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A novel strategy for the construction of silk fibroin–SiO composite aerogel with enhanced mechanical

《化学科学与工程前沿（英文）》 2023年 第17卷 第3期   页码 288-297 doi: 10.1007/s11705-022-2222-7

摘要： The practical application of silica aerogels is an enormous challenge due to the difficulties in improving both mechanical property and thermal insulation performance. In this work, silk fibroin was used as scaffold to improve the mechanical property and thermal insulation performance of silica aerogels. The ungelled SiO2 precursor solution was impregnated into silk fibroin to prepare silk fibroin–SiO2 composite aerogels via sol−gel method followed by freeze-drying. By virtue of the interfacial hydrogen-bonding interactions and chemical reactions between silk fibroin and silica nanoparticles, SiO2 was well-dispersed in the silk fibroin aerogel and composite aerogels exhibited enhanced mechanical property. By increasing the loading of silk fibroin from 15 wt % to 21 wt %, the maximum compressive stress was enhanced from 0.266 to 0.508 MPa when the strain reached 50%. The thermal insulation performance of the composite aerogels was improved compared with pure silica aerogel, as evidenced that the thermal conductivity was decreased from 0.0668 to 0.0341 W∙m‒1∙K‒1. Moreover, the composite aerogels exhibited better hydrophobicity and fire retardancy compared to pure silica aerogel. Our work provides a novel approach to preparing silk fibroin–SiO2 composite aerogels with enhanced mechanical property and thermal insulation performance, which has potential application as thermal insulation material.

关键词： silica aerogel     silk fibroin     impregnation     thermal insulation     mechanical property    

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Effect of sodium bicarbonate solution on methyltrimethoxysilane-derived silica aerogels dried at ambient

Yujing Liu, Xiao Han, Balati Kuerbanjiang, Vlado K. Lazarov, Lidija Šiller

《化学科学与工程前沿（英文）》 2021年 第15卷 第4期   页码 954-959 doi: 10.1007/s11705-020-2028-4

摘要： Here we present an economical ambient pressure drying method of preparing monolithic silica aerogels from methyltrimethoxysilane precursor while using sodium bicarbonate solution as the exchanging solvent. We prepared silica aerogels with a density and a specific surface area of 0.053 g∙cm and 423 m ∙g , respectively. The average pore diameter of silica aerogels is 23 nm as the pore specific volume is 1.11 cm ∙g . Further, the contact angle between water droplet and the surface of silica aerogels in specific condition can be as high as 166°, which indicates a super-hydrophobic surface of aerogels.

关键词： silica aerogel     methyltrimethoxysilane     solvent exchange     sodium bicarbonate     trimethylchlorosilane     ambient pressure drying    

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Fabrication of cellulose aerogel from wheat straw with strong absorptive capacity

Jian LI,Caichao WAN,Yun LU,Qingfeng SUN

《农业科学与工程前沿（英文）》 2014年 第1卷 第1期   页码 46-52 doi: 10.15302/J-FASE-2014004

摘要： An effectively mild solvent solution containing NaOH/PEG was employed to dissolve the cellulose extracted from the wheat straw. With further combined regeneration process and freeze-drying, the cellulose aerogel was successfully obtained. Scanning electron microscope, X-ray diffraction technique, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller were used to characterize this cellulose aerogel of low density (about 40 mg·cm ) and three-dimensional network with large specific surface area (about 101 m ·g ). Additionally, with a hydrophobic modification by trimethylchlorosilane, the cellulose aerogel showed a strong absorptive capacity for oil and dye solutions.

关键词： cellulose aerogel     absorptive capacity     waste wheat straw     freeze-drying    

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Simple fabrication of carboxymethyl cellulose and κ-carrageenan composite aerogel with efficient performance

《环境科学与工程前沿（英文）》 2022年 第16卷 第10期 doi: 10.1007/s11783-022-1568-x

摘要：

● A composite aerogel was simply obtained to remove various fluoroquinolones (FQs).

关键词： Composite aerogel of carboxymethyl cellulose and κ-carrageenan     Fluoroquinolone antibiotics     Adsorption performance     Coexisting substances     Adsorption mechanism     Reusability    

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Hierarchically porous cellulose nanofibril aerogel decorated with polypyrrole and nickel-cobalt layered

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1593-1607 doi: 10.1007/s11705-023-2348-2

摘要： With increasing emphasis on green chemistry, biomass-based materials have attracted increased attention regarding the development of highly efficient functional materials. Herein, a new pore-rich cellulose nanofibril aerogel is utilized as a substrate to integrate highly conductive polypyrrole and active nanoflower-like nickel-cobalt layered double hydroxide through in situ chemical polymerization and electrodeposition. This ternary composite can act as an effective self-supported electrode for the electrocatalytic oxidation of glucose. With the synergistic effect of three heterogeneous components, the electrode achieves outstanding glucose sensing performance, including a high sensitivity (851.4 µA·mmol−1·L·cm−2), a short response time (2.2 s), a wide linear range (two stages: 0.001−8.145 and 8.145−35.500 mmol·L−1), strong immunity to interference, outstanding intraelectrode and interelectrode reproducibility, a favorable toxicity resistance (Cl‒), and a good long-term stability (maintaining 86.0% of the original value after 30 d). These data are superior to those of some traditional glucose sensors using nonbiomass substrates. When determining the blood glucose level of a human serum, this electrode realizes a high recovery rate of 97.07%–98.89%, validating the potential for high-performance blood glucose sensing.

关键词： cellulose nanofibril     aerogel     nickel-cobalt layered double hydroxide     polypyrrole     nonenzymatic glucose sensor    

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Optimizing the compressive strength of concrete containing micro-silica, nano-silica, and polypropylene

Fatemeh ZAHIRI, Hamid ESKANDARI-NADDAF

《结构与土木工程前沿（英文）》 2019年 第13卷 第4期   页码 821-830 doi: 10.1007/s11709-019-0518-6

摘要： Many studies have evaluated the effects of additives such as nano-silica (NS), micro-silica (MS) and polymer fibers on optimizing the mechanical properties of concrete, such as compressive strength. Nowadays, with progress in cement industry provides, it has become possible to produce cement type I with strength classes of 32.5, 42.5, and 52.5 MPa. On the one hand, the microstructure of cement has changed, and modified by NS, MS, and polymers; therefore it is very important to determine the optimal percentage of each additives for those CSCs. In this study, 12 mix designs containing different percentages of MS, NS, and polymer fibers in three cement strength classes(CSCs) (32.5, 42.5, and 52.5 MPa) were designed and constructed based on the mixture method. Results indicated the sensitivity of each CSCs can be different on the NS or MS in compressive strength of concrete. Consequently, strength classes have a significant effect on the amount of MS and NS in mix design of concrete. While, polymer fibers don’t have significant effect in compressive strength considering CSCs.

关键词： mixture method     compressive strength     nano-silica     micro-silica     polypropylene fibers    

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Dispersion of “guava-like” silica/polyacrylate nanocomposite particles in polyacrylate matrix

QI Dongming, YANG Lei, WU Minghua, SHAO Jianzhong, BAO Yongzhong

《化学科学与工程前沿（英文）》 2008年 第2卷 第2期   页码 127-134 doi: 10.1007/s11705-008-0033-0

摘要： A series of “guava-like” silica/polyacrylate nanocomposite particles with close silica content and different grafting degrees were prepared via mini-emulsion polymerization using 3-(trimethoxysilyl)propyl methacrylate (TSPM) modified silica/acrylate dispersion. The silica/polyacrylate composite particles were melt-mixed with unfilled polyacrylate (PA) resin to prepare corresponding silica/polyacrylate molded composites and the dispersion mechanism of these silica particles from the “guava-like” composite particles into polyacrylate matrix was studied. It was calculated that about 110 silica particles were accumulated in the bulk of every silica/polyacrylate composite latex particle. Both the solubility tests of silica/polyacrylate composite latex particles in tetrahydrofuran (THF) and the section transmission electron microscope (TEM) micrographs of silica/polyacrylate molded composites indicated that the grafting degree of silica particles played a crucial role in the dispersion of silica/polyacrylate composite particles into the polyacrylate matrix. When the grafting degree of polyacrylate onto silica was in a moderate range (ca. 20%–70%), almost all of silica particles in these “guava-like” composite particles were dispersed into the polyacrylate matrix in a primary-particle-level. However, at a lower grafting degree, massive silica aggregations were found in molded composites because of the lack of steric protection. At a greater grafting degree (i.e., 200%), a cross-linked network was formed in the silica/polyacrylate composite particles, which prevented the dispersion of composite particles in THF and polyacrylate matrix as primary particles.

关键词： silica/polyacrylate composite     cross-linked network     –70     guava-like     TEM    

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Enhanced activation of persulfate using mesoporous silica spheres augmented Cu–Al bimetallic oxide particles

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1581-1592 doi: 10.1007/s11705-023-2327-7

摘要： Herein, Cu–Al bimetallic oxide was synthesized and mixed with mesoporous silica spheres via a simple hydrothermal method. The prepared sample was then analyzed and employed to activate potassium peroxydisulfate for bisphenol A removal. Based on the results of X-ray diffraction, scanning electron microscopy, and energy dispersion spectroscopy, Cu–Al bimetallic oxide was determined as CuO-Al2O3, and mesoporous silica spheres were found around the these particles. At 30 min, a bisphenol A degradation level of 90% was achieved, and it remained at over 60% after five consecutive cycles, indicating the catalyst’s superior capacity and stability. In terms of removal performance, the radical pathway (including SO4•‒, OH •, and O2•‒) and singlet oxygen (1O2) played minor roles, while electron migration between bisphenol A, potassium peroxydisulfate, and the catalyst played a dominant role. The introduction of Al2O3 promoted the formation of surface oxygen vacancies, which improved ligand complex formation between potassium peroxydisulfate and the catalyst, thereby facilitating electron migration. Furthermore, mesoporous silica spheres augment not only enhanced bisphenol A adsorption but also alleviated Cu leaching. Overall, this work is expected to provide significant support for the rational development of catalysts with high catalytic activity for persulfate activation via surface electron migration.

关键词： Cu–Al bimetallic oxides     mesoporous silica spheres     peroxydisulfate     bisphenol A    

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The modification of titanium in mesoporous silica for Co-based Fischer–Tropsch catalysts

《化学科学与工程前沿（英文）》 2022年 第16卷 第8期   页码 1224-1236 doi: 10.1007/s11705-022-2139-1

摘要： Ordered SBA-15 mesoporous silica with incorporated titanium was successfully synthesized via a one-pot hydrothermal crystallization method. The characterization including powder X-ray diffraction, Brunauer–Emmett–Teller, transmission electron microscope, temperature-programmed reduction, temperature-programmed desorption, Fourier transform infrared and ultraviolet-visible-near infrared spectrometer was performed to explore the physical and chemical structures of both the supports and the catalysts. The results showed that titanium was successfully incorporated into the mesoporous silica framework with a limited amount of titanium (Si/Ti > 20), and the mesoporous structure was retained. However, the increased titanium content inevitably resulted in the formation of anatase TiO 2 particles on the support surface. The increased incorporated titanium strengthened the interactions between cobalt species and supports, which was favorable for the cobalt species dispersion, despite the limited cobalt oxide reducibility. The enhanced metal-support interactions were beneficial for the CO/H2 ratio at the active cobalt sites, which facilitated the formation of more C5+ hydrocarbons. This study provides a promising method for support modification with incorporated-heteroatoms for the rational development of Fischer–Tropsch catalysts.

关键词： Fischer–Tropsch synthesis     titanium incorporation     mesoporous silica     metal-support interactions     C5+ selectivity    

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The construction of pseudo-Janus silica/surfactant assembly and their application to stabilize Pickering

《化学科学与工程前沿（英文）》 2022年 第16卷 第7期   页码 1101-1113 doi: 10.1007/s11705-021-2095-1

摘要： Nanoparticles with high surface energy and chemical activity have drawn substantial attention in petroleum industry. Recently, Janus nanoparticles exhibited tremendous potential in enhanced oil recovery (EOR) due to their asymmetric structures and properties. In this study, a series of amphiphilic pseudo-Janus@OTAB (PJ@C18) nanoparticles with different concentrations of stearyltrimethylammoium bromide (OTAB) were successfully fabricated. The structures and properties of PJ@C18 were characterized by Fourier transform infrared spectroscopy and ζ-potential measurements. Based on the emulsification experimental results, the interaction models and the self-assembly behavior between hydrophilic nanoparticles (SiO2@NH2) and OTAB molecules at the oil/water interface were proposed, which was further confirmed via the measurements of the contact angle and dynamic interfacial tension. Interestingly, it was found that the change of pH value from 7.5 to 4.0 caused the type reversal of the PJ@C18-1000 stabilized Pickering emulsions. Furthermore, the PJ@C18-1000 stabilized Pickering emulsion system with excellent salt and temperature tolerances (10000 mg∙L–1, 90 °C) significantly improved the oil recovery in the single-tube (more than 17%) and double-tube (more than 25%) sand pack model flooding tests. The findings of this study could help to better understand the construction mechanism of pseudo-Janus silica/surfactant assembly and the potential application of PJ@C18-1000 stabilized Pickering emulsions for EOR.

关键词： Janus nanoparticles     surfactant     double phase inversion     self-assembly     enhanced oil recovery    

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Effects of polyethylenimine on the dispersibility of hollow silica nanoparticles

WEN Lixiong, WANG Qing, ZHENG Tianyuan, CHEN Jianfeng

《化学科学与工程前沿（英文）》 2007年 第1卷 第3期   页码 277-282 doi: 10.1007/s11705-007-0050-4

摘要： In this study, two different methods were applied to disperse hollow silica nanoparticles (HSNP); one employed polyethylenimine (PEI) as the dispersant during the synthesis processes for preparing HSNP, while the other added PEI into suspensions of the prepared HSNP and used milling treatment to achieve the desired dispersion. It was found that adding PEI during the synthesis process of HSNP had no noticeable improvement in the dispersion, while adding PEI into suspensions of the prepared HSNP and utilizing milling treatment resulted in remarkable dispersion improvement. Therefore, the latter was chosen as the method in dispersing HSNP suspensions. The adsorption of PEI on the surface of HSNP and the stability of the aqueous suspensions was investigated. The results indicated that the adsorption of PEI on the surface of HSNP would increase the repulsive energy among particles, hence reducing the agglomeration of HSNP and improving the stability of the aqueous suspensions. The change of HSNP’s ζ potential after adding PEI and the relationship between the adsorbed amount of PEI and pH were also investigated.

关键词： dispersion improvement     different     prepared HSNP     relationship     agglomeration    

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Synthesis of MnFe

Jian LI,Yue JIAO,Caichao WAN

《农业科学与工程前沿（英文）》 2017年 第4卷 第1期   页码 116-120 doi: 10.15302/J-FASE-2017141

摘要： Cellulose aerogel, with abundant three-dimensional architecture, has been considered as a class of ideal eco-friendly matrix materials to encapsulate various nanoparticles for synthesis of miscellaneous functional materials. In the present paper, hexagonal single-crystalline MnFe O was fabricated and inserted into the cellulose aerogel using an chemical precipitation method. The as-prepared MnFe O nanoparticles were well dispersed and immobilized in the micro/nanoscale pore structure of the aerogel, and exhibited superparamagnetic behavior. In addition, the nanocomposite was easily actuated under the effect of an external magnetic field, revealing its strong magnetic responsiveness. Combined with the advantages of environmental benefits, facile synthesis method, strong magnetic responsiveness, and unique structural feature, this class of MnFe O /cellulose aerogel nanocomposite has possible uses for applications such as magnetically actuated adsorbents.

关键词： cellulose aerogel     MnFe2O4     magnetic responsiveness     nanocomposite    

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copolymerization of -isopropylacrylamide with 3-(methacryloxy)propyl trimethoxysilane on ultrafine silica

ZHANG Liping, ZHU Yi, NI Caihua

《化学科学与工程前沿（英文）》 2008年 第2卷 第3期   页码 242-247 doi: 10.1007/s11705-008-0043-y

摘要： Thermosensitive core-shell particles were synthesized through graft copolymerization of -isopropylacrylamide with [ 3-(methacryloxy) propyl]trimethoxysilane (MPT) coupled on the surface of ultrafine silica beads. The copolymerization was carried out using polyvinyl alcohol as a surfactant, water and cyclohexanol as mixed solvent, and 2,2′-azobis(isobutyronitrile) as an initiator. The effect of surfactant concentration and the composition of the mixed solvent on the graft rate were investigated. The structure of modified silica was confirmed by infrared spectra. Differential scanning calorimetry (DSC) has revealed the thermosensitivity of the particles. The thermosensitive particles were used as packing materials of high performance liquid chromatography (HPLC) columns for separating naphthalene derivatives. Satisfactory separation was obtained by controlling the temperature of the column. In contrast, the packing material of silica-MPT has no such separation efficiency due to the lack of thermosensitivity. The effect of the composition of the mobile phase on the separating efficiency was also investigated. The temperature-controlled separation was effective only when the water content was higher than 90% (v/v) in the water-methanol mobile phase. The mechanism for the temperature-controlled separation is attributed to a polarity change of poly(-isopropylacrylamide) which undergoes volume phase transition on the silica surface as the temperature increases.

关键词： undergoes     water-methanol     surfactant concentration     copolymerization     chromatography    

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Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

《化学科学与工程前沿（英文）》 2022年 第16卷 第8期   页码 1198-1210 doi: 10.1007/s11705-021-2133-z

摘要： Sulfonic acid functionalized mesoporous silica based solid acid catalysts with different morphology were designed and fabricated. The synthesized materials were characterized by various physicochemical and spectroscopic techniques like scanning electron microscope-energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface area, thermogravimetric analysis and n-butylamine acidity. The shape of catalysts particles plays an important role in its activity. The sulfonic acid functionalized mesoporous silica catalysts of spherical shape and the cube shape were assessed for catalytic activity in biodiesel production. The catalytic biodiesel production reaction over the catalysts were studied by esterification of free fatty acid, oleic acid with methanol. The effect of various reaction parameters such as catalyst concentration, acid/alcohol molar ratio, catalyst amount, reaction temperature and reaction time on catalytic activity were investigated to optimize the conditions for maximum conversion. It was sulfonated cubic shape mesoporous silica which exhibited better activity as compared to the spherical shape silica catalysts. Additionally, the catalyst was regenerated and reused up to three cycles without any significant loss in activity. The present catalysts exhibit superior performance in biodiesel production and it can be used for the several biodiesel feedstock’s that are rich in free fatty acids.

关键词： solid acid catalyst     mesoporous silica     sulfonic acid     biodiesel     esterification     oleic acid    

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Carbon-doped surface unsaturated sulfur enriched CoS@rGO aerogel pseudocapacitive anode and biomass-derived

《化学科学与工程前沿（英文）》 2021年 第15卷 第6期   页码 1500-1513 doi: 10.1007/s11705-021-2086-2

摘要： As a hybrid energy storage device of lithium-ion batteries and supercapacitors, lithium-ion capacitors have the potential to meet the demanding needs of energy storage equipment with both high power and energy density. In this work, to solve the obstacle to the application of lithium-ion capacitors, that is, the balancing problem of the electrodes kinetic and capacity, two electrodes are designed and adequately matched. For the anode, we introduced in situ carbon-doped and surface-enriched unsaturated sulfur into the graphene conductive network to prepare transition metal sulfides, which enhances the performance with a faster lithium-ion diffusion and dominant pseudocapacitive energy storage. Therefore, the lithium-ion capacitors anode material delivers a remarkable capacity of 810 mAh∙g–1 after 500 cycles at 1 A∙g–1. On the other hand, the biomass-derived porous carbon as the cathode also displays a superior capacity of 114.2 mAh∙g–1 at 0.1 A∙g–1. Benefitting from the appropriate balance of kinetic and capacity between two electrodes, the lithium-ion capacitors exhibits superior electrochemical performance. The assembled lithium-ion capacitors demonstrate a high energy density of 132.9 Wh∙kg–1 at the power density of 265 W∙kg–1, and 50.0 Wh∙kg–1 even at 26.5 kW∙kg–1. After 10000 cycles at 1 A∙g–1, lithium-ion capacitors still demonstrate the high energy density retention of 81.5%.

关键词： in-situ carbon-doped     surface unsaturated sulfur enriched     pseudocapacitive energy storage     biomass-derived carbon     lithium-ion capacitors    

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标题 作者 时间 类型 操作

A novel strategy for the construction of silk fibroin–SiO composite aerogel with enhanced mechanical

期刊论文

Effect of sodium bicarbonate solution on methyltrimethoxysilane-derived silica aerogels dried at ambient

Yujing Liu, Xiao Han, Balati Kuerbanjiang, Vlado K. Lazarov, Lidija Šiller

期刊论文

Fabrication of cellulose aerogel from wheat straw with strong absorptive capacity

Jian LI,Caichao WAN,Yun LU,Qingfeng SUN

期刊论文

Simple fabrication of carboxymethyl cellulose and κ-carrageenan composite aerogel with efficient performance

期刊论文

Hierarchically porous cellulose nanofibril aerogel decorated with polypyrrole and nickel-cobalt layered

期刊论文

Optimizing the compressive strength of concrete containing micro-silica, nano-silica, and polypropylene

Fatemeh ZAHIRI, Hamid ESKANDARI-NADDAF

期刊论文

Dispersion of “guava-like” silica/polyacrylate nanocomposite particles in polyacrylate matrix

QI Dongming, YANG Lei, WU Minghua, SHAO Jianzhong, BAO Yongzhong

期刊论文

Enhanced activation of persulfate using mesoporous silica spheres augmented Cu–Al bimetallic oxide particles

期刊论文

The modification of titanium in mesoporous silica for Co-based Fischer–Tropsch catalysts

期刊论文

The construction of pseudo-Janus silica/surfactant assembly and their application to stabilize Pickering

期刊论文

Effects of polyethylenimine on the dispersibility of hollow silica nanoparticles

WEN Lixiong, WANG Qing, ZHENG Tianyuan, CHEN Jianfeng

期刊论文

Synthesis of MnFe

Jian LI,Yue JIAO,Caichao WAN

期刊论文

copolymerization of -isopropylacrylamide with 3-(methacryloxy)propyl trimethoxysilane on ultrafine silica

ZHANG Liping, ZHU Yi, NI Caihua

期刊论文

Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

期刊论文

Carbon-doped surface unsaturated sulfur enriched CoS@rGO aerogel pseudocapacitive anode and biomass-derived

期刊论文