SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Fang Chengqian,Dai Yimin,Chen Ling,Wang Zhiheng,Lu Qi,Li Yaqi,Cai Ling,Liu Bo,Zhang Yue-Fei,Li Yan,Wan Li
A magnetic Cl − -intercalated Fe 3 O 4 @SiO 2 @MgAl-Cl − LDH nanocomposite has been successfully synthesized by modified one-step salt-assisted coprecipitation process. The Fe 3 O 4 @SiO 2 @MgAl-Cl − LDH nanocomposite was characterized by FTIR, XRD, XPS, SEM, HRTEM, BET and VSM. The results showed that the Fe 3 O 4 @SiO 2 @MgAl-Cl − LDH particles possessed core (Fe 3 O 4 @SiO 2 ) shell (Cl − -LDH) structures and magnetic properties, and Cl − anions were successfully introduced into LDH interlayers. The unique intercalated structure with week interlayer interaction of Fe 3 O 4 @SiO 2 @MgAl-Cl − LDH provide efficient adsorption of methyl orange (MO), Congo red (CR) and methyl blue (MB), leading to its superior performance with much higher uptake capability with the maximum adsorption capacity of MO, CR and MB reaching 733 mg·g −1 , 910 mg·g −1 and 385 mg·g −1 , respectively. The adsorption process could be well described by pseudo-second-order model for MO, CR and MB. The experimental data of MO and CR could be fitted better with Freundlich model, while that of MB were fitted better with Langmuir model. The adsorption process was spontaneous and exothermic for MO and MB, while spontaneous and endothermic for CR. Moreover, the adsorbent exhibits excellent stability and reusability in the regeneration cycle, and a process called ‘‘post-processing step” is proposed to effectively improve the dye removal ability of the adsorbent in reuse. This study puts forward a new thought for the development of high-performance LDH adsorbents with mesoporous and Cl − intercalation structure for the efficient and rapid removal of dyes.
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高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 47
·72058-72073
·
IF 5.19
Gao Jingqing,Liu Xiaobang,Ren Peng,Gao Jianlei,Chen Yong,Chen Zhijun
The novel iron-based reductive particles, functionalized with amino and carboxylic functional groups, were synthesized to remove Cr(VI) and Cd(II) ions from aqueous solutions. The morphological structure and surface functional groups of new composites were characterized with SEM, XRD, FTIR, BET, and other techniques. The influence of pH, initial concentration, adsorbent dosing, and temperature on removal efficiencies were explored by batch experiments. The adsorption capacity of Cr(VI) and Cd(II) increased by 159.95% and 76.60%, respectively, compared with Fe 0 , reaching 47.638 and 62.047 mg/g. EDS and XPS analysis showed most of Cr(VI) was reduced to Cr(III) and precipitated as ferrochrome oxide, and Cd(II) was mainly precipitated as hydroxide. Reduction-precipitation and complexation may predominate in the removal process of Cr(VI), which fitted well with Langmuir and Freundlich models and pseudo-second-order kinetics. While hydrolysis and complexation may prevail for Cd(II), which was suited with Langmuir model and pseudo-second-order kinetics. Having good magnetic properties, the A/C-Fe@SiO 2 particles exhibited excellent reusable stability after four times regeneration experiments, promising a prospect for in-situ remediations of groundwater contaminated by Cr(VI) and Cd(II).
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PubMed
高影响因子
CARBON
·
2022
·
IF 11.307
Xueyan Wang,Zhong Liu,Xianfeng Liu,Ying Su,Jin Wang,Tingting Fan,Xin Ning,Seeram Ramakrishn,Yun-Ze Long
The accumulative disasters about oil spills and industrial emissions create increasingly environmental problems, and high-performance absorbent materials have attracted wide attention to providing available solution. Herein, polyvinylidene fluoride/SiO 2 @graphene oxide (PVDF/SiO 2 @GO) aerogels were prepared by cross-linking of the electrospun PVDF/SiO 2 nanofibers and GO skeleton. By changing the content of SiO 2 nanoparticles in the PVDF nanofibers, the porosity and surface roughness of the composite aerogels could be controlled. Compared with PVDF@GO aerogel, the PVDF/SiO 2 @GO (PSG) aerogels had higher mechanical properties and hydrophobicity . And, the PSG-2 aerogel (1 wt% SiO 2 contained in nanofibers) exhibited stable structure, excellent oil absorption capacity (129–264 g g −1 ), great flame retardancy and reusability . After being pretreated with strong acid and alkali, it remained strong hydrophobicity, indicating it possessed excellent chemical resistance. More importantly, it could also separate oil-water mixture by gravity under harsh environment (strong acid/alkali), which exhibited excellent separation performance with flux of 42402 L m −2 h −1 (chloroform/water mixture) and separation efficiency of 99.96%. Moreover, it could clean up viscous crude oil rapidly by photothermal effect, and the crude oil absorption time of heated PSG-2 was reduced by 99.65%. The PSG aerogels provide a new choice for efficient and continuous harsh environmental oil-water separation and crude oil absorption.
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高影响因子
CATALYSIS LETTERS
·
2022
·Vol. 152
·期 10
·3046-3057
·
IF 2.936
Yu Pei,Jiang Junxiang,Chen Can,Wang Zhong,Wang Da,Li Guangci,Li Xuebing
Catalytic selective hydrogenation of esterified malic acid to produce 1,2,4-butanetriol (1,2,4-BT) using H 2 as the reducing reagent suffers from the low 1,2,4-BT selectivity. Here, Ru/SiO 2 catalyst was employed for selective hydrogenation of dimethyl malate (DM) to produce 1,2,4-BT, which gave abnormal high DM conversion (100%) and 1,2,4-BT selectivity (92.4%) in aqueous solvent at 363 K, especially, the 1,2,4-BT yield even is higher than the optimal catalyst reported (Ru-Re, 79.8%). The reaction pathways for the DM hydrogenation on Ru/SiO 2 were also proposed, suggesting that extremely high 1,2,4-BT selectivity require for the much high hydrogenation rates at low temperatures, where side-reaction transesterification rates are relatively low. The extremely high hydrogenation activity and 1,2,4-BT selectivity on Ru/SiO 2 in aqueous solvent at low temperatures arise from that H 2 O may coordinate to Ru 2+ and prevent the reduction of Ru 2+ to Ru under high H 2 pressure. Ru/SiO 2 surface presents abundant Ru 2+ in aqueous solvent, can activate H 2 through heterolytic cleavage mode to form hydride, which can significantly increase hydrogenation rates of C = O groups at low temperatures. In addition, the activity and 1,2,4-BT selectivity on Ru/SiO 2 catalyst only reduced by 2.3% and 2.6%, respectively over a period of 550 h. Graphical Abstract
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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
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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PubMed
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
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Xuewu Li,Shaomeng Du,Chenghu Ma,Tian Shi,Wei Qi,Hejie Yang
Improving the corrosion resistance of widely used Al alloys is important for expanding their industrial and marine applications. Structural fragility and preparation cost have always been key factors for restricting anticorrosive application of extensively-reported superhydrophobic surface. In order to try and fight that, combining with polyurethane (PU) adhesion agent, 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) was encapsulated around nano-SiO 2 ceramics for robust coating in place of conventional structure preparation strategy on Al alloy surface. Such low-cost one-step air-spraying SiO 2 @PFDTES@PU coating was prepared by 0.03 g nano-SiO 2 ceramics addition, 100 μL PFDTES and 0.25 g PU with the highest water contact angle of 168.34° ± 2.72°, a rolling angle of 4.02° ± 2.08°, and a propylene glycol oil contact angle of 156.52° ± 3.35°. FE-SEM, laser confocal microscopy, EDS and XPS were used to investigate micro-nano morphology and chemical composition of the coating. Meanwhile, the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements showed that as-prepared coating exhibited larger capacitive arc diameter, enhanced charge transfer resistance, larger |Z| 0.01Hz value, positive shifting E corr and significantly reduced I corr , thus demonstrating a significantly improved corrosion resistance. In addition, sandpaper friction experiment was used to evaluate the mechanical stability of the fabricated superhydrophobic coating. Ultimately, its resistance to solid/liquid contamination and self-cleaning ability were also systematically assessed. This work provides strong technical supports for industrial and marine applications for such low-cost, wear-resistant and anti-corrosion coating.
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高影响因子
INORGANIC CHEMISTRY
·
2023
·
IF 4.6
Weihao Zhao,Jinxin Fan,Yuan Tian,Cheng Wang
Lithium metal batteries have become one of the most promising rechargeable batteries due to the ultrahigh theoretical specific capacity of the Li metal anode. However, the Li dendrite growth and volume change of the Li metal anode during repeated Li plating–stripping cycles restrict the practical viability. Herein, a unique lithiophilic gradient structure of uniformly incorporating Ag nanoparticles into a three-dimensional (3D) nanofiber framework with amorphous SiO2 and TiO2 hybrids was prepared by an electrospinning process and used as a multifunctional interlayer between the pristine separator and Li metal foil. The 3D framework not only possesses excellent flexibility but also alleviates volume changes, which can withstand massive Li loading and promote uniform Li+ distribution. In addition, the 3D lithiophilic gradient structure allows for regulable Li+ flux and suppresses Li dendrite growth. Impressively, the Li||Li symmetric batteries with Ag@SiO2–TiO2 interlayers exhibit a prolonged lifespan of 1500 h at 0.5 mA cm–2 for 0.5 mAh cm–2. The full cells coupled with the Ag@SiO2–TiO2 interlayer show a capacity retention rate of 94.6% after 1000 cycles and a high rate capability. This work provides promising guidance for the design of a gradient-distributed lithiophilic structure toward an ultrastable Li metal anode.
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PubMed
高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Yicheng Ye,Qiaohong Zhang,Dezhong Xie,Chen Chen,Fan Li,Hu Wang,Shun Zhang,Wei Zhang
Ethanol-based drinks and disinfectants are widely consumed around the world. Acetaldehyde (AA) is the main impurity in ethanol, which is also a representative volatile organic compound (VOC). Increased attention should be paid to the potential harm caused by AA in ethanol due to the significant increase of AA exposure even in nondrinkers. With Ag nanoparticles (NPs) being supported on the phenyl group-modified silica (Ag/Ph-SiO2) as the catalyst, which was prepared by a simple one-pot reverse-phase microemulsion method, a catalytic hydrogenation removal strategy has been illustrated in the present work to ultradeeply remove AA in ethanol. The introduction of phenyl groups facilitated the distribution of Ag NPs, the formation of the pore structure, and the improvement of the surface affinity to AA molecules, which are beneficial for the adsorption and conversion of AA in ethanol. The AA content in ethanol could be controlled to be below 0.1 ppm at 90 °C in 5 h under 3 MPa H2 pressure. The safety of ethanol-based products is believed to be greatly improved with the present technology.
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高影响因子
Energies
·
2023
·Vol. 16
·期 22
·7523
·
IF 3.2
Jiani Hu,Meilong Fu,Yuxia Zhou,Fei Wu,Minxuan Li
The purpose of this study is to investigate the use of SiO2nanoparticles in assisting with surfactants and polymers for tertiary oil recovery, with the aim of enhancing oil recovery. The article characterizes the performance of SiO2nanoparticles, including particle size, dispersion stability, and zeta potential, evaluates the synergistic effects of nanoparticles with alpha-olefin sulfonate sodium (AOS) surfactants and hydrolyzed polyacrylamide (HPAM) on reducing interfacial tension and altering wettability, and conducts core flooding experiments in rock cores with varying permeabilities. The findings demonstrate that the particle size decreased from 191 nm to 125 nm upon the addition of SiO2nanoparticles to AOS surfactant, but increased to 389 nm upon the addition of SiO2nanoparticles to HPAM. The dispersibility experiment showed that the SiO2nanoparticle solution did not precipitate over 10 days. After adding 0.05% SiO2nanoparticles to AOS surfactant, the zeta potential was −40.2 mV, while adding 0.05% SiO2nanoparticles to 0.1% HPAM resulted in a decrease in the zeta potential to −25.03. The addition of SiO2nanoparticles to AOS surfactant further reduced the IFT value to 0.19 mN/m, altering the rock wettability from oil-wet to strongly water-wet, with the contact angle decreasing from 110° to 18°. In low-permeability rock core oil displacement experiments, the use of AOS surfactants and HPAM for enhanced oil recovery increased the recovery rate by 24.5% over water flooding. The recovery rate increased by 21.6% over water flooding in low-permeability rock core experiments after SiO2nanoparticles were added and surfactants and polymers were utilized for oil displacement. This is because the nanoparticles blocked small pore throats, resulting in increased resistance and hindered free fluid flow. The main causes of this plugging are mutual interference and mechanical entrapment, which cause the pressure differential to rise quickly. In high-permeability rock core oil displacement experiments, the use of AOS surfactants and HPAM for oil recovery increased the recovery rate by 34.6% over water flooding. Additionally, the recovery rate increased by 39.4% over water flooding with the addition of SiO2nanoparticles and the use of AOS surfactants and HPAM for oil displacement. Because SiO2nanoparticles create wedge-shaped structures inside highly permeable rock cores, they create structural separation pressure, which drives crude oil forward and aids in diffusion. This results in a comparatively small increase in pressure differential. Simultaneously, the nanoparticles change the rock surfaces’ wettability, which lowers the amount of crude oil that adsorbs and improves oil recovery.Keywords:SiO2nanoparticles;enhanced oil recovery;performance characterization;oil displacement experiment
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高影响因子
CARBON
·
2023
·
IF 10.9
Guodong Shi,Jian Song,Xiaoxiao Tian,Tongtong Liu,Zhanjun Wu
Graphene oxide (GO) is an ideal reinforcement for improving mechanical properties of epoxy (EP) and reducing its coefficient of thermal expansion (CTE). However, the poor interfacial interaction between GO and polymer matrix seriously hinders the reinforcing effect of GO. To improve their interface, we first functionalized GO with flexible polyetheramine (PEA) and f-SiO 2 rigid nanoparticles, obtaining PEA-GO and SiO 2 -PEA-GO hybrids, respectively. Then the PEA-GO and SiO 2 -PEA-GO were incorporated into EP to obtain nanocomposites with flexible interphases and rigid-flexible interphases, respectively. The interfaces were tuned by two PEA molecules (D230 and D2000) with different chain lengths. The effects of the different interface structures on the mechanical properties and CTE of the GO/EP nanocomposites with a 0.25 wt% filler loading were investigated. It was found that the effects of SiO 2 -PEA-GO on strengthening and toughening EP matrix and on reducing its CTE were much better than those of PEA-GO, because the rigid-flexible interfaces provided higher bonding strength and better energy dissipation mechanisms than the flexible interfaces. Moreover, the D230-GO/EP nanocomposite containing shorter PEA (D230) molecules exhibited higher strength but lower toughness and CTE than the D2000-GO/EP nanocomposite. However, the SiO 2 -D2000-GO/EP nanocomposite showed greater strength, toughness and CTE than the SiO 2 -D230-GO/EP nanocomposite. This indicated that the longer PEA molecules in rigid-flexible interphases produced higher improvement in strength and toughness but smaller decreases in CTE. This work provides a promising strategy of constructing an adjustable flexible-rigid interfacial structure and opens an avenue for developing GO/EP nanocomposites with high mechanical properties and low CTE.
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高影响因子
危险品化学品经营许可证（带存储）