RU2367597C1 - Method for preparation of active charcoal - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method for active charcoal preparation includes aspen wood pyrolysis, desintegration of the obtained charcoal up to particle size 0.2-2.0 mm, activation with hydrogen peroxide at temperature 250-300°C and pressure 30-50 MPa during 5-10 min, separation, washing with distilled water and drying.

EFFECT: obtaining of quality charcoal able to effective sorption of the benzene from water media.

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Description

The invention relates to a sorption technique and can be used to produce adsorbent in the form of activated charcoal, used, in particular, for adsorption of benzene from an aqueous medium.

A known method of producing an adsorbent in the form of charcoal from whole wood (V. Vygorodov and others. Technology of chemical production, M., Forestry, 1987, p. 310).

Charcoal obtained from hardwood, has a high adsorption capacity with respect to benzene, which pollutes aquatic environments, and charcoal from soft hardwood adsorbs benzene in the same environments, but over a long period of time, calculated in tens of minutes.

The disadvantage of this method is the use of expensive, severely deficient raw materials of hardwood, the stocks of which with modern management methods are dramatically reduced.

A known method of producing charcoal activated carbon from hardwood raw materials, mainly oak (Bronzov OV and others. Obtaining, the main properties and applications of charcoal. "Timber industry", M., 1979, S. 107-108 - prototype). Activation of charcoal obtained by pyrolysis of hardwood is carried out with water vapor at a temperature of 850-900 ° C.

The disadvantages of this method are the high energy intensity of the activation process, the use of hardwood raw materials, which are scarce and expensive.

The technical task of the invention is to increase the efficiency of the method for producing activated charcoal based on naturally renewable, affordable and cheap resources, which include aspen wood, which can quickly and efficiently sorb benzene from aqueous media while reducing the energy intensity of the activation process, reducing labor costs and ensuring chemical activation of coal, which does not contain toxic products and does not require neutralization.

The stated technical problem is achieved by the fact that in the method of producing activated charcoal, including pyrolysis of wood, grinding the obtained charcoal, its activation, separation, washing with distilled water and drying the final product, aspen wood is pyrolyzed, grinding and separation processes are carried out with the selection of particles with a size of 0.2-2.0 mm, hydrogen peroxide is used for activation, while the activation process of one mass part of the selected charcoal particles is carried out by keeping them in caps ulakh in the presence of 2.5 mass parts of a 10% solution of hydrogen peroxide at a temperature of 250-300 ° C for 5-10 minutes at a pressure of 30-50 MPa.

The invention has the following differences from the prototype:

- aspen wood is pyrolyzed;

- the grinding and separation processes are carried out with the selection of particles with a size of 0.2-2.0 mm;

- hydrogen peroxide is used for activation, while the activation process of one mass part of the selected charcoal particles is carried out by keeping them in capsules in the presence of 2.5 mass parts of a 10% hydrogen peroxide solution at a temperature of 250-300 ° C for 5-10 minutes at a pressure of 30-50 MPa.

This will increase the efficiency of the method for producing activated charcoal based on naturally renewable, affordable and cheap resources, which include aspen wood, which can quickly and efficiently sorb benzene from aqueous media while reducing the energy intensity of the activation process, reducing labor costs and providing chemical activation of coal, which does not contains toxic products and does not require neutralization.

In the patent information fund that we reviewed, no technical solutions were found containing these distinctive features, as well as the totality of these distinctive features.

The invention is applicable and will be used in the industry in 2008.

Table 1 shows the concentration levels of benzene (ppm) in an aqueous solution under the influence of the studied coals for different time intervals. Dose: 0.5 g of test coal in 50 ml of model solution.

Table 2 presents the kinetics of reducing the concentration of benzene in the model solution.

The method was performed as follows.

EXAMPLE.

A method for producing activated charcoal includes pyrolysis of aspen wood, grinding the obtained charcoal, its activation with hydrogen peroxide, separation, washing with distilled water and drying the final product, the grinding and separation processes being carried out with the selection of particles with a size of 0.2-2.0 mm, the activation process of one mass part of the selected particles of charcoal is carried out by keeping them in capsules in the presence of 2.5 mass parts of a 10% solution of hydrogen peroxide at a temperature of 250-300 ° C for 5-10 Inuit at a pressure of 30-50 MPa.

The adsorption properties of the obtained charcoal samples were studied at the St. Petersburg Center for the Study and Control of Water on a model aqueous solution of benzene. Studies were performed using an Agilent 6850 chromatograph.

When conducting experiments to obtain comparative indicators, coals from natural wood of aspen (example 1) and oak (example 2) were used.

The experimental results are presented in table 1.

The qualitative and quantitative picture of benzene adsorption by charcoal samples obtained by examples is obvious from the data in Table 1. To assess the intensity of the adsorption process by various charcoal samples, we introduce the adsorption coefficient K

where K _beg , Ki - respectively, the initial and current concentration of benzene in the studied model solution.

The calculated values of the coefficients K are summarized in table 2.

According to the results of the analysis of the data in tables 1 and 2, it can be seen that activated carbon obtained by the claimed method absorbs 95% of benzene within 5-10 minutes and continues to improve these characteristics in the subsequent time (up to 60 minutes).

Thus, the claimed technical solution allows to increase the efficiency of the method of producing activated charcoal based on naturally renewable, affordable and cheap resources, which include aspen wood, which can quickly and efficiently sorb benzene from aqueous media while reducing the energy intensity of the activation process, reducing labor costs and ensuring chemical activation of coal, which does not contain toxic products and does not require neutralization.

The effect of the claimed technical solution is achieved with the totality of all the claimed features.

Table 1 No. p / p Coal Samples The size of the selected particles of charcoal, mm The ratio of particles of charcoal and peroxide, wt. hours Activation temperature, ° С Activation time, min Duration of purification of contaminated water, min The level of concentration of benzene in an aqueous solution, ppm one 2 3 four 5 6 7 8 one Natural Aspen Charcoal - - - - 0 1,2 5 0.85 10 0.26 thirty 0.16 60 0.12 2 Natural Oak Charcoal - - - - 0 1,1 5 0.04 10 0,025 thirty 0.02 60 0.009 3 Charcoal from aspen obtained by the claimed method 0.2 1: 2,3 250 5 0 1.4 5 0.85 10 0.02 thirty 0.02 60 0.01

Continuation of table 1 one 2 3 four 5 6 7 8 1,0 1: 2.4 275 7 0 1.4 5 0.83 10 0.02 thirty 0.02 60 0.01 2.0 1: 2.5 300 10 0 1.4 5 0.8 10 0.02 thirty 0.02 60 0.01

table 2 N p / p Coal Samples Contact Duration, min 0 5 10 thirty 60 one Natural Aspen Charcoal 1,0 1.5 4,5 7.5 10.0 2 Natural Oak Charcoal 1,0 27.5 44.0 55.0 122,2 3 Charcoal from aspen obtained by the claimed method 1,0 17.5 70.0 77.7 140.0

Claims (1)

A method of producing activated charcoal, including pyrolysis of wood, grinding the obtained charcoal, its activation, separation, washing with distilled water and drying the final product, characterized in that aspen wood is pyrolyzed, grinding and separation processes are carried out with the selection of particles with a size of 0.2 -2.0 mm, hydrogen peroxide is used for activation, while the activation process of one mass part of the selected charcoal particles is carried out by keeping them in capsules in the presence of 2.5 wt.h. 10% hydrogen peroxide solution at a temperature of 250-300 ° C for 5-10 minutes at a pressure of 30-50 MPa.