WO2020149818A1 - Croissance d'hydrogel/aérogel assistée par un sel - Google Patents

Croissance d'hydrogel/aérogel assistée par un sel Download PDF

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Publication number
WO2020149818A1
WO2020149818A1 PCT/US2019/013425 US2019013425W WO2020149818A1 WO 2020149818 A1 WO2020149818 A1 WO 2020149818A1 US 2019013425 W US2019013425 W US 2019013425W WO 2020149818 A1 WO2020149818 A1 WO 2020149818A1
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Prior art keywords
aerogel
salt
liquid medium
hydrogel
particulates
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PCT/US2019/013425
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English (en)
Inventor
Jing Kong
Xiang JI
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Massachusetts Institute Of Technology
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Priority to PCT/US2019/013425 priority Critical patent/WO2020149818A1/fr
Publication of WO2020149818A1 publication Critical patent/WO2020149818A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0066—Use of inorganic compounding ingredients
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/0091—Preparation of aerogels, e.g. xerogels
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
    • C01B33/157—After-treatment of gels
    • C01B33/158—Purification; Drying; Dehydrating
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/28—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2201/00—Foams characterised by the foaming process
    • C08J2201/04—Foams characterised by the foaming process characterised by the elimination of a liquid or solid component, e.g. precipitation, leaching out, evaporation
    • C08J2201/05—Elimination by evaporation or heat degradation of a liquid phase
    • C08J2201/0504—Elimination by evaporation or heat degradation of a liquid phase the liquid phase being aqueous
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2205/00—Foams characterised by their properties
    • C08J2205/02—Foams characterised by their properties the finished foam itself being a gel or a gel being temporarily formed when processing the foamable composition
    • C08J2205/022—Hydrogel, i.e. a gel containing an aqueous composition

Definitions

  • Aerogels have various applications due to their high surface area and low densities. Creating aerogels from various materials, however, has remained a challenge. For example, to date, only limited types of materials have been made into "aerogel" structures. These materials include metal oxide aerogels (e.g ., S1O2 and AI2O3), carbon material aerogels [such as carbon, carbon nano tubes (CNTs), and graphene]; and, more recently, semiconducting chalcogenide aerogels (e.g., GdS, GdSe, and PbTe).
  • metal oxide aerogels e.g ., S1O2 and AI2O3
  • carbon material aerogels such as carbon, carbon nano tubes (CNTs), and graphene
  • semiconducting chalcogenide aerogels e.g., GdS, GdSe, and PbTe.
  • aerogels are obtained through a sol- gel process with a suitable gelling agent precursor.
  • a suitable gelling agent precursor e.g., ethanol
  • TMOS tetramethyl orthosilicate
  • TEOS tetraethyl orthosilicate
  • a hydrolysis reaction forms particles of silicon dioxide, which may form a sol solution.
  • the oxide suspension then undergoes condensation reactions, which result in the creation of metal oxide bridges (M-O-M bridges or M-OH-M bridges) linking the dispersed colloidal particles.
  • Carbon aerogels are made by subjecting gel precursor to supercritical drying and subsequent pyrolysis of an RF aerogel at high temperature. Because this cross-linking reaction is specific only to a selected group of materials, the number of materials that may be used to form aerogels is limited.
  • U.S. Patent No. 9,208,919 B2 is directed to methods for fabricating aerogel from a variety of materials.
  • fabrication of the aerogel includes the following steps: (A) increasing a concentration of a suspension comprising a gel precursor under a condition that promotes formation of a gel, wherein the gel precursor comprises particulates having an asymmetric geometry; and (B) removing a liquid from the gel to form an aerogel, wherein the aerogel and the gel have substantially the same geometry.
  • fabrication of the aerogel includes the following steps: (A) subjecting a suspension comprising a gel precursor comprising particulates to sonication and/ or filtering; (B) forming the suspension into a gel using hydro-thermal synthesis; and (G) removing a liquid from the gel to form an aerogel, wherein at least some of the particulates have an aspect ratio of at least 50.
  • a method for producing an aerogel using a salt and the resulting aerogel are described herein, where various embodiments of the product and methods may include some or all of the elements, features and steps described below.
  • the resulting aerogel can be produced with lower density and better pressure performance (with a reduced pressure difference across a filter formed of the aerogel) in comparison with an aerogel from a similar process but without an added salt.
  • an aerogel can be produced by forming a gel precursor, comprising (a) a liquid medium, (b) a salt dissolved in the liquid medium, and (c) particulates suspended in the liquid medium, wherein the salt increases the density of the liquid medium.
  • the gel precursor is heated to form a hydrogel from the particulates in the liquid medium via hydrothermal synthesis.
  • the liquid medium can then be removed from the gel to form the aerogel.
  • FIG. 1 is a photograph of hydrogels 12 made from a solution with no KG1 salt (left) and 5M of KG1 salt (right).
  • FIG. 2 is a schematic illustration of hydrogel formation showing, from left-to- right: (a) insoluble particles 16 dispersed in solution in a liquid medium 14 in which salt 15 is dissolved, (b) nanowires 18 growing out of the particles 16, (c) nano wires 18 continuing to grow and becoming connected, and (d) formation of a hydrogel 12 in the form of a three-dimensional (3D) network of nanowires 18.
  • Percentages or concentrations expressed herein can be in terms of weight or volume. Processes, procedures and phenomena described below can occur at ambient pressure ⁇ e.g., about 50-120 kPa— for example, about 90-110 kPa) and temperature ⁇ e.g., -20 to 50°G— for example, about 10-35°G) unless otherwise specified.
  • first, second, third, etc. may be used herein to describe various elements, these elements are not to be limited by these terms. These terms are simply used to distinguish one element from another. Thus, a first element, discussed below, could be termed a second element without departing from the teachings of the exemplary embodiments.
  • spatially relative terms such as“above,”“below,”“left,”“right,”“in front,” “behind,” and the like, may be used herein for ease of description to describe the relationship of one element to another element, as illustrated in the figures. It will be understood that the spatially relative terms, as well as the illustrated configurations, are intended to encompass different orientations of the apparatus in use or operation in addition to the orientations described herein and depicted in the figures. For example, if the apparatus in the figures is turned over, elements described as“below” or“beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term,“above,” may encompass both an orientation of above and below.
  • the apparatus may be otherwise oriented ⁇ e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
  • the term,“about,” means within ⁇ 10% of the value recited.
  • each subrange and each individual value between the upper and lower ends of the range is contemplated and therefore disclosed.
  • an element when referred to as being“on,” “connected to,”“coupled to,”“in contact with,” etc., another element, it may be directly on, connected to, coupled to, or in contact with the other element or intervening elements may be present unless otherwise specified.
  • the various components identified herein can be provided in an assembled and finished form; or some or all of the components can be packaged together and marketed as a kit with instructions (e.g ;, in written, video or audio form) for assembly and/ or modification by a customer to produce a finished product.
  • kit with instructions e.g ;, in written, video or audio form
  • a method of making a composition comprising an aerogel may include adding a salt and increasing a concentration of a suspension comprising a gel precursor under a condition that promotes formation of a hydrogel. Subsequently, the liquid in the hydrogel may be removed such that an aerogel is formed.
  • the hydrogel and the aerogel may have substantially the same geometry.
  • Adding a non-reactive salt 15 that dissolves into the liquid medium 14 increases the density of the liquid medium 14 and, therefore, reduces the propensity of denser 3-D gel networks 12 to settle toward the bottom of the liquid medium 14, as shown in FIG. 1.
  • the non-reactive salt 15 e.g., a potassium or sodium salt
  • the salt concentration can be, e.g, in a range from 50% of its saturation point up to the saturation point.
  • the particles 16 can have a composition selected from, e.g., T1O2, V2O3, or graphene and can have a particle size of, e.g., 10 nm to 100 pm.
  • the liquid medium 14 can include water and either (a) an organic precursor (that includes the structural composition of the hydrogel) and a reactant that releases the structural composition to form the hydrogel or (b) a reactant ⁇ e.g., a hydroxide, such as KOH or NaOH) that reacts with T1O2 to produce the structural composition ⁇ e.g., K2T18O17) of the hydrogel.
  • the organic precursor can be, e.g., titanium isopropoxide, Ti ⁇ OCH(CH3)2 ⁇ 4, and the reactant can be sulfuric acid.
  • the gel precursor described herein may be any of a wide variety of materials, depending on the type of aerogel desired.
  • the methods described herein are versatile and may be employed to make a variety of types of aerogel material.
  • the precursor may contain a metal, a compound, a semiconductor, a carbon-containing material, or combinations thereof.
  • One feature of at least one embodiment described herein is that the methods described herein allow gel (and, finally, aerogel) to be formed with a relative low concentration of the precursor material.
  • the metal may be any metal, including noble metal and transition metal.
  • a noble metal may be gold, silver, platinum, copper, and the like.
  • a transition metal may be any element in Groups 3-12 of the Periodic Table.
  • the term, "element,” as used herein, refers to the elements found on the Periodic Table.
  • a transition metal may be Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Gr, Mo, W,
  • the metal may be silver.
  • the compound may refer to any of a variety of compounds depending on the applications.
  • the compound may be an oxide, a nitride, a
  • An oxide may be a metal oxide (e.g ;, alumina, titania, iron oxide, zinc oxide, manganese oxide, alkali-metal oxide, alkali-earth metal oxide, or any of the metals described above).
  • the oxide may alternatively be a non-metal oxide, including silica.
  • the compound may alternatively be a metal nitride, metal sulfide, including any of the aforementioned metals as the metal element.
  • the compound may be M0S2 , GdS, GdSe, Pb Te, or combinations thereof.
  • the nitride and sulfide may be a non-metal nitride and sulfide.
  • the compound may be a boron nitride (e.g., hexagonal boron nitride, or "h- BN").
  • the semiconductor may be selected from any known semiconductors.
  • the semiconductor may be an elemental semiconductor (only one element) or a compound semiconductor (more than one element).
  • the semiconductor may be an elemental semiconductor (only one element) or a compound semiconductor (more than one element).
  • the carbon-containing material may be any known structure that contains carbon atoms and can be provided in a powder form.
  • the material may be graphite, carbon nanotube, carbon nanowire, or graphene.
  • nanotubes may be single -walled carbon nanotubes, multi-walled carbon nanotubes, or both.
  • the gel precursor may contain a plurality of particulates.
  • particulates may have any geometry and need not be spherical.
  • the particulates described herein may have an asymmetric geometry (e.g, anisotropy) such that one dimension thereof is greater than the other; the dimensions described herein may refer to the diameter, length, width, and height of the particulate.
  • One feature of at least some embodiments described herein is the formation of aerogels using one dimensional (1-D) and/ or two-dimensional (2-D) materials using a general principle of gel formation based on shape asymmetry.
  • the particulates may be wire-like, tube-like (i.e., wire-like but hollow), sheet-like, flake -like, or any other shape.
  • the wire-like and tube-like particulates are herein regarded as being one- dimensional, while the sheet-like and flake-like particulats are herein regarded as being two-dimensionsl (with no more than a few atomic layers thickness). Because of the nanometer-length scale, in some embodiments, the particulates may be referred to as nanotubes, nanowires, or nanosheets, depending on the geometry; the particulates may comprise any of the afore-described materials.
  • the asymmetry may be described by, for example, an aspect ratio, which, in one embodiment herein, may refer to a ratio of the length to the diameter of a particulate (for a tubular-/ wire-like configuration) or to a ratio of the width or length to the thickness of a particulate (for a sheet-like configuration).
  • the particulates may have an aspect ratio of greater than about 1— e.g., greater than about 10, about 50, about 100, about 150, about 200, about 250, about 300, about 350, about 400, about 450, about 500, about 550, about 600, about 650, about 700, about 750, about 800, about 850, about 900, about 950, about 1000, about 2000, about 5000, about 1,0000, or more.
  • the aspect ratio may be higher (towards infinity) or lower (towards 1.1) than the aforedescribed values.
  • the aspect ratio may be between about 1 and about 1000— e.g., between about 10 and about 500, between about 100 and about 400, or between about 200 and about 300.
  • the particulates may have any size, ranging from nanometers to microns.
  • the size may refer to an average size in the case of a plurality of particulates.
  • the size may refer to any dimension, including length, width, height, thickness, diameter, etc., depending on the geometry.
  • the diameter of the particulate described herein may be less than about 500 nm— e.g., less than about 400 nm, about 300 nm, about 200 nm, about 100 nm, about 50 nm, about 20 nm, about 10 nm, about 5 nm, about 1 nm, or less.
  • the diameter may be between about 10 nm and about 500 nm— e.g., between about 20 nm and about 400 nm, between about 50 nm and about 300 nm, or between about 100 nm and about 200 nm.
  • Other dimensions, including the length, of the particulates may be calculated by the aspect ratio described above.
  • the length may be at least about 0.5 microns— e.g., at least about 1 micron, about 2 microns, about 4 microns, about 8 microns, about 16 microns, about 32 microns, or more.
  • the particulates contain silver and have an average diameter of about 113 nm and an average length of about 13.7 mhi.
  • the particulates contain silicon and have an average diameter of about 41 nm and an average length of about 5.2 pm. In some other embodiments, the particulates contain manganese oxide and have an average diameter of about 19 nm and an average length of about 8.4 pm.
  • a salt such as a potassium salt, is added to the gel precursor.
  • the salt increases the density of the liquid in the gel precursor.
  • Examples of high-solubility potassium salts that can be dissolved in water [at or near room temperature and 1- atmosphere pressure ( ⁇ 101 kPa)] up to the limits of their solubility and used in the gel precursor are listed in Table 1, below, where units of solubility are given in grams per 100 milliliters of water (g/100 ml).
  • the salt can be added up to the saturation point of the salt in the solution at room temperature. By avoiding exceeding the saturation point at room temperate, precipitation of the salt can be avoided.
  • KGL salt density
  • Table 2 The effect of salt (KGL) density on the density of the resulting aerogel for a sample in the form of a disc with a diameter of 1 inch (2.54 cm) and a thickness of 4 mm in a 10M KOH solution is shown in Table 2, as follows: Table2:
  • titania (T1O2) aerogels with a density less than about 41.9, 30.1, 21.2, or 17.3 mg/cm 3 can be formed by adding, respectively, at least 2, 3, 4, or 5 M of salt in the formation of the hydrogel.
  • T1O2 hydrogel/ aerogel hydrogel/aerogel growth from T1O2 (hydrogels and aerogels formed from T1O2 precursor may be herein referred to as T1O2 hydrogel/ aerogel) as an example.
  • T1O2 hydrogel/ aerogel P25 T1O2 nanoparticles are mixed into 10M KOH solution and subject to a 180 ⁇ 250°C hydrothermal reaction to form T1O2 hydrogel 12 ( e.g ;, via the following reaction: K2T18O17 +H2O) in a liquid medium 14, as shown in FIG. 1 (left).
  • the hydrogel is then dried to produce aerogel.
  • the density of hydrogel/ aerogel is hard to control for a given density of KOH solution, which determines the nanostructure of the hydrogel/aerogel.
  • KG1 as an example of high-solubility potassium salt (Table 1) to add into the solution, which endows a larger floating force for nanoparticles and thus produces a T1O2 hydrogel in FIG. 1 (right).
  • the hydrogels are freeze-dried to produce aerogels.
  • a no-KGl sample weights 100 mg and 5M KG1 sample weights 35 mg.
  • the densities are 49.34 mg/cm 3 for the sample without salt and 17.27 mg/cm 3 for the sample with salt.
  • compositions such as V2O3 or graphene, can be used in place of T1O2.
  • sodium salt can be used in place of potassium salt.
  • the salt is selected from at least one of a calcium salt, a lithium salt, a magnesium salt, a titanium salt, a manganese salt, a molybdenum salt, a tungsten salt, and an iron salt.
  • the particulates of the aerogels may be made using chemical vapor deposition (GVD), physical vapor deposition (PVD), and or hydrothermal or electrochemical deposition in anodic aluminum oxide (AAO) template.
  • hydrothermal synthesis may refer to a method of crystallizing a substance from hot water under high pressure.
  • the temperature of the water may be at about 50° G or more— e.g., about 60° G, about 70° G, about 80° G, about 90° G, or more.
  • the hydrogels formed by the methods described herein may be employed to form aerogels.
  • the hydrogel formation may be tailored by controlling a reaction time of the synthesis.
  • the synthesis may involve, for example, hydrothermal synthesis.
  • the reaction time may be tailored to be of any length of time, depending at least on the materials involved.
  • the reaction time may be at least about 5 minutes— e.g., at least about 10 minutes, about 20 minutes, about 30 minutes, about 60 minutes, about 2 hours, about 4 hours, about 6 hours, about 8 hours, about 10 hours, about 20 hours, about 40 hours, about 50 hours, about 60 hours, about 100 hours, about 120 hours, or longer.
  • the methods described herein may further include adding chemical coatings ⁇ e.g., polymer electrolyte) directly to the gel (skeleton) before the liquids are extracted from the hdrogel to form an aerogel.
  • chemical coatings e.g., polymer electrolyte
  • T1O2 nanowire dye-sensitized solar cell (“DSSC") devices may be constructed. The method may start with gel formation using T1O2 nanowire, and the gel may be made into a thin film on a glass slide. By soaking the T1O2 gel into a N-719-dye solution, a uniform layer of dye will be coated on the nanowire surface. Since the nanowire network is already formed, the contact region between the nanowires will not be coated so that the direct contact between the nanowires will be ensured.
  • chemical coatings ⁇ e.g., polymer electrolyte
  • DSSC dye-sensitized solar cell
  • the gel is soaked into a solution of polyethylene oxide (PEO) with KI/I2; the PEO with KI/I2 will be the electrolyte layer for the DSSG (a different solution).
  • electrodeposition of a thin layer (5-10 nm) of Pt is carried out, so the nanowires are coated with Pt serving as cathode.
  • super-critical-point drying (GPD) is carried out to obtain the coated aerogel.
  • GPD super-critical-point drying
  • the hydrogel formed according to the methods described above may be further dried to remove the liquid (solvent) from the hydrogel to form an aerogel. Drying may be carried out by any suitable drying techniques, depending on the materials involved. The techniques may include (i) freeze drying, (ii) supercritical- point drying (“GPD”), or both.
  • GPD supercritical- point drying
  • the liquid may be dried off slowly without causing the solid matrix in the gel to collapse from capillary action, as would happen with conventional evaporation techniques.
  • the 3-D structure of the particulates in the gel may be preserved in the aerogel upon the transition from gel into an aerogel.
  • the aerogel may contain a 3-D network of crystalline nanowires, nanosheets, nanotubes, or combinations thereof.
  • the level of preservation may account for minute discrepancies, so long as at least the majority ( e.g ., substantially all, or even all) of the network structure is preserved.
  • the geometry of the gel may also be preserved upon the transition into the aerogel.
  • the geometry in some embodiments herein may refer to shape, size (e.g., volume), and the like.
  • the aerogels produced according to the methods described in some embodiments herein may have desirable properties, including high surface areas and high thermal resistivity.
  • the aerogel may be hydrophobic or hydrophilic. In one embodiment, a portion of the aerogel is hydrophilic and another portion thereof is hydrophobic.
  • the aerogel may be elastic; in some embodiments, the aerogel exhibits superelasticity.
  • the aerogels described herein may have a much higher electrical conductivity than an aerogel produced by a conventional technique. For example, the presently described aerogels may have an electrical conductivity that is larger than a conventional aerogel by a factor of at least about 2, about 3, about 4, about 6, about 8, about 10, or more.
  • the aerogel may have an electrical conductivity that is at least about 200 S/ m— e.g, at least about 300 S/ m, about 400 S/m, about 600 S/m, about 800 S/m; about 1,000 S/m; about 0.5 x 10 4 S/m; about 1 x 10 4 S/m; about 0.5 x 10 5 S/ m; about 1 x 10 5 S/ m; about 0.5 x 10 6 S/ m; about 1 x 10 6 S/m; about 0.5 x 10 7 S/m; about 1 x 10 7 S/m, or more.
  • the aerogel has an electrical conductivity of at least 3 x 10 6 S/ m.
  • the aerogels produced according to the methods described in some embodiments herein may have a mesoporous microstructure, having high porosity and/ or high surface area (i.e., low density).
  • the mesoporous microstructure may be interconnected.
  • the pores may have any geometries. In some embodiments, the pores may be cylindrical, slit-shaped, or any other shape, or a combination of any of these.
  • the pore size is 11.85nm
  • the pore sized for an aerogel sample produced from a 5M KG1 solution is 15.48nm.
  • the properties of the aerogels may depend on the materials involved.
  • the aerogel when the particulates contain silver, the aerogel may have (i) an electrical conductivity of at least about 3 x 10 6 S/m, (ii) a density of less than or equal to about 90 mg/ cm 3 , or both.
  • the aerogels when the particulates contain single -wall carbon nanotubes, the aerogels may have (i) an electrical conductivity of at least about 300 S/m, (ii) a density of less than or equal to about 2.7 mg/ cm 3 , or both.
  • the aerogel when the particulates contain graphene, the aerogel may have (i) an electrical conductivity of at least about 400 S/ m, (ii) a density ofless than or equal to about 15 mg/cm 3 , or both.
  • aerogels described herein may be used in applications including filtration, catalysis, sensing, energy storage, solar cells, fuel cells, thermal insulation, ultra-light structural media, and many other applications.
  • the aerogel may be a part of an electronic component (of an electronic device).
  • the electronic component may be a capacitor, including a super-capacitor.
  • the afore-described aerogels produced via the foregoing methods can be used as a filter for catalysis and filtration of a fluid stream with entrained solids, wherein the aerogel can trap the solids as the fluid passes through the filter and can catalyzed reactions of
  • Such a filter can be used for a variety of applications, such as for removing viruses, bacteria, allergens, dust, combustion products, etc.
  • such a filter can be used, e.g., in a factory (e.g., positioned in the exhaust stream of a smokestack); in a motor vehicle (e.g, positioned in the engine exhaust stream leading to the tailpipe); or in the home, a building, a hospital, or a clean room ( e.g ., in a semiconductor fabrication lab or in a lab where biological processes are carried out) in an air-intake flow stream to provide clean air to any of these environments.
  • a factory e.g., positioned in the exhaust stream of a smokestack
  • a motor vehicle e.g, positioned in the engine exhaust stream leading to the tailpipe
  • a clean room e.g ., in a semiconductor fabrication lab or in a lab where biological processes are carried out
  • a gel precursor comprising (a) a liquid medium, (b) a salt dissolved in the liquid medium, and (c) particulates suspended in the liquid medium, wherein the salt increases the density of the liquid medium;
  • a single element or step may be replaced with a plurality of elements or steps that serve the same purpose.
  • those parameters or values can be adjusted up or down by l/100 th , l/50 th , l/20 th , l /10 th ,

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Abstract

Un aérogel est produit par formation d'un précurseur de gel, comprenant (a) un milieu liquide, (b) un sel dissous dans le milieu liquide, et (c) des particules en suspension dans le milieu liquide, le sel augmentant la densité du milieu liquide. Le précurseur de gel est chauffé pour former un hydrogel à partir des particules dans le milieu liquide par synthèse hydrothermale. Le milieu liquide est ensuite retiré du gel pour former l'aérogel.
PCT/US2019/013425 2019-01-14 2019-01-14 Croissance d'hydrogel/aérogel assistée par un sel WO2020149818A1 (fr)

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* Cited by examiner, † Cited by third party
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CN102923788A (zh) * 2012-11-09 2013-02-13 北京理工大学 一种四氧化三铁气凝胶的制备方法
US20130202890A1 (en) * 2012-02-03 2013-08-08 Jing Kong Aerogels and methods of making same
US20150068974A1 (en) * 2013-09-06 2015-03-12 The Massachusetts Institute Technology In-situ aerogels and methods of making same
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US20010033817A1 (en) * 1996-12-06 2001-10-25 Matthew T. Sander Aerogel honeycomb catalyst monoliths for selective catalytic reaction of gas phase chemical species
US20130202890A1 (en) * 2012-02-03 2013-08-08 Jing Kong Aerogels and methods of making same
CN102923788A (zh) * 2012-11-09 2013-02-13 北京理工大学 一种四氧化三铁气凝胶的制备方法
US20160030908A1 (en) * 2013-03-06 2016-02-04 Ecole Polytechnique Federale De Lausanne (Epfl) Titanium oxide aerogel composites
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3114514A1 (fr) * 2020-09-29 2022-04-01 Commissariat A L Energie Atomique Et Aux Energies Alternatives Utilisation d’aérogel à base de nanofils métalliques en tant que matériau filtrant pour le traitement de l’air, Cartouche à électrodes associée, Système de traitement de l’air associé.

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