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The influence of silica on reaction rates and molecular hydrogen(H_(2))generation during olivine hydrothermal alteration

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Science China Earth Sciences 2024年第1期67卷 222-233页

作者： Ruifang HUANG Weidong SUN Xing DING Yusheng ZHAO Yibing LI Xiuqi SHANG CAS Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China SUSTech Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhen 518055China Center of Deep Sea Research Institute of OceanologyChinese Academy of SciencesQingdao 266071China State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Institue of Geology Chinese Academy of Geological SciencesBeijing 100037China

Hydrothermal alteration of olivine greatly influences geodynamics and the recycling of volatiles(such as water and carbon)in subduction zones.silica is an important component of geological fluids,and its influence on the hydrothermal alteration of olivine remains poorly constrained.In this study,we performed experiments at 300–515℃ and 3.0 kbar(1 bar=10^(5)Pa)by reacting well homogenized mixtures of olivine and silica powders with saline solutions(0.5 mol L^(−1)NaCl).silica greatly influences the reaction pathways,reaction rates,and molecular hydrogen(H_(2))formation during olivine hydrothermal alteration.In experiments at 300℃ and 3.0 kbar with mixtures of olivine and 10 wt%silica,olivine was replaced by serpentine and talc.The proportions of serpentine and talc were determined according to standard curves based on infrared spectroscopy analyses.Around 6.5%serpentine and 12%talc were produced after an experimental duration of 7 days,which had no change after a longer period(14 days).Compared to the kinetics in silica-free systems,the rates of olivine hydrothermal alteration in experiments with 10 wt%silica are much lower.The overall reaction is:4.5Forsterite+5.5SiO_(2),aq+4H_(2)O=Serpentine+2Talc.With the addition of more silica(20 wt%and 40 wt%),olivine was transformed into talc.The rates of reaction were much faster,e.g.,for experiments with olivine and 20 wt%silica,43%of talc was produced after 14 days,which increased to 77%for experiments with 40 wt%silica over the same period.The overall reaction is:3Forsterite+5SiO_(2),aq+2H_(2)O=2Talc.In experiments at 400–505℃ and 3.0 kbar,the promoting effect of silica on olivine hydrothermal alteration was also observed,which is closely associated with a decrease in Gibbs free energies of olivine hydrothermal alteration.At 300℃ and 3.0 kbar,silica decreased H_(2)formed during olivine hydrothermal alteration by around an order of magnitude,resulting in an increase in oxygen fugacity.Based on measured H_(2),we calibrated oxygen fugacities,ranging from 0.96 to 3.41 log un

关键词： Olivine hydrothermal alteration silica Serpentinization Hydrogen Serpentine

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3D Printed Polyimide/silica Composite Aerogels for Customizable Thermal Insulation from-50℃ to 1300℃

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Chinese Journal of Polymer Science 2024年第7期42卷 936-945,I0007页

作者： Dingyi Yu Tiantian Xue Zhuocheng Ma Zaiyin Hu Lijuan Long Yue-E Miao Wei Fan Tianxi Liu State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai201620China Key Laboratory of Synthetic and Biological Colloids Ministry of EducationSchool of Chemical and Material EngineeringJiangnan UniversityWuxi214122China Guizhou Aerospace Wujiang Electro-Mechanical Equipment Co. Ltd.Zunyi563000China School of Materials and Architectural Engineering Guizhou Normal UniversityGuiyang550025China

Aerogels are widely used as thermal insulation materials because of their high porosity and low bulk density.However,the insulation performance of aerogels is limited to a narrow temperature range.Besides,the preparation of aerogel materials with precisely controlled and complex architectures is still challenging.Here,we report 3D printed polyimide/silica aerogel particle(PI/SAP)composite aerogels for thermal insulation in a wide range of temperature with customized applications.The printability and shape fidelity of 3D printed composite aerogels is improved by adding hydrophilic SAP as a rheology modifier.The resulting PI/SAP composite aerogel exhibits excellent flame-retardant properties and thermal insulation from-50℃ to 1300℃.Moreover,the PI/SAP composite aerogel with customized shape can be applied for battery insulation at subzero temperatures,promising to be used as customizable and stable insulating materials in a variety of complex and extreme applications.

关键词： 3D printing Polyimide Aerogel silica Thermal insulation

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Janus mesoporous nanoparticles enable building biological logic systems

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Science China Chemistry 2024年第1期67卷 316-318页

作者： Haitao Li Jian Liu State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China College of Chemistry and Chemical Engineering Inner Mongolia UniversityHohhot 010021China

This highlight is inspired by a recent article in Nature Chemistry[1],in which Zhao and co-workers from Fudan University developed an innovative emulsion-orientated anisotropic assembly method for the controllable fabrication of MSN&mPDA(mesoporous silica nanoparticles=MSN,mesoporous polydopamine=mPDA)Janus mesoporous nanoparticles and used them to build biological logic systems.The reported Janus mesoporous nanoparticles have delicate structures and are well-controlled,and the authors also demonstrated the unique performance of this material at the application end.

关键词： enable emulsion silica

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Quantification of Silicon (SI) and Silicon Dioxide (SiO₂) from the Nafud Desert-Al-Qassim Region, Kingdom of Saudi Arabia Using XRD Analysis

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Advances in Materials Physics and Chemistry 2024年第5期14卷 67-75页

作者： Nagwa Ibrahim Mohamed Department of Physics College of Science Qassim University Buraydah Saudi Arabia

This research was conducted in the Qassim region, Kingdom of Saudi Arabia. The goal of this research is to determine the percentage of silicon in the Rub al-Khali desert. Samples were collected from four cities located in the Al-Qassim Region of Saudi Arabia (Uyun Al-Jawa, Al-Fuwailiq, Al-Sulaibiya, and Al-Qawara), from three distinct depths (the earth’s surface, 50 cm, and 100 cm). The percentages of silicon in these places vary between the highest value for silicon dioxide, which is 74.47 m/m%, and 34.8 m/m% for silicon in Al-Qawara city at a depth of 100 cm. We used an x-ray fluorescence (XRF) instrument to evaluate the samples. There are high percentage of both silica and silicon in the Nafud desert. Studies have shown that these ratios can help investors benefit from an element of Silicon and silicon dioxide, so the sands of the Nafud desert is sufficient for extracting Silicon and silica in huge quantities. This may transform the Kingdom into a leading country in the global computer technology industry that depends on silicon extracted from the desert sands, the most important of which are microcomputer data processing devices.

关键词： silica Sand Dispersive X-Ray Fluorescence (EDXRF) Analyzer Solar Cells Nafud Desert Al-Qawwarh

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Promotional effect of silica on the combustion of nano-sized aluminum powder in carbon dioxide

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Chinese Journal of Aeronautics 2022年第4期35卷 245-252页

作者： Baozhong ZHU Jinghui WANG Qichang WANG Yunlan SUN Weiqi CHEN Jiquan WANG School of Petroleum Engineering Changzhou UniversityChangzhou 213164China School of Energy and Environment Southeast UniversityNanjing 243002China

This paper presents how the combustion performance of nano-sized aluminum(nAl)powder in carbon dioxide are affected by silica. The ignition and combustion performance of nAl powder with silica addition were studied by a high-temperature tube furnace. An s-type thermocouple and a high-speed motion acquisition instrument were performed to evaluate the ignition temperature, maximum combustion temperature, maximum change of rate of temperature, and combustion propagation speed. The combustion efficiency and combustion products were measured and analyzed by a gas-volumetric method and an X-ray diffraction. The results show that silica added into nAl powder can enhance its maximum combustion temperature and maximum change of rate of temperature, while its ignition temperature increases slightly. The nAl powders with addition of 6.00 wt.% and 12.00 wt.% silica present high combustion propagation speeds, especially for the latter, it has high combustion efficiency. The effect mechanism of silica on the combustion of nAl powder in carbon dioxide was discussed.

关键词： Combustion Mechanism Nano-sized aluminum powder Promotional effect silica

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Emission of fused silica and KBr samples in the UV and visible spectral ranges under irradiation with 2.7 MeV electrons

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Matter and Radiation at Extremes 2022年第2期7卷 33-40页

作者： E.Kh.Baksht B.A.Alekseev A.G.Burachenko A.V.Vukolov A.P.Potylitsyn V.F.Tarasenko S.R.Uglov M.V.Shevelev Institute of High Current Electronics SB RAS 2/3 Akademichesky AvenueTomsk 634055Russia National Research Tomsk Polytechnic University Tomsk Polytechnic University30 Lenin AvenueTomsk 634050Russia

Fused silica and KBr samples were irradiated with a 2.7 MeV electron beam.The emission of fused silica and KBr samples in the UV and visible regions was studied under various experimental conditions.Numerical simulation of optical emission was carried out using the GEANT4 computer platform.Simulations of energy spectra and angular distributions of the beam electrons were performed for different target thicknesses.The results reveal the effect of scattering of the beam electrons on the angular distribution of Cherenkov radiation in fused silica samples with thicknesses exceeding the electron path length.

关键词： conditions. silica fused

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Preparation and evaluation of controllable drug delivery system:A light responsive nanosphere based on β-cyclodextrin/mesoporous silica

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Chinese Journal of Chemical Engineering 2023年第10期62卷 159-167页

作者： Yi Wu Hongzhou Shang Shisheng Lai Yali Di Xiaoran Sun Ning Qiao Lihua Han Zheng Zhao Yujin Lu College of Chemical Engineering North China University of Science and TechnologyTangshan 063210China College of Materials Science and Engineering North China University of Science and TechnologyTangshan 063210China College of Pharmacy North China University of Science and TechnologyTangshan 063210China Department of Cardiology Tangshan Central HospitalTangshan 063000China

A novel light responsive nanosphere was constructed,and it was used as a drug carrier to investigate the loading and release properties of the Quercetin(QU).In this paper,mesoporous silica nanoparticles(MSN)were used as a substrate,and 3-aminopropyl triethyoxysilane was used as a surface modification agent to introduce—NH_(2),and the azobenzene-4,4’-dicarboxylic acid(AZO)was used as light responsive agent to introduce the group of—N=N—,and thenβ-cyclodextrin(β-CD)was combined with AZO through host-guest interaction to construct light responsive nanoparticles(MSN@β-CD).The structure and properties of the carrier were analyzed by FTIR,BET,XPS,TGA,XRD,SEM and TEM.In vitro drug release studies showed the release rate of QU@MSN@β-CD(dark)was 12.19%within 72 h,but the release rate of QU@MSN@β-CD(light 10 min)was 26.09%,exhibiting a light-responsive property.The CCK8 tests demonstrated that MSN@β-CD could significantly decrease the toxicity of QU.Therefore,the controllable light-responsive drug delivery system has great application prospects.

关键词： silica Drug delivery system Light-responsive b-CD Nanomaterials Support

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An implantable antibacterial drug-carrier:Mesoporous silica coatings with size-tunable vertical mesochannels

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Nano Research 2022年第5期15卷 4243-4250页

作者： Mengli Liu Fang Huang Chin-Te Hung Liwei Wang Wei Bi Yupu Liu Wei Li Department of Chemistry Laboratory of Advanced MaterialsShanghai Key Lab of Molecular Catalysis and Innovative Materialsand State Key Laboratory of Molecular Engineering of PolymersFudan UniversityShanghai 200433China Zhongshan Hospital Fudan University(Xiamen Branch)Xiamen 361015China Department of Stomatology Zhongshan HospitalFudan UniversityShanghai 200032China

Implant-associated bacterial infection remains one of the most common and serious complications.Therefore,a surface boasting long-term antibacterial ability for implants is highly desirable.Herein,mesoporous silica coatings(MSCs)with vertical and size-tunable mesochannels are fabricated on a variety of metal substrates via a nano-interfacial oriented assembly approach.Such facile and versatile approach relies on the vertically oriented fusion of composite micelles on the nanoscale flatness surface of substrates.Such orientation assembly process endows the MSCs with vertical mesochannels,tunable mesopore size(ca.5.5-13.5 nm),and switchable substrates even with complex and diversified surfaces.Importantly,the MSCs on titanium substrates(Ti@MSCs)exhibit excellent performances for drug adsorption and sustained release.The saturation adsorption capacity can reach 0.544 μg·cm^(-2) towards minocycline hydrochloride(MC-HCl)antibiotic molecules,which is 6.5 times as the bare titanium(Ti)substrate.In addition,the drug release time can be controlled from 84 to 216 h by simply adjusting the mesopore size.As a proof of concept,the Ti@MSCs can realize a higher antibacterial rate(95.9%),compared with the bare Ti(70.3%).The results highlight the high potential of MSCs as implant coating for long-term preventing and eliminating peri-implantitis.

关键词： mesoporous coatings silica vertical mesochannels metal substrates drug carriers

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Establishment of nucleation and growth model of silica nanostructured particles and comparison with experimental data

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Chinese Journal of Chemical Engineering 2022年第10期50卷 379-388页

作者： Yubai Liu Zhiyuan Yu Thomas Pelster Ting-Tai Lee Yujun Wang Guangsheng Luo State Key Lab of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Evonik Operations GmbH Brühler Straße 2Wesseling 50389Germany Evonik Specialty Chemicals(Shanghai)Co. Ltd.Shanghai 201108China

A mathematical model is developed for the calculation of the nucleation and growth process of silica nanostructured particles prepared by using the drop-by-drop method,and the calculation results of the proposed model is compared with the experimental value obtained from SAXS data.The model provides a non-ideal improvement in the supersaturation calculation and considers the impact of both mass transfer and surface reaction on the particle growth rate.The nucleation and growth rates are coupled depending on the change in monomer concentration over time,based on which the particle size and distribution are calculated.The growth curve of the silica particles from 3 nm to 20 nm and the change in particle number from 0 to over 10^(20) are calculated,which are consistent with the experimental values,establishing the reliability of the model.The calculations of the growth rate reveal that mass transfer controls the growth of silica particles before 10 min and the surface reaction is the rate-determining step after 10 min.The changes in the model parameters obtained by fitting with the SAXS data under different reaction conditions indicate the sensitivity of the corresponding process to different conditions.Moreover,the relationship between the particle growth rate and monomer concentration change is analyzed using the proposed model.

关键词： silica Nucleation Growth Mathematical modeling Mass transfer Surface reaction

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Sticky-MARTINI as a reactive coarse-grained model for molecular dynamics simulations of silica polymerization

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npj Computational Materials 2022年第1期8卷 467-479页

作者： AndréP.Carvalho Sérgio M.Santos Germán Pérez-Sánchez JoséD.Gouveia JoséR.B.Gomes Miguel Jorge CICECO-Aveiro Institute of Materials Department of ChemistryUniversity of AveiroCampus Universitário de Santiago3810-193AveiroPortugal Department of Chemical and Process Engineering University of Strathclyde75 Montrose StreetGlasgowG11XJUK

We report a molecular modeling paradigm to describe silica polymerization reactions in aqueous solutions at conditions that are representative of realistic experimental processes like biosilicification or porous silica synthesis–i.***.at close to ambient temperatures and over a wide range of pH.The key point is to describe the Si-O-Si chemical bond formation and breakage processes through a continuous potential with a balance between attractive and repulsive interactions between suitably placed virtual sites and sticky particles.The simplicity of the model,its applicability in standard parallelized molecular dynamics codes,and its compatibility with the widely used MARTINI coarse-grained force-field allows for the study of systems containing millions of atoms over microsecond time scales.The model is calibrated to match experimental results for the temporal evolution of silica polymerization in aqueous solution close to the isoelectric point,and can describe silica polymerization and self-assembly processes during encapsulation of a surfactant micelle.

关键词： silica polymerization dynamics

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