Name: facile preparation of ultrafine aluminum hydroxide particles with or without mesoporous mcm-41 in ambient environments
Uploaded: 2017-05-11T15:00:00.000+00:00
Duration: 5 min 50 s
Description: Watch this Scientific Journal Video about Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments at JoVE.com

Die Autoren erweitern ihre Anerkennung für Dr. Thomas J. Emge und Wei Liu von Rutgers University für ihre Analyse und Expertise in Kleinwinkel-Röntgenbeugung und Pulver Röntgenbeugung. Darüber hinaus erkennen die Autoren Hao Wang für seine Unterstützung mit den N 2 Adsorptionsexperimenten an.

1. Al (OH) 3 Nanopartikel-Synthese <ol><li> 1.40 g Aluminiumchloridhexahydrat in 5.822 g entionisiertem Wasser auflösen </li><li> 2.778 g L-Arginin zu der wässrigen Aluminiumchloridlösung unter magnetischem Rühren zugeben. Füge das L-Arginin langsam hinzu, so dass sich das hinzugefügte Arginin auflöst und keine großen Klumpen oder Klumpen bildet; Darüber hinaus reduziert eine langsame Zugabe lokale Konzentrationen der Alkalinität und liefert Bedingungen für eine kontrollierbarere Hydrolyse. </li><li> Sobald sich das Arginin in die Lösung auflöst, erhitze man die Lösung für 72 h bei 50 ° C; An dieser Stelle kann die Lösung als trübe Suspension erscheinen. </li></ol> 2. Präzipitieren von Al (OH) 3 mit NaCl <ol><li> Bereiten Sie eine GPC-Säule vor, die 49 in einem langen und 1.125 im Durchmesser ist. Packen Sie das Gel in aufeinanderfolgenden Schritten des Hinzufügens von Gel und lassen Sie Wasser durch die Säule fließen, um eine korrekte Verpackung zu gewährleisten, mit einem minimalen Raum zwischen den Gelperlen. Pack dieGel bis etwa 80% der Säule; Die Menge an gepacktem Gel variiert jedes Mal und wirkt sich nur auf die Retentionszeit der abgetrennten Spezies aus. </li><li> Führen Sie 10 mL as-synthetisierte Al (OH) 3 Nanopartikel-Suspension (hergestellt in Schritt 1.3) in die Säule unter Verwendung einer HPLC-Pumpe mit einer 10 mL Injektorschleife ein. Die Injektorschleife mit einem Außendurchmesser von ca. 0,125 Zoll und einer Länge, die kalibriert ist, um 10 ml injizierte Probe zu liefern, </li><li> Sammeln Sie die Säulenelution in Intervallen, die mit der dRI-Peak-Position korrelieren. Verbinden Sie den GPC-Ausgang mit dem Eingang eines Differential-Brechungsindex (dRI) -Detektors. HINWEIS: Da getrennte Spezies aus der GPC kommen, erscheinen sie auf dem dRI-Detektor als Peak und werden dann in 125 ml Flaschen gesammelt. Die GPC-Säule produziert zwei gut aufgelöste Peaks, die beide gesammelt und mit Größenausschlusschromatographie (SEC) und Elementaranalyse (EA) analysiert werden, um Arginin aus Aluminium spe zu erkennenCies Das gesammelte Gesamtvolumen hängt von der Größe der GPC-Säule, der Gesamtmenge des verwendeten Verpackungsmaterials und der Strömungsgeschwindigkeit des entionisierten Wassers ab, das verwendet wird, um die Säule zu eluieren. <ol><li> Sammeln Sie die Mehrheit der Peak-1-Fraktion über 100 min bei einer 0,2 ml / min Fließgeschwindigkeit. </li><li> Sammeln Sie das Elutionsmittel in 30-Minuten-Intervallen, sobald ein Peak auf dem RI-Detektor der GPC-Säule austritt. HINWEIS: Das Ändern des Intervallbereichs ändert die Konzentration und Reinheit des resultierenden gereinigten Peak 1-Materials. Es empfiehlt sich, zunächst kleine Intervalle des Peaks zu sammeln, um zu bestimmen, welcher Teil die höchste Konzentration und Reinheit der Peak-1-Spezies für eine bestimmte Säule enthält. </li></ol></li><li> 1 Gew .-% NaCl zubereiten. </li><li> Man gibt die hergestellte NaCl-Lösung tropfenweise zu 10 ml gereinigter Al (OH) 3 -Nanopartikel; Das unter Verwendung von NaCl-Präzipitation hergestellte Material wird für weitere Experimente nicht verwendet. </li></ol> 3. Vorbereitung von Al-MCM-41 <ol><li> AcTeste ca. 1,0 g MCM-41 bei 120 ° C unter Vakuum für 3 h in einem Vakuumofen. </li><li> 50,0 g Aluminiumchloridlösung durch Kombination von 9,6926 g AlCl &amp; sub3; · 6H &amp; sub2; O mit 40,3074 g entionisiertem Wasser zubereiten. </li><li> Füge 0,7 g aktiviertes MCM-41 zu 50,0 g Aluminiumchloridlösung (hergestellt in Schritt 3.2) zu. </li><li> Erlaube eine ausreichende Mischzeit (1 Std.), Um die Homogenität des AlCl 3 zu gewährleisten, die über die MCM-41 Kanäle diffundiert ist. </li><li> Füge L-Arginin zu der heterogenen Mischung zu einem Arg / Al-Molverhältnis von 2,75 unter magnetischem Rühren hinzu. Ähnlich wie bei Schritt 1.2 fügen Sie das Arginin langsam so hinzu, dass die sofort gebildeten Flockungsmittel wieder auflösen und das Verklumpen des Arginins reduzieren können, bevor die Zugabe fortgesetzt wird. </li><li> Nach der Homogenität die Mischung bei 50 ° C für 72 h erhitzen. </li><li> Filtriere die erhaltene heterogene Lösung unter Verwendung eines Buchner-Trichters unter Vakuum und wurde mit qualitativen 90-mm-Filterpapierkreisen ausgestattet(Oder andere geeignete Filterpapiere). </li><li> Waschen Sie das gefilterte weiße Pulver mit überschüssigem deionisiertem Wasser, um die Entfernung von nicht umgesetztem Aluminiumchlorid, Arginin oder wasserlöslichen Nebenprodukten aus dem hergestellten Al-MCM-41-Material zu gewährleisten. </li></ol>

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Die Autoren haben nichts zu offenbaren.

Die Herstellung einer wässrigen Aluminiumchloridlösung ergab die Verwendung eines kristallinen Hexahydratsalzes von Aluminiumchlorid. Obwohl die wasserfreie Form auch verwendet werden kann, ist es aufgrund ihrer signifikanten hygroskopischen Eigenschaften nicht bevorzugt, was es schwierig macht, mit der Konzentration von Aluminium zu arbeiten und diese zu kontrollieren. Es ist bemerkenswert, dass Aluminiumchloridlösung innerhalb von einigen Tagen nach der Herstellung verwendet werden sollte, da im Laufe der Zeit die ...

Materialien aus Aluminiumhydroxid sind vielversprechende Kandidaten für eine Vielzahl von industriellen Anwendungen, einschließlich Katalyse, Pharma, Wasseraufbereitung und Kosmetik. 1 , 2 , 3 , 4 Bei erhöhten Temperaturen absorbiert Aluminiumhydroxid eine wesentliche Menge an Wärme während der Zersetzung, um Aluminiumoxid (Al &amp; sub2; O &amp; sub3; ) zu ergeben, was es zu einem nützlichen flammhemmenden Mittel macht. 5 Die vier bekannten Polymorphe von Aluminiumhydroxid ( dh Gibbsit, Bayerit, Nordstrandit und Doyleit) wurden unter Verwendung von rechnerischen und experimentellen Techniken untersucht, um unser Verständnis der Entstehung und Strukturen zu verbessern 6 . Die Herstellung von nanoskaligen Partikeln ist aufgrund ihres Potentials, Quanteneffekte und Eigenschaften zu zeigen, die sich von denen der Thei unterscheiden, von besonderem InteresseR Bulk-Pendants. Nanogibbsit-Partikel mit Abmessungen in der Größenordnung von 100 nm werden unter verschiedenen Bedingungen 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 leicht hergestellt. Die Überwindung von inhärenten Herausforderungen, die mit der Verringerung der Partikelgrößen verbunden sind, ist schwierig; Daher gibt es nur wenige Fälle, wo Nanogibbsit-Partikel Dimensionen in der Größenordnung von 50 nm haben. 14 , 15 , 16 , 17 Nach unserem besten Wissen gab es keine Berichte über Nanogibbsit-Partikel kleiner als 50 nm. Dies ist zum Teil darauf zurückzuführen, dass Nanopartikel aufgrund elektrostatischer Instabilität dazu neigen, zu agglomerierenUnd die hohe Wahrscheinlichkeit für die Bildung von Wasserstoffbrücken zwischen den kolloidalen Partikeln, insbesondere in polaren protischen Lösungsmitteln. Unser Ziel war es, kleine Al (OH) 3 Nanopartikel unter Verwendung von ausschließlich sicheren Zutaten und Vorläufern zu synthetisieren. In der gegenwärtigen Arbeit wurde die wässrige Teilchenaggregation durch Einbringen einer Aminosäure ( dh L-Arginin) als Puffer und Stabilisator gehemmt. Darüber hinaus wird berichtet, dass das Guanidinium-haltige Arginin das Wachstum von Aluminiumhydroxid und die Aggregation verhinderte, um eine wässrige kolloidale Suspension mit durchschnittlichen Teilchengrößen von 10-30 nm zu ergeben. Es wird hier vorgeschlagen, dass die amphoteren und zwitterionischen Eigenschaften von Arginin die Oberflächenladung von Aluminiumhydroxid-Nanopartikeln während der milden Hydrolyse verminderten, um das Partikelwachstum über 30 nm zu verhindern. Obwohl Arginin nicht in der Lage war, die Teilchengröße unter 10 nm zu reduzieren, wurden solche Teilchen erreicht, indem der Vorteil des &quot;Käfig&quot; -Entwicklungseffekts ausgenutzt wurdeHin die mesoporen von MCM-41. Die Charakterisierung des Al-MCM-41-Verbundwerkstoffs ergab ultrafeine Aluminiumhydroxid-Nanopartikel innerhalb des mesoporösen Siliciumdioxids, das eine mittlere Porengröße von 2,7 nm aufweist.

<table><tbody><tr><td>aluminum chloride hexahydrate</td><td>Alfa Aesar</td><td>12297</td><td></td></tr><tr><td>L-arginine</td><td>BioKyowa</td><td>N/A</td><td></td></tr><tr><td>aluminum hydroxide</td><td>Sigma Aldrich</td><td>239186</td><td></td></tr><tr><td>Bio-Gel P-4 Gel</td><td>Bio-Rad</td><td>150-4128</td><td></td></tr><tr><td>Mesoporous siica (MCM-41 type)</td><td>Sigma Aldrich</td><td>643645</td><td></td></tr></tbody></table>

facile preparation of ultrafine aluminum hydroxide particles with or without mesoporous mcm-41 in ambient environments

Eine wässrige Suspension von Nanogibbsit wurde über die Titration von Aluminium-Aqua-Säure [Al (H 2 O) 6 ] 3+ mit L-Arginin auf pH 4,6 synthetisiert. Da die Hydrolyse von wässrigen Aluminiumsalzen bekannt ist, eine breite Palette von Produkten mit einer breiten Palette von Größenverteilungen herzustellen, wurde eine Vielzahl von hochmodernen Instrumenten ( dh 27 Al / 1 H NMR, FTIR, ICP-OES) , TEM-EDX, XPS, XRD und BET) wurden zur Charakterisierung der Syntheseprodukte und zur Identifizierung von Nebenprodukten verwendet. Das Produkt, das aus Nanopartikeln (10-30 nm) bestand, wurde mittels Gelpermeationschromatographie (GPC) Säulentechnik isoliert. Fourier Transformation Infrarot (FTIR) Spektroskopie und Pulver Röntgenbeugung (PXRD) identifiziert das gereinigte Material als Gibbsit Polymorph von Aluminiumhydroxid. Die Zugabe von anorganischen Salzen ( zB NaCl) induzierte eine elektrostatische Destabilisierung der Suspension, wodurch die Nanopartikel zu yie agglomeriert wurdenLd Al (OH) 3 mit großen Teilchengrößen ausfallen. Unter Verwendung des hier beschriebenen neuartigen Syntheseverfahrens wurde Al (OH) 3 teilweise in das hochgeordnete mesoporöse Gerüst von MCM-41 mit mittleren Porenabmessungen von 2,7 nm geladen, wodurch ein Aluminosilikatmaterial mit sowohl oktaedrischem als auch tetraedrischem Al (O h / T d = 1,4). Der Gesamt-Al-Gehalt, gemessen unter Verwendung der energiedispersiven Röntgenspektrometrie (EDX), betrug 11% G / G mit einem Si / Al-Molverhältnis von 2,9. Ein Vergleich von Massen-EDX mit Oberflächen-Röntgen-Photoelektronenspektroskopie (XPS) Elementaranalyse lieferte Einblick in die Verteilung von Al innerhalb des Aluminosilikatmaterials. Weiterhin wurde ein höheres Verhältnis von Si / Al auf der äußeren Oberfläche (3.6) im Vergleich zur Masse (2.9) beobachtet. Approximationen von O / Al-Verhältnissen deuten auf eine höhere Konzentration von Al (O) 3 und Al (O) 4- Gruppen nahe dem Kern bzw. der äußeren Oberfläche hin. Die neu entwickelte Synthese von Al-MCM-41 ergibt eine Re-Licht hoher Al-Gehalt unter Beibehaltung der Integrität des geordneten Siliciumdioxidgerüsts und kann für Anwendungen verwendet werden, bei denen hydratisierte oder wasserfreie Al 2 O 3 -Nanopartikel vorteilhaft sind.

Nanogibbsit-Synthese Nanogibbsit wurde durch Titration von AlCl &amp; sub3; · 6H &amp; sub2; O (14 Gew .-%) mit L-Arginin zu einem endgültigen Arg / Al-Molverhältnis von 2,75 hergestellt. Die Synthese von Nanogibbsit-Partikeln wurde über SEC überwacht , was eine weit verbreitete Analysetechnik für partiell hydrolysierte Aluminiumchloridlösungen ist, die in der Lage ist, fünf Domäne...

Watch this Scientific Journal Video about Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments at JoVE.com

Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

Eine ultrafeine Aluminiumhydroxid-Nanopartikel-Suspension wurde über die kontrollierte Titration von [Al (H 2 O)] 3+ mit L-Arginin auf pH 4,6 mit und ohne Käfigeffekt-Confinement in mesoporösen Kanälen von MCM-41 hergestellt.

Facile Vorbereitung von ultrafeinen Aluminiumhydroxidpartikeln mit oder ohne mesoporösem MCM-41 in Umgebungsbedingungen

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis ...

facile-preparation-ultrafine-aluminum-hydroxide-particles-with-or

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

10.8K Aufrufe.  Colgate-Palmolive Company.  Eine ultrafeine Aluminiumhydroxid-Nanopartikel-Suspension wurde über die kontrollierte Titration von [Al (H 2 O)] 3+ mit L-Arginin auf pH 4,6 mit und ohne Käfigeffekt-Confinement in mesoporösen Kanälen von MCM-41 hergestellt. 

Serie: Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

Preparation of Silica Nanoparticles Through Microwave-assisted Acid-catalysis

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle diameters ranging from 30-250 nm by varying the reaction conditions. Through the selection of a microwave compatible solvent, silicic acid precursor, catalyst, and microwave irradiation time, these microwave-assisted methods were capable of overcoming the previously reported shortcomings associated with synthesis of silica nanoparticles using microwave reactors. The siloxane precursor was hydrolyzed using the acid catalyst, HCl. Acetone, a low-tan &#948; solvent, mediates the condensation reactions and has minimal interaction with the electromagnetic field. Condensation reactions begin when the silicic acid precursor couples with the microwave radiation, leading to silica nanoparticle sol formation. The silica nanoparticles were characterized by dynamic light scattering data and scanning electron microscopy, which show the materials&#39; morphology and size to be dependent on the reaction conditions. Microwave-assisted reactions produce silica nanoparticles with roughened textured surfaces that are atypical for silica sols produced by St&#246;ber&#39;s methods, which have smooth surfaces.

Silica nanoparticles were prepared using acid-catalysis of a siloxane precursor and microwave-assisted synthetic techniques resulting in the controlled growth of nanomaterials ranging from 30-250 nm in diameter. The growth dynamics can be controlled by varying the initial silicic acid concentration, time of the reaction, and temperature of reaction.

Herstellung von Silica-Nanopartikeln durch Mikrowellen-unterstützte Säure-Katalyse

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle ...

Forschung

Chemie

Preparation of Hydrophobic Metal-Organic Frameworks via Plasma Enhanced Chemical Vapor Deposition of Perfluoroalkanes for the Removal of Ammonia

Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high surface area microporous materials, such as metal-organic frameworks (MOFs), unique challenges present themselves for PECVD treatments. Herein the protocol for development of a MOF that was previously unstable to humid conditions is presented. The protocol describes the synthesis of Cu-BTC (also known as HKUST-1), the treatment of Cu-BTC with PECVD of perfluoroalkanes, the aging of materials under humid conditions, and the subsequent ammonia microbreakthrough experiments on milligram quantities of microporous materials. Cu-BTC has an extremely high surface area (~1,800 m2/g) when compared to most materials or surfaces that have been previously treated by PECVD methods. Parameters such as chamber pressure and treatment time are extremely important to ensure the perfluoroalkane plasma penetrates to and reacts with the inner MOF surfaces. Furthermore, the protocol for ammonia microbreakthrough experiments set forth here can be utilized for a variety of test gases and microporous materials.

Herein the procedures for plasma enhanced chemical vapor deposition of perfluoroalkanes on microporous materials such as metal-organic frameworks to enhance their stability and hydrophobicity are described. Furthermore, breakthrough testing of milligram quantities of samples is described in detail.

Herstellung von hydrophoben Metall-organische Gerüste über Plasma Enhanced Chemical Vapor Deposition von Perfluoralkanen für die Beseitigung von Ammoniak

Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high ...

Ultrahigh Density Array of Vertically Aligned Small-molecular Organic Nanowires on Arbitrary Substrates

In recent years &pi;-conjugated organic semiconductors have emerged as the active material in a number of diverse applications including large-area, low-cost displays, photovoltaics, printable and flexible electronics and organic spin valves. Organics allow (a) low-cost, low-temperature processing and (b) molecular-level design of electronic, optical and spin transport characteristics. Such features are not readily available for mainstream inorganic semiconductors, which have enabled organics to carve a niche in the silicon-dominated electronics market. The first generation of organic-based devices has focused on thin film geometries, grown by physical vapor deposition or solution processing. However, it has been realized that organic nanostructures can be used to enhance performance of above-mentioned applications and significant effort has been invested in exploring methods for organic nanostructure fabrication.	
A particularly interesting class of organic nanostructures is the one in which vertically oriented organic nanowires, nanorods or nanotubes are organized in a well-regimented, high-density array. Such structures are highly versatile and are ideal morphological architectures for various applications such as chemical sensors, split-dipole nanoantennas, photovoltaic devices with radially heterostructured "core-shell" nanowires, and memory devices with a cross-point geometry. Such architecture is generally realized by a template-directed approach. In the past this method has been used to grow metal and inorganic semiconductor nanowire arrays. More recently &pi;-conjugated polymer nanowires have been grown within nanoporous templates. However, these approaches have had limited success in growing nanowires of technologically important &pi;-conjugated small molecular weight organics, such as tris-8-hydroxyquinoline aluminum (Alq3), rubrene and methanofullerenes, which are commonly used in diverse areas including organic displays, photovoltaics, thin film transistors and spintronics.	
Recently we have been able to address the above-mentioned issue by employing a novel "centrifugation-assisted" approach. This method therefore broadens the spectrum of organic materials that can be patterned in a vertically ordered nanowire array. Due to the technological importance of Alq3, rubrene and methanofullerenes, our method can be used to explore how the nanostructuring of these materials affects the performance of aforementioned organic devices. The purpose of this article is to describe the technical details of the above-mentioned protocol, demonstrate how this process can be extended to grow small-molecular organic nanowires on arbitrary substrates and finally, to discuss the critical steps, limitations, possible modifications, trouble-shooting and future applications.

We report a simple method for fabricating an ultrahigh density array of vertically ordered small-molecular organic nanowires. This method allows for synthesis of complex heterostructured hybrid nanowire geometries, which can be inexpensively grown on arbitrary substrates. These structures have potential applications in organic electronics, optoelectronics, chemical sensing, photovoltaics and spintronics.

Ultrahigh Density Array von vertikal ausgerichteten Klein-molekulare organische Nanodrähte auf beliebige Untergründe

In  recent years &pi;-conjugated  organic semiconductors have emerged as the active material in a number of  diverse applications including large-area, ...

Ingenieurwesen

Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The silica-encapsulated metal oxide nanoparticles are then carburized in a methane/hydrogen atmosphere at temperatures over 800 &#176;C to form silica-encapsulated early transition metal carbide nanoparticles. During the carburization process, the silica shells prevent the sintering of adjacent carbide nanoparticles while also preventing the deposition of excess surface carbon. Alternatively, the silica-encapsulated metal oxide nanoparticles can be nitridized in an ammonia atmosphere at temperatures over 800 &#176;C to form silica-encapsulated early transition metal nitride nanoparticles. By adjusting the reverse microemulsion parameters, the thickness of the silica shells, and the carburization/nitridation conditions, the transition metal carbide or nitride nanoparticles can be tuned to various sizes, compositions, and crystal phases. After carburization or nitridation, the silica shells are then removed using either a room-temperature aqueous ammonium bifluoride solution or a 0.1 to 0.5 M NaOH solution at 40-60 &#176;C. While the silica shells are dissolving, a high surface area support, such as carbon black, can be added to these solutions to obtain supported early transition metal carbide or nitride nanoparticles. If no high surface area support is added, then the nanoparticles can be stored as a nanodispersion or centrifuged to obtain a nanopowder.

A &#8220;removable ceramic coating method&#8221; is presented in visual format for the synthesis of non-sintered and metal-terminated monometallic and bimetallic early transition metal carbide and nitride nanoparticles with tunable sizes and crystal structures.

Umkehrmikroemulsion-vermittelte Synthese von Monometallische und Bimetall frühes Übergangsmetall Carbide und Nitride Nanopartikel

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The ...

Experimental Protocol to Investigate Particle Aerosolization of a Product Under Abrasion and Under Environmental Weathering

The present article presents an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental weathering, which is a fundamental element to the approach of nanosafety-by-design of nanostructured products for their durable development. This approach is basically a preemptive one in which the focus is put on minimizing the emission of engineered nanomaterials' aerosols during the usage phase of the product's life cycle. This can be attained by altering its material properties during its design phase without compromising with any of its added benefits. In this article, an experimental protocol is presented to investigate the nanosafety-by-design of three commercial nanostructured products with respect to their mechanical solicitation and environmental weathering. The means chosen for applying the mechanical solicitation is an abrasion process and for the environmental weathering, it is an accelerated UV exposure in the presence of humidity and heat. The eventual emission of engineered nanomaterials is studied in terms of their number concentration, size distribution, morphology and chemical composition. The purpose of the protocol is to study the emission for test samples and experimental conditions which are corresponding to real life situations. It was found that the application of the mechanical stresses alone emits the engineered nanomaterials' aerosols in which the engineered nanomaterial is always embedded inside the product matrix, thus, a representative product element. In such a case, the emitted aerosols comprise of both nanoparticles as well as microparticles. But if the mechanical stresses are coupled with the environmental weathering, the experimental protocol reveals then the eventual deterioration of the product, after a certain weathering duration, may lead to the emission of the free engineered nanomaterial aerosols too.

In this article, an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental weathering is presented. Results on the emission of engineered nanomaterials, in the form of aerosols are presented. The specific experimental set-up is described in detail.

Versuchsprotokoll Particle Aerosolisierung eines Produktes unter Abrieb und unter Umwelt Verwitterung zur Untersuchung

The present article presents an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental ...

Nanothermite with Meringue-like Morphology: From Loose Powder to Ultra-porous Objects

The goal of the protocol described in this article is to prepare aluminothermic compositions (nanothermites) in the form of porous, monolithic objects. Nanothermites are combustible materials made up of inorganic fuel and an oxidizer. In nanothermite foams, aluminum is the fuel and aluminum phosphate and tungsten trioxide are the oxidizing moieties. The highest flame propagation velocities (FPVs) in nanothermites are observed in loose powders and FPVs are strongly decreased by pelletizing nanothermite powders. From a physical standpoint, nanothermite loose powders are metastable systems. Their properties can be altered by unintentional compaction induced by shocks or vibrations or by the segregation of particles over time by settling phenomena, which originates from the density differences of their components. Moving from a powder to an object is the challenge that must be overcome to integrate nanothermites in pyrotechnic systems. Nanothermite objects must have both a high open porosity and good mechanical strength. Nanothermite foams meet both of these criteria, and they are prepared by dispersing a nano-sized aluminothermic mixture (Al/WO3) in orthophosphoric acid. The reaction of aluminum with the acid solution gives the AlPO4 &#34;cement&#34; in which Al and WO3 nanoparticles are embedded. In nanothermite foams, aluminum phosphate plays the dual role of binder and oxidizer. This method can be used with tungsten trioxide, which is not altered by the preparation process. It could probably be extended to some oxides, which are commonly used for the preparation of high performance nanothermites. The WO3-based nanothermite foams described in this article are particularly insensitive to impact and friction, which makes them far safer to handle than loose Al/WO3 powder. The fast combustion of these materials has interesting applications in pyrotechnic igniters. Their use in detonators as primers would require the incorporation of a secondary explosive in their composition.

This manuscript describes the synthesis of combustible aluminophosphate matrices by the reaction of orthophosphoric acid (H3PO4) with aluminum nanopowder. When this reaction is carried out with excess aluminum in the presence of tungsten trioxide nanopowder, it leads to a solid, porous nanothermite foam.

Nanothermit mit Baiser-ähnliche Morphologie: aus losen Puder auf Ultra-poröse Objekte

The goal of the protocol described in this article is to prepare aluminothermic compositions (nanothermites) in the form of porous, monolithic objects. ...

Simultaneous Multi-surface Anodizations and Stair-like Reverse Biases Detachment of Anodic Aluminum Oxides in Sulfuric and Oxalic Acid Electrolyte

After reporting on the two-step anodization, nanoporous anodic aluminum oxides (AAOs) have been widely utilized in the versatile fields of fundamental sciences and industrial applications owing to their periodic arrangement of nanopores with relatively high aspect ratio. However, the techniques reported so far, which could be only valid for mono-surface anodization, show critical disadvantages, i.e., time-consuming as well as complicated procedures, requiring toxic chemicals, and wasting valuable natural resources. In this paper, we demonstrate a facile, efficient, and environmentally clean method to fabricate nanoporous AAOs in sulfuric and oxalic acid electrolytes, which can overcome the limitations that result from conventional AAO fabricating methods. First, plural AAOs are produced at one time through simultaneous multi-surfaces anodization (SMSA), indicating mass-producibility of the AAOs with comparable qualities. Second, those AAOs can be separated from the aluminum (Al) substrate by applying stair-like reverse biases (SRBs) in the same electrolyte used for the SMSAs, implying simplicity and green technological characteristics. Finally, a unit sequence consisting of the SMSAs sequentially combined with SRBs-based detachment can be applied repeatedly to the same Al substrate, which reinforces the advantages of this strategy and also guarantees the efficient usage of natural resources.

A protocol for fabricating nanoporous anodic aluminum oxides via simultaneous multi-surfaces anodization followed by stair-like reverse biases detachments is presented. It can be applied repeatedly to the same aluminum substrate, exhibiting a facile, high-yield, and environmentally clean strategy.

Gleichzeitige Multi-Oberfläche Anodizations und Treppe-wie umgekehrte Vorurteile Ablösung der anodische Aluminium Oxide in Schwefelsäure und Oxalsäure-Elektrolyten

After reporting on the two-step anodization, nanoporous anodic aluminum oxides (AAOs) have been widely utilized in the versatile fields of fundamental ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three preparation methods are described: (a) the incorporation of metal salts into silica or alumina wet gels using an impregnation method; (b) the incorporation of metal salts into alumina wet gels using a co-precursor method; and (c) the addition of metal nanoparticles directly into a silica aerogel precursor mixture. The methods utilize a hydraulic hot press, which allows for rapid (&#60;6 h) supercritical extraction and results in aerogels of low density (0.10 g/mL) and high surface area (200-800 m2/g). While the work presented here focuses on the use of copper salts and copper nanoparticles, the approach can be implemented using other metal salts and nanoparticles. A protocol for testing the three-way catalytic ability of these aerogels for automotive pollution mitigation is also presented. This technique uses custom-built equipment, the Union Catalytic Testbed (UCAT), in which a simulated exhaust mixture is passed over an aerogel sample at a controlled temperature and flow rate. The system is capable of measuring the ability of the catalytic aerogels, under both oxidizing and reducing conditions, to convert CO, NO and unburned hydrocarbons (HCs) to less harmful species (CO2, H2O and N2). Example catalytic results are presented for the aerogels described.

Here we present protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms. Methods for preparing materials using copper salts and copper-containing nanoparticles are featured. Catalytic testing protocols demonstrate the effectiveness of these aerogels for three-way catalysis applications.

Herstellung und Prüfung von katalytischen Aerogelen über schnelle überkritische Extraktion vorbereitet

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...

Solvothermal Synthesis of MIL-96 and UiO-66-NH2 on Atomic Layer Deposited Metal Oxide Coatings on Fiber Mats

Metal-organic frameworks (MOFs), which contain reactive metal clusters and organic ligands allowing for large porosities and surface areas, have proven effective in gas adsorption, separations, and catalysis. MOFs are most commonly synthesized as bulk powder, requiring additional processes to adhere them to functional devices and fabrics that risk decreasing the powder porosity and adsorption capacity. Here, we demonstrate a method of first coating fabrics with metal oxide films using atomic layer deposition (ALD). This process creates conformal films of controllable thickness on each fiber, while providing a more reactive surface for MOF nucleation. By submerging the ALD coated fabric in solution during solvothermal MOF synthesis, the MOFs create a conformal, well-adhered coating on the fibers, resulting in a MOF-functionalized fabric, without additional adhesion materials that may block MOF pores and functional sites. Here we demonstrate two solvothermal synthesis methods. First, we form a MIL-96(Al) layer on polypropylene fibers using synthetic conditions that convert the metal oxide to MOF. Using initial inorganic films of varying thicknesses, diffusion of the organic linker into the inorganic allows us to control the extent of MOF loading on the fabric. Second, we perform a solvothermal synthesis of UiO-66-NH2 in which the MOF nucleates on the conformal metal oxide coating on polyamide-6 (PA-6) fibers, thereby producing a uniform and conformal thin film of MOF on the fabric. The resulting materials can be directly incorporated into filter devices or protective clothing and eliminate the maladroit qualities of loose powder.

Solvothermal Synthesis of MIL-96 and UiO-66-NH2 on Atomic Layer Deposited Metal Oxide Coatings on Fiber Mats

Metal-organic frameworks are effective in gas storage and heterogeneous catalysis, but typical synthesis methods result in loose powders that are difficult to incorporate into smart materials. We demonstrate a method of first coating fabrics with ALD metal oxides, resulting in conformal films of MOF on the fabrics during solvothermal synthesis.

Solvothermal Synthese von MIL-96 und UiO-66-NH2 auf atomarer Ebene hinterlegt Metall-Oxid-Beschichtungen auf Fasermatten

Metal-organic frameworks (MOFs), which contain reactive metal clusters and organic ligands allowing for large porosities and surface areas, have proven ...

Electrophoretic Crystallization of Ultrathin High-performance Metal-organic Framework Membranes

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and non-porous supports (polymer, ceramic, metal, carbon, and graphene). We developed a novel crystallization technique, which is termed the ENACT approach: the electrophoretic nuclei assembly for the crystallization of highly intergrown thin films (ENACT). This approach allows for a high density of heterogeneous nucleation of MOFs on a chosen substrate via the electrophoretic deposition (EPD) directly from the precursor sol. The growth of well-packed MOF nuclei leads to a highly intergrown polycrystalline MOF film. We show that this simple approach can be used for the synthesis of thin, intergrown zeolite imidazole framework (ZIF)-7 and ZIF-8 films. The resulting 500 nm-thick ZIF-8 membranes show a considerably high H2 permeance (8.3 x 10-6 mol m-2 s-1 Pa-1) and ideal gas selectivities (7.3 for H2/CO2, 15.5 for H2/N2, 16.2 for H2/CH4, and 2655 for H2/C3H8). An attractive performance for C3H6/C3H8 separation is also achieved (a C3H6 permeance of 9.9 x 10-8 mol m-2 s-1 Pa-1 and a C3H6/C3H8 ideal selectivity of 31.6 at 25 &#176;C). Overall, the ENACT process, owing to its simplicity, can be extended to synthesize intergrown thin films of a wide range of nanoporous crystalline materials.

A simple, reproducible, and versatile approach for the synthesis of intergrown, polycrystalline metal-organic framework membranes on a wide range of unmodified porous and non-porous supports is presented.

Elektrophoretische Kristallisation von ultradünnen Hochleistungs-Metall-organischen Rahmen Membranen

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and ...