RU2367598C1 - Method for preparation of modified active charcoal - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method for modified active charcoal preparation at temperature 25.0±0.2°C with ozone-oxygen mixture having ozone 1.5±0.1% vol. during 3 hrs is claimed.

EFFECT: capacity enhancing of charcoal sorption in relation to polar organic substances specifically reacting with sorbent surface.

Description

The invention relates to the field of adsorption technology and can be used to obtain modified activated carbons (MAU) used in water treatment, chemical and pharmaceutical industries.

A known method of producing MAU, according to which active carbons (AC) are sequentially subjected to two-stage treatment with hydrogen peroxide with a concentration of 36% and 10%, followed by drying in air (patent RU No. 2240863, IPC ⁷ B01J 20/20, C01B 31/08, publ. 11/27/2004).

The disadvantage of this method is the need to use aggressive chemicals with a high concentration, the treatment of AC in two stages, drying and the duration of the modification process.

The closest is the method of obtaining MAU, in which activated carbon is blown with air heated to 150-200 ° C for one hour, cooled with air to room temperature, and then subjected to oxidation with an ozone-air mixture with an ozone content of 0.005-0.1% (vol. ) within 2-40 hours. As a result of this treatment, carbon cation exchangers with an NaOH exchange capacity comparable with the capacity of weakly acid cation exchange resins are obtained (SU No. 1261903, IPC ⁷ C01B 31/16, B01J 20/20, publ. 07.10.1986) .

The disadvantage of this method is the length of the modification process, the need to pre-activate the samples with air (heating and subsequent cooling), high energy costs associated with heating the air, high air and ozone-air mixture consumption to create a fluidized bed, loss of activated carbon in the process of modification. In addition, since there is no information on the particle size distribution (granular or powdery ACs were modified), as well as on the nature of the precursor (AC base, wood or coal), the high exchange capacity of carbon cation exchangers obtained after two hours of modification is doubtful.

The objective of the present invention is to significantly increase the adsorption capacity of granular activated carbon in relation to polar organic compounds that specifically interact with the adsorbent surface by reducing the duration of the process, reducing the number of stages and costs of the oxidizing mixture.

The task is achieved by treating activated carbon with an ozone-oxygen mixture under such conditions in which the process of accumulation of oxygen-containing surface groups, proportional to the increase in coal mass, prevails over the process of destruction of the adsorbent.

The method is as follows: activated carbon is oxidized in a thermostatic reactor with constant stirring at a temperature of 25 ± 0.2 ° C with a continuous supply of an ozone-oxygen mixture with an ozone concentration of 1.5 ± 0.1% (volume) for 3 hours. The process is carried out in one stage and is not accompanied by the loss of carbon material.

Example 1

ACs were treated with an ozone-oxygen mixture with an ozone concentration of 0.10 ± 0.02%, 0.5 ± 0.1%, 1.0 ± 0.1%; 1.5 ± 0.1%; 2.0 ± 0.1% and 2.5 ± 0.1% (volume) at 25.0 ± 0.2 ° C in a thermostatic reactor with constant stirring for 1 hour. The data obtained are presented in table 1.

Table 1
Effect of ozone concentration in an ozone-oxygen mixture on the sorption capacity of AC in relation to polar compounds No. p / p ozone concentration,% (vol.) weight gain AC,% increase in the sorption capacity of AC,% ε - caprolactam pyridine aniline one 0.10 ± 0.02 0.02 10.3 20.8 - 2 0.5 ± 0.1 0.09 20.1 70,4 2.2 3 1.0 ± 0.1 0.30 39.7 130.1 8.3 four 1.5 ± 0.1 0.51 70.0 242.9 12.5 5 2.0 ± 0.1 0.82 83,2 291.5 14.3 6 2.5 ± 0.1 -0.08 91.9 330.2 15.0

An increase in the ozone concentration in the ozone-oxygen mixture above 2.0% slightly increases the adsorption capacity of activated carbon with a large expenditure of electricity.

Example 2

ACs were treated with an ozone-oxygen mixture with an ozone concentration of 1.5 ± 0.1% (volume) at a temperature of 15 ± 0.2; 25 ± 0.2 and 35 ± 0.2 ° C in a thermostatic reactor with constant stirring for 1 hour. The data obtained are presented in the table.

table 2
The effect of temperature upon oxidation by an ozone-oxygen mixture on the sorption capacity of AC in relation to polar compounds No. p / p temperature ° C weight gain AC,% increase in the sorption capacity of AC,% ε - caprolactam pyridine aniline one 15 ± 0.2 0.21 52.3 170,2 8.8 2 25 ± 0.2 0.51 70.0 242.5 12.5 3 35 ± 0.2 0.62 78.6 254.7 13.1

An increase in temperature to 35 ± 0.2 ° C slightly increased the adsorption capacity of activated carbon.

Example 3

ACs were treated with an ozone-oxygen mixture with an ozone concentration of 1.5 ± 0.1% (volume) at a temperature of 25.0 ± 0.2 ° C in a thermostatic reactor with constant stirring for 1, 3 and 5 hours. The data obtained are presented in table 3.

Table 3
The influence of the oxidation time of the ozone-oxygen mixture on the sorption capacity of AC in relation to the polar compounds No. p / p the duration of the process, h weight gain AC,% increase in sorption capacity of AC,% ε - caprolactam pyridine aniline one one 0.51 70.0 242.9 12.5 2 3 1,02 371.7 414.3 45.8 3 5 -0.80 206.7 385.7 25.0

When treated with an ozone-oxygen mixture for 5 hours, the process of modifying activated carbon is accompanied by a loss of carbon material due to its oxidative degradation, as well as a decrease in its adsorption capacity.

As a result of the studies, the following modification conditions were selected: oxidation with an ozone-oxygen mixture with an ozone concentration of 1.5 ± 0.1% (volume) at a temperature of 25.0 ± 0.2 ° C for 3 hours.

Using this modification method can significantly increase the adsorption capacity of activated carbon with respect to specifically interacting with the surface of the polar organic compounds.

Claims (1)

A method of producing modified activated carbon by treatment with chemical reagents, characterized in that the activated carbon is subjected to processing in a thermostated reactor with constant stirring at a temperature of 25.0 ± 0.2 ° C with a continuous supply of an ozone-oxygen mixture with an ozone concentration of 1.5 ± 0 , 1 vol.% For 3 hours