AMORPHOUS METAL ORGANIC FRAMEWORKS AND METHODS OF PREPARING THE SAME

Abstract

The present disclosure relates to amorphous metal organic frameworks with high and/or selective molecular uptake, absorbent materials comprising the same, methods for preparing the same and the use of the same for uptaking/absorbing fluids.

Claims

1. (canceled)

2. An amorphous metal organic framework, comprising: (i) a metal cluster; and (ii) one or more ligands having two or more carboxylate groups; wherein the metal cluster comprises iron.

3. (canceled)

4. An amorphous metal organic framework according to claim 2, wherein the metal cluster has the formula Fe.sub.2XO, and X is metal selected from Group 2 through Group 16; optionally wherein X is selected from Al, Fe, Co, Mn, Zn, Ni, Mg, Cu, and Ca.

5. (canceled)

6. An amorphous metal organic framework according to claim 2, wherein the metal cluster has the formula Fe.sub.3O.

7. (canceled)

8. (canceled)

9. (canceled)

10. An amorphous metal organic framework according to claim 2, wherein the one or more ligands is derived from ABTC: ##STR00049##

11. An absorbent material comprising a porous substrate impregnated with a metal organic framework; wherein the metal organic framework is an amorphous iron, aluminium, or titanium metal organic framework.

12. (canceled)

13. (canceled)

14. An absorbent material according to claim 11, comprising (i) a metal cluster; and (ii) one or more ligands having two or more carboxylate groups; or comprising (i) a metal node; and (ii) one or more ligands having two or more carboxylate groups.

15. (canceled)

16. An absorbent material according to claim 14; wherein the metal cluster/node comprises a metal selected from iron, aluminium, titanium, chromium and zirconium; optionally wherein the metal cluster/node has the formula Fe.sub.3O; Al.sub.3O; TiO, Ti.sub.8O.sub.8 or Ti.sub.16O.sub.16.

17. (canceled)

18. (canceled)

19. (canceled)

20. An absorbent material according to claim 14, wherein the ligand is derived from ABTC: ##STR00050##

21. An absorbent material according to claim 11, wherein the absorbent material has BET surface area between about 100 and about 1200 m.sup.2g.sup.−1, or about 200 and about 1100 m.sup.2g.sup.−1, or about 200 and about 900 m.sup.2g.sup.−1, or about 200 and about 800 m.sup.2g.sup.−1, or about 300 and about 800 m.sup.2g.sup.−1, or about 400 and about 800 m.sup.2g.sup.−1.

22. An absorbent material according to claim 11, wherein the porous substrate comprises pores having a pore diameter of from about 2.0 nm to about 50 nm; and/or wherein the porous substrate is microporous or mesoporous; and/or wherein the porous substrate is selected from activated carbon, silica, and silica gel; and/or wherein the porous substrate does not contain crystalline metal organic framework.

23. (canceled)

24. (canceled)

25. (canceled)

26. An absorbent material according to claim 11, wherein at least a portion of the amorphous metal organic framework is impregnated in the porous substrate; optionally further comprising crystalline or polycrystalline metal organic framework, the metal organic framework being at least 75% amorphous.

27. (canceled)

28. (canceled)

29. (canceled)

30. (canceled)

31. (canceled)

32. (canceled)

33. (canceled)

34. (canceled)

35. (canceled)

36. (canceled)

37. (canceled)

38. (canceled)

39. A process of preparing an amorphous metal organic framework as defined in claim 2, comprising the steps of contacting a reaction mixture comprising a metal source, a ligand precursor, a solvent and optionally an acid with a porous substrate; and subsequently removing the liquid component from the substrate.

40. (canceled)

41. A process according to claim 39, wherein the acid is selected from trifluoroacetic acid, benzoic acid, formic acid, propionic acid, sodium acetate, and acetic acid.

42. A process according to claim 39, wherein the reaction mixture further comprises dissolved metal organic framework.

43. A process according to claim 39, wherein the reaction mixture further comprises acetic acid and/or methanol.

44. A process according to claim 39, wherein the reaction mixture is virgin synthesis fluid or is recovered fluid from a process of preparing crystalline metal organic framework.

45. A process according to claim 39, wherein the substrate is soaked in the reaction mixture, wherein the substrate is soaked for a sufficient time to allow for the reaction mixture to permeate the substrate.

46. A process according to claim 39, wherein the liquid component is removed from the substrate after adequate soaking such that amorphous metal organic framework is formed during the soaking process and/or through the removal process.

47. A process according to claim 46, wherein removing the liquid component is carried out by extracting the fluid component using heat, pressure/vacuum or a combination of heat and pressure/vacuum.

48. A process according to claim 47, wherein the extraction of the liquid component is controlled by regulating the heat and/or pressure/vacuum to deliberately remove the individual components of the liquid component, to deliberately remove the liquid component in bulk, or to deliberately remove groups of components together.

49. (canceled)

50. (canceled)

53. (canceled)

54. (canceled)

Description

[0348] The disclosure will now be described further with reference to the following non-limiting examples and the accompanying Figures, in which:

[0349] FIG. 1 illustrates the differences between amorphous, polycrystalline, and monocrystalline materials.

[0350] FIG. 2. Visual examples of monocrystalline PCN-250Fe through SEM imaging.

[0351] FIG. 3A. XRD comparing crystalline PCN-250Al against activated carbon with amorphous PCN-250Al (metal organic framework of Al and ABTC).

[0352] FIG. 3B. BET comparing activated carbon against activated carbon with amorphous PCN-250Al (metal organic framework of Al and ABTC).

[0353] FIG. 3B Supplemental. Expanded view of FIG. 3B.

[0354] FIG. 3C. Free volume hole size distribution comparing activated carbon (peak at approx. 7 {acute over (Å)}) against activated carbon with amorphous PCN-250Al (metal organic framework of Al and ABTC).

[0355] FIG. 3C Supplemental. Illustrated version of FIG. 3C.

[0356] FIG. 4A. XRD comparing crystalline PCN-250Al against silica with amorphous PCN-250Al (metal organic framework of Al and ABTC).

[0357] FIG. 4B. BET comparing silica (bottom lines) against silica with amorphous PCN-250Al (metal organic framework of Al and ABTC).

[0358] FIG. 4B Supplemental. Expanded view of FIG. 4B.

[0359] FIG. 4C. Free volume hole size distribution comparing silica (top line) against silica with amorphous PCN-250Al (metal organic framework of Al and ABTC).

[0360] FIG. 4C Supplemental. Expanded view of FIG. 4C.

[0361] FIG. 5A. XRD comparing crystalline PCN-250Fe against silica gel with amorphous PCN-250Fe (metal organic framework of Fe and ABTC).

[0362] FIG. 5B. BET comparing silica gel against silica gel with amorphous metal organic framework of Fe and ABTC.

[0363] FIG. 5B Supplemental. Expanded view of FIG. 5B. The silica gel is the bottom line. Silica gel with amorphous PCN250Fe is the top line.

[0364] FIG. 5C. Free volume hole size distribution comparing silica gel (lower peak) against silica gel with amorphous PCN-250Fe (metal organic framework of Fe and ABTC).

[0365] FIG. 5D. Water adsorption graph comparing silica gel against silica gel with amorphous PCN250Fe (metal organic framework of Fe and ABTC).

[0366] FIG. 5E. Expanded view of FIG. 5D with different x-axis and overlay of uptake increase. The silica gel is the bottom line. The silica gel with amorphous PCN-250Fe is the top line.

[0367] FIG. 5F: Volumetric methane adsorption graph comparing silica gel (squares) against silica gel with amorphous PCN-250Fe (metal organic framework of Fe and ABTC) (circles).

[0368] FIG. 5G: Gravimetric comparison of methane adsorption and a mixture of 1 mol % hydrogen sulfide in methane, comparing silica gel with silica gel with amorphous PCN-250Fe (metal organic framework of Fe and ABTC).

[0369] FIG. 6A. XRD comparing crystalline PCN-250Fe against activated carbon with amorphous PCN-250Fe (metal organic framework of Fe and ABTC).

[0370] FIG. 6B. BET comparing activated carbon (bottom lines) with activated carbon with amorphous PCN-250Fe (metal organic framework of Fe and ABTC).

[0371] FIG. 6B Supplemental. Expanded view of FIG. 7B. Activated carbon is the bottom lines. Activated carbon with amorphous PCN-250Fe is the top lines.

[0372] FIG. 6C. Free volume hole size distribution of activated carbon (higher peak) and activated carbon with amorphous PCN-250Fe (metal organic framework of Fe and ABTC).

[0373] FIG. 6C Supplemental. Illustrated view of FIG. 6C.

[0374] FIG. 7A. SEM of activated carbon with amorphousPCN-250Al (metal organic framework of Al and ABTC).

[0375] FIG. 7B. EDX and SEI showing concentrations of aluminium in activated carbon (control).

[0376] FIG. 7C. EDX and SEI showing concentrations of aluminium in activated carbon with amorphous PCN-250Al (metal organic framework of Al and ABTC).

[0377] FIG. 7D. Elemental analysis for aluminium in activated carbon.

[0378] FIG. 7E. Elemental analysis for aluminium in activated carbon with amorphous PCN-250Al (metal organic framework of Al and ABTC).

[0379] FIG. 8A. SEM of silica with amorphous PCN-250Al (metal organic framework of Al and ABTC).

[0380] FIG. 8B. EDX and SEI showing concentrations of aluminium in silica (control).

[0381] FIG. 8C. EDX and SEI showing concentrations of aluminium in silica with amorphous PCN-250Al (metal organic framework of Al and ABTC).

[0382] FIG. 9: XRD comparing crystalline metal organic framework of Ti and 2-amino-BDC (Ti.sub.8O.sub.8(OH).sub.4(2-amino-BDC).sub.6)-labelled MIL-125 NH2 (Ti) showing multiple peaks-against silica gel with amorphous metal organic framework of Ti and 2-amino-BDC (Ti.sub.8O.sub.8(OH).sub.4(2-amino-BDC).sub.6)-labelled Silica gel with aMIL-125-NH2(Ti) showing no peaks.

[0383] FIG. 10: XRD comparing crystalline metal organic framework of Ti and H2BDC (Ti.sub.8O.sub.8(OH).sub.4(BDC).sub.6)-labelled MIL-125 (Ti) showing multiple peaks-against silica gel with amorphous metal organic framework of Ti and H2BDC (Ti.sub.8O.sub.8(OH).sub.4(BDC).sub.6)-labelled Silica gel with MIL-125-NH2(Ti) showing no peaks.

[0384] FIG. 11A: XRD comparing crystalline PCN-250Fe (showing multiple peaks) against activated carbon with amorphous PCN-250Fe (metal organic framework of Fe and ABTC) showing no peaks.

[0385] FIG. 11B: BET comparing activated carbon (showing greater adsorption above approx. 0.30) against activated carbon with amorphous PCN-250Fe (metal organic framework of Fe and ABTC).

[0386] FIG. 11C: Free volume hole size distribution of activated carbon (showing single peak) against activated carbon with amorphous PCN-250Fe (metal organic framework of Fe and ABTC).

EXAMPLES

[0387] Testing

[0388] Adsorption/Desorption Measurements:

[0389] The amount of gas adsorbed, n.sup.a, by the mass, m.sup.s, of solid is dependent on the equilibrium pressure, p, the temperature, T, and the nature of the gas-solid system. Thus, we may write:

n.sup.a/m.sup.s=f(p,T,system)  (equation 1)

[0390] For a given gas adsorbed on a particular solid at constant temperature we have

n.sup.a/m.sup.s=f(p).sub.T  (equation 2)

[0391] and if the gas is below its critical temperature, it is possible to write

n.sup.a/m.sup.s=f(p/p.sup.o).sub.T  (equation 3)

[0392] where here, the standard pressure p.sup.o is equal to the saturation pressure of the adsorptive at T.

[0393] Equations (2) and (3) represent the adsorption isotherm which is the relationship between the amount adsorbed by unit mass of solid and the equilibrium pressure (or relative pressure), at a known temperature (Rouquerol, Franqoise. Adsorption by Powders and Porous Solids: Principles, Methodology and Applications. Elsevier, Academic Press, 2014).

[0394] The experimental adsorption isotherm is usually presented in graphical form. Here, for all samples, nitrogen gas (N.sub.2) sorption measurements were conducted using a Micromeritics ASAP 2020 and 2420 system. The sample weights were measured using an analytical balance and loaded into the Micromeritics ASAP 2020 and 2420 system. At the end of the N.sub.2 sorption measurements, the data of the amount adsorbed N.sub.2 by unit mass of tested sample was generated by the measurement system. In addition, the ASAP 2020 AND 2420 system software was used to gather the required surface area and porosity information for reporting (ASAP 2020 Accelerated Surface Area and Porosimetry System Brochure, Micromeritics Instrument Corporation 4356 Communications Drive Norcross, Ga. 30093 USA http://www.micromeritics.com/Repository/Files/ASAP_2020_Brochure_3.pdf) [0395] Single- and Multipoint BET (Brunauer, Emmett, and Teller) surface area [0396] Langmuir surface area [0397] Temkin and Freundlich isotherm analyses [0398] Pore volume and pore area distributions in the mesopore and macropore ranges by the BJH (Barrett, Joyner, and Halenda) method using a variety of thickness equations [0399] Pore volume and total pore volume in a user-defined pore size range [0400] Micropore distribution by the MP method and total micropore volume by the t-Plot and as Plot methods [0401] Pore width/diameter

[0402] The reported data which included N.sub.2 sorption measurements, pore volume and pore area distributions (including micropore distribution), were graphed using the graphics module of the instrument software. Graphs with user-defined ranges (relative pressure and pore size) were generated using MS Excel based on the (N.sub.2) sorption measurements.

[0403] The N.sub.2 sorption measurements were conducted at 77 K.

[0404] The same equipment was used to obtain water adsorption measurements and so water adsorption isotherm graphs were plotted accordingly.

[0405] The water sorption measurements were conducted at 25° C.

[0406] Volumetric Uptake Tests:

[0407] Volumetric methane uptake tests were conducted by loading approximately 0.4 g of the of each adsorbent, silica gel and silica gel with aPCN-250 Fe, into a tared 2 mL stainless steel sample holder inside a glovebox under an Ar atmosphere. The sample holder was weighed to determine the sample mass prior to connecting to the VCR fittings of the complete high-pressure assembly while still inside the glovebox. The fully assembled sample holder was then transferred to an ASAP 2020 low-pressure adsorption instrument and evacuated using the original activation temperature for the material. The sample holder was then transferred to the High pressure volumetric analyzer (HPVA II) from Particulate Systems-Micromeritics, connected to the analysis port of the instrument via an OCR fitting, and evacuated at room temperature for at least 45 minutes. The sample holder was placed inside an aluminum Dewar. The sample volume is determined by subtracting the total free space of the filled sample holder from that of the empty sample holder. Excess gravimetric uptake data g/v (g/cm3) measured by the HPVA II is volumetrically calculated based on: A) the absorbent density, B) total pore volume of the absorbent, and C) the bulk gas density at each temperature and pressure.

[0408] Gravimetric Uptake Tests:

[0409] Gravimetric methane and hydrogen sulfide dosed methane tests were conducted by adding approximately 0.7 grams of silica gel or silica gel with aPCN-250 Fe to 1.45 mL Swagelok stainless steel tube testing cells. Each testing cell was placed in an oven at 150° C. for one hour for activation. Each testing cell was vacuum purged for 3 minutes and then nitrogen purged at 50 psig. 150 mL Swagelok sample cylinders were filled with each testing gas (methane or a mixture of 1 mol % hydrogen sulfide and 99% methane) at 100 psig from a Praxair pressurized gas cylinder. The testing gas was then directed from each sample cylinder to the respective testing cell for one hour. After exposure, gas uptake was measured by weighing the testing cell with silica gel or silica gel with aPCN-250 Fe relative to the testing cell with silica gel or silica gel with aPCN-250 Fe and the accumulated testing gas with a Mettler AE200 analytical balance.

[0410] Powder X-ray Diffraction:

[0411] Powder X-ray diffraction (PXRD) was carried out with a Bruker D8-Focus Bragg-Brentano X-ray Powder Diffractometer equipped with a Cu sealed tube (λ=1.54178 A°) at 40 kV and 40 mA.

[0412] SEM/SEI/EDS Imagery:

[0413] Scanning Electron Microscopy (SEM) measurements were carried out on JEOL JSM-7500F. JEOL JSM-7500F is an ultra-high-resolution field emission scanning electron microscope (FE-SEM) equipped with a high brightness conical FE gun and a low aberration conical objective lens. For EDS and SEI imagery, following accessories of the JSM-7500 were used: conventional in-chamber Everhart-Thornley and through-the-lens secondary detectors, low angle back-scattered electron detector (LABE), IR-CCD chamber camera, Oxford EDS system equipped with X-ray mapping and digital imaging.

Example 1. Activated Carbon with Amorphous Metal Organic Framework of Al and ABTC

[0414] A mixture of DMF (120 mL) and acetic acid (60 mL) were combined with 1.8 g of ABTC (azobenzene-tetracarboxylic acid) as well as 3.2 g of aluminium chloride. The mixture was heated at 150° C. 1.8 g of activated carbon untreated was added to the mixture once uniform. The combined mixture was placed in a 150° C. oven for two hours. The solid cylindrical activated carbon was filtered and then washed using methanol. The resulting amorphous metal organic framework was placed in a vacuum oven for 1 hour for further drying.

[0415] XRD spectra of the crystalline metal organic framework PCN-250Al and activated carbon comprising the amorphous metal organic framework of example 1 were plotted.

[0416] N.sub.2 adsorption/desorption isotherms and free volume hole size distribution graphs of activated carbon and activated carbon comprising the amorphous metal organic framework of example 1 were plotted.

[0417] As shown in FIG. 3A, the synthesis of example 4 results in the formation of amorphous metal organic framework of aluminium and ABTC. In FIG. 3A, the top line (labelled PCN-250Al) represents the XRD spectrum of the crystalline metal organic framework PCN-250Al. The Bragg's peaks that are characteristic of this crystalline metal organic framework are clearly visible. In FIG. 3A, the bottom line (labelled Activated Carbon with aPCN-250Al) represents the XRD spectrum of the product of example 1. This spectrum contains no Bragg's peaks and as such confirms the amorphous nature of the metal organic framework of example 1.

[0418] The BET surface area for activated carbon was calculated as 868.4 m.sup.2g.sup.−1. The BET surface area for activated carbon comprising the amorphous metal organic framework of example 1 was calculated as 884.48 m.sup.2g.sup.−1. The increase in surface area attributed to the formation of the amorphous metal organic framework of example 1 is therefore 16.08 m.sup.2g.sup.−1 (an increase of 1.9%).

[0419] FIG. 3B shows the full N.sub.2 absorption/desorption isotherms for activated carbon and activated carbon comprising the amorphous metal organic framework of example 1. It is clear that the total quantity of N.sub.2 that is adsorbed by activated carbon comprising the amorphous metal organic framework of example 1 is significantly greater than the total quantity of N.sub.2 adsorbed by activated carbon without the amorphous metal organic framework of example 1. The increase in N.sub.2 adsorption is predominantly due to the increase in surface area provided by the amorphous metal organic frame work of example 1.

[0420] Not only does activated carbon comprising the amorphous metal organic framework of example 1 absorb a greater quantity of N.sub.2, the increase in adsorption is in the most commercially relevant region, i.e. the low pressure region. In particular, activated carbon comprising the amorphous metal organic framework of example 1 begins to outperform clean activated carbon as low as approximately 0.17 p/p.sup.o. There is a need to provide materials that adsorb fluids at low partial pressures as this leads to reduced industrial set-up and operating costs.

[0421] FIG. 3B supplemental is an expanded view of FIG. 3B wherein the relative pressure has been limited to the 0-0.5 p/p.sup.o range. In FIG. 3B supplemental the absorption isotherms have been split into two sections: from 0-0.1 p/p.sup.o (region A) and from 0.1-0.42 p/p.sup.o(region B). In region A there is no increase in adsorption of activated carbon comprising the amorphous metal organic framework of example 1 relative to activated carbon. The increase in BET surface area and adsorption therefore originates in region B.

[0422] Region A is generally associated with the filling of micropores. The filling of micropores can be split into two groups: primary filling (the filling of micropores with a width of less than 10 Å), and secondary filling (the filling of micropores with a width of between 10 Å and 20 Å). Primary filling is affected by the formation of new micropores or the blocking of existing micropores. Secondary filling is affected by the formation of new micropores, the blocking of existing micropores and the modification of existing micropores (amorphous metal organic framework formation leading to surface irregularities on the internal surfaces of the pores).

[0423] FIG. 3C demonstrates that primary filling decreases and that secondary filling increases for activated carbon comprising the amorphous metal organic framework of example 1. Furthermore, there is an increase in adsorption in the mesoporous range attributable to enhanced multilayer formation (see FIG. 3C supplemental). The decrease in adsorption associated with primary filling is therefore compensated by the increase in secondary filling.

[0424] However, the increase in BET surface area is not entirely attributable to new micropore formation. There is also an increase in the adsorption in mesopores. This adsorption is demonstrated by the relative increase in adsorption in region B and is due to the formation of the amorphous metal organic framework of example 1 on the internal surfaces of the mesopores which leads to enhanced multilayer formation. Multilayer formation is the formation of multiple layers of adsorbate on the internal surfaces of the mesopores and is affected by the surface irregularities provided by the formation of the amorphous metal organic framework of example 1 on the internal surfaces of the mesopores.

[0425] Activated carbon comprising the amorphous metal organic framework of example 4 therefore exhibits increased low pressure adsorption, increased total adsorption and increased BET surface area relative to clean activated carbon. Importantly, the adsorption ability has been increased in pores with a width of 10-30 Å and at low pressures. This results in increased small molecule adsorption.

[0426] The SEM image in FIG. 7A shows activated carbon with amorphous metal organic framework of aluminium and ABTC. There are no crystalline regions observed.

[0427] The EDX image on the left hand side of FIG. 7B shows a low concertation aluminium (aluminium is represented by the white dots on the black background) in clean activated carbon. The right hand side of FIG. 7B is an SEI image of clean activated carbon and shows no crystalline regions.

[0428] In contrast to the EDX image on the left hand side of FIG. 7B, the EDX image on the left hand side of FIG. 7C shows a higher concertation aluminium (aluminium is represented by the white dots on the black background) in activated carbon comprising amorphous metal organic framework of aluminium and ABTC. The right hand side of FIG. 7C is an SEI image of activated carbon comprising amorphous metal organic framework of aluminium and ABTC and shows no crystalline regions. The areas circled (1, 2, 3, and 4) highlight where an increase of aluminium is in the activated carbon showing that the amorphous metal organic framework of aluminium and ABTC has formed in the pores of the activated carbon and further that these metal organic framework regions are amorphous.

[0429] The difference in aluminium peaks in FIG. 7D and FIG. 7E further confirms the increase in aluminium in the activated carbon comprising amorphous metal organic framework of aluminium and ABTC.

Example 2. Silica with Amorphous Metal Organic Framework of Al and ABTC

[0430] A mixture of DMF (120 mL), and acetic acid (60 mL) were combined with 1.8 g of ABTC (azobenzene-tetracarboxylic acid) as well as 3.2 g of aluminium chloride. The mixture was heated at 150° C. 1.8 g of amorphous silica was added to the so mixture once uniform. The combined mixture was placed in a 150° C. oven for two hours to dissolve any powders. Every hour, the mixture was shaken to ensure no clumping of powders. The silica comprising amorphous metal organic framework of aluminium and ABTC was separated under centrifugation and washed twice using methanol, to remove any impurities. The resulting solid amorphous metal organic framework was placed in a vacuum oven for 1 hour for further drying.

[0431] XRD spectra of the crystalline metal organic framework PCN-250Al and silica comprising the amorphous metal organic framework of example 2 were plotted.

[0432] N.sub.2 adsorption/desorption isotherms and free volume hole size distribution graphs of silica and silica comprising the amorphous metal organic framework of example 2 were plotted.

[0433] As shown in FIG. 4A, the synthesis of example 2 results in the formation of amorphous metal organic framework of aluminium and ABTC. In FIG. 4A, the top line (labelled cPCN-250Al) represents the XRD spectrum of the crystalline metal organic framework PCN-250Al. The Bragg's peaks that are characteristic of this crystalline metal organic framework are clearly visible. In FIG. 4A, the bottom line (labelled Silica with aPCN-250Al) represents the XRD spectrum of the product of example 2. This spectrum contains no Bragg's peaks and as such confirms the amorphous nature of the metal organic framework of example 2.

[0434] The BET surface area for silica was calculated as 191.66 m.sup.2g.sup.−1. The BET surface area for silica comprising the amorphous metal organic framework of example 2 was calculated as 458.89 m.sup.2g.sup.−1. The increase in surface area attributed to the formation of the amorphous metal organic framework of example 2 is therefore 267.23 m.sup.2g.sup.−1 (an increase of 139.43%).

[0435] FIG. 4B shows the full N.sub.2 absorption/desorption isotherms for silica and silica comprising the amorphous metal organic framework of example 2. It is clear that the total quantity of N.sub.2 that is adsorbed by silica comprising the amorphous metal organic framework of example 2 is significantly greater than the total quantity of N.sub.2 adsorbed by silica without the amorphous metal organic framework of example 2. The increase in N.sub.2 adsorption is predominantly due to the increase in surface area provided by the amorphous metal organic frame work of example 2.

[0436] Not only does silica comprising the amorphous metal organic framework of example 2 absorb a greater quantity of N.sub.2, the increase in adsorption is in the most commercially relevant region, i.e. the low pressure region. There is a need to provide materials that adsorb fluids at low partial pressures as this leads to reduced industrial set-up and operating costs.

[0437] FIG. 4B supplemental is an expanded view of FIG. 4B wherein the relative pressure has been limited to the 0-0.5 p/p.sup.o range. In Figure B supplemental the absorption isotherms have been split into two sections: from 0-0.1 p/p.sup.o (region A) and from 0.1-0.42 p/p.sup.o(region B). In region A the increase in adsorption of silica comprising the amorphous metal organic framework of example 2 relative to silica is attributable to the filling of micropores provided by the amorphous metal organic framework of example 2. Importantly, the addition of the amorphous metal organic framework of example 2 provides additional functionality that was not present in clean silica. In particular, adsorption at pressures lower than approximately 0.02 p/p.sup.o.

[0438] The steeper gradient of the curve in region A of the isotherm of activated carbon comprising the amorphous metal organic framework of example 2 indicates that the increase in BET surface area observed is primarily due to an increase in surface area provided by the new micropores (as well as modification of the existing micropores of activated carbon).

[0439] However, the increase in BET surface area is not entirely attributable to new micropore formation. There is also an increase in the adsorption in mesopores. This adsorption is demonstrated by the relative increase in adsorption in region B and is due to the formation of the amorphous metal organic framework of example 2 on the internal surfaces of the mesopores which leads to enhanced multilayer formation. Multilayer formation is the formation of multiple layers of adsorbate on the internal surfaces of the mesopores and is affected by the surface irregularities provided by the formation of the amorphous metal organic framework of example 2 on the internal surfaces of the mesopores.

[0440] The filling of micropores can be split into two groups: primary filling (the filling of micropores with a width of less than 10 Å), and secondary filling (the filling of micropores with a width of between 10 Å and 20 Å). Primary filling is affected by the formation of new micropores or the blocking of existing micropores. Secondary filling is affected by the formation of new micropores, the blocking of existing micropores and the modification of existing micropores (amorphous metal organic framework formation leading to surface irregularities on the internal surfaces of the pores).

[0441] FIG. 4C demonstrates that there is a significant increase in adsorption in the mesopores. This is attributed to enhanced multilayer formation (see FIG. 4C supplemental). FIG. 4C supplemental demonstrates that secondary pore filling is enhanced above approximately 19 Å.

[0442] Silica comprising the amorphous metal organic framework of example 2 therefore exhibits increased low pressure adsorption, increased total adsorption and increased BET surface area relative to clean silica. Importantly, the adsorption ability has been increased in pores with a width of 19-25 Å, at low pressures and greatly over the entire available mesoporous range.

[0443] The SEM image in FIG. 8A shows silica with amorphous metal organic framework of Al and ABTC. There are no crystalline regions observed.

[0444] The EDX image on the left hand side of FIG. 8B shows a low concertation aluminium (aluminium is represented by the white dots on the black background) in clean silica.

[0445] The right hand side of FIG. 8B is an SEI image of clean silica and shows no crystalline regions.

[0446] In contrast to the EDX image on the left hand side of FIG. 8B, the EDX image on the left hand side of FIG. 8C shows a higher concertation aluminium (aluminium is represented by the white dots on the black background) in silica comprising amorphous metal organic framework of Al and ABTC. The right hand side of FIG. 8C is an SEI image of silica comprising amorphous metal organic framework of Al and ABTC and shows no crystalline regions. These images highlight where an increase of aluminium is in the silica showing that the amorphous metal organic framework of Al and ABTC has formed in the pores of the silica and further that these metal organic framework regions are amorphous.

Example 3. Silica Gel with Amorphous Metal Organic Framework of Fe and ABTC

[0447] A mixture of DMF (120 mL), and acetic acid (60 mL) were combined with 1.8 g of ABTC (azobenzene-tetracarboxylic acid) as well as 5.4 g of iron nitrate. The mixture was heated at 150° C. 1.8 g of mesoporous silica gel was added to the mixture once uniform. The combined mixture was placed in a 150° C. oven for two hours. The silica gel comprising amorphous metal organic framework of iron and ABTC was separated under centrifugation and washed using methanol, to remove any impurities. The methanol was discarded and the solid amorphous metal organic framework was collected. The amorphous metal organic framework created was then placed in a vacuum oven for 1 hour for further drying.

[0448] XRD spectra of the crystalline metal organic framework PCN-250Fe and silica gel comprising the amorphous metal organic framework of example 3 were plotted.

[0449] N.sub.2 adsorption/desorption isotherms and free volume hole size distribution graphs of silica gel and silica gel comprising the amorphous metal organic framework of example 3 were plotted.

[0450] As shown in FIG. 5A, the synthesis of example 3 results in the formation of amorphous metal organic framework of iron and ABTC. In FIG. 5A, the bottom line (labelled cPCN-250Fe) represents the XRD spectrum of the crystalline metal organic framework PCN-250Fe. The Bragg's peaks that are characteristic of this crystalline metal organic framework are clearly visible. In FIG. 5A, the top line (labelled Silica Gel with aPCN-250Fe) represents the XRD spectrum of the product of example 3. This spectrum contains no Bragg's peaks and as such confirms the amorphous nature of the metal organic framework of example 2.

[0451] The BET surface area for silica gel was calculated as 496.5969 m.sup.2g.sup.−1. The BET surface area for silica gel comprising the amorphous metal organic framework of example 3 was calculated as 805.5031 m.sup.2g.sup.−1. The increase in surface area attributed to the formation of the amorphous metal organic framework of example 3 is therefore 308.9062 m.sup.2g.sup.−1 (an increase of 62.20%).

[0452] FIG. 5B shows the full N.sub.2 absorption/desorption isotherms for silica gel and silica gel comprising the amorphous metal organic framework of example 3. The increase in N.sub.2 adsorption in the low pressure region (0-0.5 p/p.sup.o) is predominantly due to the increase in surface area provided by the amorphous metal organic frame work of example 3. This adsorption is in the most commercially relevant region, i.e. the low pressure region. There is a need to provide materials that adsorb fluids at low partial pressures as this leads to reduced industrial set-up and operating costs.

[0453] In FIG. 5B, the desorption line for silica gel was corrupted below 0.6 p/p.sup.o. As such, the desorption characteristics of silica gel has not been discussed.

[0454] FIG. 5B supplemental is an expanded view of FIG. 5B wherein the relative pressure has been limited to the 0-0.1 p/p.sup.o range. In FIG. 5B supplemental the absorption isotherms have been split into two sections: from 0-0.01 p/p.sup.o (region A) and from 0.01-0.1 p/p.sup.o(region B). In region A the increase in adsorption of silica gel comprising the amorphous metal organic framework of example 3 relative to silica gel is attributable to the filling of micropores provided by the amorphous metal organic framework of example 3. The steeper gradient of the curve in region A of the isotherm of activated carbon comprising the amorphous metal organic framework of example 3 indicates that the increase in BET surface area observed is primarily due to an increase in surface area provided by the new micropores (as well as modification of the existing micropores of activated carbon).

[0455] The filling of micropores can be split into two groups: primary filling (the filling of micropores with a width of less than 10 Å), and secondary filling (the filling of micropores with a width of between 10 Å and 20 Å). Primary filling is affected by the formation of new micropores or the blocking of existing micropores. Secondary filling is affected by the formation of new micropores, the blocking of existing micropores and the modification of existing micropores (amorphous metal organic framework formation leading to surface irregularities on the internal surfaces of the pores).

[0456] FIG. 5C demonstrates that primary filling increases significantly and that secondary filling decreases for silica gel comprising the amorphous metal organic framework of example 3.

[0457] Silica gel comprising the amorphous metal organic framework of example 3 therefore exhibits increased low pressure adsorption, increased total adsorption and increased BET surface area relative to clean silica gel. Importantly, the adsorption ability has been increased in pores with a width of 5-10 Å and at low pressures. This results in increased small molecule adsorption.

[0458] FIG. 5D shows the full water absorption graph for silica gel and silica gel comprising the amorphous metal organic framework of example 3. The increase in water adsorption in the low pressure region (0-0.4 p/p.sup.o) is predominantly due to the increase in surface area provided by the amorphous metal organic frame work of example 3.

[0459] FIG. 5E is an expanded view of FIG. 5D wherein the relative pressure has been limited to the 0-0.42 p/p.sup.o range. The x-axis in FIG. 5E is different to that of 5D as each x-axis number is separated equally. In contrast the x-axis of FIG. 5D is linear. FIG. 5E demonstrates significant increase in water adsorption in the lower pressure region attributable to the amorphous metal organic framework of example 3 (see the difference in water uptake chart overlay).

[0460] FIG. 5F shows the volumetric methane uptake for silica gel and silica gel comprising the amorphous metal organic framework of example 3.

[0461] It is clear that the uptake volume of methane per volume of silica gel comprising the amorphous metal organic framework of example 3 is significantly greater than the uptake volume of methane per volume of silica gel without the amorphous metal organic framework of example 3 at all pressures. The increase in methane uptake is predominantly due to the change in porosity and possibly due to open metal sites provided by the amorphous metal organic frame work of example 3.

[0462] FIG. 5G shows the gravimetric uptake of methane and methane dosed with 1 mol % hydrogen sulfide. It is clear that the uptake of methane in silica gel comprising the amorphous metal organic framework of example 3 is significantly greater than the uptake of methane in silica gel without the amorphous metal organic framework of example 3. It is clear that the uptake of methane dosed with 1 mol % hydrogen sulfide in silica gel comprising the amorphous metal organic framework of example 3 is significantly greater than the uptake of methane dosed with 1 mol % hydrogen sulfide in silica gel without the amorphous metal organic framework of example 3.

[0463] When tested for gravimetric gas adsorption of methane, silica gel comprising the amorphous metal organic framework of example 3 adsorbed 42.7% less gas than crystalline PCN-250 Fe. When tested for gravimetric gas adsorption of a mixture of 1 mol % hydrogen sulfide in methane, the silica gel comprising the amorphous metal organic framework of example 3 adsorbed 11.3% less gas than crystalline PCN-250 Fe.

Example 4. Activated Carbon with Amorphous Metal Organic Framework of Fe and ABTC

[0464] A mother liquor was prepared for the synthesis of crystalline PCN-250Fe. Once the crystalline PCN-250Fe had been synthesised in the mother liquor the solid PCN-250Fe was removed from the mother liquor by filtration. The remaining mother liquor was then used in the synthesis of an amorphous metal organic framework of Fe and ABTC. The mother liquor may, for example, be obtained from a scaled up method of producing crystalline PCN-250Fe such as one of the methods described in U.S. provisional application 62/662,220. The mother liquor may be the waste slurry described U.S. provisional application 62/662,220.

[0465] Activated carbon was soaked in the mother liquor for 15 minutes. The activated carbon was separated from the mother liquor by filtration. The activated carbon was dried using a vacuum oven at 150° C. for 16 hours before being soaked in the mother liquor for 15 minutes. The activated carbon was separated from the mother liquor by filtration. The activated carbon was then dried using a vacuum oven at 150° C. 16 hours to provide the amorphous metal organic framework of Fe and ABTC.

[0466] XRD spectra of the crystalline metal organic framework PCN-250Fe and activated carbon comprising the amorphous metal organic framework of example 4 were plotted.

[0467] N.sub.2 adsorption/desorption isotherms and free volume hole size distribution graphs of activated carbon and activated carbon comprising the amorphous metal organic framework of example 4 were plotted.

[0468] As shown in FIG. 6A, the synthesis of example 4 results in the formation of amorphous metal organic framework of iron and ABTC. In FIG. 6A, the top line (labelled cPCN-250Fe) represents the XRD spectrum of the crystalline metal organic framework PCN-250Fe. The Bragg's peaks that are characteristic of this crystalline metal organic framework are clearly visible. In FIG. 6A, the bottom line (labelled Activated Carbon with aPCN-250Fe) represents the XRD spectrum of the product of example 4. This spectrum contains no Bragg's peaks and as such confirms the amorphous nature of the metal organic framework of example 4.

[0469] The BET surface area for activated carbon was calculated as 868.4 m.sup.2g.sup.−1. The BET surface area for activated carbon comprising the amorphous metal organic framework of example 4 was calculated as 1077.9 m.sup.2g.sup.−1. The increase in surface area attributed to the formation of the amorphous metal organic framework of example 4 is therefore 209.5 m.sup.2g.sup.−1 (an increase of 24.12%).

[0470] FIG. 6B shows the full N.sub.2 absorption/desorption isotherms for activated carbon and activated carbon comprising the amorphous metal organic framework of example 4. It is clear that the total quantity of N.sub.2 that is adsorbed by activated carbon comprising the amorphous metal organic framework of example 4 is significantly greater than the total quantity of N.sub.2 adsorbed by activated carbon without the amorphous metal organic framework of example 4. The increase in N.sub.2 adsorption is predominantly due to the increase in surface area provided by the amorphous metal organic frame work of example 4.

[0471] Not only does activated carbon comprising the amorphous metal organic framework of example 4 absorb a greater quantity of N.sub.2, the increase in adsorption is in the most commercially relevant region, i.e. the low pressure so region. There is a need to provide materials that adsorb fluids at low partial pressures as this leads to reduced industrial set-up and operating costs.

[0472] FIG. 6B supplemental is an expanded view of FIG. 6B wherein the relative pressure has been limited to the 0-0.5 p/p.sup.o range. In FIG. 6B the absorption isotherms have been split into two sections: from 0-0.1 p/p.sup.o (region A) and from 0.1-0.42 p/p.sup.o(region B). In region A the increase in adsorption of activated carbon comprising the amorphous metal organic framework of example 4 relative to activated carbon is attributable to the filling of micropores provided by the amorphous metal organic framework of example 4. The steeper gradient of the curve in region A of the isotherm of activated carbon comprising the amorphous metal organic framework of example 4 indicates that the increase in BET surface area observed is primarily due to an increase in surface area provided by the new micropores (as well as modification of the existing micropores of activated carbon).

[0473] However, the increase in BET surface area is not entirely attributable to new micropore formation. There is also an increase in the adsorption in mesopores. This adsorption is demonstrated by the relative increase in adsorption in region B and is due to the formation of the amorphous metal organic framework of example 4 on the internal surfaces of the mesopores which leads to enhanced multilayer formation. Multilayer formation is the formation of multiple layers of adsorbate on the internal surfaces of the mesopores and is affected by the surface irregularities provided by the formation of the amorphous metal organic framework of example 4 on the internal surfaces of the mesopores.

[0474] The filling of micropores can be split into two groups: primary filling (the filling of micropores with a width of less than 10 Å), and secondary filling (the filling of micropores with a width of between 10 Å and 20 Å). Primary filling is affected by the formation of new micropores or the blocking of existing micropores. Secondary filling is affected by the formation of new micropores, the blocking of existing micropores and the modification of existing micropores (amorphous metal organic framework formation leading to surface irregularities on the internal surfaces of the pores).

[0475] FIG. 6C demonstrates that primary filling decreases and that secondary filling increases for activated carbon comprising the amorphous metal organic framework of example 4. Furthermore, there is an increase in adsorption in the mesoporous range attributable to enhanced multilayer formation (see FIG. 6C supplemental).

[0476] Activated carbon comprising the amorphous metal organic framework of example 4 therefore exhibits increased low pressure adsorption, increased total adsorption and increased BET surface area relative to clean activated carbon. Importantly, the adsorption ability has been increased in pores with a width of 10-25 Å and at low pressures. This results in increased small molecule adsorption.

Example 5. Silica Gel with Amorphous Metal Organic Framework of Al and ABTC

[0477] A mixture of DMF (120 mL), and acetic acid (60 mL) were combined with 1.8 g of ABTC (azobenzene-tetracarboxylic acid) as well as 3.2 g of aluminium chloride. The mixture was heated at 150° C. 1.8 g of mesoporous silica gel was added to the mixture once uniform. The combined mixture was placed in a 150° C. oven for two hours to dissolve any powders. Every hour, the mixture was shaken to ensure no clumping of powders. The silica gel comprising amorphous metal organic framework of Al and ABTC was separated under centrifugation and washed twice using methanol, to remove any impurities. The solid amorphous metal organic framework was collected and placed in a vacuum oven for further drying.

[0478] The BET surface area was calculated as 516.5 m.sup.2g.sup.−1.

Example 6. Silica Gel with Amorphous Metal Organic Framework of Ti and 2-amino-BDC (L2)

[0479] A mixture of 4.46 g of 2-amino-BDC (L2), and 50 mL of DMF were combined with 13.3 mL of methanol and 20 mL of DMF. The mixture was stirred until the ligand was dissolved. Then, another mixture of 2.22 mL of Ti(IV)-isopropoxide and 50 mL of DMF was prepared. Once the mixture was uniform, the two mixtures were combined and stirred until uniform. In order to produce the amorphous metal organic framework, 4.46 g of macroporous silica gel was added to the mixture. The combined mixture was placed in a 150° C. warm oven for 48 hours to dissolve any powders. Using centrifugations, the aMOF silica was washed three times using DMF and then once using methanol, to remove any impurities. The now solid amorphous metal organic framework was placed in a vacuum oven for further drying, where after the XRD spectra (FIG. 9) was obtained.

Example 7. Silica Gel with Amorphous Metal Organic Framework of Ti and H2BDC

[0480] A mixture of DMF (6.5 mL), and methanol (6.5 mL) were combined with 0.456 g of H2BDC (benzene-1,4-dicarboxylic acid). Then, 1.4 mL of acetic acid was added where after 0.22 mL of Ti(IV)-isopropoxide was added. In order to produce the amorphous metal organic framework, 0.456 g of macroporous silica gel was added to the mixture. The combined mixture was placed in a 110° C. warm oven for 24 hours to dissolve any powders. Using centrifugations, the aMOF silica was washed three times using DMF and then once using methanol, to remove any impurities. The now solid amorphous coordination polymer was collected, placed in a vacuum oven for further drying, where after the PXRD spectra (FIG. 10) was obtained.

Example 8. Activated Carbon with Amorphous Metal Organic Framework of Fe and ABTC

[0481] To create the amorphous metal organic framework, a mixture of distilled water (10 mL) and NaOH (5.03 g) were combined with propan-2-ol (100 mL) and H4-TazBz (18.3 g), after the NaOH was completely dissolved. The mixture was stirred at room temperature until uniform. A mixture of FeCl3(6H2O) (28 g) and propan-2-ol (80 mL) was prepared and then added to the uniform solution. In order to produce the amorphous metal organic framework, 18.3 g of activated carbon was added to the mixture. The resulting mixture was stirred under reflux for 24 hours. Using centrifugations, the aMOF activated carbon was washed three times using distilled water and then three times using ethanol, to remove any impurities. The new solid amorphous coordination polymer collected, was placed in a vacuum oven for further drying, where after BET (FIG. 11B) and PXRD (FIG. 11A) spectra were obtained.

[0482] The BET surface area was calculated as 856 m.sup.2g.sup.−1.