JPH0810614A - Carbonaceous separation agent having molecular sieve capacity - Google Patents

Abstract

PURPOSE:To obtain a carbonaceous separation agent having useful molecular sieve capacity by using a waste ion exchange resin as a raw material. CONSTITUTION:A carbonaceous separation agent having molecular sieve capacity is obtained by heating a waste ion exchange resin to 300-900 deg.C in inert gas to bake the same. By this constitution, waste can be reutilized as a separation agent having a variable use and the conservation of resources and preservation of environment are effectively achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the reuse of waste ion exchange resins, and more particularly to a carbonaceous separating agent having a molecular sieving ability, produced from waste ion exchange resins.

[0002]

2. Description of the Related Art Ion exchange resins utilize their ion exchange ability to separate impurities in water to produce pure water and soft water, remove specific ions to purify waste water, and identify from the liquid. It is used for various purposes such as concentration and separation of substances and purification of substances. Usually, when the ion exchange capacity of the ion exchange resin decreases during use, it is regenerated with a regenerant and used repeatedly. However, when the ion exchange resin is contaminated, the ion exchange capacity cannot be recovered sufficiently, or when it is crushed or when the regeneration is not repeated, the ion exchange resin becomes a waste ion exchange resin. The waste ion exchange resin is currently disposed of as landfill as industrial waste. Recently, recycling of waste ion-exchange resin has been studied, and it has been proposed to carbonize the waste ion-exchange resin and use it as an activated carbon material (Proceedings of the 4th Conference of the Japan Society for Waste Management, 2nd session).
Pp. 85-288).

[0003]

When the waste ion-exchange resin is landfilled, it is necessary to pay sufficient attention to environmental protection, and there is a problem of a shortage of landfill. Is desired. The above-mentioned proposed method for producing activated carbon is performed by treating the waste ion exchange resin in the air at 500 to 70%.
Heat treatment at 0 ° C to carbonize, and use activating gas for 9
Activated carbon is produced by activation treatment at 00 ° C. Practical application is desired from the viewpoint of recycling the waste ion exchange resin. It is an object of the present invention to provide a separating agent which is made from a waste ion exchange resin and can be produced relatively easily and has a function different from that of activated carbon, that is, a molecular sieving action. It should be noted that, by burning a new ion exchange resin, catalyst (Japanese Patent Publication No. 58-13488) and activated carbon (Japanese Patent Publication No. 5-6)
9768) is also known, but the production of separating agents with molecular sieving ability is not known.

[0004]

The present invention is a carbonaceous separating agent having a molecular sieving ability, which is obtained by heating a waste ion exchange resin to a predetermined temperature in an inert gas and calcining it. The waste ion exchange resin used in the present invention may be an anion exchange resin or a cationic one, and its history of use is not limited. For example, pure water production equipment, soft water production equipment,
The waste ion exchange resin used in the sugar production process, other separation, concentration, purification, etc. and discarded can be used as a raw material. The ion exchange resin is usually a granular particle in which a cross-linking copolymer of styrene and divinylbenzene is used as a base material and a functional group serving as an ion exchange group is introduced.

It is important to use a waste ion exchange resin for the separating agent having a molecular sieving ability of the present invention, and a new resin has a low carbonization yield, and it is difficult to produce a separating agent having a molecular sieving ability. In the production of the separating agent, the waste ion-exchange resin is packed in a heat-resistant column, and the temperature is sequentially raised to a predetermined temperature in an inert gas, for example, in a nitrogen stream, and then baked. The heating rate varies depending on the raw material, but is 5 to 50 per minute.
A temperature of about ℃ is preferable for uniform baking and improvement of strength.

The calcination temperature can be selected from any temperature in the range of 300 to 900 ° C., but it is appropriately set according to the waste ion exchange resin of the raw material and the optimum temperature is selected according to the desired pore size of the separating agent. . 600 ° C or higher is preferable,
At 600 ° C or lower, carbonization may be insufficient depending on the raw material. When the waste ion-exchange resin is fired as described above, the waste ion-exchange resin is carbonized and becomes particles that shrink but contract their original shape. The particles have a molecular size-like almost uniform pore and exhibit a molecular sieving action, and exhibit different performance from ordinary activated carbon having a broad pore up to a relatively large pore size. The particles having a molecular sieving action of the present invention are similar to ordinary molecular sieving agents such as separation of nitrogen and oxygen, selective adsorption of carbon dioxide, selective separation of methane and ethane from a mixed gas of methane, ethane, butane, benzene and the like. It can be applied to various purposes.

[0007]

Industrial Applicability According to the present invention, the waste ion exchange resin can be reused as a separating agent having a useful application and is not only effective for resource saving and environmental protection, but also the separating agent of the present invention can be produced by a simple process. It has a strength comparable to that of commercially available molecular sieves.

[0008]

[Examples] Table 1 shows the elemental analysis values and uses of the used ion exchange resin (crosslinked copolymer of styrene and divinylbenzene) and the new ion exchange resin (the same base material) used for comparison.

[Table 1] Each ion-exchange resin was filled in a tube, placed in a furnace, and heated at a rate of 10 ° C./minute while flowing nitrogen gas from one side of the tube, heated to 300 to 900 ° C. Different samples were prepared. 2 of 4 gases for each sample
Measure the adsorption isotherm at 5 ℃ with a constant volume adsorption amount measuring device,
The Dubinin-Astakhov equation is applied to this to determine the limit adsorption volume, which is the molecular diameter of the adsorbed molecule (carbon dioxide: 0.33 nm, ethane: 0.4 nm, butane:
The pore volume distribution was obtained by expressing the total volume of pores having a size of 0.43 nm and isobutane: 0.5 nm or more. The results are shown in FIG. At the firing temperature of 300 ° C., the waste resins A and B have pores formed therein. At 600 ° C., pores are formed in all of the waste resins A, B and C. At 900 ° C., the pore diameter shifts to the smaller side, and shrinkage of pores around 0.4 nm and micropores of about 0.33 nm are generated.

For reference, the graph of 900 ° C. in FIG. 1 is a commercially available molecular sieve carbonaceous separator (indicated as MSC in the figure).
The cumulative pore volume distribution of It can be seen that A and B have almost the same pore distribution as this commercially available product. Further, in the sample in which the new resin A'corresponding to the waste ion exchange resin A (waste resin A) was carbonized at 300 ° C, almost no pores were generated, and the new resin B'corresponding to the waste resin B was generated.
In the sample (1), the pore volume distribution is broad and the molecular sieving ability cannot be expected (see FIG. 1, carbonization temperature 300 ° C.). Further, the results of thermogravimetric changes in the above heat treatment (carbonization) are shown in FIG. The waste ion exchange resin A has a carbonization yield of about 6 at a temperature of 300 ° C to 900 ° C.
It became 0% to 40%. On the other hand, in the case of a new resin equivalent to the waste ion exchange resin A, the carbonization yield becomes 0 at about 410 ° C,
Only the ash changed. Further, it can be seen that the carbonization yield of the waste ion exchange resins B and C and the new resin thereof is superior to that of the waste ion exchange resins. Next, the following test was performed using the separating agent sample carbonized and prepared at 900 ° C. as described above. 1 g of sample is precisely weighed and 200
After vacuum deaeration treatment was carried out at 0 ° C. for 2 hours, the amount of carbon dioxide and methane adsorbed at a pressure of 600 mmHg was measured. The measurement is performed by an automatic adsorption amount measuring device (BELSORP 28
It was measured at an adsorption temperature of 25 ° C. using a product manufactured by Nippon Bell. The results were as follows. From the above results, it is clear that the separating agent of the present invention exhibits molecular sieving ability.

[0010]

[Brief description of drawings]

FIG. 1 is a graph showing a cumulative pore volume distribution of a carbonized sample for each carbonization temperature, in which the horizontal axis represents pore diameter [nm] and the vertical axis represents pore volume [cc / g].

FIG. 2 shows thermogravimetric change curves of waste resin and new resin for each resin, where the horizontal axis is the carbonization temperature [° C.] and the vertical axis is the weight (W) after carbonization with respect to the initial weight (W0). is there.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Kamiko 3-4-7 Nishi-Shinjuku, Shinjuku-ku, Tokyo Kurita Industry Co., Ltd.

Claims (1)

[Claims] 1. A waste ion exchange resin containing 300 in an inert gas.
To 900 ° C, a carbonaceous separating agent having a molecular sieving ability, which is obtained by heating to a predetermined temperature and baking.