Sulfonic Acid Modified Hollow Silica Spheres and Its Application in Proton Exchange Membranes

In order to improve the proton conductivity of hollow silica spheres （HSS）/perfluorosulfonic acid ion-exchange （PFSA） composite membranes as proton exchange membrane,sulfonic acid groups were grafted onto the surfaces of HSS via post grafting methods.TEM images and FT-IR spectra of the obtained sulfonic acid groups modified hollow silica spheres （SAMHSS） illustrated that the sulfonic acid groups were successfully grafted onto the surfaces of HSS.Water uptake and swelling degree of SAMHSS/PFSA composite membranes were found much higher than those of HSS/PFSA membranes due to the introduction of hydrophilic sulfonic acid groups.In a range from 50 ℃ to 130 ℃,the highest conductivity of composite membranes was obtained when 5 wt% SAMHSS was loaded.The maximum conductivity reached 7.5×10-2 S·cm-1 at 100 ℃ and 100% relative humidity,even the temperature increased to 130 ℃,the conductivity of composite membranes with 5 wt% SAMHSS could reach 3.7×10-2 S·cm-1 at 100 % relative humidity,while the conductivity of the recast PFSA was only 2.2×10-3 S·cm-1.

Low-cost preferential different amine grafted silica spheres adsorbents for DAC CO_(2)removal

DAC CO_(2)capture is gaining wide attention as one of the most difficult carbon approaches to tackle climate change.In this work,different pore-size silica spheres were grafted using different amine groups such as APTES,APTMS,and Diamine.Herein,all samples based on the wet and dry grafting method were used for CO_(2)adsorption isotherm at room temperature and pressure(298 K and 1 bar).The sample based on the wet grafting(Silica-APTES-W)sample shows the highest CO_(2)uptake 1.67 mmol/g.Also,the adsorption isotherm of the Silica-APTES-W sample was showed a high capacity of CO_(2)1.2 mmol/g at 25℃,which describes the strong physical interaction between CO_(2)and amine.The isosteric adsorption of Silica-APTES-W also confirmed that the physical adsorption was dominant because of low adsorption heat ranging from 23 to 37 k J/mol.Also,the fixed bed experiment was conducted with 2000 ppm CO_(2)that obtains the optimal working capacity 4.5 m L/g with the lowest regeneration temperature 90℃.It was shown that Silica-APTES-W sample was superior performance for DAC CO_(2)capture in practical applications.

A Simple and “Green” Method for Synthesis of Magnetic Hollow Silica Spheres and Its ⁹⁹Tc^mLabeled Targeting Studies

The magnetic hollow silica spheres (MHSS) with uniform cavity size and shell thickness were prepared by a simple and “green” method using functionalized SiO2 spheres as templates. Magnetic particles (Fe3O4) were deposited on the SiO2 surface by varying the molar ratio of [Fe2+]/[Fe3+] and the molar concentration of iron salts. The obtained magnetic hollow silica spheres exhibited a super-paramagnetic behavior at room temperature. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray powder scattering (XRD) were applied to characterize the MHSS. Besides, their unit cell parameters are calculated according to results indexing to XRD, the MHSS sample prepared at 0.10 M iron salts and 2:1 molar ratio of [Fe2+]/[Fe3+] has a largest cell angle (β) of unit cell. Due to large hollow cavity space and super-paramagnetic characteristics, the inner amino-functionalized MHSS could be labeled with radioisotope 99Tcm to study the MHSS’s magnetic targeting distribution in vivo. These results indicate that the MHSS has potential in the magnetic targeted drug delivery system which reduces the damage to normal cells and improves the therapeutic effect of cancer.

Preparation and functionalization of mesoporous silica spheres as packing materials for HPLC

This paper presents the integrated results of a series of new methods for preparing mesoporous silica spheres as high-performance liquid chromatography （HPLC） packing materials. The separation performance of the mesoporous spheres materials has also been determined. Micrometer- sized silica spheres with uniform spherical morphologies and ordered mesostructures were first successfully synthesized by the method employing a water-soluble polymer-assisted assembly. Then the templates for getting ordered mesoporous materials with high-density silanol groups were removed by using hydrothermal oxidation. Finally the silica spheres were functionalized with C8 alkyl groups by surface modification under hydrothermal conditions. The resultant functionalized silica spheres were demonstrated to be excellent oacking materials for HPLC.

Fabrication linalool-functionalized hollow mesoporous silica spheres nanoparticles for efficiently enhance bactericidal activity

To develop a novel food preservation technology for efficiently enhance bactericidal activity in a long term,hollow mesoporous silica spheres(HMSS)with regular nanostructures were applied to encapsulate natural organic antimicrobial agents.The chemical structures,morphologies and thermal stabilities of linalool,HMSS and linalool-functionalized hollow mesoporous silica spheres(L-HMSS)nanoparticles were evaluated by polarimeter,field emission scanning electron microscope(FE-SEM),transmission electron microscope(TEM),fourier transform infrared(FT-IR),thermal gravimetric analyzer(TGA),nitrogen adsorption-desorption,zeta potential and small angle X-ray diffraction(SXRD).The results show that the linalool was successfully introduced into the cavities of HMSS,and the inorganic host exhibited a high loading capacity of about 1500 mg/g.In addition,after 48 h of incubatio n,the minimum bactericidal concentrations(MBC)of L-HMSS against Escherichia coli(E.coli),Salmonella enterica(S.enterica)and Staphylococcus aureus(S.aureus),Listeria monocytogenes(L.monocytogenes)were decreased to be 4(<5)mg/mL and 8(<10)mg/mL,respectively.These results revealed linaloolfunctionalized hollow mesoporous spheres could efficiently improve the bactericidal activities of the organic component.Furthermore,SEM images clearly showed that L-HMSS indeed had an extremely inhibitory effect against gram-negative(E.coli)and gram-positive(S.aureus)by breaking the structure of the cell membrane.This research is of great significance in the application of linalool in nano-delivery system as well as food industry.

Preparation of porous hollow silica spheres via a layer-by- layer process and the chromatographic performance

Hollow silica spheres possessing excellent mechanical properties were successfully prepared through a layer-by-layer process using uniform polystyrene （PS） latex fabricated by dispersion polymerization as template. The formation of hollow SiO2 micro-spheres, structures and properties were observed in detail by zeta potential, SEM, TEM, FTIR, TGA and nitrogen sorption porosimetry. The results indicated that the hollow spheres were uniform with particle diameter of 1.6 μm and shell thickness of 150 nm. The surface area was 511 m2/g and the pore diameter was 8.36 nm. A new stationary phase for HPLC was obtained by using C18-derivatized hollow SiO2 micro-spheres as packing materials and the chromatographic properties were evaluated for the separation of some regular small molecules. The packed column showed low column pressure, high values of efficiency （up to about 43 000 plates/m） and appropriate asymmetry factors.

Preparation of CdTe Nanocrystals Doped Fluorescent Silica Spheres by Sol-gel Method and Their Surface Modification via Thiol-ene Chemistry

A thcile one-step sol-gel method was used to prepare CdTe nanocrystals（NCs） doped silica microspheres with luxuriant thiol group on their surface using 3-mercaptopropyl trimethoxysilane（MPTMS） as organosilane in the aqueous solution. As the ligand and organosilane, MPTMS ensured the doping efficiency of CdTe NCs by ligand exchange and a large thiol group exposed to the solution to activate the surface of silica microspheres. The remodeled sol-gel process was performed at a lower temperature, which protected the thiol groups from degradation. Meanwhile, the particle size and size distribution can be controlled by varying synthesis conditions, such as the stirring rate and the reaction temperature. This user-friendly method provides a plattbrm tbr immobilization of chemical groups such as carboxyl for combination of bioactive and diagnostic molecules at the surface of CdTe NCs doped silica micro- spheres through thiol-ene chemistry for high-throughput microarrays.

Enhanced activation of persulfate using mesoporous silica spheres augmented Cu–Al bimetallic oxide particles for bisphenol A degradation

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■OH•,and■)and singlet oxygen(■)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.

Preparation of porous silica spheres with self-dispersing properties

A sol-gel procedure in a water/oil emulsion was introduced for the synthesis of porous silica spheres. Tetraethoxysilane was used as the silica source. The specific surface area and total pore volume of the product reached 772.3 m2/g and 0.663 cm3/g, respectively. The electrolyte washing process conferred a surface charge to the product, which displayed self-dispersal properties in water. The porous spheres have potential applications in the fields of drug delivery, controlled release capsules, indoor air pollutant scavengers, and hydrogen storage agents. The oil phase, which accounts for over 8O% of the chemical cost of the procedure, could largely be recycled by filtering, standing, and layering. The whole procedure is suitable for application as an industrial process.

Monodisperse hollow silica spheres： An in-depth scattering analysis

Herein, we fabricate hollow silica nanoparticles with exceptionally narrow size distributions that inherently possess two distinct length scales-tens of nanometers with regards to the shell thickness, and hundreds of nanometers in regards to the total diameter. We characterize these structures using dynamic and static light scattering （DLS and SLS）, small angle X-ray scattering （SAXS）, and transmission electron microscopy （TEM）, and we demonstrate quantitative agreement among all methods. The ratio between the radius of gyration （SLS） and hydrodynamic radius （DLS） in these particles equals almost unity, corresponding to ideal capsule behavior. We are able to resolve up to 20 diffraction orders of the hollow sphere form factor in SAXS, indicating a narrow size distribution. Data from light and X-ray scattering can be combined to a master curve covering a q-range of four orders of magnitude assessing all hierarchical length scales of the form factor. The measured SLS intensity profiles noticeably change when the scattering contrast between the interior and exterior is altered, whereas the SAXS intensity profiles do not show any significant change. Tight control of the aforementioned length scales in one simple and robust colloidal building block renders these particles suitable as future calibration standards.

Preparation of Silica–Alumina Hollow Spheres with a Single Surface Hole by Co-axial Microchannel

Si/Al composite hollow spheres with a surface hole were prepared with the co-axial microchannel in a one-step method. It is easy to use the technique for size control and continuous operation. At Si/Al ratio between 4 and 5, a hole forms on the surface, due to the fast gelation process and high viscosity of the sol. Scanning electron microscopy, nitrogen adsorption–desorption isotherms, and mercury intrusion method are used to characterize the samples. The hole size is 40–150 μm and the particle size is 450–600 μm. The size can be adjusted by the flow rate of the oil phase.

A vacuum nano-casting route to magnetite cores/mesoporous silica shell composites

Hollow mesoporous silica spheres with magnetite cores(HMSMC) have been fabricated by Vacuum Nano-casting Route. The amount of magnetite cores and saturation magnetization value can be easily adjusted by changing the concentration of iron nitrate solution used in the synthesis procedure. Furthermore, the as-prepared HMSMCs still maintain narrow mesopore distribution, high surface area and large pore volume after the hollow cores of hollow mesoporous silica spheres were filled with magnetite particles. Specially, when the saturation magnetization value of as-prepared HMSMCs reaches 22.0 emu/g, the surface area and pore volume of corresponding HMSMCs are 149 m^2/g and 0.19 cm^3/g, respectively, and the pore size is 2.30 nm. The corresponding samples are characterized by X-ray diffraction, N_2 sorption isotherms, transmission electron microscopy and vibrating-sample magnetometer.

Synthesis of Nanometer-sized Mesoporous Oxide Spheres

A few hundreds nanometer-sized mesoporous silica and alumina spheres were synthesized in organic solvents. The impacts of ammonia, N, N-dimethylformamide (DMF) and stirring speed were also investigated.

Multiple Energy Transfers in Rare Earth Complex-Doped SiO_2 Spheres

Silica spheres doped with Eu （TTFA）3 and/or Sm（TTFA）3 were synthesized by using the modified Stober method. The transmission electron microscope image reveals that the hybrid spheres have smooth surfaces and an average diameter of about 210 nm. Fluorescence spectrometer was used to analyze the fluorescence properties of hybrid spheres. The results show that multiple energy transfer processes are simultaneously achieved in the same samples co-doped with Eu （TTFA）3 and Sm（TTFA）3, namely between the ligand and Eu^3＋ ion, the ligand and Sm^3＋ ion, and Sm^3＋ ion and Eu^3＋ ion. Energy transfer of Sm^3＋→Eu^3＋ in the hybrid spheres leads to fluorescence enhancement of Eu^3＋ emission by approximately an order of magnitude. The lifetimes of the hybrid spheres were also measured.

Preparation of Carbon Nano-fiber Washcoat on Porous Silica Foam as Structured Catalyst Support

This paper reports how a hairy layer of carbon nano-fibers can be prepared on the macro-porous silica foam produced by the sphere templating method. Firstly, three-dimensional close-packed crystals of polystyrene spheres are assembled on porous disk substrate by vacuum filtration or evaporation. The polystyrene template is annealed slightly above the glass transition temperature in order to strengthen the colloidal crystal and ensure inter- connection of the spheres so as to obtain porous materials with open structure. Following the treatment of hexde- cyltrimethylammonium bromide, the polystyrene template is filled with silica colloidal solution, which solidifies in the cavities. Then the polystyrene particles are removed by calcination at 843K, leaving behind porous silica foam. Scanning electron microscopy images demonstrate that silica foam has uniform and open structured pores. Nickel particles were deposited on porous silica foam layer by the dipping method and porous carbon nano-fiber washcoat was prepared by catalytic decomposition of ethene over small nickel particles.

适用于深层产水气井的纳米粒子泡排剂

针对深层产水气井温度高、矿化度高、含高浓度H2S气体及凝析油的特点,研制了纳米粒子泡排剂,评价了其性能,并进行了现场试验。将耐高温的阴离子表面活性剂、耐高矿化度及H2S的两性离子表面活性剂及耐凝析油的氟碳表面活性剂进行复配制成液相泡排剂,再加入使用硅烷偶联剂改性的纳米二氧化硅球作为固态稳泡剂,制备出纳米粒子泡排剂。通过室内实验研究了泡排剂的性能,结果表明:泡排剂抗温可达150℃,抗矿化度可达250 g/L,抗H2S浓度可达0.04%,抗凝析油含量可达30%,起泡性、稳泡性优良。光学显微镜观察、Zeta电位表征结果说明,纳米粒子增强液相泡排剂性能的机理在于纳米粒子吸附在气液界面形成固态的粒子化膜,改性纳米二氧化硅球浓度约为0.002%时具有最佳稳泡效果。现场试验结果表明:泡排剂性能稳定,满足现场施工要求,可显著提高泡沫排水采气有效率并降低成本。

一种制备单分散SiO_2空心微球的新方法

在乙醇/氨水介质中,分别以分散聚合和无皂乳液聚合方法制得的不同粒径聚苯乙烯(PS)微球为模板,以正硅酸乙酯(TEOS)为前驱体,通过控制介质中氨水的初始体积,一步法制得了不同粒径的单分散SiO2空心微球.整个过程无需添加其它溶剂溶解或高温煅烧的方法来除去模板微球.对SiO2空心微球进行测试表征,提出了SiO空心微球的可能形成机制.

中空硅球表面分子印迹温敏聚合物吸附溶液中的四环素

本文开展了中空温敏分子印迹聚合物(HTMIPs)吸附溶液中四环素(TC)的实验研究,采用牺牲酵母模板法制备的中空硅球作为基质材料,以TC为模板分子,N-异丙基丙烯酰胺为温敏单体,通过沉淀聚合法合成了中空温敏型TC分子的印迹聚合物,利用FT-IR和SEM等方法对HTMIPs的理化性能进行表征,通过静态吸附实验考察HTMIPs对TC的吸附性能.结果表明,HTMIPs对模板分子TC在pH值为5.0时,35℃条件下吸附容量最大,约为72.05μmol·g^(-1),表明该印迹吸附剂对TC具有良好的亲和性和选择吸附性.HTMIPs的等温吸附结果与Freundlich模型拟合更好,动力学吸附结果更符合准二级动力学吸附模型,表明HTMIPs对于TC分子的吸附主要是在非均匀表面共价键作用下的结果.同时,HTMIPs表现出良好的可重复利用性,5次重复吸附-解吸附后吸附量损失约6.64%.因此,所制备的中空温敏印迹聚合物在吸附分离环境水体中的抗生素方面有良好的实际应用前景.

在SiO_2表面合成光滑纳米银壳的新方法——热裂解鄄熔流法

A new route for the preparation of silver nanoshells on silica spheres, leading to the establishment of a simple, efficient and easy-to-scale-up way for the synthesis of smooth silver nanoshells on silica monodispersed spheres, is reported through transforming the silver oxide shell to zero-valence silver by thermal cracking, applying surface strain theory to alter the shape of core-metal shell colloidal and form smooth metal nanoshell in hot inert flowing liquid. SEM images show that the silver nanoshells may be formed at 130 ℃ and deformed at 180 ℃ in hot inert flowing liquid. XRD indicates the formation of cubic structure pure silver with high crystallinity. Also, EDX and UV diffuse reflection spectrum analyses were conducted to characterize the as-prepared samples.