KR100768406B1 - New innovative functional composites comprising mesoporous carbon-based material and functional polymer - Google Patents

Abstract

A functional composite useful as an agent for improving the quality of water is provided to improve stability in an aqueous solution and metal removing property, to increase the content of a functional polymer and to allow it to be separated from an aqueous solution easily. A functional composite comprises a mesoporous carbon-based material matrix having an average pore size of 2-30 nm; and a complex forming polymer which is adsorbed to the matrix strongly to form a complex with a metal ion. Preferably the mesoporous carbon-based material is at least one selected from the group consisting of a carbon having a regular pore structure, a carbon having an irregular pore structure, a carbon having a hollow core and a mesoporous shell, a carbon having a non-hollow core and a mesoporous shell, their derivative and their mixture.

Description

New Innovative Functional Composites Comprising Mesoporous Carbon-based Material and Functional Polymer

1 is a graph showing the adsorption isotherm of polyethyleneimine on mesoporous carbon and activated carbon; And

2 is a graph showing UO ₂ ^{2 +} adsorption isotherm of F400 / CM-PEI complex and F400.

M. Chanda, Reactive Polymers , vol. 25, pp. 25, 1995.

2.D. Leroy, J. Applied Polymer Science , vol. 88, pp. 352, 2003.

3.A. Denizli, Reactive and Functional Polymers , vol. 55, pp. 121, 2003.

4.J. Wang, J. Colloid and Interface Science , vol. 216, 436, 1999.

M. Ghoul, Water Research vol. 37, pp. 729, 2003.

The present invention relates to a novel concept of functional composites composed of mesoporous carbon-based materials and functional polymers. In particular, due to the strong bonding of the mother and functional polymers, a high stability is achieved in an aqueous solution and a mother having a large specific surface area that is substantially accessible to the polymer and a functional polymer that forms a strong complex with various metal species, It is a new concept of functional composites composed of mesoporous carbon-based materials and functional polymers that not only have the ability to remove metals but also can be easily separated from aqueous solutions through simple separation processes.

Conventionally, in order to separate and remove radioactive materials containing heavy metals or actin elements in an aqueous solution, ceramic materials such as silica or zirconia or organic materials such as organic polymers or organic resins are matrixed. Various complexes have been developed that are used as a functional polymer on top of it.

Chanda et al. Produced a composite coated with polyethyleneimine on silica and showed improved performance at the time of uranium separation [1]. Leroy et al. Composited a polyethyleneimine derivative with polypyrrole. Was prepared and applied to separate uranium ions [2].

Denizil et al. Prepared a composite material by modifying a poly (2-hyrdoxyethylmethacrylate) bead surface with polyethyleneimine to remove mercury from an aqueous solution [3. ].

Wang et al prepared composites using zirconia as a mother and polyethyleneimine as a functional polymer [4], and Goul et al. Prepared composites by modifying the surface of crosslinked silica with polyethyleneimine. It was applied to the removal of heavy metals such as lead (Pb), zinc (Zn), cadmium (Cd) and nickel (Ni) [5].

However, the conventional inventions based on such inorganic materials and resins have some problems as follows.

First, the bond between the parent and the functional polymer is weak, so that the functional polymer is dissolved in the aqueous solution and the stability of the composite is inferior. In this case, it is difficult to separate the dissolved functional polymer by a simple filtration process, and as a result, it is impossible to completely remove the heavy metal or radioactive material in the aqueous solution.

Second, the conventional ceramic or organic resin matrix has a low specific surface area and a weak bond with the functional polymer, making it difficult to increase the functional polymer content in the composite. Therefore, the amount of removal of metal per unit weight of the composite has a disadvantage.

In addition, US Patent Nos. 2003/0118823 and 2005/0035062 describe various organic pollutants, including benzene, chloroform and toluene, and metals including cadmium (Cd), radon (Rn) and selenium (Se). Activated carbon based composite technology is disclosed, in which polyethylene is introduced to the surface of activated carbon through an emulsion spray technique to produce a composite.

Recently, Taek-Sung and others prepared ACF-PP-g-AAc copolymers by polymerizing acrylic acid (AAc) on the activated carbon fiber (ACF) and polypropylene (PP) hybrid nonwoven fabrics by radiation polymerization method. Therefore, the adsorption characteristics of various heavy metals such as manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), and the like were evaluated.

Japanese Patent No. 58150434 discloses a technique for preparing an adsorbent for removing heavy metals by treating activated charcoal with polyethyleneimine and carbon disulfide (CS ₂ ). In addition, Japanese Patent No. 58223439 discloses a technique for preparing a heavy metal adsorbent in which polyethyleneimine having a molecular weight of 600 to 6000 is coated on activated carbon and then an epoxy crosslinker and carbon disulfide (CS ₂ ) are sequentially reacted.

However, the conventional inventions based on the existing carbon-based materials have some problems as follows.

First, the existing carbon-based material has a disadvantage that the specific specific surface area is reduced and the polymer content is not greatly increased because the polymer does not reach the carbon inside because the pore size is small.

Second, conventional functional polymers have a low bond strength when reacting complexes with metal ions, resulting in a substantially low metal removal relative to the weight of the adsorbent.

Therefore, the present invention is applicable to various physical and chemical environments by increasing the stability of the complex in aqueous solution to solve the problems of the conventional metal removal complex and a novel mesoporous carbon-based material and functional polymers showing higher metal ion adsorption characteristics The purpose is to provide a conceptual functional complex.

In order to achieve the above object, the present invention provides a functional composite comprising a matrix of mesoporous carbon-based material, and at least one functional polymer strongly adsorbed to the matrix.

 In addition, the present invention provides a functional complex comprising a carboxymethylated polyethyleneimine strongly adsorbed to the mother and mother of the carbon-based material.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention includes a functional complex for separating heavy metals and radioactive materials in an aqueous solution.

Specifically, the present invention includes a new concept functional complex composed of a matrix which is insoluble in water and a functional polymer that is strongly adsorbed to the matrix to form a complex with metal ions. It includes a new concept of functional composites characterized by the use of carbon-based materials in form or structure.

In the mesoporous carbon-based material having various structures according to the present invention, the mesoporous carbon-based material has excellent stability in aqueous solution due to strong bonding with a functional polymer, and has a large specific surface area substantially accessible to the polymer. In order to significantly increase the loading of the functional polymer by using the matrix, carbon having a regular pore structure and carbon having an irregular pore structure, carbon having a hollow and mesoporous portion in the shell portion, a hollow and shell It is preferable that at least one selected from the group consisting of carbons having mesopores in the moiety), derivatives thereof, and mixtures thereof.

The mesoporous carbon-based material has a pore size in the range of 2 nm to 50 nm because the mesoporous carbon-based material should be able to adsorb with more polymers by providing a larger specific surface area in order to separate a large amount of metal in an aqueous solution. If the pore size is smaller than 2 nm, the polymer does not reach the inside of the carbon. If the pore size is larger than 50 nm, the specific surface area becomes smaller, thereby reducing the effect of increasing the polymer content.

In the functional polymer according to the present invention, the functional polymer material exhibits a high adsorption amount by using a functional polymer that forms a strong complex with various metal species, an imine polymer, an alcohol polymer, an acrylic polymer, a phenolic polymer, and a vinyl. It is preferable that at least 1 sort (s) is chosen from a type | system | group polymer, a nitrile type polymer, mixtures thereof, derivatives thereof, etc.

Polyethyleneimine, carboxymethylated polyethyleneimine, polyurethane, polyacrylic acid, poly (acrylic acid), polyvinyl alcohol (poly (vinyl alcohol)), polyiminoacetic acid (poly (iminoacetic acid)), mixtures thereof and derivatives thereof may be selected, but not limited thereto.

The composite may further include one or more additives that act as binders to enhance the binding of the parent and the functional polymer.

The additive is polyvinyl pyrrolidone, polyvinylidene fluoride, polyhexafluoropropylene, polyethyl acrylate, polytetrafluoroethylene, At least one may be selected from the group consisting of polyvinyl chloride, polyacrylonitrile, mixtures thereof and derivatives thereof.

The present invention also includes a functional complex comprising a matrix of carbonaceous material and a carboxymethylated polyethyleneimine strongly adsorbed to the matrix.

The carbonaceous material is selected from the group consisting of graphite, carbon fiber, carbon black, carbon nanotube, activated carbon, mixtures thereof, and derivatives thereof. It is preferable that 1 or more types are selected.

The complex should have an adsorbed form with a large amount of polymer in order to separate higher amounts of metal in aqueous solution. Therefore, the molecular weight of the carboxymethylated polyethyleneimine (CM-PEI) used as the functional polymer is preferably 1,000 to 1,000,000, more preferably 10,000 to 500,000.

The complex may further include one or more additives that act as binders to increase the binding force between the parent and the carboxymethylated polyethyleneimine.

The additives include polyvinylpyrrolidone, polyvinylidene fluoride, polyhexafluoropropylene, polyethyl acrylate, polytetrafluoroethylene , Polyvinyl chloride, polyacrylonitrile, polybutadiene, polyisoprene, polyacrylic acid, polyacrylic acid, mixtures thereof and derivatives thereof Can be selected.

Hereinafter will be described in detail the manufacturing process of the composite of the new concept according to the present invention.

The functional polymer is first dissolved in water and then the pH is adjusted. The mixed solution is reacted with a magnetic bar for 2 days while slowly adding carbon to the polymer solution at a specific pH. After the reaction is over, the mixed solution is filtered and washed with excess water to remove the weakly bound polymer from the product complex. The amount of unreacted polymer is measured by a total organic carbon (TOC) analyzer to determine the polymer content in the composite.

By adding various dispersants to improve the dispersion of carbon in the preparation of the composite of the new concept, it is possible to provide a new concept of polymer having a relatively even distribution of polymer and a high polymer content.

Hereinafter will be described in detail the manufacturing process of the composite of a new concept according to an embodiment of the present invention. The examples are only presented to aid the understanding of the present invention, and the present invention is not limited to the following examples.

Example 1 Preparation of Functional Composite Using Mesoporous Carbon

A mesoporous carbon having an average pore size of 4 nm was slowly added at pH 5 to various aqueous solutions of polyethyleneimine (PEI) at various initial concentrations to prepare a complex while stirring for 48 hours. The pH of the mixed solution was adjusted with high purity hydrochloric acid and the ionic strength was adjusted to 0.1M NaNO ₃ . After the reaction had reached equilibrium, the amount of PEI remaining in the solution was measured by total organic carbon analyzer. The amount of PEI in the complex was determined by subtracting the amount remaining from the initial dose.

1 shows the PEI adsorption isotherm that occurs at the mesoporous carbon surface.

Example 2 Preparation of Functional Composite Using Activated Carbon and Copper Adsorption Experiment

Activated carbon (F400, Calgon Carbon Corporation, USA) was slowly added to an aqueous solution of carboxymethylated polyethyleneimine (CM-PEI) at various initial concentrations at pH 5 to prepare a complex while stirring for 48 hours. Was adjusted with high purity hydrochloric acid and the ionic strength was adjusted to 0.1 M NaNO _3. After the reaction had reached equilibrium, the amount of CM-PEI remaining in the solution was measured by total organic carbon analyzer. The amount of CM-PEI in the composite can be determined by determining the amount of CM-PEI in the composite. The amount of copper retained in the solution was filtered after the adsorption reaction reached equilibrium (inductively c). The amount of copper adsorbed was determined by quantification by oupled plasma spectroscopy.

Table 1 summarizes the experimental results of the copper maximum adsorption amount of the composite having a polymer content of 10 wt% and 20 wt% according to Example 2.

Example 3 Uranium Adsorption Experiment

The uranium adsorption characteristics were investigated at various uranium concentrations using a composite having a polymer content of 20 wt% prepared as in Example 2. The uranium solution of various concentrations was prepared by dissolving UO ₂ (NO ₃ ) ₂ (MERCK) in water, and the adsorption experiment was performed at pH 3.5 and the ionic strength was adjusted to 0.1 M NaNO ₃ .

2 shows adsorption isotherms of uranium occurring in the composite.

Comparative Example 1 Preparation of Functional Composite Using Activated Carbon

Except that the composite was prepared using activated carbon instead of mesoporous carbon as the parent material was carried out under the same conditions as in Example 1.

Comparative Example 2 Preparation of Functional Composite Using Activated Carbon and Experiment of Copper Adsorption

It was carried out under the same conditions as in Example 2 except that the polymer was manufactured using polyethyleneimine (PEI) instead of carboxymethylated polyethyleneimine (CM-PEI) as a functional polymer.

Table 1 summarizes the experimental results of the copper maximum adsorption amount of the composite having a polymer content of 10 wt% and 20 wt% according to Comparative Example 2.

Comparative Example 3 Preparation of Functional Composite Using Activated Carbon and Copper Adsorption Experiment

It was carried out under the same conditions as in Example 2, except that polyacrylic acid (PAA) was used instead of carboxymethylated polyethyleneimine (CM-PEI) as a functional polymer.

Table 1 summarizes the experimental results of the copper maximum adsorption amount of the composite having a polymer content of 10 wt% and 20 wt% according to Comparative Example 3.

Comparative Example 4 Uranium Adsorption Experiment Using Activated Carbon

Except for using F400 as the uranium adsorbent it was carried out under the same conditions as in Experiment 3.

As shown in FIG. 2 , the amount of uranium adsorption increased significantly when the F400 / CM-PEI composite was used as the adsorbent than when the F400 was used as the adsorbent.

As can be clearly seen in FIG. 1 showing the results of Example 1 and Comparative Example 1, it can be seen that the content of polyethyleneimine (PEI) is greatly increased when mesoporous carbon is used as a parent. Table 1 shows that the amount of copper adsorption may vary depending on the type of polymer in the composite containing the same amount of polymer in activated carbon. It can be seen that the amount of copper adsorbed increases when the carboxymethylated polyethyleneimine (CM-PEI) is re-introduced, rather than polyethyleneimine (PEI) or polyacrylic acid (PAA) introduced into activated carbon.

Polymer content in the composite Example 2 Comparative Example 2 Comparative Example 3 10 wt% 20 wt% 10 wt% 20 wt% 10 wt% 20 wt% Copper adsorption amount (copper mg / g complex)  8.3  15  4.2  9  3.5  6.2

As described above, the new functional functional complex according to the present invention can be applied in various chemical environments such as water purification of industrial wastewater, production of ultrapure water, prevention of environmental pollution, and decontamination of radioactive substances, and strong resistance of the mother and functional polymers. Due to the bonding, the mothers have excellent stability in aqueous solution and have a large specific surface area that polymers can access substantially, significantly increasing the amount of functional polymers supported, and high adsorption by using functional polymers that form strong complexes with various metal species. It can be easily separated from an aqueous solution through a simple separation process and can be applied in various chemical environments as a water improver or decontamination agent, and is expected to be advantageous in terms of manufacturing cost.

Claims (13)

A matrix of mesoporous carbonaceous material having an average pore size of 2 nm to 30 nm, and Complex-forming polymer that is strongly adsorbed to the matrix to form a complex with metal ions Functional complex comprising a. The mesoporous carbonaceous material according to claim 1, wherein the mesoporous carbonaceous material includes carbon having a regular pore structure and carbon having an irregular pore structure, hollow and carbon having mesopores in a shell portion, and having a hollow shell. Functional complex, characterized in that at least one selected from the group consisting of carbon having mesopores, derivatives thereof, and mixtures thereof. delete The complex forming polymer of claim 1, wherein the complex-forming polymer is selected from the group consisting of imine polymers, alcohol polymers, acrylic polymers, phenolic polymers, vinyl polymers, nitrile polymers, mixtures thereof, and derivatives thereof. Functional complex characterized in that. The method of claim 4, wherein the complex forming polymer is polyethyleneimine, carboxymethylated polyethyleneimine, polyurethane, polyacrylic acid, polyvinyl alcohol )), Polyiminoacetic acid (poly (iminoacetic acid)), a functional complex, characterized in that at least one selected from the group consisting of their derivatives. The functional composite of claim 1, wherein the functional complex further comprises one or more additives that act as binders to enhance bonding between the parent and the functional polymer. The method of claim 6, wherein the additive is polyvinylpyrrolidone, polyvinylidene fluoride, polyhexafluoropropylene, polyethyl acrylate, polytetrafluoro Functional complex characterized in that at least one selected from the group consisting of polytetrafluoroethylene, polyvinyl chloride, polyacrylonitrile, mixtures thereof and derivatives thereof. Matrix of carbonaceous material, and Carboxymethylated polyethyleneimine that is strongly adsorbed to the parent to form complexes with metal ions Functional complex comprising a. The method of claim 8, wherein the carbon-based material is graphite, carbon fiber, carbon black, carbon nanotubes, activated carbon, mixtures thereof, and mixtures thereof Functional complex, characterized in that at least one selected from the group consisting of derivatives of. The functional complex of claim 8, wherein the molecular weight of the carboxymethylated polyethyleneimine is 1,000 to 1,000,000. The functional complex of claim 8, wherein the molecular weight of the carboxymethylated polyethyleneimine is between 10,000 and 500,000. The functional composite of claim 8, wherein the functional complex further comprises one or more additives that act as binders to enhance bonding between the carbonaceous material and the carboxymethylated polyethyleneimine. The method of claim 12, wherein the additive is polyvinylpyrrolidone, polyvinylidene fluoride, polyhexafluoropropylene, polyethyl acrylate, polytetrafluoro Consisting of polytetrafluoroethylene, polyvinyl chloride, polyacrylonitrile, polybutadiene, polyisoprene, polyacrylic acid, mixtures thereof and derivatives thereof Functional complex, characterized in that at least one selected from the group.

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