Nano-Silica Sol-Gel and Carbon Nanotube Coupling Effect on the Performance of Cement-Based Materials

AbstractNanocomposite silica thin films made using the sol-gel method were studied. The nano-silica films were prepared using a mixture of tetraethyl orthosilicate (TEOS), deionized water, ethanol, and ammonia solution. To control the growth of the particles inside the film, the nanocomposite silica film was prepared using a mixture of the nano-silica sol and the silica sol. The change in the particle size with the heat treatment temperature ranging from 450 °C to 1100 °C was investigated. X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), NKD (refractive index-N, extinction coefficient-K, and thickness-D) and ultraviolet-visible (UV-Vis) spectrophotometry were used for characterization purposes. The XRD studies showed that the nano-silica thin films were amorphous at all annealing temperatures except for 1100 °C. The_-cristobalite crystal structure formed at the annealing temperature of 1100 °C. Optical parameters, such as refractive indices and extinction coefficients, were obtained using the NKD analyzer with respect to the annealing temperature of the films. The activation energy and enthalpy of the nanocomposite silica film were evaluated as 22.3 kJ/mol and 14.7 kJ/mol, respectively. The cut-off wavelength values were calculated by means of extrapolation of the absorbance spectra estimated using the UV-Vis spectroscopy measurements. A red shift in the absorption threshold of the nanocomposite silica films indicated that the size of the silica nanoparticles increased with an increase of the annealing temperatures from 450 °C to 900 °C, and this confirms the quantum confinement effect in the nanoparticles.

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Effect and mechanism of colloidal silica sol on properties and microstructure of the hardened cement-based materials as compared to nano-silica powder with agglomerates in micron-scale

Cement and Concrete Composites ◽

10.1016/j.cemconcomp.2019.02.015 ◽

2019 ◽

Vol 98 ◽

pp. 137-149 ◽

Cited By ~ 5

Author(s):

Deyu Kong ◽

Haiwen Pan ◽

Linhai Wang ◽

David J. Corr ◽

Yang Yang ◽

...

Keyword(s):

Colloidal Silica ◽

Silica Sol ◽

Hardened Cement ◽

Nano Silica ◽

Silica Powder ◽

Cement Based Materials

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A carbon nanotube/silica sol–gel architecture for immobilization of horseradish peroxidase for electrochemical biosensor

Bioprocess and Biosystems Engineering ◽

10.1007/s00449-007-0126-z ◽

2007 ◽

Vol 30 (4) ◽

pp. 289-296 ◽

Cited By ~ 38

Author(s):

Jianwen Wang ◽

Ming Gu ◽

Junwei Di ◽

Yansheng Gao ◽

Ying Wu ◽

...

Keyword(s):

Carbon Nanotube ◽

Horseradish Peroxidase ◽

Electrochemical Biosensor ◽

Sol Gel ◽

Silica Sol

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Synergistically improved flame retardancy of the cotton fabric finished by silica-coupling agent-zinc borate hybrid sol

Journal of Industrial Textiles ◽

10.1177/15280837211028800 ◽

2021 ◽

pp. 152808372110288

Author(s):

Dan Li ◽

Zhen-hua Wang ◽

Yuan-shu Zhu ◽

Fei You ◽

Song-tao Zhou ◽

...

Keyword(s):

Cotton Fabric ◽

Flame Retardancy ◽

Coupling Agent ◽

Coupling Effect ◽

Synergistic Effects ◽

Sol Gel ◽

Cotton Fabrics ◽

Silica Sol ◽

Zinc Borate ◽

Limiting Oxygen Index

The sol-gel process has been applied to cotton fabrics to cover the fibers with a silica-based film, which can improve their thermal oxidation and combustion behaviors. Silica sol, silane coupling agent 3-glycidoxypropyltrimethoxysilane (KH560) and flame retardant zinc borate (ZB) are used together to prepare SiO2-KH560-ZB hybrid sol, which is then finished on the surface of cotton fabric through impregnation and baking. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), limiting oxygen index analysis (LOI) and microscale combustion calorimetry (MCC) are used to characterize functional groups, thermal stability and flammability properties of finished fabrics. Surface morphology of sol modified cotton fabrics are analyzed by scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDX). Results show the sols are successfully converted into gel coatings onto cotton fabrics, and continuous smoldering phenomenon of resulted fabrics disappears. ΔLOI/Δm of SiO2-KH560-ZB coated cotton fabric reaches the highest of 0.37%/g, char residue rate is as high as 28.43% and the peak heat release rate (PHRR) is reduced by 26.9% (83.7 W/g). KH560 has a significant coupling effect on combining components in the sol system and increases compatibility between sols and cotton fabrics. ZB (cooling, separation, dilution and suppression), silica sol (physical barrier) and KH560 show excellent synergistic effects in enhancing overall flame retardancy.

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A review on the properties, reinforcing effects, and commercialization of nanomaterials for cement-based materials

Nanotechnology Reviews ◽

10.1515/ntrev-2020-0023 ◽

2020 ◽

Vol 9 (1) ◽

pp. 303-322 ◽

Cited By ~ 3

Author(s):

Zhifang Zhao ◽

Tianqi Qi ◽

Wei Zhou ◽

David Hui ◽

Cong Xiao ◽

...

Keyword(s):

Cement Hydration ◽

State Of The Art ◽

Research Progress ◽

Market Survey ◽

Future Perspectives ◽

Nano Silica ◽

Physical Processes ◽

Existing Problems ◽

Cement Based Materials ◽

The Cost

AbstractThe behavior of cement-based materials is manipulated by chemical and physical processes at the nanolevel. Therefore, the application of nanomaterials in civil engineering to develop nano-modified cement-based materials is a promising research. In recent decades, a large number of researchers have tried to improve the properties of cement-based materials by employing various nanomaterials and to characterize the mechanism of nano-strengthening. In this study, the state of the art progress of nano-modified cement-based materials is systematically reviewed and summarized. First, this study reviews the basic properties and dispersion methods of nanomaterials commonly used in cement-based materials, including carbon nanotubes, carbon nanofibers, graphene, graphene oxide, nano-silica, nano-calcium carbonate, nano-calcium silicate hydrate, etc. Then the research progress on nano-engineered cementitious composites is reviewed from the view of accelerating cement hydration, reinforcing mechanical properties, and improving durability. In addition, the market and applications of nanomaterials for cement-based materials are briefly discussed, and the cost is creatively summarized through market survey. Finally, this study also summarizes the existing problems in current research and provides future perspectives accordingly.

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A simple approach to prepare fluorescent molecularly imprinted nanoparticles

RSC Advances ◽

10.1039/d0ra10618f ◽

2021 ◽

Vol 11 (13) ◽

pp. 7732-7737

Author(s):

Fenying Wang ◽

Dan Wang ◽

Tingting Wang ◽

Yu Jin ◽

Baoping Ling ◽

...

Keyword(s):

High Performance ◽

Low Cost ◽

Sol Gel ◽

Silica Sol ◽

Simple Approach ◽

Imprinted Polymer ◽

Molecularly Imprinted ◽

Low Toxicity ◽

Good Biocompatibility ◽

Molecularly Imprinted Nanoparticles

Fluorescent molecularly imprinted polymer (FMIP) gains great attention in many fields due to their low cost, good biocompatibility and low toxicity. Here, a high-performance FMIP was prepared based on the autocatalytic silica sol–gel reaction.

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The role of embedded 2-ABT@Cu-BTC MOF on the anti-corrosion performance of electro-assisted deposited silica sol-gel composite film

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2021.124590 ◽

2021 ◽

Vol 267 ◽

pp. 124590

Author(s):

Zahra Mohammadpour ◽

Hamid R. Zare

Keyword(s):

Composite Film ◽

Sol Gel ◽

Silica Sol ◽

Corrosion Performance

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Effects of nano silica on the properties of cement-based materials: A comprehensive review

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.122715 ◽

2021 ◽

Vol 282 ◽

pp. 122715 ◽

Cited By ~ 1

Author(s):

Haibin Yang ◽

Manuel Monasterio ◽

Dapeng Zheng ◽

Hongzhi Cui ◽

Waiching Tang ◽

...

Keyword(s):

Nano Silica ◽

Comprehensive Review ◽

Cement Based Materials

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Silica Sol-Gel Supported Nickel Nano-Catalyst for Hydrogen Production Using Microreactors

MRS Proceedings ◽

10.1557/proc-0885-a10-09 ◽

2005 ◽

Vol 885 ◽

Author(s):

Krithi Shetty ◽

Shihuai Zhao ◽

Wei Cao ◽

Naidu V. Seetala ◽

Debasish Kuila

Keyword(s):

Steam Reforming ◽

Average Pore Size ◽

Sol Gel ◽

Supported Catalyst ◽

Silica Sol ◽

Average Pore ◽

Steam Reforming Of Methanol ◽

Nano Catalyst ◽

Before And After ◽

Reforming Reactions

ABSTRACTThe goal of this research is to investigate the activities of a non-noble nano-catalyst (Ni/SiO2) using Si-microreactors for steam reforming of methanol to produce hydrogen for fuel cells. The supported catalyst was synthesized by sol-gel method using Ni (II) salts and Si(C2H5O)4 as starting materials. EDX results indicate that the actual loading of Ni (5-6%) is lower than the intended loading of 12 %. The specific surface area of the silica sol-gel encapsulated Ni nano-catalyst is 452 m2/g with an average pore size of ∼ 3 nm. Steam reforming reactions have been carried out in a microreactor with 50 µm channels in the temperature range of 180-240 °C and atmospheric pressure. Results show 53% conversion of methanol with a selectivity of 74 % to hydrogen at 5 l/min and 200 °C. The magnetic properties of the catalysts were performed using a Vibrating Sample Magnetometer (VSM) to study the activity of the catalysts before and after the steam reforming reactions. The VSM results indicate much higher activity in the microreactor compared to macro-reactor and Ni forms non-ferromagnetic species faster in the microreactor.

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