Methods and systems for metal-organic framework synthesis, repair, and lifetime extension for sorptive gas separation applications

Abstract

Method and system for forming, treatment, repair, and / or lifetime extension of self-supported composite sorbents comprising a MOF with a heterocyclic ligand is discussed within the context of use of the composite in gas separation applications.

Description

[0001] METHODS AND SYSTEMS FOR METAL-ORGANIC FRAMEWORK SYNTHESIS, REPAIR, AND LIFETIME EXTENSION FOR SORPTIVE GAS SEPARATION APPLICATIONS

[0002] Field

[0003] The present disclosure relates generally to synthesis or treatment methods for metal-organic framework (MOF) sorbents with a metal, heterocyclic or other carboxylic acid ligands, and systems thereof.

[0004] Background

[0005] Metal-organic frameworks (herein referred as “MOFs”) are a class of network solids composed of organic spacers linking metal ions or metal ion clusters. These materials have a high surface area and tunable pore structures, potentially allowing for their use as a sorbent for sorptive gas separation processes and applications. By changing the organic ligands and metal, the sorption characteristics including, for example, sorptive capacity, guest-selectivity (a sorbent’s selectivity for a target component relative to non-target components), hydrophobicity-hydrophilicity, chemical and steam stability, and / or oxygen stability, can be adjusted to obtain more desirable properties.

[0006] Some sorptive gas separation applications include, but are not limited to, greenhouse gas reduction applications for separation of a target component, for example, an acid gas component, from a gaseous influent stream including, for example, the atmosphere, a combustion or flue gas stream, a biogas stream, or a process gas stream. Particular applications can include carbon capture applications for separating carbon dioxide from the atmosphere, a combustion or flue gas stream, a biogas stream, or a process gas stream, thereby reducing the release of carbon dioxide (CO2) into the atmosphere.

[0007] To carry out a sorptive gas separation function, a MOF sorbent can be configured in a sorbent bed or a sorbent contactor with a high wetted surface area, typically in the form of thin sheets, thin wall extrudates, or as pellets. The MOF sorbent can be synthesized separately and then applied to a substrate (also referred to as a support). Alternatively, the MOF can be mixed with binders and a diluent, extruded to form, for example, a sheet or a monolith extrudates, then dried and activated, to create a MOF sorbent.

[0008] An influent or feed stream of a sorptive gas separation process in some applications can comprise a dilute concentration of a target component, for example, less than 25 mole percent of the target component such as CO2. In some applications, the feed stream can also include oxygen, and / or water, which can offer challenges including, for example, guest-selectivity and stability of the sorbent when exposed to oxygen and / or water, which can trigger a phase change of the MOF and / or sorbent.

[0009] In some sorptive gas separation processes employing, for example, temperature swing and / or moisture swing, water in the form of steam can be used to desorb the sorbed target component from the sorbent, regenerating the sorbent for a subsequent sorbing step. Steam offers the advantage of rapidly conveying heat and / or moisture to the sorbent resulting in shortening the duration of the desorbing step and enabling rapid cycling of the gas separation process. However, the use of steam exposes the sorbent to water or moisture at elevated temperatures.

[0010] The exposure of the MOF to different process streams while subjecting the MOF to at least one of heat; temperature swings, for example, of up to about 100°C; contaminants or chemical impurities in the gas stream, such as, SOx and NOx; steam; and water, can lead to sublimation and / or loss of MOF ligands. This can result in the collapse of the MOF’s crystalline structure and a significant loss of the MOF’s porosity, sorptive separation capacity, function, and / or lifetime.

[0011] CALF-20, a MOF comprising zinc, oxalate and 1,2,4-triazole, has shown this type of degradation, resulting in progressive loss of function, sorptive capacity, and crystallinity, which starts typically at one end of the sorbent bed and can progressively expand along the sorbent bed during use.

[0012] These phenomena can reduce the lifetime of the MOF sorbent and increases the cost of the sorptive separation process. Brief Description of the Drawings

[0013] Figure 1 presents a loss in sorption capacity for spent CALF-20 metalorganic framework (MOF) sorbent samples from two sorptive separators after about 3500 hours of operation under sorption-desorption cycles;

[0014] Figures 2a, 2b, and 2c presents energy dispersive X-ray spectra (EDS) mapping images of three MOF sorbent samples, Fig. 2a is an EDS image of a fresh MOF sorbent sample, Fig. 2b is an EDS image of a spent MOF sorbent sample obtained from a sorbent bed of a sorptive separator depleted in triazole, and Fig. 2c is an EDS image of a repaired MOF sorbent sample after exposure to a heterocyclic solution;

[0015] Figures 3a, 3b, 3c, 3d, 3e, and 3f are scanning electron microscopy (SEM) images of the surface of MOF sorbent samples at 10,000X and 1,000X magnifications. Fig. 3a is a SEM image of a fresh MOF sorbent sample at 10,000X magnification. Fig.

[0016] 3b is a SEM image of the fresh MOF sorbent sample shown in Fig. 3a at 1 ,000X magnification. Fig. 3c is a SEM image of a spent MOF sorbent sample at 10,000X magnification. Fig. 3d is a SEM image of the spent MOF sorbent sample shown in Fig.

[0017] 3c at 1 ,000X magnification. Fig. 3e is a SEM image of a repaired MOF sorbent sample at 10,000X magnification. Fig. 3f is a SEM image of the repaired MOF sorbent sample shown in Fig. 3e at 1,000X magnification.

[0018] Figure 4 presents an X-Ray diffraction diagram for fresh, spent and repaired MOF sorbent samples;

[0019] Figure 5a is a thermogravimetric analysis (TGA) profile of a spent MOF sorbent sample before repair;

[0020] Figure 5b is a thermogravimetric analysis (TGA) profile of a spent MOF sorbent sample after repair;

[0021] Figure 6 is a graph of showing the sorptive capacity of CO2 or water at 0%, 10%, and 20% relative humidity of a repaired MOF sorbent sample compared to a fresh MOF sorbent sample;

[0022] Figure 7a is a cross-sectional view illustrating treatment or repair of a sorbent bed with a metal-organic framework (MOF) sorbent removed from a sorptive separator; and more specifically, spent MOF sorbent with passages is in an enclosure, with spent MOF sorbent configured substantially vertically over a heterocyclic solution and in a vapor according to an embodiment of the invention;

[0023] Figure 7b is a cross-sectional view similar to Fig. 7a, however illustrating spent MOF sorbent configured with passages substantially horizontally over heterocyclic solution and in vapor according to an embodiment of the invention;

[0024] Figure 7c is a cross-sectional view similar to Figs. 7a and 7b, however illustrating a spent MOF sorbent with passages is submerged in a heterocyclic solution in an enclosure according to an embodiment of the invention;

[0025] Figure 8a is a schematic diagram of a sorptive separation system fluidly connected to supply a feed stream from a feed stream source in a counter-flow direction relative to a desorption stream from regeneration stream source into a sorbent bed 1 , with a heterocyclic fluid source fluidly connected to supply a heterocyclic fluid in a coflow direction with a regeneration stream into sorbent bed according to an embodiment of the invention, and

[0026] Figure 8b is a schematic diagram of a sorptive separation system fluidly connected to supply a feed stream from a feed stream source in a co-flow direction relative to a regeneration stream from regeneration stream source 63 into a sorbent bed, where a heterocyclic fluid source is fluidly connected to supply a heterocyclic fluid in a co-flow direction with a regeneration stream into sorbent bed according to an embodiment of the invention.

[0027] Summary

[0028] In a first broad aspect, a method for forming, treating, or repairing a metalorganic framework (MOF) sorbent comprises at least one of contacting and reacting a MOF precursor with an aromatic heterocyclic fluid comprising an aromatic heterocyclic molecule or compound, wherein the MOF precursor further comprises at least one of a metal ion, or a metal cluster, and an organic ligand or a carboxylate ligand. In embodiments, the MOF precursor comprise a sub-stoichiometric quantity of heterocyclic ligands. In a second broad aspect, a sorptive gas separation process comprises: (a) admitting a feed stream into a sorptive separator comprising at least one MOF sorbent, sorbing at least a portion of the first component from the feed stream on and / or in the at least one MOF sorbent to form a first product stream depleted in the first component relative to the feed stream, and recovering the first product stream from the sorptive separator;

[0029] (b) desorbing at least a portion of the first component from the at least one MOF sorbent to form a second product stream enriched in the first component relative to the feed stream, and recovering the second product stream from the sorptive separator, and

[0030] (c) admitting an aromatic heterocyclic molecule or compound into the sorptive separator, contacting the aromatic heterocyclic molecule or compound with the at least one MOF sorbent.

[0031] In a third broad aspect, a sorptive gas separation system comprises: (a) a feed stream source for providing a feed stream having at least a first component and a second component;

[0032] (b) a sorptive separator having at least one fluid passage and a MOF sorbent, wherein the MOF sorbent is at least periodically fluidly connected to the feed stream source for receiving the feed stream, and

[0033] (c) a heterocyclic fluid source, wherein the MOF sorbent is at least periodically fluidly connected to the heterocyclic fluid source for receiving an aromatic heterocyclic molecule or compound therefrom.

[0034] In another broad aspect, a MOF treatment system for treating or repairing a MOF sorbent comprises:

[0035] (a) a heterocyclic fluid source, for supplying a heterocyclic fluid comprising an aromatic heterocyclic molecule or compound;

[0036] (b) an enclosure for confining at least a portion of the MOF sorbent and at least a portion of the heterocyclic fluid, and

[0037] (c) a heat source for supplying heat to the heterocyclic fluid, wherein the heterocyclic fluid is at least periodically in contact with the MOF sorbent and the heating source is thermally connected to the heterocyclic fluid.

[0038] Description

[0039] Definitions

[0040] MOF: metal-organic framework.

[0041] MOF sorbent: a sorbent incorporating a MOF.

[0042] CO2: carbon dioxide.

[0043] CALF-20: metal-organic framework, a crystalline material with a general composition Zn2Tz20x, with Zn a zinc2+cation, Tz 1 ,2,4-triazolate ligand, Ox an oxalate ligand.

[0044] Self-supported composite: a sorbent attached to a support or a substrate, a macroscopic object that can be supported at one edge of the object without fracturing due to gravitational forces on the unsupported portions of the object.

[0045] Sorbent: a material in a solid phase which can selectively adsorb and / or absorb a target component from a multi-component gas stream or feed stream. The sorbent can be supported on and / or in a support or can be unsupported without the use of a support.

[0046] Sorbent bed: comprises a sorbent typically stationary in relation to the sorbent bed. A sorptive separator can comprise at least one sorbent bed wherein the sorbent bed can be moving or stationary within the sorptive separator. A sorbent bed can be configured with sheets or plates, an extrudate, a monolith, or packing structures for forming a packed bed. The term sorbent bed can also refer to and used interchangeably as a bed, a sorbent structure, a contactor, or a sorbent contactor.

[0047] Spent MOF: a MOF sorbent with at least one of a reduced sorptive capacity and change in crystalline structure relative to a fresh or new MOF sorbent which can be a result of exposure to steam, water, heat and / or contaminates, for example, NOx and / or SOx. Exposure typically occurs during use of the MOF as a sorbent but can occur prior to use of the MOF sorbent.

[0048] Repaired MOF: a MOF sorbent after ligands are reincorporated into a spent MOF sorbent. Substrate: a support for a sorbent, wherein the sorbent can be attached on and / or in the substrate or support. The term “substrate” can be used interchangeably with the term “support”.

[0049] MOF precursor: a MOF and / or a MOF sorbent with a sub-stoichiometric quantity of at least one ligand relative to an original or target quantity of ligands which can be measured by, for example, nuclear magnetic resonance (NMR), or energy-dispersive x-ray spectroscopy (EDS). A MOF precursor can be a fresh MOF or a spent MOF with a reduced or less than desirable quantity of at least one ligand. A MOF precursor can be a neat MOF (a MOF without a sorbent support) or a MOF on and / or in a support such as a self-supported composite.

[0050] Laminate: a substrate with one or more MOFs attached to the substrate.

[0051] Heterocyclic ligand: a ligand comprising at least a ring as 3- or 4- or 5- or 6-membered carbon ring substituted with atoms other than carbon as a part of the ring, for example, N, O, S, P, but not limited to these atoms.

[0052] RH: relative humidity.

[0053] MeOH: methanol.

[0054] DI: deionized water.

[0055] m2 / m3: square meters per cubic meter

[0056] The present disclosure relates generally to synthesis or treatment methods for metal-organic frameworks (MOFs) with a metal, heterocyclic or other carboxylic acid ligands, and systems thereof. The MOFs can be used as a sorbent and configured in a structured form including extrudates, laminates and membranes for sorptive gas separation applications. The synthesis methods can also be used to reduce aging and / or repair spent MOF sorbents. The methods can partially or substantially recover the crystallinity and the porosity of a spent MOF relative to a fresh MOF. Systems for conducting the synthesis methods are also disclosed.

[0057] A designed lifetime of a sorbent bed can be in the range of about 2 to 4 years, prior to replacement. Maintaining and / or extending the lifetime of a MOF sorbent by maintaining or recovering the characteristics of the MOF sorbent such as porosity and sorption capacity can be desirable. The present disclosure addresses the issues of the sublimation and / or at least one of steam, water, and heat assisted loss of at least one ligand from a MOF for gas separation processes using sorbents in sorptive or membrane devices. The loss of ligands can reduce a lifetime of a MOF sorbent resulting in downtime for the sorptive separator, and increasing the operating costs, for example, costs for replacing the sorbent and / or sorbent bed.

[0058] Typical synthesis of a MOF sorbent involves a solvothermal reaction (typically at temperatures in a range of 25°C to 200°C and at pressures in a range of 1 to 3 bars absolute) of components (metal and organic molecules) in a closed reaction vessel. A conventional approach to producing a structured sorbent (referred to as a self-supported composite herein) comprising a MOF includes the steps of synthesizing a MOF, combining the MOF with binders and additives for producing a slurry, and coating a sorbent support with the slurry for forming a laminate or a structured sorbent.

[0059] A structured sorbent can be used in a sorptive gas separation process where the MOF sorbent is subjected to repetitive sorption-desorption cycles. In some sorptive gas separation processes, steam can be used for regeneration of the MOF sorbent. The repeated sorption-desorption cycles and / or exposure to steam can cause sublimination and the MOF sorbent to lose some of its ligands resulting in a spent MOF.

[0060] A spent MOF in a sorbent bed (for example, a MOF sorbent with binders and additives on a support) can be repaired by extracting or isolating the MOF sorbent from the sorbent bed, the extraction or isolation procedure can cause a significant time delay and other handling complexities.

[0061] Methods of repairing a spent MOF or a structured sorbent comprising a MOF sorbent without extracting or isolating the spent MOF from a sorptive separator or a sorbent structure is disclosed. Repair can be conducted by directly treating the spent MOF in a sorbent bed. This offers a direct method to repair the sorbent beds without having to dismantle a sorptive separator or sorbent bed. In some methods, the repair can be conducted without terminating the operation of the bed. The method of repair can work for sorbent beds with a MOF sorbent comprising additives, and binders and can be applied other MOFs comprising heterocyclic and carboxylate ligands. Methods to repair a spent MOF separated from a sorbent bed are also disclosed. Methods and systems for forming a MOF sorbent, for forming a MOF sorbent from a MOF precursor, adding ligands to a MOF sorbent, and changing the crystalline structure of a MOF precursor and / or MOF sorbent are also disclosed. The addition of ligands to a MOF precursor and / or MOF sorbent can be used but not limited to, for example, repairing of a MOF sorbent by replacing, reloading, and / or reincorporating ligands which can be lost due to chemical degradation and / or for adding ligands prior use. MOFs can be used as a sorbent and configured within a sorbent bed comprising on and / or in a sorbent support, for example, one or more sheets, a monolith, an extrudate or a packing material for forming a packed bed. The sorbent bed can be used for sorptive gas separation processes and sorptive separators for separation of a first component, for example, an acid gas component such as carbon dioxide, from a multi-component gas stream, for example, a flue gas, a combustion gas, ambient air, a process gas, or a biogas. A MOF precursor comprising an amorphous, partially amorphous, or partially crystalline structure with a sub-stoichiometric quantity or a less than a desired quantity of ligands can be used as a base material for creating a MOF sorbent with a desired quantity of ligands and / or crystalline structure. A MOF sorbent can be attached on and / or in a support which is porous. The MOF precursor can be a spent MOF where a sorption capacity of the spent MOF was reduced or lost due to chemical degradation leading to the loss of ligands by sublimation, and / or exposure to at least one of steam, water, heat, chemical contaminants in the gas stream, such as, SOx and / or NOx, during use, such as, during sorption-desorption steps or due to transformation of phases of components of a MOF sorbent. Additionally, the repair process can be performed on a MOF sorbent chemically damaged by contaminants, for example, from contaminants in an influent gas stream to a sorptive separator.

[0062] Furthermore, methods and systems disclosed herein can be used to extend or increase the lifetime of a MOF sorbent due to loss of ligands and / or change in the MOFs structure, for example, from crystalline to amorphous. The present invention can also be used to synthesize or repair composite membrane materials comprising a MOF sorbent after a loss of ligands and / or a phase change.

[0063] Some MOF sorbents are known to become amorphous, partially amorphous, or partially crystalline when exposed to water, steam, heat, and / or a reactive contaminant, such as NOx and / or SOx, which can be present in an influent gas stream admitted to a sorptive separator. This mechanism can result in the loss of porosity and / or sorption capacity. A loss of one of the ligands was discovered for CALF-20 when CALF-20 was subjected to a large flow volume of steam for thousands of hours.

[0064] Fig. 1 is a graph with the y-axis representing a loss in sorption capacity (as a percentage of a total sorption capacity) of CALF-20 MOF samples (herein referred to as “MOF samples” or “samples”) and the x-axis representing a distance (as a percentage of a total bed length of a sorptive separator) from an end of the sorptive separator where steam was admitted during regenerating or desorbing steps of a sorptive process. Tests were conducted on two sorptive separators, wherein each sorptive separator comprise two beds configured in series where the flow of the steam enters and flows through a first bed and then through a second bed. The loss in sorption capacity in a first bed of a first sorptive separator are shown as columns 10, and in a second bed of the first sorptive separator are shown as columns 11. The loss in sorption capacity in a first bed of a second sorptive separator are shown as columns 12, and in a second bed of the second sorptive separator are shown as columns 13. The sorptive separators and beds were operated for about 3500 hours under sorptiondesorption cycles, sorbing CO2 and using steam at substantially atmospheric pressure during desorption. Loss of sorption capacity is shown as a percentage relative to a sorptive capacity of a fresh (prior to use or a new) sample. Fig. 1 shows the steam end of the sorptive separator (end which steam is admitted) incurs a larger loss in sorption capacity relative to the rest of the sorptive separator.

[0065] Figs. 2a, 2b, and 2c are Energy Dispersive X-ray Spectra (EDS) mapping images of three MOF sorbent samples. Fig. 2a is an image of a fresh or new MOF sorbent sample. Fig. 2b is an image of a spent MOF sorbent sample obtained from a steam end of a sorbent bed. Fig. 2c is an image of a repaired MOF sorbent sample after exposure to a heterocyclic fluid or solution comprising 1,2,4-triazole, methanol, and water. In Fig. 2b, the spent MOF sample exhibits fewer nitrogen atoms and greater oxygen atoms on a proportionate basis relative to the fresh MOF sample in Fig. 2a. A quantitative analysis reveals that the reduction in quantity of the nitrogen atoms in the spent MOF sample was due to the removal and loss of ligands comprising nitrogen. The spent MOF sample also presents a densification of the solid phase with an extended network of macropores in the composite structure relative to the fresh sample. Fig. 2c shows the repaired MOF sample exhibiting more nitrogen atoms on a proportionate basis relative to the spent MOF sample in Fig. 2b.

[0066] In embodiments, methods for forming, treating, or repairing a MOF sorbent can comprise adding ligands to a MOF, and / or changing the MOFs structure by converting at least a portion of the amorphous structure to a crystalline structure. The adding of ligands can be used for replacing and / or reincorporating ligands lost from a spent MOF. In one embodiment, the converting of the at least a portion of the amorphous structure to a crystalline structure of a MOF can repair the amorphous structure to substantially the same crystalline structure as the MOFs original crystalline structure. In an embodiment, the method can comprise a step of contacting a spent MOF with a heterocyclic fluid or solution comprising, for example, 1 ,2,4-triazole or other 1.2.4-triazole derivatives, methanol and water. In one aspect, the heterocyclic fluid or solution can comprise at least one of 1,2,4-triazole, 3-amino-1 ,2,4-triazole, 3-methyl- 1.2.4-triazole, and other 1 ,2,4-triazole derivatives. In another aspect, contacting the spent MOF with the heterocyclic fluid can be conducted in-situ, such as, contacting the spent MOF with the heterocyclic fluid while the spent MOF is in a sorptive separator and / or in a bed. Reincorporating ligands after the ligands were stripped and lost from the MOF and re-arrangement of pore volume distribution within the sorbent can be achieved with the methods disclosed. In one aspect, the MOF sorbent can be attached on and / or in a support or substrate including but not limited to, for example, a woven carbon fiber sheet.

[0067] Methods and systems for forming, treating, or repairing a MOF sorbent within a sorptive separator or removed from a sorptive separator are disclosed.

[0068] In an embodiment, a method for forming, treating or repairing a metalorganic framework (MOF) sorbent can comprise the step of at least one of contacting and reacting a MOF precursor comprising a metal ion or a metal cluster, and an organic ligand or a carboxylate ligand, with an aromatic heterocyclic fluid comprising an aromatic heterocyclic molecule or compound. In aspects, at least one of, the MOF precursor can comprise a sub-stoichiometric quantity of heterocyclic ligands, the MOF precursor can be at least partially amorphous, amorphous, partially crystalline, or crystalline. In one aspect the contacting and / or reacting can be at a temperature in a range of about 10°C to about 200°C or preferably about 25°C to about 180°C. In another aspect the contacting and / or reacting can be at a temperature greater than about 50°C, 80°C, 120°C, or 160°C. In another aspect, the MOF sorbent can comprise an aromatic heterocyclic ligand; a metal ion or a metal cluster; and an organic ligand or a carboxylate ligand. In one aspect, the metal ion or the metal cluster comprise zinc. In yet another aspect, the MOF sorbent can comprise a crystalline structure. In an aspect, the aromatic heterocyclic molecules or compounds can be the same in the aromatic heterocyclic fluid and the aromatic heterocyclic ligand. In an aspect, the aromatic heterocyclic molecules or compounds can be an aromatic heterocyclic molecules or compounds of the aromatic heterocyclic ligand. In another aspect, the aromatic heterocyclic molecules or compounds can be 1,2,4-triazole, 3-amino-1,2,4-triazole, 3-methyl-1 ,2,4-triazole, or other 1 ,2,4-triazole derivatives. In one aspect the aromatic heterocyclic fluid is in a liquid phase, in a vapor phase, a mist, or a dispersion of solids in a liquid, such as, a solvent. In one aspect, a concentration of aromatic heterocyclic molecules or compounds in the heterocyclic fluid or solution in a liquid phase can be in a range of 0.03 moles per liter (M) to 0.67 moles per liter (M). In yet another aspect, the contacting of the MOF precursor with the aromatic heterocyclic fluid stream can be a step of adding the aromatic heterocyclic molecule or compound to the MOF precursor. In another aspect, the MOF sorbent is in and / or on a substrate which is porous. In another aspect, the substrate comprises a wetted surface area equal to or greater than 200 square meters per cubic meter. In an embodiment, at least one of, the MOF, the MOF sorbent, and the MOF precursor can be CALF-20, a MOF in the CALF-20 family, or CALF-20 wherein the 1 ,2,4-triazolate is replaced by at least one of 3-amino-1 ,2,4-triazolate or 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3,5-diamino-1 ,2,4-triazolate, 3,5-dimethyl-1 ,2,4-triazolate, 3,5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate. In another embodiment, the method can further comprise the step of controlling a temperature of the at least one of contacting and reacting. In an embodiment, the method can further comprise prior to the at least one of contacting and reacting a MOF precursor, a step of combining the aromatic heterocyclic fluid with a solvent or a carrier gas. In one aspect the solvent is at least one of methanol, water, an organic-based solvent, and an alcohol-based solvent; and the carrier gas is at least one of steam, nitrogen, helium, and air. In another aspect, the solvent comprises methanol with a concentration of equal to or greater than 1 % by volume of the solvent. In an embodiment, the method can comprise at least one of: conducting the at least one of contacting and reacting for a duration in a range of 1 minute to 24 hours; conducting the at least one of contacting and reacting at a pressure equal to or greater than about atmospheric pressure or at solvothermal conditions; placing the MOF precursor over the heterocyclic fluid, diffusing the heterocyclic fluid into the MOF precursor, and submerging the MOF precursor into a bath of a heterocyclic fluid. In one aspect, the MOF precursor is formed by subjecting the MOF sorbent or the MOF precursor to at least one of steam, heat, and sorption-desorption cycles. In one aspect, the MOF sorbent can be used as a sorbent for a sorptive gas separation process in a sorptive separator for separating of a first component, for example, carbon dioxide from a multi-component gas stream.

[0069] In an embodiment, a method for forming or treating a metal-organic framework (MOF) sorbent, the method can comprise the following steps:

[0070] • contacting and / or reacting a MOF precursor comprising a metal cation, and an organic ligand or a carboxylate ligand, with an aromatic heterocyclic fluid comprising an aromatic heterocyclic molecule or compound, • wherein the contacting and / or reacting the MOF precursor with the aromatic heterocyclic molecule or compound can be at a temperature greater than about 50°C, 80°C, 120°C, or 160°C; or at a temperature in a range of about 10°C to about 200°C or preferably about 25°C to about 180°C.

[0071] In an embodiment, the method can comprise forming or treating the MOF sorbent on and / or in a porous substrate. In an aspect, the MOF precursor can be in and / or on a porous substrate. In another aspect, the porous substrate can comprise a wetted surface area equal to or greater than about 200 square meters per cubic meter (herein referred to as “m2 / m3”) of the porous substrate. In one aspect, the aromatic heterocyclic fluid can be at least one of a liquid phase, a vapor phase, a mist, and dispersion of solids in a liquid such as a solvent. In an embodiment, wherein the step of reacting can comprise reacting a crystalline and / or an amorphous fraction of the MOF precursor with the aromatic heterocyclic molecule or compound. In another embodiment, the step of reacting can occur at a pressure equal to or greater than about atmospheric pressure or at solvothermal conditions. In aspects, the MOF sorbent can comprise at least one of: a porous crystalline structure or phase with a heterocyclic ligand, an organic ligand or a carboxylate ligand, and a metal ion or a metal cation; and a MOF weight equal to or greater than about 50% by weight of a total weight comprising the MOF weight and a weight of the substrate. In aspects, the MOF precursor, or the MOF sorbent can be CALF-20 or any MOF in the CALF-20 family, including, for example, CALF-20 wherein the 1 ,2,4-triazolate is replaced by at least one of 3-amino-1 ,2,4-triazolate, 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3, 5-diamino-1 ,2,4-triazolate, 3,5-dimethyl-1,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate. In one aspect, the heterocyclic fluid or solution can comprise at least one of 1,2,4-triazole, 3-amino-1 ,2,4-triazolate, 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3,5-diamino-1,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate.

[0072] In further embodiments of the method for forming, treating, or repairing a MOF sorbent can comprise, forming the MOF precursor by a step of stripping the heterocyclic ligand from a MOF crystal or a crystalline structure of the MOF precursor by, for example, exposing the MOF precursor to steam, and / or heat. In one aspect, forming the MOF precursor can be achieved by subjecting a MOF sorbent to a plurality of sorption-desorption cycles of a gas separation process which can resulting in a reduction in a sorptive capacity of the MOF sorbent relative to a sorption capacity a fresh or new MOF sorbent.

[0073] In an embodiment, a method for forming a MOF sorbent on and / or in a substrate which is porous, the method can comprise the steps of reacting a metal cation with an organic ligand or a carboxylate ligand, in a solution for forming a MOF slurry, precipitating the MOF slurry from the solution for forming a solid, recovering the solid, coating or impregnating the solid in and / or on the porous substrate. In an embodiment, the method can comprise at least one of the steps of drying the solid and activating the solid. In aspects, the porous substrate can comprise a wetted surface area equal to or greater than about 200 m2 / m3.

[0074] In another embodiment, the method for forming a MOF sorbent on and / or in a porous substrate can further comprise forming a MOF precursor prior to the step of reacting, which can comprise a step of co-precipitating the metal cation and an organic ligand precursor or a carboxylate ligand precursor on a substrate which is porous. In an embodiment, conducting the co-precipitating can be by, for example, submersing the substrate in a solution with the metal cation and the organic ligand or the carboxylate ligand. In one embodiment, the method can further comprise a step of washing the MOF precursor. In some aspects, the washing can be conducted with water or a solvent with a low boiling point, for example, methanol or ethanol. In one aspect, the porous substrate can comprise a wetted surface area equal to or greater than about 200 m2 / m3of the porous substrate. In aspects, the MOF can be CALF-20 or any MOF in the CALF-20 family, including, for example, CALF-20 wherein the 1 ,2,4-triazolate is replaced by at least one of 3-amino-1 ,2,4-triazolate, 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3, 5-diamino-1 ,2,4-triazolate, 3,5-dimethyl-1 ,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate. In one aspect, the solution can comprise an organic ligand or a carboxylate ligand, with methanol, water, or a suitable organic-based or alcohol-based solvent and any combination thereof.

[0075] In embodiments, a method for forming a MOF sorbent from a MOF precursor comprising an organic ligand or a carboxylate ligand, a metal cation, and a heterocyclic ligand, can comprise the steps of contacting the MOF precursor with a heterocyclic fluid comprising at least one aromatic heterocyclic molecules or compounds and at least one of a solvent, or a carrier gas for reincorporating a desired quantity of heterocyclic ligand and / or forming a desired crystal structure or phase of the MOF sorbent. In an embodiment, the method can further comprise during and / or after the contacting step, a step of reacting the MOF precursor and heterocyclic fluid at a temperature greater than about 50°C, 80°C, 120°C, or 160°C; or at a temperature within a range of about 10°C to about 200°C or preferably about 25°C to about 180°C. In an aspect, the reacting can occur at a pressure equal to or greater than about atmospheric pressure or at solvothermal conditions. In one aspect, the MOF precursor can comprise an organic ligand or a carboxylate ligand, a metal cation, and a heterocyclic ligand, with a sub-stoichiometric quantity of heterocyclic ligands relative to an original or target quantity of heterocyclic ligands which can be measured by, for example, nuclear magnetic resonance (NMR), or energy-dispersive x-ray spectroscopy (EDS). In another aspect the aromatic heterocyclic fluid can be in a liquid phase, a mist, a vapor phase, or dispersion of solids in a liquid. In aspects, at least one of: the solvent can be methanol, water, or a suitable organic-based or alcohol-based solvent and any combination thereof; and the carrier gas can be steam, nitrogen, helium, air, other suitable inert gas, or any combination thereof. In an aspect, the MOF precursor can be in and / or on a porous substrate. In another aspect, the porous substrate can comprise a wetted surface area equal to or greater than about 200 m2 / m3of the porous substrate. In aspects, the MOF can be CALF-20 or any MOF in the CALF-20 family, including, for example, CALF-20 wherein the 1 ,2,4-triazolate is replaced by at least one of 3-amino-1 ,2,4-triazolate, 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3, 5-diamino-1 ,2,4-triazolate, 3,5-dimethyl-1,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate. In one aspect, the heterocyclic fluid or solution can comprise at least one of 1,2,4-triazole, 3-amino-1 ,2,4-triazolate, 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3,5-diamino-1,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate.

[0076] MOFs and / or MOF sorbents with a sub-stoichiometric quantity of heterocyclic ligands due to loss relative to an original or target quantity of heterocyclic ligands can be at least partially reversed by adding ligands to the MOF and / or the MOF sorbent (thereby replacing, reloading, and / or reincorporating the lost ligands) and / or reforming the crystalline structure of the MOF resulting in repairing of the MOF and / or the MOF sorbent. A method for repairing or treating a MOF sorbent while in a sorptive separator (herein referred to as “in-situ”) on a continuous or intermittent basis can be desirable. However for some applications, the in-situ method offers challenges including, for example, managing emissions of the aromatic heterocyclic molecules or compounds from a sorptive separator during the repair method, and / or limiting the exposure of components of the sportive separator and / or the sorptive separation system to potentially harmful fluids such as a solvent or a carrier gas for the aromatic heterocyclic molecule or compound used during the repair. The quantity of ligands in a MOF and / or a MOF sorbent can be measured by, for example, nuclear magnetic resonance (NMR), or energy-dispersive x-ray spectroscopy (EDS).

[0077] An alternative to the in-situ treatment or repair method, at least a fraction of a sorbent bed or MOF sorbents from a sorptive separator can be periodically removed from the sorptive separator and exposed to the aromatic heterocyclic molecule or compound while separated from the sorptive separator. This method can be applicable to sorptive separators with sorbent beds comprising a single sorbent structure or an assembly of sorbent structures, for example, blocks, modules, or segments, where individual sorbent structures can be separated from, removed, and reinstalled into the sorptive separator. For sorbent beds comprising a plurality of sorbent structures, an advantage of this method can be enabling the repair and treatment of individual sorbent structures as opposed to all sorbent structures of a sportive separator, and / or customized treatment of one or more sorbent structures depending on the degradation of the individual sorbent structure. After repair, the sorbent structure can be re-installed and reused in the sorptive separator.

[0078] In an embodiment a method of treating or repairing a MOF sorbent with an organic ligand or a carboxylate ligand, a metal cation, and a heterocyclic ligand, the method can comprise a step of contacting the MOF sorbent with a heterocyclic fluid comprising at least one aromatic heterocyclic molecule or compound of the heterocyclic ligand. In an embodiment, the method can further comprise during and / or after the contacting step, contacting and / or reacting the MOF sorbent and heterocyclic fluid at a temperature greater than about 50°C, 80°C, 120°C, or 160°C; or at a temperature within a range of about 10°C to about 200°C or preferably about 25°C to about 180°C. In an aspect, the contacting and / or reacting can occur at a pressure equal to or greater than about atmospheric pressure or at solvothermal conditions. In another aspect the aromatic heterocyclic fluid can be in a liquid phase, a mist, a vapor phase, or dispersion of solids in a liquid, such as, a solvent. It can be desirable to physically contact the aromatic heterocyclic molecules or compounds with the MOF sorbent in a manner which enable molecules of the aromatic heterocyclic molecules or compounds to diffuse into the MOF sorbent and react with the metal cation, and an organic ligand or carboxylate ligand, which can be in a form of an amorphous precipitate. In embodiments, contacting of the aromatic heterocyclic molecules or compounds with the MOF sorbent can be achieved by but not limited to, for example, placing the MOF sorbent over a heterocyclic fluid or solution comprising the aromatic heterocyclic molecules or compounds (optionally in an enclosure for substantially confining the MOF sorbent and / or heterocyclic fluid or solution), converting the heterocyclic fluid or solution to a vapor phase for forming a vapor (for example, by at least one of heating and mechanical agitation of the heterocyclic fluid or solution) and diffusing the vapor into and in contact with the MOF; flowing the heterocyclic fluid or solution in a form of a liquid, a mist, a vapor, and / or a dispersion of solids in a liquid and contacting the MOF sorbent; or mixing the heterocyclic fluid or solution in a form of a liquid, a mist or a vapor with a carrier gas to form a mixed heterocyclic stream and flowing the mixed heterocyclic stream and contacting the MOF sorbent. In another embodiment, after contacting the aromatic heterocyclic molecules or compounds with the MOF sorbent, the method can further comprise the step of removing excess heterocyclic fluid or solution from the MOF sorbent, thereby repairing the MOF sorbent. The excess heterocyclic fluid or solution can be recovered for reuse. In an embodiment, method can further comprise at least one of the steps of washing and drying the MOF sorbent before reinstalling the MOF sorbent into the sorptive separator. Referring to Fig. 7a and Fig. 7b, in an embodiment, a sorbent bed or a contactor 83 comprising a spent MOF and a plurality of passages 84 can be placed in an enclosure 80 over a heterocyclic solution 81. In Fig. 7a, contactor 83 is configured with the plurality of passages 84 in a substantially vertical position over the heterocyclic solution 81 and in a vapor 82 which can flow and diffuse into plurality of passages 84 and in contact with contactor 83 and the spent MOF. In Fig. 7b contactor 83 is configured with the plurality of passages 84 in a substantially horizontal position over the heterocyclic solution 81 and in vapor 82 which flows and diffuses into plurality of passages 84 and in contact with contactor 83 and the spent MOF. Contactor 83 can be configured with the passages in other suitable positions and is not limited to the vertical or horizontal positions. In one aspect, the heterocyclic fluid or solution can comprise at least one of 1 ,2,4-triazole, 3-amino-1 ,2,4-triazole, 3-methyl-1 ,2,4-triazole, and other 1 ,2,4-triazole derivatives.

[0079] In an embodiment, the method of treating or repairing a MOF sorbent or spent MOF, can comprise submerging the MOF sorbent or the spent MOF into a bath of a heterocyclic fluid or solution comprising the aromatic heterocyclic molecules or compounds, and a solvent. In one aspect the solvent can comprise methanol and water, other suitable organic or alcohol-based solvents, or other suitable organic or alcohol-based solvents and water. In another aspect the solvent can comprise equal to or greater than about 1%, 2%, or 10% by volume of methanol in relation to the methanol and water mixture. In aspects, at least one of, a temperature of the solvent can be at a temperature within a range of about 10°C to about 200°C, or preferably about 25°C to about 180°C, and the method can comprise a step of flowing, agitating, stirring, or spinning the heterocyclic fluid or solution in the bath. The heterocyclic fluid or solution can comprise a single phase or a plurality of phases. For example, the heterocyclic fluid or solution can comprise a liquid phase or a mist for spraying the mist into a gas stream for forming a mixed phase stream before flowing into and / or contacting the mixed phase stream with the MOF sorbent or the spent MOF. In an embodiment, the method can comprise a step of removing excess heterocyclic fluid and / or unreacted ligands from the spent MOF, thereby forming the MOF sorbent. The excess heterocyclic fluid or solution can be recovered for reuse. In an embodiment, the method can further comprise at least one of the steps of washing and drying the MOF sorbent before reinstalling the MOF sorbent into the sorptive separator. In one aspect, a concentration of aromatic heterocyclic molecules or compounds in the heterocyclic fluid or solution is in a range of 0.03 moles per liter (M) to 0.67 M. Referring to Fig. 7c, contactor 83 comprising spent MOF and plurality of passages 84 is configured with plurality of passages 84 in a substantially horizontal position and submerged in heterocyclic solution 81 in an enclosure 80. Heterocyclic solution 81 flows and diffuses into plurality of passages 84 and in contact with contactor 83 and the spent MOF. In one aspect, the heterocyclic fluid or solution can comprise at least one of 1 ,2,4-triazole, 3-amino-1 ,2,4-triazole, 3-methyl-1 ,2,4-triazole, and other 1 ,2,4-triazole derivatives.

[0080] A method of treating or repairing a MOF sorbent, for at least one of adding ligands to the MOF sorbent, changing the crystalline structure of the MOF sorbent, increasing a porosity of the MOF sorbent, and increasing a sorptive capacity of the MOF sorbent, wherein the MOF sorbent can comprise a less than desirable quantity or substoichiometry quantity of ligands and / or a less than desirable crystalline structure. The less than desirable quantity of ligands and / or crystalline structure can be a result of but not limited to, for example, the MOF being subjected to a plurality of sorption-desorption cycles in a sorptive gas separation process further resulting in the removal and loss of at least a fraction of the aromatic heterocyclic molecules or compounds of the MOF sorbent, and can also be referred to as a spent MOF. The MOF sorbent can comprise an aromatic heterocyclic ligand; a metal ion or metal cluster; and an organic ligand or a carboxylate ligand, having a desired quantity of ligands and / or a substantially crystalline structure. The spent MOF can comprise the aromatic heterocyclic ligand; the metal ion or metal cluster; and the organic ligand or the carboxylate ligand as the MOF sorbent, having a less than desired or a reduced quantity of ligands and a partially crystalline structure (or a partially amorphous structure). The method of treating or repairing a MOF sorbent can result in adding or reincorporating ligands by contacting aromatic heterocyclic molecules or compounds with the MOF sorbent. An aromatic heterocyclic fluid with aromatic heterocyclic molecules or compounds, in at least one of a liquid phase, a vapor phase, a mist, and a dispersion of solids in a liquid can be used to contact the MOF sorbent. The MOF and / or MOF sorbent can be CALF-20 or any MOF in the CALF-20 family.

[0081] In an embodiment, a method of treating or repairing a MOF sorbent can comprise the step of contacting an aromatic heterocyclic fluid with the MOF sorbent at a temperature in range of about 10°C to about 200°C, or preferably about 25°C to about 180°C, wherein the aromatic heterocyclic fluid comprise aromatic heterocyclic molecules or compounds and at least one of a solvent and a carrier gas. In an embodiment, the method can further comprise the step of washing the MOF sorbent and / or removing at least one of excess aromatic heterocyclic fluid and unreacted ligands. In one aspect, the heterocyclic fluid or solution can comprise at least one of 1,2,4-triazole, 3-amino-1 ,2,4-triazole, 3-methyl-1 ,2,4-triazole, and other 1 ,2,4-triazole derivatives.

[0082] In aspects, at least one of, the MOF sorbent can be supported on and / or in a porous support, the porous support comprising a wetted surface area equal to or greater than about 200 m2 / m3; and the aromatic heterocyclic fluid can be at least one of a vapor phase, a liquid phase, a mixed gaseous and liquid phase, and a mist. In an embodiment, the method can further comprise prior to and / or during the contacting step, a step of controlling the temperature of the aromatic heterocyclic fluid and / or the MOF sorbent. In aspects, at least one of the contacting step can be for a duration in a range of about 1 minute to about 24 hours; performing the contacting step in an enclosure, and the contacting step can occur at a pressure equal to or greater than about atmospheric pressure or at solvothermal conditions. In embodiments, the method can further comprise a step of removing the MOF sorbent from the enclosure, prior to the washing.

[0083] In an embodiment, a MOF sorbent treatment system for repairing or treating a MOF sorbent, a self-supported composite, or a sorbent bed, can comprise:

[0084] (a) a repair void with at least one opening for conveying the MOF sorbent, the composite sorbent or the sorbent bed into the repair void;

[0085] (b) a support for the MOF sorbent, the composite sorbent or the sorbent bed within the repair void;

[0086] (c) a fluidic connection to a regeneration fluid source and the repair void, and

[0087] (d) a means of controlling the temperature of the repair void and / or contents in the repair void.

[0088] In aspects, the MOF sorbent, the self-supporting composite, and the sorbent bed can comprise a MOF with an aromatic heterocyclic ligand; a metal ion or a metal cluster; and an organic ligand or a carboxylate ligand.

[0089] In one aspect, the repair void can be defined by the sorbent bed. In another aspect, the means of controlling temperature of the repair void can be a heat exchanger or heating device for adjusting the temperature of a regeneration fluid flowing through the repair void.

[0090] In an embodiment, the system can further comprise a heating device for heating or increasing a temperature of the repair void and the self-supported composite, or one or more sorbent beds. In an aspect, the temperature can be within a range of about 20°C to about 200°C, or preferably about 25°C to about 180°C. In one aspect, the heating device can be at least one of a resistive heater, a convection heater, a radiative heater for example, by electromagnetic waves or infrared, a radio wave or an induction heater, and a microwave (electromagnetic radiation) heater.

[0091] In an embodiment, the heating device can be formed by the sorbent bed or the self-supporting composite. For example, the self-supported composite can comprise an electrically conductive porous substrate such as a non-woven carbon fiber fabric that becomes a resistive heating element once installed within the repair void or an enclosure of the repair void.

[0092] In an embodiment, a MOF sorbent treatment system for treating or repairing a MOF sorbent can comprise:

[0093] (a) a heterocyclic fluid source, for supplying a heterocyclic fluid comprising an aromatic heterocyclic molecule or compound;

[0094] (b) an enclosure for confining at least a portion of the MOF sorbent and at least a portion of the heterocyclic fluid, and

[0095] (c) a heat source for supplying heat to the heterocyclic fluid, wherein heterocyclic fluid is at least periodically in contact with the MOF sorbent and the heating source is thermally connected to the heterocyclic fluid.

[0096] In aspects, the system can further comprise at least one controller for controlling a temperature of the heterocyclic fluid. In one aspect, the MOF sorbent can comprise an organic ligand or a carboxylate ligand, a metal ion or metal cluster, and a heterocyclic ligand. In another aspect, the MOF sorbent is CALF-20 or part of the CALF-20 family or CALF-20 wherein the 1 ,2,4-triazolate of CALF-20 can be replaced by at least one of 3-amino-1 ,2,4-triazolate or 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3, 5-diamino-1 ,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate

[0097] In another aspect, the heterocyclic fluid or solution can comprise at least one of 1,2,4-triazole, 3-amino-1,2,4-triazole, 3-methyl-1,2,4-triazole, and other 1,2,4-triazole derivatives.

[0098] In an embodiment, the heterocyclic fluid source can be fluidly connected to the enclosure to supply the heterocyclic fluid.

[0099] In another aspect, the heat source can be at least one of a resistive heater, a convection heater, a radiative heater for example, by electromagnetic waves or infrared, a radio wave or an induction heater, and a microwave (electromagnetic radiation) heater. In one aspect, the heat source can heat and / or maintain a temperature of at least one of the heterocyclic fluid to a temperature within a range of about 20°C to about 200°C, or preferably about 25°C to about 180°C.

[0100] In an embodiment, a method for extending the life of a MOF sorbent by at least one of reducing a rate of degradation of a sorptive capacity, maintaining a sorptive capacity, and / or repairing a sorptive capacity of the MOF sorbent is disclosed. The method can enable the repair of the MOF sorbent comprising an organic ligand or a carboxylate ligand; a metal ion or metal cluster; and a heterocyclic ligand in a sorptive separator as part of a sorptive separation process. The method can reduce sublimination and loss of the heterocyclic ligand from the MOF sorbent as a result of exposure to steam, water, and / or heat. In one aspect, the heterocyclic ligand that is susceptible to sublimation, and / or loss due to exposure to steam, water, and / or heat, an aromatic heterocyclic molecule or compound is added substantially continuously or intermittently to a sorptive separator, sorbent bed, and the MOF sorbent during a sorptive process in order reduce the chemical potential between the gas phase and the solid phase when the solid is heated. A more advantageous method could be to cyclically or at periodical intervals repair the damage due to heterocyclic ligand stripping by the regeneration stream. This concept can work for both membrane separators and sorptive separators, the high temperature stripping mechanism of the ligand from the MOF is less likely for applications operating at modest temperatures, for example, less than about 100°C.

[0101] In an embodiment, a sorptive gas separation process, the process can comprise the steps of:

[0102] (a) admitting a feed stream comprising a first component into a sorptive separator comprising a MOF sorbent having a metal ion or metal cluster, an organic ligand or carboxylate ligand and a heterocyclic ligand and contacting the feed stream with the MOF sorbent;

[0103] (b) sorbing the first component from the feed stream in and / or on the MOF sorbent, producing a first product stream depleted in the first component relative to the feed stream, and recovering a first product stream from the sorptive separator;

[0104] (c) desorbing at least a fraction of the first component from the MOF sorbent, forming a second product stream enriched in the first component relative to the first stream, and recovering a second product stream from the sorptive separator, and (d) admitting an aromatic heterocyclic molecule or compound into the sorptive separator.

[0105] In an embodiment, the process can further comprise adding the aromatic heterocyclic molecule or compound to the feed stream for admitting into the sorptive separator. In one aspect, the aromatic heterocyclic molecule or compound can be at a concentration equal to or greater than 0.5 ppm by weight, or equal to or greater than 1 ppm by weight of the feed stream.

[0106] In an embodiment, the process can further comprise in step (c) of admitting a regeneration stream comprising steam into the sorptive separator, contacting the regeneration stream with the MOF sorbent, sorbing steam on the MOF, and producing the second product stream enriched in the first component relative to the feed stream, and recovering the second product stream from the sorptive separator.

[0107] In an embodiment, the process can further comprise after step (c), admitting a conditioning stream into the sorptive separator, contacting the conditioning stream with the MOF sorbent, desorbing steam from the MOF sorbent, and producing a third product stream enriched in steam relative to the conditioning stream. In one aspect, the conditioning stream can comprise a partial pressure of steam of about half of the partial pressure of steam in the feed stream.

[0108] In an embodiment, the process can further comprise adding the aromatic heterocyclic molecule or compound to at least one of the regeneration stream and the conditioning stream for admitting into the sorptive separator. In one aspect, the aromatic heterocyclic molecule or compound can be at a concentration equal to or greater than 0.5 ppm by weight of the regeneration stream or the conditioning stream, or equal to or greater than 1 ppm by weight of the regeneration stream or the conditioning stream.

[0109] In an embodiment, the process can further comprise repeating steps (a) to (c).

[0110] In aspects of the process, at least one of: the aromatic heterocyclic molecule or compound is in a fluid or a solution comprising the aromatic heterocyclic molecule or compound, and a carrier gas, for example, steam, nitrogen, helium, air, other suitable inert gas, or combinations thereof, or a solvent, for example, at least one of water, and any other suitable organic solvents or combinations thereof; the aromatic heterocyclic molecule or compound is in a form of at least one of a liquid, a mist, and a vapor; the first component is, for example, an acid gas or carbon dioxide; the multicomponent gas stream is a combustion gas, a flue gas, ambient air, atmospheric air, a process gas stream, and / or a biogas stream; the MOF sorbent comprises an aromatic heterocyclic ligand; a metal ion or a metal cluster; and an organic ligand or a carboxylate ligand, and the MOF sorbent is CALF-20 or part of the CALF-20 family.

[0111] In aspects, at least one of the feed stream can be a multi-component gas stream, the multi-component gas stream and / or the feed stream can have a first component and a second component, the first component can be carbon dioxide, and the second component can be nitrogen.

[0112] In an embodiment, a sorptive gas separation process, the process can comprise the steps of:

[0113] (a) admitting a feed stream into a sorptive separator comprising at least one MOF sorbent, sorbing at least a portion of the first component from the feed stream on and / or in the at least one MOF sorbent to form a first product stream depleted in the first component relative to the feed stream, and recovering the first product stream from the sorptive separator;

[0114] (b) desorbing at least a portion of the first component from the at least one MOF sorbent to form a second product stream enriched in the first component relative to the feed stream, and recovering the second product stream from the sorptive separator, and

[0115] (c) admitting an aromatic heterocyclic molecule or compound into the sorptive separator, contacting the aromatic heterocyclic molecule or compound with the at least one MOF sorbent.

[0116] In further embodiments, the process can further comprise at least one of:

[0117] • during step (c) admitting the aromatic heterocyclic molecule or compound into the sorptive separator at a temperature in a temperature range of about 20°C to about 200°C, or preferably about 25°C to about 180°C;

[0118] • during step (c) admitting the aromatic heterocyclic molecule or compound into the sorptive separator for a duration of equal to or greater than 10 minutes, equal to or greater than 30 minutes, or equal to or than 1 hour;

[0119] • recovering the aromatic heterocyclic molecule or compound from the sorptive separator;

[0120] • recovering the aromatic heterocyclic molecule or compound from the sorptive separator from at least one of the first product stream and the second product stream;

[0121] • performing steps (a) and (b) sequentially to form at least part of a cycle and the cycle is repeated while periodically performing step (c) separate from steps (a) and (b), or periodically performing step (c) during or combined with step (a) or step (b);

[0122] • performing steps (a), (b), and (c) sequentially to form at least part of a cycle and the cycle is repeated;

[0123] • repeating sorbing-desorbing cycles or step (a) and step (b) and reducing a sorptive capacity of the at least one MOF sorbent for the first component relative to a sorptive capacity of the at least one MOF sorbent before start of the process, and during step (c) increasing a sorptive capacity of the at least one MOF sorbent for the first component;

[0124] • during step (a), admitting the aromatic heterocyclic molecule or compound into the feed stream;

[0125] • during step (b) admitting a regeneration stream comprising steam into the sorptive separator for desorbing the first component from the at least one MOF sorbent, producing a second product stream enriched in the first component relative to the feed stream, and recovering the second product stream from the sorptive separator;

[0126] • prior to or during step (b) and (c), admitting the aromatic heterocyclic molecule or compound into the regeneration stream;

[0127] • after step (b), admitting a conditioning stream into the sorptive separator, contacting the conditioning stream with the MOF sorbent, desorbing steam from the MOF sorbent, and producing a third product stream enriched in steam relative to the conditioning stream;

[0128] • the conditioning stream can comprise a partial pressure of steam of about half of the partial pressure of steam in the feed stream;

[0129] • the admitting the aromatic heterocyclic molecule or compound into the sorptive separator is by admitting the aromatic heterocyclic molecule or compound into at least one of the feed stream, the regeneration stream, and the conditioning stream;

[0130] • the aromatic heterocyclic molecule or compound can be at a concentration of equal to or greater than 0.5 parts per million by weight (ppm wt) or equal to or greater than 1 ppm wt, of the at least one of the feed stream, the regeneration stream, and the conditioning stream;

[0131] • adding or admitting the aromatic heterocyclic molecule or compound into at least one of the feed stream, the regeneration stream, and the conditioning stream at a concentration of equal to or greater than 0.5 parts per million by weight (ppm wt) or equal to or greater than 1 ppm wt, of the at least one the feed stream, the regeneration stream, and the conditioning stream,

[0132] • wherein the sorptive separator comprise a first end and a second end and during step (a) admitting the feed stream into the sorptive separator is performed by admitting the feed stream into the first end of the sorptive separator and during step (c) admitting the aromatic heterocyclic molecule or compound into the sorptive separator is performed by admitting the aromatic heterocyclic molecule or compound into the second end of the sorptive separator,

[0133] • wherein the sorptive separator comprise a first end and a second end and during step (a) admitting the feed stream into the sorptive separator is performed by admitting the feed stream into the first end of the sorptive separator, during step (b) admitting a steam stream into the sorptive separator for desorbing the first component from the at least one MOF sorbent is performed by admitting the steam stream into the second end of the sorptive separator, and during step (c) admitting the aromatic heterocyclic molecule or compound into the sorptive separator is performed by admitting the aromatic heterocyclic molecule or compound into the second end of the sorptive separator, and

[0134] • during step (c) a pressure in the sorptive separator can be at equal to or greater than about atmospheric pressure.

[0135] In aspects of the process, at least one of: the aromatic heterocyclic molecule or compound is in a fluid or a solution comprising the aromatic heterocyclic molecule or compound, and a carrier gas, for example, steam, nitrogen, helium, air, other suitable inert gas, or combinations thereof, or a solvent, for example, at least one of water, and any other suitable organic solvents or combinations thereof; the aromatic heterocyclic molecule or compound is in a form of at least one of a liquid, a mist, and a vapor; the first component is, for example, an acid gas or carbon dioxide; the feed stream can be a multi-component gas stream; the multicomponent gas stream and / or the feed stream can have a first component and a second component; the first component can be carbon dioxide; the second component can be nitrogen; the multicomponent gas stream can be at least one of a combustion gas, a flue gas, ambient air, atmospheric air, a process gas stream, and a biogas stream; the MOF sorbent comprises an aromatic heterocyclic ligand; a metal ion or metal cluster, and an organic ligand or a carboxylate ligand, and the MOF sorbent is CALF-20 or part of the CALF-20 family or CALF-20 wherein the 1 ,2,4-triazolate of CALF-20 can be replaced by at least one of 3-amino-1 ,2,4-triazolate or 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1,2,4-triazolate, 3, 5-diamino-1 ,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, 3,5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate.

[0136] In an embodiment, a sorptive gas separation system can comprise:

[0137] (a) a sorptive separator with at least a first vessel, a second vessel, and a third vessel, wherein the first vessel, the second vessel, and the third vessel further comprise a composite sorbent or sorbent bed, wherein the composite sorbent or sorbent bed having a MOF sorbent with a metal ion or a metal cluster; an organic ligand or a carboxylate ligand; and a heterocyclic ligand;

[0138] (b) at least one selector valve fluidly connected to the first vessel, the second vessel, and the third vessel;

[0139] (c) a feed stream source fluidly connected to the at least one selector valve for supplying a feed stream;

[0140] (d) a steam stream source fluidly connected to the at least one selector valve for supplying a steam stream;

[0141] (e) a heterocyclic fluid source fluidly connected to the at least one selector valve for supplying a heterocyclic fluid stream comprising aromatic heterocyclic molecules or compounds,

[0142] wherein the at least one selector valve fluidly connects each of the first vessel, the second vessel, and the third vessel periodically to the feed stream source, the steam stream source, and the heterocyclic fluid source.

[0143] In an embodiment, the first vessel, the second vessel, and the third vessel can be stationary. In another embodiment, one of the first vessel, the second vessel, and the third vessel can be fluidly connected to one of the feed stream source, the steam stream source, and the heterocyclic fluid source via the at least one selector valve at a given time. In another embodiment, one of the first vessel, the second vessel, and the third vessel can be fluidly connected to receive both the steam stream and the heterocyclic fluid stream at about a same time wherein the steam stream and the heterocyclic fluid stream can be combined prior to admitting into the vessels or the steam stream and the heterocyclic fluid stream can be admitting into the vessels separately. In an embodiment, the first vessel, the second vessel, and the third vessel can be fluidly connected to a recovery device for recovering the aromatic heterocyclic molecules or compounds from the first vessel, the second vessel and the third vessel. In aspects, the steam stream source can be a regeneration stream source, and the steam stream can be a regeneration stream.

[0144] In an embodiment, the at least one selector valve can switch between the feed stream source and the steam stream source in equal to or less than 2 minutes, or equal to or less than 1 minute. In an embodiment, the at least one selector valve can fluidly connect at least one of the first vessel, the second vessel, and the third vessel with the heterocyclic fluid source for a duration of equal to or greater than 10 minutes, equal to or greater than 30 minutes, or equal to or greater than 1 hour. In one aspect, the heterocyclic fluid source can supply at least one of 1 ,2,4-triazole, 3-amino-1 ,2,4-triazole, 3-methyl-1 ,2,4-triazole, and other 1 ,2,4-triazole derivatives. In one aspect, the heterocyclic fluid stream can comprise at least one of 1 ,2,4-triazole, 3-amino-1 ,2,4-triazole, 3-methyl-1 ,2,4-triazole, and other 1 ,2,4-triazole derivatives.

[0145] The steam stream and the heterocyclic fluid stream can be fluidically connected, enabling the mixing of these two streams before entering each sorption vessels within the sorptive separator.

[0146] Excess of aromatic heterocyclic molecules or compounds in an effluent stream of the sorptive separator can be directed to a recovery device where the aromatic heterocyclic molecule or compound can be condensed and recovered from the effluent stream for reuse.

[0147] Fig. 8a is a schematic diagram of a sorptive separation system according to an embodiment of the invention illustrating a feed stream source 60 and a regeneration stream source 63, for example, a steam stream source, which are fluidly connected to supply a sorbent bed 1 in a counter-flow direction relative to each other. Sorbent bed 1 comprising a MOF with an organic ligand or a carboxylate ligand; a metal ion or metal cluster, and a heterocyclic ligand. Feed stream source 60 is fluidly connected to supply a feed stream 61 into sorbent bed 1 via a first end 4. A first product stream 62 can be recovered via second end 5 of sorbent bed 1. A regeneration stream source 63 is fluidly connected to supply a regeneration stream 64 into sorbent bed 1 via a second end 5. A second product stream 65 can be recovered via first end 4 of sorbent bed 1. A heterocyclic fluid source 66 is fluidly connected to supply a heterocyclic fluid 67 into sorbent bed 1 via second end 5. A heterocyclic excess stream 68 can be recovered via first end 4 of sorbent bed 1. In embodiments, the heterocyclic fluid can comprise aromatic heterocyclic molecules or compounds and at least one of a solvent and a carrier gas. The heterocyclic fluid can be at least one of a liquid, a vapor, a liquid and a vapor, or a mist. The solvent can be at least one of water, a suitable organic based solvent, or combinations thereof. The regeneration stream can be, for example, steam. The carrier gas can be steam, nitrogen, helium, air, other suitable inert gas, or combinations thereof. A solvent source and a carrier gas source are not shown in Fig. 8a.

[0148] Fig. 8b is a schematic diagram of a sorptive separation system according to an embodiment of the invention illustrating a feed stream source 60 and a regeneration stream source 63 are fluidly connected to supply a sorbent bed 1 in a coflow direction relative to each other. Sorbent bed 1 comprising a MOF with an organic ligand or carboxylate ligand; a metal ion or metal cluster, and a heterocyclic ligand. Feed stream source 60 is fluidly connected to supply a feed stream 61 into sorbent bed 1 via a first end 4. A first product stream 62 can be recovered via second end 5 of sorbent bed 1. Regeneration stream source 63 is fluidly connected to supply a regeneration stream 64 into sorbent bed 1 via first end 4. A second product stream 65 can be recovered via second end 5 of sorbent bed 1. A heterocyclic fluid source 66 is fluidly connected to supply a heterocyclic fluid 67 into sorbent bed 1 via first end 4. A heterocyclic excess stream 68 can be recovered via second end 5 of sorbent bed 1. In embodiments, the heterocyclic fluid comprises aromatic heterocyclic molecules or compounds and at least one of a solvent and a carrier gas. The heterocyclic fluid can be at least one of a liquid, a vapour, a liquid and a vapour, or a mist. The solvent can be at least one of water, a suitable organic based solvent, or combinations thereof. The regeneration stream can be, for example, steam. The carrier gas can be steam, nitrogen, helium, air, other suitable inert gas, or combinations thereof. A solvent source and a carrier gas source are not shown in Fig. 8b. In an embodiment, a sorptive gas separation system, the system can comprise:

[0149] (a) a feed stream source for providing a multi-component gas feed stream as a feed stream having at least a first component and a second component;

[0150] (b) a sorptive separator having at least one fluid passage and a MOF sorbent, wherein the MOF sorbent can be at least periodically fluidly connected to the feed stream source via the at least one fluid passage for receiving the feed stream, and (c) a heterocyclic fluid source, wherein the MOF sorbent can be at least periodically fluidly connected to the heterocyclic fluid source via the at least one fluid passage for receiving aromatic heterocyclic molecules or compounds.

[0151] In aspects of the sorptive gas separation system,

[0152] • the MOF sorbent can comprise an aromatic heterocyclic ligand, a metal ion or metal cluster, and an organic ligand or a carboxylate ligand in the form of a crystalline metal-organic framework;

[0153] • the sorptive separator can comprise a first end and a second end, and the feed stream source can be fluidly connected to the first end of the sorptive separator, the second end of the sorptive separator can be fluidly connected to the atmosphere, the first product stream conduit can be fluidly connected to the second end of the sorptive separator, the regeneration stream source can be fluidly connected to the second end of the sorptive separator and the second product stream conduit can be fluidly connected to the first end of the sorptive separator, the heterocyclic fluid source can be fluidly connected to the second end of the sorptive separator and the third product stream conduit can be fluidly connected to the first end of the sorptive separator,

[0154] • wherein the regeneration stream source is a steam source;

[0155] • wherein the first component is carbon dioxide, and

[0156] • wherein the second component is nitrogen. In embodiments, the system can further comprise at least one of

[0157] • a regeneration stream source, wherein the MOF sorbent can be at least periodically fluidly connected to the regeneration stream source via the at least one fluid passage for receiving a regeneration stream and to a second product stream conduit via the at least one fluid passage for recovering a second product stream from the sorptive separator;

[0158] • a conditioning stream source, wherein the MOF sorbent can be at least periodically fluidly connected to the conditioning stream source via the at least one fluid passage for receiving a conditioning stream and to a third product stream conduit via the at least one fluid passage for recovering a third product stream from the sorptive separator,

[0159] • wherein the sorptive separator and / or at least one fluid passage can be at least periodically fluidly connected to at least one of a first product stream conduit for recovering a first product stream from the sorptive separator, a second product stream conduit for recovering a second product stream from the sorptive separator, and a third product stream conduit for recovering a third product stream from the sorptive separator,

[0160] • wherein the sorptive separator and / or at least one fluid passage can be at least periodically fluidly connected to the at least one of the first product stream conduit, the second product stream conduit and a third product stream conduit for recovering the aromatic heterocyclic molecules or compounds from the sorptive separator;

[0161] • a nozzle fluidly connected to the heterocyclic fluid source and the at least one fluid passage for creating a mist;

[0162] • a carrier gas source, for example, a source of steam, nitrogen, helium, air, other suitable inert gas, or combinations thereof, fluidly connected to the heterocyclic fluid source and the at least one fluid passage;

[0163] • a heater fluidly and / or thermally connected to at least one of the heterocyclic fluid source, heterocyclic fluid, and sorptive separator for increasing and / or maintaining a temperature of the heterocyclic fluid to a temperature in a range of about 20°C to about 200°C or about 25°C to about 180°C; • the heterocyclic fluid source can supply at least one of aromatic a heterocyclic molecule or compound, 1,2,4-triazole, 3-amino-1,2,4-triazole, 3-methyl- 1.2.4-triazole, and other 1 ,2,4-triazole derivatives; and

[0164] • the heterocyclic fluid source can comprise at least one of an aromatic heterocyclic molecule or compound, 1,2,4-triazole, 3-amino-1 ,2,4-triazole, 3-methyl-1 ,2,4-triazole, and other 1,2,4-triazole derivatives.

[0165] Examples:

[0166] Example 1: CALF-20 [Zn2Tz20x] composite sorbent sheet preparation: CALF-20 was prepared according to the method described in International Publication No. WO 2022 / 175927 A1, washed and dried. CALF-20 was mixed with binders and additives, forming a first sample comprising greater than 80% by weight of CALF-20 and the rest being the binders and additives.

[0167] Example 2: A sorbent bed comprising Example 1 was placed into a sorptive separator for accelerated aging using a 20 second cycle with an adsorbing step using a feed stream with 15% CO2 blended in moist air, a regenerating step using a steam stream, and a conditioning step using a dried air stream, for 600,000 cycles over about 3500 hours thereby forming a second sample. Profiles of CO2 sorption capacity versus distance from the steam end of the sorbent bed after aging are presented in Fig. 1.

[0168] Example 3: The second sample was cut into multiple segments and a section at about 2% of the length of the sorptive separator from an end of the sorptive separator where steam is admitted during a desorbing step, was characterized by Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS).

[0169] Example 4: The degraded sample in the form of a laminate sheet or second sample from Example 3 weighing about 9 grams (g) was placed in a sealed vessel having 4 liters (L) of a 1 :2 methanol: water solution with 1 ,2,4-triazole (0.67M). The laminate was submerged and heated at 50°C for 24 hours. The laminate was removed and soaked in fresh methanol for 24 hours. Periodically the solvent was replenished to wash off excess 1.2.4-triazole. After washing, the laminate was heated to 110°C for several hours to dry and / or activate the material. Repaired composite sorbents were also characterized by SEM and EDS. The comparison of fresh, spent and repaired MOF sorbent samples are presented in Figs. 2a, 2b, 2c, and Figs. 3a, 3b, 3c, 3d, 3e, 3f.

[0170] Fig. 3a is a SEM image of a fresh MOF sorbent sample at 10,000X magnification.

[0171] Fig. 3b is a SEM image of the fresh MOF sorbent sample shown in Fig. 3a but at 10,000X magnification.

[0172] Fig. 3c is a SEM image of a spent MOF sorbent sample at 1,000X magnification.

[0173] Fig. 3d is a SEM image of the spent MOF sorbent sample shown in Fig. 3c but at 1 ,000X magnification.

[0174] Fig. 3e is a SEM image of a repaired MOF sorbent sample at 1,000X magnification.

[0175] Fig. 3f is a SEM image of the repaired MOF sorbent sample shown in Fig.

[0176] 3e but at 1 ,000X magnification.

[0177]

[0178] Table 1 : EDS elemental composition of the surface of a composite sorbent before and after repair

[0179] Table 1 provides the average wt% for detected elements at the surface of the composite coupons after sample aging and after repair by exposure to a liquid solution as in Example 4. The amount of nitrogen measured by EDS increased sharply from 3.67% to 19.11% after composite repair indicating the incorporation of triazole into the solid coupon. Example 5: Another coupon sample from Example 2 was placed into a hydrothermal pressure vessel suspended above a 15mL solution of a 1:2 ratio of a methanol and water mixture comprising 0.67M 1 ,2,4-triazole and heated to 180°C for 24 hours.

[0180] Fig. 4 presents an X-Ray diffraction diagram for fresh, spent and repaired MOF samples. A fresh sample is shown as a pattern 40. A spend sample is shown as a pattern 41. A repaired sample is shown as a pattern 42.

[0181] Example 6: The sorption capacity for CO2 was measured for various composite sorbent samples as follows: multiple coupons in the shape of 5mm disks were cut from a larger stock and placed in a thermogravimetric analysis (TGA) pan, the sample was first dried at 110°C under nitrogen, then cooled to 50°C under nitrogen before being exposed to a mixture of 15% CO2 with the balance of nitrogen. The sample weight was recorded and the weight change converted into an amount of CO2 adsorbed (or CO2 capacity) in cubic centimeters (cc) at standard pressure and temperature (STP) per gram (g) of the composite sorbent sample.

[0182] Figs. 5a and 5b shows thermogravimetric analysis (TGA) test results for Example 6. The y-axis represents weight of the sample in percentage. The y-axis represents time in minutes. Fig. 5a shows the TGA profile for a spent sample before repair with a CO2 capacity of 23.6 cc / g. Fig. 5b shows the TGA profile for a spent sample after repair with a CO2 capacity of 38.4 cc / g. Fig. 5b indicates the adsorption kinetics for the sample after repair are similar to the adsorption kinetics for the sample before repair.

[0183] Table 2 presents sorption capacity values for different samples as measured in Example 6. For the first three after repair samples shown in Table 2, the sorption capacity for CO2 is similar to that of a fresh sample, which can indicate substantially full recovery of the sorption capacity for CO2may be achieved after repair regardless of the degree of degradation of the spent sample.

[0184]

[0185] Table 2: before and after composite sorbent repair, CO2 sorption capacity at 50°C with 15% CO2

[0186] The last two samples in the table were repaired through a vapor phase exposure of the composite to triazole. In this case the repair recovered about 80% of the fresh sorbent capacity. These results may validate the concept of gas phase mediated MOF sorbent repair.

[0187] Fig. 6 is a graph showing the sorptive capacity of CO2 or water at 0%, 10%, and 20% RH of a repaired sample compared to a fresh sample. The y-axis represents a sorptive capacity as a percentage by weight. The x-axis represents relative humidity (RH) as a percentage. The tests were conducted using a gas stream with 15% CO2 at 50°C. The sorptive capacity of CO2 for a repaired sample is shown as a plot 60. The sorptive capacity of CO2 for a fresh sample is shown as a plot 61. The sorptive capacity of water for the repaired sample is shown as a plot 62. The sorptive capacity of water for the fresh sample is shown as a plot 63. Fig. 6 indicates the adsorption kinetics and CCh / water binary performance are similar between the repaired sample and the fresh sample.

Claims

CLAIMS:

1. A method for forming, treating, or repairing a metal-organic framework (MOF) sorbent, the method comprising;at least one of contacting and reacting a MOF precursor with an aromatic heterocyclic fluid comprising an aromatic heterocyclic molecule or compound,wherein the MOF precursor further comprises at least one of a metal ion, or a metal cluster, and an organic ligand or a carboxylate ligand.

2. The method of claim 1 , wherein the MOF precursor further comprises a sub-stoichiometric quantity of heterocyclic ligands.

3. The method of claim 1 or 2, wherein the MOF precursor is amorphous.

4. The method of claim 1 , wherein the MOF sorbent further comprises an aromatic heterocyclic ligand, a metal ion or a metal cluster, and an organic ligand or a carboxylate ligand.

5. The method of claim 1 to 4, wherein the metal ion or the metal cluster comprises zinc.

6. The method of claim 1 to 4, wherein the aromatic heterocyclic molecule or compound is the same aromatic heterocyclic molecule or compound in the aromatic heterocyclic fluid and the aromatic heterocyclic ligand.

7. The method of claim 1 to 4, wherein the MOF sorbent further comprises at least one of: a crystalline structure and a porous crystalline structure.

8. The method of claim 1 to 4, wherein the MOF sorbent is in and / or on a substrate which is porous.

9. The method of claim 8, wherein the substrate further comprises a wetted surface area equal to or greater than 200 square meters per cubic meter.

10. The method of any one of claims 1 to 9, wherein at least one of the MOF sorbent and the MOF precursor is CALF-20, a MOF in the CALF-20 family, or CALF-20 wherein the 1 ,2,4-triazolate is replaced by at least one of 3-amino-1 ,2,4-triazolate or 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3,5-diamino-1 ,2,4-triazolate, 3,5-dimethyl-1 ,2,4-triazolate, 3,5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate.

11. The method of any one of claims 1 to 10, further comprising controlling a temperature of the at least one of contacting and reacting a MOF precursor with an aromatic heterocyclic fluid step.

12. The method of claim 11 , wherein the temperature is equal to or greater than 50°C.

13. The method of any one of claims 1 to 12, further comprising prior to the at least one of contacting and reacting a MOF precursor, combining the aromatic heterocyclic fluid with a solvent or a carrier gas.

14. The method of claim 13, wherein at least one of: the solvent is at least one of methanol, water, an organic-based solvent, and an alcohol-based solvent; and the carrier gas is at least one of steam, nitrogen, helium, and air.

15. The method of claims 1 to 14, wherein the aromatic heterocyclic fluid is in a liquid phase, a vapor phase, a mist, or a dispersion of solids in a liquid.

16. The method of claim 13 or 14, wherein the solvent further comprises methanol with a concentration of equal to or greater than 1% by volume of the solvent.

17. The method of any one of claims 1 to 16, further comprising conducting the at least one of contacting and reacting a MOF precursor with an aromatic heterocyclic fluid for a duration in a range of 1 minute to 24 hours.

18. The method of any one of claims 1 to 17, further comprising conducting the at least one of contacting and reacting a MOF precursor with an aromatic heterocyclic fluid at a pressure equal to or greater than atmospheric pressure or at solvothermal conditions.

19. The method of any one of claims 1 to 18, wherein the MOF precursor is formed by subjecting the MOF sorbent or the MOF precursor to at least one of steam, heat, and sorption-desorption cycles.

20. The method of any one of claims 1 to 19, further comprising at least one of: placing the MOF precursor over the heterocyclic fluid, diffusing the heterocyclic fluid into the MOF precursor, and submerging the MOF precursor into a bath of a heterocyclic fluid.

21. A sorptive gas separation process comprising:(a) admitting a feed stream into a sorptive separator comprising at least one MOF sorbent, sorbing at least a portion of a first component from the feed stream on and / or in the at least one MOF sorbent to form a first product stream depleted in the first component relative to the feed stream, and recovering the first product stream from the sorptive separator;(b) desorbing at least a portion of the first component from the at least one MOF sorbent to form a second product stream enriched in the first component relative to the feed stream, and recovering the second product stream from the sorptive separator, and(c) admitting an aromatic heterocyclic molecule or compound into the sorptive separator, contacting the aromatic heterocyclic molecule or compound with the at least one MOF sorbent.

22. The process of claim 21 , wherein the MOF sorbent comprises an aromatic heterocyclic ligand, a metal ion or metal cluster, and an organic ligand or a carboxylate ligand.

23. The process of claim 21 , wherein the MOF sorbent is CALF-20 or CALF-20 wherein the 1 ,2,4-triazolate of CALF-20 is replaced by at least one of 3-amino-1 ,2,4-triazolate or 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3, 5-diamino-1 ,2,4-triazolate, 3,5-dimethyl-1,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate.

24. The process of any one of claims 21 to 23, further comprising during step (b), admitting a regeneration stream comprising steam into the sorptive separator.

25. The process of claim 24, further comprising after step (b) admitting a conditioning stream into the sorptive separator.

26. The process of any one of claims 21 to 25, wherein the admitting the aromatic heterocyclic molecule or compound into the sorptive separator is by admitting the aromatic heterocyclic molecule or compound into at least one of the feed stream, the regeneration stream, and the conditioning stream.

27. The process of claim 26, further comprising admitting the aromatic heterocyclic molecule or compound at a concentration of equal to or greater than 0.5 parts per million by weight of the at least one of the feed stream, the regeneration stream, and the conditioning stream.

28. The process of any one of claims 21 to 27, further comprising admitting the aromatic heterocyclic molecule or compound into the sorptive separator at a temperature in a temperature range of 20°C to 200°C.

29. A sorptive gas separation system, the system comprising:(a) a feed stream source for providing a feed stream having at least a first component and a second component;(b) a sorptive separator having at least one fluid passage and a MOF sorbent, wherein the MOF sorbent is at least periodically fluidly connected to the feed stream source for receiving the feed stream, and(c) a heterocyclic fluid source, wherein the MOF sorbent is at least periodically fluidly connected to the heterocyclic fluid source for receiving an aromatic heterocyclic molecule or compound therefrom.

30. The system of claim 29, wherein the MOF sorbent comprise an aromatic heterocyclic ligand, a metal ion or metal cluster, and an organic ligand or a carboxylate ligand.

31. The system of claim 30, wherein the MOF sorbent is CALF-20 or CALF-20 wherein the 1 ,2,4-triazolate of CALF-20 is replaced by at least one of 3-amino-1 ,2,4-triazolate or 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3, 5-diamino-1 ,2,4-triazolate, 3,5-dimethyl-1,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate.

32. The system of claim 29, wherein the heterocyclic fluid source is a source of at least one of an aromatic heterocyclic molecule or compound, 1 ,2,4-triazole, 3-amino-1 ,2,4-triazole, 3-methyl-1 ,2,4-triazole, and other 1 ,2,4-triazole derivatives.

33. The system of claim 29, wherein at least one of the first component is carbon dioxide, and the second component is nitrogen.

34. A MOF treatment system for treating or repairing a MOF sorbent, the system comprising:(a) a heterocyclic fluid source, for supplying a heterocyclic fluid comprising an aromatic heterocyclic molecule or compound;(b) an enclosure for confining at least a portion of the MOF sorbent and at least a portion of the heterocyclic fluid, and(c) a heat source for supplying heat to the heterocyclic fluid, wherein the heterocyclic fluid is at least periodically in contact with the MOF sorbent and the heating source is thermally connected to the heterocyclic fluid.

35. The system of claim 34, wherein the heterocyclic fluid source is fluidly connected to the enclosure.

36. The system of claim 34, wherein the heterocyclic fluid comprise at least one of 1,2,4-triazole, 3-amino-1,2,4-triazole, 3-methyl-1,2,4-triazole, and other 1.2.4-triazole derivatives.

37. The system of claim 34, wherein the MOF sorbent comprise an organic ligand or a carboxylate ligand, a metal ion or metal cluster, and a heterocyclic ligand.

38. The system of claim 34, wherein the MOF sorbent is CALF-20 or CALF-20 wherein the 1 ,2,4-triazolate of CALF-20 is replaced by at least one of 3-amino- 1.2.4-triazolate or 3-methyl-1 ,2,4-triazolate, 3-chloro-1 ,2,4-triazolate, 3-bromo-1 ,2,4-triazolate, 3, 5-diamino-1 ,2,4-triazolate, 3,5-dimethyl-1,2,4-triazolate, 3, 5-dimethyl-1 ,2,4-triazolate, and 3-amino,5-methyl-1 ,2,4-triazolate.

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