Inorganic Porous Material Research Articles

Porous Ti3SiC2 fabricated by mixed elemental powders reactive synthesis

Abstract A novel porous material Ti3SiC2 is synthesized using reactive synthesis of mixed elemental powders. The synthesized porous Ti3SiC2 has high purity more than 99.0%. By adjusting the fabrication parameters, porous Ti3SiC2 can be synthesized with average pore diameters ranging from ∼200 nm to over ∼40 μm and open porosity ranging from ∼19.5% to ∼53.2%. The pore formation mechanism has been studied. Also, the synthesized porous Ti3SiC2 material presents promising mechanical properties. This novel porous material has the potential to replace the traditional inorganic porous material.

Preparation of hydroxyapatite-decorated poly(lactide-co-glycolide) microspheres for paclitaxel delivery

Paclitaxel (Tax) is an anticancer drug with extremely low water solubility, and development of the formulation without organic solvents is highly desirable. Hydroxyapatite (HA) is a biocompatible and porous inorganic material that can be used effectively in drug delivery systems, but poor dispersibility in water limits its application. In this study, HA-decorated poly(lactide-co-glycolide) (PLG) spheres with several micrometers were prepared and characterized. PLG microspheres adsorbed Tax, independent in the HA decorating, and their water dispersibility was retained after the HA decorating. Tax-loaded HA-decorated PLG microspheres (Tax/HA/PLG) could thus be highly dispersed in water, increasing their cellular uptake. Most Tax molecules were stably adsorbed to the HA and HA-decorated PLG (HA/PLG) particles. Although the cytotoxicity of Tax-loaded HA was much lower than that of free Tax, the drug activity of Tax/HA/PLG was markedly improved. Since the morphology of microtubules was changed after the Tax/HA/PLG treatment, the HA/PLG could work as a carrier for Tax.

Paclitaxel-loaded hydroxyapatite/collagen hybrid gels as drug delivery systems for metastatic cancer cells

Hydroxyapatite (HA) is a biocompatible and porous inorganic material that can behave as an effective drug carrier. In this study, HA nanoparticles were prepared according to the hydrothermal method and used as a drug carrier for a water-insoluble anticancer drug, paclitaxel (Tax). The absorption of Tax onto the HA was dependent on the solvent composition. The Tax-loaded HA (Tax/HA) exhibited a lower level of activity than the free Tax because the HA material was not stably dispersed in aqueous media. The Tax/HA was therefore embedded in a collagen gel to give the Tax/HA-embedded collagen gel (Tax/HA/Col), which exhibited a higher level of activity than the Tax-containing collagen gel (Tax/Col). Interestingly, the highly metastatic MDA-MB-231 cells were more sensitive to the Tax/HA/Col than the poorly metastatic MCF-7 cells. Tax/HA/Col is therefore useful for the drug delivery into metastatic cancer cells.

Porous silica supported Co2+-tetrachlorophthalocyanine (CoPcCl-APTES@SiO2): a novel and recyclable organic–inorganic hybrid catalyst for eco-friendly oxidation of secondary alcohols

A novel, selective and recyclable cobalt based catalyst has been synthesized by covalent grafting of Co2+-tetrachlorophthalocyanine (CoPcCl) onto porous silica functionalized with 3-aminopropyltriethoxysilane (APTES), and the resulting organic–inorganic hybrid porous material was found to be highly effective catalyst for peroxidative oxidation of secondary alcohols. The porous material was characterized by elemental analysis, diffuse reflectance UV–Visible spectroscopy, 13C CPMAS and 29Si CPMAS NMR spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), BET surface area analysis, Energy dispersive X-ray fluorescence (ED-XRF), Fourier transform Infrared (FT-IR) and Atomic absorption spectroscopy (AAS) techniques. High turnover frequency, mild reaction conditions, high selectivity for ketones, and easy recovery and reusability of the catalyst renders the present protocol highly essential to address the industrial needs and environmental concerns.

Controlled Drug Delivery From Composites of Nanostructured Porous Silicon and Poly( L -Lactide)

Porous silicon (pSi) and poly(L-lactide) (PLLA) both display good biocompatibility and tunable degradation behavior, suggesting that composites of both materials are suitable candidates as biomaterials for localized drug delivery into the human body. The combination of a pliable and soft polymeric material with a hard inorganic porous material of high drug loading capacity may engender improved control over degradation and drug release profiles and be beneficial for the preparation of advanced drug delivery devices and biodegradable implants or scaffolds. In this work, three different pSi and PLLA composite formats were prepared. The first format involved grafting PLLA from pSi films via surface-initiated ring-opening polymerization (pSi-PLLA [grafted]). The second format involved spin coating a PLLA solution onto oxidized pSi films (pSi-PLLA [spin-coated]) and the third format consisted of a melt-cast PLLA monolith containing dispersed pSi microparticles (pSi-PLLA [monoliths]). The surface characterization of these composites was performed via infrared spectroscopy, scanning electron microscopy, atomic force microscopy and water contact angle measurements. The composite materials were loaded with a model cytotoxic drug, camptothecin (CPT). Drug release from the composites was monitored via fluorimetry and the release profiles of CPT showed distinct characteristics for each of the composites studied. In some cases, controlled CPT release was observed for more than 5 days. The PLLA spin coat on pSi and the PLLA monolith containing pSi microparticles both released a CPT payload in accordance with the Higuchi and Ritger-Peppas release models. Composite materials were also brought into contact with human lens epithelial cells to determine the extent of cytotoxicity. We observed that all the CPT containing materials were highly efficient at releasing bioactive CPT, based on the cytotoxicity data.

Organic–inorganic hybrid porous sulfonated zinc phosphonate material: efficient catalyst for biodiesel synthesis at room temperature

A new porous zinc phosphonate material (HZnP-1) has been synthesized via the reaction between p-xylenediphosphonic acid and anhydrous ZnCl2 under hydrothermal and mildly acidic conditions (pH ∼ 5) in the absence of any structure directing agent. The phenyl group of this material has been sulfonated with concentrated sulfuric acid to obtain sulfonic acid functionalized material HZnPS-1. Powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE SEM), N2 sorption, solid state 13C CP MAS and 31P MAS NMR, and FT IR spectroscopic tools are employed to characterize these materials. The crystal structures of both the materials are indexed corresponding to the new orthorhombic phases with unit cell parameters a = 11.00, b = 8.74, c = 14.62 A, α = β = γ = 90° for HZnP-1, and a = 10.65, b = 13.52, c = 15.30 A and α = β = γ = 90° for HZnPS-1. HZnPS-1 showed outstanding catalytic activity and high recycling efficiency for the synthesis of different biodiesel compounds via esterification of long chain fatty acids by using methanol as both reactant and solvent at room temperature. The green and eco-friendly catalytic system described herein can overcome the problem faced by the existing catalytic systems known in biodiesel synthesis, such as drastic conditions (high reaction temperature) and requirement of hazardous organic solvents.

Development of the adsorbent for desiccant air-conditioning system by the inorganic porous material of clay family

Development of the adsorbent for desiccant air-conditioning system by the inorganic porous material of clay family

Optimizing Immobilization of Horseradish Peroxidase in the Nano-Scale Porous Structural Inorganic Material

Horseradish peroxidase was immobilized by montmorillonite to construct a nano-scale structural biocatalyst for the stabilization and/or detoxification of phenolic compounds from natural waters. Humic substances extracted from soils were used as a bonding agent, stimulating peptide covalent bonds between enzymes and surface of inorganic clay minerals. Operating conditions including concentrations of enzyme inoculated and duration time and temperature for the immobilization were examined and the optimal condition for maximizing the quantity of enzyme immobilized was found. The results of this study are expected to provide the essential information for the process-efficient and economic enzyme immobilization operations in the environmental engineering as well as for establishing ecological green U-City.

Superior CO2 Adsorption Capacity on N‐doped, High‐Surface‐Area, Microporous Carbons Templated from Zeolite

AbstractZeolite‐templated, high‐surface‐area, microporous, N‐doped carbons exhibit the highest CO2 uptake capacity recorded to date for any carbon material and one of the highest for any inorganic or organic porous material of up to 6.9 mmol g−1 at 273 K and ambient pressure and 4.4 mmol g−1 at ambient temperature and pressure, along with an initial CO2 adsorption energy of 36 kJ mol−1 at lower coverage and 20 kJ mol−1 at higher CO2 coverage. Combined with their ease of preparation, excellent recyclability and regeneration stability, and high selectivity for CO2, the N‐doped zeolite‐templated carbons are amongst the most promising solid‐state absorbents reported so far for CO2 capture and storage.

A New Binding Agent of Na<sub>2</sub>O-B<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> Syetem Sol for Expanded Perlite Thermal Insulation Board

In recent years, many buildings went up in flames one after another. It is thought-provoking. So the fire-proof property should be considered into one of the most important performance of the building thermal insulation materials. As a result, the study on the expanded perlite lightweight porous inorganic material heated up fast although its application still has some problems to be solved. In this paper, we take the expanded perlite as raw material to make thermal insulation board, and then study on the effect of volume weight on the coefficient of thermal conductivity and tensile strength. What is more important, we find that a new binding agent of Na2O-B2O3-SiO2 syetem sol contributes to improving its water resistance.

The Comparative Method for Apparent Density Measurement as a Means of Fine Carbonaceous and Inorganic Porous Material Characterization by the Determination of Shape Coefficient

These investigations are a part of work whose aim is an elaboration of a characterization method for porous fine powders with use of densimetric measurements. Especially, attention to methods of shape coefficient determination was given in this work because many other investigations pointed out that knowledge of this parameter is necessary for such studies. Shape coefficient values were determined with the use of Powers's method (K), the quantitative method (1/L), and the new comparative method (1/k). While densimetric measurements in the characterization of solids are a standard, the comparative method of apparent density determination is applied for the calculation of shape coefficients (1/k). The shape coefficient (1/k) characterizes not a single element of the fine solid but a collection of particles in the bed. The coefficient (1/k) represents the out-of-roundness degree of packed grains in relation to a bed of spheres with the same size distribution as the investigated material.

Celite-mediated linking of polyurethane block copolymers and the impact on the shape memory effect

Celite, a porous inorganic material with enormous surface area and hydroxyl groups on the surface, was used as a cross-linker of polyurethane (PU) copolymer chains to improve its shape memory and mechanical properties. PU copolymers with different Celite contents were prepared and characterized by IR, DSC, and universal testing machine. The glass transition temperature of PU copolymers was maintained around 20°C independent of Celite content. The shape memory and mechanical properties were dependent on when Celite was added during the polymerization reaction. The reaction in which Celite was added at the middle stage of polymerization showed the best shape memory and mechanical properties. The best shape recovery of PU was found at 0.3 wt % Celite and increased to 97% even after the third cycle. Likewise, the shape retention also maintained a remarkable 86% after three cycles. The reasons underlining the high shape recovery and shape retention by adopting Celite as a cross-linker are discussed in this article. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Catalytic Oxidative Cleavage of C=N Bond in the Presence of Zeolite H-NaX Supported , as a Green Reagent

Increasing awareness of environmental hazards forces chemists to look for “eco-friendly” reaction conditions. In this connection, the use of heterogeneous catalysts involving solid reagents supported on high surface area materials, obtained by introduction of the reagent onto or into an organic polymeric or an inorganic porous or layered support material meets the fundamental challenges in the protection of the environment. These supported reagents have advantages such as easy handling, good dispersion of active sites leading to improved reactivity, safer and milder reaction conditions and minimal pollution [1, 2]. Oximes, hydrazones, and semicarbazones are useful as preferred derivatives for the identification and characterization of carbonyl compounds [3]. Several reagents have been reported for the regeneration of the carbonyl groups from the mentioned derivatives [4– 9]. Although some of the methods involve mild reaction conditions, most of them require strong acidic media, long reaction time, a strong oxidizing agent (which causes over oxidation), and expensive and not readily available reagents. Anhydrous metallic nitrates with a bidentate covalent coordination and with the available lower intermediate oxidation state for the metal, find maximum reactivity, and wider applicability [10, 11]. Their use, however, in organic syntheses is limited by solubility problems. Laszlo et al. have used the K10-montmorillonite clay-supported copper(II) nitrate (claycop) and iron(III) nitrate (clayfen) for many of the organic reactions like oxidation of alcohols, oxidative coupling of thiols, hydrolytic cleavage of imine derivatives of carbonyl compounds, cleavage of tosylhydrazones, phenyl hydrazones, 2,4-dinitrophenylhydrazones and semicarbazones [12]. K10montmorillonite supported Thallium nitrate is used for the oxidative rearrangement of alkyl aryl ketones into alkyl aryl carboxylates [13]. Pyridinium chlorochromate [14], potassium dichromate [15] and sodium metaperiodate [16] are some alumina-supported oxidants used for the chemoselective oxidation of alcohols and sulfides. In this paper we report a general method for the oxidative cleavage of C=N to their carbonyl derivatives in excellent yields without using any microwave or ultrasonic irradiation. To the best of our knowledge, this is the first report using a zeolite-supported cupric nitrate as the reagent for the regeneration of carbonyl group from oximes, hydrazones and semicarbazones. Moreover, copper-salts are inexpensive, easy to handle and environmentally friendly.

Environmental corrosion resistance of porous TiAl intermetallic compounds

Porous TiAl intermetallic compound, as a novel substitute for current inorganic porous material, offsets the shortages of both ceramics and metals. The environmental corrosion resistance of porous TiAl intermetallic compound was investigated. The kinetic equation for the cyclic oxidation of porous TiAl alloy at 600 °C is determined to be Δ m 2=1.08×10 −5 t. After total oxidation of 140 h, porous TiAl intermetallic compound shows more stability of pore structure and the mass gain of TiAl alloy is 0.042 g/m 2, which is only 10.6% that of porous 316L stainless steel. The kinetic equation for the cyclic corrosion behavior of porous TiAl alloy in hydrochloric acid with pH=2 at 90 °C is determined to be Δ m 2=5.41×10 −5 t−2.08×10 −4. After 50 h exposure, the mass loss of TiAl alloy is 0.049 g/m 2, which is only 14.8% and 5.57% that of porous Ti and stainless steel, respectively. The kinetic equation in hydrochloric acid with pH=3 is determined to be Δ m 2=2.63×10 −6 t−3.72×10 −6.

Shape memory effects of polyurethane block copolymers cross-linked by celite

The shape memory polyurethane (PU) copolymers cross-linked by celite, a porous inorganic material with enormous surface area and hydroxyl groups on the surface, were prepared to see if the shape memory effect and the mechanical properties were improved. The PU copolymers with different celite contents were compared and characterized by IR, DSC, DMA, and UTM. The melting temperatures of PU soft segment were around 20 oC independent of celite content. The shape memory effect and mechanical properties were dependent on the celite content, and the celite addition into the reaction mixture should be made in the middle of polymerization to get the best shape memory and mechanical properties. The best mechanical properties were found at 0.2 wt% celite content and its shape retention rate went up to 98 %. The inclusion of celite as a cross-linker increased both shape memory effect and mechanical properties. The reasons underlining the improvements by adopting celite as a cross-linker are discussed in this paper.

Rapid antibiotic sensitivity testing and trimethoprim-mediated filamentation of clinical isolates of the Enterobacteriaceae assayed on a novel porous culture support

A porous inorganic material (Anopore) was employed as a microbial culture and microcolony imaging support. Rapid Anopore-based antibiotic sensitivity testing (AST) methods were developed to assess the growth of clinical isolates, with the primary focus on testing the response of the Enterobacteriaceae to trimethoprim, but with the method supporting a wider applicability in terms of strains and antibiotics. It was possible to detect the growth of Enterobacter aerogenes after 25 min culture and to distinguish a trimethoprim-sensitive from a trimethoprim-resistant strain with 40 min incubation. MIC(90) determinations were made on Anopore; these were in good agreement with the results from the Vitek 2 and E-test methods. The Anopore method correctly identified sensitive (40/40) and resistant (17/17) strains of the Enterobacteriaceae and other Gram-negative rods within only 2-3 h culture. Additionally, a trimethoprim-resistant subpopulation (10 % of population) could be detected by microcolony formation within 2 h, and a smaller subpopulation (1 %) after 3.5 h. These results suggest that this is a viable approach for the rapid AST of purified strains, and that it may be able to deal with mixed populations. The microscopic examination of microcolonies during AST is an advantage of this method which revealed additional information. Filamentation triggered by trimethoprim was discovered in many species of the Enterobacteriaceae for which this phenomenon has not previously been reported. Filamentation was characterized by heterogeneity in terms of cell length, and also uneven nucleic acid distribution and flattening of damaged cells. The development and application of Anopore-based AST within clinical diagnostics is discussed.

Highly Porous Silica Monoliths from Ethyl (L)-Lactate Modified Silanes

A new type of silica precursor was synthesized by (trans)alkoxylation of alkoxy- and chlorosilanes with ethyl (L)-lactate. This novel ethyl lactate modified silane was hydrolyzed and condensed in the presence of a non-ionic surfactant – poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) triblock copolymer (P123) – to give monolithic silica gels. The wet gels were dried using two different drying techniques resulting in crack-free monoliths: a) supercritical drying with CO2 to yield a porous inorganic material and b) surface silylation with trimethylchlorosilane to yield an inorganic–organic nanocomposite material. The obtained porous gels were characterized by different techniques including thermal analysis, nitrogen sorption, and electron microscopy (TEM, SEM).

Porous Alumina Silicate Matrix Gubka for Solidification of 137Cs Strip Product

AbstractSeparated liquid highâlevel radioactive waste (HLW) fractions, in particular, about 100 l of 137Cs strip product with activity up to ∼ 100 Ci/l (3.7 TBq/l) have been produced during the development and testing of partitioning technology and temporary stored at “V.G. Khlopin Radium Institute” (SaintâPetersburg, Russia). The benchâscale experimental unit designed for operation in the hot cell was developed for 137Cs strip product solidification with using of alumina silicate porous inorganic material (PIM) called Gubka.Conditions of saturation, drying and calcinations of the salts into Gubka pores were optimized and the operations under remote control regime were executed during tests with using of simulated strip product doped with 137Cs. The volume reduction coefficients were equal by a factor of 3.2â3.9 and 137Cs discharge into offâgas system was not detected. 137Cs leach rates from Gubka blocks after calcination at 800 °C were 1.0â1.5*10-3 g/m2*day.

Growth and Multiplexed Analysis of Microorganisms on a Subdivided, Highly Porous, Inorganic Chip Manufactured from Anopore

A highly porous inorganic material (Anopore) was shown to be an effective support for culturing and imaging a wide range of microorganisms. An inert barrier grid was printed on the rigid surface of Anopore to create a "living chip" of 336 miniaturized compartments (200/cm2) with broad applications in microbial culture.

A dynamic wicking technique for determining the effective pore radius of pregelatinized starch sheets

A dynamic wicking technique is employed for the first time for the determination of the effective mean pore radius of a thin-layer porous food: drum dried pregelatinized starch sheets. The technique consists of measuring the penetration rate of various n-alkanes in the porous matrix of the starch sheets and using this data to calculate the effective pore radius via the Washburn equation. Pore sizes in the order of a few nanometers have been determined in the starch sheets depending on the drum dryer’s operating variables (drum rotation speed, steam pressure and starch feed concentration). The conditions for the application of the technique in porous foods are discussed as compared to the conditions for single capillaries and inorganic porous material measured in other studies.