DE1299289B - Process for the production of adsorbents from particles of carbonaceous material - Google Patents

Description

a molding machine 'to granulate, whereby one constant; nif; 25 {sis 30 ^ 'C heated. After that will be the resulting granules are heated, for example by allowing the granules to pass through an oven with a TcmperaturgeäHe for a certain time during the passage heated from fOO to 3 (K) C to increase the degree of polymerisation of the synthetic resin (im Case of cellulose acetate) to increase or to da-. Resin to partially carbonize (in the case of acrylonitrile).

: ryl nitrile

In another embodiment of the invention becomes a mixture of the above-described particles of carbonaceous material and silicon dioxide or silicates. for example, alumina-silica, silica gel, with the above-mentioned synthetic resin

Burning during activation only about 30%. In this method, the manufacturing cost was high and the apparatus was complicated necessary.

The invention now provides a simple and inexpensive process for the production of adsorbents, the special feature of which is that carbon particles with a diameter of 15-10 ⁷

There is already a method of making one
granulatförtnigen adsorbent known at
the fine carbon particles with a diameter of about 3000 to 5000 Å under heating
about 150 to 200 "C with coal or petroleum tar
were kneaded. The kneaded mixture was then
by means of a press under a pressure of 100 kg / m ² io. The residence time of the granulate in the oven varies ie pressed and. then 4 to 5 hours at about 250 ° C after the resin used as the adhesive and dried to 300 ° C. After that, the -hehan- - amounts to, for example, 20 to 30 minutes for the cellulose mixture in an electric oven or an acetal resin and - for about 2 hours for the acrylonitrile rotary oven. in an oxidizing atmosphere. Burned for 2 to 3 hours at about 900 to 100O'C, and at · 5
After this burning, the mixture was activated by evaporation. Then, to remove the
Ash content washed with water.

So in this known method were a
high pressure and a large amount of heat required. Solution kneaded as an adhesive or binding agent. Then borrowed. In addition, the yield was as a result of the kneaded mixture being formed into granules and

this heated under the same conditions as described above to H) O to 300 ° C.

In the above-mentioned process, the particle size of the silica or silicate is preferably between 600 and 700 Å; the mixture to be kneaded with the resin solution consists of 65 to 75 percent by weight of carbon-containing particles and 35 to 25 percent by weight of silicon dioxide up to 20 -10 ⁷ cm with a 4 to 10% cellulose or silicate. acetate or acrylonitrile resin solution in a quantity- The cellulose acetate used according to the invention

ratio of about 15 to 17 percent by weight, or acrylonitrile resin has a great binding force and based on the cellulose acetate or acrylonitrile resin, a large molecular weight; Based on these Kneads in an organic solvent, which properties will be the pores on the surface Kneaded mixture granulated in a known manner. 35 of the fine carbon particles with a diameter and the granulate is heated to 100 to 300 "C. knife from 50 to 100 Å, which is used for the adsorption force

As a preferred configuration one uses contributing not to be clogged by the resin. Furthermore, as a carbonaceous material a mixture of the resin can in turn on the surface of the 70% carbon particles with a diameter adsorbent fine pores with a diameter of 15-10 ⁷ to 20-10 'cm and 3O "/ o silicon diameter of 10 to Form 20 Å when the solution dioxide or silicate with a diameter of medium is evaporated.

6-10 " ⁶ to 7: 10" ⁶ cm. The resin is, here. The increase in the polymerization strength of the

expediently cellulose acetate resin to such a degree by heating at lower carbonizes that at least part of the resin in the temperature (100 to 120 C) causes another heated granulate remains uncarbonized. Instead of the 45 increase in the binding power and mechanical strength silicon dioxide or silicals can also be used as the aluminum of the resin, while at the same time ensuring the resistance Use aluminum oxide or alumina gel. 'is enlarged against chemical substances. That so

In the process according to the invention, no adsorbent obtained is required at a high temperature pressure and high temperatures, used for below 150 ° C. and is suitable for and moreover, the product has a high 5 ° of a weakly acidic or weakly alkaline adsorbate. mechanical strength and good resistance - due to the partial carbonization of the acrylonitrile resin

According to the invention, 100 to 300 C becomes an increase in heat resistance and resistance to Effects chemicals, although in this case the mechanical strength is somewhat reduced will.

The adsorbent obtained in this way is used at a temperature below 280 ° C. and is suitable favor a strongly acidic or alkaline adsorbate. The solvent used, which in the Veraule of heating can be evaporated at the

against chemical substances. The starting material can be very cheap raw materials such. B. at the Hydrogen production use incidentally formed soot. :

For the purposes of the present invention, cellulose acetate or acrylonitrile is dissolved in one Solvents such as B. methanol, methylene chloride, chloroform, dioxane or an amine. Carbonaceous Particles whose contamination has been removed by chemical substances, or in the

Hydrogen production incidental fine processes according to the invention recovered

Carbon particles with a diameter of.

150 to 200 Å are left for about 30 minutes at one The adsorption properties of the granules Temperature from about 20 to 25 C with a 4 to f> 5 can change slightly by changing the size of the

lO'Voigen solution of the resin mentioned as an adhesive granulate changed and finely powdered adsorbent

kneaded. Thereafter, the kneaded medium obtained in this way is mixed in, its adsorption properties

Mixture by means of a known granulator or different from those of the carbonaceous material

differentiate. For example, silicon dioxide or silicate are suitable for this purpose.

As investigations under the electron microscope have shown, the fine carbon particles have spherical shape with a diameter of about 200 Å. When kneading with the synthetic resin, therefore, particle gaps of about 30 to 60 Å in diameter are formed in the kneaded Product, corresponding to the closest packing in the kneading stage. This will make the kneaded product porous, and in addition, the synthetic resin is extremely fine and intricately porous because of the Evaporation of the solvent forms pores of about 10 to 20 Å in diameter, reducing the adsorptive power is increased significantly.

The invention will now be further explained using the following examples:

example 1

Example of an adsorbent made up of carbon particles and synthetic resin
composed

100 g of fine carbon particles in the form of a by-product soot with a diameter of about 200 Å (in spherical shape) are used as the aggregate. Add one to the soot 4 to 10% solution of cellulose acetate in methanol in an amount of 15 to 17 percent by weight, based on pure cellulose acetate. The amount of synthetic resin added to carbon is to be added varies depending on the application of the adsorbent. The mixture is about 30 minutes kneaded at 20 to 25 C and then the product kneaded in this way by means of a suitable granulator or formed into granules in a molding machine at 25 to 30 "C. The granules are then about Heated for 30 minutes at about 100 to 120 C to evaporate the solvent from the resin and to remove.

The desired adsorbent is thus obtained in an amount of 120 g. The yield is 120%, based on the carbon particles used.

The gaseous solvent is in a recovery device recovered while simultaneously increasing the degree of polymerization of the synthetic resin as an adhesive in this heating process is increased. All of the synthetic resin, the degree of polymerization of which has been increased, remains in the end product. so

The adsorbent according to the invention can best be used in spherical form; one can the adsorbent but also in other forms, for example in cylinder, plate or irregular broken form.

Example 2

Example of an adsorbent composed of carbon particles, synthetic resin and silicate

is composed

70 g of fine particles of the carbonaceous material becomes 30 g of finely powdered silica gel added. The resulting mixture is made in the same manner as in Example 1 with the resin adhesive offset. The proportion of resin binder to be added, the process and the manufacturing conditions are also the same as in

60 Example 1. A yield of 120%, based on the mixture of carbonaceous material and silicate particles used, was obtained.

The end product was processed into granules as in Example 1.

Example 3

Example of an adsorbent made of carbon particles and synthetic resin under partial carbonization of the resin is produced

The desired product is obtained by 81,8g carbonaceous particles to ^{180cm: 1} lO'Voigen a solution of acrylonitrile in dimethylformamide is added, so that a mixture of 81.8 ¹ Vo carbonaceous particles and 18.2% acrylonitrile, based on pure Acrylonitrile. The kneading temperature and the conditions, with the exception of the heating process, are the same as in Example 1. The kneaded product is passed through an oven with a temperature gradient of 100 to 300 ° C. for about 2 hours, during which the resin is partially charred. The product obtained in this example 3 has a somewhat lower mechanical strength compared with the products of examples 1 and 2, but the acid, heat and alkali resistance is greater than that of the products of examples 1 and 2. The product was processed into granules as in Example 1. The yield is 90.0%, based on the carbon-containing particles used.

In order to improve the adsorption capacity of the adsorbent according to the invention compared to conventional, To show known adsorbents, the following experiments were carried out:

1. Substances studied

(1) Granulated commercial activated carbon.
Sample A: activated charcoal from coconut shells.
Sample B: Granulated activated charcoal from charcoal. Sample C: Granulated activated charcoal from charcoal.

(2) The adsorbent produced in accordance with the present invention.

Sample No. 1: Adsorbent made by adding 83.3% carbon black to the total amount, minus the solvent, to a 10% solution of 2-acetyl cellulose in acetone.

Sample No. 2: Adsorbent made by adding 81.8% carbon black to the total amount, minus the solvent, to a 10% dimethylformamide solution of acrylonitrile.

Sample No. 3: Adsorbent made by adding 86.0 "/ o carbon black to the total amount, minus the solvent, to an 8% dioxane solution (or 8% methylene chloride or Methanol solution) of 3-cellulose acetate.

The particle sizes of Sample Nos. 1 to 3 are all in the range between 2.8 and 0.5 mm, and theirs Particle distribution after drying at 100 ° C or the preparation of the sample is as follows:

(3) Particle size distribution:

2.8 to 1.65 mm. 33%

1.65 to 1.17 mm 34%

1.17-0.5mm 33%

2. Packing density

After packing these particles into the graduated cylinder with an inside diameter of 1.5 now

The packing density (g / cm ³ ) was measured in an amount of 25 cm ^{3 with shaking:}

Packing density; ■ ;. .

sample

0.68

0.48

0.52

number 1

0.42

No. 2

0.40

No. 3

0.44

The packing density values of Samples Nos. 1, 2 and 3 according to the present invention are intermediate 0.40 to 0.50, what for the recovery of the Solvent is most appropriate.

3. pH value

1 g each of samples A, B, C, No. 1, 2 and 3 are placed in 100 cm ^{3 of} distilled water (pH value in the range between 5.6 and 5.8) and boiled for 5 minutes. After equalizing the evaporated water and cooling, the pH value was measured using a glass electrode:

PH value

sample

9.6

5.5

6.0

number 1

3.8

No. 2

4.0

4. Surface size

Surface size (ni ^: 'g) ...

A. B. C. sample
Black iron number 1 No. 2 No. 3 12 (K) 1200 1200 300 1200 1200 1200

The surface area of samples No. 1, 2 and 3 carried out 25 50% of the caramet solution. The one here he

according to the present invention is 4 times the surface area of the raw carbon black. this is evidence that a large amount of pores, which is indispensable for adsorption, have been formed.

5. Abrasion resistance

The amount that remains on a sieve with a mesh size of 0.6 to 0.5 mm if 20 g of each sample and 10 steel balls, each with a diameter of 10 mm, are placed in the sieve and Continuously rotating at 60 rpm for 10 minutes was determined as the abrasion resistance.

.

Abrasion resistance

sample

80.5

75.1

82.5

number 1

94.0

No. 2

88.4

No. 3

96.0

Samples No. 1, 2 and 3 according to the invention show a very high mechanical strength compared to the commercially available products.

6. Adsorption equilibrium of caramel

(Standard test method for adsorbents

for liquid phase)

Caramel was in a buffer solution, for example according to Sö re η se η (KHoPO _4. Na ₂ HPOi). dissolved and diluted. Then the color concentration of this solution was measured at 6 (K) in μ with a photoelectric colorimeter. Then 1 g of each sample was placed in 100 cm ^{3 of} this liquid and the adsorption was carried out for 15 hours in a thermostat at 25 ° C. with intermittent shaking.

After the samples had been centrifuged off, the adsorption was determined by colimimetric comparison with the original caramel solution.

The tests were carried out using the same procedure for solutions with a concentration of 25, 33 and The results obtained are listed in Table 1: Table 1

Discoloration of caramel ( ^(l / o) (isotherm at 25 C)

Same A. B. sample C. number 1 No. 2 No. 3 weight con 7.0 15.8 8.0 12.5 11.8 15.9 centering 7.7 19.2 11.3 14.7 15.4 23.1 (%) 8.6 26.9 23.3 20.2 20.2 33.7 25th 16.0 48.0 30.0 33.0 35.7 61.0 33 ' 50 100

The adsorption amounts of the adsorbents produced according to the invention at different concentrations far surpass conventional products.

7. Adsorption of Chlorophyll (Standard Test Method for Liquid Phase Adsorbents)

Adsorption equilibrium at constant temperature

A diluted solution of 200 mg / 1 chlorophyll is prepared by dissolving the chlorophyll in a buffer solution, for example according to Sörensen (KH ₂ PO ₄ , Na ₂ HPO ₄ ). 1 g of each sample is placed in 100 cm ^{3 of} this solution, and then adsorption is carried out at a thermostatically controlled temperature of 25 ° C. for 215 hours, with occasional shaking. The adsorbent is then centrifuged off and the amount adsorbed from the solution is determined colorimetrically. The tests were carried out by the same procedure with a chlorophyll concentration of 100, 50, 25 and 12.5 mg'l. The results are shown in Table 2 below.

Table 2

Adsorption of chlorophyll (mg / g)
(Isotherm at 25 "C)

Same
weight con A. B. sample number 1 No. 2 No. 3 centering 0.25 0.45 0.50 0.55 0.62 (mg / I) 0.35 0.80 C. 0.90 0.92 1.22 12.5 0.50 1.00 0.40 1.35 1.16 2.15 25th 0.95 1.80 0.70 2.40 2.44 3.95 50 2.00 4.00 0.80 4.80 5.21 6.75 100 1.70 200 3.40

The adsorbed at each concentration by the adsorbent prepared according to the invention The amount is far superior to the amount adsorbed on the conventional product.

8. Adsorption of methylene blue

(Standard test method for adsorbents

for liquid phase)

1 g of each sample was placed a 0.02% solution of methylene blue in 100 cm ^3. The solution was adsorbed for 15 hours with occasional shaking. It was then centrifuged off and the amount adsorbed was determined colorimetrically.

The above tests were carried out using the same procedure on 0.01 and 0.005% solutions. The results are shown in Table 3 below.

Table 3

(Adsorption of methylene blue (mg / g)
(Isotherm at 25 ° C)

Same A. B. Prohe number 1 No. 2 No. 3 weight con 2.4 4.0 4.0 3.5 3.8 centering 4.5 7.0 7.2 7.2 7.9 mg / 1 8.3 12.8 C. 14.0 13.7 14.8 50 3.2 100 5.7 200 10.1

The adsorbed by the adsorbent prepared according to the present invention at each concentration The amount is far superior to the amount adsorbed on commercial products.

The pore distribution and thus the properties of the adsorbent can be determined in the case of the invention Change process by partially replacing the carbonaceous material with silica, Replaces silica or alumina gel, which has a different pore distribution and thus different Have adsorption properties.

This results from the following experiments and the drawing:

In the drawing are the adsorption curves for iodine of the above-mentioned sample No. 3, which after the method according to the invention was made from carbonaceous material, and one as well Sample No. 4 produced by the method according to the invention, in which 30% of the carbonaceous Material replaced by silica gel, compared.

As can be seen from the drawing, the adsorption occurs when the iodine concentration is low in the adsorbent No. 4 is much larger than adsorbent No. 3. In contrast, however, the

ίο Adsorption in sample no. 4 proportional low when the iodine concentration is high.

This comparison of Adsorbents Nos. 3 and 4 shows that Adsorbent No. 3 with its large adsorbing ability at large concentration as an adsorbent for adsorbing large molecules is suitable and the No. 4 adsorbent, which has a large adsorbing capacity has a low concentration, is suitable for adsorbing small molecules.

The results of the comparative experiment in the adsorption of iodine on adsorbent No. 3 and 4 are shown below:

Adsorption for iodine

1 g each of samples no. 3 and 4 is placed in 100 cm ^{: i of} a n / 10 iodine solution and left in a thermostat for 15 hours, shaking from time to time. Then it is centrifuged off. 200 cm ^{3 of} the clear supernatant solution are removed and the amount of iodine adsorbed is determined in each case by titration with n / 10 sodium thiosulphate. A corresponding determination of the amount adsorbed was carried out for n / 20, n / 40 and n / 80 iodine solutions. The results are shown by the course of the curve in the drawing.

Claims (4)

Patent claims: 1. A process for the production of adsorbents from particles ■ of carbonaceous material, characterized in that carbon particles with a diameter of 15-10 ⁷ to 20-10 ⁷ cm with a 4- to 10% cellulose acetate or acrylonitrile resin solution in a proportion of about 15 to 17 weight percent, based on the cellulose acetate or acrylonitrile resin, kneaded in an organic solvent, granulating the kneaded mixture in a known manner and the granules are heated to 100 to 300 ⁰ C. 2. The method according to claim 1, characterized in that the carbonaceous material is a mixture of 70% carbon particles with a diameter of 15-10 ⁷ to 20 · 10 ⁷ cm and 30% silicon dioxide or silicate with a diameter of 6 · 10 ^β to 7-10 "cm used. 3. The method according to claim 2, characterized in that the resin up to such Degree of charring means that at least some of the resin in the heated granules remains uncarburized. 4. The method according to claim 2, characterized in that instead of silicon dioxide or silicate alumina or alumina gel is used. 1 sheet of drawings 909529/288