JPH01207141A - Compound adsorbent and its production - Google Patents

Abstract

PURPOSE:To improve mechanical strength and adsorption capacity, etc., of a compound adsorbent by covering the surface of a particulate base material with an insoluble polymer having pyridinium groups and comprising a copolymer of vinyl pyridine with a crosslinking divinyl monomer. CONSTITUTION:Vinyl pyridine and a crosslinking divinyl monomer are adhered to the surface of a particulate base material such as silica gel, synthetic zeolite, natural zeolite, alumina, etc. The monomers are copolymerized, and obtd. copolymer is then treated with a quaternizing agent. Thus, a compound adsorbent covered with an insoluble polymer formed on the surface of the particulate base material and comprising a copolymer of vinyl pyridine with a crosslinking divinyl monomer and having pyridinium groups, is obtd. Suitable vinyl pyridine is 2-vinyl pyridine, etc., and suitable crosslinking divinyl monomer is divinyl benzene, divinyl toluene, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel composite adsorbent and a method for producing the same. More specifically, the present invention relates to a composite adsorbent that is particularly suitable as an anion adsorbent and has excellent mechanical strength, adsorptivity, and resistance to expansion and contraction, and a method for efficiently producing the same. be.

Conventional technology In recent years, ion exchange resins have been widely used in various fields, including water treatment, separation and purification of amino acids and nucleic acid-related substances in the food field, and antibiotics in the pharmaceutical and biochemical fields. It is used for decolorizing and desalting substances, enzymes, proteins, etc., and as separation carriers for chromatography in the field of analytical chemistry.

These ion exchange resins are generally classified into strongly acidic cation exchange resins, weakly acidic cation exchange resins, strongly basic anion exchange resins, and weakly basic anion exchange resins, depending on the type of exchange group, physical structure, degree of crosslinking, etc. It can be roughly divided into four types.

Among these ion exchange resins, strong basic ion exchange resins include, for example, quaternized copolymers of vinylpyridine and crosslinkable divinyl monomers such as divinylbenzene. .

However, this material has the drawbacks that it is inferior in mechanical strength, expansion and contraction resistance, adsorption properties, etc., is expensive, and is difficult to use industrially as an anion adsorbent as it is. .

Problems to be Solved by the Invention The present invention overcomes the drawbacks of conventional strongly basic ion exchange resins, has excellent mechanical strength, adsorption properties, and resistance to expansion and contraction, and is particularly effective as an adsorbent for anions. The purpose of this invention is to provide a composite adsorbent that can be suitably used industrially.

Means for Solving the Problems The present inventors have conducted intensive research to develop a composite adsorbent having the above-mentioned excellent characteristics. discovered that the objective could be achieved by coating the copolymer with a copolymer and further treating this copolymer with a quaternizing agent.Based on this knowledge, the present invention was completed. I ended up doing it.

That is, in the present invention, the surface of a powdery substrate is made of a copolymer of vinylpyridine and a crosslinkable divinyl monomer,
The present invention also provides a composite adsorbent in which a pyridinium group is coated with an M insoluble polymer.

According to the present invention, this composite adsorbent is produced by adhering vinylpyridine and a crosslinkable divinyl monomer to the surface of a powdery substrate, then copolymerizing the copolymer, and then adding a quaternizing agent to the copolymer. It can be manufactured by processing using.

The present invention will be explained in detail below.

The powdery substrate used in the present invention is made of an inorganic or organic material with a large surface area, and examples of such materials include silica gel, synthetic zeolite, natural zeolite, molecular sieves, alumina, carbon black, activated carbon, and cellulose. Examples include those consisting of employment. One type of each of these substrates may be used,
Two or more types may be mixed and used.

Examples of the vinylpyridine used in the present invention include 2-vinylpyridine and 4-vinylpyridine, which may be used alone or in combination of two or more. Furthermore, examples of crosslinkable divinyl monomers include aromatic divinyl compounds such as divinylbenzene, divinyltoluene, and divinylnaphthalene, and aliphatic divinyl compounds such as ethylene glycol diacrylate and ethylene glycol dimethacrylate. These may be used alone or in combination of two or more. The ratio of this to the vinylpyridine is appropriately selected depending on the desired degree of crosslinking.

In the present invention, first, on the surface of the powdery substrate,
Vinyl pyridine and a cross-linkable divinyl monomer are attached and copolymerized. For example, a method for attaching these monomers is to add the required amount of vinyl pyridine and cross-linkable divinyl in an appropriate low-boiling organic solvent. A method can be used in which a mixed solution is prepared by adding the system monomers, a powdery substrate is added thereto for impregnation, and then the organic solvent is removed by means such as reduced pressure. When preparing the mixed solution, a polymerization initiator is usually added, and there is no particular restriction on the solid content concentration in this mixed solution.

As the polymerization initiator, any conventional radical initiator can be used, such as benzoyl peroxide, azobisisobutyronitrile, potassium persulfate, and the like. These polymerization initiators are usually used in an amount of 0.5 to 5% by weight relative to the amount of vinylpyridine used.

Examples of organic solvents include low-boiling compounds such as methanol, ethanol, acetone, and diethyl ether.

In this way, the vinylpyridine and crosslinkable divinyl monomer adhering to the surface of the granular substrate are heated in the gas phase and copolymerized. The polymerization temperature should normally be higher than the decomposition temperature of the polymerization initiator;
Selected within the range of 00°C.

Polymerization may be carried out by keeping the contents stationary, or
You can also stir and shake the mixture.

The amount of vinylpyridine used in the present invention is as follows:
It is preferably 0 parts by weight or less and 1 part by weight or less.

If this amount exceeds 20 parts by weight, the powdery substrate will adhere and aggregate, making it impossible to obtain a uniform composite in many cases, which is not desirable.

In this way, the surface of the powdery substrate is coated with the copolymer of vinylpyridine and crosslinkable divinyl monomer.

In the present invention, it is necessary to further treat this copolymer with a quaternizing agent. As the quaternizing agent,
For example, alkyl halides such as ethyl bromide, butyl bromide, octyl bromide, dodecyl bromide, benzyl bromide, ethyl chloride, butyl chloride, octyl chloride, dodecyl chloride, benzyl chloride, aryl halides, aralkyl halides, etc. used.

The quaternization treatment is usually carried out by adding the above copolymer-coated composite and the quaternization agent into a suitable solvent such as dimethylformamide, methanol, or ethanol, and heating the mixture. This reaction may be carried out while the mixture is kept stationary, or may be carried out while stirring or shaking. In order to carry out the reaction uniformly and efficiently, the above-mentioned solvents are usually used, but these solvents are not essential.

The amount of the quaternizing agent used is appropriately selected depending on the content of pyridine units in the copolymer. In this way, a composite adsorbent is obtained in which the surface of a powdery substrate is uniformly and firmly coated with an insoluble polymer having a pyridinium group.

Effects of the Invention The composite adsorbent of the present invention is made by uniformly and firmly coating the surface of a powdery substrate with a strongly basic anion exchange resin, and has a small volume change due to swelling in water, and is mechanically resistant. It has extremely superior characteristics compared to conventional strongly basic anion exchange resins, such as high chemical strength and the ability to adsorb various food anions extremely quickly, making it an ideal adsorbent for anions. Suitably used.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 4-vinylpyricine 3. Ot, divinylbenzene 0.0
55', azobisisobutyronitrile 0.03F and diethyl ether 30g were placed in a reaction container, and 20f of silica gel sized into 100-200 meshes was placed in this solution.
was added and soaked. After that, the diethyl ether was evaporated under reduced pressure at room temperature, and then nitrogen gas was introduced to bring the pressure to normal pressure.Then, the mixture was left in a thermostat at 80°C for 5 hours to form 4-vinylpyridine and divinylbenzene on the silica gel surface. Composite 22 in which the surfaces of silica gel particles are substantially coated with vinylpyridine-divinylbenzene copolymer is obtained by polymerizing
．． I got 8t.

Next, this complex was added to a pressure-resistant reaction vessel containing 250 methanol, 10F octyl bromide was added, and after sealing the vessel, a reaction was carried out at 80°C for 5 hours. After the reaction, the complex was washed with methanol and diethyl ether, and then
After drying, a quaternized complex 25.59 was obtained.

As a result of differential thermal analysis of this material, it was found to be 230 to 730℃.
An exothermic peak and weight loss due to oxidative decomposition of the quaternized copolymer were observed, and from these values it was found that the copolymer content in the quaternized composite was 21.6% by weight. Furthermore, the quaternization rate in this copolymer was determined by potentiometric titration of free bromine ions, and was found to be 71%.

This quaternized composite has a dry volume of 1.4 c1d/f and a wet volume of 1.6 m/f, and hardly swells in water, even when vigorously stirred or stirred in water. Its shape remained unchanged and its mechanical strength was good. Furthermore, the anion exchange capacity of this product was measured by a conventional method and was found to be 0.62 meq/l.

When quaternization was carried out using ethyl bromide, butyl bromide, octyl chloride, and octyl iodide in place of octyl bromide, the quaternization rates were 76%, 78%, and 65%, respectively.
68 m, the anion exchange capacity of the obtained quaternized complex is 0.65, 0.68, 0.56, and 0.58 m, respectively.
It was eq/l.

Comparative Example 1 4-vinylpyridine 3. Of Tosivinylbenzene 0.
05t was polymerized to produce a copolymer sized to 100 to 200 meshes, which was quaternized with octyl bromide.

This quaternized copolymer has a dry volume of 1.5 m/f and a wet volume of 38. At Oc1d/t, it gelled and swelled in water, broke when stirred or stirred, and its mechanical strength was extremely poor.

Example 2 A similar experiment was carried out using alumina, natural zeolite, and activated carbon instead of silica gel in Example 1, and a composite coated with vinylpyridine-divinylbenzene copolymer was obtained, which was then brominated. Quaternized with octyl. The results were summarized and shown on the robe.

Example 3 Quaternized complex 1 with octyl bromide obtained in Example 1
．． 02 was added to 5001 nt of a potassium dichromate aqueous solution with an Or concentration of 1Oη/l, and stirred at room temperature for 30 minutes.
After measuring the equilibrium pH of the solution, the Or concentration in the solution was measured, and the removal rate was determined from this value. The quaternized complex has a pH of 3
It quickly adsorbed Cr2O7 in a wide pH range of ~pH7.5, and showed a removal rate of 99% or more.

Comparative Example 2 Using the quaternized copolymer 1.02 produced in Comparative Example 1,
It was operated in the same manner as in Example 3. The sampled solution was destroyed by stirring and the gel-like copolymer was dispersed.
After centrifuging this solution, the Or concentration in the solution was measured. The adsorption rate of quaternized copolymer is slow and the removal rate is 70%.
It was below.

Example 4 Quaternized composite based on the natural zeolite obtained in Example 2 1. Of, culomg7t Cu-EDT
The A complex aqueous solution and the PO5509/l metaphosphoric acid aqueous solution were each added to 500 ml of water, the pH of the solution was adjusted to 3.5, and the mixture was stirred at room temperature for 30 minutes to determine the removal rate of each. The quaternized complex is Cu-EDTA complex and PO]
All of them were quickly adsorbed and showed a removal rate of 95 or more.

Patent applicant Kozo Iizuka, Director of the Agency of Industrial Science and Technology

Claims (1)

[Scope of Claims] 1. A composite adsorbent in which the surface of a granular substrate is coated with an insoluble polymer comprising a copolymer of vinylpyridine and a crosslinkable divinyl monomer and having a pyridinium group. . 2. A patent characterized in that vinylpyridine and a crosslinkable divinyl monomer are attached to the surface of a powdery substrate, then copolymerized, and then this copolymer is treated with a quaternizing agent. A method for producing a composite adsorbent according to claim 1.