RU2370439C1 - Method of producing modified activated carbon - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of activated carbon. A method is proposed for modifying industrial activated carbon, which involves its treatment with low-concentration effluent of production of ε-caprolactam, containing up to 0.5 g/dm³ caprolactam and up to 0.2 g/dm³ ammonium sulphate, with ratio of mass of carbon (g) to volume of effluent water (cm³) - 1:10 for 24 hours, subsequent drying and heating the carbon to temperature of 250°C in air for 4 hours.

EFFECT: increased sorption capacity of carbon with respect to copper (II) ions.

3 ex, 3 tbl

Description

The invention relates to the field of adsorption technology and can be used to obtain modified activated carbons (MAU) used for the treatment of industrial wastewater from chemical and pharmaceutical industries.

A known method of producing MAU, including impregnation of coal with water or a solution of hydrochloric acid with a concentration of 1-4 wt.% With a ratio of the total pore volume of coal and water or acid 1.0- (0.7-1.0), and then processing coal 9 -15% solution of thermosetting resin in furfural at a weight ratio of coal and solution of 1.0- (0.35-0.68), aging to friability and heat treatment at a rate of temperature rise of 450-900 ° С / hour to 700-900 ° С followed by exposure at this temperature for 0.2-0.5 hours (patent No. 2175885, Russia, MPK ⁷ B01J 20/20, СВВ 31/08, publ. 2001.11.20).

The disadvantage of this method is the high cost of the modifying agent, as well as the duration and complexity of the modification process.

The closest is a method of producing MAU, which includes impregnating activated carbon with a solution of ε-caprolactam with a concentration of 2 g / dm ³ at a ratio of AU: reagent 1:10 for 24 hours under static conditions, filtered, dried and heated at a temperature of 250 ° C for 4 hours in an atmosphere of air, and then carbonized (heating to 900 ° C, heating rate of 10 ° C / min, followed by cooling in a stream of inert gas (argon or nitrogen) (patent No. 2276099, Russia

IPC ⁷ B01J 20/20, СВВ 31/08, publ. 2006.05.10).

The disadvantage of this modification method is the significant consumption of reagents, heat, electricity and inert gas.

The objective of the present invention is to increase the sorption capacity of activated carbons for copper, reducing the consumption of electricity, reagents, inert gas and the elimination of toxic waste.

The task is achieved by treating industrial activated carbon (AC) with a low-concentration effluent from the production of ε-caprolactam containing CL up to 0.5 g / dm ³ and ammonium sulfate up to 0.2 g / dm ³ , with the ratio of coal mass (g): volume of wastewater (cm ³ ) - 1:10 for 24 hours, further drying and heating of coal at a temperature of 250 ° C in air for 4 hours.

As a comparison, used industrial activated carbon brand AG-OV-1.

Example 1

ACs were treated with a low-concentration effluent from ε-caprolactam production for 24 hours, then dried and warmed up at 250 ° С in air for 4 hours, while the ratio of coal mass (g): volume of wastewater (cm ³ ) was 1: 5; 1:10; 1:20. Then, on modified samples, adsorption was carried out under static conditions from aqueous solutions of copper nitrate with a concentration of 25 mmol / dm ³ . The data obtained are presented in table 1.

Table 1 The influence of the ratio of the mass of coal (g): the volume of wastewater (dm) in the process of modifying the AC on the adsorption of copper (II) ions No. p / p AU: reagent ratio increase in the sorption capacity of AC,% one 1: 5 15.3 2 1:10 30,0 3 1:20 31,2

Example 2

ACs were treated with a low-concentration effluent from ε-caprolactam production with the ratio of coal mass (g): wastewater volume (cm ³ ) - 1:10 for 24 hours, then the coal was dried and warmed in air at a temperature of 100 ° С, 250 ° С, 500 ° C for 4 hours. Then, on modified samples, adsorption was performed under static conditions from aqueous solutions of copper nitrate with a concentration of

25 mmol / dm ³ . The data obtained are presented in table 2.

table 2 The effect of temperature in the process of AC modification on the adsorption of copper (II) ions from solutions. No. p / p Temperature ° C increase in the sorption capacity of AC,% one one hundred 11.3 2 250 30,0 3 500 coal burns out to a large extent

Example 3

ACs were treated with a low-concentration effluent from ε-caprolactam production with the ratio of coal mass (g): wastewater volume (cm ³ ) -1: 10 for 24 hours, then the coal was dried and heated in air at a temperature of 250 ° С for 2, 4, and 6 hours. Then, on modified samples, adsorption was carried out under static conditions from aqueous solutions of copper nitrate with a concentration of 25 mmol / dm ³ . The data obtained are presented in table 3.

Table 3 The influence of the heating time in the process of AC modification on the adsorption of copper (II) ions from solutions No. p / p Warm-up time, h The increase in the sorption capacity of AC,% one 2 15.7 2 four 30,0 3 6 32,3

As a result of the studies, the following modification conditions were selected: treatment of AC with a low-concentrated effluent from the production of ε-caprolactam containing CL up to 0.5 g / dm ³ and ammonium sulfate up to 0.2 g / dm ³ , with the ratio of coal mass (g): volume waste water (cm ³ ) - 1:10 for 24 hours, further drying and heating of coal at a temperature of 250 ° C in air for 4 hours.

Extraction of copper ions by the obtained sorbents increases by 30%.

Claims (1)

A method of obtaining modified activated carbon, including processing a solution containing caprolactam, drying and heating in air at a temperature of 250 ° C for 4 hours, characterized in that the solution containing caprolactam uses wastewater from ε-caprolactam production containing up to 0 5 g / dm ^{3 of} caprolactam and up to 0.2 g / cm ^{3 of} ammonium sulfate, the treatment being carried out for 24 hours with a ratio of the mass of coal in grams to the volume of wastewater in cm ³ equal to 1:10.