KR20200082017A - Adsorbent based chitin and Method for preparing the same - Google Patents

Abstract

The present invention relates to a chitin-based adsorbent capable of effectively adsorbing anionic dyes or metals by coating a chitin with a linker and a cationic polymer, and a method for manufacturing the same.
The chitin-based adsorbent of the present invention is formed by coating a cationic polymer thereon after a linker is bonded to a hydroxyl group and an amine group of chitin.
The chitin-based adsorbent of the present invention can be used as a renewable biosorbent by increasing the adsorption rate and desorption rate for anionic dyes.
The present invention can contribute to environmental protection and waste management by recycling chitin, which is mostly discarded due to its small surface area, porosity, and high crystallinity, as a biosorbent.

Description

Adsorbent based chitin and method for preparing the same}

The present invention relates to a chitin-based adsorbent and a method for manufacturing the same, and more particularly, to a chitin-based adsorbent capable of effectively adsorbing an anionic dye or metal by coating a linker and a cationic polymer on the chitin and a method for manufacturing the same.

Over the past decades, dyes have been used in a variety of industries such as textiles, paper, pharmaceuticals, plastics, leather, cosmetics, rubber and food. More than 100,000 different commercial dyes and pigments are used and more than 7105 tonnes are produced worldwide each year. During the textile dyeing process, a large amount of wastewater is generated, and about 10 to 15% of the dye is contained in the wastewater and discharged. Generally, a dye of 1,000 mg/L is used as a dyeing solution, and 100 mg/L remains in the dyeing solution after use. Therefore, the discharge of this dark wastewater suppresses the penetration of sunlight through the water surface, thereby reducing the photosynthetic action of aquatic organisms. In addition, some dyes have been reported to produce toxic, carcinogenic, and mutated intermediates by hydrolysis, oxidation, etc., causing great risk to nature and humans. However, most dyes are difficult-to-decompose synthetic materials composed of chemically complex aromatic molecular structures, and are not easily decomposed or removed by a general wastewater treatment process. Dyeing wastewater can be treated by methods such as coagulation/coagulation, chemical oxidation, adsorption, membrane separation, biological treatment, ozone treatment, photocatalyst, filtration, electrochemistry, membrane treatment, and the like. Among them, the adsorption process is known to be an effective technique with large-scale efficiency, capacity, and applicability for removing dyes as well as the possibility of regeneration, recovery, and recycling of adsorbents. Therefore, it is very important to remove the dye in the wastewater using an adsorption technique in an environmentally friendly manner before discharge into the natural environment.

Chitin is the second most abundant polysaccharide in the world, and is a low-cost, biodegradable and renewable biopolymer with a dense structure including hydroxyl and N-acetyl groups. These natural polymers can be extracted from shells of crustaceans such as fungi, insect exoskeleton and crayfish, shrimp, crab, and are also found in invertebrates such as sponges. Chitin can also be obtained from seafood wastes, and recycling of these solid wastes can contribute to environmental protection and waste management.

Korean Patent Publication No. 10-2001-0094573 discloses a crab skin biosorbent that removes heavy metal ions. The disclosed patent has limitations in adsorption performance because crab shells are not crushed into chitin and are simply crushed to be used as an adsorbent.

The present invention provides a chitin-based adsorbent having improved adsorption performance for anionic dyes.

The present invention provides a method of utilizing chitin, which is rarely used as an adsorbent, as an adsorbent.

The present invention is to provide an eco-friendly adsorbent material using chitin.

One aspect of the invention

Preparing chitin powder to which the linker is bound by reacting by adding chitin powder to the linker solution; And

It relates to a chitin-based adsorbent manufacturing method comprising the step of reacting the chitin powder to which the linker is bound is put into an amine group-containing polymer solution and reacted.

In another aspect, the present invention

Chitin powder (10);

Linker (20) bound to the chitin; And

It is related to a chitin-based cationic adsorbent comprising an amine group-containing polymer layer 30 coated on the surface of the chitin by crosslinking the linker.

The chitin-based adsorbent of the present invention is formed by coating a cationic polymer thereon after a linker is bonded to a hydroxyl group and an amine group of chitin.

The chitin-based adsorbent of the present invention can be used as a renewable biosorbent by increasing the adsorption rate and desorption rate for anionic dyes.

The present invention can contribute to environmental protection and waste management by recycling chitin, which is mostly discarded due to its small surface area, porosity, and high crystallinity, as a biosorbent.

1 and 2 are conceptual diagrams of the chitin-based adsorbent of the present invention.
Figure 3 shows the reaction process of chitin-based adsorbent production.
4 is a FE-SEM measurement of raw chitin, GA-chitin, PEI-chitin.
5 is a graph of FTIR analysis on raw chitin, GA-chitin, and PEI-chitin.
6 is a result of comparing the adsorption amount of each step sample for 100 mg/L AB25.
FIG. 7 is a graph obtained by measuring the amount of dye adsorption according to the pH concentration according to the dye concentration, a of FIG. 8 is desorption efficiency according to the eluent concentration, and b of FIG. 8 is repeated three times to repeat adsorption and desorption. After the adsorption amount and desorption amount is a graph of measurement, Figure 9 shows the isothermal adsorption curve of PEI-chitin according to the temperature (298, 308, 318, 328 K), Figure 10 is a dye of PEI-chitin over time ( AB25) As a result of adsorption experiment, FIG. 11 shows the amount of dye adsorption according to the GA concentration, FIG. 12 shows the amount of dye (RY2) adsorption according to the PEI concentration, and FIG. 13 shows the amount of dye (RY2) adsorption by chitin size Shows

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

1 and 2 are conceptual diagrams of the chitin-based adsorbent of the present invention, and FIG. 3 shows a reaction process of chitin-based adsorbent preparation.

1 to 3, the method for preparing a chitin-based adsorbent of the present invention includes a chitin powder preparation step (hereinafter, a linker-chitin powder preparation step) and a cationic polymer-chitin preparation step in which a linker is coupled.

The linker-chitin powder manufacturing step is a step of reacting the linker 20 solution with chitin powder.

The chitin 10 may be a known chitin powder.

Chitin consists of β-1,4 bonds of N-acetyl-D-glucosamine (GlcNAc), and is structurally very similar to cellulose, but has a structure in which OH at the carbon 2 position of cellulose is substituted with an acetamide group. Have. In addition, chitin does not exist alone in nature, and forms a copolymer with chitosan, showing a difference from cellulose, a homopolymer composed of one type of monomer.

Recently, biosorbents prepared using chitosan have various functional groups and have high adsorption efficiency due to high chemical reactivity and flexible polymer structure, but they are easily dissolved in an acidic solution and difficult to apply to various adsorption processes due to low physical strength.

In order to replace or complement such chitosan, the present invention uses chitin having excellent chemical stability even in various solvents such as acidic, basic and organic solvents as a support for a biosorbent.

The powder size of chitin usable in the present invention may be 100 to 850 µm, preferably 100 to 500 µm, and most preferably 180 to 300 µm. The adsorbent manufacturing process is advantageous when the chitin particle size is in the range of 180 to 300 μm, and it can provide a uniform amount of adsorption when used as an adsorbent.

The linker 20 may include a plurality of reactive moieties (aldehyde group, vinyl group, carboxyl group, oxysilane group, etc.) so as to bind not only chitin but also an amine group-containing polymer. The linker may be a compound having two or more reactive moieties. The linker may have a molecular weight of 50 to 500 g/mol.

The linker 20 is glutaraldehyde, bisdiazobenzidine, triazole dialdehyde, glycidyl methacrylate, benzyltriazole carbaldehyde, benzo Cyazole Carboxyl” benzothiazole carboxaldehyde, epichlorohydrin, dialdehyde, methylene-bis-acrylamide, glyoxal, acrylic acid, maleic acid ( maleic acid), tetraethoxysilane, and tripolyphosphate.

When glutaraldehyde (GA) is used as the linker, GA is bonded to both hydroxy and amine groups of chitin to effectively crosslink large amounts of cationic polymers.

In the step of preparing the linker-chitin powder, the concentration of the linker solution may be in the range of 0.1 to 10% (w/v), preferably 1 to 3% (w/v), and most preferably 3% (w/v). .

Chitin powder may be added to the linker solution in an amount of 0.01 to 0.05 g/mL, preferably 0.03 to 0.05 g/mL, and most preferably 0.05 g/mL.

When the linker concentration exceeds 3% (w/v), adsorption performance may be reduced.

For example, the linker-chitin powder manufacturing step may be stirred for a predetermined time at room temperature using a multi-shaking incubator.

Referring to FIG. 3, the linker may be bound to a hydroxy group or an amine group of chitin.

The cationic polymer-chitin preparation step is a step of reacting the linker-chitin in an amine group-containing polymer solution. In the cationic polymer-chitin preparation step, the cationic polymer may be cross-linked with the linker and coated on the chitin surface.

The amine group-containing polymer usable in the present invention includes polyethyleneimine, amine-terminated polyethylene oxide, amine-terminated polyethylene/propylene oxide, polymers of dimethyl amino ethyl methacrylate, and dimethyl aminoethyl methacrylate and vinyl. It can be selected from the group consisting of a copolymer of pyrrolidone, a linear polymer of epichlorohydrin and dimethylamine, polydiallyldimethylammonium chloride, polyethanolamine/methylchloride and modified polyethyleneimine. The amine group-containing polymer may be polyethyleneimine or modified polyethyleneimine.

The amine group-containing polymer has a cationic charge of 70 mol% or more, and the weight average molecular weight is preferably in the range of 1000 to 200,000.

The cationic polymer-chitin preparation step is a linker-linked chitin powder 0.01 to 0.05 g, preferably 0.03 to 0.05 g, the amine group-containing polymer solution 1 to 20% (w/v), preferably 5 to It can be added to 10% (w/v). The polymer concentration in the amine group-containing polymer solution may be about 1 to 20% (w/v), preferably about 10% (w/v).

If the polymer concentration is over 15% (w/v) or more, the polymer remains chemically unable to bind to the chitin surface, and can be precipitated by reacting with a dye in the adsorption process.

The cationic polymer-chitin production step can be stirred for a predetermined time at room temperature using a stirrer.

1 to 3, the chitin-based cationic adsorbent of the present invention is a chitin powder (10), a linker (20) bound to the chitin, and an amine group-containing polymer layer cross-linked with the linker and coated on the surface of the chitin 30.

The chitin powder particle size may be 100 to 850 µm, preferably 100 to 500 µm, and most preferably 180 to 300 µm.

For the polymer containing chitin, linker, and amine group, the above-mentioned contents can be referred to.

The chitin-based cationic adsorbent of the present invention may be a glutaraldehyde linker, and the polymer layer 30 containing the amine group may be a polyethyleneimine layer.

1 to 3, it was difficult to expect excellent adsorption performance because only a hydroxy group and a small amount of an amine group existed on the surface of the chitin powder. However, the chitin-based adsorbent of the present invention can be coated with a cationic polymer having a large amount of amine groups on the surface to provide a large amount of amine groups on the surface of chitin, thereby significantly improving the adsorption performance.

Example 1

5 g of raw chitin was added to 100 mL of 3% GA solution, and GA-chitin was treated with multi-shaking incubator and GA-chitin was washed with 400 mL of distilled water to surface unreacted GA. It was removed from the, and GA-chitin was immediately transferred to 100 mL of a 10% PEI solution and reacted for 30 minutes at 25°C and 160 rpm. The PEI-chitin separated through solid-liquid separation was washed 3 times with distilled water and freeze-dried at -100°C for 24 hours, and used in the experiment.

Adsorption performance experiment

Various parameters such as pH, dye concentration, time and temperature, which affect the adsorption process, were evaluated through batch adsorption experiments. The experiment was performed under conditions of 160 rpm and 25° C. in a multi-stage shake incubator with 30 mL of dye (Acid Blue 25, AB25, Sigma Aldrich Korea) and 0.02 g of PEI-chitin in a 50 mL polypropylene conical tube.

The pH egde experiment was conducted to investigate the relationship between the final pH and the amount of dye adsorption in dye adsorption of PEI-chitin. Each tube was adjusted with pH of 2 to 12 differently using 0.1, 1, and 5 M HCl and NaOH, and adjusted to maintain the pH of each tube for 24 hours. After reaching the adsorption equilibrium, the final pH was measured.

The adsorption kinetics experiment was performed at initial dye concentrations of 50 mg/L and 100 mg/L to confirm the time required to reach adsorption equilibrium at pH 2. During the course of the experiment, all samples were taken constantly at predetermined time intervals, and each concentration of the obtained samples was analyzed using a spectrophotometer (X-MA3000PC, Human Co., Ltd., Korea).

The isothermal adsorption experiment was evaluated at four different temperatures to evaluate the maximum adsorption amount of PEI-chitin on AB25. The experiment was carried out for 24 hours by varying the initial concentration of the dye from 0 to 300 mg/L at pH 2. Then, an analytical sample was prepared to measure the concentration of the dye remaining in each sample.

Analytical samples were prepared by centrifuging at 9,000 rpm for 5 minutes and then taking only the supernatant and diluting it properly with distilled water. Absorbance analysis was measured with a spectrophotometer at the maximum wavelength of AB25, 600 nm, and the adsorption amount q (mg/g) was calculated using Equation (1).

Here, C _i and C _f (mg/L) mean the initial concentration and final concentration of the dye, and V _i and V _f (L) mean the initial volume and the final volume of the solution. M(g) means the amount of adsorbent used in the experiment.

Desorption and reusability evaluation

PEI-chitin adsorbed on AB25 was prepared by adding 0.02 g of PEI-chitin in a 30 mL aqueous dye solution (100 mg/L) and stirring at pH 2 for 24 hours. Sodium hydroxide (NaOH), sodium hydrogen carbonate (NaHCO3), and sodium carbonate (Na2CO3) were selected as eluents to determine the effective adsorption and desorption conditions of the adsorbed AB25. Did. Desorption efficiency was calculated by the following equation (2).

The reusability evaluation of the adsorbent was evaluated by repeatedly performing the same adsorption experiment and desorption experiment three times. The adsorption experiment was carried out at pH 2, and the desorption experiment was performed under the optimum conditions of the desorption eluent and concentration for each dye.

4 is a FE-SEM measurement of raw chitin, GA-chitin, PEI-chitin. Referring to FIG. 4, in the case of PEI-chitin, it was shown that PEI is well distributed throughout the chitin surface. Image 4c', taken at a magnification of 5,000, shows the above result more clearly and observes that there are larger and more voids on the chitin surface.

5 is a graph of FTIR analysis on raw chitin, GA-chitin, and PEI-chitin. Referring to Figure 5, looking at 3440, 1423, 1129 cm ^-1 representing the amine peak, it can be seen that the intensity of all peaks increases as the step of surface modification progresses, and also cross-linking between amine groups of GA and GA of chitin and PEI The CN peak indicating binding was found at 1635 cm ^-1 , and the intensity of the peak increased as the surface modification step progressed. The main characteristic peaks of PEI, 1423 cm ^-1 (-NH bending and deformation vibration), 1650 cm ^-1 (-NH ₂ or -NH), and 3440 cm ^-1 (NH stretching) show similar peak changes between raw chitin and GA-chitin. However, the peak intensity of PEI-chitin increased significantly. Through this peak change, it can be confirmed that PEI was successfully introduced.

6 is a result of comparing the adsorption amount of each step sample for 100 mg/L AB25. Adsorption amounts of raw chitin, GA-chitin, and PEI-chitin were 55.93, 44.35, and 144.28 mg/g, respectively, and the adsorbent of the present invention, PEI-chitin, had an increase in adsorption capacity of about 2.6 times compared to chitin powder .

7 is a graph measured by experimenting the amount of dye adsorption according to the pH concentration according to the dye concentration. Referring to FIG. 7, the overall adsorption amount change according to pH was highest at pH 2 and the adsorption amount tended to decrease rapidly toward the alkali region. When the dye was low in concentration, it showed high efficiency adsorption capacity over a wide range of pH2-8.

8A is a graph showing the desorption efficiency according to the eluent concentration, and FIG. 8B is a graph measuring adsorption amount and desorption amount after repeated adsorption and desorption 3 times. Referring to a of FIG. 8, NaOH showed the highest desorption rate from 0.01 M to 85.2%, NaHCO3 from 0.01 M to 78.7%, and Na2CO3 from 0.1 M to 47.6%. Referring to b of FIG. 8, the adsorbents of the present invention are slightly lower than the first and second adsorption and desorption amounts, but since the second and third adsorption amounts are similar, it can be confirmed that it can be repeatedly used several times.

Figure 9 shows the isothermal adsorption curves of PEI-chitin according to the temperature (298, 308, 318, 328 K) of the dye (AB25_ in the initial concentration of 0 to 300 mg/L). Various adsorbents and the maximum adsorption amount of the adsorbent (PEI-chitin) of the present invention are summarized.In terms of maximum adsorption amount, PEI-chitin is less than 100 mg/g hazelnut shell (Ref. 1), base treated Shoreadasyphyllasawdust( Reference 2), NaOH-treated Ficusracemose (Ref. 3), water lettuce (Ref. 5), Azollapinnate (Ref. 6) and having a maximum adsorption higher than biofilm (Ref. 7) showing 113.4 mg/g The maximum adsorption amount of Waste tea activated carbon (Ref. 4) was 203.34 mg/g, which was higher than that of PEI-chitin, but the affinity value was found to be relatively low at 0.422 L/mg. It can be confirmed that the sex polymer (PEI)-chitin biosorbent is an excellent adsorbent for the adsorption of the dye (AB25).

Sorbent q _max (mg/g) b _L (L/mg) h (mg/g min) Temperature (K) references. Hazelnut shell 60.2 0.043 7.53 293 [One] BTSD sawdust 24.39 0.430 2.65 300 [2] Ficusracemosa (NTFR) 60.2 0.134 2.38 323 [3] Waste tea activated carbon 203.34 0.422 4.35 303 [4] Water lettuce (WL) 24.5 0.070 2.34 297 [5] Azolla pinnata (AP) 50.5 0.027 0.82 297 [6] Biofilm 113.4 1.23 47.30 303 [7] PEI-chitin 177.32 3.276 8.60 297 Example

[Reference] 1. Ferrero, F., “Dye removal by low cost adsorbents: Hazelnut shells in comparison with wood sawdust,” J.Hazard.Mater.142,144-152 (2007).

2. Hanafiah, MAKM, Ngah, WSW, Zolkafly, SH, Teong, LC and Majid, ZAA,” Acid Blue 25 adsorption on base treated Shorea dasyphylla sawdust: Kinetic, isotherm, thermodynamic and spectroscopic analysis,” J.Environ.Sci. 24,261-268 (2012).

3. Jain, S. N. and Gogate, P. R., “NaOH-treated dead leaves of Ficus racemosa as an efficient biosorbent for Acid Blue 25 removal,” Int.J.Environ.Sci.Technol. 14,531-542 (2017).

4. Auta, M. and Hameed, B. H., “Preparation of waste tea activated carbon using potassium acetate as an activating agent for adsorption of Acid Blue 25 dye,” Chem.Eng.J.171,502-509 (2011).

5. Kooh, MRR, Dahri, MK, Lim, LBL, Lim, LH and Chan, CM, “Separation of acid blue 25 from aqueous solution using water lettuce and agro-wastes by batch adsorption studies,” Appl.WaterSci.8, 61 (2018).

6. Kooh, MRR, Dahri, MK, Lim, LBL and Lim, LH, “Batch Adsorption Studies on the Removal of Acid Blue 25 from Aqueous Solution Using Azolla pinnata and Soya Bean Waste,” Arab.J.Sci.Eng.41 ,2453-2464 (2016).

7.Mawad, A. M. M., Yousef, N. M. H. and Shoreit, A. A. M., “Bioremediation of Acid Blue 25 Dye by Anthracene Degrading Pseudomonas Pseudoalcaligenes ASU-016,” CatrinaInt.J.Environ.Sci.10,53-60(2015).

10 is a result of the adsorption experiment of dye (AB25) of PEI-chitin over time. The experiment was carried out for about 31 hours at 25°C using 50 mg/L and 100 mg/L AB25. Referring to FIG. 10, adsorption was very fast in the initial stage, and after a certain period of time, the adsorption equilibrium was reached after about 120 minutes (50 mg/L) and 500 minutes (100 mg/L). The adsorption amount was about 2 times higher than 50 mg/L from 100 mg/L to 150.38 mg/g, but the time to reach adsorption equilibrium was increased by about 4.2 times.

Example 2

PEI-chitin was prepared in the same manner as in Example 1, except that a linker (GA) having a concentration of 0.1 to 10% was used. After adsorbing the dye (RY2, Reactive Yellow2) under the condition of pH 2 for each PEI-chitin, the adsorption amount was measured, and FIG. 11 shows the amount of dye adsorption according to the GA concentration.

Referring to FIG. 11, when the GA concentration was 3% to a maximum of 304.0 mg/g, and the GA concentration was further increased to 5% and 10%, the adsorption amount tended to decrease again.

Example 3

PEI-chitin was prepared in the same manner as in Example 1, except that each PEI of 1 to 20% was used. After adsorbing the dye (RY2, Reactive Yellow2) under the condition of pH 2 for each PEI-chitin, the adsorption amount was measured, and the adsorption amount of the dye (RY2) according to the PEI concentration was shown in FIG. 12.

Referring to FIG. 12, when the PEI of 1% was used, the adsorption amount significantly increased from 147.1 mg/g to a maximum of 430.7 mg/g when 20% of PEI was used. However, in the sample using PEI of 15% or more in the centrifugation process after the adsorption process, it was confirmed that a cohesive precipitate of dye was formed. This appears to be a phenomenon in which PEI, which is not chemically completely bound to the surface of chitin, is physically bound and is detached from the adsorption process and combined with RY2. This is a phenomenon irrelevant to the adsorption performance of PEI-chitin, and is considered to be a factor that prevents the evaluation of adsorption performance of the developed material. .

Example 4

PEI-chitin was prepared in the same manner as in Example 1, except that the size of the chitin powder was used as a sample for each of five sizes. After adsorbing the dye (RY2, Reactive Yellow2) under the condition of pH 2 for each PEI-chitin, the adsorption amount was measured, and the adsorption amount of the dye (RY2) by chitin size was shown in FIG. 13.

Referring to FIG. 13, as the particle size of chitin decreased, the adsorption amount increased, and the adsorption amount was the highest at 307.8 mg/g when less than 180 μm. However, in the size of less than 180 μm, the adsorbent manufacturing process is not only difficult, but the adsorbed amount of the produced material is not uniform, and thus, in the present invention, chitin having a size of 180 to 300 μm was determined as a preferred size.

In the above, a preferred embodiment of the present invention has been described in detail as an example, but this description is merely to describe and disclose an exemplary embodiment of the present invention. Those skilled in the art will readily recognize that various changes, modifications and variations are possible from the above description and accompanying drawings without departing from the scope and spirit of the invention.

10: chitin 20: linker
30: amine group-containing polymer layer

Claims (13)

Preparing chitin powder to which the linker is bound by reacting by adding chitin powder to the linker solution; And
Chitin-based adsorbent manufacturing method comprising the step of reacting the linker is the chitin powder is bonded to the amine group-containing polymer solution. The method of claim 1, wherein the linker-linked chitin powder production step is characterized in that the concentration of the linker solution is 1-10% (w/v), and the chitin powder is added at 0.01-0.05 g/mL compared to the linker solution. Chitin-based adsorbent manufacturing method. The method of claim 1, wherein in the reaction step, a chitin-based adsorbent production method characterized in that the linker-linked chitin powder 0.01 to 0.05 g is added to the amine group-containing polymer solution 1 to 10% (w/v). The method of claim 1, wherein the chitin-based adsorbent manufacturing method is characterized in that the chitin powder size is 100 ~ 500㎛. The method of claim 1, wherein the linker is a compound having at least one of two or more aldehyde groups, vinyl groups, carboxyl groups, and oxysilane groups. According to claim 1, wherein the linker is glutaraldehyde (glutaraldehyde), bisdiazobenzidine, triazole dialdehyde, glycidyl methacrylate, benzyltriazole carbaldehyde (benzyltiazole carbaldehyde) ), benzocyazole car”K silylaldehyde (benzothiazole carboxaldehyde), epichlorohydrin, dialdehyde, methylene-bis-acrylamide, glyoxal, acrylic acid, A method for preparing a chitin-based adsorbent, characterized in that it is one of maleic acid, tetraetoxysilane, and tripolyphosphate. Chitin powder (10);
Linker (20) bound to the chitin; And
Chitin-based cationic adsorbent comprising an amine group-containing polymer layer 30 cross-linked with the linker and coated on the surface of the chitin. 8. The chitin-based cationic adsorbent according to claim 7, wherein the powder particle size is 100-500 μm. The chitin-based cationic adsorbent according to claim 8, wherein the amine group-containing polymer layer (30) is a polyethyleneimine layer. According to claim 1, wherein the linker is glutaraldehyde (glutaraldehyde), triazole dialdehyde (triazole dialdehyde), glycidyl methacrylate (glycidyl methacrylate), benzyltriazole carbaldehyde (benzyltiazole carbaldehyde), benzocazole Car”K-silaldehyde (benzothiazole carboxaldehyde), epichlorohydrin, dialdehyde, methylene-bis-acrylamide, glyoxal, acrylic acid, maleic acid ), tetraethoxysilane (tetraetoxysilane) and tripolyphosphate (tripolyphosphate), characterized in that any one of chitin-based cationic adsorbent. Contacting the anionic dye or anionic metal ion solution with the adsorbent according to claim 7; And
Adsorption method using a chitin-based adsorbent comprising the step of recovering the adsorbent. 12. The method of claim 11, wherein the contacting step adjusts the pH of the solution to 8 or less. 12. The method of claim 11, wherein the method further comprises the step of desorbing the dye or metal by putting the recovered adsorbent in an alkaline eluent.

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