JPS59225739A - Fumic acid type adsorbent - Google Patents

Abstract

PURPOSE:To obtain a fumic acid type adsorbent prevented from the elution of fumic acids into a liquid phase and excellent in adsorbing characteristics, by constituting the same from a reaction substance obtained by bonding fumic acids to a vegetable fiber activated through the addition of epichlorohydrine. CONSTITUTION:The titled adsorbent is constituted of a reaction substance prepared by adding fumic acids such as natural fumic acid or nitrofumic acid to a vegetable fiber activated through the addition of epichlorohydrine. Generally, when fumic acids are added to the vegetable fiber, a spacer such as diamines is introduced to facilitate the stereochemical addition of fumic acids. In addition, as a practicial adsorbent, fumic acid content is pref. adjusted to 10-25%. By this method, the elution of fumic acids into a liquid phase can be prevented and the functional groups possessed by fumic acids are not reduced and a fumic acid type adsorbent having excellent adsorbing characteristics can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a humic acid adsorbent, and its purpose is to provide an adsorbent that has excellent adsorption properties for various substances such as heavy metal ions, basic substances, and organic substances such as proteins. There is a particular thing.

Another object of the present invention is to provide a humic acid adsorbent that can effectively absorb useful trace elements.

As is well known, humic acid and nitrophic acid (hereinafter referred to as humic acids) contain large amounts of ligands (hereinafter referred to as functional groups) such as carboxyl groups, phenolic hydroxyl groups, and ether oxygen in their molecules. Various attempts have been made to use acids as raw materials as adsorbents for heavy metal ions.

However, when conventionally known humic acid adsorbents are used in an aqueous solution, they have the disadvantage that they elute, especially when the liquid is alkaline.If even a small amount of humic acid elutes in an aqueous solution,
Even when it is colored yellow (5-20 ppm) or brown (20 ppm or more) and adsorbs gas, humic acid absorbs moisture in the gas phase and is easily eluted, causing the adsorbent to come into contact with it. The drawback is that it stains the area and oozes out. Therefore, it is necessary to carry out post-treatment with activated carbon, but this has the disadvantage of increasing treatment costs.

Therefore, various proposals have been made to improve the dissolution properties of humic acid. For example, methods are known in which humic acid is granulated using a binder such as CMC, a method in which the granules are heat-treated, or a method in which functional groups are protected with magnesium ions or calcium ions and then heat-treated.

However, even if the granules are left unheated or heat-treated, if the heating temperature is as low as 100 to 200°C, elution of humic acid occurs not only in alkaline conditions but also in neutral or acidic areas. . .

Furthermore, if the heating temperature is as high as 300 to 400°C, elution into the liquid phase can be prevented to some extent, but the content of functional groups in humic acid may be significantly reduced by heat treatment, or humic acid may become loose. The disadvantage is that the three-dimensional network structure changes, the original function of humic acid decreases, and therefore the adsorption performance decreases.

Furthermore, attempts have been made to react humic acid with epichlorohydrin or ethylene carbonate to turn it into a resin and make it insolubilized, but even in this case, there is a drawback that the functional groups of the amino acid decrease as described above and the adsorption properties deteriorate.

As a result of research to improve the above-mentioned conventional drawbacks, the present inventors have developed the structure described in the claims.
It was possible to obtain a humic acid-based adsorbent that can prevent elution of humic acids into the liquid phase and has excellent adsorption properties without reducing the functional groups possessed by humic acids.

That is, the present invention is a humic acid-based adsorbent characterized by comprising a reactant in which humic acids such as humic acid or nitrofumic acid are bound to vegetable fibers activated by adding epichlorohydrin.

(3) In general, plant-based fibers are various types of cellulose-based fibers such as wood fibers, cotton, and linen, and even if these plant-based fibers are directly reacted with humic acids, they will not react with humic acids at this rate. It is impossible to do so.

In the present invention, in order to cause the plant fibers to react with nitrofumic acids, the plant fibers were activated by adding epichlorohydrin, and humic acids were successfully added directly to the plant fibers.

In order to activate the vegetable fibers, the vegetable fibers are first subjected to a so-called mercerization treatment in which the fibers are immersed in a concentrated alkaline solution.

Next, the vegetable fibers mercerized as described above are subjected to an addition reaction with epichlorohydrin.

That is, in order to add epichlorohydrin, the mercerized vegetable fiber 'eO,01-40q6 is soaked (4) in an alkaline aqueous solution, preferably 5-20% of sodium hydroxide or potassium hydroxide. By adding 1 to 50% of epichlorohydrin, preferably at a concentration of 10 to 35%, and reacting at room temperature to 100°C, preferably 50 to 90°C, for 10 minutes to 5 hours, preferably 30 minutes to 3 hours, it is easy to form vegetable fibers. Epichlorohydrin can be added to.

As mentioned above, humic acids can be directly and easily added to the vegetable fibers to which epichlorohydrin has been added as follows.

That is, the PH of vegetable fiber added with epichlorohydrin is
7 or more, preferably 13 or more, and a humic acid content of 1 to 40%, preferably 10 to 30%, immersed in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide, and heated at room temperature to 100°C, preferably 70 to 100°C. 30 minutes to 10°C
Humic acids can be easily added to vegetable fibers by reacting for preferably 3 to 10 hours.

Generally, when adding humic acids to vegetable fibers, introducing a spacer makes it easier to add the humic acids stereochemically. Therefore, in the present invention, diamines (trimethylene diamine) are used as spacers instead of adding humic acids directly to the vegetable fibers to which epichlorohydrin has been added as described above.

After introducing tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, etc., the adsorption properties can be further improved by re-adding epichlorohydrin thereto, which is particularly effective for adsorbing organic substances such as proteins. Furthermore, when diamines are used as spacers, humic acids can be added directly to the amino group at the end of the spacer, so depending on the target substance to be adsorbed, it can also be used as an adsorbent without re-adding epichlorohydrin. .

The adsorbent of the present invention can be appropriately selected to have a humic acid content in the range of 1 to 30%, but as a practical adsorbent, it is desirable to have a humic acid content of 10 to 25%.

In the adsorbent of the present invention, the humic acids added to the vegetable fibers are added without almost eliminating the various functional groups of the humic acids; Affinity chromatography is useful for recovering heavy metal ions from aqueous solutions because it is capable of forming salts with chemical substances (including gases), reacting with proteins through hydrogen bonds, and adsorbing other bacteria, viruses, etc. The adsorbent can be used in a wide range of applications, such as as a filler for enzymes and as a carrier for enzyme immobilization, and can be made into an adsorbent with high adsorption efficiency.

The adsorbent of the present invention can be used as it is, but it is more effective if it is made into a woven fabric, nonwoven fabric, or paper-like form as appropriate. Also, socks made from plant-based fibers.

It is also possible to directly add humic acid to processed products such as gauze and clothing via epichlorohydrin (7).

Next, the production method of the present invention will be illustrated, and the adsorption effect of various substances will also be shown.

Production Example 1 39ff cotton: Mercerized by soaking in 1200 m6 of 20% NaOH aqueous solution for one day and night. To this, iomg of water and 20 ml of epichlorohydrin were added, and the mixture was reacted at 70 to 80°C for 2 hours. The cotton activated by adding epichlorohydrin, which had been separated from the F solution and washed with water, was added to 200 ml of a 10 part sodium humate aqueous solution (pH 9,2) and heated at 90°C to 90°C.
The reaction was carried out at 5°C for 3 hours. After 1 liquid separation, Pl-111
Thoroughly wash and immerse in an aqueous sodium hydroxide solution to remove unreacted sodium humate, and then wash with pure water. This is dried at 80°C overnight. The adsorbent thus produced contained approximately 800 humic acids.

Production Example 2 (8) Approximately 3.4 g of cotton activated by adding epichlorohydrin prepared in the same manner as in Example 1 was added to 200 mj+ of a 0.2 M aqueous hexamethylene diamine solution, and reacted at 70°C for 1 hour. . After separating the f-liquid, it was washed with water. The produced amyl/hexylcellulose was diluted with 10% Na0E (aqueous solution 200%
mJ, and 20ml of epichlorohydrin was added to perform a reactivation reaction. When the reactivated cotton into which an aminehexyl group was introduced as a spacer was reacted with humic acid under the same conditions as in Example 1, an adsorbent with a humic acid content of about 10% was obtained.

Regarding the product obtained in Production Example 1, the functional groups of humic acid added were measured and the results are shown in Table 1.

Table 1 □ That is, it is observed that the adsorbent of the present invention retains the functional groups of the raw material nitrofumic acid, with almost no loss of the functional groups of the humic acids added to the vegetable fibers.

Further, the elution of the product obtained in Production Example 2 into an aqueous solution at various pH values was investigated, and the results are shown in Table 2.

Table 2 (Note) *Absorbance is calculated by adding 0.1 ml of adsorbent to an aqueous solution of each pH (p
For H adjustment, use hydrochloric acid or sodium hydroxide) 100mA
After soaking for 2 hours, the supernatant liquid was poured into a cell with a thickness of 35
Measured using 0 nm.

As is clear from Table 2, the present invention is hardly soluble in alkaline aqueous solutions, and there is no problem due to elution within the pH range of 1 to 9.

Next, various adsorption tests were conducted using the adsorbents according to the present invention manufactured in Production Examples 1 and 2 above.

Adsorption test 1 Seawater was filtered through an Nα5C filter, and uranyl acetate was added to it so that the uranium concentration was approximately 5 ppm.
Adjust the pH to 8.2 with sodium carbonate, and add 5 om of this seawater.
After adding lv adsorbent 0.1 g'e and shaking occasionally at room temperature for 5 hours to adsorb uranium and find the adsorption rate, P
The uranium recovered by elution with an aqueous hydrochloric acid solution of I-10.5 was as shown in Table 2.

Table 3 shows that although uranyl carbonate is an extremely strong complex, in this adsorbent, the amine acid dissociates uranyl carbonate,
It can adsorb uranium by forming a uranyl-humic acid complex, and the adsorbed uranium can also be eluted at 100%.
It is recognized that recovery is possible at a high recovery rate.

Adsorption test 2 Using the adsorbents obtained in Production Examples 1 and 2, an adsorption test was carried out on the treated liquid with the composition shown in Table 3, and the results shown in Table 4 were obtained when the treated liquid was investigated. . The adsorption method was as follows: 0.1 !7 of the adsorbent was immersed in 50 ml of the treatment solution and left for 2 hours with occasional shaking.

Table 3 From the above results, Cd in the treatment solution was 95.4%, Hq
It was confirmed that 96.6% of the particles were removed.

Adsorption test 3 Production example 2. adsorbent 1
After filling the tank with ammonia gas and making the ammonia concentration 2 at atmospheric pressure, the tank was sealed, and after being left for 30 minutes, the amount of ammonia adsorption could be determined. Similarly, sulfur dioxide gas was introduced into the desiccator to a concentration of 05, and the results were as shown in Table 5 after being left for 30 minutes.

Table 5 From the results shown in Table 5, it is recognized that the adsorbent of the present invention is also effective as a gas adsorbent.

The adsorbent of the present invention can be used as it is, but it can also be used in the form of woven fabric, non-woven fabric, or paper for use in bedding pants and pads.

Can be used for clothing such as socks and masks, or for shoe underlays, etc.
Moreover, there is no discoloration due to perspiration, etc., which is advantageous.

Adsorption test 4 Fill 20 ml (wet capacity) of the adsorbent of Production Example 2 into a 20 mm diameter x 300 mL column, and reach adsorption equilibrium with albumin, lysotium, and cytochrome C as 0.1% aqueous solutions (adjusted to pH 6), respectively. The adsorption capacity was determined as shown in Table 6 by passing the liquid through the column up to the point where the adsorption capacity was determined.

Table 6 (Unit layer/dry weight 0.1'7) Patent applicant Japan Heavy Chemical Industry Co., Ltd. agent City River Riyoshi (15)

Claims (2)

[Claims] (1) A humic acid-based adsorbent comprising a reactant in which humic acids such as natural humic acid or nitrofumic acid are added to a vegetable fiber activated by adding epichlorohydrin. (2) The humic acid adsorbent according to claim 1, wherein diamines are added as a spacer to the vegetable fiber activated by adding epichlorohydrin.