and efficient strategy to prepare SERS substrates with ultra-sensitivity, high stability and wide applicability is presented. SiO 2 nanofibrous membranes were prepared by electrospinning and calcination , and modified with Ag nanoparticles . The results show that Ag nanoparticles decorated on SiO 2 nanofibers evenly and tightly through chemical bonding. The as-prepared membranes exhibit high flexibility and thermostability. The electrospun nanofibrous membranes show an ultra-high sensitivity of 10 −11 mol/L (an enhancement factor of 10 7 ) for small molecules, and the lowest detection limit near to 10 −8 mol/L for pesticides thiram . It is also demonstrated that the substrates remain excellent SERS signal stability even after standing for 60 days (intensity decrease only for 21.7%). More importantly, the as-prepared substrates can be performed for quantitative detection of bacteria.
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高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Jiankang Wang,Taiping Xie,Guokang Han,Quanxi Zhu,Yajing Wang,Yuan Peng,Songli Liu,Zhongping Yao
Cost-effective and low-toxicity of MnO 2 is regarded as a promising alternative to Co-based catalyst for peroxymonosulfate (PMS) activation to degrade recalcitrant organic pollutants. However, the sluggish Mn(IV)/Mn(III) redox cycling and limited specific surface area greatly hampered its wide application. To solve this challenge, a mesoporous γ-Fe 2 O 3 @MnO 2 magnetic catalyst with SiO 2 assistance (s-γ-Fe 2 O 3 @MnO 2 ) was synthesized. Physicochemical characterization confirmed part MnO 2 was coated on γ-Fe 2 O 3 surface while the other existed independently. Furthermore, BET surface area of s-γ-Fe 2 O 3 @MnO 2 was more than two times that of the counterpart without SiO 2 assistance (ws-γ-Fe 2 O 3 @MnO 2 ). s-γ-Fe 2 O 3 @MnO 2 exhibited enhanced PMS activation capacity with 97.6% phenol removal efficiency within 80 min, superior to other samples. Various influencing parameters on phenol oxidation were optimized. Reactive oxygen species (ROS) scavenging experiment and electron paramagnetic resonance (EPR) validated co-existence of hydroxyl radicals (·OH) and sulfate radicals (SO 4 · − ) as well as singlet oxygen ( 1 O 2 ) during PMS activation. However, phenol degradation was a non-radical oxidation process dominated by 1 O 2 . A rational reaction mechanism was proposed. Fe(II) promoted Mn(IV)/Mn(III) redox cycling and the enlarged surface area derived from SiO 2 mediated templating synthesis were responsible for the enhanced phenol degradation. This strategy can give a guidance for synthesis of highly efficient catalyst for sewage remediation.
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高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2021
·
IF 6.291
Jinsong Zhang,Jie Cui,Xinying Li,Xiaohui Hao,Lingli Guo,Hongli Wang,Heliang Liu
Silicosis, a type of lung inflammation and fibrosis caused by long-term inhalation of SiO 2 particles, lacks effective treatment currently. Based on the results of our previous animal experiments, in lungs of SiO 2 -induced silicosis rats, a large number of lymphatic vessels are generated in the early stage of inflammation, which is of great significance for the removal of dust and inflammatory mediators. Here, the molecular mechanism of lymphangiogenesis is further studied. Vascular endothelial growth factor (VEGF-C) is a key pro-lymphangiogenic factor, and its elevated expression is closely related to lymphangiogenesis. In this investigation, we demonstrated that the protein level of VEGF-C was differentially expressed in bronchoalveolar lavage fluid (BALF) and alveolar macrophages (AM) in silicosis patients and healthy controls. We further stimulated human monocyte-macrophage line U937 with SiO 2 , collected the culture supernatants as conditioned medium (CM) for culturing lymphatic endothelial cells (LECs) in vitro, and observed the expression of VEGF-C in the supernatant and its effect on LEC tube formation. The results showed that both CM and single VEGF-C recombinant protein stimulation significantly enhanced LEC proliferation [(1.80 ± 0.18), (1.73 ± 0.16)], chemotaxis [chemotactic cell number (101.40 ± 13.83), (93.40 ± 9.61)], and tube formation [tube number (32.20 ± 7.26), (25.00 ± 6.25); branch number (77.20 ± 6.80), (84.60 ± 7.90)], whereas CM treated with VEGF-CmAb inhibited the proliferation (1.37 ± 0.17), chemotaxis [chemotactic cell number (57.40 ± 8.62)], and tube formation [tube number (7.40 ± 1.85); branch number (47.20 ± 13.44)] of LECs. In addition, CM and VEGF-C can promote the expression of vascular endothelial growth factor receptor 3 (VEGFR-3) and lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) in LECs, which may further mediate lymphangiogenesis by up-regulating the Src/eNOS downstream signaling molecular pathway. This study is the first to clarify the molecular mechanism of pulmonary lymphangiogenesis in silicosis and may point in the direction of eventual treatments, surveillance, and regulation at a molecular level.
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PubMed
高影响因子
COMPOSITES PART B-ENGINEERING
·
2021
·
IF 9.078
Meng Yuan,Meng Zhou,Heqing Fu
Recently, thin, lightweight, wide and strong microwave absorption performance are the main targets for researchers to design high-performance absorbers. A new two-dimension MXene material has attracted significant attention because of its unique hierarchical structure, large specific surface area and special metallic features. However, its improperly high electrical conductivity of MXene causes the bad microwave absorption performance. To meet the needs of practical application, the sandwich-like NiFe 2 O 4 @SiO 2 @MXene nanocomposites were fabricated via multilayered MXene and core-shell NiFe 2 O 4 @SiO 2 nanoparticles. By the synergistic effects from the SiO 2 (transparent medium) improving impedance matching and the two-dimensional laminated MXene increasing conductive loss, the microwave absorption performance of NiFe 2 O 4 @SiO 2 @MXene can be effectively regulated and optimized. As a result, the minimum reflection loss of NiFe 2 O 4 @SiO 2 @MXene reaches −52.8 dB at 11.6 GHz with a thickness of 2 mm, and the maximum effective absorption bandwidth is 7.2 GHz (10.8–18 GHz) covering the whole Ku-band with only a 1.5 mm thickness. It has proved that microcosmic sandwich-like structure design is an efficient approach to achieving excellent microwave absorption performance. The multiple components and unique structure generate heterogeneous interfaces, multiple reflections, polarization features and well-matched impedance. This work provides an insight for rationally constructing hybrid materials with a complex structure in the application of microwave absorption field.
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高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2021
·
IF 3.171
Ke Yang,Shan Zhong,Hairong Yue,Siyang Tang,Kui Ma,Changjun Liu,Kai Qiao,Bin Liang
Pulsed chemical vapor deposition (P-CVD) is a promising technology for the surface modification of TiO 2 particles. For the scale-up application of P-CVD, a custom-designed rotary reactor and corresponding coating process at room temperature was developed in the present work. The obtained SiO 2 -coated TiO 2 particles were characterized by various measures including high-resolution transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, etc . The results illustrated that the SiO 2 films with a thickness of (3.7 ± 0.7) nm were successfully deposited onto the surface of TiO 2 particles. According to the dye degradation tests and acid solubility measurement, the deposited film can effectively inhibit the photocatalytic activity and enhance the weatherability of the TiO 2 particles. Zeta potential measurements showed that the SiO 2 -coated TiO 2 is possible to be stably dispersed in the pH range of 6.9–11.6. The coating process made the whiteness of TiO 2 particles decreased slightly but still sufficient (97.3 ± 0.1) for application. Furthermore, the properties of the TiO 2 particles coated by P-CVD were compared with the particles coated by traditional wet chemical deposition. It is shown that the P-CVD can produce thinner but denser films with better photoactivity suppression performance. The developed coating process within the rotary reactor was proved practically feasible and convenient for the scale-up production of SiO 2 -coated TiO 2 via P-CVD.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 44
·19091-19102
·
IF 3.288
Faguang Ma,Yan Yan,Zhixin Yu,Yilin Wu,Xinlin Liu
The development of molecularly imprinted membranes (MIMs) has promoted applications of membrane-based separation technology, which has shown considerable advantages in water treatment, chemical separation and drug purification. Herein, imitated core–shell PEI@SiO2-based enoxacin-imprinted nanocomposite membranes (SPEIMs) were developed by mixing polyethylenimene-modified silica nanoparticles with polyvinylidene fluoride powder under freezing operation. As a typical and hazardous water pollutant, enoxacin was selected as the template molecule. Morphology and chemical characterizations were explored for an insightful analysis of the obtained membranes. Based on the organic–inorganic hybrid strategy, the as-prepared SPEIMs exhibited superior selectivity towards the target (enoxacin). Satisfactory adsorption performance (55.94 mg g−1), permeability (3.22 for norfloxacin/enoxacin and 7.07 for ciprofloxacin/enoxacin) and regeneration performance (90.31%) were achieved onto SPEIMs. The products and methods obtained in this work would potentially enrich the applications of MIMs in pollution control and biochemical separation.
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高影响因子
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