JP2849706B2 - Adsorbent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an adsorbent.

[0002]

2. Description of the Related Art Chitin is an organic skeleton substance of crustaceans such as crabs and shrimps, and is a nitrogen-containing polysaccharide having a structure similar to cellulose. It is recovered from crab and shrimp shells that have become waste. On the other hand, chitosan is a basic polysaccharide substance obtained by heating and deacetylating chitin in a concentrated alkaline aqueous solution. These chitins and chitosans are called chitinous substances, and are used as ingredients for health foods, and are also used as flocculants and packings for chromatography. On the other hand, carbonization of cellulosic substances such as wood to obtain an adsorbent is widely performed, but it is not known that chitinous substances such as chitin and chitosan are carbonized and surface activated to form an adsorbent. Not been.

[0003]

It is an object of the present invention to provide an adsorbent having better adsorption characteristics than activated carbon formed from cellulosic materials.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, 50 of chitinous substances
An adsorbent comprising activated carbon formed by surface-activating a carbide at 0 to 1000 ° C is provided.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As a chitin substance (chitin and / or chitosan) used as a raw material in the present invention, a substance recovered from the shell of a crab or a shrimp can be used, or the shell itself can be used as a raw material. Can be. When the shell itself is used as a raw material, it may be carbonized as it is or crushed.

The raw material comprising the chitinous substance used in the present invention can be in various shapes such as powder, pellet, flake, coarse particle, fiber, woven fabric and the like. The fibrous raw material can be obtained by once converting a chitinous substance into a solution, discharging the solution in a fibrous form from a nozzle, and solidifying it. The woven material can be obtained by fiberizing the fiber material into a cloth.

[0007] To produce the adsorbent of the present invention, the chitinous substance is carbonized and then surface activated. In this case, the carbonization treatment converts the chitinous substance to an oxygen concentration of substantially zero%.
In an inert gas atmosphere at a temperature of 500 to 1000 ° C, preferably 600 to 900 ° C. As the inert gas, nitrogen gas is generally used. In this carbonization treatment, the chitinous substance is 20 to 32% by weight, preferably 20 to 28% by weight.
To a carbide with a carbon yield of

After the carbonization of the chitinous substance is completed, a gas having reactivity with carbon such as water vapor, carbon dioxide, or oxygen is reacted with the obtained carbonized carbon to obtain activated carbon having an activated surface. it can. The activation process in this case is usually performed at a temperature of 800 to 1100 ° C.

[0009]

Next, the present invention will be described in more detail with reference to examples.

Reference Example 1 A chitin powder was heated to a temperature of 800 ° C. while flowing nitrogen, and kept at this temperature for 30 minutes. As a result, the yield was about 2
Carbide was obtained at 2 wt%. For this carbide, 2
The amount of carbon dioxide adsorbed at 5 ° C. and 1 atm was measured and compared with a typical cell-based activated carbon for gas adsorption G ₂ C (Takeda Pharmaceutical). The carbon dioxide adsorption amount of chitin carbide at a carbon dioxide concentration of 10 vol% is 32.2 mg / g.
Significantly exceeded G ₂ C of 23.4 mg / g. In addition, the carbon dioxide adsorption amount of chitin itself under the same conditions,
It was found that by carbonizing chitin at 11.9 mg / g, it could be converted to a high-performance adsorbent.

Reference Example 2 In the same manner as in Reference Example 1, chitosan was treated with
Carbonized at 00 ° C. The carbonization yield was about 28%. Chitosan at 25 ° C, 1 atm, carbon dioxide concentration 10% vol%
Was 3.3 mg / g, and the adsorption amount of chitosan carbide was 38.3 mg / g. Like chitin, chitosan could be converted to a high-performance adsorbent by carbonization.

Example 1 Activated carbon was produced by reacting a carbide of chitosan at 800 ° C. with steam at a temperature of 850 ° C. (hereinafter referred to as activation). The amount of water vapor sent was 0.16 g / hr, and the water vapor concentration (in nitrogen) was 6.8 vol%. When reacted with steam for 1 hour, activated carbon was obtained with a yield of 70 wt%.
25 ℃ of this activated carbon, 1 atm, carbon dioxide concentration 10vo
The carbon dioxide adsorption amount at 1% is 48.3 mg / g,
It has been found that the activated carbon has a high adsorptivity twice as high as that of a commercially available activated carbon G ₂ C. Furthermore, the activated carbon produced from chitosan was measured for the amount of adsorbed freon (HCFC-142b). Temperature 25 ° C, 1 atm, CFC concentration 29
Fluorocarbon adsorption of chitosan activated carbon at 8 ppm is 10
At 1.8 mg / g, it greatly exceeded that of 73.0 mg / g of G ₂ C.

[0013]

The adsorbent of the present invention has higher performance than activated carbon formed from conventional cellulosic materials,
It is advantageously used in various fields.

Claims (1)

(57) [Claims] 1. An adsorbent comprising activated carbon formed by surface-activating a charcoal of a chitinous substance at 500 to 1000 ° C.