POROUS MEDIA

C E N T E R

Пористые и композиционные материалы

Строение,
характеристики,
свойства,
применение

Пористый кремний

Сайт содержит методические разработки и учебные материалы, связанные в первую очередь с изучением материаловедения, твёрдтельной электроники и оптики в рамках университетских курсов для направлений "техническая физика", "электроника и наноэлектроника", и родственных им специальностей. Акцент при этом сделан на приложении полученных знаний в область индустрии пористых материалов (сред), будь то фотоника, электроника, теплотехника, и пр. Приставка "нано-" в материалах сайта часто предваряет ключевые слова: "материал, композитный материал, фотоника, электроника, механика", характеризуя актуальную область научных интересов.

Сайт представляет собой экспериментальную разработку, нацеленную как на привлечение внимания студентов к очень интересному направлению в материаловедении, так и на возможность проводить постоянную коллективную работу по наполнению ресурса тематическими материалами и полезными ссылками. Авторы принимают критику и приветствуют пожелания и предложения сотрудничества.

  • Главная

Новости Nature

Graphene nanoplatelets as nanofillers in mesoporous silicon oxycarbide polymer derived ceramics

Cooperative adsorption of carbon disulfide in diamine-appended metal–organic frameworks

Metal-organic framework glasses with permanent accessible porosity

A robust zirconium amino acid metal-organic framework for proton conduction

Metal-induced ordered microporous polymers for fabricating large-area gas separation membranes

Author Correction: Natural gas upgrading using a fluorinated MOF with tuned H2S and CO2 adsorption selectivity

Continuous negative-to-positive tuning of thermal expansion achieved by controlled gas sorption in porous coordination frameworks

Ordered polymeric membranes using metals

Hierarchical Flowerlike 3D nanostructure of Co3O4@MnO2/N-doped Graphene oxide (NGO) hybrid composite for a high-performance supercapacitor

Porous hierarchy

Molecular sieving of ethylene from ethane using a rigid metal–organic framework

An efficient nanosieve

Лента новостей (Journal of Porous Materials)

High adsorption selectivity of zeolite X in the binary ionic system of Cu(II) and Zn(II)

Abstract

Competitive adsorption behavior of Cu(II) and Zn(II) from this binary system by X zeolite was systematically investigated. The kinetic data of Cu(II) and Zn(II) well fitted with pseudo-second order model. In the binary system, Cu(II) exhibits higher affinity and selectivity on X zeolite. Generally, the adsorption capacity of Zn(II) greatly decreased as the initial concentration of Cu(II) increased. On the contrary, the adsorption capacity of Cu(II) increased as the initial concentration of Zn(II) increased. The Langmuir isotherm model can best describe the adsorption isotherms of Cu(II). Furthermore, the competitive adsorption behavior of the X zeolite suggesting that it is endothermic and spontaneous. The physicochemical properties of presently tested X zeolite were characterized before and after adsorption, and the competitive adsorption mechanism was analyzed. It is indicated that the X zeolite synthesized from diatomite could be a promising candidate for separating certain heavy metals from industrial effluent.

Перейти к первоисточнику

Effect of high titanium blast furnace slag on preparing foam glass–ceramics for sound absorption

Abstract

Foam glass–ceramics for sound absorption were fabricated via a single-sintering method with high titanium blast furnace slag (HTBFS) and waste glass as the main materials. This study investigated the effects of HTBFS content on the microstructure and properties of foam glass–ceramics. The results show that the main phases of the sintered samples are diopside, perovskite and augite. With increasing HTBFS content from 38 to 48 wt%, the shape of crystals changes gradually and the crystallinity of the sintered samples decreases firstly and then increases, the bulk density and compressive strength increase, the porosity and open porosity decrease. All sintered samples have good sound absorption and corrosion resistant characteristics. The optimal properties, including the highest noise reduction coefficient (0.41) and a relatively high compressive strength (10.5 MPa) of the sintered samples, are prepared with 46 wt% HTBFS content. This research finds a new purpose of waste slag and expands the application range of foam glass–ceramics for sound absorption, especially sound barrier using in the traffic network because of a relative high impressive strength.

Перейти к первоисточнику

Study on the preparation of CdTe nanocrystals on the surface of mesoporous silica and evaluation as modifier of carbon paste electrodes

Abstract

Here CdTe nanocrystals were grown onto mesoporous silicas. The influence of the surface areas, volumes and pore diameters of the silica matrices on the spectroscopic properties of CdTe was evaluated. Emission properties of the CdTe were found to depend on the textural properties of silicas. Electrochemical characterization of different electrodes (unmodified carbon paste, and carbon paste modified with the mesoporous silica and with CdTe anchored onto mesoporous silica) evidenced that the presence of CdTe nanocrystals lead to a significant increase of the anodic peak referring to Cu2+ detection. The electrode with optimal characteristics responded to Cu2+ in the linear range from 5.0 × 10−8 to 2.3 × 10−6 mol L−1 and the calculated limit of detection was 6.4 × 10−8 mol L−1. The method developed here proved to be efficient for monitoring Cu2+ in sugar cane spirit (cachaça), with quantitative results comparable to those obtained from Flame Atomic Absorbtion Spectroscopy.

Перейти к первоисточнику

Huge enhancement in supercapacitive performance of oxygen-doped nano-carbon black

Abstract

In this paper, a nanometer-sized spherical carbon black (CB) with an average diameter of 30 nm was utilized to construct the compact carbon structure aiming at the electrode for high volumetric capacitance supercapacitors. The CB surface was modified by oxygen-doping to enhance the reaction with the electrolyte ions. BET result shows that oxygen-doping leads to the significant drop in both the SSA and the total pore volume of CB. Electrochemical measurement demonstrates that the oxygen-doped CB behaves an outstanding capacitive performance, its volumetric capacitance and gravimetric capacitance being up to 253 F cm−3 and 233 F g−1, almost 21.2 times improvement in comparison to those of the pristine CB (12 F cm−3 and 11 F g−1), respectively. Moreover, the oxygen-doped CB also exhibits an excellent cyclic stability, its capacitance remains 91.6% even after 10,000 cycles. Because of its advantages in mass production and low cost, the nano-sized carbon black can be considered as a competitive candidate for the mass production of the electrode materials for high volumetric performance supercapacitors.

Перейти к первоисточнику

Gas permeation properties of NaA zeolite membranes: effect of silica source on hydrogel synthesis and layer thickness

Abstract

NaA zeolite membranes were prepared on the inner surfaces of ceramic α-alumina tubes based on an aqueous phase synthesis in order to investigate the influence of different silica sources on NaA zeolite membrane synthesis and zeolite layer thickness with reference to the gas separation properties. SEM and XRD results indicated that zeolite prepared with sodium metasilicate as the silica source can be synthesized for a NaA zeolite membrane, leading to uniform zeolite layers and good thermal stability. The H2 permeance at 25 °C was 4.99 × 10−7 mol m−2 s−1 Pa−1, and the H2/Ar and H2/He permselectivities were 3.78 and 1.36, respectively. The morphologies and single gas permeation properties of the NaA zeolite membranes prepared through repeated aqueous phase synthesis treatments were also studied. When the zeolite layer thickness increased from 2.9 to 53 µm, the H2 permeance gradually decreased, while the permselectivities increased from 3.78 to 5.17. The gas permeance was mainly controlled by the Knudsen diffusion in our NaA zeolite membrane.

Перейти к первоисточнику

Fabrication of ordered mesoporous carbons with tunable pore architecture by the cosolvent

Abstract

Ordered mesoporous carbons (OMCs) with tunable mesophase were prepared by a novel cosolvent method using low molecular resin as carbon precursor, and P123(Poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide)triblock copolymers, EO20PO70EO20) as a template via an Evaporation-induced Self-assembly Process (EISA). The results show that the pore structure of OMCs could be oriented from 2D hexagonal (p6mm) to 2D centered rectangular (C2mm) structure. Two key descriptors of mesophase were identified. One is the ratio of PEO/PPO of triblock copolymer, and the other one is cosolvent, both of which would have effects on the interface of mesophase during the EISA process. Furthermore, it was confirmed that the ordered mesophase could be obtained in a very short time during the EISA process even accompanied by the microemulsion phenomenon.

Перейти к первоисточнику

TiO 2 -pillared magadiite and its arsenic adsorption capacity

Abstract

The structural and chemical interactions of magadiite with TiO2 pillars were examined along with arsenic adsorption potential of TiO2-pillared magadiite. The interlayer space of magadiite accommodated TiO2 in the form of moieties rather than discrete particles, which led to a slight increase in interlayer distance and consequently a remarkable formation of micropores (a specific surface area of 270 m2/g). High thermal stability up to 800 °C and increased interlayer space were attributed to the formation of Ti–O–Si bonding (966 cm−1) between interlayered silanol groups and TiO2 pillars. TiO2-pillared magadiite removed up to 100% of As(V) from aqueous solution at the initial concentrations of 0.5–1.0 mg L−1. These unique structural and textural evolutions of magadiite upon pillaring with TiO2 provide new insights to understand the pillaring behaviors of hydrated layered polysilicates and to fabricate pillared materials applicable to arsenate adsorption.

Перейти к первоисточнику

Rigid silica xerogel/alumina fiber composites and their thermal insulation properties

Abstract

Mechanically robust silica xerogel/alumina fiber composites were successfully prepared by a cost-effective ambient pressure drying route. Microstructure investigation shows that the alumina fibers embed into the silica xerogel matrix as reinforcements, which improves the strength of the composites greatly. As the alumina fibers volume increases to 4.0%, the compressive and flexural strength value of the composite is 0.96 MPa and 2.53 MPa, while the thermal conductivity at room temperature slightly changes between 0.051 and 0.059 W/mK. The composite is hydrophobic and keeps water repellent until 300 °C as shown by the TG–DSC result. After being heated at 800 °C for 25 min, the composite remains structurally intact demonstrated good thermal resistant property. The above characteristics indicate that the as prepared composite has great potential application as thermal insulation material in energy-saving area.

Перейти к первоисточнику