Metal-organic frameworks for removing a variety of liquid phase compounds and methods of use and manufacture thereof

Abstract

The present application relates to metal-organic frameworks for removing a variety of liquid phase compounds and methods of use and manufacture thereof. The present invention relates to coordination metal-organic frameworks (MOFs) for removing both anionic species and cationic species from a liquid or liquid stream. The present invention also provides methods of placing MOFs on a substrate to form a product comprising the MOF, which can be used to remove certain species from a given fluid. The MOF can be a Zr-based MOF (e.g., NU-1000) for removing certain anions, such as oxygen-containing anions, or have attached thiosulfonyl-thiol (-SO2-S-R2-SH, where R2 is an alkyl group) ligands for complexing with certain cationic species in addition to anions. The substrate can be any substrate to which a given MOF can be attached, including inert polypropylene polymeric resin beads, macroscopic fabrics (e.g., screen materials or screen filters), and molecular fabrics.

Description

[0001] This application is a divisional application of parent application number 201980071121.6. The parent application was filed on August 25, 2019; the invention is entitled "Metal-organic framework for removing various liquid-phase compounds and its use and manufacturing method". Technical Field

[0002] This invention and its embodiments relate to the removal of a given chemical substance from a liquid. Specifically, this invention and its embodiments relate to the use of metal-organic frameworks (MOFs) having specific properties suitable for adsorbing certain anions (e.g., oxoanions) and having ligands attached for the removal of certain cations (e.g., lead and mercury) from a liquid or liquid stream (e.g., an industrial liquid stream). This invention and its embodiments also relate to methods of attaching these MOFs to certain substrates and using those substrates. Specifically, this invention and its embodiments relate to methods of attaching MOFs to various substrates, such as polypropylene beads, macro-fabrics, and molecular fabrics, for the removal of certain chemical substances from a liquid. Background Technology

[0003] The challenges for nuclear facilities include the removal of several impurities that significantly contribute to or drive the radiation dose, the generation of radioactive waste, environmental effluent waste issues, and material degradation problems. Similarly, fossil-based power generation facilities face challenges such as regulatory discharge requirements for wastewater from flue gas desulfurization and from scrubbing towers, furnace-side washing, and boiler cleaning operations, as well as groundwater remediation requirements due to coal pile wastewater and ash pond leachate. Current technologies (e.g., ion exchange) lack the ability to remove these impurities to the required levels due to factors related to capture mechanisms and competition with other impurities.

[0004] Recently developed chelating media offer organometallic ligands modified on the resin backbone (at positions that would otherwise contain cation exchange groups), which significantly improve the removal of analytes such as cations like cobalt. Unfortunately, such ligands cannot accommodate the large geometry of oxyanions from substances such as selenium found in the subject water stream. For example, ion exchange and adsorption techniques are commonly used to capture chemical impurities in water streams. However, these techniques have several significant drawbacks. They are nonspecific (i.e., they will capture many different substances to some extent), subject to competition (i.e., higher concentrations of substances will dominate), and reversible (i.e., captured substances will be released when water conditions change).

[0005] Selenium removal from water is of particular concern. Selenium is a naturally occurring element, and low concentrations are essential for human health. However, among all essential elements, selenium has the narrowest range between dietary deficiency (<40 μg / day) and toxicity (>400 μg / day). Selenium enters our waterways through many different sources, such as agricultural runoff, mining, industrial production, and flue gas desulfurization processes. Due to the narrow range between deficiency and toxicity, monitoring and controlling the amount of bioavailable selenium in drinking water is crucial. The U.S. Environmental Protection Agency recognizes the hazards of selenium and has set a maximum permissible level of 50 ppb for selenium in drinking water. However, in recent proposals, regulations have been set to reduce selenium emission requirements to 14 ppb, and then further to 10 ppb. This allows for the attainment of purity levels that many current flue gas desulfurization wastewater treatment facilities cannot achieve without exceeding the typical operating methods of ion exchange or adsorption engineering units.

[0006] Selenium can exist in both organic and inorganic forms, but forms such as selenite (SeO3) are more common. 2- ) and selenate (SeO4) 2- The high solubility and therefore bioavailability of inorganic substances such as selenite and selenate make these anions a primary focus of remediation technologies. Numerous technologies have been explored for the removal of selenite and selenate from water, including the use of vertical flow wetlands and bioreactors; however, high start-up costs and size requirements limit their application. Another approach investigated involves the absorption and removal of unwanted inorganic selenium using adsorption media. Iron oxides (hematite, goethite, and ferrihydrite) have been extensively studied as potential adsorbents for selenite and selenate in aqueous solutions. These iron-based materials have very low surface areas, meaning that much material is wasted due to a lack of available adsorption sites. Iron oxides also tend to effectively remove selenite due to the formation of inner-layer complexes between selenite anions and the iron oxide surface, while selenate removal is insufficient due to only weak outer-layer interactions.

[0007] Additionally, it may be advantageous to remove certain liquid-phase cations from certain industrial liquid streams. Some cations found in industrial wastewater streams may be environmental pollutants or harmful to industrial processes, thus necessitating their removal from the corresponding liquid streams. For example, it may be necessary to remove certain cations from wastewater and other liquid process streams associated with power generation processes, such as fossil and nuclear process coolants and industrial cooling water.

[0008] For example, lead is believed to be associated with intergranular corrosion and stress corrosion cracking (SCR) in steam generator tubes in nuclear power plants. Lead, highly soluble, is ubiquitous in nuclear power plant environments, originating from welding, brazing, lubrication, and the extensive use of lead materials for radiation shielding, leading to lead contamination in steam generator feedwater. Lead is known to accelerate SCR in several different alloys used in steam generator tubes (e.g., Alloys 600, 800, and 690). Furthermore, nuclear power companies are seeking to extend service life to 80 years, and the new PWR advanced light water reactor design under construction will use steam generator tubes with 690TT (heat-treated) and 800NG (nuclear-grade) tubes. In caustic solutions, lead causes 690TT and 800NG tubes to be actually more susceptible to SCR than 600MA (rolled and annealed) tubes, resulting in severe SCR aging. Considering the significant cost of addressing these harmful effects of lead, reducing the amount of lead in contact with steam generator tubes can reduce the risk of lead SCR.

[0009] Ion exchange is a method for removing cations from liquid streams. For example, ion exchange is used for the aqueous purification of lead (Pb) cations from typical fossil and nuclear process coolants or industrial cooling water streams. 2+ However, it is difficult (if not impossible) to achieve removal that reduces the concentration of cations in a liquid stream to ultra-low levels (e.g., parts per billion or less). In some cases, removal using ion exchange media is limited due to equilibrium leakage (i.e., reversal of the absorption reaction). However, to meet technical specifications or emission regulations, cations must be removed to such ultra-low levels. Furthermore, it should be understood that current U.S. Environmental Protection Regulations regarding lead limits in drinking water are extremely low, for example, as low as 10 ppb.

[0010] However, achieving such lead removal using typical adsorption media is difficult. Even when ionic interactions are as dominant as in ion exchange, the analyte accumulates within the pores of the adsorption medium as it adsorbs the analyte from the incoming liquid stream. Consequently, the concentration gradient favoring analyte transport reverses and begins to drive the analyte back into the lower concentration inflow stream. This process is often referred to as “equilibrium leakage” from the absorbent medium, and in the case of an ion exchange bed, it occurs near the effluent end of the bed. Therefore, the lower the desired stream concentration, the more difficult it becomes to achieve analyte absorption.

[0011] Additionally, there are cases where a given liquid or liquid stream contains ionic impurities containing both anionic and cationic charges. For example, amphoteric compounds are commonly found in industrial processes and environmental remediation, and these compounds can exhibit a positive or negative charge bias depending on the environment in which they are found. In the nuclear industry, steam generator water is such an environment. Depending on temperature and local acidity, elemental lead in steam generator water can be found in a state of both cationic (+2) and oxygen-containing anionic charge formation, both of which are solvated by water molecules.

[0012] Therefore, a novel technology is needed to effectively and efficiently remove specific impurities, such as certain anions and cations, from water and other liquid streams (e.g., industrial aqueous streams). Such a technology is needed to remove these impurities in the presence of competing substances, or potentially to target the removal of competing substances while effectively reducing the removal efficiency of the target substance. Furthermore, a technology is needed to specifically target the capture of such impurities and minimize any reversibility or release from the capture, thereby retaining them with higher binding energies. Specifically, different types of structural media are needed to specifically address the removal of low levels of specific substances with sufficiently high binding energies to maintain near-irreversible absorption while reducing the concentration of the analyte and simultaneously increasing the concentration of the competitor.

[0013] Therefore, it is advantageous to provide a novel technology that effectively and efficiently removes specific impurities from water and other liquid streams (e.g., other industrial aqueous streams), including both certain liquid-phase anions (e.g., oxygen-containing anions, including selenium-containing anions) and liquid-phase cations (e.g., lead and mercury). Specifically, it is advantageous to provide a compound and a method for removing both oxygen-containing anions (including selenium-containing anions) and liquid-phase cations (e.g., cationic lead and mercury).

[0014] More specifically, it is advantageous to provide compounds that reduce the concentration of certain substances (e.g., aqueous oxygenated anions of selenium) to already low levels and possess sufficiently high binding energies to maintain near-irreversible absorption, while removing lead from the liquid stream to ultra-low levels with minimal or no equilibrium leakage. It is also advantageous to provide compounds that provide high absorption capacity for certain liquid-phase cations, such as lead and mercury cations, thereby reducing the liquid-phase concentration of those cations to ultra-low levels with minimal or no equilibrium leakage.

[0015] It is also advantageous to provide a method that utilizes such a compound to remove both liquid-phase anions (e.g., oxyanions, including oxyanions such as selenium) and liquid-phase cations (e.g., lead and mercury) from water and other liquid streams (e.g., other industrial aqueous streams). For example, it is advantageous to provide such a compound and method to remove both liquid-phase anions (e.g., oxyanions, including oxyanions such as selenium) and liquid-phase cations (e.g., lead and mercury) from liquid streams in fossil fuel or nuclear power plants. Specifically, it is advantageous to provide a method that utilizes such a compound to reduce the concentration of liquid-phase anions (e.g., oxyanions, including oxyanions such as selenium) and liquid-phase cations (e.g., cationic lead and mercury) in a liquid stream to ppb levels or below, with minimal or no equilibrium leakage.

[0016] However, in some cases, the high cost of manufacturing such MOFs makes their use very expensive. Therefore, there is a need for methods to produce and supply MOFs in a way that reduces their usage costs. Summary of the Invention

[0017] This invention relates primarily to metal-organic frameworks (MOFs) for removing various liquid-phase compounds (particularly both anionic and cationic substances) from liquids or liquid streams. In some embodiments, the MOF is a Zr-based MOF, such as NU-1000, which has the ability to complex or adsorb certain anionic substances and has linking ligands for complexing with certain cationic substances. Removable anionic substances include, for example, oxyanions, such as selenium oxyanions, including selenite (SeO3). 2- ) and selenate (SeO4) 2- Antimony oxoanions, including Sb[III] (antimony) or Sb[V] (antimony) redox states; and lead oxoanions, including Pb[II] or Pb[IV] redox states, such as Pb(OH)6. 2- Pb(OH)6 4- PbO3 2- and PbO2 2- Removable cationic substances include, for example, divalent lead (Pb). 2+ ) or mercury (Hg 2+ And similar cations. Therefore, the MOF of the present invention captures or removes both oxygen-containing anions and cations from a given liquid or liquid stream. In general use, the method of the present invention involves contacting an MOF having linking ligands for complexing with cations with a given liquid or liquid stream, adsorbing various oxygen-containing anions, and complexing various cations, thereby removing both from the liquid or liquid stream. It should be understood that any combination of anions and cations present in a given liquid stream can be removed using an MOF having ligands for complexing with cations.

[0018] The general formula for both the MOF and the ligand structure is R1-SO2-S-R2-SH, where R1 is a MOF to which the ligand (-SO2-S-R2-SH) can be attached, and where R2 is an alkyl group of ethyl or propyl. In some embodiments, the present invention provides compounds having the formula R1-SO2-S-R2-SH for complexing with both oxyanions and liquid-phase cations, wherein R1 comprises a zirconium-based metal-organic framework having a side group attached to an organic linker, and R2 comprises an alkyl group. In some embodiments, the side group may be a benzyl group.

[0019] In one embodiment, the MOF has the molecular formula Zr6(μ3O)4(μ3OH)4(OH)4(H2O)4(TBAPy)2, wherein TBAPy is 1,3,6,8-tetra(terebenzoic acid)pyrene (referred to as NU-1000). Without being theoretically limited, the preferred mechanism for the complexation of oxyanions by the MOF is adsorption. In one embodiment, the MOF adsorbs oxyanions via nodal absorption through the zirconium oxide / hydroxide node portion of the MOF.

[0020] The ligands attached to the MOF for complexation with cationic substances are thiosulfonyl-thiols (-SO2-S-R2-SH, where R2 is an alkyl group) ligands, also known as thio-alkyl-sulfonyl-thiols ligands. This ligand can be attached to the MOF by any method known in the art, as long as it does not significantly interfere with the MOF's ability to adsorb specific anions. In some embodiments, the ligand can be attached to the MOF via a side group. In some embodiments, the side group is attached to a linking group of the MOF. It should be understood that multiple side groups can be used, each attached to a separate linking group of the MOF. It should also be understood that the sulfonyl group attached to the MOF allows the thioalkyl group to be attached to the sulfonyl group on the MOF via nucleophilic attack. Therefore, any side group to which the sulfonyl group can be attached and which itself can be nucleophilically attacked can be used to attach the ligands of the present invention to the MOF. In some embodiments, the side group is a sulfonyl (i.e., -SO2-) functional group attached to a benzyl group attached to the MOF.

[0021] In another embodiment, the present invention provides a method for reducing the concentration of oxyanions and cations from a liquid stream, the method comprising contacting a liquid stream containing oxyanions and cations with a compound having the formula R1-SO2-S-R2-SH, wherein R1 comprises a zirconium-based metal-organic framework having side groups attached to an organic linking group, and R2 comprises an alkyl group; complexing the oxyanions with the zirconium-based metal-organic framework to reduce the concentration of oxyanions in the liquid stream; and complexing the cations with the compound to reduce the concentration of cations in the liquid stream. In another embodiment, the side group is a benzyl group, and wherein the oxyanions are complexed with nodes of the zirconium-based metal-organic framework, and wherein the cations are complexed with the thiosulfonyl moiety of the compound and the terminal thiol of the compound to form a cyclic geometry.

[0022] The ability of MOFs with linked ligands to reduce the concentration of certain anions (e.g., oxoanions) and certain cations (e.g., lead) in water offers numerous benefits. Removing oxoanions from water streams such as industrial wastewater provides more environmentally acceptable water, particularly in the removal of selenate and selenite, since selenium can be toxic at certain levels in drinking water. Removing cations (such as lead and mercury) from liquid streams, considering, for example, drinking water restrictions, can provide health and environmental benefits. Additionally, removing lead from fossil fuel or nuclear power plant streams can have several beneficial effects, including reducing stress corrosion cracking in certain materials in which the liquid stream comes into contact.

[0023] The present invention also describes a method for attaching certain MOFs to a substrate to form a product containing the MOF, the product of which can be used in a variety of ways depending on the specific MOF attached to the substrate. Therefore, it should be understood that, in order to attach to a substrate, a specific MOF with specific properties can be selected, such as affinity for a specific substance to be removed from a given fluid. The substrate can be any substrate to which a given MOF can be attached, and the form and shape of the substrate can be selected based on its end use. For example, the structure or shape of the substrate can be selected to allow the use of the selected MOF in a given environment (e.g., a given industrial process or a given piece of equipment) and to provide appropriate MOF exposure in that environment, such as MOF exposure to a given fluid in a given process or piece of equipment.

[0024] It should be understood that an MOF can be any of the MOFs described herein. For example, in one embodiment, an MOF can be one capable of removing certain chemicals from a given fluid. For example, an MOF can be one capable of or configured to remove certain liquid-phase substances from a given liquid or liquid stream. In some embodiments, the MOF is a Zr-based MOF, such as NU-1000, for removing certain anions, such as oxoanions, from a liquid or liquid stream. In other embodiments, the MOF is a Zr-based MOF, such as NU-1000, configured to remove certain cations from the liquid or liquid stream described herein. In some embodiments, the MOF is a Zr-based MOF, such as NU-1000, configured to remove both certain anions (e.g., certain oxoanions) and certain cations from the liquid or liquid stream described herein. In other embodiments, the MOF is a Zr-based MOF, such as NU-1000, which has the ability to complex or adsorb certain anionic substances and has linking ligands for complexing with certain cationic substances described herein.

[0025] In one embodiment, the substrate can be any inert substrate to which the MOF can be attached. For example, the substrate can be inert polypropylene polymer resin beads, macro-fabric (e.g., screen material or screen filter), molecular fabric, or any other three-dimensional shaped substrate.

[0026] In one embodiment, a MOF, including any MOFs described herein, such as Zr-based MOFs like NU-1000, with or without ligands for complexing with certain cationic substances described herein, may be attached to an inert substrate, such as polypropylene polymer resin beads, macro-fabrics (e.g., sieve materials or sieve filters), or molecular fabrics. In one embodiment for attaching the MOF, the substrate is first subjected to atomic layer deposition of a metal oxide (e.g., alumina, titanium oxide, or zinc oxide) onto its surface. The MOF may be individually attached to CTAB in solution and then bonded to the substrate having the metal oxide. This attaches the MOF to the substrate and produces a commercial product consisting of a substrate with the attached MOF. In another embodiment for attaching the MOF to the substrate, the MOF may be attached to β-CD in solution and then bonded to the substrate. This attaches the MOF to the substrate via β-CD and produces a commercial product consisting of a substrate with the attached MOF.

[0027] It should be understood that the substrate containing the MOF can be used in many ways, depending on the MOF selected for attachment to a given substrate, and the substrate can be a commercial product. As mentioned above, in some embodiments, the MOF can be a MOF capable of removing certain chemicals from a given fluid. For example, the MOF can be a Zr-based MOF, such as NU-1000, constructed for removing certain anions (e.g., certain oxyanions) and certain cations from a liquid or liquid stream. Specifically, NU-1000 is based on zirconium (Zr) and has the molecular formula Zr6(μ3-O)4(μ3OH)4(OH)4(H2O)4(TBAPy)2, where TBAPy is 1,3,6,8-tetra(para-benzoic acid)pyrene. NU-1000 can be used on substrates to remove selenium oxyanions, including selenite (SeO3). 2- ) and selenate (SeO4) 2- ); and antimony oxyanions, including Sb[III] (antimony) or Sb[V] (antimony) redox states of oxyanions; and lead oxyanions, including Pb[II] or Pb[IV] redox states of oxyanions, such as Pb(OH)6 2- Pb(OH)6 4- PbO3 2- and PbO2 2- Furthermore, adding certain ligands to these MOFs can remove certain cationic substances, such as divalent lead (Pb). 2+ ) or mercury (Hg 2+ And similar cations. Therefore, such MOFs with linking ligands can provide the ability to simultaneously remove both cationic and anionic substances from a given liquid or liquid stream (e.g., power plant coolant or waste stream, including nuclear power plant liquid streams). In other embodiments, the MOF can be a Zr-based MOF for removing certain chemicals, such as water, from gas streams or air (including ambient air). Such MOFs may include MOF-801, 801-P, 802, 805, 806, 808, 812, and 841. In other embodiments, the substrate containing the MOF, which may be a commercial product, may be a Zr-based MOF, such as NU-1000, having the ability to complex or adsorb certain anionic substances and having linking ligands for complexing with certain cationic substances described herein.

[0028] It should be understood that this invention offers numerous benefits. As mentioned above, the ability to select a given MOF based on its intended use or needs, combined with the ability to select or adjust the design of the substrate to which the MOF is attached, provides ample flexibility in the overall design of products incorporating MOFs. Furthermore, placing the MOF on an inert substrate, such as multiple chemically inert polypropylene beads, macro-fabricated fabrics, or molecular fabrics, provides a platform or mechanism for exposing the MOF to a given fluid of interest and removing the target substance from that fluid. Assuming the MOF can absorb a given amount of a specific substance or the capacity of multiple substances from a fluid, placing the MOF on a given substrate allows for control over its structure or shape to ensure proper exposure to the fluid in a given environment, enabling the use of lower quantities of MOF and thus significantly reducing the cost of MOFs used in any given process. Essentially, transplanting expensive MOF particles onto inexpensive structures allows the use of MOFs in existing industrial structures without the need to produce enough MOF particles to fill the entire structure. For example, in some embodiments, the structure of the substrate can provide the necessary surface exposure of the MOF to achieve the desired results with that MOF without using a relatively large amount of pure MOF. In fact, coating structures with thin MOF particle layers, such as polypropylene beads, macro-fabrics (e.g., screen filters), or molecular fabrics, can reduce costs significantly compared to using MOF particles without any structural support. Such cost savings will enable the widespread use of MOF particles in many industrial processes, including both fossil fuel plants and nuclear power plants.

[0029] For example, placing MOFs on a support structure provides the ability to effectively contact a given liquid being treated with the MOF, allowing for the absorption of chemicals to be removed by the MOF. Coating inert beads (e.g., polypropylene beads) with MOFs enables a high surface area contact between the MOFs and any liquid flow in which the beads are arranged. Therefore, placing MOFs on the surface of polypropylene beads provides the MOF particles with the ability to bind compounds in the liquid flow as the liquid flow is filtered through the MOF structure. Furthermore, the use of an inert structure coated with MOFs (e.g., polypropylene beads) allows for liquid contact between the MOFs and the flowing liquid flow without convective separation from other MOF particles.

[0030] It should also be understood that the methods of the present invention for attaching MOFs to specific substrates and producing commercial products similarly offer many benefits. As mentioned above, the ability to select a given MOF based on its intended use or needs, combined with the ability to select or adjust the design of the substrate to which the MOF is attached, provides a wide range of options in the overall design of products incorporating MOFs. Furthermore, placing MOFs on inert substrates, such as multiple chemically inert polypropylene beads, macro-fabrics, or molecular fabrics, provides a platform or mechanism for exposing the MOF to a given fluid of interest and removing the target substance from that fluid. Assuming the MOF absorbs a given amount of a specific substance or the capacity of multiple substances from the fluid, placing the MOF on a given substrate allows control over its structure or shape to properly expose the MOF to the fluid in a given environment, enabling the use of lower quantities of MOF, thereby significantly reducing the cost of MOFs used in any given process. Essentially, transplanting expensive MOF particles onto inexpensive structures allows the use of MOFs in existing industrial structures without the need to produce enough MOF particles to fill the entire structure. For example, in some embodiments, the structure of the substrate can provide the necessary surface exposure of the MOF to achieve the desired results with that MOF without using a relatively large amount of pure MOF. In fact, coating structures with thin MOF particle layers, such as polypropylene beads, macro-fabrics (e.g., screen filters), or molecular fabrics, can reduce costs significantly compared to using MOF particles without any structural support. Such cost savings will enable the widespread use of MOF particles in many industrial processes, including both fossil fuel plants and nuclear power plants.

[0031] For example, placing MOFs on a support structure provides the ability to effectively contact a given liquid being treated with the MOF, allowing for the absorption of chemicals to be removed by the MOF. Coating inert beads (e.g., polypropylene beads) with MOFs enables a high surface area contact between the MOFs and any liquid flow in which the beads are arranged. Therefore, placing MOFs on the surface of polypropylene beads provides the MOF particles with the ability to bind compounds in the liquid flow as the liquid flow is filtered through the MOF structure. Furthermore, the use of an inert structure coated with MOFs (e.g., polypropylene beads) allows for liquid contact between the MOFs and the flowing liquid flow without convective separation from other MOF particles. Attached Figure Description

[0032] Figure 1 This illustrates a metal-organic framework (MOF) according to one embodiment of the present invention;

[0033] Figure 2 Show a specific MOF, NU-1000;

[0034] Figure 3 show Figure 2The structural features of the NU-1000MOF;

[0035] Figure 4A shows the structure of the NU-1000 with prominent hexagonal hole size and the structure of the Zr6 node;

[0036] Figure 4B The structure of UiO-66 with prominent octahedral hole size and Zr6 node structure are shown;

[0037] Figure 5 A bar graph showing the number of selenate or selenite molecules adsorbed at each node in a series of Zr-based MOFs;

[0038] Figure 6 To display the absorption kinetics curves of selenate and selenite in NU-1000, UiO66-NH2 and UiO66-(NH2)2;

[0039] Figure 7 This flowchart shows a summary of the screening process for the adsorption of selenate and selenite in Zr-based MOFs.

[0040] Figure 8A Showing the DRIFTS spectra of the synthesized NU-1000 (lower trace) and after the adsorption of two molecules, selenite (middle trace) and selenate (upper trace);

[0041] Figure 8B Display range from 4000-2000cm -1 Magnified DRIFTS spectrum;

[0042] Figure 8C This shows the possible binding modes of selenate (or selenite) with the nodes of NU-1000;

[0043] Figure 9A Display the calculated difference pair distribution functions (PDFs) for NU-1000 loaded with selenite and selenate.

[0044] Figure 9B The experimental differential PDFs for NU-1000 loaded with selenite and selenate are shown, with only the peaks at the matching η2μ2 binding distances displayed.

[0045] Figure 10 The absorption-time of selenate and selenite in NU-1000 (2 mg) at low concentrations and an initial concentration of 1000 ppb (as Se);

[0046] Figure 11 The absorption-time of selenate and selenite in NU-1000 (2 mg) at low concentrations and 40°C and an initial concentration of 1000 ppb (as Se) was shown.

[0047] Figure 12 The absorption-time of selenate and selenite in NU-1000 (2 mg) at low concentrations and pH 6 and an initial concentration of 1000 ppb (as Se) is shown.

[0048] Figure 13A -E shows the amount (q)-time of adsorption at each node of NU-1000 at different selenate and selenite concentrations, where the amount of adsorption is expressed as milligram weight of all oxygen-containing anions normalized to the gram weight of bare NU-1000 MOF.

[0049] Figures 14A-C show the Langmuir plots (linear, type I) of selenite and selenate adsorption on NU-1000, with the amount adsorbed as the weight of all oxygen-containing anions.

[0050] Figure 15A Showing the powder X-ray diffraction pattern of the synthesized NU-1000 compared to NU-1000 after adsorption of selenite or selenate;

[0051] Figure 15B Shows the nitrogen adsorption isotherm of synthetic NU-1000 compared to NU-1000 after adsorption of selenite or selenate.

[0052] Figure 16A -C shows the absorption of selenate and selenite as a function of time using 2 mg NU-1000 and 10 mL of aqueous solution containing 100 ppb Se and (a) 100 ppb sulfur S with (b) 500 ppb S and (c) 1000 ppb S (as sulfate).

[0053] Figure 17A -B shows the absorption of Sb(OH)6- over time as an example of absorption per node;

[0054] Figure 18 Show the Langmuir fit from the Sb[V] adsorption isotherm in Figure 17;

[0055] Figure 19 Showing powder X-ray diffraction patterns of NU-1000 and NU-1000 with Sb(OH)6-;

[0056] Figure 20 Showing the nitrogen isotherms of NU-1000 and NU-1000 with Sb(OH)6-;

[0057] Figure 21 This invention shows a general compound for removing cations from liquids according to one embodiment;

[0058] Figure 22This invention illustrates a compound for removing cations from a liquid according to one embodiment;

[0059] Figure 23 This invention illustrates another compound for removing cations from a liquid according to another embodiment;

[0060] Figure 24 An embodiment of the present invention is shown. Figure 22 The interaction between the compound and lead cations; and

[0061] Figure 25 An embodiment of the present invention is shown. Figure 23 The interaction between the compound and lead cations. Detailed Implementation

[0062] The invention is described more fully below with reference to the accompanying drawings. Although the invention has been described in conjunction with specific embodiments, it should be understood that the invention is applicable to a wide variety of applications, and the description herein is intended to cover substitutions, modifications, and equivalents within the spirit and scope of the invention and the claims. Therefore, the following description is exemplary in that it describes multiple embodiments (e.g., by using the terms “preferred,” “for example,” or “in one embodiment”), but this description should not be considered as limiting or elaborating on the only embodiments of the invention, as the invention includes other embodiments not specifically described herein. Furthermore, throughout this description, the terms “invention,” “this invention,” “implementation,” and similar terms are used broadly and are not intended to imply that the invention is necessary for or limited to any particular aspect described, or that such a description is the only way the invention can be carried out or used. It should be understood that some of the drawings are not drawn to scale and are not intended to represent any particular three-dimensional conformation of the compounds or complexes shown.

[0063] This invention primarily relates to metal-organic frameworks (MOFs) for removing various liquid-phase compounds (particularly both anionic and cationic substances) from liquids or liquid streams. In some embodiments, the MOF has linked ligands, enabling the MOF itself to complex or adsorb certain anionic substances, and the linked ligands to complex with certain cationic substances. Removable anionic substances include, for example, oxyanions, such as selenium oxyanions, including selenite (SeO3). 2- ) and selenate (SeO4) 2- Antimony oxoanions, including Sb[III] (antimony) or Sb[V] (antimony) redox states; and lead oxoanions, including Pb[II] or Pb[IV] redox states, such as Pb(OH)6. 2- Pb(OH)6 4- PbO3 2-and PbO2 2- Removable cationic substances include, for example, divalent lead (Pb). 2+ ) or mercury (Hg 2+ And similar cations. Therefore, the MOF of the present invention captures or removes both oxygen-containing anions and cations from a given liquid or liquid stream. In general use, the method of the present invention involves contacting an MOF having linking ligands for complexing with cations with a given liquid or liquid stream, adsorbing various oxygen-containing anions, and complexing various cations, thereby removing both from the liquid or liquid stream. It should be understood that any combination of anions and cations present in a given liquid stream can be removed using an MOF having ligands for complexing with cations.

[0064] It should also be understood that MOFs with ligands that complex with cationic substances can remove amphoteric compounds, or those compounds whose environment is found to be positively or negatively biased. For example, lead oxyanions and lead cations can be adsorbed by MOFs with appropriately functionalized ligands. As described below, lead oxyanions in solution can be adsorbed by the NU-1000 zirconium MOF via a nodal absorption mechanism. Simultaneously, if lead cation-absorbing ligands are available on the inner surface of the MOF cavity, cationic lead can be removed within the MOF cavity, while the anionic oxygen-anion form can be removed at the zirconium nodal structure.

[0065] In some embodiments, the MOF is a Zr-based MOF, such as NU-1000. In one embodiment, the MOF has the molecular formula Zr6(μ3O)4(μ3OH)4(OH)4(H2O)4(TBAPy)2, wherein TBAPy is 1,3,6,8-tetra(terebenzoic acid)pyrene (referred to as NU-1000). Without being theoretically limited, the preferred mechanism for the complexation of oxyanions by the MOF is adsorption. In one embodiment, the MOF adsorbs oxyanions via nodal absorption through the zirconium oxide / hydroxide node portion of the MOF.

[0066] The ligand attached to the MOF for complexation with cationic substances is a thiosulfonyl-thiol (-SO2-S-R2-SH, where R2 is an alkyl group) ligand, also known as a thio-alkyl-sulfonyl-thiol ligand. This ligand can be attached to the MOF via a side group. In some embodiments, the side group is attached to a linking group of the MOF. It should be understood that multiple side groups can be used, each attached to a separate linking group of the MOF. It should also be understood that the sulfonyl group attached to the MOF allows the thioalkyl group to attach to the sulfonyl group on the MOF via nucleophilic attack. Therefore, any side group to which the sulfonyl group can attach and which itself can be nucleophilically attacked can be used to attach the ligand of the present invention to the MOF. In some embodiments, the side group can be a side benzyl group.

[0067] It should be understood that suitable side groups can be attached to the linking group moiety of a MOF using solvent-assisted linker exchange (SALE) or solvent-assisted ligand binding (SALI) (see, for example, P. Deria, W. Bury, J. Thuupp and OK Farha, “Versatile Functionalization of the NU-1000 Platform by Solvent-Assisted Ligand Incorporation”, Chem. Commun. 2014, 50, 1965-1068; and P. Deria, J. E. Mondloch, O. Karagiardi, W. Bury, J. Thuupp and OK Farha, “Beyond Post-Synthesis Modification: Evolution of Metal-Organic Frameworks via Building Block Replacement,” Chem. Soc. Rev. 2014, 43, 5896-5912). Therefore, side benzyl groups can be attached to various sites on the MOF, including the organic linking group moiety, using SALE or SALI. In one embodiment, a side benzyl group (e.g., [MOF]-HC=C-CH-phenyl) can be generated by attaching a phenyl group to the linking group portion of the MOF via a styrene bond. In some embodiments, the side benzyl group can be arranged within or inside the MOF structure, for example, in the middle or near the middle of the MOF, rather than arranging the side benzyl group adjacent to the pores of the MOF structure using SALI in some embodiments.

[0068] Therefore, the general formula for the MOF and ligand structure is R1-SO2-S-R2-SH, where R1 is a MOF having a suitable side group to which the ligand (-SO2-S-R2-SH) can be attached, and where R2 is an alkyl group of ethyl or propyl. In one embodiment, the ligand is attached to the MOF via a side group, which is a side benzyl group attached to the MOF by a sulfonyl (i.e., -SO2-) functional group.

[0069] Regarding the complexation of cationic substances with ligands linked to the MOF for complexation with the cationic substances, it should be understood that an important aspect of the ligand is the synthesis of the -SO2-S- bond, i.e., the SS bond between the thioalkyl and sulfonyl moieties. This provides ligands with a thiosulfonyl moiety and a terminal thiol moiety (-SH). As described below, cations (such as lead) complex with ligands via disulfide interactions, wherein the lead cation (Pb) 2+ It complexes with the thiosulfonyl moiety of the thiosulfate group and with the terminal thiol moiety (-SH), essentially "biting back" the lead cation (Pb).2+ This forms a five- or six-membered open-ring or cyclic geometry, depending on whether the R2 alkyl group is ethyl or propyl. The complexation of the cation with the ligand can also be termed ion interaction or chemisorption, which occurs through the positive charge on the cation and the electronegativity of the thiosulfonyl moiety and the terminal thiol moiety. Therefore, it should be understood that the ligands of the present invention can be used to complex cations other than lead. For example, with lead (Pb... 2+ Similar cations, such as cationic mercury, can be complexed in a similar manner.

[0070] Therefore, MOFs and ligands attached to the MOF for complexing with cationic substances provide a method or process for removing oxyanions and certain cationic substances (as described above) from a liquid stream, such as an industrial process liquid stream, including, for example, wastewater streams. Typically, contacting a liquid or liquid stream with an MOF having ligands attached for complexing with cationic substances causes adsorption of oxyanions, and the cationic substances are complexed by the MOF and thus removed from the liquid or liquid stream. The ability of MOFs (e.g., NU-1000) to reduce the concentration of oxyanions in water provides a more environmentally acceptable water stream. Furthermore, without being theoretically limited, it is believed that the ability to complex cationic substances via ligands attached to the MOF through the thio-sulfonyl moiety (thiol-sulfur group) and the anti-biting terminal thiol moiety provides the ability to remove large quantities of cations from a given liquid, resulting in the ability to obtain extremely low concentrations of a given cation within the liquid or liquid stream.

[0071] Figure 1 This illustrates a MOF according to one embodiment of the invention. MOFs are structurally diverse porous materials composed of metal nodes bridged by organic linking groups. MOFs consist of multifunctional organic linking groups and metal-based nodes interconnected by moderately strong coordination bonds. MOFs incorporating zirconium metal nodes are of interest in adsorbing or complexing analyte molecules from aqueous solutions due to their inherent stability over a wide pH range in water. This stability stems from strong Zr(IV)-O bonds, which also endow these frameworks with mechanical and thermal stability up to >500°C. MOFs in aqueous solutions are suitable candidates for pre-coated filter / softener applications or stand-alone packed tower separation applications, which can also be consistent with applications in containers already existing in a given plant, such as those used in nuclear power plants (e.g., containers already used for ion exchange) or flue gas desulfurization wastewater treatment facilities in fossil fuel power plants.

[0072] While MOFs can be used in such liquid flow applications due to their natural structure, the pressure required to penetrate a packed bed of such small particles (typically 75 to 1200 nm in size, with 5-micron crystallites formed from MOF particles) may exceed the available fluid-driven equipment. This means that it may be necessary to transfer the MOF particles onto other larger particle supports (larger resin particle sizes, typically 50 to 850 micron in diameter, in powder or bead form) so that the fluid can more easily penetrate the aggregates of support particles. Those skilled in the art should be able to devise various methods for contacting MOF particles onto suitable support particles such that the hydraulic permeability of the aggregates of such support particles, either in a columnar flow through such a bed of support particles or through a filter providing a porous surface coated with such support particles, is sufficiently high to provide the required fluid volume throughput. In this way, the MOF itself will be exposed to the analyte in the water flow, as the water flows around the support particles on which the MOF medium is attached, and thus the adsorption properties of the MOF will still be exhibited.

[0073] Figure 2 This describes a specific MOF, NU-1000. NU-1000 is a Zr-based MOF with the molecular formula Zr6(μ3-O)4(μ3OH)4(OH)4(H2O)4(TBAPy)2, where TBAPy is 1,3,6,8-tetra(para-benzoic acid)pyrene, which can be used as the MOF in this invention. The parent backbone nodes of this MOF consist of octahedral Zr6 clusters, which are capped by four μ3-OH and four μ3-O ligands. Eight of the twelve octahedral edges are connected to TBAPy units, while the remaining Zr coordination sites (after activation) are occupied by four terminal -OH and four terminal -OH2 ligands. The 3D structure can be described as 2D Kagome sheets linked by TBAPy ligands. Two of the four terminal -OH groups point towards the mesopore channels, while the remaining terminal hydroxyl groups are located in smaller pores between the Kagome sheets.

[0074] Figure 3 show Figure 2The structural features of the NU-1000 MOF are described. Other features of this MOF and its synthetic techniques are described in Mondloch, JE, W Bury, D Fairen-Jimenez, S Kwon, EJ DeMarco, MH Weston, AA Sarjeant, ST Nguyen, PC Stair, RQ Smurr, OK Farha and JT Hupp, “Vapor-Phase Metalation by Atomic Layer Deposition in a Metal-Organic Framework”, J. Am. Chem. Soc. (2013) 135, 10294-10297, which are incorporated herein by reference in their entirety. For example, the synthesis of the organic linking group of NU-1000 involves two steps: Suzuki coupling between 1,3,6,8-tetrabromopyrene and 4-(ethoxycarbonyl)phenyl)boronic acid, followed by hydrolysis of the resulting tetraester compound to give the tetracarboxylic acid linking group, 1,3,6,8-tetra(terebenzoic acid)-pyrene. To synthesize NU-1000, firstly, Zr6-cluster nodes were formed by reacting zirconium dichloride octahydrate with an excess of benzoic acid as a modifier in N,N-dimethylformamide at 80°C for 1 hour. After cooling the reaction mixture to room temperature, 0.2 equivalents of 1,3,6,8-tetra(p-benzoic acid)-pyrene linking groups were added, and the mixture was heated at 100°C for 24 hours to obtain benzoic acid-terminated NU-1000. To remove the benzoic acid ligands and expose the terminal -OH and -OH2 at the nodes, the MOF was activated with 8M HCl for 24 hours. It should also be understood that lower purity ZrOCl2·8H2O and HfOCl2·xH2O precursors reduce the manufacturing cost of NU-1000. For example, 99.99% purity ZrOCl2·8H2O and HfOCl2·xH2O cost approximately 400% more than 98% purity precursors. The structural features of this MOF are also described in Planas, N.; Mondloch, JE; Tussupbayev, S.; Borycz, J.; Gagliardi, L.; Hupp, JT; Farha, OK; Cramer, CJ. Defining the Proton Topology of the Zr6-Based Metal-Organic Framework NU-1000. J. Phys. Chem. Lett. 2014, 5, 3716-3723, which are incorporated herein by reference in their entirety.

[0075] Surprisingly, naked NU-1000 has been found to complex with selenium-containing oxyanions in aqueous solution, including selenite (SeO3-). 2-) and selenate (SeO4) 2- The results to date demonstrate that selenium-containing oxygen anions are bonded with significant strength to remove those anions to levels as low as 20 ppb, and even lower concentrations, such as 10 ppb and lower, 6 ppb and lower, and in other embodiments 2 ppb and lower, in a simple, continuous stirred tank environment with reasonable and relatively rapid time. The bonding of selenate and selenite anions is directly exposed to the zirconium nodes of the MOF without concern for ligand interactions with the MOF cavity. It should be understood that the ability to complex NU-1000 with selenite and selenate anions has been achieved without modifying the structure of NU-1000, for example, by using atomic layer deposition (ALD) to metallize NU-1000, by solvent-assisted linker exchange (SALE), and not by solvent-assisted ligand binding (SALI).

[0076] Specifically, the ability of a series of zirconium-based MOFs to adsorb and remove selenate and selenite anions from aqueous solutions was tested. The adsorption capacity and absorption time of the MOFs at different concentrations were also tested. Figure 7 A flowchart summarizing the screening process for selenate and selenite adsorption in Zr-based MOFs is provided. In this test, among all zirconium-based MOFs, NU-1000 exhibited the highest adsorption capacity and fastest absorption rate for both selenate and selenite.

[0077] Different adsorbent:adsorbate ratios were tested to understand how this ratio affected absorption. Samples of NU-1000 at concentrations of 2, 4, 6, and 8 mg were exposed to 10 mL of solution containing 1000 ppb Se (as SeO4). 2- or SeO3 2- The solution contained 98.3% or more of the SeO3 in all tested adsorbent-adsorbate ratios. 2- Adsorbed, leaving an average of 10-17 ppb in solution. Similarly, in all tests, the adsorbent:adsorbate ratio was 97.7% or more of SeO4 in solution. 2-Adsorbed, leaving an average of 20-23 ppb in solution. Typically, these experiments show that at these concentration levels, changing the adsorbent:adsorbate ratio by a factor of 4 has no significant effect on the total Se adsorbed from the solution. It should be noted that in Se absorption tests of the entire NU-1000, for example, studies conducted at pH 6 and similar batch studies using a starting concentration of 100 ppb Se instead of 1000 ppb, residual Se concentrations of less than 10 ppb (as low as 6 ppb and 2 ppb, respectively) have been observed when 2 mg of NU-1000 was exposed to 1000 ppb and 100 ppb Se, respectively. In such embodiments, the present invention can be used to reduce the total selenium concentration (i.e., the sum of all selenium substances) to less than 10 ppb, or an amount set for suitable drinking water standards. Therefore, in some embodiments, the present invention can reduce the total Se concentration in a given liquid or liquid stream by more than 90%, more than 94%, and more than 98%.

[0078] Figure 4A shows the structure of the NU-1000 with prominent hexagonal hole size and the structure of the Zr6 node. Figure 4B The structure of UiO-66 with prominent octahedral hole size and Zr6 node structure are shown. Screening is performed from NU-1000 (Fig. 4A) and UiO-66 ( Figure 4B The selenate and selenite adsorption capacities of metal-organic frameworks (MOFs) of the α and β groups (UiO-67) were investigated. For initial screening, two samples from each MOF were exposed to aqueous solutions of selenate (100 ppm Se) or selenite (100 ppm Se), respectively. After 72 hours of exposure, UiO-66 adsorbed 54% and 34% of the selenite and selenate present in their respective solutions, indicating anion exchange occurring both on and within the MOF. This suggests that despite the strong bridging properties of the OH groups in the UiO-66 nodes, Zr-bound hydroxides in the MOF can still be used to adsorb selenium-containing oxygen anions. Furthermore, Lewis / The presence of basic amine groups with UiO-66-(NH2)2 and UiO-66-NH2 appears to enhance anion exchange, indicating some of the highest selenate and selenite adsorption per Zr6- node in the studied MOFs. Figure 5 Unbound by theory, this may be a result of hydrogen bonding between the amine group and selenate and selenite anions, similar to hydrogen bonding units in a macrocyclic skeleton containing amines that have a high affinity for sulfate and selenate anions.

[0079] Figure 5 A bar graph showing the number of selenate or selenite molecules adsorbed at each node in a series of Zr-based MOFs. Figure 5The results showed that among the seven MOFs tested, NU-1000 achieved the highest absorbance for selenate and selenite in both gravimetric analysis and by node. It also removed these ions most completely from a 100 ppm Se test solution, namely 88% (SeO4). 2- ) and 90% (SeO3) 2- These results highlight the value and importance of MOFs with non-structural ligand instability in achieving anion absorption.

[0080] Similarly, not bound by theory, another absorption pathway could be the adsorption of sodium selenate / sodium selenite salts via, for example, oxygen-selenium anion / node-water (hydroxyl) hydrogen bonds. ICP-OES (Inductively Coupled Plasma Emission Spectroscopy) measurements showed no sodium adsorption in the MOF, indicating that the adsorbate could not be a salt. This means that each adsorbed oxygen-selenium dianion must achieve charge balance by losing two anionic ligands (presumably hydroxides) from the MOF. ICP-OES measurements also determined that zirconium was not lost into the solution.

[0081] Figure 6 To visualize the absorption kinetics of selenate and selenite in NU-1000, UiO66-NH2, and UiO66-(NH2)2, graphs were used. Considering the high capacities of UiO-66-NH2, UiO-66-(NH2)2, and NU-1000 for selenate and selenite, SeO2 was also evaluated. x 2 The kinetics of absorption. For example... Figure 6 As shown, the limited high-capacity absorption from a 100 ppm solution using UiO-66-(NH2)2 requires approximately 70 hours or more, using UiO-66-NH2 requires approximately 27 hours, while using NU-1000 requires less than 3 hours. The faster absorption of NU-1000 compared to UiO-66 and its derivatives may be related to the pore size and orifice. NU-1000 has pore sizes with diameters of [missing information]. and The UiO-66 has triangular and hexagonal holes with the same size openings (Figure 4A), while the UiO-66 includes holes with diameters of... and The tetrahedral and octahedral holes, and have The opening. Figure 4B Octahedral pores are shown. The pore sizes of UiO-66-NH2 and UiO-66-(NH2)2 are expected to be even smaller. The radii of the selenate and selenite anions are respectively... and Therefore, based solely on the comparison between pore size and analyte size, it can be predicted that selenate and selenite diffuse faster through the pores of NU-1000 than within the UiO-66 derivative.

[0082] A significant characteristic of both NU-1000 and UiO-66-NH2 is their ability to absorb selenate and selenite ions with essentially equal efficiency in terms of kinetics and absorption capacity. The ability to adsorb both forms of inorganic selenium is a crucial feature of selenium remediation. The combination of high absorption capacity and rapid absorption time with NU-1000 suggests that both pore size and the presence of substituted ligands (water and hydroxyl groups) at the Zr6 nodes are likely important for achieving both high absorption capacity and rapid absorption kinetics.

[0083] Analysis of the periodic table suggests that MOFs such as NU-1000 can also be expected to absorb oxygen-containing anions of the following elements in a manner similar to selenium: aluminum (i.e., water-soluble aluminum oxide / hydroxide), silicon (i.e., silicate and hydrosilicate), phosphorus (e.g., phosphate and hydrogen phosphate), sulfur (i.e., sulfate), chlorine (e.g., chlorate and perchlorate), germanium (i.e., water-soluble germanium oxide / hydroxide), arsenic (e.g., arsenate), tin (i.e., stannate), antimony (e.g., antimonate and antimonite), iodine (e.g., iodate, periodate, and iodate), and lead (i.e., water-soluble lead oxide / hydroxide).

[0084] To gain a deeper understanding of the adsorption mechanism of selenate and selenite on NU-1000, the maximum adsorption capacity of each Zr6 node was determined. When exposed to aqueous solutions containing various concentrations of selenate and selenite anions ranging from 2 to 7 per node, the maximum adsorption capacity of NU-1000 was found to be two anions per node (Table S1). Furthermore, under these conditions, NU-1000 showed similar affinities for selenate and selenite, suggesting that these two analytes may bind in a similar manner. At initial concentrations corresponding to more than six per node (for solution volume and amount of adsorbent tested >90 ppm Se), NU-1000 showed adsorption of more than two anions per node, accompanied by adsorption of sodium cations. This adsorption of sodium indicates that NU-1000 no longer achieves its inherent charge balance when more than two anions are adsorbed per node. In the absence of Na… + In the case of co-bonding, for each adsorbed doubly charged selenate or selenite anion, the MOF must relinquish two negative charges to maintain charge balance. One way NU-1000 can accommodate two selenate or selenite anions (-4 charge) per node is by replacing all four terminal hydroxyl groups (OH-) at the Zr6 node. - As detailed below, it may also replace water molecules (Figure 4A).

[0085] Table S1. Adsorption of selenite and selenate ions at each node in NU-1000 when exposed to aqueous solutions of sodium selenate and sodium selenite at different concentrations. *Na+ was also adsorbed.

[0086]

[0087] The diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) method was used to gain a deeper understanding of the positions of the two analyte molecules at each node of the NU-1000. Figure 8A The DRIFTS spectra of the synthesized NU-1000 (lower trace) and after the adsorption of two molecules, selenite (middle trace) and selenate (upper trace), are shown. Figure 8B Display range from 4000-2000cm -1 Magnified DRIFTS spectrum. Figure 8C This demonstrates the possible binding modes of selenate (or selenite) to the nodes of NU-1000. The IR spectrum of NU-1000 at 3670 cm⁻¹ before analyte adsorption is shown. -1 Contains a spike ( Figure 8A / B, the lowest trace), corresponds to the stretching of the –OH group at the node end (Fig. 4a). The spectrum is still at 2745 cm⁻¹. -1 Contains a small peak ( Figure 8A The lower trace ( / B) corresponds to the OH stretching from the hydrogen bonds between water and hydroxyl ligands at the Zr6- nodes (Fig. 4A). After adsorbing approximately two selenate or selenite molecules at each node, at 3670 cm⁻¹... -1 The stretching of OH is greatly reduced at 2745cm. -1 The hydrogen-bonded OH stretching completely disappeared (respectively). Figure 8A / B's middle and upper traces). Based on this information, it is reasonable to propose each SeO4. 2- or SeO3 2- The anions replace both terminal hydroxyl groups on the Zr6- nodes. Therefore, when two analyte molecules bind to each node, all four terminal hydroxyl groups are replaced, and analyte binding can occur in either an η2μ2 or μ2 manner. Figure 8C ).

[0088] Structural changes associated with the binding of selenate and selenite anions were assessed using pair distribution function (PDF) analysis of total X-ray scattering data. Figure 9A Displays the calculated difference pair distribution functions (PDFs) for NU-1000 loaded with selenite and selenate. Figure 9B Experimental differential PDFs for NU-1000 loaded with selenite and selenate are shown, revealing only the peak at the distance matching η²μ² binding. Simulated PDFs indicate that for η²μ² and μ² binding, the Se-Zr distances are respectively... and ( Figure 9A The experimental PDF results, evaluating the atomic-atomic distance unique to the separation of adsorbent / adsorbate combinations from the differential data, are shown in [the PDF]. (Selenite is) Selenate is The characteristics of ) and not in This clearly demonstrates that these anions bind only in the η²μ² mode. Figure 9B (The curve for selenite is higher on the left side). Both difference PDFs are in... The peaks attributable to the Se-O distance within the anion, and in A characteristic consistent with the slight contraction of the average Zr-O distance.

[0089] Figure 10 The absorption-time of selenate and selenite at low and initial concentrations of 1000 ppb (as Se) in NU-1000 (2 mg) is shown. To test whether using NU-1000 as an adsorbent meets current EPA standards for selenium in water, the absorption of selenate and selenite at low concentrations was also investigated. When exposed to 5 mL of an aqueous solution of 1000 ppb selenium (as sodium selenite or sodium selenate), 2 mg of NU-1000 adsorbed 98% of the selenate or selenite in the solution in less than 5 minutes. After 3 hours, the amount adsorbed remained constant, meaning that the adsorbed anions did not subsequently leach from the adsorbent after 5 minutes. With a residual solution concentration of only ~20 ppb selenium, the test samples treated with NU-1000 met the EPA standard of <50 ppb selenium for drinking water. It is anticipated that technicians in fields such as engineering fluid purification equipment will be able to optimize these results so that NU-1000MOF can contact a continuous flow of selenate and selenite aqueous solutions and produce an effluent flow with a concentration of these ions at the level of 10 parts per billion (as selenium) after an appropriate contact time.

[0090] Still at 40℃ Figure 11 ) and pH 6 ( Figure 12 The adsorption of low concentrations of selenate and selenite by NU-1000 was tested to simulate the conditions of circulating cooling water in the flue gas desulfurization process of power plants where selenate and selenite treatment is of concern. Figure 11 The absorption-time of selenate and selenite in NU-1000 (2 mg) at low concentrations and 40°C and an initial concentration of 1000 ppb (as Se) was shown. Figure 12The absorption-time of selenate and selenite in NU-1000 (2 mg) at low concentrations and pH 6 and an initial concentration of 1000 ppb (as Se) was shown. Successful testing demonstrates that NU-1000 is a promising candidate for the removal of selenite or selenate under power plant operating conditions.

[0091] Figure 13A -E shows the amount (q)-time of adsorption at each node of NU-1000 at different concentrations of selenite and selenite, where the amount adsorbed is expressed as milligrams of total oxygen-containing anions normalized to the gram weight of bare NU-1000 MOF. Figures 14A-C show the Langmuir plots (linear, type I) of selenite and selenate adsorption on NU-1000, with the amount adsorbed as the weight of total oxygen-containing anions. The amount of selenite and selenate adsorbed per gram of NU-1000 can be determined by exposing the MOF to various concentrations of selenite or selenate and monitoring the amount (q) mg / g adsorbent of the analyte over time. Figure 13A -E). Adsorption isotherm data were fitted using the Langmuir model, yielding high correlation coefficients (Figures 14A-C). Using the Langmuir equation, the maximum adsorption capacity (Q) of NU-1000 for selenite was 95 mg / g, and for selenate it was 85 mg / g. These data can be roughly compared to millimoles of analyte per gram of absorbent medium. At the levels of 1.00 to 3.00 selenite or selenate anions (i.e., concentration and volume) corresponding to each node, NU-1000 reached its maximum adsorption within 1 minute of exposure (Figure 13). The adsorption capacity of NU-1000 makes it the highest-capacity selenate and selenite adsorbent described to date; these analytes contain oxygen-containing anions that are much larger than typical sulfate or chloride anions and are more difficult to fully absorb in many commercially available typical adsorption or ion exchange media. The absorption time of less than 1 minute particularly distinguishes NU-1000 from other materials (such as alumina and iron oxide derivatives, as well as ion exchange and polymer resins), each of which requires 30 minutes or more to reach maximum adsorption capacity under equivalent conditions. This characteristic, along with the low equilibrium final Se concentration observed in NU-1000, likely reflects the significantly improved binding capacity of MOFs for larger oxygen-containing anions compared to other available adsorption media.

[0092] Figure 14 shows the adsorption capacity (q) as a function of time at different concentrations, where q = (C i -C f )x V / m and C i = Initial concentration of selenate or selenite, C f= The final concentration at a given time, V = the volume of selenate or selenite solution used, m = the mass of NU⁻¹⁰⁰. For the Langmuir plot shown, a type I linear equation is used (Figure 14), where C e = The equilibrium concentration of selenate or selenite in the solution, q e =Equilibrium adsorption capacity, Q = NU - 1000, the maximum adsorption capacity, and K L = Langmuir adsorption constant. Based on Figure 13 and the analysis described above, q... e and C e Let q and C be respectively. f The average value.

[0093] Table S2. Figure 14 shows the C values ​​used for selenate and selenite adsorption on NU-1000. e and q e value.

[0094]

[0095] Figure 15A The powder X-ray diffraction pattern of the synthesized NU-1000 is shown compared to that of NU-1000 after adsorption of selenite or selenate. Figure 15B The nitrogen adsorption isotherm of synthesized NU-1000 is shown compared to NU-1000 after adsorption of selenite or selenate. Characterization of NU-1000 before and after adsorption of selenate and selenite shows that the framework remains intact. The powder X-ray diffraction pattern remains unchanged before and after adsorption. The Brunauer-Emmett-Teller (BET) volume surface area of ​​NU-1000 before adsorption is 1035 ± 5 m². 2 / cm 3 (Weight surface area: 2130±5m²) 2 / g), while the volume surface area decreased slightly to 682±10 after adsorption of selenate and selenite. 2 / cm 3 and 705±10 2 / cm 3 (Weight surface area: 1240±10 and 1300±10 m²) 2 / g)( Figure 15B It has been reported that a similar modest decrease occurred after Al(III) mounting on the nodes of NU-1000 via atomic layer deposition.

[0096] Figure 16A -C shows the absorption of selenate and selenite as a function of time using 2 mg NU-1000 and 10 mL of aqueous solutions containing 100 ppb Se and (a) 100 ppb sulfur S with (b) 500 ppb S and (c) 1000 ppb S (as sulfate). Specifically, Figure 16A -C indicates the performance of NU-1000MOF in the presence of competing sulfate anions using nodal absorption of selenate and selenite.

[0097] Initially, batch adsorption studies were conducted on selenate and selenite uptake in the presence of sulfate in naked MOFs, and as a "knock-off study" in which sulfate was exposed to MOFs that had already adsorbed selenium oxyanions. This was achieved by exposing 2 mg NU-1000 to 10 mL of solution containing 100 ppb Se (as SeO4). 2- or SeO3 2- ) and 100, 500 or 1000 ppb S (as SO4) 2- The competitive adsorption of Se in aqueous solution was investigated. In all cases, >95% of the Se in the solution was adsorbed. Figure 16A -C), and at these concentrations, SO4 2- The presence (up to ten times higher concentration, ppb) of SeO4 2- or SeO3 2- Absorption was unaffected. Furthermore, the residual Se selenium concentration (as SeO3) was found to be... 2- or SeO4 2- The values ​​were between 2-7 ppb and 4-9 ppb Se, respectively.

[0098] By first exposing 2 mg NU-1000 to 10 mL containing 24 ppm Se (as SeO4) 2- and SeO3 2- An aqueous solution of SeO4 was used for a "knock-off" study. This is equivalent to an exposure level of 3.3 Se / node to ensure that NU-1000 uses SeO4. 2- and SeO3 2- Saturate. Then make NU-1000-2SeO4 2- and NU-1000-2SeO3 2- Exposure to SO4 containing 25 ppm 2- (Equivalent to 3 S / node) aqueous solution, and probe SeO4 as a function of time. 2- and SeO3 2- Leaching. In SO4 2- In the presence of NU-1000-2SeO3 2- Leaching SeO3 2- At least (3%), while in SO4 2- In existence, from NU-1000-2SeO4 2- Leaching SeO4 2-More significant (20%), but still low compared to many other types of adsorption media for which it is difficult to achieve adsorption of the two forming substances selenium oxygen anions even without sulfate, not to mention the knock-off challenge.

[0099] The following describes the general method used for the above analysis. UiO-66, UiO-66-NH2, UiO-66-(NH2)2, UiO-66-(OH)2 and UiO-67 are based on Katz, MJ; Brown, ZJ; YJ; Siu, PW; Scheidt, KA; Snurr, RQ; Hupp, JT; Farha, OKA facile synthesis of UiO-66, UiO-67 and their derivatives. Chem. Commun. 2013, 49, 9449-9451, is produced according to the procedure described therein, which is incorporated herein by reference in its entirety. NU-1000 is produced according to the procedure described in Planas, N.; Mondloch, JE; Tussupbayev, S.; Borycz, J.; Gagliardi, L.; Hupp, JT; Farha, OK; Cramer, CJ Defining the Proton Topology of the Zr6-Based Metal-Organic Framework NU-1000. J. Phys. Chem. Lett. 2014, 5, 3716-3723, which is incorporated herein by reference in its entirety. Powder X-ray diffraction measurements were obtained using a Bruker MXI μS microsource with Cu-Kα radiation and an Apex IICCD detector. Measurements were performed in the range of 2° < 2θ < 37°. N2 adsorption and desorption isotherms were measured at 77 K on a Micromeritics Tristar II. The sample was activated by heating at 120 °C for 12 h under high vacuum on a Micromeritics Smart VacPrep. All gases used were of Grade 5 ultrapure purity obtained from Airgas Specialty Gases. DRIFTTS were recorded on a Nicolet 6700 FTIR spectrometer equipped with an MCT detector cooled to 77 K. Spectra were collected in a KBr mixture under argon purging (sample prepared in air). Pure KBr was measured as background and subtracted from the sample spectrum. ICP-OES data were collected on a Varian Vista MPX ICP spectrometer. ICP-MS data were collected on a ThermoFisher X Series II instrument equipped with collision cell technology (CCT) to reduce interference from doublets for accurate Se detection. ICP standards were purchased from Fluka Analytical. The purchased Na and Se ICP standards were 1000 mg / L (TRACECERT) in 2% nitric acid, and the Zr standard was 10000 μg / mL in 4% wt%. Standards for ICP-OES measurements (0.25–10 ppm) were prepared by serial dilution in 3% H₂SO₄, and standards for ICP-MS measurements (4–1000 ppb) were prepared by serial dilution in 3% HNO₃.The scattering data used in the PDF analysis were collected at the Advanced Photon Source (APS) beamline 11-ID-B at Argonne National Laboratory (ANL). The high-energy X-rays were 58.66 keV. This was used in conjunction with a Perkin Elmer amorphous silicon-based planar detector. Samples were loaded into a Kapton capillary for PDF measurements under ambient conditions. PDF measurements were collected from NU-1000 samples containing selenate or selenite by performing 60 frames of 2-second exposures. The 2D scattering images were integrated using the Fit2D software to obtain 1D scattering intensity data. The structure function S(Q) was obtained within the PDFgetX3 software. The direct Fourier transform of the simplified structure function F(Q) = Q[S(Q)⁻¹] yielded the simplified pair distribution function G(r), and... The contribution from the original MOF was measured under identical conditions and subtracted to obtain the differential PDF (dPDF). The dPDF data shows the new contribution from Se atom correlations. A model of the Se coordination mode (η2μ2 or μ2) for the MOF Zr-cluster was constructed within CrystalMaker. PDFGui was used. 32 Simulate PDFs for both models and compare them with the experimental model.

[0100] An initial selenite / selenate uptake study was conducted by exposing 10 mg of MOF in a 15 mL polypropylene centrifuge tube to 5 mL of an aqueous solution of 100 ppm selenite (as sodium selenite or sodium selenate). Control solutions of 100 ppm sodium selenite and sodium selenate were also prepared. The solutions were centrifuged for 1 minute to allow the MOF to settle to the bottom of the tube. After 72 hours, 0.5 mL of the supernatant was removed and diluted to 10 mL in 3% H₂SO₄ for ICP-OES measurements. The concentrations of Se, Zr, and Na in each solution were determined using ICP-OES. The amount of selenate or selenite adsorbed by the MOF was determined by comparing the control solutions with those containing MOF.

[0101] Kinetic studies were conducted by exposing 10 mg of UiO-66-(NH2)2, UiO-66-NH2, and NU-1000 to 5 mL of an aqueous solution of 100 ppm selenium (as sodium selenite or sodium selenate) in 15 mL polypropylene centrifuge tubes. The solutions were centrifuged for 1 minute to allow the MOF to settle to the bottom of the tube. At 3, 27, and 72 hours, 0.5 mL of the supernatant was aliquoted and diluted to 10 mL in 3% H2SO4 for analysis by ICP-OES. The concentrations of Se, Zr, and Na in each solution were determined by ICP-OES. The amount of selenate or selenite adsorbed by each MOF was determined by comparing the control solutions with those containing the MOF.

[0102] The maximum absorbance of each node of NU-1000 was determined by exposing 2 mg of NU-1000 in a 15 mL polypropylene centrifuge tube to 5 mL of sodium selenite or sodium selenate aqueous solution with selenium concentrations of 30, 45, 60, 75, 90, and 105 ppm. These concentrations correspond to exposure levels of 2–7 analyte molecules per MOF node (i.e., Zr6 cluster). The solutions were centrifuged for 1 minute to allow the MOF to settle to the bottom of the tube. Aliquots of the supernatant were removed and diluted to 10 mL in 3% H2SO4 for analysis by ICP-OES. The concentrations of Se, Zr, and Na in each solution were determined by ICP-OES. The number of selenate or selenite anions adsorbed at each node of NU-1000 was determined by comparing the control solutions with those containing MOF.

[0103] Low-concentration kinetic studies were conducted by exposing six 2 mg NU-1000 samples in 15 mL polypropylene centrifuge tubes to 5 mL of an aqueous solution of 1 ppm selenium (as sodium selenite or sodium selenate). The solutions were centrifuged for 1 minute to allow the MOF to settle to the bottom of the tube. Aliquots of 2895 μL of supernatant were taken from each solution at different times (5, 10, 15, 30, 60, and 180 minutes) and diluted to 3 mL in 3% HNO3 for analysis by ICP-MS. The concentrations of Se, Zr, and Na in each solution were determined by ICP-MS. The amount of selenate or selenite adsorbed by each MOF was determined by comparing the control solutions with those containing the MOF. Studies were conducted in the same manner at 40 °C and pH 6. For testing at 40 °C, selenate and selenite solutions were heated in beakers filled with Lab ARMOR BEADS, and for testing at pH 6, selenate and selenite solutions were prepared in pH 6 HCl.

[0104] The amount of selenate or selenite adsorbed per gram of NU-1000 was determined by exposing 5 mg of NU-1000 in a 15 mL polypropylene centrifuge tube to 10 mL of an aqueous solution containing selenium (as sodium selenite or sodium selenate) at concentrations of approximately 18, 27, 36, 45, and 55 ppm. These concentrations correspond to exposure levels of 1.00, 1.50, 2.00, 2.50, and 3.00 analyte molecules per Zr6- node of NU-1000. The solutions were centrifuged for 30 seconds to allow the MOF to settle to the bottom of the tube. Aliquots of the supernatant were removed and diluted to 10 mL in 3% H2SO4 at 1, 2, 3, 4, 5, 10, 15, 30, 60, 90, 120, and 180 minutes for analysis by ICP-OES. The concentrations of Se, Zr, and Na in each solution were determined by ICP-OES. The amount (q) (mg / g) of selenate or selenite adsorbed by NU-1000 was determined by comparing the control solution with those containing MOF, where q = (Ci - Cf) x V / m, Ci = initial concentration, Cf = final concentration, V = volume of solution exposed to NU-1000, and m = mass (g) of NU-1000.

[0105] As described above, Zr-based MOFs, including, for example, NU-1000, can remove oxygen-containing anions from other oxygen-containing anions, such as aluminum (i.e., water-soluble aluminum oxide / hydroxide), silicon (i.e., silicate and hydrosilicate), phosphorus (e.g., phosphate and hydrogen phosphate), sulfur (i.e., sulfate), chloride (e.g., chlorate and perchlorate), germanium (i.e., water-soluble germanium oxide / hydroxide), arsenic (e.g., arsenate), tin (i.e., stannate), antimony (e.g., antimonate and antimonite), iodine (e.g., iodate, periodate and iodate), and lead (i.e., water-soluble lead oxide / hydroxide).

[0106] In some implementations, Zr-based MOFs, including NU-1000, are used to adsorb antimony-containing oxyanions, including redox states of Sb[III] (antimony) or Sb[V] (antimony). Antimony is used as a neutron source (paired with beryllium) in pressurized water reactors; therefore, antimony is a component of wastewater generated by nuclear power plants. During nuclear power plant shutdowns, antimony is also released from the fuel oxide layer into the primary cooling water, resulting in significant radiation doses to personnel and the surrounding environment. Common forms of antimony present in aqueous solutions under oxidizing conditions include Sb(OH)6-, HSbO2, Sb(OH)3, and Sb(OH)2. 4+ Therefore, antimony oxygen-containing anions can be removed from these sources, including those listed above, using Zr-based MOFs (including NU-1000).

[0107] NU-1000 was exposed to Sb(OH)6- concentrations corresponding to 2–7 Sb / nodes. Aliquots were collected from the supernatant at 24 and 48 hours. Table S3 shows the amount of Sb(OH)6- adsorbed by NU-1000 at each node. Antimony adsorption at each node in NU-1000 was performed using Sb(OH)6- as the antimony source at 24 and 48 hours.

[0108] Table S3. Antimony adsorption at each node in NU-1000 after 24 and 48 hours using Sb(OH)6- as the antimony source.

[0109]

[0110] Figure 17A -B shows the absorption of Sb(OH)6- over time as an absorbance per node. Tests were performed to determine the Sb(OH)6- absorption over time at Sb / Zr6 nodes corresponding to Sb(OH)6- concentrations of 1.00, 1.50, 2.00, 2.50, and 3.00. Aliquots were taken from each solution at 1, 5, 10, 15, 30, 60, 90, 120, 180, 240, 300, 360, 420, 1440, 1800, and 2880 minutes. These results show that the adsorption kinetics of Sb(OH)6- in NU-1000 are rapid, reaching over 60% of the total capacity in less than 1 minute. Figure 18 Show from Figure 17A Langmuir fit of the Sb adsorption isotherm of -B. Figure 18 The maximum adsorption capacity of Sb(OH)6- shown in NU-1000 is 260 mg / g (or only 142 mg / g Sb).

[0111] Figure 19 Powder X-ray diffraction patterns of NU-1000 and NU-1000 with Sb(OH)6- are shown. This indicates the stability of NU-1000 after adsorption of Sb(OH)6-. PXRD, nitrogen adsorption-desorption isotherms, and ICP-OES measurements were performed to determine the overall crystallinity, porosity, and Zr leaching, respectively. The PXRD pattern shows that the overall crystallinity of NU-1000 remains intact after adsorption. Figure 20 The nitrogen isotherms for NU-1000 and NU-1000 with Sb(OH)6- are shown. This indicates that, considering the addition of material to the framework, the surface area of ​​the material decreases to approximately the expected level. Finally, no Zr leaching from the framework was observed by ICP-OES.

[0112] Similar to the adsorption of oxygen-containing anions by selenium, the adsorption of oxygen-containing anions by lead can be anticipated using Zr-based MOFs including NU-1000. Lead in caustic solutions (where its oxygen-containing anionic form is as previously determined) is believed to be associated with intergranular corrosion / stress corrosion cracking of steam generator tubes in nuclear power plants. Therefore, it would be beneficial to remove these oxygen-containing anions from the relevant liquid streams, including Pb[II] or Pb[IV] redox states, such as Pb(OH)6. 2- Pb(OH)6 4- PbO3 2- and PbO2 2- .

[0113] It should be understood that in some embodiments, the MOFs of the present invention provide adsorption of oxygen-containing anions even in the presence of other substances that may compete for adsorption sites on the MOF. Specifically, in certain liquid streams, such as those in flue gas desulfurization systems, oxygen-containing anions of boron and sulfur in the liquid phase may compete for adsorption sites on the MOF. However, even in the presence of these substances, the MOFs of the present invention have been found to still provide adsorption of oxygen-containing anions. Those skilled in the art will understand that when determining the concentration of the MOF to be used for the liquid stream of interest, the concentrations of the various substances, including the oxygen-containing anions to be adsorbed and any competing substances, should be considered.

[0114] Tables S4, S5, and S6 show the test results of using NU-1000 in flue gas desulfurization liquid stream samples before and after the addition of NU-1000. (Regarding Table S4, it should be recognized that Stage 1 FGD wastewater may contain more particulate selenate / selenite compared to soluble oxygen-containing anions, which may result in a relatively small adsorption amount after exposure to MOF).

[0115] Table S4. FGD wastewater (10 mL) before and after treatment with NU-1000 (10 mg).

[0116]

[0117] Table S5. FGD wastewater (10 mL) before and after treatment with NU-1000 (10 mg).

[0118]

[0119] Table S6. Se absorption from FGD wastewater using various amounts of NU-1000.

[0120]

[0121] Regarding Tables S4 and S5, adding 10 mg of NU-1000 to 10 mL of wastewater corresponds to exposure levels of 15 B / Zr6, 26 S / Zr6, and only 0.007 Se / Zr6, which are very challenging competing conditions. Table S4 shows the levels of B, Se, and S in the wastewater after treatment with NU-1000, and the MOF absorbed only 100 ppb B, 43 ppb Se, and 160 ppb S. Considering that the exposure levels of B and S are 2100x and 3700x of Se, respectively, NU-1000 can still adsorb Se. Therefore, in some embodiments, the adsorption of selenium oxyanions still occurs in the presence of ions in the range of 100-10,000x selenium oxyanion concentration.

[0122] Regarding Table S6, the SeOx content of different amounts of NU-1000 (50 mg, 25 mg, 10 mg, 5 mg) from stage 3 FGD water was tested. 2- The removal of MOFs was achieved, and data points were acquired at shorter times (5 min, 10 min, 30 min). This shows the minimum MOF amount and the shortest time to obtain the desired results. Table S6 clearly shows that the effluent concentration of residual oxygenated anions in the plant water samples decreased with increasing MOF amount and exposure time. Improvements in MOF exposure time and MOF loading appear to be comparable in improving oxygenated anion uptake capacity.

[0123] The crystal size range of the Zr-based MOFs of the present invention can vary, while still providing the aforementioned adsorption of oxygen-containing anions. In some embodiments, the crystal size of NU-1000 can be in the range of about 75-5000 nm. In some embodiments, the crystal size of NU-1000 can be in the range of about 75-1200 nm or about 300-5000 nm. In some embodiments, NU-1000 can be in the range of 75-1200 nm. In some embodiments, the MOFs of the present invention can have relatively large pore sizes, for example, a maximum of approximately Larger or even larger pores in MOFs facilitate the diffusion of the analyte and improve absorption kinetics. It should be understood that, compared to smaller geometries, larger MOF pores will allow oxygen-containing anions to diffuse more easily to available nodes for absorption.

[0124] Based on the foregoing, the present invention provides the use of the above-mentioned MOFs and their ability to remove anionic substances, and the attachment of multiple ligands to the MOF structure to complex certain cationic substances in addition to removing anionic substances. The following is a description of the ligands to be attached to the MOF for complexing a given cationic substance, followed by a description of their synthetic side groups (such as side benzyl groups). Their synthesis and attachment to side groups (such as side benzyl groups) on the MOF of the present invention are further described thereafter, for example, through the linking group portion of the MOF, to provide a coordinated MOF according to the present invention for removing both anionic and cationic substances from a liquid or liquid stream.

[0125] Figure 21 This illustrates a general compound for removing cations from a liquid according to one embodiment of the invention. As shown, the compound has the formula R1-SO2-S-R2-SH, where R1 is typically a supporting molecule having a suitable side group to which a ligand (-SO2-S-R2-SH, where R2 is an alkyl group) can be attached. The ligand is a thiosulfonyl-thiol (-SO2-S-R2-SH) ligand, also known as a thio-alkyl-sulfonyl-thiol ligand, where R2 is an alkyl group, in some embodiments propyl or ethyl. In one embodiment, the supporting molecule R1 can be a MOF of the invention having a suitable side group to which the ligand can be attached. In some embodiments, a benzyl group can be used as the sulfonyl group attachment point of the ligand. In other words, the MOF can have a usable side benzyl group to which the ligand is attached via a sulfonyl group (i.e., -SO2-) functional group of the ligand. It should be understood that the supporting molecule, such as the MOF, should be able to withstand the conditions required for ligand synthesis / attachment to usable side groups for the present invention.

[0126] It should be understood that in some embodiments, the sulfonyl group attached to the MOF allows the thioalkyl group to be nucleophilically attacked by the sulfonyl group attached to the MOF. Therefore, a supporting molecule having any side group to which the sulfonyl group is attached and which itself is nucleophilically attackable, such as the MOF of the present invention, can be used to support the ligands of the present invention. Furthermore, the resulting structure of a supporting molecule with attached ligands, such as the MOF of the present invention, should be sufficiently stable to retain the complexation of large divalent cations (e.g., lead (Pb)). 2+ The ability to reverse the bite geometry.

[0127] Figure 22 This illustration shows a compound according to an embodiment of the invention for removing cations from a liquid. As shown, in this embodiment, the compound has... Figure 1 The structure of the compound, wherein the alkyl group (R2) is an ethyl group.

[0128] Figure 23 This illustrates another compound according to another embodiment of the invention for removing cations from a liquid. As shown in the figure, in this embodiment, the compound has... Figure 1 The structure of the compound, wherein the alkyl group (R2) is propyl.

[0129] The compounds of the present invention can be synthesized by starting with a supporting molecule, such as the MOF of the present invention. To attach a thiosulfonyl-thiol (-SO2-S-R2-SH) ligand (also known as a thioalkyl-sulfonyl-thiol ligand) to the inner surface or pore of the NU-1000 MOF cavity, a suitable side group, such as a side benzyl group, must be added to the structure of the MOF. Such ligand exchange or insertion is known to be performed using MOF chemicals called SALE or SALI. Once the side group, such as the side benzyl group, is attached, it will essentially suspend from the MOF surface structure, for example, within the MOF cavity from the inner MOF surface structure or near or at the pore of the MOF cavity.

[0130] The sulfonic acid moiety can then be synthesized onto the MOF via this side group. As mentioned above, in one embodiment, the side group can be a side benzyl group. Therefore, the following synthesis will be described using a side benzyl group as the side group. The sulfonic acid moiety can then be synthesized onto the MOF via this side benzyl group by reacting with thionyl chloride to generate sulfonyl chloride or by reacting with excess chlorosulfonic acid. It should be understood that, in some cases, the simultaneous use of thionyl chloride and chlorosulfonic acid during the addition of the sulfonic acid moiety can allow the inorganic chloride to be added to the aromatic benzene ring. In some embodiments, thionyl chloride can be used in post-synthesis or subsequent cold washing. It should also be understood that storage of chlorosulfonated MOFs (e.g., in bead form) can lead to the hydrolysis of the sulfonyl chloride group into a sulfonic acid group. However, subsequent treatment with thionyl chloride can convert the sulfonic acid into a sulfonyl chloride to provide complete chlorosulfonation of each side benzyl ring.

[0131] Once sulfonyl chloride has been generated, a ligand precursor terminated at both ends by thiols can be reacted with the polymeric sulfonyl chloride in a suitable alkaline buffer system. One end of the ligand precursor is linked to the sulfonic acid functional group of the polymer via a thio-sulfonyl bond. Thus, the ligand can be attached to each recognizable sulfonyl group on the MOF via a thionyl chloride intermediate chemical in a moderately alkaline environment to produce an overall compound structure of R1-SO2-S-R2-SH, where R1 is the MOF of the present invention having a side benzyl group attached to the ligand (-SO2-S-R2-SH), and R2 is an alkyl group that may be propyl or ethyl. Importantly, the basic components of the buffer are not independent of the thio-thiol attack on the thionyl chloride. In some embodiments, the alkaline solution in which the ligand precursor is attached to the sulfonic acid portion of the MOFs contains sodium hydroxide and may have a pH of about 10-11.

[0132] To form compounds in which the alkyl group (R2) is an ethyl group (see...) Figure 22 In one embodiment, the sulfonyl chloride on the MOF can react with 1,2-dimercaptoethane as follows:

[0133] [MOF]-(C6H5-SO2-Cl)+HS-[CH2]2-SH+NaOH(aq)→[MOF]-(C6H5-SO2-S-[CH2]2-SH)+NaCl(aq)+H2O(1)

[0134] Specifically, prepare a homogeneous solution of 1,2-dimercaptoethane, sodium hydroxide, and dimethoxyethane (monoethylene dimethyl ether, an ether solvent). The reaction pH should be approximately 10-11. The reaction must be sufficiently basic so that 1,2-dimercaptoethane can exist as an anion to condense with the sulfonyl chloride group on the MOF. If the base is too strong, the sulfonyl chloride may hydrolyze, thus preventing the reaction with 1,2-dimercaptoethane. If the base is too weak, this may also prevent the reaction with 1,2-dimercaptoethane.

[0135] The MOF containing sulfonyl chloride (e.g., [MOF]-(C6H5-SO2-Cl)) can then be added to the homogeneous solution above. The MOF containing sulfonyl chloride can be slowly added dropwise to the solvated dimercaptoalkane solution while maintaining the reaction vessel containing the solution on ice, as the reaction is exothermic. In some embodiments, the temperature can be maintained at approximately 0-4°C. Various washing solutions can then be used, such as those using water, methanol, and ethyl acetate. The coordinated MOF can then be dried and ready for use.

[0136] To form a compound in which the alkyl group (R2) is propyl (see...) Figure 23 In one embodiment, the sulfonyl chloride on the MOF can react with 1,3-dimercaptopropane as follows:

[0137] [MOF]-(C6H5-SO2-Cl)+HS-[CH2]3-SH+NaOH(aq)→[MOF]-(C6H5-SO2-S-[CH2]3-SH)+NaCl(aq)+H2O(2)

[0138] Specifically, prepare a homogeneous solution of 1,3-dimercaptopropane, sodium hydroxide, and dimethoxyethane (monoethylene dimethyl ether, an ether solvent). The reaction pH should be approximately 10-11. The reaction must be sufficiently basic so that 1,3-dimercaptopropane can exist as an anion to condense with the sulfonyl chloride group on the MOF. If the base is too strong, the sulfonyl chloride may hydrolyze, thus preventing the reaction with 1,3-dimercaptopropane. If the base is too weak, this may also prevent the reaction with 1,3-dimercaptopropane.

[0139] The MOF containing sulfonyl chloride (e.g., [MOF]-(C6H5-SO2-Cl)) is then added to the homogeneous solution above. The MOF containing sulfonyl chloride can be slowly added dropwise to the solvated dimercaptoalkane solution while the reaction vessel containing the solution is kept on ice, as the reaction is exothermic. In some embodiments, the temperature is maintained at approximately 0-4°C. The mixture can then be washed with various washing solutions, such as water, methanol, and ethyl acetate. Afterward, the coordinated MOF can be dried and then ready for use.

[0140] In use, and according to one embodiment of the invention, a MOF of the present invention having a linking ligand for complexing a given cation can selectively remove a specific substance from a liquid stream. In use, the compound of the present invention, specifically, the MOF of the present invention having the linking ligand, can be in the form of a medium in contact with a given liquid or liquid stream containing selenium-containing oxyanions, such as selenite (SeO3). 2- ) and selenate (SeO4) 2- Antimony oxoanions, including Sb[III] (antimony) or Sb[V] (antimony) redox states; and lead oxoanions, including Pb[II] or Pb[IV] redox states, such as Pb(OH)6. 2- Pb(OH)6 4- PbO3 2- and PbO2 2- ; and the cations to be removed, such as large cations, including, for example, lead (Pb). 2+ ) or mercury (Hg 2+ For example, in some embodiments, the medium may be in the form of resin or resin beads. Other physical forms of media known in the art may be used in combination with known methods of contacting the liquid with such a medium for removing a given substance.

[0141] The specific MOF with the linking ligand can then be attached to, or held by, any structure that facilitates contact between the liquid stream containing the specific substance to be removed and the MOF with the linking ligand, such as a pre-coated filter / softener or a separate packed column, including such devices already used in a given facility or plant (e.g., existing containers for ion exchange). The structure can then be suitably installed to allow contact between the liquid stream and the MOF with the linking ligand on the structure. Once in contact with the liquid stream, the specific substance to be removed, including oxyanions and specific cations, is complexed by the MOF and the ligands linked to the MOF, respectively, thereby reducing the concentration of that substance in the liquid stream.

[0142] During contact between the MOFs of the present invention, having ligands of the present invention connected to the MOF for complexing cations, and a liquid containing one or more oxyanions and cations to be removed, the oxyanions are absorbed, complexed, or adsorbed by the MOF structure itself through nodes, while cations entering the cavity of the MOF are complexed or ionized with the ligands connected to the MOF. As described above, oxyanions can be adsorbed via zirconium nodes connected to the MOF.

[0143] The cation is complexed via disulfide interactions with the ligand, wherein the cation is complexed or ionically interacts with the thiosulfonyl moiety (particularly the mercapto-sulfur of the thiosulfonyl moiety) and the terminal thiol moiety (-SH), which essentially counter-bites the cation to form a five- or six-membered open ring or cyclic geometry, depending on whether the R2 alkyl group is ethyl or propyl, and it essentially binds the cation as part of the open ring. In this way, by using two sulfur groups that respectively contribute electronegativity to the positively charged cation, the cation is effectively complexed from two points on a single ligand. This ion interaction provides a more stable complex and reduces the ability of the complexed cation to be released back into solution based on equilibrium leakage.

[0144] Specifically, regarding the complexation of cations, in one embodiment, the cation being complexed is lead (Pb). 2+ Therefore, the ligands of the present invention can be used to complex cationic lead (Pb) in the liquid phase. 2+ To remove cationic lead from liquids, a thiol attractor (also known as a terminal thiol-SH) is used as the ligand portion that absorbs the lead cation. The highest binding energy and fastest absorption kinetics are observed for lead cations when both reduced sulfur moieties bind to the same lead cation. Furthermore, using two thiols reduces or minimizes the release of bound lead back into solution, thus significantly limiting the effluent removal fraction for a given liquid stream. Therefore, instead of using two separate thiol-terminated ligand moieties to bind to the lead cation, a dithiol bond is used where, when the ligand has an ethylalkyl group (R2), a geometric backbiting produces a five-membered open-ring or cyclic geometry, or when the ligand has a propylalkyl group (R2), a six-membered open-ring or cyclic geometry. This allows the same ligand to provide two sulfur atoms, thereby providing electronegativity to the cationic lead. In some embodiments, this removal of cationic lead exceeds that otherwise achieved by ion exchange. It should be understood that this same type of dithiol bond can be used to complex mercury cations (Hg). 2+ Therefore, it should be understood that other similar cations can similarly complex and bind with the removal oxygen-containing anions to remove them from a given liquid or liquid stream.

[0145] Figure 24 An embodiment of the present invention is shown. Figure 22The interaction between the compound and lead cations is shown in this embodiment. Figure 22 The compound is R1-SO2-S-R2-SH, wherein R1 is the MOF of the present invention comprising a ligand (-SO2-S-R2-SH) linked to a suitable side group (e.g., a side benzyl group), wherein R2 is an ethyl group, and the dashed line represents the interaction with lead ions. (It should be understood that...) Figure 24 This is not intended to illustrate any spatial or otherwise proportional / three-dimensional aspect of the compound or the binding of lead.

[0146] As shown in the figure, lead is electronegatively complexed to the ligand via two bonds: a thiol-sulfur group on the thiosulfonyl moiety (or a thiol moiety adjacent to the sulfonyl group, also known as a thiosulfonyl bond) attached to the polymer, and a terminal thiol group at the end of the ligand. In other words, an alkyl group, in this case an ethylalkyl group, separates the lead along the two points to which the ligand is complexed. Thus, once associated with the ligand in this manner, lead essentially forms a geometry resembling a five-membered open ring composed of ligands bitten onto the cation. This adsorption interaction immobilizes the lead cation to the ligand linked to the MOF, thereby removing the lead cation from the liquid phase or liquid stream.

[0147] Figure 25 An embodiment of the present invention is shown. Figure 23 The interaction between the compound and cationic lead is shown. Figure 23 The compound is R1-SO2-S-R2-SH, wherein R1 is the MOF of the present invention comprising a ligand (-SO2-S-R2-SH) linked to a suitable side group (e.g., a side benzyl group), wherein R2 is propyl, and the dashed line represents the interaction with lead ions. (It should be understood that...) Figure 25 This is not intended to illustrate any spatial or otherwise proportional / three-dimensional aspect of the compound or the binding of lead.

[0148] As shown in the figure, lead is complexed by a ligand via two bonds: a thiol-sulfur group on the thiosulfonyl moiety (or a thiol moiety adjacent to the sulfonyl group, also known as a thiosulfonyl bond) attached to the polymer, and a terminal thiol group at the end of the ligand. In other words, an alkyl group, in this case propylalkyl, separates the lead along the two points to which the ligand is electronegatively complexed. Thus, once complexed to the ligand in this manner, lead is essentially trapped in a geometric six-membered open ring consisting of ligands back-biting onto the cation. This binding anchors lead to the ligand linked to the MOF, thereby removing lead from the liquid or liquid stream.

[0149] In some implementations, for thiopropylsulfonylthiol ligands (i.e., Figure 23The ligands can capture lead up to 200 mg / gm³. Tests have shown that lead concentrations in water up to 50 ppb (as lead nitrate) can be reduced to below 0.5 ppb within approximately a few minutes of exposure. Therefore, in some embodiments, the lead concentration in the effluent stream can be below 1 ppb or at ultra-low levels. Furthermore, when the analyte is lead in the form of nitrate, the pH of the effluent is close to that of concentrated nitric acid, indicating that the interaction between the dithiol complex or lead and the sulfur adjacent to the sulfonyl group (i.e., the thiol-sulfur of the thiosulfonyl moiety) is very stable, as the correspondingly low pH of the effluent does not show any detrimental effect on lead removal. Therefore, this reduces or eliminates the possibility of lead desorbing from the ligand back into the liquid or liquid stream.

[0150] It should be understood that the adsorption of anions by the MOF of the present invention as described above and the complexation of cations by ligands connected to the MOF as described above can occur within the same MOF compound. It should be understood that the adsorption of anions and the complexation of cations can occur simultaneously or sequentially, wherein the anion or cation is the first substance interacting with the MOF.

[0151] It should also be understood that alternative embodiments are possible, and the invention is not limited to the specific embodiments described above. For example, in some embodiments, aqueous selenate and selenite anions can be adsorbed via a series of highly porous, water-stable Zr-based MOFs. Both selenate and selenite anions are shown to be bound to the nodes in a bridging (η²μ²) manner, with one divalent anion bridging two zirconium metal centers. Antimony oxygen-containing anions, including Sb[III] (antimonite) or Sb[V] (antimonate) redox states, and lead oxygen-containing anions, including Pb[II] or Pb[IV] redox states, such as Pb(OH)₆, can also be adsorbed via a series of highly porous, water-stable Zr-based MOFs. 2- Pb(OH)6 4- PbO3 2- and PbO2 2- Furthermore, adsorption of these substances can be achieved even in the presence of competing substances.

[0152] Furthermore, because established chemical substances exist in the literature for modifying the metal composition of MOFs, sufficient expertise in the art should enable the production of NU-1000-related MOFs containing cheaper metal components, such as zirconium metal precursors with a purity of only 90% and containing hafnium. In fact, one embodiment was tested in this invention, in which the NU-1000 MOF analog contained a 9:1 Zr:Hf ratio within the node composition. In experiments similar to those specified above regarding NU-1000 itself, it was found that the 90% Zr / 10% Hf MOF did indeed exhibit similarly excellent nodal absorption of selenium-source oxygen anions (i.e., 90% to up to 95% absorption was seen with pure Zr NU-1000 MOF), implying that manufacturing NU-1000 using lower-purity zirconium feedstock should reduce commercial costs.

[0153] Furthermore, since it is known that those skilled in the art should generally be able to devise regeneration procedures for anion removal media treated with acid, such as, but not limited to, hydrochloric acid, sulfuric acid, or nitric acid washes, to recover previously used removal media for reuse, thereby reducing overall operating costs, those skilled in the art should be able to subject MOFs to similar acid washing techniques to regenerate NU-1000, which, once saturated with oxygen-containing anion impurities, can be reused, thus reducing the total cost of water treatment operations using MOFs to a point of economic viability.

[0154] It should also be understood that the MOFs of the present invention, with linked ligands for cation complexation, can be used in various environments or industries where the removal of cationic substances is required, because the ability to reduce the concentration of large cations in a given liquid solution or stream can have a variety of beneficial effects. For example, reducing lead (Pb) in a given liquid stream. 2+ The concentration of [a certain substance] can reduce stress corrosion cracking in some materials in which the liquid stream comes into contact. Furthermore, the removal of certain cationic substances (such as cationic lead and mercury) can provide health and environmental benefits. Given that the drinking water lead limit can be as low as 10 ppb, this invention provides the ability to remove lead from a given liquid stream to such permissible levels.

[0155] This invention also describes a method for attaching MOFs to a substrate to form a product containing MOFs, the product of which can be used in various ways depending on the specific MOF attached to the substrate. Therefore, it should be understood that, in order to attach to a substrate, a specific MOF with specific properties can be selected, such as affinity for a specific substance to be removed from a given fluid. The substrate can be any substrate to which a given MOF can be attached, and the form and shape of the substrate can be selected based on its end use. For example, the structure or shape of the substrate can be selected to allow the use of the selected MOF in a given environment (e.g., a given industrial process or a given equipment component) and to provide appropriate MOF exposure in that environment, such as MOF exposure to a given fluid in a given process or equipment component. It should be understood that although MOF is generally referred to in the singular herein, it should also be understood appropriately to refer to multiple MOF particles, as opposed to a single MOF particle or structure. For example, a description of the mechanism for attaching MOFs to a substrate can be interpreted as a mechanism for attaching a single MOF particle; however, it should be understood that in MOF attachment to a substrate, multiple MOF particles are obviously attached to a given substrate.

[0156] Therefore, the present invention provides a method for arranging a given MOF on a substrate to form a commercial product. The present invention also provides a method for using that commercial product in a given process to remove certain chemicals or compounds from a fluid (e.g., a liquid or liquid stream or a gas or gas stream). The following description of these methods, including MOFs and substrates that can be used in the present invention, should be noted. It should be noted that these are exemplary and are not intended to represent the only MOFs or substrates that can be used, or the only way in which a substrate product containing MOFs can be used.

[0157] As mentioned above, the MOF can be any MOF described herein. For example, an MOF can be one capable of or configured to remove certain chemicals or compounds from a liquid or liquid stream, such as an industrial process liquid stream. In some embodiments, the MOF is a Zr-based MOF or a zinc-based MOF. In some embodiments, the MOF is a Zr-based MOF, such as a MOF having the molecular formula Zr6(μ3-O)4(μ3OH)4(OH)4(H2O)4(TBAPy)2, wherein TBAPy is 1,3,6,8-tetra(para-benzoic acid)pyrene, with or without certain linked ligands. This MOF has been shown to remove selenium-containing oxyanions, including selenite (SeO3). 2- ) and selenate (SeO4) 2- Antimony oxoanions, including Sb[III] (antimony) or Sb[V] (antimony) redox states; and lead oxoanions, including Pb[II] or Pb[IV] redox states, such as Pb(OH)6. 2- Pb(OH)6 4-PbO3 2- and PbO2 2- It should be understood that in some embodiments, the MOF adsorbs oxygen-containing anions via nodal absorption through the zirconium oxide / hydroxide node portion of the MOF. U.S. Patent Application Publication No. US2016 / 0318773 A1, entitled "Metal-Organic Frameworks for Adsorption of Liquid Phase Compounds," and U.S. Patent Application Publication No. US2018 / 0134581 A1, entitled "Metal-Organic Frameworks for Adsorption of Liquid Phase Compounds," describe such specific MOFs, including their synthesis and uses, and are each incorporated herein by reference in their entirety.

[0158] Furthermore, adding certain ligands to this MOF provides the removal of certain cationic substances, such as divalent lead (Pb). 2+ ) or mercury (Hg 2+ It contains cations and similar cations, and provides the ability to remove both cationic and anionic substances from a given liquid or liquid stream simultaneously. In some embodiments, the ligand attached to the MOF for complexing with the cationic substance is a thiosulfonyl-thiol (-SO2-S-R2-SH, where R2 is an alkyl group, which can be ethyl or propyl) ligand, also known as a thio-alkyl-sulfonyl-thiol ligand.

[0159] The ligand can be attached to a side group of the MOF (e.g., a side benzyl group to which the sulfonyl (i.e., -SO2-) functional group of the ligand is attached). In some embodiments, the side group is attached to a linking group of the MOF. It should be understood that multiple side groups can be used, each attached to a separate linking group of the MOF. It should also be understood that the sulfonyl group attached to the MOF allows the thioalkyl group to be attached to the sulfonyl group on the MOF via nucleophilic attack. Therefore, any side group to which the sulfonyl group can be attached and which itself can be nucleophilically attacked can be used to attach the ligand of the present invention to the MOF. In some embodiments, the side group can be a side benzyl group.

[0160] It should be understood that suitable side groups can be attached to the linking group moiety of a MOF using solvent-assisted linker exchange (SALE) or solvent-assisted ligand binding (SALI) (see, for example, P. Deria, W. Bury, J. Thuupp and OK Farha, “Versatile Functionalization of the NU-1000 Platform by Solvent-Assisted Ligand Incorporation”, Chem. Commun. 2014, 50, 1965-1068; and P. Deria, J. E. Mondloch, O. Karagiardi, W. Bury, J. Thuupp and OK Farha, “Beyond Post-Synthesis Modification: Evolution of Metal-Organic Frameworks via Building Block Replacement,” Chem. Soc. Rev. 2014, 43, 5896-5912). Therefore, side benzyl groups can be attached to various sites on the MOF, including the organic linking group moiety, using SALE or SALI. In one embodiment, a side benzyl group (e.g., [MOF]-HC=C-CH-phenyl) can be generated by attaching a phenyl group to the linking group portion of the MOF via a styrene bond. In some embodiments, the side benzyl group can be arranged within or inside the MOF structure, for example, in the middle or near the middle of the MOF, rather than arranging the side benzyl group adjacent to the pores of the MOF structure using SALI in some embodiments.

[0161] Regarding the complexation of cationic substances with ligands linked to the MOF for complexation with the cationic substances, it should be understood that an important aspect of the ligand is the synthesis of the -SO2-S- bond, i.e., the SS bond between the thioalkyl and sulfonyl moieties. This provides ligands with a thiosulfonyl moiety and a terminal thiol moiety (-SH). As described below, cations (such as lead) are complexed through disulfide interactions with the ligand, wherein the lead cation (Pb) 2+ It complexes with the thiosulfonyl moiety of the thiosulfate group and also with the terminal thiol moiety (-SH), which essentially "bites back" the lead cation (Pb). 2+ This forms a five- or six-membered open-ring or cyclic geometry, depending on whether the R2 alkyl group is ethyl or propyl. The complexation of the cation with the ligand can also be termed ion interaction or chemisorption, which occurs through the positive charge on the cation and the electronegativity of the thiosulfonyl moiety and the terminal thiol moiety. Therefore, it should be understood that the ligands of the present invention can be used to complex cations other than lead. For example, with lead (Pb... 2+Similar cations, such as cationic mercury, can be complexed in a similar manner.

[0162] However, it should be understood that other MOFs can be used and attached to a given substrate. For example, an MOF can be a Zr-based MOF used to remove certain chemicals, such as water, from a gas stream or air (including ambient air). Such MOFs may include MOF-801, 801-P, 802, 805, 806, 808, 812, and 841. In some embodiments, such MOFs, once attached to a given substrate, can be used to remove water from ambient air at night and efficiently generate liquid water using solar energy during the day without consuming electricity. These MOFs are described in Hiroyasu Furukawa, Felipe Gandara, Yue-Biao Zhang, Juncong Jiang, Wendy L. Queen, Matthew R. Hudson, and Omar M. Yaghi, “Water Adsorption in Porous Metal-Organic Frameworks and Related Materials”, J. Am. Chem. Soc. 136, 4369-4381 (2014), which is incorporated herein by reference in its entirety.

[0163] It is also mentioned that the substrate can be any substrate to which a given MOF can be attached and is suitable for use in an environment or process for removing certain chemicals or compounds from a liquid or liquid stream. In some embodiments, the substrate can be an inert substrate to avoid any chemical interaction with the liquid or liquid stream being treated. In some embodiments, the substrate has a physical shape that allows it to be arranged and used in a given process or in a particular processing device to remove certain chemicals from a given liquid stream. In some embodiments, the substrate can be beads or multiple beads. In some embodiments, the beads can be inert polypropylene polymer resin beads. In some embodiments, the substrate can be a macro-woven fabric, such as a screen material or screen filter. In some embodiments, the substrate can be a molecular fabric made of organic strands, which are essentially composed of a two-dimensional copolymer skeleton or organic woven material.

[0164] It should be understood that the following description of methods for attaching a given MOF to a substrate, and the description of methods for using a substrate with an attached MOF, generally refers to MOFs. However, it should be understood that the specific MOFs mentioned above can be used in all embodiments described herein. Therefore, it should be understood that while some of the above-mentioned specific MOFs are capable of removing or configured to remove specific liquid-phase cations and anions, other MOFs capable of removing other liquid-phase substances from a liquid or liquid stream can be similarly used and attached to a given substrate. Furthermore, while some of the above-mentioned specific MOFs are capable of removing certain substances from a gas or gas stream, such as water from ambient air, other MOFs capable of removing other gaseous substances from a gas or gas stream can be similarly used and attached to a given substrate. (It should be understood that the terms "gas" or "gas stream" are used generally and include any gas or gas stream containing condensable substances or entrained vapors or particles.) Moreover, while the following methods are described with respect to specific substrates, it should be understood that other substrates, including substrates with different chemical compositions or different geometries, can be used in combination with any suitable MOF.

[0165] Typically, the method for attaching a given MOF particle to a substrate may depend on the specific substrate used. Therefore, the following describes methods for attaching a given MOF to beads (including multiple beads), macro-fabrics (e.g., screen fabrics or screen filters), and molecular fabrics made of organic strands (consisting essentially of a two-dimensional copolymer skeleton or organic woven material).

[0166] In some embodiments, a given MOF can be attached to a substrate as beads or multiple beads. In some embodiments, the beads can be inert polypropylene polymer resin beads. Typically, the method for attaching MOFs uses a buffer modifier that attaches the MOF to the bead surface. In some embodiments, the buffer modifier can be a buffer modifier commonly used in capillary electrophoresis, such as a permeation flow modifier, including cetyltrimethylammonium bromide (CTAB) and β-cyclodextrin (β-CD). Both CTAB and β-CD are compounds that fully bind to the MOF particles at room temperature and cause the MOF to be chemisorbed onto the bead surface.

[0167] In one embodiment, CTAB can be used to attach MOFs to the bead surface. In this case, beads with a metal oxide are seeded using atomic layer deposition (ALD), which provides surface hydroxyl groups capable of forming chemical bonds with the MOF particles via CTAB. In some embodiments, the metal oxide is chemisorbed onto the bead surface in water, thereby making the hydroxyl groups available for attachment to CTAB via, for example, the cationic heads of CTAB. These metal oxides include, but are not limited to, alumina, titanium oxide, zinc oxide, and combinations thereof. Once exposed to water, the deposited metal oxide appears to resemble silica / surface hydroxide in the capillary electrophoretic permeation flow reverse application of CTAB. Thus, the MOF is then attached to CTAB via hydrogen bonding, electrostatic interactions, and van der Waals forces. Without being theoretically limited, it is believed that the nonpolar surface of the MOF, such as the organic linking groups of the MOF, is attached to the trimethyl "arm" of the CTAB.

[0168] In one embodiment using CTAB, the beads are first subjected to an ALD (Alternating Current Deposition) to allow the metal oxide to be chemisorbed onto the surface of the beads. CTAB and MOF can be combined individually at room temperature to allow the MOF to attach to the CTAB, forming a solution of CTAB with the MOF attached. The beads with the attached metal oxide can then be contacted with the solution, or combined with CTAB having the attached MOF, so that the CTAB is again attached to the bead surface via the metal oxide. This can be done in an aqueous solution at room temperature, and in some embodiments in an alkaline aqueous solution. Alternatively, the beads after undergoing ALD to attach the metal oxide can be mixed in an aqueous solution containing the MOF, and in some embodiments, in an alkaline aqueous solution containing the MOF. Subsequently, CTAB can be added to the solution to attach to both the MOF and the metal oxide, thereby attaching the MOF to the bead surface. Afterward, the beads can be washed and dried. Thus, beads with adsorbed MOF, such as multiple polypropylene beads with adsorbed MOF, have been produced. These beads can constitute a commercial product and their use can be further described below.

[0169] In another embodiment, β-CD can be used to attach the MOF to the bead surface. In this case, it is not necessary to pass the substrate through ALD. Instead, the nonpolar regions of the β-CD will be attached to the corresponding nonpolar portions of the polypropylene beads via hydrogen bonds, electrostatic interactions, and van der Waals forces. The MOF can then be attached to the β-CD via the interaction between one or more polar portions on the MOF surface and the negative charge on the β-CD. In some embodiments, the MOF can be attached to the beads in an aqueous solution containing β-CD. In some embodiments, a less polar solvent, such as an alcohol, can be used. The beads can then be washed and dried. Thus, MOF-adsorbed beads, such as multiple MOF-adsorbed polypropylene beads, have been produced, which can constitute a commercial product and can be used as further described below.

[0170] It should be understood that in some embodiments, β-CD and CTAB can be used in combination. In this case, the substrate or beads will be passed through ALD, followed by the addition of a solution containing MOF as well as both CTAB and β-CD.

[0171] It should also be understood that, in some embodiments, the surface of the beads used for CTAB and β-CD functionalization may be silica. In some cases, the polymer beads may be functionalized with silane hydroxide chemicals to accept silicon adducts, followed by hydroxides, to provide the chemicals necessary for the bonding of CTAB or β-CD.

[0172] In another embodiment, the invention includes a method for attaching MOFs to a macro-fabric for subsequent use. In some embodiments, the macro-fabric can be any fabric to which a given MOF can be attached, including materials based on synthetic fibers. In some embodiments, the macro-fabric is a screen material or screen filter, including inert polypropylene-based screen materials or filters. Therefore, it should be understood that the fabric can have any size, such as any area or surface area, depending on the needs or requirements of the fabric's end use. MOF particles can be attached to the fibers of the fabric in the same manner as described above regarding attachment to beads. Therefore, it should be understood that buffer modifiers, such as β-CD and CTAB, can be used as described above to combine with the fabric's ALD treatment to attach the MOFs to the fabric. After the MOFs are attached to the macro-fabric, macro-fabricated fabrics with adsorbed MOFs have been produced, which can constitute commercial products and can be used as further described below. It should be understood that the term "macro" is used to distinguish the fabric from fabrics that are visible to the naked eye or can be physically manipulated by hand, as opposed to molecular fabrics as described below.

[0173] In another embodiment, the invention includes a method for attaching MOFs to molecular fabrics for subsequent use. In some embodiments, the molecular fabric is made of organic strands to which a given MOF can be attached, the organic strands essentially forming a two-dimensional copolymer skeleton or organic woven material. MOF particles can be attached to the strands of the fabric in the same manner as described above regarding attachment to beads. Therefore, it should be understood that buffer modifiers, such as β-CD and CTAB, can be used as described above to combine with the ALD treatment of the fabric to attach the MOFs to the fabric. After the MOFs are attached to the molecular fabric, MOF-adsorbed molecular fabrics have been produced, which can constitute commercial products and can be used as further described below. It should be understood that molecular fabrics are fabrics formed at the molecular level, and therefore their dimensions are much smaller than, for example, the macroscopic fabrics described above.

[0174] Once connected, a substrate with a connected MOF can be used to remove certain chemicals from a liquid or liquid stream, such as an industrial liquid stream (e.g., a power plant coolant stream, like a nuclear power plant stream) or a waste stream. Typically, the substrate with the connected MOF is arranged to allow contact between the liquid containing one or more liquid substances to be removed from the liquid and the MOF. Upon contact, the liquid substance to be removed will connect to the MOF and thus be removed from the liquid. In this respect, the manner in which a substrate with a connected MOF is used depends on the specific MOF being connected, the liquid phase substance it can remove, and the physical structure of the inert substrate used (e.g., beads or fabric).

[0175] Regarding the beads, this can be used in the same way as conventional resin beads to remove certain chemicals from liquids, for example, by placing the beads in a resin bed in a given container through which the liquid to be treated will pass. It should be understood that existing equipment designed for controlling resin beads can be modified if it is necessary to control the use of beads coated with MOF particles. In one embodiment, a cylindrical container containing a bed of beads coated with MOF particles can be used. In this case, the bead bed is fixed within the container, and a liquid flow is made through the container, passing through the bead bed and providing contact between the liquid containing the liquid substance to be removed and the MOF particles. Upon contact, the liquid substance to be removed will bind to the MOF, thereby being removed from the liquid passing through the container.

[0176] It should be understood that in some embodiments where the container contains resin beads for removing certain liquid phase substances, such resin beads can be replaced with beads coated with a given MOF according to the present invention. In one embodiment, when resin beads need to be replaced, they can be easily replaced within the same device with beads coated with a given MOF according to the present invention. Alternatively, inert polypropylene beads can be used instead of resin beads, and the selected MOF can be bonded in situ. In such a case, the beads can be pretreated with ALD to bond the given metal oxide before being placed in the container, or they can be treated in situ with ALD to bond the metal oxide. In the latter case, the beads are placed in the container and then treated with ALD to bond the metal oxide. Subsequently, a solution containing CTAB and the selected MOF can be added to the container to bond the CTAB and MOF to the beads, or a solution of CTAB can be added to the container followed by a solution of the selected MOF. The result is that the original resin beads are replaced with beads coated with the selected MOF without any changes or modifications to any existing equipment used for the original resin beads.

[0177] Alternatively, the beads are placed in a container, and then a solution containing β-CD and a selected MOF can be added to the container to attach the β-CD and MOF to the beads. Alternatively, a solution of β-CD can be added to the container, followed by a solution of the selected MOF. The result is that the original resin beads are replaced with beads coated with the selected MOF without requiring any changes or modifications to any existing equipment used for the original resin beads.

[0178] In the case of a macroscopic fabric coated with a selected MOF, the fabric can be positioned such that a liquid flow will pass through it, thereby providing contact between the liquid containing the liquid substance to be removed and the MOF particles attached to the fabric fibers. Upon contact, the liquid substance to be removed will attach to the MOF, thus being removed from the liquid passing through the fabric. It should be understood that the fabric can be placed inside a container or pipe or any equipment component to allow liquid to pass through it.

[0179] In one embodiment, a softener through which liquid flows can be used. In this case, the macro-fabric can be a screen filter, which can be wound into a spiral shape to form an inner cavity at the center. Liquid can be introduced into the softener and pass around the outside of the wound screen filter. The liquid will then pass through the wound screen filter and into the inner cavity or center of the softener, and flow out through the center of the softener. It should be understood that in some embodiments, the existing screen filter can be coated with a selected MOF. In this case, the MOF can be attached in situ to the existing screen filter in the same manner as described above regarding the in-situ coating of beads in an existing container.

[0180] It should also be understood that MOF-coated fabrics can be used in many different situations. In one embodiment, MOF-coated fabrics can be used on top of a resin bed to facilitate the removal of liquid phase substances, thereby removing other liquid phase substances, or additionally, the same or similar substances, relative to those removed by the resin bed. Additionally, it should be understood that in embodiments where the bead bed is in-situ coated with a selected MOF, a macro-fabric can also be in-situ coated with the selected MOF on top of the bed, while simultaneously utilizing the bead bed coating. Therefore, it should also be understood that the MOFs used for the beads and the fabric can be the same or different, and it should be noted that if they are different, it may be necessary to coat either the beads or the fabric before placing both into a given container.

[0181] In the case of a molecular fabric coated with a selected MOF, such a fabric can be positioned or placed such that a liquid flow will pass through it, thereby providing contact between the liquid containing the liquid substance to be removed and the MOF particles attached to the fabric fibers. Upon contact, the liquid substance to be removed will attach to the MOF, thus being removed from the liquid passing through the fabric. It should be understood that the fabric can be placed inside a container, pipe, or any device to allow liquid to pass through it. It should also be understood that the molecular fabric can be generated in situ and subsequently attached to the selected MOF particles. In some embodiments, the molecular fabric can be constructed such that it is located at the outlet of a container, such as a container containing resin beads in a bed or softener.

[0182] However, regardless of the substrate used, it should be understood that, for a given liquid flow and the concentrations of various liquid phase components to be removed, the selected MOF will typically have a much greater capacity to remove those components, making MOF saturation not a limiting factor. Therefore, instead of using, for example, a bed filled with MOF particles, using a substrate coated with MOF particles will still provide the necessary surface area to obtain the given liquid phase substance to be removed.

[0183] Various embodiments of the present invention have been described above. However, it should be understood that alternative embodiments are possible, and the present invention is not limited to the specific embodiments described above.

Claims

1. A product comprising a compound and a substrate, wherein the compound is for complexing with a liquid phase oxyanion and a liquid phase cation and has the formula R1-S02-S-R2-SH, wherein R1 comprises a zirconium metal organic framework and R2 comprises an alkyl group; and the compound is attached to the substrate.

2. The product of claim 1, wherein the metal organic framework comprises NU-1000.

3. The product of claim 1, wherein R2 comprises an ethyl group or a propyl group.

4. The product of claim 1, wherein R2 comprises an ethyl group.

5. The product of claim 1, wherein R2 comprises a propyl group.

6. The product of claim 1, wherein the substrate comprises inert polypropylene beads.

7. The product of claim 6, wherein the metal organic framework comprises NU-1000 and R2 comprises an ethyl group or a propyl group.

8. The product of claim 1, wherein the substrate comprises a macroscopic fabric.

9. The product of claim 1, wherein the substrate comprises a molecular fabric.

10. A compound further comprising an absorbed liquid phase oxyanion and an absorbed liquid phase cation, comprising: a compound having the formula R1-S02-S-R2-SH, wherein R1 comprises a zirconium metal organic framework and R2 comprises an alkyl group; an absorbed liquid phase oxyanion attached to the compound; and an absorbed liquid phase cation attached to the compound.

11. The compound of claim 10, wherein the zirconium metal organic framework comprises a pendant benzyl group attached to an organic linker, wherein R2 comprises an ethyl group or a propyl group, wherein the absorbed liquid phase oxyanion comprises selenate, and wherein the absorbed liquid phase cation comprises lead.

12. The compound of claim 10, wherein the metal organic framework comprises NU-1000.

13. The compound of claim 10, wherein R2 comprises an ethyl group or a propyl group.

14. The compound of claim 10, wherein R2 comprises an ethyl group.

15. The compound of claim 10, wherein R2 comprises a propyl group.

16. The compound of claim 10, wherein the compound is attached to a substrate.

17. The compound of claim 16, wherein the substrate comprises inert polypropylene beads.

18. The compound of claim 17, wherein the metal organic framework comprises NU-1000 and R2 comprises an ethyl group or a propyl group.

19. The compound of claim 16, wherein the substrate comprises a macroscopic fabric.

20. The compound of claim 16, wherein the substrate comprises a molecular fabric. ​

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