JOURNAL OF MOLECULAR LIQUIDS
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2019
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IF 4.561
Yang Wang,Si Sun,Lin Shi,Pengcheng Gao,Yingying Wei,Chuan Zhang,Yong Jiang
A facile and energy-efficient synthesis of Fe 3 O 4 @SiO 2 -PHEMA complex and its application as adsorbent for removal of Cu 2+ from aqueous solution were investigated. Fe 3 O 4 @SiO 2 -PHEMA was synthesized by mixing Fe 3 O 4 @SiO 2 and HEMA monomer and then initiating the polymerization of HEMA monomer by H 2 O 2 under Fe 2+ catalyzing at room temperature . As adsorbent, the maximum sorption capacity of Fe 3 O 4 @SiO 2 -PHEMA for Cu 2+ was calculated to be 20.7 mg/g at pH 6.0. And the efficient enrichment of Cu 2+ on Fe 3 O 4 @SiO 2 -PHEMA depended on its multiple carbonyl groups and the electrostatic interaction between carboxyl groups and Cu 2+ . The carboxyl groups were from slow hydrolysis of partial ester bonds of PHEMA under acidic conditions. The possible hydrolysis process of ester bonds was facilitated to avoid sorption capacity of Cu 2+ decreasing caused by other ions sorption (like Fe 2+ ) during the synthesis of the adsorbent. The adsorption of Cu 2+ on Fe 3 O 4 @SiO 2 -PHEMA coincided with Langmuir model. The Fe 3 O 4 @SiO 2 -PHEMA had good dispersity in water and it could be easily collected from wastewaters by a magnet. The results showed that Fe 3 O 4 @SiO 2 -PHEMA was a promising adsorbent in wastewater treatment.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Yao Fu,Jian Li,Pengzhen Li,Huajie Tao,Xianfu Luo,Dongjian Wang,Yiting Shan,Hongqing Zhou
In this work, the titanate coupling agent KR-TTS was used in tape casting of CaO–B 2 O 3 –SiO 2 (CBS) glass-ceramics to obtain a high-performance dielectric tape. The functional group ((RO) m ) of KR-TTS could directly react with the hydroxyl (–OH) of the CBS powders, which made the feature of powders from hydrophilicity into hydrophobicity . The modification mechanism of the modifier KR-TTS was illuminated by infrared absorption spectrum and contact angle of powders with modifier KR-TTS. The optimum amount of KR-TTS was determined by the rheological properties of suspensions, the density and the tensile strength of the green samples, the density and dielectric properties of the sintering samples sintered at 835 °C. The surface modification of CBS glass-ceramic by KR-TTS has made a substantial breakthrough in improving the densification and the mechanical performance of the green tapes. When the amount of KR-TTS was 1.0 wt%, the stability of slurry and the properties of the green samples had been greatly improved. The density of the green samples with 1.0 wt% KR-TTS reached 1.59 g/cm 3 and the tensile strength of the green samples reached 2.43 MPa. The sintering sample with 1.0 wt% KR-TTS realized sintering densification and performed better dielectric properties. The sintering density reached to 2.51 g/cm 3 . The permittivity and dielectric loss were ε r = 5.92 and tanδ = 13 × 10 −4 at 10 GHz.
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PROGRESS IN ORGANIC COATINGS
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2022
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IF 6.206
Bo Shu,Zhilang Liu,Zhaoqing Liu,Pengsong Li,Xin Li,Shaoheng Yang,Huangwei Chen,Jiqiang Liu,Zhuohong Yang,Yang Hu
Graphene oxide (GO) acted as an inorganic filler has attracted great attention in the construction of polymer-based composite coating film. Nevertheless, the high surface area, obvious van der Waals forces, and abundant hydrophilic groups of GO result in its poor dispersion behavior and compatibility in hydrophobic polymer , which greatly limits its widespread practical application. To solve the above issue, we have prepared SiO 2 -decorated GO (GO-SiO 2 ) nanoparticles using the sol-gel hydrolysis method. The FTIR, Raman spectra, XPS and SEM analysis displayed that GO-SiO 2 nanoparticles were successfully constructed and the SiO 2 nanoparticles are covalently grafted onto GO sheet surfaces. Moreover, the GO-SiO 2 nanoparticles are further employed as inorganic fillers into the non-solvent UV-curable castor oil-based polyurethane acrylate (COPUA) systems for the preparation of composite coating films. Herein, the GO-SiO 2 nanoparticles can be uniformly dispersed in hydrophobic COPUA-based coating precursor, and have favorable compatibility with COPUA resin. The incorporation of GO-SiO 2 nanoparticles into the coating film matrix would slightly decrease the gel content of coating films (all gel contents are above 91.5 %) while improving the hydrophobic property of coating films. Furthermore, the thermal stability and mechanical performance of coating films have reasonably enhanced trends by the incorporation of GO-SiO 2 nanoparticles. The prepared coating films display favorable acid, alkali, and solvent resistance , and the high content of GO-SiO 2 nanoparticles is beneficial to aggrandize the anticorrosion performance of coating films. This work provides a universal approach to modify GO sheets and construct multifunctional modified GO/polyurethane composite film for coating application.
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FUEL
·
2022
·
IF 8.035
Wenxiu Luo,Guo Li,Wei Cheng,Yi Wang
Carbon materials deriving from biomass wastes have become particularly attractive and are broadly in line with the concepts of green chemistry because of their cost efficiency and their properties as abundant natural resources . However, it still remains a big challenge to seek suitable synthetic strategies and effective approaches to regulate the size/surface dependent properties for preparing high catalytic performance of biomass-derived carbons. In this work, for the first time, we demonstrate that the silicon dioxide (SiO 2 ) modified carbonaceous materials from inner layer of pomelo peel (IPPC-SiO 2 ), which can act as an excellent support for small-size and well-dispersed Rh nanoparticles (NPs). The as-synthesized Rh/IPP-SiO 2 catalyst performs excellently for catalytic ammonia borane dehydrogenation reactions. The turnover frequency (TOF) value of ammonia borane hydrolysis is 1295 mol H 2 min −1 (mol Rh) -1 and the activation energy is 26.1 kJ mol −1 , indicating that the catalytic efficiency of the resulting composites is superior to that of most noble-metal catalysts reported. Based on these experimental results, a proposed mechanistic analysis of the SiO 2 regulating biomass carbon is presented as an effective support of Rh nanoparticles for optimizing catalytic ammonia borane dehydrogenation.
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CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Yanlong Wang,Jiang Xu,Kun Yang,Daohui Lin
Water scarcity is one of the most pressing global challenges and limits economic and social development. Multiple processes of current technologies for water purification are needed to meet water quality objectives due to their contaminant-specific removal capability. Here, we developed Fe 0 @SiO 2 @CaO 2 nanocomposite with three layers of core–shell structure that could achieve an array of water contaminants removal by oxidation, reduction, and flocculation. >99 % of 50 mg/L tetracycline, 20 mg/L pentachlorophenol, 450 mg/L Cd(Ⅱ), 20 mg/L Cr(Ⅵ), or 80 mg/L P (in form of PO 4 3− ) was removed by 2 g/L Fe 0 @SiO 2 @CaO 2 in 24 h. Moreover, Fe 0 @SiO 2 @CaO 2 (2 g/L) showed an excellent performance in turbidity removal (239 mg/L kaolinite suspension, removal rate > 99 %) and water decolorization (50 mg/L humic acid, removal rate > 93 %). Cd(II) and Cr(VI) could be reduced to Cd(0) and Cr(III), respectively, through electronic reduction reactions using Fe 0 and •H, which is formed during the reaction Fe 0 + 2H + →2•H + Fe 2+ ; Cd(Ⅱ) and the formed Cr(III) could coprecipitate with the formed orthosilicic acid and OH − . The removal of P was mainly resulted from the coordination with released Ca 2+ and iron compounds. Charge neutralization by nanocomposite and coagulation with the products from nanocomposite transformation were responsible for the kaolinite removal. Reduction by •H and Fe 0 , oxidation by •OH derived from the Fenton reaction, and/or coagulation accounted for the organic contaminant removal. This work provides a novel material that can be used to simultaneously remove a range of contaminants in wastewater treatment.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
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IF 5.2
Siqin He,Bin Xu,Ying Liu,Xiaoshuang Yin,Wenzhong Yang,Yun Chen
Polyaminoamide (PAMAM) dendrimers with different generations from 1 G to 5 G were grafted on magnetic core-shell Fe 3 O 4 -SiO 2 composite particles , respectively. Using Fe 3 O 4 as a magnetic center and SiO 2 as the connecting layer, the PAMAM dendrimers with amino functional groups were modified on SiO 2 successfully, while laccase was immobilized to the surface of Fe 3 O 4 -SiO 2 -PAMAM x by covalent cross-linking using amide bond. Under the optimal conditions, the loading capacity of laccase reached 65.5 mg/g, and about 62.8 % of its initial activity of free laccase was reserved. Immobilized laccase degradated 2,4-dichlorophenol (2,4-DCP) with a degradation ratio of 91.5 % after 24 h. The degradation ratio of 82.9 % was maintained after 5 cycles of the operation, and when enhanced to the 10 cycles degradation, the degradation rate was still remained close to 80 %. Compared with free laccase, the comprehensive stability of immobilized laccase was improved significantly, and it displayed the excellent catalytic degradation ability for 2,4-DCP.
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Energies
·
2023
·Vol. 16
·期 22
·7523
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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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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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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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ChemCatChem
·
2023
·Vol. 15
·期 22
·e202300967
·
IF 4.5
Ting Li,Yuhao Tian,Xiaoli Yan,Weijie Cai
Graphical CO 2 Reforming : Transition metal-based SiO 2 -Ni@CeO 2 catalyst with typical core@shell structure exhibited the better activity/stability in CO 2 reforming with ethanol reaction compared to SiO 2 -Cu@CeO 2 sample. It is of great significance to design the high-performance catalysts with good anti-sintering and coke-resistance properties which can efficiently convert undesirable greenhouse gas CO 2 with bio-ethanol into high value-added syngas. To be addressed this issue, a series of SiO 2 -M@CeO 2 (M: Cu, Ni) catalysts with typical core@shell structure were prepared via a strong electrostatic adsorption technique. Interestingly, Ni-based catalyst exhibited the higher activity towards ethanol dry reforming at the relatively low temperature. Meanwhile, SiO 2 -Ni@CeO 2 catalyst presented good stability after a 50 h tests while a serious deactivation occurred for SiO 2 -Cu@CeO 2 within 20 h reaction due to heavy carbon deposition and reactor blockage. Herein, the higher catalytic performance of SiO 2 -Ni@CeO 2 catalyst compared to SiO 2 -Cu@CeO 2 sample was attributed to the combination effect of its mesoporous structure, higher Ni dispersion as well as stronger Ni-Ce interaction as depicted by BET, TEM, XPS, H 2 -TPR and XRD findings. This work might provide meaningful information to other reforming processes involving coke formation and active metal sintering problems.
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APPLIED ORGANOMETALLIC CHEMISTRY
·
2020
·Vol. 34
·期 8
·e5707
·
IF 3.14
Laiyun Zhou,Mingliang Wang,Kaixuan Wang,Tiantian Wen,Lanzhi Wang
Fe 3 O 4 @SiO 2 -CeCl 3 catalyzed chemoselective synthesis of functionalized 3-substituted-1,5-benzodiazepines via one-pot multicomponent and domino reactions has been developed. During the one-pot synthesis process, one new cycle and four new bonds (one C–C, two C–N and one C=C) were constructed by the nucleophilic addition and eliminate reaction (dehydration etc.) process, intramolecular proton transfer and cyclization process. The major advantages of the present method are good to excellent yields, shorter reaction time, simple experimental procedure, easy work up, mild reaction conditions, recyclability of the catalyst and ability to tolerate a variety of functional groups which gives economical as well as ecological rewards.
研究领域:
有机化学
·
药物化学
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Rujing Xue,Yina Zhuge,Guoliang Liu,Fujuan Liu
ZIF-L, a metal-organic framework (MOF) material, has a two-dimensional (2D) foliation, a large specific surface area, excellent thermal stability and CO 2 adsorption performance, respectively. In this work, in order to further improve the thermal insulation performance of SiO 2 aerogel composite fabrics , ZIF-L powder was first prepared as a reinforcing particle, and then added to silica aerogel. Finally, SiO 2 /AF/ZIF-L composites were obtained by solution impregnation method. The influence of different ZIF-L concentrations on the insulation performance of composites and their influencing factors were studied. Furthermore, these composites were fully characterized using BET measurement, Instron 5967, precision transient thermal performance tester, infrared thermal imager, insulation performance test, thermogravimetric analyzer, and dynamic thermomechanical analyzer. The results showed that 0.12% SiO 2 /AF/ZIF-L composites had excellent thermal insulation performance, with a thermal conductivity as low as 0.029 W/(m·K). In addition, SiO 2 /AF/ZIF-L composites fabricated by atmospheric drying method had the best thermal insulation performance under the conditions of gel time of 24 h, hydrolysis time of 5 h, and polycondensation pH value of 5–6.
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危险品化学品经营许可证（带存储）