Macroporous and mesoporous silica materials and method of manufacture

Abstract

A method may fill mesopores of silica microspheres with blocking liquid. A method may bond the silica microspheres with a colloidal silica nanosol comprising silica nanoparticles to form a paste. A method may shape the paste. A method may dry the paste to form the macroporous and mesoporous silica solid. An object may be manufactured using the method.

Description

Atty Docket No. TUOE.P2011WO / 00679172MACROPOROUS AND MESOPOROUS SILICA MATERIALS AND METHOD OF MANUFACTURERELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 750,348, filed January 28, 2025 and entitled “Molded Macroporous and Mesoporous Silica Materials and Method of Manufacture”, which is incorporated by reference in its entirety.BACKGROUND

[0002] Mesoporous silica materials may have use as stationary phases for catalysts and for thermal storage, sorption, and filtration and in batteries; for applications it is desirable that the mesoporous material have defined pore size and distribution with defined, and often high, surface area.

[0003] Mesoporous materials by definition have pore sizes between 2 and 50 nanometers. An existing synthesis can form mesoporous silica microspheres.SUMMARY

[0004] A macro-mesoporous material is formed by binding silica mesoporous microspheres together into macroscopic solids having useful shapes. Silica microspheres may be bound together with a silica nanosphere suspension or nanosol while protecting pores of the mesoporous microspheres from being filled or obstructed by the silica nanospheres.

[0005] In some aspects, the techniques described herein relate to a method of manufacturing a macroporous and mesoporous solid consisting primarily of silica including: filling mesopores of silica microspheres with blocking liquid; bonding the silica microspheres with a colloidal silica nanosol including silica nanoparticles to form a paste; shaping the paste; and drying the paste to form the macroporous and mesoporous silica solid.

[0006] In some aspects, the techniques described herein relate to an object including: silica having both macropores and mesopores; the silica including mesoporous silica microspheres bound together, a majority of mesopores of the mesoporous silica microspheres being unobstructed.Atty Docket No. TUOE.P2011WO / 00679172BRIEF DESCRIPTION OF THE FIGURES

[0007] Figure 1 is a flow chart of a method 100 of manufacturing a macroporous and me soporous solid, in embodiments.

[0008] Figs. 2 and 3 are a scanning electron micrograph of an object formed with the claimed method, showing bonded mesoporous silica microspheres of diameter 9-16 micrometers.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0009] Embodiments herein provide for the production of macro-mesoporous silica is demonstrated without the use of templates by gluing mesoporous silica microspheres (MSMs) to each other using silica nanosols. The building blocks are powdery dry MSMs and colloidal silica nanosol solutions. In embodiments, particle sizes of the MSMs are around 9 - 16 micrometers (pm) and of the silica nanoparticles in the nanosols are around 1 - 2 nanometers (nm). In alternative embodiments, the silica nanoparticles of the nanosols are between one and ten nanometers diameter. In a first alternative embodiment the MSMs may have particle size between ten to seventy five micrometers, in a second alternative embodiment the MSMs may have particle size from seventy five to five hundred micrometers, this the MSMs generally may have size between 9 and 500 pm. It should be appreciated that other sizes of MSM and nanoparticles may be utilized without departing from the scope hereof.

[0010] Fig. 1 shows a flow chart of a method 100 of manufacturing a macroporous and mesoporous solid, in embodiments.

[0011] In block 102, water is added to MSMs to fill the mesopores in the MSMs to yield wetted MSMs. The water may be deionized and may fill the mesopores by capillary action. Block 102 thereby preventing infiltration of the mesopores in the MSM by the nanosol dispersion. The deionized water serves as a blocking liquid to fill the mesopores and prevent infiltration of nanosol solution. In an embodiment of block 102, the amount of added water is at least approximately 100% of the mesopore volume of the MSMs. In an embodiment of block 102 the amount of added water is at least approximately 105% of the mesopore volume of the MSMs. In an embodiment of block 102, the amount of added water is at least approximately 110% of the mesopore volume of MSMs. Block 102 may include stirring the MSMs to absorb most of the added water into their mesopores.

[0012] In block 104, a colloidal silica nanosol solution is prepared. In an embodiment of block 104, a colloidal silica nanosol solution containing a ratio from 0.05 to 0.2 g silicaAtty Docket No. TUOE.P2011WO / 00679172nanoparticles per ml is prepared. In an embodiment, a ratio of from 1- 1.2 ml of the nanosol solution is used for each 1 g dry MSMs. Other ratios may be used without departing from scope hereof.

[0013] In block 106, the nanosol solution of block 104 is mixed with the wetted MSMs of block 102, resulting in a colloidal paste.

[0014] In block 108, the colloidal paste is shaped to yield a macro-mesoporous silica solid. In an embodiment of block 108, the colloidal paste is shaped by being poured into a mold of desired size and shape where it is dried at room or higher temperatures (e.g., 40°C and 60 °C) in an oven. In an embodiment of block 108, shaping the colloidal paste into an object is performed by extruding the colloidal paste and drying the extruded shapes or depositing the colloidal paste through an extruder of a three-dimensional (3D) printer and drying the extruded paste.

[0015] Block 108 may include a drying sub-step. During drying of block 108, the silica nanosols form connection points between MSMs effectively gluing them together into a hierarchically porous solid. More specifically, during the drying process, the water content of the colloidal solution mixture is reduced, producing menisci around the contact points of MSMs. The nano-sol concentration in this meniscus continuously rises and induces a water condensation reaction between nano-sols and nano-sol-MSM surface. This gelation of silica nano-sols forms the new silica layer on the contact points of MSMs, which chemically bonds the MSMs together. Techniques for modulating particle packing, such as pressurization or ultrasonication, can be applied before or during drying.

[0016] In block 110, which may be optional, the produced macro-mesoporous silica solid is further strengthened. In one example of operation of block 110, the produced macro-mesoporous silica solid of block 108 is mechanically by exposure to high temperatures (sintering) to strengthen the macro-mesoporous silica solid.

[0017] The resulting silica assembly contains bimodal porosity of nm-sized mesopores and pm-sized macropores. Mesopores originate from MSMs and their connection points and macropores originate from empty spaces between MSM packing. The multiscale morphology and pore contents can be controlled using different mold types (block 108), MSMs (block 102), nanosols (block 104), and production conditions (block 106, 110).

[0018] A particular embodiment has been performed multiple times, using 100 mg to 20 g of MSM powder and the colloidal silica nanosol solution in corresponding proportions. Silica assemblies have been produced in the shapes of mm- and cm-sized tablets according to mold shapes, other shapes are readily obtained by using appropriate molds.Atty Docket No. TUOE.P2011WO / 00679172

[0019] Figures 2 and 3 depict scanning electron microscope (SEM) of an example object manufactured using method 100, in an embodiment. The SEM analysis showed the structure of the produced macroscopic silica solids. MSMs were chemically bonded with a new silica layer on the contact points. Macropore channels between packed MSMs and mesopores in MSMs were shown.

[0020] Macropores were evaluated with Mercury Intrusion Porosimetry (MIP) analysis. Macropore channels had a narrow size distribution around 3-4 pm, and packing density was around 60%.

[0021] After sintering, the silica solid has good mechanical stability for manual handling and similar usage.

[0022] For a particular experimental embodiment, the preservation of mesopores in silica solids was evaluated by N2 adsorption analysis. The mesopore volume of an MSM building block was 0.89 ml / g. Mesopore volume after the preparation of silica solid was 0.85 ml / g, and 0.8 ml / g after sintering of solid. These results indicated that the majority of mesopores in MSM were preserved. The BET surface area of the MSMs was 310 m2 / g, and the silica solid had a surface area of 300-315 m2 / g. After sintering, it was 264 m2 / g, representing a reduction of about 15% of silica surface area; the sintered objects formed by the particular experimental embodiment thus having surface area between 260 and 290 square meters per gram.

[0023] The objects thus comprise bound MSMs with 80%-90% of mesopores unobstructed in the bound mesoporous silica microspheres; thus most mesopores in the bound silica microspheres are unobstructed.

[0024] The produced silica solids are primarily silica that contains mesopores (mesoporous silica microspheres) and macropores (spaces between packed microspheres). Pore sizes and pore size distributions are controlled by selection of pore sizes of the mesoporous silica microspheres and silica nanoparticles as building blocks. Even when doped, the produced silica solids consist primarily of silica.

[0025] The systems and methods herein may include additional modifications without departing from scope hereof. For example, in certain applications, such as but not limited to catalytic applications, the silica solids can be functionalized with guest materials introduced into the MSMs before binding the MSMs into the objects (e.g., before block 106) or by introducing the functional guest materials into the silica solid after binding (e.g., after block 106) the MSMs together with the nanosol. The catalytic function of the silica solids can be determined by the type of guest materials.Atty Docket No. TUOE.P2011WO / 00679172

[0026] As another example application, such as but not limited to thermal energy storage applications, the silica solids may be functionalized by impregnation with guest materials after binding (e.g., after block 106) the MSMs together with the nanosol.

[0027] Examples of potential applications of the silica solids are heat storage media with salt hydrates, catalysts, CO2 capture media with CO2 absorbing chemicals, and others.Combination Of Features:

[0028] (Al) In an embodiment of a first aspect hereof, a method of manufacturing a macroporous and mesoporous solid consisting primarily of silica includes: filling mesopores of silica microspheres with blocking liquid; bonding the silica microspheres with a colloidal silica nanosol comprising silica nanoparticles to form a paste; shaping the paste; and drying the paste to form the macroporous and mesoporous silica solid.

[0029] (A2) In the embodiment (Al), the silica microspheres having mesopore size between two and fifty nanometers.

[0030] (A3) In the embodiment (Al), the silica microspheres having size between nine and five hundred micrometers.

[0031] (A4) In the embodiment (Al), the silica microspheres having sizes between nine and sixteen micrometers.

[0032] (A5) In the embodiment (Al), the silica microspheres having sizes between ten and seventy-five micrometers.

[0033] (A6) In the embodiment (Al), the silica microspheres having sizes between seventy-five and five hundred micrometers.

[0034] (A7) In any embodiment (Al) through (A6), the silica nanoparticles having diameter between one and ten nanometers.

[0035] (A8) In any embodiment (Al) through (A7), further comprising sintering the mesoporous silica solid.

[0036] (A9) In any embodiment (Al) through (A8), the filling the mesopores of the silica microspheres with blocking liquid including adding blocking liquid of at least 100% of a mesopore volume of the silica microspheres and stirring the microspheres.

[0037] (A10) In any embodiment (Al) through (A9), wherein 1 to 1.2 ml nanosol solution containing from 0.05 to 0.2g silica nanoparticles is used for each 1g of dry MSMs.

[0038] (Al 1) In any embodiment (Al) through (A 10), the shaping being performed by molding the paste.Atty Docket No. TUOE.P2011WO / 00679172

[0039] (A 12) In any embodiment (Al) through (A 10), the shaping being performed by extruding the paste.

[0040] (A13) In any embodiment (Al) through (A10), the shaping being performed by depositing the paste with an extruder of a three-dimensional printer.

[0041] (Bl) In an embodiment of a second aspect hereof, an object includes: silica having both macropores and mesopores; the silica including mesoporous silica microspheres bound together, a majority of mesopores of the mesoporous silica microspheres being unobstructed.

[0042] (B2) In the embodiment (Bl), the silica microspheres having sizes between nine and sixteen micrometers and the macropores have sizes between 3 and 4 micrometers

[0043] (B3) In any embodiment (Bl) or (B2), the object being sintered, the silica microspheres having mesopore size between two and fifty nanometers.

[0044] (B4) In any embodiment (Bl) or (B2), the silica microspheres having size between one of: nine and five hundred micrometers; nine and sixteen micrometers; ten and seventy-five micrometers; or seventy-five and five hundred micrometers.

[0045] (B5) In any embodiment (B 1) through (B4), the mesoporous silica microspheres bound together via silica nanoparticles.

[0046] (B6) In any embodiment (B5), the silica nanoparticles having diameter between one and ten nanometers.

[0047] (B7) In any embodiment (Bl) through (B6), the object being formed by a mold, extruded, or 3D printed.

[0048] Changes may be made in the above methods and systems without departing from the scope hereof. It should thus be noted that the matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover all generic and specific features described herein, as well as all statements of the scope of the present method and system, which, as a matter of language, might be said to fall therebetween.

Claims

Atty Docket No. TUOE.P2011WO / 00679172CLAIMSWhat is claimed is:

1. A method of manufacturing a macroporous and mesoporous solid consisting primarily of silica comprising:fdling mesopores of silica microspheres with blocking liquid;bonding the silica microspheres with a colloidal silica nanosol comprising silica nanoparticles to form a paste;shaping the paste; anddrying the paste to form the macroporous and mesoporous silica solid.

2. The method of claim 1, the silica microspheres having mesopore size between two and fifty nanometers.

3. The method of claim 1, the silica microspheres having size between nine and five hundred micrometers.

4. The method of claim 1, the silica microspheres having sizes between nine and sixteen micrometers.

5. The method of claim 1, the silica microspheres having sizes between ten and seventy-five micrometers.

6. The method of claim 1, the silica microspheres having sizes between seventy-five and five hundred micrometers.

7. The method of any of claims 1 through 6, the silica nanoparticles having diameter between one and ten nanometers.

8. The method of any of claims 1 through 7, further comprising sintering the mesoporous silica solid.

9. The method of any of claims 1 through 8, the filling the mesopores of the silica microspheres with blocking liquid including adding blocking liquid of at least 100% of a mesopore volume of the silica microspheres and stirring the microspheres.Atty Docket No. TUOE.P2011WO / 0067917210. The method of any of claims 1 through 9, wherein 1 to 1.2 ml nanosol solution containing from 0.05 to 0.2g silica nanoparticles is used for each 1g of dry MSMs.

11. The method of any of claims 1 through 10, the shaping being performed by molding the paste.

12. The method of any of claims 1 through 10, the shaping being performed by extruding the paste.

13. The method of any of claims 1 through 10, the shaping being performed by depositing the paste with an extruder of a three-dimensional printer.

14. An object comprising: silica having both macropores and mesopores; the silica including mesoporous silica microspheres bound together, a majority of mesopores of the mesoporous silica microspheres being unobstructed.

15. The object of claim 14, the silica microspheres having sizes between nine and sixteen micrometers and the macropores have sizes between 3 and 4 micrometers16. The object of claim 14 or 15, the object being sintered.the silica microspheres having mesopore size between two and fifty nanometers.

17. The object of claim 14 or 15, the silica microspheres having size between one of:nine and five hundred micrometers;nine and sixteen micrometers;ten and seventy-five micrometers; orseventy-five and five hundred micrometers.

18. The object of any of claims 14 through 17, the mesoporous silica microspheres bound together via silica nanoparticles.

19. The object of claim 18, the silica nanoparticles having diameter between one and ten nanometers.

20. The object of any of claims 14 through 19, the object being formed by a mold, extruded, or 3D printed.

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