METHOD FOR PREPARING, IN SITU, METAL-ORGANIC FRAMEWORK BY USING CONTROL OF DIFFUSION WITHIN IONIC POLYMER

Abstract

Disclosed is a method for preparing a matrix containing metal-organic frameworks (MOFs), comprising the steps of: 1) mixing an organic ligand precursor solution and an anionic polymer-containing solution to produce a mixed solution; and 2) adding a metal salt to the mixture solution. In addition, the present disclosure provides a matrix containing MOFs prepared according to the preparation method, and an adsorbent comprising the same. Furthermore, a method for performing fluid separation by using a matrix containing MOFs prepared according to the preparation method is disclosed.

Claims

1. A method for preparing a matrix containing metal-organic frameworks (MOFs), the method comprising steps of: 1) mixing an organic ligand precursor solution and an anionic polymer-containing solution to produce a mixed solution; and 2) adding a metal salt to the mixed solution.

2. The method of claim 1, wherein step 1) further comprises step 1-1) of adding a crosslinkable metal salt to the mixed solution.

3. The method of claim 1, further comprising, before step 1): step 1-0) of mixing the anionic polymer and a flexible polymer to produce an anionic polymer-containing solution.

4. The method of claim 1, wherein the MOFs contained in the matrix are uniformly distributed in the matrix.

5. The method of claim 1, wherein the MOFs have windows formed inside the MOFs wherein the windows have a uniform window size.

6. The method of claim 1, wherein the matrix comprises 10 to 50% by weight (wt %) of MOFs based on the total weight of the matrix.

7. The method of claim 1, wherein the anionic polymer is at least one selected from the group consisting of alginate, carboxymethyl cellulose, hyaluronic acid, poly(acrylic acid) (PA) and its derivatives, poly(methyl acrylate) (PMA) and its derivatives, poly(thiophene acetic acid) and its derivatives, poly(sulfonate styrene) (PSS) and its derivatives, and a combination thereof.

8. The method of claim 7, wherein the anionic polymer is alginate.

9. The method of claim 1, wherein the anionic polymer is a substitute polymer having anionic polymer-like properties.

10. The method of claim 9, wherein the substitute polymer having anionic polymer-like properties is an anionic cellulose microfiber.

11. The method of claim 1, wherein the metal salt of step 2) is derived from at least one metal selected from the group consisting of copper (Cu), zinc (Zn), iron (Fe), nickel (Ni), zirconium (Zr), chromium (Cr), scandium (Sc), cobalt (Co), titanium (Ti), manganese (Mn), vanadium (V), aluminum (Al), magnesium (Mg), gallium (Ga), indium (In), yttrium (Y), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag) and cadmium (Cd).

12. The method of claim 1, wherein the organic ligand precursor solution comprises a weak basic material having a pK.sub.b value of 3 to 6.

13. A matrix containing metal-organic frameworks (MOFs), prepared by the method of claim 1.

14. An adsorbent comprising the matrix containing MOFs of claim 13.

15. A method for separating first fluid having a first single molecule size V1 or second fluid having a second single molecule size V2 from a fluid mixture comprising the first fluid and the second fluid (provided that V1≠V2), the method comprising the step of: passing the fluid mixture through a matrix containing metal-organic frameworks (MOFs) prepared by the method of claim 1, wherein the MOFs have adsorption property or a window size that allows the first fluid to pass and does not allow the second fluid to pass therethrough.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] FIG. 1 schematically illustrates a difference between matrix structures generated according to an order of addition of metal and ligands in a method for preparing a metal-organic framework (MOF)-containing matrix of the present disclosure.

[0057] FIG. 2 schematically illustrates a method for preparing a MOF-containing matrix of the present disclosure, according to an order of addition of metal and ligands.

[0058] FIG. 3 illustrates microscopic observation results of a MOF-containing matrix formed in Comparative Example 1 for different reaction times. OM represents an optical microscope result, SEM represents a scanning electron microscope result, and FIG. 3 illustrates a change over time after addition of BTC.sup.3− ions.

[0059] FIG. 4 illustrates microscopic observation results of a MOF-containing matrix formed in Example 1 for different reaction times. OM represents an optical microscope result, SEM represents a scanning electron microscope result, and FIG. 4 illustrates a change over time after addition of Cu.sup.2+ ions.

[0060] FIGS. 5A through 5D illustrate observation results of a membrane prepared in Comparative Example 2, FIG. 5A illustrates the membrane observed with naked eyes, FIG. 5B illustrates an SEM image of a side view of the membrane, and FIGS. 5C and 5D illustrate SEM images of a top view and a bottom view of the membrane, respectively.

[0061] FIGS. 6A through 6D illustrate observation results of a membrane prepared in Example 2, FIG. 6A illustrates the membrane observed with naked eyes, FIG. 6B illustrates an SEM image of a side view of the membrane, and FIGS. 6C and 6D illustrate SEM images of a top view and a bottom view of the membrane, respectively.

[0062] FIG. 7 illustrates SEM images of surfaces and interiors of matrices prepared in Example 3 and Comparative Example 3. MD-MOR74-ALG is a result of Comparative Example 3, and LD-MOR74-ALG is a result of Example 3.

[0063] FIGS. 8A through 8C illustrate magnified SEM images of a matrix prepared in Example 1. FIG. 8A illustrates a region of the matrix near a surface, FIG. 8B illustrates a region of the matrix far from the surface, and FIG. 8C illustrates a core region of the matrix.

[0064] FIG. 9 illustrates results of X-ray diffraction (XRD) of a matrix prepared in Comparative Example 1 for different reaction times.

[0065] FIG. 10 illustrates results of XRD of the matrix prepared in Example 1 for different reaction times.

[0066] FIG. 11 illustrates results of XRD of the membrane prepared in Comparative Example 2 and a polymer membrane that does not contain a MOF.

[0067] FIG. 12 illustrates results of XRD of the membrane prepared in Example 2.

[0068] FIG. 13 illustrates results of XRD of the matrices prepared in Example 3 and Comparative Example 3 and crystals of Preparation Example 2.

[0069] FIG. 14 illustrates results of SEM measurement and EDS analysis of the matrix prepared in Example 1 for different reaction times.

[0070] FIGS. 15A through 15D illustrate absorbance of methylene blue and rhodamine 6G with respect to UV-visible light. FIGS. 15A and 15B illustrate absorption spectra for different concentrations of the methylene blue and rhodamine 6G, respectively, and

[0071] FIGS. 15C and 15D illustrate absorbance for different concentrations of the methylene blue and rhodamine 6G at λmax, respectively.

[0072] FIGS. 16A through 16F illustrate absorbance of Cu.sup.2+ ALG spheres before ligands are added in Comparative Example 1 with respect to methylene blue and rhodamine 6G, and absorbance of Ca.sup.2+ ALG spheres before copper ions are added in Example 1 with respect to methylene blue and rhodamine 6G. FIGS. 16A and 16D illustrate absorption spectra of the Ca.sup.2+ ALG spheres before copper ions are added in Example 1 with respect to methylene blue and rhodamine 6G over time, FIGS. 16B and 16E illustrate absorption spectra of the Cu.sup.2+ ALG spheres before ligands are added in Comparative Example 1 with respect to methylene blue and rhodamine 6G over time, and FIGS. 16C and 16F illustrate a change in concentration over time at λmax of each of methylene blue and rhodamine 6G.

[0073] FIGS. 17A through 17I illustrate absorbance of spheres LD-HK-ALG of Comparative Example 1 and spheres MD-HK-ALG of Example 1 with respect to methylene blue and rhodamine 6G. FIGS. 17A and 17D illustrate absorption spectra of the spheres MD-HK-ALG of Example 1 with respect to methylene blue and rhodamine 6G over time, respectively, FIGS. 17B and 17E illustrate absorption spectra of the spheres LD-HK-ALG of Comparative Example 1 with respect to methylene blue and rhodamine 6G over time respectively, FIG. 17C illustrates changes in concentrations of the spheres MD-HK-ALG of Example 1 and the spheres LD-HK-ALG of Comparative Example 1 over time at λmax of methylene blue, and FIG. 17F illustrates changes in concentrations of the spheres MD-HK-ALG of Example 1 and the spheres LD-HK-ALG of Comparative Example 1 over time at λmax of rhodamine 6G. FIG. 17G illustrates absorption spectra of the spheres MD-HK-ALG of Example 1 with respect to both methylene blue and rhodamine 6G over time, FIG. 17H illustrates absorption spectra of the spheres LD-HK-ALG of Comparative Example 1 with respect to both methylene blue and rhodamine 6G over time, and FIG. 17I illustrates changes in concentrations of the spheres MD-HK-ALG of Example 1 and the spheres LD-HK-ALG of Comparative Example 1 over time at λmax of methylene blue and rhodamine 6G.

[0074] FIG. 18A illustrates a window size of HKUST-1 crystals, FIG. 18B illustrates a molecular size and a molecular structure of methylene blue, and FIG. 18C illustrates a molecular size and a molecular structure of rhodamine 6G.

[0075] FIG. 19 illustrates results of XRD of HKUST-1 crystals of Preparation Example 1, and spheres of Example 1 before and after adsorption of methylene blue and rhodamine 6G.

[0076] FIGS. 20A and 20B illustrate results of thermogravimetric analysis (TGA) of spheres of Comparative Example 1 and the spheres of Example 1, respectively. FIG. 20A illustrates the result of the spheres of Example 1, and FIG. 20B illustrates the result of the spheres of Comparative Example 1.

BEST MODE FOR CARRYING OUT THE INVENTION

[0077] Hereinafter, the present disclosure will be described in more detail with reference to the following examples. However, these examples are provided only for illustration of the present invention, and it should not be construed as limiting the scope of the present invention to these examples.

[0078] Throughout the present specification, “%” used to indicate a concentration of a specific material refers to % by weight/weight for solid/solid, % by weight/volume for solid/liquid and % by volume/volume for liquid/liquid, unless otherwise stated.

[0079] Materials Used

[0080] The following materials were used in examples and comparative examples. [0081] Copper (II) nitrate hemipentahydrate (Cu(NO.sub.3).sub.2.2.5H.sub.2O): purity of 98.0 to 102%, manufactured by Alfa Aesar. [0082] Trimesic acid (1,3,5-bezenetricarboxylic acid, H.sub.3BTC): purity of 95%, manufactured by Aldrich. [0083] Triethylamine (TEA): purity of 99%, manufactured by Alfa Aesar [0084] Ethanol (EtOH): purity of 94.5%, manufactured by Daejung. [0085] Acetone (ACT): purity of 99.5%, manufactured by Daejung. [0086] Zinc (II) nitrate hexahydrate (Zn(NO.sub.3).sub.2.6H.sub.2O): purity of 99%, manufactured by Aldrich. [0087] 2,5-Dihydroxyterephthalic acid (H.sub.4DOBDC): purity of 97%, manufactured by Alfa Aesar. [0088] Methanol (MeOH): purity of 99.5%, manufactured by Daejung. [0089] Sodium alginate (Na.sup.+ALG, CAS number 9005-38-3, LOT number MKBX6322V): manufactured by Sigma Aldrich. [0090] Ca(NO.sub.3).sub.2.4H.sub.2O (calcium nitrate tetrahydrate): purity of 99%, manufactured by Aldrich. [0091] Methylene blue (MB, LOT Number 10187938): manufactured by Alfa Aesar. [0092] Rhodamine 6G (R6G) purity: 99%, manufactured by Aldrich. [0093] Poly(vinyl alcohol) (PVA, Mw 89,000-98,000): manufactured by Aldrich. [0094] Deionized distilled water (DDW): purified and manufactured by a purification system (MQ Direct 8 of Merck Millipore).

[0095] All solvents were distilled and purified with zeolite 4A in a moisture-free argon-charged glove box. All synthesized samples were also stored in the moisture-free argon-charged glove box prior to use.

Preparation Example 1: Preparation of Pristine HKUST-1 Powder

[0096] To a vial, 10 mL of DDW and Cu(NO.sub.3).sub.2.2.5H.sub.2O (0.87 g, 3.7 mmol) were added. To another vial, 10 mL of ethanol was added and H3BTC (0.22 g, 1.0 mmol) and TEA (0.30 g, 3.0 mmol) were added, to prepare deprotonated H.sub.3BTC (BTC.sup.3−). A Cu(NO.sub.3).sub.2 solution was added to a BTC.sup.3− solution, followed by continuous stirring at room temperature for 3 hours (h). Subsequently, washing with ethanol was performed, to obtain a crystalline solid. All processes were performed at room temperature.

Preparation Example 2: Preparation of MOF-74(Zn) Powder

[0097] To a flask, 10 mL of DDW and Zn(NO.sub.3).sub.2.6H.sub.2O (0.59 g, 2.0 mmol) were added. In another flask, 10 mL of DDW was added and H.sub.4DOBDC (0.20 g, 1.0 mmol) and TEA (0.40 g, 4.0 mmol) were added, to prepare deprotonated H.sub.4DOBDC (DOBDC.sup.4−). A Zn(NO.sub.3).sub.2.6H.sub.2O solution was added to a DOBDC.sup.4− solution, followed by continuous stirring at room temperature for 3 h. Subsequently, washing with a mixture of water and methanol was performed, to obtain a crystalline solid. All processes were performed at room temperature.

Comparative Example 1: Preparation of HK-ALG Spheres Via BTC.SUP.3− Ligand Dispersion (LD-HK-ALG)

[0098] An aqueous 5.0 wt % Na.sup.+ALG solution (0.5 ml) was dropped into a 0.5 M Cu(NO.sub.3).sub.2 solution (5 ml) using a Pasteur pipette. The drops immediately became turquoise blue spherical solids (see FIG. 3). Then, the above immersion was kept for 30 min to fully exchange Na.sup.+ ions with Cu.sup.2+ ions (hereinafter, referred to as “Cu.sup.2+ALG”). Subsequently, the Cu.sup.2+ALG spherical solids were washed by immersing them into ethanol for 10 min, and this process was repeated 5 times to completely replace remaining water, to facilitate drying.

[0099] A 0.5 M BTC.sup.3− solution (5 mL) was prepared by mixing H.sub.3BTC and TEA with 1-to-3 stoichiometry in a 1:1 mixture of H.sub.2O and EtOH. After drying of the Cu.sup.2+ ALG spherical solids for 1 h, the Cu.sup.2+ALG spherical solids were immersed into the 0.5 M BTC.sup.3− solution. BTC.sup.3− ligands were allowed to react with Cu.sup.3+ in the Cu.sup.2+ALG. The reaction was conducted at room temperature, and changes during the reaction were observed every 5, 10, 20, 30, and 60 min after the reaction. Results thereof were shown in FIG. 3.

Example 1: Preparation of HK-ALG Spheres Via Cu.SUP.2+ Ion Dispersion (MD-HK-ALG)

[0100] An aqueous 0.5 M BTC.sup.3− solution was prepared by mixing H.sub.3BTC and TEA with 1-to-3 stoichiometry in distilled water. A BTC.sup.3−-containing Na.sup.+ALG solution was prepared by mixing 1 ml of the aqueous 0.5 M BTC.sup.3− solution and 9 mL of an aqueous 5.0 wt % Na.sup.+ALG solution. Subsequently, the BTC.sup.3−-containing Na.sup.+ALG solution was dropped into a 0.5 M Ca(NO.sub.3).sub.2 solution using a Pasteur pipette. The drops immediately became white solid spheres (see FIG. 4). Subsequently, the above immersion was kept for 30 min to fully exchange Na.sup.+ ions with Ca.sup.2+ ions (hereinafter, referred to as “Ca.sup.2+ALG”). To sufficiently fill the spheres with BTC.sup.3− ligands, immersion of the spheres into a 0.1 M BTC.sup.3− solution was repeated 3 times.

[0101] A 0.5M Cu(NO.sub.3).sub.2 solution was prepared in a 1:1 mixture of H.sub.2O and ACT. After drying of the spheres for 1 h, the spheres were immersed into the 0.5M Cu(NO.sub.3).sub.2 solution (5 mL). BTC.sup.3− ligands in the Ca.sup.2+ ALG were allowed to react with Cu.sup.2+. The reaction was conducted at room temperature, and changes during the reaction were observed every 5, 10, 20, 30, and 60 min after the reaction. Results thereof were shown in FIG. 4.

Comparative Example 2: Preparation of HK-(ALG+PVA) Membrane Via BTC.SUP.3− Ligand Dispersion (LD-HK-(ALG+PVA)^M.)

[0102] A mixed polymer solution was prepared by mixing 5.0 wt % Na.sup.+ALG (5 mL) and a PVA solution (20 mL). The mixed polymer solution was dropped and spread on a flat glass plate with a dimension of approximately 15×15 cm.sup.2. Subsequently, a 0.5 M Cu(NO.sub.3).sub.2 solution was sprayed onto the plate using a spray gun. The spraying was performed for 30 min to allow Na.sup.+ ions of a Na.sup.+ALG polymer chain to be exchanged with Cu.sup.2+ ions and to be crosslinked. After washing with ethanol, an obtained elastic polymer membrane was dried under ambient conditions at room temperature for 1 h.

[0103] A 0.5 M BTC.sup.3− solution was prepared by mixing H.sub.3BTC and TEA with 1-to-3 stoichiometry in DDW. The elastic polymer membrane was immersed into the 0.5 M BTC.sup.3− solution to allow BTC.sup.3− ligands to react with Cu.sup.2+ ions. The reaction was conducted at room temperature for 30 min. After washing with DDW, the membrane was dried under ambient conditions at room temperature, and cut into a size of 4×6 cm.sup.2 prior to use.

Example 2: Preparation of HK-(ALG+PVA) Membrane Via Cu.SUP.2+ Ion Dispersion (MD-HK-(ALG+PVA)m)

[0104] An aqueous 0.5 M BTC.sup.3− solution was prepared by mixing H.sub.3BTC and TEA with 1-to-3 stoichiometry in distilled water. A BTC.sup.3-containing Na.sup.+ALG solution was prepared by mixing 5 ml of the aqueous 0.5 M BTC.sup.3− solution and 5 ml of an aqueous 5.0 wt % Na.sup.+ALG solution. In a separate vial, an aqueous 5.0 wt % PVA solution was prepared by dissolving PVA powder in DDW. The aqueous 5.0 wt % PVA solution was continuously stirred at 80° C. for 6 h to completely dissolve the PVA powder. The PVA solution was added to the BTC.sup.3-containing Na.sup.+ALG solution, and the mixed solution was dropped and spread on a flat glass plate with a dimension of approximately 15×15 cm.sup.2. Subsequently, a 0.5 M Ca(NO.sub.3).sub.2 solution was sprayed onto the plate using a spray gun for 30 min. To sufficiently include BTC.sup.3− ligands in the membrane, an obtained elastic polymer membrane was immersed into a 0.5 M BTC.sup.3− solution, and this process was repeated two or more times. After slightly washing with DDW, the membrane was dried at room temperature for 1 h.

[0105] A 0.5 M Cu(NO.sub.3).sub.2 solution was prepared by dissolving Cu(NO.sub.3).sub.2 in a 1:1 mixture of H.sub.2O and ACT. The membrane was immersed into the 0.5 M Cu(NO.sub.3).sub.2 solution at room temperature for 30 m, to allow BTC.sup.3− ligands in the membrane to react with Cu.sup.2+ ions. After washing with DDW, the membrane was dried under ambient conditions at room temperature, and cut into a size of 4×6 cm.sup.2 prior to use.

Comparative Example 3: Preparation of MOF-74(Zn)-ALG Spheres via DOBDC.SUP.4− Ligand Dispersion (LD-MOF74-ALG)

[0106] An aqueous 5.0 wt % Na.sup.+eLG solution was dropped into a 0.5 M Zn(NO.sub.3).sub.2 solution using a Pasteur pipette. The drops immediately became white spherical solids. Subsequently, the above immersion was kept for 30 min to fully exchange Na ions with Zn.sup.2+ions (hereinafter, referred to as “Zn.sup.2+ALG”). Subsequently, the Zn.sup.2+ALG spherical solids were washed by immersing them into ethanol for 10 min, and this process was repeated 5 times to completely replace remaining water, to facilitate drying.

[0107] A 0.5 M DOBDC.sup.4− solution was prepared by mixing H.sub.4DOBDC and TEA with 1-to-4 stoichiometry in a 1:1 mixture of H.sub.2O and EtOH. After drying of the Zn.sup.2+ALG spherical solids for 1 h, the Zn.sup.2+ALG spherical solids were immersed into the 0.5 M DOBDC.sup.4− solution. DOBDC.sup.4− ligands were allowed to react with Zn.sup.2+in the Zn.sup.2+ALG. The was conducted at room temperature for 30 min.

Example 3: Preparation of MOF-74(Zn)-ALG Spheres Via Zn.SUP.2+ Ion Dispersion (MD-MOF74-ALG)

[0108] An aqueous 0.5 M DOBDC.sup.4− solution was prepared by mixing H.sub.4DOBDC and TEA with 1-to-4 stoichiometry in distilled water. A DOBDC.sup.4−-containing Na.sup.+ALG solution was prepared by mixing 1 ml of the aqueous 0.5 M DOBDC.sup.4− solution and 9 ml of an aqueous 5.0 wt % Na.sup.+ALG solution. Subsequently, the DOBDC.sup.4−-containing Na.sup.+ALG solution was dropped into a 0.5 M Ca(NO.sub.3).sub.2 solution using a Pasteur pipette. The drops immediately became yellow solid spheres. Subsequently, the above immersion was kept for 30 min to fully exchange Na.sup.+ ions with Ca.sup.2+ ions (hereinafter, referred to as “Ca.sup.2+ALG”). To sufficiently fill the spheres with DOBDC.sup.4− ligands, immersion of the spheres into a 0.1 M DOBDC.sup.4− solution was repeated 3 times.

[0109] A 0.5M Zn(NO.sub.3).sub.2 solution was prepared in a 1:1 mixture of H.sub.2O and ACT. After drying of the spheres for 1 h, the spheres were immersed into the 0.5M Zn(NO.sub.3).sub.2 solution. DOBDC.sup.4− ligands in the Ca.sup.2+ALG were allowed to react with Zn.sup.2+. The reaction was conducted at room temperature for 30 min.

EXPERIMENTAL EXAMPLE

[0110] The following devices were used in each experiment. [0111] UV-visible light absorption spectrum: an Agilent 8453 UV-VIS spectrophotometer was used. [0112] PXRD pattern: a PANalytical diffractometer (Empyrean) with a monochromatic nickel-filtered Cu Kα beam was used. [0113] Optical microscope: an S43T microscope (Bimeince) was used. [0114] Scanning electron microscope (SEM): an FE-SEM (Hitachi S-4800) was used and operated at an acceleration voltage of 3 kV, after samples were coated with Au—Pt alloys with a thickness of 3 nm. [0115] Energy dispersive X-ray spectroscopy (EDS): an XFlash® 5030 Detector (Bruker) equipped on an FE-SEM was used.

[0116] Thermogravimetric analysis (TGA): was performed under N.sub.2 gas at a flow rate of 100 mL/min using a Q500 (TA Instruments).

Experimental Example 1: Microscope Analysis

[0117] The spheres prepared in Example 1 and Comparative Example 1 were individually observed through the optical microscope and the SEM (FIGS. 3 and 4). The changes during the reaction were observed every 5, 10, 20, 30, and 60 min after the reaction, and a region (i) of an outer surface, a region (ii) near a surface, a region (iii) far from the surface, and a core region (iv) were individually observed.

[0118] In the spheres of Comparative Example 1, HKUST-1 crystals were generated only on and near the surface after a reaction time of 1 h, and a structure having a core and a shell enclosing the core, like an egg, was observed (FIG. 3). In the spheres of Example 1, HKUST-1 crystals were generated uniformly from the core region to the surface (FIG. 4). In particular, crystals were generated from a point in time at which 5 min elapsed after the reaction, and accordingly it is confirmed that crystals may be generated within a relatively short period of time and that crystals with a uniform size were generated.

[0119] The membranes of Example 2 and Comparative Example 2 were individually observed with naked eyes and the SEM (FIGS. 5A through 5D and 6A through 6D). All the membranes were prepared as flexible polymer membranes, and a polymer membrane with a thickness of approximately 140 μm was shown. In particular, it is confirmed that HKUST-1 crystals were uniformly generated in all regions of the membrane of Example 2.

[0120] The spheres prepared in Example 3 and Comparative Example 3 were individually observed by the SEM and shown in FIG. 7 (Comparative Example 3: LD-MOF74-ALG, and Example 3: MD-MOF74-ALG). In particular, it is confirmed that MOF74 crystals were generated uniformly from a core region to a surface in the spheres of Example 3 and have a uniform size.

[0121] The spheres prepared in Example 1 were magnified and observed by the SEM to observe HKUST-1 crystals at each region in more detail (FIGS. 8A through 8C). It is confirmed that crystals are distributed uniformly from a core region to a region on a surface and have similar sizes. Also, it is confirmed that HKUST-1 crystals and a polymer matrix are well bonded.

[0122] As described above, it may be found that in the MOF-containing matrix prepared by the method according to the present invention, MOFs have a uniform size and are well bonded to a polymer matrix. Also, it is confirmed that MOF crystals are uniformly dispersed in the matrix.

Experimental Example 2: XRD Analysis

[0123] XRD patterns of the spheres prepared in Example 1 and Comparative Example 1 and the spheres prepared in Preparation Example 1 were compared and shown in FIGS. 9 and 10. Also, for comparison, an XRD pattern of each of a state (Cu.sup.2+ALG) before ligands were added in Comparative Example 1 and a state (Ca.sup.2+ALG) before copper ions were added in Example 1 is shown. Comparing HKUST-1 crystals (HKUST-1 Powder), the matrix of Example 1 showed almost identical patterns, and accordingly it is confirmed that the HKUST-1 crystals were well generated in the matrix prepared by the method according to the present invention. XRD patterns of the membranes prepared in Example 2 and Comparative Example 2 are shown in FIGS. 11 and 12. XRD patterns of the MOF-74(Zn) crystals of Preparation Example 2 and the matrices prepared in Example 3 and Comparative Example 3 are shown in FIG. 13. It is confirmed that crystallinity of MOF crystals generated in the matrices of Examples 2 and 3 are well exhibited.

Experimental Example 3: Ion and Crystal Distribution Analysis for Different Reaction Time of Example 1

[0124] To confirm an ion exchange process of a matrix in which metal ions are dispersed,

[0125] SEM measurements and EDS analysis of 5, 10, 20, 30, and 60 min after a reaction of adding copper ions in Example 1 were performed. It is confirmed that the amount of Ca.sup.2+ ions decreased and the amount of Cu.sup.2+ increased as the reaction time passed so that ions were well exchanged, and thus it may be found that the HKUST-1 crystals are uniformly generated.

Experimental Example 4: Analysis of Adsorption Characteristics

[0126] To confirm a size of an open coordination site and material adsorption characteristics of metal-organic frameworks-containing matrix, adsorption capacities of the matrices of Example 1 and Comparative Example 1 with respect to methylene blue (MB) and rhodamine 6G (R6G) were confirmed.

[0127] First, 1.5 mL of 6.0 μM MB/MeOH was placed in a silicone-capped quartz cuvette, and a UV-visible light absorption spectrum was measured.

[0128] 0.25 g of the spheres LD-HK-ALG of Comparative Example 1, the spheres MD-HK-ALG of Example 1, the spheres Cu.sup.2+ALG in which ligands were not added in Comparative Example 1, and the spheres Ca.sup.2+ALG in which copper ions were not added in Example 1 were respectively added in the MB solution, followed by immediately measuring of absorption spectra every 5 min, which continued for 6 h.

[0129] 1.5 mL of 6.0 μM R6G solution was added, and the same experiment as that of MB was repeated.

[0130] Absorption spectra of MB and rhodamine 6G are shown in FIGS. 15A through 15D, and absorption coefficients thereof were obtained as 74,760 and 95,270 M.sup.−1 cm.sup.−1 at 652 and 528 nm, respectively.

[0131] Based on this, an absorption spectrum of each of the spheres was analyzed, and it is confirmed that almost no adsorption occurred in the spheres Cu.sup.2+ALG in which ligands were not added in Comparative Example 1, and the spheres Ca.sup.2+ALG in which copper ions were not added in Example 1 (FIGS. 16A through 16F). In other words, it may be found that absorption of MB and rhodamine 6G hardly occurs in a matrix before MOFs are generated.

[0132] Referring to absorption spectrum results of the spheres LD-HK-ALG of Comparative Example 1 and the spheres MD-HK-ALG of Example 1, both the spheres LD-HK-ALG and MD-HK-ALG adsorbed MB but did not adsorb rhodamine 6G (FIGS. 17A through 17I). This indicates that HKUST-1 and windows thereof are uniformly generated in the matrices prepared in Example 1 and Comparative Example 1. Specifically, referring to a molecular size of each of MB and rhodamine 6G and a size of the window in the HKUST-1 as shown in FIGS. 18A through 18C, the window in the HKUST-1 has a size of 8.5 Å, so as to adsorb MB (7.0 Å) that is less in size than the window, but it is difficult to adsorb rhodamine 6G (13.0 Å) that is greater in size than the window. Thus, the HKUST-1 may perform selective adsorption based on a molecular size through the window thereof. However, when the HKUST-1 does not uniformly grow, the size of the window may not be uniform, thereby making it difficult to perform the above-described selective adsorption.

[0133] It may be found that the matrix of Example 1 prepared according to the present invention was grown as a structure having a uniform window size, and accordingly selective adsorption based on a molecular size is possible.

[0134] XRD patterns before and after adsorption of the spheres of Example 1 were observed (FIG. 19). It may be found that even after the adsorption, HKUST-1 crystals remain unchanged.

Experimental Example 5: TGA

[0135] A TGA of each of the spheres of Example 1 and Comparative Example 1 was performed (FIGS. 20A and 20B). Measurements were performed at 30 min after each reaction, and a decomposition temperature of the spheres of Example 1 was in a range of 110 to 175° C., a range of 175 to 285° C., and a range of 285 to 380° C. A first temperature range is caused by evaporation of a solvent, a second temperature range is caused by decomposition of alginate, and a third temperature range is caused by decomposition of HKUST-1 crystals. Based on the above ranges of the decomposition temperature, an amount of HKUST-1 crystals generated may be inferred.

[0136] It would be appreciated by those having ordinary knowledge in the art to which the present disclosure pertains that various modifications and variations can be made from the foregoing descriptions without changing technical ideas or essential features of the present disclosure. Therefore, the aforementioned example embodiments are construed as not being restrictive but being illustrative. The scope of the present disclosure is defined by the appended claims, and all variations and modifications made from the meanings and scope of the claims and their equivalents are construed as being included in the scope of the present disclosure.