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ultrasound-assisted exfoliation results to be a more vigorous process with smaller flakes being formed, while shear mixing is less effective but able to produce a more homogenous …
Micron and submicron-sized vermiculite lamellar particles with nanometric thickness (< 10 nm) were prepared by ultrasonic treatments (< 12 h) of aqueous and hydrogen peroxide …
In all the tests the exfoliation of the samples was higher when the reaction was carried out with H2O2 solution at 50% than at 30%, which agreed with that observed by Obut and Girgin (2002) for vermiculite. The exfoliation speed (thickness or volume/ time) of the samples Santa Olalla, Libby and Goiás increased with the concentration of H2O2 ...
Since the first case of vermiculite exfoliation was reported in 1960s, practice has repeatedly proved the feasibility of nanofluidic proton channels derived from ultrathin vermiculite sheets (VS ...
In this study vermiculite from Egypt was chemically activated by leaching with 0.5 M HCl solution or by treatment with 30% H 2 O 2 solution. ... in exfoliation when the pressure exceeds the ...
The vermiculite sample showed 2.8 and 5.6 times, respectively, the exfoliation ratio of the phlogopite samples, in accord with their water contents. Vermiculites and phlogopites can be exfoliated by chemical and thermal treatment methods to obtain chemically inert, adsorbent, fire-resistant, low-density materials with excellent thermal and ...
The ultrasound-assisted exfoliation and shear-mixing of a multi-phasic vermiculite in mild acidic aqueous solutions were employed to successfully obtain dispersions of mono- and …
The properties of vermiculite itself, the ability of vermiculite to react with heavy metals and the mechanism of interaction between them still have a large gap in simulation studies. Therefore, it is important to further simulation to explore the characteristics of vermiculite itself, the interaction relationship between vermiculite and heavy ...
The effect of ultrasounds on natural macroscopic vermiculite flakes has been studied. Conditions for the preparation of submicron vermiculite particles of narrow particle-size distribution by ...
Here, ultrasound-assisted exfoliation and shear-mixing of a multi-phasic vermiculite in mild acidic aqueous solutions were employed to successfully obtain dispersions of mono- and few-layer thick clay nanosheets.
The exfoliation characteristics of Karakoç phlogopite (KP), Phalaborwa phlogopite (PP) and Phalaborwa vermiculite (PV) with hydrogen peroxide were investigated.
Ali et al. [18] reported that solvent sono-exfoliation of vermiculite with sonication time of 5 h at room temperature promoted the production of sub-micro sized vermiculite particles. In addition, the authors further found ultrasound technique could prevent undesirable side effect as no crystal structure change was found during the delamination ...
Chemical treatments involving ion exchange cause gross one-dimensional swelling in water of single crystals of vermiculite minerals. A delicate balance of forces holds the individual silicate layers (10 angstroms thick) parallel to one another although separated by …
Microwave Exfoliation of Vermiculite and Phlogopite - Volume 51 Issue 4. To save this article to your Kindle, first ensure coreplatform@cambridge is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account.
1. Introduction. Currently, many different methods and processes (hydrothermal, chemical coprecipitation [], sol-gel synthesis, and sonochemical and mechanochemical synthesis, etc.) are used for nanocomposite material preparation.Hybrid antibacterial nanocomposite materials are specific examples of nanocomposite materials, which are increasingly in demand, especially in …
Vermiculite Exfoliation The Vermiculite Association Amsterdam 17 June 2016 . TORBED is a registered Trade Mark of Mortimer Technology Holdings Limited . Martin Groszek Managing Director Torftech Group energy to solids to energy. Overview • Some background to Torftech
Vermiculite (VMT) is a common layered silicate mineral with the main characteristics of natural, non-toxic, high expansion rate and negative charging, which is the main product of biotite and phlogopite altered by low temperature hydrothermal alteration [1], [2], and is mainly located in South Africa [3], Unite State [4], [5], Brazil [6] and China [7], [8].
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The mineral occurs in association with Feldspar, Quartz, Corundum, Garnet in intrusive pegmatite veins nearly 100 feet long. Vermiculite is a mineral of commercial significance due to its property of exfoliation when heated and has a wide spectrum of application in Thermal Insulation, Acoustical Insulation and Soil Conditioning.
VERMICULITE is the name given to a group of hydrated laminar minerals which are aluminium-iron-magnesium silicates, resembling mica in appearance. CRUDE VERMICULITE consists of thin, flat flakes containing microscopic layers of water. EXFOLIATION On being subjected suddenly to high temperatures (700°C to 1000°C) vermiculite flakes will
The ultrasound-assisted exfoliation and shear-mixing of a multi-phasic vermiculite in mild acidic aqueous solutions were employed to successfully obtain dispersions of mono- and …
"Vermiculite" is derived from the Latin word vermiculus (=small worm) which refers to the wormlike projections this mineral forms when subjected to high temperatures. Vermiculite is a hydrous 2:1 phyllosilicate similar in structure to mica, but has a lower layer charge, and contains hydrated exchangeable cations in the interlayers versus "non-exchangeable" K + in the …
Most of the published laboratory investigations of microwave exfoliation of vermiculite to date (Obut et al., 2003, Zhao et al., 2010, Marcos and Rodríguez, 2010a) have been carried out using ...
Lateral phase boundaries between vermiculite and mica layers, or vermiculite and chlorite layers are postulated to prevent or impede the escape of gas from a particle, resulting in exfoliation ...
For the last two decades, application of ultrasound in materials synthesis has been a very promising topic especially for the fabrication or modification of various nanomaterials. Simplicity, high efficacy, short reaction tenure along with power saving features are...
In all the tests the exfoliation of the samples was higher when the reaction was carried out with H 2 O 2 solution at 50% than at 30%, which agreed with that observed by Obut and Girgin (2002) for vermiculite. The exfoliation speed (thickness or volume/ time) of the samples Santa Olalla, Libby and Goiás increased with the concentration of H 2 ...
All work reported so far on microwave exfoliation of vermiculite has been limited to laboratory scale using domestic microwave ovens (2.45 GHz, power below 1200 W) and the route to scale up the ...
In recent, the exfoliation strategy to construct a two-dimensional (2D) structure (e.g., MoS 2, graphene, MXene) is a research hotspot in the layered materials science field [20], [21], [22].Especially in the adsorption and photocatalytic realm, the exfoliation method is able to enlarge the specific surface area as well as shorten the migration path of photogenerated …
When heated rapidly to between 870 and 1100 °C, the interlayer water is turned to steam and the pressure generated within the structure disrupts the vermiculite silicate layer by a process known as exfoliation (Marcos and Rodríguez, 2010, Obut and Girgin, 2002).Resulting from this process, its volume expands to several times that of the unprocessed material (Hillier …
Vermiculite is a low-cost phyllosilicate, which, due to its characteristics of stability, safety, abundant reserves, easy exfoliation, high porosity and specific surface area (Midgley and Midgley ...
