JP2019136668A - Adsorbent and method for producing the same - Google Patents

Abstract

To provide an adsorbent having excellent adsorptivity of a substance which causes malodor.SOLUTION: There is provided an adsorbent composed of a modified cellulose fiber, wherein a cellulose molecule constituting the modified cellulose fiber has a hydrazide group or a hydrazine group and the modified cellulose fiber has an average fiber diameter of 2 to 1000 nm. The cellulose molecule has a carboxylate group and is preferably formed by the bonding of a hydrazide group or an ammonium group through the carboxylate group.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an adsorbent comprising a modified cellulose fiber. The present invention also relates to a method for producing the adsorbent.

  Various odors exist in the living environment, and unpleasant ones are called bad odors. Substances that cause malodor include nitrogen-containing compounds such as ammonia and trimethylamine, sulfur-containing compounds such as methyl mercaptan and hydrogen sulfide, aldehydes such as acetaldehyde, and fatty acids such as isovaleric acid.

  So far, the present inventor has produced a modified cellulose fiber having an average fiber diameter of 2 to 300 nm formed by bonding cellulose molecules constituting the cellulose fiber and a metal phthalocyanine derivative. And it reported that this cellulose fiber can be utilized as a deodorizing material of methyl mercaptan and hydrogen sulfide (Patent Document 1).

  The deodorizing material in Patent Document 1 is excellent in deodorizing performance of methyl mercaptan and hydrogen sulfide. However, among the substances causing bad odor, aldehydes cannot be sufficiently deodorized, and improvement has been demanded.

JP 2017-88697 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an adsorbent excellent in the adsorption performance of a substance that causes malodor. Another object of the present invention is to provide a method for producing such an adsorbent.

  The above problem is an adsorbent composed of modified cellulose fibers; the cellulose molecules constituting the modified cellulose fibers have a hydrazide group or a hydrazine group, and the average fiber diameter of the modified cellulose fibers is 2 to 1000 nm. This is solved by providing an adsorbent.

  At this time, it is preferable that the cellulose molecule has a carboxylate group, and a hydrazide group or a hydrazine group is bonded through the carboxylate group. It is also preferable that the carboxylate group is formed by oxidation of a primary hydroxyl group at the C6 position of a glucose unit that is a constituent unit of the cellulose molecule.

  The carboxylate group is preferably a hydrazinium carboxylate group or an ammonium carboxylate group.

  Furthermore, it is preferable that the cellulose molecule further has a free carboxyl group.

  Aldehyde adsorbents are a preferred embodiment of the present invention. Further, an adsorbent capable of adsorbing ammonia or amine is also a preferred embodiment of the present invention.

  Moreover, the preservation | save method of the fruit which preserve | saves a fruit in presence of the adsorption material of this invention is a suitable embodiment of this invention.

  Moreover, the said subject provides the manufacturing method of the adsorbent characterized by mixing and making the cellulose fiber which has an average fiber diameter of 2-1000 nm, and the nitrogen-containing compound which has a hydrazide group or a hydrazine group react. Is also solved.

  At this time, it is preferable that the said cellulose fiber has a carboxyl group, and the said nitrogen-containing compound has a group which can react with a carboxyl group while having a hydrazide group or a hydrazine group. It is also preferable that the group capable of reacting with the carboxyl group is a hydrazinium group or an ammonium group.

  The adsorbent of the present invention has excellent adsorption performance for substances that cause malodor. In particular, since it is excellent in aldehyde adsorption performance, it is suitable as an aldehyde adsorbent.

2 is a diagram showing the results of infrared spectroscopic measurement of TEMPO-oxidized CNF obtained in Example 1. FIG. In Example 1, it is the figure which showed the infrared spectroscopy measurement result of the adipic acid dihydrazide used as a raw material. 2 is a graph showing the results of infrared spectroscopic measurement of modified CNF-1 obtained in Example 1. FIG. In Example 1, it is a photograph which shows the grape left to stand at room temperature for 15 days. In Comparative example 1, it is a photograph which shows the grape left at room temperature for 15 days.

The present invention relates to an adsorbent comprising a modified cellulose fiber (modified CNF). In the present invention, it is important that the cellulose molecules constituting the modified cellulose fiber have a hydrazide group or a hydrazine group. As a result of intensive studies, the present inventors have found that a modified cellulose fiber having a hydrazide group or a hydrazine group has an excellent adsorption performance for a substance that causes malodor, and has completed the present invention. Here, the hydrazide group refers to a nitrogen-containing functional group represented by —CO—NH—NH ₂ , and the hydrazine group refers to a nitrogen-containing functional group represented by —NH—NH ₂ .

  Hereinafter, the manufacturing method of the adsorbent of the present invention will be described. The adsorbent of the present invention can be obtained by mixing cellulose fibers and a nitrogen-containing compound and reacting them to bond cellulose molecules and nitrogen-containing compounds. A suitable production method is a method in which a cellulose fiber having an average fiber diameter of 2 to 1000 nm and a nitrogen-containing compound having a hydrazide group or a hydrazine group are mixed and reacted.

  The cellulose fiber used in the present invention has an average fiber diameter of 2 to 1000 nm and a fiber diameter smaller than that of normal cellulose fiber such as pulp. Such fine cellulose fibers are called “cellulose nanofibers (CNF)” and are produced by highly fibrillating ordinary cellulose fibers. The average fiber diameter is preferably 800 nm or less, and more preferably 500 nm or less. On the other hand, cellulose fibers having an average fiber diameter of less than 2 nm are difficult to obtain by ordinary methods and are not practical for industrial use. The average fiber diameter is preferably 5 nm or more. The average fiber diameter is a value determined by observing cellulose fibers using a scanning electron microscope.

  CNF used by this invention will not be specifically limited if it has the above-mentioned average fiber diameter, A general fibrillated cellulose fiber can be used. Examples of the raw material for the fibrillated cellulose fiber include wood, straw, bamboo, bagasse, straw, straw, and rice husk. Fibrilization can be performed by applying mechanical shearing force to cellulose fibers having a normal diameter such as pulp using a disk mill, a beater, a homogenizer, or the like. Moreover, fibrillation of cellulose fibers can also be performed by chemical treatment.

  It is preferable that the cellulose molecule of CNF used in the present invention has a free carboxyl group. At this time, it is preferable that the carboxyl group is formed by oxidation of a primary hydroxyl group at the C6 position of a glucose unit which is a constituent unit of the cellulose molecule. Cellulose fibers in which the primary hydroxyl group at the C6 position of the glucose unit has been oxidized can be easily synthesized by using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). By reacting the cellulose molecule with TEMPO, the primary hydroxyl group at the C6 position of the glucose unit can be selectively oxidized to a carboxyl group.

  At this time, the content of free carboxyl groups in the cellulose molecule is preferably 0.1 mmol or more per 1 g of modified CNF. When the content is less than 0.1 mmol, a predetermined amount of hydrazide group or hydrazine group may not be introduced into the cellulose molecule. Moreover, there exists a possibility that the outstanding adsorption | suction performance with respect to ammonia or an amine may not be obtained. The content is more preferably 0.5 mmol or more. On the other hand, the carboxyl group content is usually 5 mmol or less. The content is obtained by a titration method.

  The nitrogen-containing compound to be reacted with CNF is not particularly limited as long as it has a hydrazide group or a hydrazine group. Examples of the nitrogen-containing compound having a hydrazide group include a monohydrazide compound having one hydrazide group in the molecule and a polyhydrazide compound having two or more hydrazide groups in the molecule. Among these, a polyhydrazide compound having two or more hydrazide groups in the molecule is preferable, and a dihydrazide compound having two hydrazide groups in the molecule is more preferable.

  Examples of the dihydrazide compound include adipic acid dihydrazide, succinic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, and the like. Among these, adipic acid dihydrazide is preferable.

  Examples of the nitrogen-containing compound having a hydrazine group include a monohydrazine compound having one hydrazine group in the molecule and a polyhydrazine compound having two or more hydrazine groups in the molecule. Among these, a monohydrazine compound having one hydrazine group in the molecule is preferable.

  In the present invention, the CNF has a carboxyl group, and the nitrogen-containing compound to be reacted with the CNF has a hydrazide group or a hydrazine group and a group capable of reacting with the carboxyl group (hereinafter referred to as a reactive group). Is preferred. Examples of the reactive group include a group capable of ionic bonding with a carboxyl group and a group capable of covalent bonding with a carboxyl group. Of these, the reactive group is preferably a group capable of ionic bonding with a carboxyl group.

  From the viewpoint of reactivity with the carboxylate group, the reactive group is preferably a hydrazinium group or an ammonium group. Of these, the reactive group is more preferably a hydrazinium group.

  The nitrogen-containing compound to be reacted with CNF may have a functional group other than a hydrazide group and a hydrazine group as long as the effects of the present invention are not impaired. Examples of the functional group include a hydroxyl group, a halogen group, an ester group, an amide group, a nitrile group, and a nitro group.

  Thus, modified CNF can be obtained by mixing and reacting CNF and a nitrogen-containing compound. In the modified CNF of the present invention, the content of nitrogen element obtained from elemental analysis (combustion method) is preferably 0.05% by mass or more. When the amount is less than 0.05% by mass, there is a possibility that excellent adsorption performance cannot be obtained for a substance that causes malodor. The content is more preferably 0.1% by mass or more, further preferably 0.5% by mass or more, and particularly preferably 1% by mass or more.

  On the other hand, the content of nitrogen element is usually 20% by mass or less, and preferably 15% by mass or less. Since CNF does not contain a nitrogen element, the nitrogen element detected by the elemental analysis is derived from the nitrogen element contained in the nitrogen-containing compound used for the production of the modified CNF.

  In the present invention, the cellulose molecule constituting the modified CNF has a hydrazide group or a hydrazine group. At this time, the cellulose molecule preferably has a carboxylate group, and a hydrazide group or a hydrazine group is preferably bonded via the carboxylate group, and more preferably bonded via a hydrazide group.

  Further, the carboxylate group is preferably a hydrazinium carboxylate group or an ammonium carboxylate group, and more preferably a hydrazinium carboxylate group.

  The adsorbent of the present invention comprises modified CNF, and the cellulose molecules constituting the modified CNF have a hydrazide group or a hydrazine group. Since the hydrazide group or hydrazine group easily binds to the aldehyde, the adsorbent of the present invention is suitable as an adsorbent for aldehyde. Especially, it is preferable that a cellulose molecule has a hydrazide group from a viewpoint of the adsorption | suction performance of an aldehyde.

  Moreover, it is preferable that the cellulose molecule in this invention has a free carboxyl group further. The carboxyl group easily binds to ammonia or amine. Therefore, since the cellulose molecule has a free carboxyl group, the adsorbent of the present invention can also be used as an adsorbent that can adsorb ammonia or amine in addition to aldehyde.

  Since the adsorbent of the present invention has an excellent adsorbing performance for substances that can cause bad odor, one of the preferred uses is a deodorant. At this time, the form of the deodorizing material is not particularly limited, and may be powdery or solid. Further, a dispersion liquid in which an adsorbent is dispersed in a dispersion medium such as water may be used.

  The method of use is not particularly limited, and the solid or dispersion can be used as it is as a deodorant, or the adsorbent can be applied to a substrate and the substrate can be used as a deodorant. The type of the substrate is not particularly limited, and examples thereof include fabrics such as woven fabrics, knitted fabrics, and nonwoven fabrics, paper, wood, wood powder, plastic, rubber, activated carbon, cement, and plaster. Examples of places where deodorants are used include chemical factories, cleaning factories, sewage treatment plants, hospitals, nursing homes, houses (especially toilets), agricultural products processing plants, and livestock processing plants.

  Moreover, the clothing which has a deodorizing performance can also be obtained by using the fabric which apply | coated the adsorption material of this invention. Furthermore, prevention of sick house syndrome can be expected by using a building material containing the adsorbent of the present invention.

  Another preferred embodiment of the present invention is a method for preserving fruit, wherein the fruit is preserved in the presence of the adsorbent. As demonstrated in the examples described later, the rot of the fruit was suppressed by storing the fruit in the presence of the adsorbent. The reason for this is not necessarily clear at the present time, but it is presumed that the adsorbent of the present invention can effectively adsorb gas generated from fruits.

  The fruit to be stored in the presence of the adsorbent is not particularly limited. The present inventors have confirmed that the rot of grapes can be suppressed. However, not only grapes but also various fruits are expected to have a spoilage inhibiting effect.

Example 1
[Sample synthesis]
(Synthesis of TEMPO oxidized CNF)
Cellulose fibers and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) were reacted to synthesize cellulose fibers oxidized with TEMPO (TEMPO oxidized CNF). The synthesis scheme is shown in the following formula (1).

A specific synthesis method is as follows.
After adding 688 g of aqueous dispersion of cellulose fiber (36 g dry cellulose fiber content), 672 mg (2.08 mmol) tetrabutylammonium bromide, and 1.02 g (9.9 mmol) sodium bromide to a 10 L flask. , 2.5 L of water, and 300 mL of saturated aqueous sodium hydrogen carbonate solution were added to obtain a mixed solution. The aqueous dispersion of cellulose fibers used here was an aqueous dispersion of cellulose nanofibers manufactured by Mori Machinery Co., Ltd. (average fiber diameter: 20 to 200 nm, average fiber length: 500 μm, cellulose fiber content of the aqueous dispersion: 5. 26% by mass).

  Next, while stirring while keeping the liquid temperature of the above mixture at 22 to 25 ° C., TEMPO (508 mg, 3.25 mmol) and sodium hypochlorite aqueous solution 140 mL (commercial product: Cl content: 8.5 to 13.5%) Added dropwise over 5 hours. After dropping, the mixture was further stirred for 2.5 hours while being kept at 22 to 25 ° C. and left overnight.

  After completion of the reaction, 13 mL of 1.0 M sodium thiosulfate aqueous solution was added to the flask to decompose unreacted sodium hypochlorite, and then 153 mL of 6N hydrochloric acid was added. The pH of the mixed solution at this time was 1.58. Next, this mixed solution was filtered under reduced pressure to obtain a solid, and this solid was washed with water to obtain TEMPO oxidized CNF.

The carboxyl group content in the obtained TEMPO oxidized CNF was measured. The measuring method is as follows.
190.7 mg of freeze-dried TEMPO-oxidized CNF was placed in a beaker, and 70 mL of ion-exchanged water was added. A dispersion of TEMPO-oxidized CNF was prepared by adding 1.0 mL of 1M sodium chloride aqueous solution thereto and stirring. To this dispersion, 1.0 mL of 0.1N hydrochloric acid was added to adjust the pH to 2.98. Then, using a burette, a 0.01N sodium hydroxide aqueous solution was dropped into the dispersion, and the conductivity and pH were measured until the pH reached 10.9 to obtain a conductivity curve. The carboxyl group content in TEMPO oxidation CNF was calculated | required from the obtained electrical conductivity curve. As a result, the carboxyl group content in TEMPO oxidized CNF was 1.6 mmol per 1 g of TEMPO oxidized CNF.

In addition, infrared spectroscopic measurement (total reflection method (ATR)) was performed on the obtained TEMPO-oxidized CNF. The results are shown in FIG. As shown in FIG. 1, a peak due to C═O stretching of the carboxyl group of TEMPO-oxidized CNF was confirmed at 1726 cm ⁻¹ .

(Synthesis of modified CNF-1)
TEMPO-oxidized CNF and adipic acid dihydrazide were reacted to synthesize modified CNF-1. The synthesis scheme is shown in the following formula (2).

Here, infrared spectroscopic measurement (ATR) was performed on adipic acid dihydrazide used as a raw material. The results are shown in FIG. As shown in FIG. 2, peaks due to amide C═O were confirmed at 1531 cm ⁻¹ and 1626 cm ⁻¹ .

The synthetic method of modified CNF-1 is as follows.
A dispersion was prepared by dispersing 54 g of TEMPO oxidized CNF (weight in terms of solid content) (carboxyl group content: 1.6 mmol per 1 g of TEMPO oxidized CNF) in 4 L of water. To this dispersion, 810 mL of 0.1 M adipic acid dihydrazide aqueous solution was added and stirred. By adding adipic acid dihydrazide aqueous solution, the pH of the dispersion changed from 3.73 to 4.91. After the dispersion was stirred for 5 hours, water was added to bring the total volume to 5.4 L to obtain modified CNF-1.

The obtained modified CNF-1 was subjected to infrared spectroscopic measurement (ATR). The results are shown in FIG. As shown in FIG. ^3, 1598cm ^-1, a peak derived from C = O was observed at 1630 cm ^-1. Among them, the peak at 1630 cm ⁻¹ is derived from C═O of amide. The peak at 1598 cm ⁻¹ indicates that carboxylate was generated from TEMPO-oxidized CNF carboxylic acid (see FIG. 1). From this, it was found that adipic acid dihydrazide was bound to TEMPO-oxidized CNF.

Further, as indicated by an arrow in FIG. 3, a shoulder peak was observed in the vicinity at 1700 cm ⁻¹ . This shoulder peak is a shoulder peak due to C═O of the carboxyl group in TEMPO-oxidized CNF, and it was also found that the obtained modified CNF-1 contains an unreacted carboxyl group.

(Preparation of cloth coated with modified CNF-1)
An aqueous dispersion in which 1 g (in terms of dry weight) of modified CNF-1 was dispersed in 100 mL of water was prepared. After spraying this dispersion liquid uniformly on both surfaces of a polyester / rayon mixed nonwoven fabric (Nippon Paper Crecia Co., Ltd .: 9 cm × 18 cm), the nonwoven fabric was dried. Next, the amount of modified CNF-1 adhering to the nonwoven fabric was determined from the difference between the weight of the nonwoven fabric after spraying the dispersion and the weight of the nonwoven fabric before spraying the dispersion. The amount of modified CNF-1 attached was 110 mg.

[Gas adsorption test]
(Ammonia gas adsorption test)
In a closed bottle with a capacity of 2.8 L, a cloth coated with modified CNF-1 and a beaker containing 28% aqueous ammonia were placed. Next, an aqueous potassium hydroxide solution was dropped into a beaker containing ammonia water to generate ammonia gas, and then the lid of the sealed bottle was closed. When the concentration of ammonia gas in the sealed bottle was measured using the detection tube, the concentration at the start of the experiment was 80 ppm ("Experiment start (0 minutes)" in Table 1). And the density | concentration of the ammonia gas in an airtight bottle in 15 minutes after 30 minutes and 60 minutes was measured. The results are shown in Table 1.

(Acetaldehyde gas adsorption test)
A beaker containing 1 mL of a cloth coated with modified CNF-1 and an aqueous solution of acetaldehyde (diluted stock solution to 1.5 / 10000) was placed in a closed bottle with a capacity of 2.8 L. At this time, a magnetic stirring bar was also placed in the beaker. Next, after closing the lid of the sealed bottle, the sealed bottle was placed on a magnetic stirrer, and a magnet stirrer in the beaker was rotated to generate acetaldehyde gas in the sealed bottle. After stopping the rotation of the stirring bar, the concentration of acetaldehyde gas in the sealed bottle was measured using a detection tube, and the concentration at the start of the experiment was 18 ppm ("Experiment start (0 minutes)" in Table 1). . And the density | concentration of the acetaldehyde gas in an airtight bottle in 15 minutes, 30 minutes, and 60 minutes after was measured. The results are shown in Table 1.

[Evaluation of preservability of grapes]
(Ball drop evaluation)
Commercially available grapes (variety Delaware from Okayama Prefecture) were obtained. Along with this grape, a cloth coated with modified CNF-1 was placed in a polypropylene container and sealed with a lid (made of polyethylene). And after leaving this container at room temperature for 30 days, the grape was taken out from the container with the panicle. At this time, ball drop evaluation was performed by counting the number of grape grains remaining in the container outside the bunch. The results are shown in Table 2.

(Freshness evaluation)
Commercially available grapes (variety Muscat from Okayama Prefecture) were obtained. Along with this grape, a cloth coated with modified CNF-1 was placed in a polypropylene container and sealed with a lid (made of polyethylene). And after leaving this container to stand at room temperature for 15 days, the grape was taken out from the container with the panicle, and the freshness of the grape was evaluated visually. The results are shown in Table 2 and FIG.

Example 2
(Synthesis of modified CNF-2)
Modified CNF-2 was synthesized by reacting TEMPO-oxidized CNF with the cationized hydrazine shown below. First, a method for synthesizing cationized hydrazine will be described. The synthesis scheme is as shown in the following formula (3).

A specific synthesis method is as follows.
A mixed solution was obtained by adding 5 mL of methanol to 1.01 mg (5.35 mmol) of an 80% aqueous solution of 2,3-epoxypropyltrimethylammonium chloride. The liquid temperature of this mixed liquid was cooled to 0 to 4 ° C., and 702 mg (14 mmol) of hydrazine monohydrate (NH ₂ NH ₂ .H ₂ O) was added dropwise. Next, after stirring for 1 hour while maintaining the liquid temperature of the mixed liquid at 0 to 4 ° C., the liquid temperature was raised to room temperature, and further stirred for 1 hour.

  After concentrating the obtained liquid mixture with a rotary evaporator, 5 mL of tetrahydrofuran was added to this concentrate and coevaporated to remove water. The operation of co-evaporation was repeated several times. The concentrated solution obtained by co-evaporation was dried under high vacuum to obtain 930 mg of cationized hydrazine chloride ((3-hydrazino-2-hydroxypropyl) trimethylammonium chloride) as a pasty oil.

The obtained cationized hydrazine was dissolved in DMSO-d ₆ and subjected to NMR measurement. The results are shown below.
¹ H NMR (DMSO-d ₆ ) δ 2.54 (m, 1H), 3.14 (s, 9H), 3.15-3.32 (m, 2H), 3.41 (m, 1H), 4.22 (m, 1H)
¹³ C NMR (DMSO-d ₆ ) δ 53.5 (3C), 58.6, 63.2, 69.9

In addition, infrared spectroscopic measurement (ATR) was performed on the obtained cationized hydrazine chloride. As a result, a peak derived from a hydroxyl group was observed at 3272 cm ⁻¹ (not shown).

  Next, modified CNF-2 was synthesized by reacting TEMPO-oxidized CNF with the cationized hydrazine hydroxide. The synthesis scheme is shown in the following formula (4). The TEMPO oxidized CNF used here was obtained by the synthesis method described in Example 1.

A specific synthesis method is as follows.
A mixed solution in which the cationized hydrazine chloride was dissolved in 10 mL of methanol was obtained. The liquid temperature of this liquid mixture was cooled to 0-4 degreeC, and 4.8 mL (1N, 4.8 mmol) of cold potassium hydroxide methanol solutions were dripped. Next, the mixture was filtered using a membrane filter (PTFE, 0.45 μm), the membrane filter was washed with a small amount of cold methanol, and cationized hydrazine hydroxide ((3-hydrazino-2-hydroxypropyl) trimethylammonium chloride. Hydroxide) in methanol was obtained. Since this cationized hydrazine hydroxide is unstable, it was immediately used for the next reaction with TEMPO-oxidized CNF.

  A dispersion was prepared by dispersing 3 g of TEMPO oxidized CNF (carboxyl group content: 1.6 mmol per 1 g of TEMPO oxidized CNF) in 300 mL of water. The methanol solution of the cationized hydrazine hydroxide described above was added to this dispersion and stirred. After stirring for 1 hour, modified CNF-2 was obtained. In the obtained modified CNF-2, the nitrogen-containing functional group of the cellulose molecule is a hydrazine group.

The obtained modified CNF-2 was subjected to elemental analysis by a combustion method. A result is shown below (a numerical value is the mass%).
C (carbon): 41.10, H (hydrogen): 5.76, N (nitrogen): 2.03

  Next, in the same manner as in Example 1, a cloth coated with modified CNF-2 was prepared, and a deodorization test was performed using the cloth. The results are shown in Table 1.

Comparative Example 1
In the “deodorization test”, the deodorization test was performed in the same manner as in Example 1 except that a cloth not coated with modified CNF-1 was added. The results are shown in Table 1. Moreover, in the “evaluation of the storage stability of grapes”, the storage stability of grapes was evaluated in the same manner as in Example 1 except that a cloth not coated with modified CNF-1 was placed in a polypropylene container. The results are shown in Table 2 and FIG.

Claims (11)

An adsorbent comprising a modified cellulose fiber;
An adsorbent characterized in that the cellulose molecules constituting the modified cellulose fiber have a hydrazide group or a hydrazine group, and the average fiber diameter of the modified cellulose fiber is 2 to 1000 nm.   The adsorbent according to claim 1, wherein the cellulose molecule has a carboxylate group, and a hydrazide group or a hydrazine group is bonded through the carboxylate group.   The adsorbent according to claim 2, wherein the carboxylate group is formed by oxidation of a primary hydroxyl group at the C6 position of a glucose unit which is a constituent unit of the cellulose molecule.   The adsorbent according to claim 2 or 3, wherein the carboxylate group is a hydrazinium carboxylate group or an ammonium carboxylate group.   The adsorbent according to any one of claims 1 to 4, wherein the cellulose molecule further has a free carboxyl group.   The adsorbent according to claim 1, which is an adsorbent for aldehyde.   Furthermore, the adsorbent of Claim 6 which can adsorb | suck ammonia or an amine.   The preservation | save method of the fruit which preserve | saves a fruit in presence of the adsorption material in any one of Claims 1-7.   The production of an adsorbent according to any one of claims 1 to 7, wherein cellulose fibers having an average fiber diameter of 2 to 1000 nm and a nitrogen-containing compound having a hydrazide group or a hydrazine group are mixed and reacted. Method. The method for producing an adsorbent according to claim 9, wherein the cellulose fiber has a carboxyl group, and the nitrogen-containing compound has a hydrazide group or a hydrazine group and a group capable of reacting with the carboxyl group.   The method according to claim 10, wherein the group capable of reacting with the carboxyl group is a hydrazinium group or an ammonium group.