KR20230030192A - Porous chelate beads having aminated polyacronitrile structure and its preparation method - Google Patents

Abstract

The present invention relates to porous chelate beads, and a preparation method thereof, and specifically, provides porous chelate beads exhibiting high porosity and high adsorption capacity as well as amphoteric adsorption performance of cations and anions, and a preparation method thereof.

Description

Porous chelate beads having aminated polyacrylonitrile structure and its preparation method {Porous chelate beads having aminated polyacronitrile structure and its preparation method}

The present invention relates to an adsorption material for removing pollutants in water and air, and to a porous chelate bead having an aminated polyacrylonitrile structure for removing harmful substances such as heavy metals, harmful gases, arsenic compounds and phosphorus compounds, and a method for manufacturing the same it's about More specifically, it relates to chelate beads having a functional porous structure and their preparation through the steps of synthesizing polyacrylonitrile beads having a porous structure and introducing an amine-based compound to the surface of the porous structure.

As the industry develops, the discharge of water pollutants such as various industrial wastewater, livestock wastewater, and domestic wastewater is continuously increasing. need. To this end, related studies such as chemical precipitation, electrolysis, membrane, bio-adsorption, and physico-chemical adsorption are being actively conducted. Among them, the chemical adsorption method is proposed as the most efficient method due to advantages such as low cost, high removal efficiency at low concentration, and low pH sensitivity.

Currently, there are polystyrene-based polymer resins with various chemical adsorption functional groups as commercial adsorption bead materials (Korean Patent Nos. 10-1321035, 10-0621945 and 10-2029403), but most of them have a low porosity structure and low adsorption. However, the synthetic manufacturing process has complex disadvantages. Therefore, in order to solve these problems, an adsorption material technology capable of efficiently collecting pollutants is required in consideration of high porosity, high adsorption performance, and simplicity of the manufacturing process.

Among the technologies that can realize a conventional polymeric porous structure, gel-type resin is prepared by direct suspension polymerization of a crosslinking agent having one or two vinyl groups without a solvent, and fine pores, which are the distances between polymer chains in a solid state when dried, can hold However, when the amount of the crosslinking agent is less than 1%, the polymer resin has a high degree of swelling but very low mechanical strength and is easily damaged, whereas a commercially available crosslinked gel-type resin is mechanically very stable but has a low degree of swelling and the reactant penetrates into the gel. Therefore, it is difficult to access the activator. That is, since the reaction rate is slow or incomplete inside the resin having a high degree of crosslinking, it is not suitable for use as an adsorbent.

In contrast, porous resins have a similar manufacturing method to gel-type resins, but a solvent that serves to form pores during polymerization must be added. When the solvent dissolves both the monomer and the polymer, a completely swollen network is formed and can have many pores. When the solvent is removed from the polymerized porous resin, the polymer matrix partially collapses, but many pores are formed due to the dissolved and swollen network during polymerization. can At this time, in order to have appropriate mechanical strength, a crosslinking degree of 20% or more must be added, and since this is a part that cannot be used as an adsorbent, it is directly related to the problem of deterioration of adsorbent performance.

Compounds containing amine functional groups are well-known compounds capable of treating both cations and anions. However, when the liquid amine compound is directly applied as an environmental treatment material, problems such as harmfulness to the human body, corrosion, and adverse effects on the ecosystem occur, so a method of polymerizing or fixing to a specific support is used, but a polymer monomer containing an amine functional group had a problem in that it was difficult to polymerize into a polymer because of the ability to absorb the radicals of the amine functional group well.

(Patent Document 1) KR 100412203 (Patent Document 2) KR 101816008 (Patent Document 3) KR 102000389 (Patent Document 4) KR 101776370 (Patent Document 5) KR 102025087 (Patent Document 6) KR 101321035 (Patent Document 7) KR 100621945 (Patent Document 8) KR 102029403

In order to solve the above problems, the present inventors confirmed that a structure having a porous structure was created at a specific polymer concentration while studying a structure capable of maximizing an adsorption area advantageous as an adsorbent, and through surface modification of the adsorbent. completed the present invention.

In the present invention, heavy metal cations and anions such as arsenic and phosphorus present in water and air are used to overcome the disadvantages of existing widely used styrenic ion exchange resins such as low porosity, low adsorption performance, and complexity of manufacturing process. An object of the present invention is to provide a porous chelate bead having an aminated polyacrylonitrile structure and a manufacturing method thereof as an adsorbent material capable of efficiently removing the same.

In addition, the present invention provides a method for manufacturing millimeter-scale polyacrylonitrile (PAN) beads having a porous structure, and an amine functional group is added to introduce functionality capable of removing cationic / anionic contaminants from the porous beads. It is intended to provide a method of immobilizing the porous bead.

In order to achieve the above object, the present invention provides a method for producing polyacrylonitrile beads having a porous structure.

In addition, polyacrylonitrile beads prepared by the above method are provided.

The method for producing the porous structure polyacrylonitrile beads,

(A) dissolving polyacrylonitrile resin or fiber in an organic solvent;

(B) injecting droplets of the solution in which the polyacrylonitrile resin or fibers in (A) is dissolved into a mixture of water and ethanol using a nozzle;

(C) reacting the porous polyacrylonitrile beads produced in (B) with an amine compound to modify the surface;

Step (A) is specifically, preparing millimeter-sized polyacrylonitrile beads having a porous structure through a solvent exchange method by dissolving polyacrylonitrile resin or fiber in an organic solvent, and adding an amine compound to the porous structure Incorporating it into the surface.

Conditions for preparing the porous polyacrylonitrile chelate beads are not limited, but are preferably 1 to 30 parts by weight, preferably 5 to 25 parts by weight, more preferably 10 parts by weight, based on 100 parts by weight of the organic solvent used. to 20 parts by weight may be added. If the resin or fiber exceeds the weight part, beads may not be formed well.

The organic solvent may be selected from the group consisting of a solution capable of dissolving a polyacrylonitrile polymer. For example, diethyl ether, diisopropyl ether, dimethylsulfoxide (DMSO), dimethylformamide (DMF), acetonitrile, N-methyl-2 -Pyrrolidone (N-methyl-2-pyrrolydone, NMP), tetrahydrofuran (THF), etc. may be used, preferably DMF, but is not limited thereto.

In step (B), the solution in which the polyacrylonitrile resin or fibers are dissolved in step (A) is introduced into the water/ethanol solution through a nozzle .

The water/ethanol ratio is not limited, but may preferably be included in a weight ratio of 1:1. This is because the specific gravity of an organic solvent, for example, DMF, is 0.95 g/ml, water is 1 g/ml, and ethanol is 0.79 g/ml, but the specific gravity of water without ethanol is higher than that of DMF. This is because it floats on water, making it impossible to prepare a porous spherical structure. Therefore, it is preferable that the water / ethanol is included in the above ratio, wherein the specific gravity is 0.8 to 1.0 g / ml, preferably 0.9 g / ml, and the DMF in which the fibers are dissolved sinks in water to form a spherical structure. there is.

In the present invention, the method of introducing the droplets of the polyacrylonitrile solution into the water/ethanol solution may be any method capable of forming droplets by passing the polymer solution through the nozzle at a flow rate of 0.1 to 20 ml per minute.

The diameter of the nozzle for injecting the polyacrylonitrile solution according to an embodiment of the present invention may be adjusted to 0.001 to 10 mm depending on the viscosity of the solution and the size of the desired structure.

The mixing ratio of the water/ethanol mixed solution into which the droplets of the polyacrylonitrile solution are input may be determined in a range equal to or lower than the density of the polyacrylonitrile solution, and among substances other than this combination, the organic solvent used Depending on the type, it may be mixed with an organic solvent, and may be any one of solvents having the same density or a lower range, but is not limited thereto.

According to the molecular weight of the polyacrylonitrile polymer introduced in the present invention, the viscosity within a range capable of flowing in an organic solvent and the weight ratio relative to the organic solvent may be changed within a range capable of maintaining a structure after solvent exchange.

In the present invention, the water / ethanol mixed solution can be mixed with each other at the same time as having the same or lower density than the polyacrylonitrile solution, and when the two used polyacrylonitrile solutions and the solution come into contact, they are dissolved by a solvent exchange mechanism It may be at least one selected from the group consisting of a solution capable of solidifying a polymer having a polymer.

In step (C), the amine compound may be diethylenetriamine, which is an alkylamine compound having a linear structure that can be densely bound to the surface of the prepared porous polyacrylonitrile beads. This can increase adsorption efficiency because a small number of amine functional groups are used to adsorb ionic substances as a forehand structure. However, it may be a primary or more amine compound having an alkyl group among materials capable of acting as a ligand by binding to the nitrile functional group. The amine compound may have a cyclic structure. For example, ethylenediamine (EDA), diethylenetriamine (DETA), tris(2-aminoethyl)amine, propane-1,3-diamine -diamine), methane triamine, 3-(2-aminoethyl)propane-1,5-diamine (3-(2-aminoethyl)pentane-1,5-diamine), melamine, It may include one or more selected from the group consisting of diaminofurazan, diaminopyridine, polyethyleneimine, and diaminopyrimidine, but is not limited thereto.

At this time, the ratio of the polyacrylonitrile beads may be 1 to 50 parts by weight, preferably 5 to 30 parts by weight, more preferably 10 to 20 parts by weight, based on 100 parts by weight of the amine compound. When the ratio of polyacrylonitrile beads is included in less than the above parts by weight, beads may not be formed, and when included in excess of the above range, bead formation may be limited due to high viscosity.

Although not limited to the above modification, it is preferably put into a reactor containing a diethylenetriamine (DETA) solution and reacted. At this time, the reaction temperature is 50 to 10 °C, preferably 80 to 120 °C, more preferably 100 °C for 30 minutes to 3 hours, preferably 1 to 2 hours. Outside the above temperature range and time, the immobilization rate of the amine complex slows down, and thus the reaction time may increase.

When a catalyst is used to modify the surface of beads, types of catalysts include acetic acid, hydrochloric acid, boron trifluoride dihydrate (BF ₃ 2H ₂ O), and the like. It may be selected from metal-based Lewis acid-based catalysts of non-metal-based Lewis acids or metal chlorides such as aluminum chloride hexahydrate, and the amount of catalyst added is 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the polyacrylonitrile beads added. Part by weight may be added. When the catalyst is included in an amount less than the above parts by weight, the catalytic reaction may be delayed, and when the catalyst is included in an amount exceeding the above range, the catalytic reaction may be excessive.

The term "bead" in the present specification refers to grains of a size capable of maximizing an adsorption area. The average particle size may be several nm to several cm, preferably 100 nm to 1 cm, and preferably 10 mm to 70 mm as an adsorbent, but is not limited thereto.

The present invention provides a technique for preparing a spherical structure with a size of several millimeters of a porous structure, which is advantageous as an adsorbent, and introducing an amine functional group into the porous structure.

An amine functional group is known as a functional group capable of adsorbing both cations and anions in water, but monomers containing amine functional groups have the property of neutralizing radicals that are inevitably generated during the polymerization of amine functional groups, making it a millimeter-sized polymer. Synthesis is not suitable. For this reason, a polyacrylonitrile porous structure having a nitrile functional group that can be easily post-treated with an amine functional group is prepared, and then the porous structure is aminated and modified with diethylenetriamine to prepare a porous structure chelate bead.

The porosity of the porous beads prepared according to the present invention may be 50 to 90.

In addition, the moisture content of the porous beads prepared according to the present invention may be 400 to 1000.

In one embodiment of the present invention, the diameter of the prepared porous structure may be 0.01 to 10 mm.

The bead having a functional porous structure according to the present invention is not limited to the method described above, and includes a range of structures capable of controlling the shape of the multi-stage porous structure in a desired shape using a mold.

In one embodiment of the present invention, the height of the nozzle into which the first solution is injected may be adjusted from 0.1 to 100 cm depending on the viscosity of the first solution from the surface of the second solution contained in the reaction tank.

Referring to Figure 1, the manufacturing apparatus of the porous structure used in one embodiment of the present invention is provided with a reaction tank. The reactor is filled with a miscible solution and having a lower density than the solution so that the polyacrylonitrile droplets can settle when introduced. When the polyacrylonitrile solution is introduced into the solution below, the polymer is solidified from the interface. Leave for at least 30 minutes so that the solvent can be sufficiently exchanged from the surface of the prepared particles to the internal structure.

Referring to Figures 2 and 3, it can be seen that the internal porous structure of the polyacrylonitrile beads is maintained even after surface amine modification.

Referring to FIG. 4 , it can be confirmed that heavy metal ions are easily penetrated into the prepared functional porous beads and adsorbed on the surface of the adsorbent through a surface precipitation mechanism.

Referring to FIG. 5, beads were not easily formed under the condition that the content of PAN in the solvent was 5% or less and 20% or more. Therefore, in consideration of adsorption performance and bead formation conditions, the content of polyacrylonitrile polymer (PAN) in the solvent may be set to a weight ratio of 10 to 15 in consideration of adsorption performance.

Referring to FIG. 7, the adsorption performance of commercially available adsorbents (HCR-S, DOW; MION AK-22, Imatek & K, LTD; MION K-5, Imatek & K, LTD) and the beads according to the present invention As a result of the comparison, it can be confirmed that the adsorption performance is more than three times higher.

Referring to FIG. 8 , it can be confirmed the adsorption performance of the beads according to the present invention for cations and anions. It can be confirmed that both cations and anions are easily adsorbed to the functional porous chelate beads.

The present invention can synthesize polymer beads having a porous structure with a size of several millimeters having an amine functional group, and the amine functional group can have both cation and anion properties, which can remove both cation and anion, which are pollutants in water quality and air. It is well known as a chemical functional group. In addition, since contaminants can easily permeate into the adsorption material using the high pore structure, it shows excellent adsorption performance. Therefore, the millimeter-scale porous polyacrylonitrile beads having the porous structure can be widely used, such as being applied to atmospheric and harmful gas purification devices, various rare metal and heavy metal separation and recovery devices, and the like.

In addition, the beads having an aminated polyacrylonitrile structure prepared according to the present invention are economical because they can be manufactured in a simple two-step process, and have a porous structure with a size of several millimeters that can maximize adsorption functionality, so they are conventional adsorbents. It is possible to supplement problems that occur during actual use of them. In addition, it can be used in various fields such as catalysts, capacitors, sensors, adsorbents, absorbents, and oil absorbers where the surface functionality of particles is important.

1 is a schematic diagram and chemical formula for explaining a method for manufacturing APAN beads having a porous structure according to an embodiment of the present invention.
Figure 2 is an FT-IR graph of the porous PAN beads and the aminated PAN beads of the present invention, showing the difference in chemical functional groups. The nitrile (-C≡N) group (2240 cm ^-1 ), the main functional group of PAN, disappears upon surface amine modification, and the peak corresponding to the introduced diethylenetriamine functional group (3346, 1590, 1573, 1485 cm ^{- 1} ), it is a graph confirming that the surface modification has been successfully performed.
3 is a SEM image of poly(amidino diethylene diamine) (PADD) surface-modified with an amine compound, showing an internal porous structure.
4 shows (a) a real picture of the prepared aminated porous PAN beads, (b) a real picture of the beads after Cu ²⁺ adsorption, (c) a SEM image of (b) a sample, and (d) a further enlarged SEM represents an image. Comparing pictures (a) and (b), copper ions show that it is easy to penetrate into the inside of the bead, and (c) and (d) images show that metal ions are precipitated by amine functional groups inside the bead in crystal form. It shows adsorption.
5 is a graph showing cation/anion adsorption performance and cation exchange performance of beads prepared according to the content of PAN in a solvent (Dimethylformamide, DMF).
6 is a chart showing information on the moisture content, porosity, and average pore diameter of the PAN beads prepared in FIG. 5;
7 is a graph showing the adsorption performance of the patented development product, and shows excellent adsorption performance compared to conventional ion exchange adsorption beads and fibers that are commercially used.
8 is a chart showing the adsorption performance of cations (Fe ²⁺ , Cu ²⁺ , Pb ²⁺ , Zn ²⁺ ) and anions (AsO ₄ ^- , PO ₄ ^3- ) of beads according to the present invention.

Hereinafter, the present invention will be described in detail by examples and experimental examples.

However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the contents of the present invention are not limited to the following Examples and Experimental Examples.

Example 1: Manufacturing a millimeter-sized porous structure by solvent exchange after dissolving polyacrylonitrile (PAN) polymer in dimethylformamide (DMF)

15 g of PAN resin was dissolved in 100 g of solvent DMF at room temperature for 3 hours. A droplet of the prepared PAN solution is injected into a water/ethanol solution having a weight ratio of 1:1 through a nozzle. At this time, the injection rate is in the range of 0.1 to 20 mL per minute depending on the size of the desired bead. After solvent exchange at room temperature for 1 hour, the resulting porous PAN beads are washed with water and dried.

Example 2: Introduction of diethylenetriamine to the surface of polyacrylonitrile beads

15 g of the porous PAN beads synthesized in Example 1 were injected into 100 g of diethylenetriamine solution. After reacting at a synthesis temperature of 100 ° C. for 2 hours, the beads are washed with water and dried.

Example 3: Method for manufacturing polyacrylonitrile beads having a porous structure using a dimethyl sulfoxide solvent.

It was prepared by the same procedure as in Example 1 except that the solvent was dimethyl sulfoxide instead of DMF.

Example 4: Introduction of diethylenetriamine onto the surface of polyacrylonitrile beads using metallic and non-metallic Lewis catalysts

It is prepared in the same manner as in Example 2, but under the conditions of a reaction temperature of 100 ° C and a reaction time of 1 hour under boron triple chloride dihydrate (BF ₃ 2H ₂ O) at a weight ratio of 1 to the introduced PAN beads. Wash the beads with water and dry did

<Experimental Example 1> Evaluation of bead characteristics according to the solvent

The characteristics of the beads prepared according to the solvent were evaluated using the above Examples 1 and 3, and evaluation was conducted on whether the porous structure of the beads was formed effectively (FIG. 4) by analyzing the shape of the beads using an electron microscope. did As a result of the experiment, it was confirmed that there was no structural change according to the type of solvent.

<Experimental Example 2> Evaluation of bead characteristics according to the catalyst

In the case of using Examples 4 and 2, whether the immobilization of the amine functional group occurs according to whether or not the catalyst was added and the type of the catalyst was evaluated using FT-IR equipment and shown in FIG. 2. As a result of the experiment, the peak of the nitrile group (2245 cm ^-1 ), which is the main reactive group of the PAN material before the reaction, decreases and the amine group at 1590 cm ^-1 It was confirmed that the reaction proceeded successfully through the occurrence of a peak for .

<Experimental Example 3> Evaluation of adsorption capacity of beads according to polyacrylonitrile content

When preparing beads according to the present invention, the cation / anion adsorption performance and cation exchange performance (adsorption capacity) of the prepared beads were evaluated according to the amount of PAN introduced in the solvent (Dimethylformamide, DMF). It was prepared in the same manner as in Example 1, but the content of PAN was added at 5, 7, 10, 15, and 20% by weight, respectively.

As a result of the experiment, it was confirmed that the total adsorption amount was measured when the amount of PAN introduced was 7, 10, and 15 wt%, and in particular, the total adsorption amount including copper and phosphorus adsorption was excellent at 10 and 15 wt%.

<Experimental Example 4> Evaluation of moisture content and porosity of beads according to the present invention

The pore size and average pore diameter of the beads were measured with a Porosimeter (mercury adsorption method), and the results are shown in FIG. 6. Referring to FIG. 6, the characteristics of the PAN beads (Example 1) produced in FIG. 5 before and after amination (Example 2) can be confirmed, and the increased moisture content and the porosity and average pore diameter even after amination It can be seen that there is no significant change.

<Experimental Example 5> Evaluation of adsorption capacity of beads according to the present invention

The total adsorption equivalent was calculated by adding the aminated PAN beads generated in Example 2 to a 1 M HCl solution at a concentration of 0.1 g/L, and titrating the concentration of H ⁺ ions adsorbed after 24 hours using a 1 M NaOH solution was measured. In addition, a solution of 3000 mg/L for cations/anions such as iron, copper, phosphorus, arsenic, lead, and zinc was prepared, and the aminated PAN beads generated in Example 2 were added at a concentration of 0.1 g/L and allowed to stand for 24 hours. After being allowed to stand for a while, the amount of adsorption was evaluated using ICP-OES equipment and shown in FIG.

As a result of the experiment, it was found that the beads according to the present invention had excellent adsorption capacity for iron and copper, and also excellent adsorption capacity for lead, zinc, arsenic and phosphorus.

Claims (10)

(A) dissolving polyacrylonitrile resin or fiber in an organic solvent;
(B) injecting droplets of the solution in which the polyacrylonitrile resin or fibers in (A) is dissolved into a mixture of water and ethanol using a nozzle;
(C) modifying the surface of the porous polyacrylonitrile beads produced in (B) by reacting with an amine compound. The method of claim 1, wherein in step (A), the polyacrylonitrile resin or fiber is dissolved in an amount of 1 to 30 parts by weight based on 100 parts by weight of the organic solvent. The method of claim 1, wherein the organic solvent is diethyl ether, diisopropyl ether, dimethylsulfoxide (DMSO), dimethylformamide (DMF), acetonitrile , N-methyl-2-pyrrolidone (N-methyl-2-pyrrolydone, NMP), tetrahydrofuran (tetrahydrofuran, THF) method for producing a porous bead, characterized in that selected from. The method of claim 1, wherein in step (B), water and ethanol are mixed in a weight ratio of 1:1. The method of claim 1, wherein the droplet injection rate in step (B) is a flow rate of 0.1 to 20 ml per minute. The method of claim 1, wherein the amine compound in step (C) is ethylenediamine (EDA), diethylenetriamine (DETA), tris (2-aminoethyl)amine (tris (2-aminoethyl)amine) , propane-1,3-diamine, methane triamine, 3-(2-aminoethyl)propane-1,5-diamine pentane-1,5-diamine), melamine, diaminofurazan, diaminopyridine, polyethylene imine and diaminopyrimidine, characterized in that selected from A method for producing porous beads. The method of claim 1, wherein in step (C), the porous polyacrylonitrile beads are reacted in an amount of 5 to 30 parts by weight based on 100 parts by weight of the amine compound. The method of claim 1, wherein step (C) is performed at 80 to 120° C. for 30 minutes to 3 hours. The method of claim 1, wherein the catalyst is additionally reacted in step (C), and the catalyst is reacted in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the polyacrylonitrile beads. The method of claim 9, wherein the catalyst is acetic acid (acetic acid), hydrochloric acid (hydrochloric acid), boron trifluoride dihydrate (BF ₃ 2H ₂ O), aluminum chloride hexahydrate characterized in that any one or more of the porous beads manufacturing method.

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