KR20160113375A - Chitosan Core-shell adsorbent and method for preparing the same - Google Patents

Abstract

The present invention relates to a chitosan-based high-performance core-shell adsorbent, having improved adsorption properties and affinity with respect to an anionic metal by impregnating an amine group-containing cationic polymer, and relates to a manufacturing method thereof. According to the present invention, the manufacturing method of the core-shell adsorbent uses chitosan, an eco-friendly material, as a shell, and is an eco-friendly and economic method by minimizing a manufacturing process and the use of a toxic organic solvent. In addition, the adsorbent of the present invention with a core-shell structure enables a core having adsorption functions to be protected by a chitosan-shell, and provides excellent adsorption performance during the reuse. In addition, the adsorbent of the present invention has a core-shell bead structure, thereby being used and collected in various types of adsorption processes in an easy manner.

Description

A core-shell adsorbent based on chitosan and a method for preparing the same,

The present invention relates to a high-performance core-shell adsorbent based on chitosan and a method for producing the same, and more particularly, to a chitosan-based high-performance core-shell adsorbent having improved adsorption performance and affinity for an anionic metal by supporting an amine- Shell adsorbent and a method for producing the same.

In various industrial fields, heavy metals such as lead, mercury and cadmium or wastewater containing valuable metals such as gold, platinum and iridium are generated. When such heavy metals or valuable metal-containing wastewater flows into the water system, serious pollution is caused to destroy the aquatic ecosystem and harmful effects to human beings by bioconcentration. Thus, an effective method is being sought.

As a method for removing contaminants such as heavy metals and valuable metals in industrial wastewater, a chemical treatment method, a physico-chemical treatment method, and a biological treatment method are used.

Domestic Application No. 2010-49870 discloses a metal recovery apparatus such as a ruthenium including a chlorine electrolytic tank (an apparatus for generating chlorine gas using an electrochemical reaction and injecting it into a leaching tank). However, this method is complicated and requires mass production There are difficult disadvantages.

Domestic Application 10-2009-50033 discloses a method for recovering valuable metals such as ruthenium from waste scrap through leaching, precipitation and reduction of alkali molten salt. The above patent discloses a separation method by a chemical precipitation method which not only has a low separation and recovery rate but also repeatedly performs dissolution-condition-chemical precipitation (crystallization), resulting in excessive consumption of reagents, increase in process cost due to long- And a poor working environment due to discharge.

Thus, conventional methods of treating heavy metals and valuable metals have a disadvantage in that they are expensive to operate or have poor process efficiency, and in particular, produce intermediate products that are harmful to human bodies.

An object of the present invention is to provide an environmentally friendly high performance adsorbent capable of effectively treating refractory pollutants such as heavy metals or valuable metals.

The present invention is to provide a high performance adsorbent which can maintain adsorption performance even when reused.

The present invention provides a high performance adsorbent that is easily applied to the adsorption process and is easily recovered.

One aspect of the present invention is

Adding a cationic polymer to the chitosan solution to prepare a polymer mixed solution; And

Dropping the polymer mixed solution into a gelated solution having polyvalent anions in a bead form and reacting,

Wherein the reaction step comprises the step of the cationic chitosan moving and coagulating to form a shell as the gelling solution diffuses into the bead and the cationic polymer remaining in the bead to form a core Core-shell adsorbent material.

In another aspect,

A core carrying a cationic polymer having a molecular weight of 50,000 or more: and

The shell surrounds the core and comprises sodium polyphosphate and chitosan. The shell relates to a core-shell adsorbent material formed by aggregation of anionic polyphosphate and cationic chitosan with electrostatic attraction.

The method of producing a core-shell adsorbent according to the present invention uses environmentally friendly chitosan as a shell, minimizes the use of toxic organic solvents and minimizes the manufacturing process, and is environmentally friendly and economical. In addition, the adsorbent of the present invention is a core-shell structure in which a chitosan-shell protects a core having an adsorption function and can provide excellent adsorption performance even when reused. In addition, since the adsorbent of the present invention has a core-shell bead structure, it can be easily used and recovered in various adsorption processes.

1 is a schematic diagram showing that the mixed solution is changed into a core-shell structure.
Fig. 2 shows the adsorbent of the core-shell structure produced according to the present invention.
3 is a photograph of the capsule obtained in Example 1 and Comparative Example 1 cut.
Fig. 4 shows the maximum adsorption amount in Experiment 1. Fig.
5 shows the maximum adsorption amount in Experiment 2.
6 shows the results of the experiment in Experiment 3.

Hereinafter, the present invention will be described in more detail.

1 is a schematic diagram showing that the mixed solution is changed into a core-shell structure. Fig. 2 shows the adsorbent of the core-shell structure produced according to the present invention.

1 and 2, the method for producing a core-shell adsorbent of the present invention includes a mixed solution preparation step and a reaction step.

Preparation of polymer mixed solution

The step of preparing the polymer mixed solution is a step of preparing a polymer mixed solution by adding a cationic polymer to the chitosan solution.

The chitosan may have a molecular weight of 10,000 to 1,000,000.

The chitosan has a structural formula in which an acetyl group present in chitin is removed. However, the deacetylation of chitin is not complete. In general, chitosan is a polymer mixed with chitin and deacetylated chitin. Chitosan is generally characterized by the degree of deacetylation and is insoluble in water but soluble in most acidic media at a pH of about 6.5 or less (which may range from about pH 6.2 to pH 6.5, depending on the amine content of the chitosan).

The chitosan that can be used in the process of the present invention has a degree of deacetylation of at least 90%, preferably at least 95%. When the degree of deacetylation of chitosan is 90% or less, bubble is not formed as bead shape filled with hollow.

The chitosan which can be used in the present invention may have a molecular weight of 10,000 to 1,000,000, preferably 30,000 to 500,000, more preferably 50,000 to 250,000.

The chitosan may be selected from the group consisting of water, lactic acid, citric acid, malic acid, oxalic acid, acetic acid, tartaric acid, adipic acid, Succinic acid, maleic acid, glutamic acid, fumaric acid, pyruvic acid, gluconic acid, citric acid, picric acid, acid, aspartic acid, terebic acid, and the like.

  The cationic polymer may be an amine group-containing cationic polymer. Wherein the cationic polymer is selected from the group consisting of polyethyleneimine, amine-terminated polyethylene oxide, amine-terminated polyethylene / propylene oxide, polymer of dimethylaminoethyl methacrylate, and copolymer of dimethylaminoethyl methacrylate and vinylpyrrolidone , A linear polymer of epichlorohydrin and dimethylamine, polydiallyldimethylammonium chloride, polyethanolamine / methyl chloride, and modified polyethyleneimine.

The cationic polymer may have a weight average molecular weight of 50,000 or more.

The polymer mixed solution is a mixture of chitosan and a cationic polymer in a solvent. In the chitosan solution, 0.1 to 10 wt% of chitosan is dissolved in the solvent and 0.01 to 5 wt% of the cationic polymer is dissolved in the chitosan solution.

Reaction step

The present invention includes a step of dropping the polymer mixed solution into a gelling solution having polyvalent anions and reacting the solution.

As the gelling solution having a polyvalent anion, sodium polyphosphate may be used.

The reaction step includes a step in which the cationic chitosan migrates and coagulates to form a shell as the gelling solution diffuses into the bead, and the cationic polymer remains in the bead to form a core .

FIG. 1 is a schematic diagram showing a mixed solution changing from a bead shape to a core-shell structure. FIG. Referring to FIG. 1, the chitosan polymer (A) and the cationic polymer (B) are dissolved in acetic acid to form a gel-type polymer network (bead form). When the anionic TPP (C) is gradually diffused into the bead, the cationic chitosan polymer chain (A) existing inside due to the electrostatic attraction is adsorbed on the bead surface (C) The density of the polymer in the vicinity of the surface increases to form a shell.

However, unlike chitosan, the cationic amine group-containing polymer (B) does not migrate to the surface of the beads but remains therein.

The adsorbent of the core-shell structure of the present invention is formed as the cationic polymer constituting the core and the chitosan forming the shell exhibit different behaviors in the reaction step.

The reaction step can be stirred for 30 minutes or longer, preferably 30 minutes to 2 hours. If the reaction time is less than 30 minutes in the reaction step, the shell may be loose and it may be difficult to maintain its shape.

Crosslinked body  Processing and Acid treatment

The present invention further includes a step of treating the adsorbent material with a cross-linking agent after the reaction step and acid-treating the adsorbent material.

The crosslinking agent may be at least one member selected from the group consisting of glutaraldehyde, isocyanide derivatives and bisdiazobenzidine.

  The crosslinking agent may be used in a concentration of 0.01 to 5% (v / v), preferably 0.1 to 1% (v / v).

The acid treatment is a step of treating the adsorbent capsule with sulfuric acid or the like.

In another aspect, the present invention relates to a core-shell adsorbent. The adsorbent comprises a core carrying a cationic polymer having a molecular weight of 50,000 or more, and a shell surrounding the core and containing sodium polyphosphate and chitosan.

The shell is formed by aggregation of anionic polyphosphate and cationic chitosan with electrostatic attraction.

As described above, the cationic polymer forms a core. The core can adsorb anionic, valuable metals, heavy metals, and the like. In addition, since the chitosan-shell protects the adsorption core, excellent adsorption performance can be provided even when reused.

In addition, since the adsorbent of the present invention has a core-shell bead structure, it can be easily used and recovered in various adsorption processes.

With respect to the adsorbent, the adsorbent production method described above may be referred to.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

Example  One

0.3 ml of polyethylenimine (PEI) was added to 10 ml of a chitosan solution containing 2 g of chitosan dissolved in 100 ml of 2% (w / v) acetic acid and sufficiently stirred. Here. The above solution was added dropwise to 500 ml of a 2% (v / v) TPP (sodium tripolyphosphate) solution to form droplets, followed by solidification for 2 hours. Glutaraldehyde was added and crosslinked for 1 hour. Subsequently, sulfuric acid was added thereto and acid treatment was carried out. Finally, the collected capsules were lyophilized.

Comparative Example  One

The procedure of Example 1 was repeated except that no cationic polymer (polyethylenimine, PEI) was added.

Fig. 3 is a photograph of a capsule obtained by cutting one capsule in Example 1 and Comparative Example 1. Fig. 3, in the case of Comparative Example 1 in which only the chitosan solution was dropped, a hollow chitosan bubble was formed (FIG. 3 a), and in Example 1 in which PEI was dropped together, a cationic polymer (PEI ) Can be produced. At this time, the internal cationic polymer and the external chitosan shell part are clearly distinguished.

Experiment 1: Adsorption amount evaluation

Adsorption evaluation method: H ₂ PtCl ₆ nH ₂ O (n = 5.5) was dissolved in a 0.1 M HCl solution to prepare a solution having a Pt concentration of 50 to 1000 mg / L. 0.03 g of a commercially available ion exchange resin (MonoPlusTP214, Lanxess, Germany) was added to 30 ml of this solution, and the mixture was stirred at 25 rpm for 24 hours at 120 rpm. The concentration of the solution before and after the adsorption was measured by ICP-AES and the adsorption amount was calculated.

Fig. 4 shows the maximum adsorption amount in Experiment 1. Fig. Referring to FIG. 4, the adsorbent of Example 1 exhibited a platinum maximum adsorption amount of 815.2 mg / g, which is about 2.5 times higher than the adsorption amount of commercial ion exchange resin of 330.2 mg / g.

Example  2, Example  3, Comparative Example  2

Core-shell capsules with the following conditions were obtained in Example 1 with different PEI contents.

Example 2: Core-shell adsorbent having 1% (v / v) of PEI supported therein

Example 3: A core-shell adsorbent having 3% (v / v) of PEI supported therein (in Examples 2 and 3, it was solidified for 2 hours and then treated with glutaraldehyde in the order of acid treatment)

Comparative Example 2: Treatment of core-shell structure in which 3% (v / v) of PEI was loaded and acid treatment followed by glutaraldehyde treatment

Experiment 2: Evaluation of adsorption amount Example  2, 3, Comparative Example  1, 2)

Adsorption evaluation method: H ₂ PtCl ₆ nH ₂ O (n = 5.5) was dissolved in a 0.1M HCl solution to prepare a 1000 mg / L solution of Pt concentration. To 30 ml of this solution, 0.03 g of each of the ion exchange resins (MonoPlusTP214, Lanxess, Germany) and the commercially available ion exchange resins of Examples 2 and 3, Comparative Examples 1 and 2 were added and stirred at 25 rpm for 24 hours at 120 rpm. The concentration of the solution before and after the adsorption was measured by ICP-AES and the adsorption amount was calculated.

5 shows one point check in Experiment 2. 5, the adsorbent of Example 3 exhibited a maximum adsorption capacity of platinum of 389.1 mg / g, which was about two to three times higher than that of Comparative Example 1 and Comparative Example 2. FIG.

Experiment 3; 10cycle  Adsorption amount evaluation

Adsorption evaluation method: H ₂ PtCl ₆ nH ₂ O (n = 5.5) was dissolved in 0.1 M HCl solution to prepare a 100 mg / L solution of Pt concentration. 1 g of the material of Example 1 was added to 100 ml of this solution and stirred at 25 rpm for 24 hours at 100 rpm. The concentration of the solution before and after the adsorption was measured by ICP-AES and the adsorption amount was calculated (once).

Subsequently, 100 ml of the fresh solution was added, and the same adsorption reaction was carried out to calculate the adsorption amount (twice). In this way, 10 adsorption reactions were carried out.

6 and Table 1 show the results of the experiment in Experiment 3. Referring to FIG. 6 and Table 1, the platinum adsorption efficiency of the adsorbent prepared in Example 1 was maintained at 97.45 ± 0.011 or more during 10 cycles, and the residual amount of platinum in each reaction tank was 2.39 g / L or less The platinum adsorption ability of the material is excellent.

[Table 1]

Hereinafter, specific embodiments of the present invention have been described. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (9)

Adding a cationic polymer to the chitosan solution to prepare a polymer mixed solution; And
Dropping the polymer mixed solution into a gelated solution having polyvalent anions in a bead form and reacting,
Wherein the reaction step comprises the step of the cationic chitosan moving and coagulating to form a shell as the gelling solution diffuses into the bead and the cationic polymer remaining in the bead to form a core ≪ / RTI > wherein the core- The method of claim 1, wherein the chitosan solution is prepared by dissolving 0.1 to 10 wt% of chitosan in a solvent and 0.01 to 5 wt% of a cationic polymer in the chitosan solution. The method of claim 1, wherein the cationic polymer is selected from the group consisting of polyethyleneimine, amine-terminated polyethylene oxide, amine-terminated polyethylene / propylene oxide, polymer of dimethylaminoethyl methacrylate, Wherein the core-shell adsorbent is at least one selected from the group of linear polymers of epichlorohydrin and dimethylamine, polydiallyldimethylammonium chloride, polyethanolamine / methyl chloride and modified polyethyleneimine, Method of manufacturing a material. The method of claim 1, wherein the cationic polymer has a weight average molecular weight of 50,000 or more. The method of claim 1, wherein the chitosan is prepared by deacetylation of chitin and has a deacetylation degree of 90% or more and a weight average molecular weight of 10,000 to 1,000,000. The method of claim 1, wherein the gelled solution is a sodium polyphosphate solution. The method for producing a core-shell adsorbent material according to claim 1, wherein the reaction step is carried out for at least 30 minutes. The method of manufacturing a core-shell adsorbent material according to claim 1, further comprising the step of treating the adsorbent material with a cross-linking agent and acid treatment after the reaction step. A core carrying a cationic polymer having a molecular weight of 50,000 or more: and
Wherein the shell surrounds the core and comprises sodium polyphosphate and chitosan, wherein the shell is formed by aggregation of anionic polyphosphate and cationic chitosan with electrostatic attraction.

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