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METHOD FOR IN-SITU SYNTHESIS OF METAL ORGANIC FRAMEWORKS (MOFs), COVALENT ORGANIC FRAMEWORKS (COFs) AND ZEOLITE IMIDAZOLATE FRAMEWORKS (ZIFs), AND APPLICATIONS THEREOF

20210016245 ยท 2021-01-21

    Inventors

    Cpc classification

    International classification

    Abstract

    The present invention relates to method for the synthesis in-situ of the class of compounds known generally as MOFs (metal organic frameworks or organometallic compounds), COFs (covalent organic frameworks), and ZIFs (Zeolitic imidazolate framework), within and onto different types of substrates, and to the applications of such substrates having in-situ synthesized MOFs, COFs and ZIFs.

    Claims

    1. A method for the in situ synthesis of MOFs, COFs, or ZIFs, onto and within a porous substrate by contacting the porous substrate with a first solution and a second solution, wherein the first and second solutions are capable of forming the said MOFs, COFs, or ZIFs.

    2. A method as claimed in claim 1 wherein the porous substrate is contacted with the first solution and the second solution, sequentially in any order or simultaneously as a mixture of the two solutions.

    3. A method as claimed in claim 1 or 2 wherein the first solution and/or the second solution comprise a mixture of two or more solutions, wherein the resulting adsorbent synthesized in situ is either one or more MOFs, COFs, or ZIFs or a combination of one or more of MOFs, COFs or ZIFs with an inorganic adsorbent.

    4. A method as claimed in claim 1 to 3 wherein the contacting is done by dipping or soaking.

    5. A method as claimed in any preceding claim wherein dipping/soaking time, temperature, pressure, concentration, and viscosity for both the first solution and the second solution are optimized with or without use of enhancers or retarders.

    6. A method as claimed in any preceding claim wherein the ratio of the in situ synthesized adsorbent to substrate is in the range of 0.1 to 6 times by weight of the adsorbent to the bare substrate, preferably in the range of 0.5 to 4 times by weight of the bare substrate, and more preferably in the range of 1.5 to 3 times by weight of the bare substrate.

    7. A method as claimed in any preceding claim wherein the substrate is pretreated with a rigidifying agent selected from the group consisting of silica sol, alumina sol, polyvinyl alcohol, polyvinyl acetate, acrylate, water glass and any combination thereof.

    8. A method as claimed in any preceding claim wherein the substrate is washed after in situ synthesis to remove unreacted or excess starting material or byproducts formed during the synthesis, drying, and activation.

    9. A method as claimed in any preceding claim wherein the substrate is converted into a desired geometry after dipping in a first solution, followed by dipping/soaking the shaped substrate into a second solution to result in the in situ formation of the adsorbent.

    10. A method as claimed in any of claims 1 to 8 wherein the substrate is first shaped into a desired geometry, followed by sequential dipping of the shaped substrate into a first solution and a second solution or a mixture of the first and second solutions to result in the in situ formation of an adsorbent.

    11. A method as claimed in any preceding claim, wherein a dosing amount of titanium silicate is added to the first solution or the second solution prior to treatment of the substrate.

    12. A method as claimed in any preceding claim wherein the substrate is subjected to burn-off of substantially all organic binding material without affecting the adsorbent properties.

    13. A method as claimed in any preceding claim wherein the in situ synthesized MOF comprises any one of MIL-100(Fe), AIF, MOF-5, Cu-BTC, MIL-53, MIL-68, Mg-MOF-74, MIL-101(Cr), MOF 801, MOF 177, CAU-10H, MOF 808, IR-MOF-8, CPO-Ni(27), MOF 199, DMOF (Zn), DUT-4, and a combination thereof.

    14. A method as claimed in claim 1 to 12 wherein the COF formed in situ is selected from the group consisting of COF-202, COF-1, COF-5, PcPBBA, TpPa-1, TpPa-2, TpPa-NO2, TpPa-F4, TpBD, TpBD-(NO2), and a combination thereof

    15. A method as claimed in claim 1 to 12 wherein the ZIF is selected from the group consisting of ZIF-1, ZIF-7, ZIF-8, ZIF-35, ZIF-67, ZIF-69, ZIF-71, ZIF-90, ZIF-95 and ZIF-100, and a combination thereof.

    16. A method as claimed in any preceding claim wherein the substrate is a porous substrate selected from the group consisting of glass fibers, ceramic fibres, natural fibers, synthetic fibers, biosoluble fibers, pulp and any combination thereof, and if desired strengthened with 2 to 8% by weight of a rigidifying agent selected from the group consisting of silica sol, alumina sol, polyvinyl alcohol, polyvinyl acetate, and acrylate.

    17. A method as claimed in any preceding claim wherein the loaded substrate is dried at a temperature of up to 90 C.

    18. A method as claimed in any preceding claim wherein the substrate treated with both solutions is dried at a temperature in the range of 80 C. to 160 C.

    19. A method as claimed in any preceding claim wherein 0.25 to 15% by weight of an additive selected from the group consisting of xanthan gum, sodium alginate, hydroxypropylmethylcellulose, guar gum, starch, and ethylene glycol is added to the substrate via the solution containing the organic component.

    20. A method as claimed in any preceding claim wherein the organic linker used to impregnate the substrate is a bidentate or tridentate ligand selected from the group consisting of derived from a dicarboxylic acid, such as oxalic acid, tartaric acid, succinic acid, 1,4-butanedicarboxylic acid, 1,4-butene-dicarboxylic acid, 4-oxopyran-2,6-dicarboxylic acid, decanedicarboxylic acid, 1,8-heptadecanedicarboxylic acid, 1,6-hexanedicarboxylic acid, heptadecanedicarboxylic acid, acetylene dicarboxylic acid, 1,9-heptadecanedicarboxylic acid, 1,2-benzenedicarboxylic acid, 1,3-benzenedicarboxylic acid, 2,3-pyridinedicarboxylic acid, pyridine-2,3-dicarboxylic acid, 1,4-benzenedicarboxylic acid, p-benzenedicarboxylic acid, imidazole-2,4-dicarboxylic acid, 2-methylquinoline-3,4-dicarboxylic acid, quinoline-2,4-dicarboxylic acid, quinoxaline-2,3-dicarboxylic acid, 6-chloroquinoxaline-2,3-dicarboxylic acid, 1,3-butadiene-1,4-dicarboxylic acid, 4,4-diaminophenylmethane-3,3-dicarboxylic acid, quinoline-3,4-dicarboxylic acid, di imidedicarboxylic acid, pyridine-2,6-dicarboxylic acid, 2-methylimidazole-4,5-dicarboxylic acid, 7-chloro-4-hydroxyquinoline-2,8-dicarboxylic acid, thiophene-3,4-dicarboxylic acid, tetrahydropyran-4,4-dicarboxylic acid, perylene-3,9-dicarboxylic acid, 2-isopropylimidazole-4,5-dicarboxylic acid, perylenedicarboxylic acid, Pluriol E 200-dicarboxylic acid, 3,5-cyclohexadiene-1,2-dicarboxylic acid, octanedicarboxylic acid, pentane-3,3-carboxylic acid, 3,6-dioxaoctanedicarboxylic acid, 4,4-diamino-1,1-biphenyl-3,3-dicarboxylic acid, 4,4-diaminobiphenyl-3,3-dicarboxylic acid, benzidine-3,3-dicarboxylic acid, 1,1-binaphthyldicarboxylicacid, 1,4-bis(phenylamino)benzene-2,5-dicarboxylicacid, 7-chloro-8-methylquinoline-2,3-dicarboxylic acid, 1-anilinoanthraquinone-2,4-dicarboxylic acid, 1,4-bis(carboxymethyl)piperazine-2,3-dicarboxylic acid, phenylinanedicarboxylic acid, 7-choroquinoline-3,8-dicarboxylic acid, polytetrahydrofuran 250-dicarboxylic acid, 1-(4-carboxy)phenyl-3-(4-chloro)phenylpyrazoline-4,5-dicarboxylic acid, 1,4,5,6,7,7-hexachloro-5-norbornene-2,3-dicarboxylic acid, 1,3-dibenzyl-2-oxoimidazolidine-4,5-dicarboxylicacid, 1,4-cyclohexanedicarboxylic acid, naphthalene-1,8-dicarboxylic acid, 1,3-dibenzyl-2-oxoimidazolidine-4,5-cis-dicarboxylic acid, 2,2-biquinoline-4,4-dicarboxylic acid, 2-benzoylbenzene-1,3-dicarboxylic acid, pyridine-3,4dicarboxylic acid, 3,6,9-trioxaundecanedicarboxylic acid, Pluriol E 300 dicarboxylic acid, Pluriol E 400-dicarboxylic acid, hydroxybenzophenonedicarboxylic acid, Pluriol E 600-dicarboxylic acid, pyrazole-3,4-dicarboxylic acid, bis(4-aminophenyl)sulfone diimide-dicarboxylic acid, 5,6-dimethyl-2,3-pyrazinedicarboxylic acid, bis(4-aminophenyl) ether diimide-dicarboxylic acid, 2,3-pyrazinedicarboxylic acid, 4,4-diaminodiphenylmethane diimide-dicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,3-adamantanedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 8-methoxy-2,3-naphthalenedicarboxylic acid, 8-sulfo-2,3-naphthalenedicarboxylic acid, anthracene-2,3-dicarboxylic acid, 8-nitro-2,3-naphthalenecarboxylic acid, 2,3-diphenyl-p-terphenyl-4,4-dicarboxylic acid, (diphenyl ether)-4,4-dicarboxylic acid, 4(1H)-oxothiochromene-2,8-dicarboxylic acid, imidazole-4,5-dicarboxylic acid, 5-tert-butyl-1,3-benzenedicarboxylic acid, 7,8-quinolinedicarboxylic acid, 4,5-imidazoledicarboxylic acid, 1,3,5-benzenetricarboxylic acid, 1,3,5-tris(4-carboxyphenyl)benzene, and the heterocyclic aromatic organic compounds for in situ synthesis of ZIFs is selected from the group consisting of imidazole, benzimidazole, chlorobenzimidazole, nitroimidazole, 2-methylimidazole, and imidazole-2-carboxyaldehyde.

    21. A method as claimed in any preceding claim wherein the metal salt is selected from the group consisting of ferric nitrate, ferric chloride, ferrous chloride, chromium nitrate, chromium chloride, aluminium sulphate, aluminium chloride, aluminium bromide, aluminium hydrogensulfate, aluminium dihydrogen phosphate, aluminium monohydrogen phosphate, aluminium phosphate, aluminium nitrate, nickel acetate, zirconium oxychloride, zinc nitrate, zinc acetate, copper acetate, copper nitrate, cobalt nitrate and magnesium nitrate.

    22. A method as claimed in any preceding claim wherein the concentration of the metal salt in solution is in the range of 5% to 50% by weight of the solution.

    23. A method as claimed in any preceding claim wherein the solvent is selected from the group consisting of water, methanol, ethanol, n-propanol, iso-propanol, n-butanol, isobutanol, t-butanol, pentanol, hexanol, dimethyl sulfoxide, N,N-dimethyl formamide, N,N-diethyl formamide, toluene, acetonitrile, dioxane, N,N-dimethylacetamide, benzene, chlorobenzene, tetrahydrofuran, ethyl acetate, methyl ethyl ketone, pyridine, sulfolane, glycol, N-methylpyrrolidone, diethyl amine, triethyl amine, gamma-butyrolactone, cyclohexanol, acetylacetonate, mesitylene and other similar aqueous, non-aqueous, aliphatic, aromatic, organic, in-organic solvents and mixture thereof.

    24. A method as claimed in any preceding claim wherein the reaction temperature is in the range of 5 to 120 C., and the reaction time is in the range of 10 min to 24 hours.

    25. A porous substrate having MOFs, COFs, or ZIFs synthesized in situ onto and within the substrate, for use in gas separation membranes, dehumidification applications, drug delivery systems, energy storage devices, CO2 capture, sensors, lithium batteries.

    26. An adsorbent matrix wherein one or more adsorbents selected from the group consisting of MOFs, COFs, ZIFs, a combination thereof with an inorganic adsorbent, are synthesized in situ onto and within a substrate.

    27. An adsorbent matrix wherein one or more adsorbents selected from the group consisting of MOFs, COFs, ZIFs, a combination thereof with an inorganic adsorbent, are impregnated onto and within a substrate.

    28. An adsorbent matrix as claimed in claim 26 or 27 wherein the matrix is in the form of a honeycomb.

    29. An adsorbent matrix as claimed in claim 26 to 28 wherein the ratio of the adsorbent to matrix is in the range of 0.1 to 6 times by weight of the adsorbent to the bare substrate, preferably in the range of 0.5 to 4 times by weight of the bare substrate, and more preferably in the range of 1.5 to 3 times by weight of the bare substrate.

    30. An adsorbent matrix as claimed in claims 26 to 29 wherein the MOF comprises any one of MIL-100(Fe), AIF, MOF-5, Cu-BTC, MIL-53, MIL-68, Mg-MOF-74, MIL-101(Cr), MOF 801, MOF 177, CAU-10H, MOF 808, IR-MOF-8, CPO-Ni(27), MOF 199, DMOF (Zn), DUT-4, and a combination thereof.

    31. An adsorbent matrix as claimed in claims 26 to 29 wherein the COF is selected from the group consisting of COF-202, COF-1, COF-5, PcPBBA, TpPa-1, TpPa-2, TpPa-NO2, TpPa-F4, TpBD, TpBD-(NO2), and a combination thereof.

    32. An adsorbent matrix as claimed in claims 26 to 29 wherein ZIF is selected from the group consisting of ZIF-1, ZIF-7, ZIF-8, ZIF-35, ZIF-67, ZIF-69, ZIF-71, ZIF-90, ZIF-95 and ZIF-100, and a combination thereof.

    33. An adsorbent matrix as claimed in claims 26 to 32 wherein the substrate is a porous substrate selected from the group consisting of glass fibers, ceramic fibres, natural fibers, synthetic fibers, biosoluble fibers, pulp and any combination thereof, and if desired strengthened with 2 to 8% by weight of a rigidifying agent selected from the group consisting of silica sol, alumina sol, polyvinyl alcohol, polyvinyl acetate, and acrylate.

    34. An adsorbent matrix as claimed in claims 26 to 29 wherein the adsorbent is a combination of a MOF, COF or ZIF and an inorganic adsorbent.

    35. A method for the manufacture of an adsorbent matrix as claimed in any of claims 26 to 34 wherein one or more adsorbents selected from the group consisting of MOFs, COFs, ZIFs, a combination of one or more MOFs, COFs, ZIFs with an inorganic adsorbent are synthesized in situ thereon or impregnated thereon.

    36. A method as claimed in claim 35 wherein the in situ synthesis or impregnation is followed by washing to remove unreacted or excess starting material or byproducts formed during the synthesis, and, drying and/or activation.

    37. A method as claimed in claim 35 or 36 comprising dipping the substrate in a first solution, converting the dipped substrate into a shaped matrix, followed by dipping the shaped matrix into a second solution to result in in situ formation of an adsorbent selected from the group consisting of MOFs, COFs, ZIFs, a combination of one or more MOFs, COFs, ZIFs with an inorganic adsorbent.

    38. A method as claimed in claim 35 to 37 wherein the first solution or the second solution is a combination of two or more solutions.

    39. A method as claimed in claims 35 to 38 wherein the contacting with the first and second solutions can be sequential in any order or simultaneous with a mixture of the first and second solutions.

    40. A method as claimed in any of claims 35 to 39 wherein the adsorbent substrate is treated with a rigidifying agent.

    41. A method as claimed in claim 35 wherein the adsorbent is present in the form of a slurry, and wherein if desired the impregnation is carried out using a suitable binder selected from the group consisting of inorganic or organic binders.

    42. A method as claimed in claims 35 to 40 wherein the dipping/soaking time and concentration/viscosity for the adsorbent slurry at impregnation are optimized.

    43. A method for filtering an adsorbate from a fluid using an adsorbent laden matrix provided with an adsorbent selected from MOFs, COFs, ZIFs, a combination of one or more of MOFs, COF, ZIFs and an inorganic adsorbent provided thereon.

    44. A method as claimed in claim 43 wherein the fluid can be liquid or a gas, or a combination of liquids or a combination of gases.

    45. A method as claimed in claim 43 or 44 wherein the adsorbate can be a liquid or gas or a combination of liquids or a combination of gases.

    46. A method as claimed in claim 45 wherein the adsorbate is water vapour, CO2, VOCs and other gaseous matter and the adsorbent laden matrix is provided in a desiccant/adsorbent shaped wheel or a shaped matrix of any geometry.

    47. A desiccant wheel having an adsorbent matrix provided with an adsorbent selected from the group consisting of consisting of MOFs, COFs, ZIFs, a hybrid of one or more MOFs, COFs, ZIFs with an inorganic adsorbent, and any combination thereof provided thereon.

    48. A desiccant wheel as claimed in claim 47 wherein the said adsorbent is synthesized in situ onto and within the matrix or wherein the said adsorbent is impregnated in the matrix.

    Description

    BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

    [0061] FIG. 1a shows the water uptake capacity of various conventional inorganic adsorbents at different RH (source: Sorbent Systems/PNNL).

    [0062] FIG. 1b shows the water uptake capacity of various MOFs compared with silica gel at different RH (Source: PNNL).

    [0063] FIG. 1c shows adsorption and desorption curves of a specific S-type MOF (MOF-101) at different RH (Source: Janiak et al, Eur. J. Inorganic Chem., 2011/PNNL).

    [0064] FIG. 2a shows the water uptake capacity of various adsorbents at 75% RH at 25-C at different time intervals (Source: Sorbent Systems/PNNL) FIG. 2b shows water uptake capacity of a MOF (Cu-BTC) at 40% RH at room temperature and at different exposure times (Source: PNNL).

    [0065] FIG. 2c shows the water uptake capacity of two different adsorbents at 40% RH at room temperature at different exposure times (Source: PNNL).

    [0066] FIG. 3a shows the water uptake capacity of various conventional adsorbents at different activation conditions (Source: Sorbent Systems/PNNL).

    [0067] FIG. 3b shows the thermo-gravimetric analysis (TGA) curve of a MOF (Cu-BTC) (Source: PNNL).

    [0068] FIG. 3c shows the thermo-gravimetric analysis (TGA) curve of a MOF (CoCo) (Source: PNNL).

    [0069] FIGS. 1a to 1c, as listed above, demonstrate that MOF adsorption capacities are higher than conventional adsorbents/desiccants. FIG. 2a to 2c, as listed above, show higher adsorption rates (kinetics) for MOFs compared to conventional adsorbents/desiccants. FIGS. 3a to 3c, as listed above, show that MOFs have significantly lower desorption temperatures as compared to conventional adsorbents/desiccants, making them advantageous in terms of energy required for regeneration.

    [0070] FIG. 4a is an XRD image for aluminium fumarate prepared according to one embodiment of the present invention.

    [0071] FIG. 4b is an FTIR image for COF-1 prepared according to the method of the present invention.

    [0072] FIG. 4c is an XRD image for ZIF-1 prepared according to the method of the present invention.

    [0073] FIGS. 4a-4c, as listed above confirm that the material synthesized in situ are respectively a particular MOF, COF and ZIF, confirming the workability of the method of the present invention.

    [0074] FIG. 5a is a schematic depiction of the cross-sectional view of a porous flat substrate having a MOF synthesized in situ (onto and within the substrate), according to the method of the present invention.

    [0075] FIG. 5b is a schematic depiction of the perspective view of a porous flat substrate, in a sheet form, having a MOF synthesized in situ (onto and within the substrate), according to the method of the present invention.

    [0076] FIG. 6 are illustrative depictions of various matrix shapes wherein a MOF can be synthesized in situ (onto and within the porous substrate) which can be achieved according to the method of the present invention.

    [0077] FIG. 7 is an illustrative depiction of a honeycomb matrix typically used in fluid exchange/filtration devices, wherein a MOF is synthesized in situ (onto and within the porous substrate) which can be achieved according to the method of the present invention.

    [0078] FIG. 8 is a schematic depiction of the in situ synthesisation process according to the present invention showing manufacture of a honeycomb matrix with in situ synthesized aluminium fumarate by sequential dipping.

    [0079] FIG. 9 is a schematic depiction of the manufacture of a honeycomb rotor through a continuous process of synthesis of adsorbent simultaneous and in situ of the substrate passing through the continuously formed mixture of component A and B whereafter it is formed into a honeycomb substrate.

    [0080] FIG. 10 is a schematic depiction of the manufacture of a preformed honeycomb matrix having a MOF synthesized in situ (onto and within the porous substrate of the honeycomb) according to one embodiment of the invention.

    [0081] FIG. 11 is a schematic depiction of the manufacture of a honeycomb matrix rotor by impregnating the substrate in a slurry of aluminium fumarate and forming into a honeycomb rotor according to another embodiment of the present invention.

    [0082] FIG. 12 is a schematic depiction of a pre-prepared honeycomb matrix rotor impregnated by dipping in a slurry of aluminium fumarate according to one embodiment of the present invention.

    DETAILED DESCRIPTION OF THE INVENTION

    [0083] The following description sets out the method of the invention and the implementations required to achieve the embodiments referred to above. The description is illustrative and should not be construed as limiting the scope of the invention. Variations and modifications are possible without departing from the spirit and scope of the invention.

    [0084] The present invention in a first embodiment therefore provides a novel and inventive method for in situ synthesis of MOFs, COFs and/or ZIFs directly within and onto a substrate, irrespective of the industrial application, or the choice of substrate. As will be appreciated, eliminating or minimizing the dependence on binder systems, the choice of substrates etc., provides great flexibility in use and implementation of these materials.

    [0085] One advantage of this in-situ preparation method is that it enables providing MOFs/COFs/ZIFs within or onto a substrate in an amount of 0.5 to 6 the basis weight of the substrate. Additionally, the need for a binder system as is required in the prior art, is totally eliminated. The method of the invention enables the preparation of substrates having MOFs, COFs and ZIFs synthesized in situ without the additional steps of coating, curing, etc., that are required when MOF/COF/ZIF powders, prepared as powders, according to the prior art are used.

    [0086] The present invention provides a method for in situ synthesis of a metal organic framework, a covalent organic framework or a zeolite imidazolate framework within and onto a porous substrate, where all the material synthesized isfully active material except the substrate.

    [0087] The present invention also provides specific industrial applications wherein the in situ deposition of MOFs, COFs and/or ZIFs can be employed, including for example, humidity control applications, gas separation applications, gas storage, biodegradable filters, catalytic filters, Carbon recovery applications, sensing applications, energy storage/lithium battery applications, carbon capture, bio-alcohol recovery, drug delivery, etc.

    [0088] The method of the invention involves preparation of different metal organic frameworks, and zeolite imidazolate frameworks comprising of at least one bidentate organic compound coordinated to at least one metal ion, and in the case of a covalent organic framework at least one organic compound providing a framework which is covalently bonded with the second organic compound. The substrate may or may not be provided with water glass, silica sol or any inorganic or organic material that is used, for example, in substrate corrugation as a rigidifying agent. This is a function of a specific industrial application and is not critical to the working of in situ synthesis of this invention.

    [0089] The porous substrate in any desired shape or form can be made by selecting from one or more of: glass fibers, ceramic fibres, natural fibers, synthetic fibers, biosoluble fibers, pulp, etc. which allow use of the substrate, with or without additional processing, and synthesized material to 500 C. or higher depending on the thermal stability of the particular MOF/COF/ZIF.

    [0090] If desired, the substrate can be pre-treated with a rigidifying agent such as silica sol, alumina sol, polyvinyl alcohol, polyvinyl acetate, acrylate, or any other similar non-reactive material such as water glass.

    [0091] In the method of the invention, the substrate on which the MOF, COF or ZIF is to be synthesized in situ can be a substrate per se or a shaped matrix. The method essentially involves treating the substrate or matrix with a solution comprising monovalent, divalent or trivalent metal salt solution and treatment with a solution of a bidentateortridentate organic compound in solution under desired conditions of time and temperature to aid crystal formation in the case of MOFs. In the case of ZIFs the same method can be replicated replacing the bidentate or tridentate solution with a solution of a heterocyclic aromatic organic compound. The MOF or ZIF are formed in-situ within and onto the substrate at the point of treatment with a second solution. The MOF/ZIF component is not deposited but forms in-situ during reaction of the two solutions directly onto and within the substrate and without requiring a separate binder.

    [0092] The metal solution can be a solution of a single metal. If the desired MOF has to contain two or more metal ions, then the solution can be a co-solution of two or more different solutions of respective metal ions. Similarly, the use of a mixture of solutions enables the formation of different MOFs. As is evident, in the case of ZIFs where the need is for a zeolitic framework having two or more metal components, or a separate ZIFs, the metal solution can be a mixture of solutions of different metals.

    [0093] Similarly, the solution of the organic component can be a mixture of solutions of two or more organic linkers/ligands or solutions of two or more heterocyclic aromatic organic compound.

    [0094] A critical aspect of the present invention is the flexibility of approach during in situ synthesis. The contacting of the substrate with the first and second solutions can be sequential in any order, or simultaneous or even as a co-solution comprising a mixture of both first and second solutions. The rate of reaction (formation of the MOFs, COFs or ZIFs) can be controlled by the use of appropriate reaction accelerators or retardants.

    [0095] The conditions of time and temperature during the reaction (in situ formation) stage can be controlled in order to tailor the MOF/ZIF/COF loading onto the substrate or matrix. This again provides flexibility in customization of the substrate/matrix for a particular application.

    [0096] In another embodiment of the invention, the first or the second solution can be provided with other component(s) (such as water glass, inorganic acids), to enable the co-synthesis of the MOF, COF or ZIF with inorganic adsorbent(s). The inorganic adsorbent(s) so formed can be silica gel, and/or metal silicates, or a particular inorganic adsorbent.

    [0097] In a further embodiment of the invention, an inorganic material (such as zeolites) can be mixed with the first or the second solution such that in situ synthesised MOF, COF or ZIF entraps the inorganic material.

    [0098] In another embodiment of the invention, the substrate after treatment with the first solution is converted into the desired matrix form, and then treated with the second solution.

    [0099] In yet another embodiment, the substrate is treated sequentially or simultaneously with both the first and the second solutions and then converted into the desired matrix geometry.

    [0100] After the treatment with the reactant solutions (first solution and second solution), the substrate/matrix is washed and dried. The drying may be any conventional means such as a drying chamber or through natural drying. The treated substrate may be heated for the purpose of activation.

    [0101] The metal can be selected from the group consisting of iron, nickel, titanium, zirconium, chromium, aluminium, zinc, tin, lead, magnesium, copper, cobalt, and other monovalent, bivalent, or trivalent metals. The metal component can be used as metal per se or in the form of salts. Examples of the metal salt that can be used include ferric nitrate, ferric chloride, ferrous chloride, chromium nitrate, chromium chloride, aluminium sulphate, aluminium chloride, aluminium bromide, aluminium hydrogensulfate, aluminium dihydrogen phosphate, aluminium monohydrogen phosphate, aluminium phosphate, aluminium nitrate, nickel acetate, zirconium oxychloride, zinc nitrate, zinc acetate, copper acetate, copper nitrate, cobalt nitrate, magnesium nitrate, etc. The aluminium salt is preferably a substance that can provide an aluminium (III) ion. The metal salt can be present in the form of an alkoxide, acetonate, halide, sulfite, as a salt of an organic or inorganic, oxygen comprising acid or a mixture thereof. The alkoxide, for example is, a methoxide, ethoxide, n-propoxide, i-propoxide, n-butoxide, i-butoxide, t-butoxide or phenoxide. An acetonate is, for example, acetylacetonate. A halide is, for example, chloride, bromide or iodide. An organic, oxygen comprising acid is, for example, formic acid, acetic acid, propionic acid or another alkylmonocarboxylic acid. An inorganic oxygen comprising acid is, for example, sulfuric acid, sulfurous acid, phosphoric acid or nitric acid.

    [0102] The metal component when used in the present invention is usually in the form of an aqueous mixture. Alternatively, the metal salt can also be a suspension or solution in water, or a combination of water and an organic or inorganic solvent. The choice of solvent is dependent on the metal salt in question.

    [0103] The examples of solvents used are water, methanol, ethanol, n-propanol, iso-propanol, n-butanol, isobutanol, t-butanol, pentanol, hexanol, dimethyl sulfoxide, N,N-dimethyl formamide, N,N-diethyl formamide, toluene, acetonitrile, dioxane, N,N-dimethylacetamide, benzene, chlorobenzene, tetrahydrofuran, ethyl acetate, methyl ethyl ketone, pyridine, sulfolane, glycol, N-methylpyrrolidone, diethyl amine, triethyl amine, gamma-butyrolactone, cyclohexanol, acetylacetonate, mesitylene and other similar aqueous, non-aqueous, aliphatic, aromatic, organic, in-organic solvents and mixture thereof.

    [0104] The bidentate or tridentate organic compound can be derived from a dicarboxylic acid, such as oxalic acid, tartaric acid, succinic acid, 1,4-butanedicarboxylic acid, 1,4-butene-dicarboxylic acid, 4-oxopyran-2,6-dicarboxylic acid, decanedicarboxylic acid, 1,8-heptadecanedicarboxylic acid, 1,6-hexanedicarboxylic acid, heptadecanedicarboxylic acid, acetylene dicarboxylic acid, 1,9-heptadecanedicarboxylic acid, 1,2-benzenedicarboxylic acid, 1,3-benzenedicarboxylic acid, 2,3-pyridinedicarboxylic acid, pyridine-2,3-dicarboxylic acid, 1,4-benzenedicarboxylic acid, p-benzenedicarboxylic acid, imidazole-2,4-dicarboxylic acid, 2-methylquinoline-3,4-dicarboxylic acid, quinoline-2,4-dicarboxylic acid, quinoxaline-2,3-dicarboxylic acid, 6-chloroquinoxaline-2,3-dicarboxylic acid, 1,3-butadiene-1,4-dicarboxylic acid, 4,4-diaminophenylmethane-3,3-dicarboxylic acid, quinoline-3,4-dicarboxylic acid, di imidedicarboxylic acid, pyridine-2,6-dicarboxylic acid, 2-methylimidazole-4,5-dicarboxylic acid, 7-chloro-4-hydroxyquinoline-2,8-dicarboxylic acid, thiophene-3,4-dicarboxylic acid, tetrahydropyran-4,4-dicarboxylic acid, perylene-3,9-dicarboxylic acid, 2-isopropylimidazole-4,5-dicarboxylic acid, perylenedicarboxylic acid, Pluriol E 200-dicarboxylic acid, 3,5-cyclohexadiene-1,2-dicarboxylic acid, octanedicarboxylic acid, pentane-3,3-carboxylic acid, 3,6-dioxaoctanedicarboxylic acid, 4,4-diamino-1,1-biphenyl-3,3-dicarboxylic acid, 4,4-diaminobiphenyl-3,3-dicarboxylic acid, benzidine-3,3-dicarboxylic acid, 1,1-binaphthyldicarboxylic acid, 1,4-bis(phenylamino)benzene-2,5-dicarboxylic acid, 7-chloro-8-methylquinoline-2,3-dicarboxylic acid, 1-anilinoanthraquinone-2,4-dicarboxylic acid, 1,4-bis(carboxymethyl)piperazine-2,3-dicarboxylic acid, phenylinanedicarboxylic acid, 7-choroquinoline-3,8-dicarboxylic acid, polytetrahydrofuran 250-dicarboxylic acid, 1-(4-carboxy)phenyl-3-(4-chloro)phenylpyrazoline-4,5-dicarboxylic acid, 1,4,5,6,7,7-hexachloro-5-norbornene-2,3-dicarboxylic acid, 1,3-dibenzyl-2-oxoimidazolidine-4,5-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, naphthalene-1,8-dicarboxylic acid, 1,3-dibenzyl-2-oxoimidazolidine-4,5-cis-dicarboxylic acid, 2,2-biquinoline-4,4-dicarboxylic acid, 2-benzoylbenzene-1,3-dicarboxylic acid, pyridine-3,4dicarboxylic acid, 3,6,9-trioxaundecanedicarboxylic acid, Pluriol E 300 dicarboxylic acid, Pluriol E 400-dicarboxylic acid, hydroxybenzophenonedicarboxylic acid, Pluriol E 600-dicarboxylic acid, pyrazole-3,4-dicarboxylic acid, bis(4-aminophenyl)sulfone diimide-dicarboxylic acid, 5,6-dimethyl-2,3-pyrazinedicarboxylic acid, bis(4-aminophenyl) ether diimide-dicarboxylic acid, 2,3-pyrazinedicarboxylic acid, 4,4-diaminodiphenylmethane diimide-dicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,3-adamantanedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 8-methoxy-2,3-naphthalenedicarboxylic acid, 8-sulfo-2,3-naphthalenedicarboxylic acid, anthracene-2,3-dicarboxylic acid, 8-nitro-2,3-naphthalenecarboxylic acid, 2,3-diphenyl-p-terphenyl-4,4-dicarboxylic acid, (diphenyl ether)-4,4-dicarboxylic acid, 4(1H)-oxothiochromene-2,8-dicarboxylic acid, imidazole-4,5-dicarboxylic acid, 5-tert-butyl-1,3-benzenedicarboxylic acid, 7,8-quinolinedicarboxylic acid, 4,5-imidazoledicarboxylic acid, or derived from a tricarboxylic acid such as 1,3,5-benzenetricarboxylic acid, 1,3,5-tris(4-carboxyphenyl)benzene, and the like.

    [0105] Viscosity enhancers/additives are added to increase the loading onto the substrate. Examples of additives include xanthan gum, sodium alginate, hydroxypropylmethylcellulose, guar gum, starch, ethylene glycol, etc.

    [0106] In the case of ZIFs, the organic ligand is usually selected from the group of heterocyclic aromatic organic compounds consisting of imidazole, benzimidazole, chlorobenzimidazole, nitroimidazole, 2-methylimidazole, imidazole-2-carboxyaldehyde, etc. This may be dissolved in an organic solvent or in water. The metal component is usually a metal such as zinc, or cobalt or iron, in salt form. The actual form used may be powder form or may be dissolved in a solvent whether organic or water or inorganic.

    [0107] In the case of covalent organic frameworks, the materials include 1,3,5-triformylphloroglucinol, 1,4-benzenediboronic acid, tert-butylsilanetriol and p-phenylenediamine for example. The components can be dissolved in solvents such as 1,2-dichloroethane, 1,4-dioxane, toluene, mesitylene-dioxane mixture, etc.

    [0108] The significance of the method of the invention is that in most cases the sequence of impregnation to reaction is not reactant specific. Thus, for example, either group of materials can be impregnated into the porous substrate, and then the substrate treated with the other group to form the MOF/COF or ZIF in situ. This also allows for control of loading as well as depth of loading, as well as uniformity of loading, and also effectively does away with the need to use a binder system to adhere the MOF to the substrate.

    [0109] While the following discussion refers to certain specific MOFs, it is not to be interpreted in a limiting manner since the method of in situ formation can be utilized for formation of non-exemplified MOFs, COFs or ZIFs as well with suitable process modifications.

    [0110] In the case of MIL-100(Fe), the preparation method comprises mixing 1,3,5-benzene tricarboxylic acid in an organic solvent such as ethanol or dimethyl formamide. A second solution of an iron salt such as ferric nitrate is preparedagain as an aqueous solution or as a solution in an organic solvent such as methanol. The porous substrate can be treated with either solution followed by treatment with the second solution. The sequence of treatment is not critical. The second treatment is carried out at a specific time and temperature so as to form the MOF in situ and to a loading of up to 6GSM or more on the porous substrate basis weight.

    [0111] In the case of aluminium fumarate, the porous metal organic framework is formed by the coordination of the fumarate ions with Aluminium (III) ions. The framework is formed in-situ onto and within the substrate. The source of bidentate fumarate ions is fumaric acid and that of aluminium (III) ion is aluminium sulphate. The metal organic framework produced is a result of reaction of aluminium compound and bidentate organic compound in aqueous medium in presence of a base at different reaction temperatures and reaction times.

    [0112] The porous framework contains at least one bidentate ligand based on fumaric acid and a trivalent metal salt based on aluminium ions. The powdered aluminium fumarate formed is adhered onto the surface of a substrate by using suitable inorganic or organic binders. Water is used as a solvent in the reaction. Simple alkali metal hydroxides, preferably sodium hydroxide or potassium hydroxide are used.

    [0113] In another embodiment of the invention, MOFs, COFs and ZIFs prepared in situ, or by prior art techniques, are also useful in heat exchange or adsorption applications. For shaped matrices, e.g. honeycomb matrix, the use of MOF, COF or ZIF prepared in situ, or by dry/wet methods of the prior art, or by a method of coating/depositing have shown tremendous advantages of lower regeneration temperatures, and hence lower energy usage, faster moisture uptake, and very high adsorption uptake, over use of prior art zeolites or silica gel techniques.

    [0114] The present invention also provides a method for the formation by in situ synthesis or by deposition, of metal organic framework in or on heat exchanger elements that are suitable for low, medium or high humidity applications, and to such humidity exchanger elements.

    [0115] The applicants herein have earlier shown the advantages of in situ synthesis of metal silicates microporous desiccants in honeycomb structures used in humidity control applications, as compared to generated and then coated systems. The use of in situ synthesized MOFs, or COFs or ZIFs in a honeycomb structure can be expected to provide greater advantages than coated MOFs/COFs or ZIFs, particularly since the depth of formation will be higher than prior art. Preliminary studies have shown synthesized/deposited active material at levels of up to 6GSM as compared to prior art claimed (but not established or substantiated) figures of up to 100 GSM as disclosed in U.S. Pat. No. 8,697,191.

    [0116] The present invention also relates to a humidity exchanger element suitable for low, medium and high humidity applications, produced by laminating corrugated paper and liner paper with many small channels, having active Metal Organic Framework (MOF) synthesized in-situ or deposited using porous or non-porous substrate. The material, in powder or granular form, is also suitable for use in humidity exchange. A significant advantage of the method of the invention is that it enables the user to choose the level of loading of the in situ synthesized MOF, COF or ZIF depending on his/her specific need. Thus, even loadings as low as 0.2% to as high as 600% of adsorbent (based on bare weight of substrate) can be chosen depending on specific industrial application, and practiced.

    [0117] The above disclosure is non-limiting and variations and modifications are possible without departing from the spirit and scope of the invention in any manner. The following examples set out the various embodiments of the invention involving the in situ synthesis of MOFs, COFs and ZIFs using the method of the invention.

    EXAMPLES

    [0118] All the following examples utilize glass fiber substrate having porosity capable of holding up to 6 to 8 times of water glass of its own weight. The steps of drying where carried out were using natural drying. Activation is done at 140 C. for 2 hours.

    Example 1: In Situ Synthesis of Aluminium Fumarate

    A: Using Untreated Substrate

    Example 1a: Using Potassium Hydroxide without Additive

    [0119] Solution A is prepared in three parts by dissolving potassium hydroxide in water, followed by adding fumaric acid under stirring, wherein the ratios of the constituents are different as set out in Table 1a below. Solution B is prepared by dissolving 100 gms of aluminium sulphate in 500 ml of water. The substrate has a basis weight of 33 GSM. Solution B and the substrate are also divided into three separate partseach to be used with one respective part of solution A. The substrate is soaked in a respective part of Solution A at room temperature and then dried naturally. The dried substrate is then treated with Solution B at a temperature of 80-C and for a time period of 15 minutes to initiate the reaction. After completion of the reaction, the substrate is washed with water to remove any by-products and then subjected to natural drying, followed by activation in a drying chamber. The loading percentage of in situ synthesized MOF (aluminium fumarate) on the substrate was studied. The quantities of the ingredients in solution A and the results of the tests are given in Table 1a below.

    TABLE-US-00001 TABLE 1a Solution-A Fumaric Adsorbent % water Sl KOH acid Water loading % GSM of adsorption No. (g) (g) (mL) on substrate Substrate:Adsorbent Adsorbent at RH-50 1 123 110.6 260 75 57:43 31.5 30 2 118 105 260 49 67:33 20 27 3 99.2 99.3 250 85 54:46 34 30

    Example 1b: Using Potassium Hydroxide with Additive and Increasing the Number of Dippings

    [0120] Solution A is prepared as three parts, each by dissolving 120 gms of potassium hydroxide in 450 ml of water followed by addition of 99 gms of fumaric acid under stirring, followed by addition of 2 gm of xanthan gum as additive. Solution B is prepared by dissolving 100 gms of aluminium sulphate in 200 ml of water. The substrate is of 33 GSM basis weight. The substrate parts are subjected to soaking in Solution A parts with different number of dippings (2, 3, and 4 respectively) and with intermediate drying to result in an enhanced loading of component/reactant A, followed by a final drying, before being soaked in the respective part of Solution B to initiate in situ formation of the aluminium fumarate on the substrates. The reaction temperature is 75-C and the reaction time is 30 minutes. The substrates are then each washed to remove by-products followed by natural drying and by activation in a drying chamber. The loading percentage of in situ synthesized MOF and the effect of successive dippings on loading percentage were studied. The water adsorption at 50% RH was studied using Belsorp Aqua 3. The results are given in Table 1b below. The 35% adsorption correlates very well with the highest literature-reported adsorption of 33-38% for aluminium fumarate at 50% RH.

    TABLE-US-00002 TABLE 1b Adsorbent % water Sl No. of loading % Substrate:Ad- GSM of adsorption No. dipping on substrate sorbent adsorbent at RH-50 1 2 104 49:51 33.6 32.3 2 3 158 38:62 54 30.3 3 4 197 33:67 67 34.7

    Example 1c: Using Potassium Hydroxide with Silica Sol and Additive

    [0121] The protocol of Example 1a was followed except that seven parts of Solution A were prepared with differing amounts of potassium hydroxide and xanthan gum additive. Silica sol is also added to the solution A under continuous mixing. Solution B is identical to Example 1b above. Substrate comprised of basis weight of 33GSM. The substrate parts were dipped in respective parts of the Solution Bat differing temperatures and times. This was followed by washing, natural drying and activation in a drying chamber. The effect of differing amounts of reactants in Solution A, reaction times and reaction temperatures on loading percentage were studied. The details are given in Table 1c below.

    TABLE-US-00003 TABLE 1c Solution-A Fumaric Silica Reaction Reaction Adsorbent Sl KOH acid Water Additive Sol temperature time loading % GSM of No. (g) (g) (mL) (g) (mL) ( C.) (min) on substrate Substrate:Adsorbent adsorbent 1 100 99 450 1 30 45 15 108 43:57 45 2 100 99 450 1.5 30 45 15 126 44:56 43 3 100 99 450 2 30 45 15 132 41:59 45 4 120 99 450 2 30 70 30 115 46:54 39.2 5 120 99 450 2 30 40 60 165 38:62 56 6 120 99 450 2 30 80 45 111 47:53 38 7 120 99 450 2 30 75 60 98 50:50 33

    Example 1d: Using Potassium Hydroxide with Polyvinyl Alcohol and Additive

    [0122] 6 parts of Solution A were prepared using the protocol of Example 1c except that polyvinyl alcohol is added instead of silica sol under mixing. The amounts of potassium hydroxide, xanthan gum additive, and polyvinyl alcohol are varied. Solution Bis prepared as in Example 1b. The substrate comprises of basis weight 33GSM. The procedure of Example 1c is followed for treatment of substrate with Solution A and Solution B, except that the reaction temperatures and times are varied. The loading percentage of MOF synthesized in situ on substrate and effect of varying reactant amounts, reaction temperatures and reaction times on loading percentage as well as on adsorption percentage at 50% RH is studied. The adsorption percentage studies are done on a Belsorp Aqua 3. Process details are in Table 1d below. Sample 3 in Table 1d below was cross-verified by XRD with characteristics peaks at 20 position 10.410, 14.750, 18.270, 20.810, and 26.570, which confirmed the formation of in situ aluminium fumarate. The XRD is shown in FIG. 4a.

    TABLE-US-00004 TABLE 1d Solution-A Fumaric PVA (mL)- Reaction Reaction Adsorbent % water Sl KOH acid Water Additive 10% temperatre time loading % GSM of adsorption No. (g) (g) (mL) (g) solution ( C.) (min) on substrate Substrate:Adsorbent adsorbent at RH-50 1 100 99 450 1 30 45 15 131 54:46 45 32.82 2 100 99 450 1.5 20 45 15 136 42:58 46 31.5 3 120 99 450 2 30 70 30 115 46:54 39.2 32 4 120 99 450 2 30 80 30 80 55:45 27 33.1 5 120 99 450 2 30 40 60 115 46:54 39 30 6 120 99 450 2 30 75 60 92 52:48 31 30.2

    B: Using Pretreated Substrate

    Example 1e. Using Sodium Hydroxide and without Additive

    [0123] Solution A is prepared in 5 parts at ambient temperature by dissolving sodium hydroxide in water. Fumaric acid is then added to it with continuous stirring to get a solution of sodium fumarate. A substrate is pre-treated with 5% silica sol and dried naturally, and divided into 5 equal parts. Each pre-treated substrate part is soaked in a respective part of Solution A at room temperature and then dried naturally. Solution-B is prepared as 5 parts by dissolving aluminium sulphate in water at ambient temperature. Each of the 5 pre-treated substrate parts already dipped or soaked in Solution A are then dipped/soaked in a separate part of solution B respectively for a given a temperature but different times to obtain different amounts of in situ synthesis of aluminium fumarate onto and within the substrate, followed by natural drying. The substrates are then washed with water to remove any by-products formed during the reaction, subjected to natural drying, followed by activation in a drying chamber. Each part of Solution A comprised 25.2 gms of NaOH dissolved in 200 ml of water to which the amount of fumaric acid added was 24.3 gms. The basis weight of the substrate was 33 GSM. Solution B comprised 100 gms of Aluminium sulphate dissolved in 500 ml of water. The reaction temperature was 80 C. The effect of reaction time on loading percentage (in situ synthesized MOF on substrate) was studied. The results obtained are given in Table 1e below.

    TABLE-US-00005 TABLE 1e Reaction Loading % Sl time Substrate:ad- of adsorbent GSM of No. (min) sorbent on substrate adsorbent 1 30 61:39 64.9 21.66 2 60 58:42 71.4 23.82 3 90 41:59 143.2 48.78 4 120 41:59 143.6 48.92 5 150 41:59 145.4 49.54

    Example 1f. Using Sodium Hydroxide, with Additive

    [0124] The procedure as set out in Example 1e was followed except that during preparation of Solution A, 0.5 gms of xanthan gum is also added after the addition of fumaric acid under stirring, followed by further stirring. The basis weight of the substrate was 33 GSM. The effect of additive on reaction time, reaction temperature and loading percentage (of in situ synthesized MOF on substrate) was studied. The results obtained are set out in Table 1f below.

    TABLE-US-00006 TABLE 1f Reaction Reaction Loading % Sl temperature time Substrate:ad- of adsorbent GSM of No. ( C.) (min) sorbent on substrate adsorbent 1 40 15 54:46 85.14 29.34 2 40 30 45:55 120 41.36 3 40 60 45:54 116 40.08 4 80 15 35:65 182 62.74 5 80 30 37:63 169 58.12

    Example 1g. Using Potassium Hydroxide with Additive

    [0125] The procedure set out in Example 1f is followed except that in the preparation of Solution A, instead of sodium hydroxide, 120 gms of potassium hydroxide is used in 450 ml of water with 99 gms of fumaric acid. The amount of xanthan gum additive is 2 gms. The basis weight of the substrate is 33 GSM. Effect of varying reaction temperature on loading percentage of in situ synthesized MOF on the substrate is studied. The results are in Table 1g below:

    TABLE-US-00007 TABLE 1g Sl Reaction Reaction Substrate: Loading % of adsorbent GSM of No. temperature ( C.) time (min) adsorbent on substrate adsorbent 1 80 15 28:72 251.9 100.5 2 90 15 30:70 231.1 92.2 3 110 15 37:63 167.4 66.8

    Example 1h: Using Sodium Hydroxide, Polyvinyl Alcohol, with Additive

    [0126] The procedure set out in Example 1e is followed except that following the addition of fumaric acid, 0.5 gms of xanthan gum additive is also added, followed by further stirring. Thereafter, 10 ml of a 10% solution of polyvinyl alcohol is also added to the resulting solution and mixed well. Solution B comprises 100 gms of Aluminium sulphate in 200 ml of water. The basis weight of the substrate is 33 GSM. The effect of different reaction temperatures and reaction times on loading percentage of in situ synthesized MOF in substrate is studied, and the results are given in Table 1h below.

    TABLE-US-00008 TABLE 1h Reaction Reaction Loading % Water Sl temperature time of adsorbent GSM of adsorption % No. ( C.) (min) Substrate:adsorbent on substrate adsorbent at RH-50 1 40 15 42:58 138.5 46.68 26.7 2 40 30 45:55 122.5 41.3 28.5 3 40 60 47:53 113.6 38.28 25.6 4 80 15 53:47 89.8 30.28 27.7 5 80 30 57:43 74.2 25.02 25.7 6 80 60 67:33 49.3 16.62 19.3

    [0127] In all the above examples, the loading of the in situ synthesized aluminium fumarate onto and within the substrate is measured by taking the differential in actual weight between the bare substrate and the loaded substrate and dividing the result by the bare weight of the substrate. It is found to be in the range between 0.1 to 6 the weight of the bare substrate.

    Example 2: In Situ Synthesis of MIL-100 (Fe)

    A: Using Untreated Substrate

    Example 2a: Using Sodium Hydroxide+with Additive+Ferric Chloride

    [0128] 6 parts of Solution A was prepared by dissolving different quantities of 1,3,5,-benzenetri carboxylic acid in a solution of 10 gms of sodium hydroxide in 250 ml of water, followed by adding differing amounts of xanthan gum as additive under stirring. Solution B is prepared by dissolving 30 gms of ferric chloride in 500 ml of water. The substrate comprising basis weight of 33 GSM is prepared as 6 parts. Each part is dipped in a respective part of Solution A, followed by natural drying, followed by dipping in Solution B to initiate reaction. The reaction temperatures and times are varied. This is followed by washing, natural drying and activation in a drying chamber. Loading percentage of synthesized MOF on substrate, and effect of temperature and time variation on loading percentage are studied. The results are in Table 2a below.

    TABLE-US-00009 TABLE 2a Solution-A 1,3,5 Reaction Reaction Adsorbent Sl NaOH BTC Water Additive temperature time loading % GSM of No. (g) (g) (mL) (g) ( C.) (Hrs) on substrate Substrate:Adsorbent adsorbent 1 10 10.4 250 0.75 80 0.5 118 46:54 49 2 10 10.4 250 0.75 90 6 84 54:46 29 3 10 10.4 250 0.75 90 8 315 24:76 107 4 10 10.4 250 0.75 90 10 338 23:77 115 5 10 13 250 1 RT* 8 79 56:44 27 6 10 13 250 1 RT* 12 71 58:42 24 *RT = room temperature

    Example 2b: Using Sodium Hydroxide+with Additive+Ferric Nitrate

    [0129] The procedure of Example 2a was followed except that Solution A is prepared by dissolving 13 gms of 1,3,5-Benzene tricarboxylic acid in aqueous basic medium of 10 gms of sodium hydroxide in 250 ml of water, followed by addition of 1 gm of xanthan gum under continuous stirring and solution B is prepared by dissolving 30 gms of ferric nitrate in 500 ml of water. The substrate has a basis weight of 33 GSM. The dipping and reaction protocol are as set out in Example 2a. The reaction temperature is kept at 95-C while the reaction time is varied.

    [0130] The effect of varying reaction times on loading percentage of in situ synthesized MOF on substrate is studied. The results are given in Table 2b below.

    TABLE-US-00010 TABLE 2b Sl Reaction time Adsorbent loading % Substrate: GSM of No. (Hrs) on substrate Adsorbent adsorbent 1 6 243 29:71 82 2 8 240 29:71 82 3 10 231 30:70 78

    Example 2c: Using Sodium Hydroxide+with Additive+Polyvinyl Alcohol+Ferric Chloride

    [0131] The protocol of Example 2a is followed except that Solution A is prepared by dissolving 10.4 gms of 1,3,5-Benzene tricarboxylic acid in aqueous basic medium of 10 gms of sodium hydroxide in 250 ml water, followed by addition of 0.75 gms of xanthan gum with continuous stirring followed thereafter by addition of 10 ml of polyvinyl alcohol. Solution-B is prepared by dissolving 30 gms of ferric chloride in 500 ml of water. The protocol of dipping of substrate (having 33 GSM) in Solution A and B is the same as in Example 2a. the reaction temperatures and reaction times are varied. The effect of varying reaction times and temperatures on loading of in situ synthesized MOF on substrate is studied. The process details are in Table 2c below.

    TABLE-US-00011 TABLE 2c Sl Reaction Reaction Adsorbent loading % Substrate: GSM of No. temperature ( C.) time (Hrs) on substrate Adsorbent adsorbent 1 80 0-.5 135 43:57 56 2 90 8 187 34:66 64

    Example 2d: Using Sodium Hydroxide+with Additive+Polyvinyl Alcohol+Ferric Nitrate

    [0132] The procedure, reactants are identical as in Example 2c, except that Solution B is prepared by dissolving 30 gms of ferric nitrate in 500 ml of water. The reaction temperature is 90-C and the reaction times are varied. The results are given in Table 2d below.

    TABLE-US-00012 TABLE 2d Sl Reaction time Adsorbent loading % Substrate: GSM of No. (Hrs) on substrate Adsorbent adsorbent 1 10 188 35:65 64 2 12 129 44:56 44

    Example 2e: Using Ethanol as Solvent+with Additive+Ferric Nitrate

    [0133] The procedure of Example 2a was followed with Solution A being prepared by dissolving 12 gms of 1,3,5-Benzene tricarboxylic acid in a mixture of ethanol-water in a ratio of 1:1 (100 ml each) followed by addition of 0.5 gms of hydroxypropyl methyl cellulose additive under continuous stirring. Solution B is prepared by dissolving 30 gms of ferric nitrate in 500 ml of water. The substrate is of basis weight 33 GSM. Reaction temperature is kept at 90-C while reaction time is varied. The effect of varying reaction time on loading percentage of in situ synthesized MOF on substrate was studied. The results are given in Table 2e below.

    TABLE-US-00013 TABLE 2e Sl Reaction time Adsorbent loading % Substrate: GSM of No. (Hrs) on substrate Adsorbent adsorbent 1 6 87 54:46 29 2 8 242 29:71 82 3 10 232 30:70 79

    B: Using Pre-Treated Substrate

    Example 2f: Using Ferric Chloride, without Additive

    [0134] Three parts of a first solution (Solution-A) are prepared each by dissolving 10.4 gms of 1,3,5-Benzenetricarboxylic acid in aqueous basic medium of 10 gms of sodium hydroxide in 250 ml of water. A substrate comprising of glass fiber and having a basis weight of 33 GSM is pre-treated with 5% silica sol and subjected to natural drying. This pre-treated substrate is also divided into three equal parts. Each pre-treated substrate material after drying is dipped/soaked in a respective part of Solution A at room temperature and then subjected to natural drying. Three parts of a second solution (Solution B) are prepared, each by dissolving 30 gms ferric chloride in 500 ml of water. Each pre-treated substrate which has been treated with Solution A is then separately reacted with a respective part of Solution B at given temperature and time followed by natural drying. Thereafter, the substrates with in situ synthesised MOF are washed with water to remove any by-products formed during the reaction and subjected to natural drying. One substrate part is then treated with 5% silica sol to increase the strength. The substrate parts are thereafter activated. The amount of loading of in situ synthesized MOF on substrate and the effect of variation in time on loading percentage is studied. The results obtained are given in Table 2f below.

    TABLE-US-00014 TABLE 2f Sl Reaction Reaction Substrate: Loading % of adsorbent GSM of No. temperature ( C.) time (min) adsorbent on substrate adsorbent 1 80 15 59:41 70.22 27.08 2 90 15 54:46 91.20 35.16 3 90 30 52:48 91.30 35.22

    Example 2g: Using Ferrous Chloride without Additive

    [0135] The procedure set out in Example 2f is followed. Two parts of Solution A is prepared each by dissolving 50.25 gms of 1,3,5-benzenetricarboxylic acid in a solution of 27 gms of sodium hydroxide dissolved in 650 ml of water. Two parts of Solution B is prepared where in each part, instead of ferric chloride, 12 gms of ferrous chloride is dissolved in 480 ml of water. The pre-treated substrate is also divided into two equal parts. The substrate comprises 33 GSM basis weight. The loading percentage of MOF synthesized in situ on substrate and the effect of time variation on loading percentage is studied. The results obtained are given in Table 2g below:

    TABLE-US-00015 TABLE 2g Sl Reaction Reaction Substrate: Loading % of adsorbent GSM of No. temperature ( C.) time (hrs) adsorbent on substrate adsorbent 1 RT 12 57:43 75.3 25.6 2 RT 24 61:39 63.82 21.7

    Example 3: In Situ Synthesis of CAU-10H

    [0136] Two parts of Solution A are prepared, each by dissolving 50 gms of Isophthalic acid in 250 ml of dimethyl formamide as solvent. A substrate having basis weight of 33 GSM is pre-treated with 5% silica sol and then dried naturally. This dried substrate is then also divided into two equal parts. Each part is then soaked in a respective part of solution A at room temperature followed by natural drying. Two parts of Solution B are prepared, each by dissolving 100 gms of aluminium sulphate in 500 ml of water. Each part of substrate already dipped in solution A is then separately dipped into respective part of Solution B to initiate a reaction at 70-C at different times, followed by natural drying. The substrate is then washed with water to remove the by-products formed during the reaction, subjected to natural drying and activation in a drying chamber at 140 C. for 2 Hrs. The percentage loading of in situ synthesized MOF on substrate and effect of time variation on loading are studied. The results are in Table 3 below.

    TABLE-US-00016 TABLE 3 Sl Reaction Reaction Substrate: Loading % of adsorbent GSM of No. temperature ( C.) time (min) adsorbent on substrate adsorbent 1 70 15 44:56 125.1 48.2 2 70 30 45:55 123.24 47.52

    Example 4: In Situ Synthesis of COF-1

    [0137] Solution A is prepared by dissolving 2 gms of 1,4-benzene diboronic acid in a mixture of ethanol-water in a ratio of 1:3 by volume. 1.5 gms of xanthan gum is added followed by addition of 10 ml of silica sol with continuous stirring. Solution-B is prepared by mixing mesitylene and 1,4-dioxane in a ratio of 1:1 by volume. The reaction time is 2 hours and the reaction temperature is room temperature. The results are given in Table 4 below. The FTIR peaks corresponding to B-O at 138.1%, B-C at 1026.3%, B3O3 at 710.9% transmittance confirms the formation of COF-1 as shown in FIG. 4b compared with available literature.

    TABLE-US-00017 TABLE 4 Sl No. of Adsorbent loading % Substrate: GSM of No. dippings on substrate Adsorbent adsorbent 1 1 54 64:36 18 2 2 82 55:45 28

    Example 5: In Situ Synthesis of ZIF-1

    [0138] The procedure of Example 4 is followed except that Solution A is prepared by dissolving 6 gms of imidazole in 360 ml of DMF, and Solution B is prepared by dissolving 4.05 gms of zinc nitrate in 405 ml of dimethyl formamide. The reaction time is 30 minutes and reaction temperature is 70-C. The results are in Table 5 below. The representative XRD peaks at 20 position 23.39 corresponds to the maximum relative intensity as reported in literature for ZIF-1. This is shown in FIG. 4c.

    TABLE-US-00018 TABLE 5 Sl Substrate: Loading % of adsorbent GSM of No. adsorbent on substrate adsorbent 1 81:19 23.59 8.02 2 70:30 43.23 14.7

    Example 6: Sequential Dipping in Solution a and Solution Bin any Order

    Example 6a

    [0139] The procedure of Example 1g is followed except that the substrate consisting of glass fibers is not subjected to any pre-treatment, and the sequence of dipping comprises first Solution A followed by Solution B. The results are given in Table 6a below:

    TABLE-US-00019 TABLE 6a Solution-A Fumaric Reaction Reaction Adsorbent % water Sl KOH acid Water Additive temperature time loading % GSM of adsorption No. (g) (g) (mL) (g) ( C.) (min) on substrate Substrate:Adsorbent adsorbent at RH-50 1 120 99 450 2 70 30 104 49:51 33.6 32.3 2 120 99 450 2 70 30 158 38:62 54 30.3

    Example 6b

    [0140] The procedure of Example 6a is followed except that the sequence of dipping comprises Solution B followed by Solution A. The results are given in Table 6b below:

    TABLE-US-00020 TABLE 6b Solution-A Fumaric Reaction Reaction Adsorbent % water Sl KOH acid Water Additive temperature time loading % GSM of adsorption No. (g) (g) (mL) (g) ( C.) (min) on substrate Substrate:Adsorbent adsorbent at RH-50 1 100 99 450 2 50 30 136 42:58 46 29.1 2 120 99 450 2 70 30 144 41:59 49 28.6

    Example 7: Co-Synthesis of Aluminium Fumarate and CAU-10H

    [0141] Solution A1 is prepared by dissolving isophthalic acid in DMF. Solution A2 is prepared by adding potassium hydroxide to water followed by addition of fumaric acid with continuous stirring. Equal amounts of both the above solutions are mixed together to form a uniform Solution A. The glass fiber substrate is soaked in the above solution at room temperature and then kept for natural drying. Solution Bis prepared by dissolving aluminium sulphate in water. The glass fiber substrate, already dipped in Solution A, is then reacted with Solution B at given temperature and time followed by natural drying. The synthesized glass fiber is then washed with water to remove the by-products formed during the reaction. It was then natural dried and activated in a drying chamber at 140 C. for 2 Hrs. The process conditions, concentrations and results are given in Table 7.

    TABLE-US-00021 TABLE 7 Solution-A1 Solution-A2 Isophthalic Fumaric Solution-A Reaction Reaction Loading % Sl acid DMF acid KOH Water (A1 + A2) temperature time of adsorbent GSM of No. (g) (ml) (g) (g) (ml) (ml) ( C.) (min) Substrate:Adsorbent on substrate adsorbent 1 20 100 24.75 30 112.5 200 80 15 65:35 53 17.7 2 20 100 24.75 30 112.5 200 80 30 66:34 52.2 17.4

    Example 8: Co-Synthesis of Aluminium Fumarate and Aluminium Silicate

    [0142] Solution-A is prepared by dissolving potassium hydroxide in water. Fumaric acid is then added to it with continuous stirring. Xanthan gum is added followed by addition of sodium silicate and mixed well. Substrate is soaked in the above solution at room temperature and then kept for natural drying. Solution-B is prepared by dissolving aluminium sulphate in water. The substrate, already dipped in solution-A, is then reacted with solution-B at given temperature and time and then kept for natural drying. The synthesized substrate is washed with water, to remove the by-products formed during the reaction. It is then natural dried and activated in a drying chamber at 140 C. for 2 hours. The details are given in Table 8.

    TABLE-US-00022 TABLE 8 Solution-A Sodium Fumaric Silicate Reaction Reaction Adsorbent Sl KOH acid Water Additive (Sp. Gravity: temperature time loading % GSM of No. (g) (g) (mL) (g) 1.30 (mL) ( C.) (min) on substrate Substrate:Adsorbent adsorbent 1 120 99 450 2 150 45 30 220 31:69 75 2 120 99 450 2 450 45 30 183 35:65 62

    Example 9: Cross Co-Synthesis: Cross Co-Synthesis of Aluminium Fumarate and MIL-100(Fe)

    [0143] Solution-A1 is prepared by dissolving 1,3,5-Benzene tricarboxylic acid in aqueous basic solvent, i.e., sodium hydroxide in water with continuous stirring. Xantham gum is also added as an additive. Solution-A2 is prepared by adding potassium hydroxide to water followed by addition of fumaric acid with continuous stirring. Xantham gum is also added as an additive. Both the above solutions are mixed together to form a uniform solution-A. Solution-B1 is prepared by dissolving Ferrous chloride in water. Solution-B2 is prepared by dissolving aluminium sulphate in water. Equal amounts of both the above solutions are mixed together to form a uniform solution-B. The glass fiber substrate is soaked in the solution-A at room temperature and then kept for natural drying. The glass fiber substrate, already dipped in solution-A, is then reacted with solution-B at given temperature and time followed by natural drying. The synthesized glass fiber is then washed with water, to remove the by-products formed during the reaction. It was then natural dried and activated in a drying chamber at 140 C. for 2 Hrs. The results are given in Table 9 below.

    TABLE-US-00023 TABLE 9 Solution-A1 Solution-A2 1,3,5- Fumaric Sl NaOH BTC acid Water Additive acid KOH Water Additive No. (g) (g) (ml (g) (g) (g) (ml) (g) 1 27.4 50.28 650 0 24.75 30 112.5 0 2 10 10.4 250 0.75 99 120 450 2 Solution-A Reaction Reaction Loading % Sl (A1 + A2) temperature time of adsorbent GSM of No. (ml) ( C.) (min) Sub:ads on substrate adsorbent 1 100 + 100 90 30 81:19 23.4 7.84 2 50 + 150 65 60 65:35 52 17.8

    Example 10: Manufacture of Honeycomb Matrix with In Situ Synthesized Aluminium Fumarate (as Shown in FIG. 8)

    [0144] Solution A is prepared by dissolving 18.1 kg of potassium hydroxide in 68L of water, followed by addition of 15 kg of fumaric acid at a temperature in the range of 60 C. with continuous stirring. A viscosity increasing additive, xanthan gum 300 g, is added with continuous agitation. 5 L of polyvinyl alcohol is also added and mixed well. A glass fiber based substrate, to form a honeycomb geometry, is immersed in the Solution A. The substrate is then corrugated to form a rotor, which is then dipped in aluminium sulphate solution having specific gravity of 1.20. The soak time is 30 minutes and soak temperature is 45 C. The rotor is then dried, washed and again dried, followed by activation in a drying chamber. The results are given in Table 10 below.

    TABLE-US-00024 TABLE 10 Adsorbent loading % Substrate: on substrate Adsorbent 139 42:58

    Example 11: Manufacture of a Honeycomb Rotor Through a Continuous Process of Synthesis of Adsorbent Simultaneous and In Situ of the Substrate Passing Through the Continuously Formed Mixture of Component A and B Whereafter it is Formed into a Honeycomb Substrate. (Shown in FIG. 9)

    [0145] Solution A is prepared by dissolving 6.33 kg of sodium hydroxide in 53.75 L of water, followed by addition of 6.08 kg of fumaric acid at room temperature with continuous stirring. Solution B is prepared by dissolving 12.5 kg of aluminium sulphate in 50 L of water. Both the solutions are mixed together at a temperature of 35 C. A substrate is continuously passed from this solution and converted into a honeycomb shape to form a rotor. The rotor is then dried, washed and again dried, followed by activation in a drying chamber. The results are given in Table 11 below.

    TABLE-US-00025 TABLE 11 Adsorbent loading % Substrate: % water adsorption on substrate Adsorbent at RH-50 73.5 58:42 31.4

    Example 12: Manufacture of a Preformed Honeycomb Matrix Having a MOF Synthesized In Situ (onto and within the Porous Substrate of the Honeycomb) According to One Embodiment of the Invention (FIG. 10)

    [0146] A honeycomb matrix is prepared using glass fiber substrate and silica sol as rigidifying agent. Solution A is prepared by dissolving 18.1 kg of potassium hydroxide in 68L of water, followed by addition of 15 kg of fumaric acid at a temperature in the range of 60 C. with continuous stirring. A viscosity increasing additive, xanthan gum 300 g, is added with continuous agitation. 5 L of polyvinyl alcohol is also added and mixed well. Solution-B is aluminium sulphate solution having specific gravity of 1.20. The pre-treated matrix is then dipped in solution-A for 5 minutes at room temperature, which is then natural dried and dipped in solution-B. The soak time is 30 minutes and soak temperature is 45 C. The rotor is then dried, washed and again dried, followed by activation in a drying chamber. Results are in Table 12 below.

    TABLE-US-00026 TABLE 12 Adsorbent loading % Substrate: % water adsorption on substrate Adsorbent at RH-50 80 55:45 31.8

    Example 13: Manufacture of a Honeycomb Matrix Rotor by Impregnating the Substrate in a Slurry of Aluminium Fumarate and Forming into a Honeycomb Rotor (as Shown in FIG. 11)

    [0147] A slurry of aluminium fumarate is prepared by adding 20 kg of aluminium fumarate to 31.6 L of water with continuous agitation. When complete mixing has taken place, 21 L of acidic sol with specific gravity of 1.12 is added to it. 20 L of polyvinyl alcohol is then added to the solution and mixed well until a homogeneous solution is obtained. A glass fiber substrate is immersed in this slurry followed by corrugation. The rotor that is formed is dried followed by dipping in 5% silica sol. It is then dried and activated. Results are in Table 13 below.

    TABLE-US-00027 TABLE 13 Adsorbent loading % Substrate: on substrate Adsorbent 280 38:62

    Example 14: A Pre-Prepared Honeycomb Matrix Rotor Impregnated by Dipping in a Slurry of Aluminium Fumarate (as Shown in FIG. 12)

    [0148] A slurry containing aluminium fumarate is prepared by adding 20 kg of aluminium fumarate to 31.6 L of water with continuous agitation. When complete mixing has taken place, 21 L of acidic sol with specific gravity of 1.12 is added to it. 20 L of polyvinyl alcohol is then added to the solution and mixed well until a homogeneous solution is obtained. A honeycomb matrix is prepared using glass fiber substrate and silica sol as rigidifying agent. This matrix is then dipped in the slurry. The rotor formed is dried followed by activation in a drying chamber. Results are in Table 14 below.

    TABLE-US-00028 TABLE 14 Adsorbent loading % Substrate: % water adsorption on substrate Adsorbent at RH-50 82 56:44 34.2