RU2240863C1 - Modified activated carbon preparation method - Google Patents

Abstract

FIELD: carbon materials.

SUBSTANCE: method comprises consecutive two-step treatment of activated carbon with 36% and 10% hydrogen peroxide solutions.

EFFECT: increased sorption capacity with regard to polar compounds specifically interacting with sorbent surface.

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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, 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 with a weight ratio of coal and solution of 1.0- (0.35-0.68), aging to friability and heat treatment with a temperature rise rate of 450-900 deg / h to 700-900 ° C subsequent exposure at this temperature for 0.2-0.5 hours (patent No. 2175885, Russia, IPC ⁷ B 01 J 20/20, C 01 B 31/08, publ. 20.11.2001).

However, this method is associated with a high consumption of reagents, the cost of electricity for heat treatment, and is also characterized by the duration of the modification process and the high toxicity of the reagents used.

The closest is the method of obtaining MAU, in which granular activated carbon (AC) is impregnated with a saturated solution of rhodanide ammonium, rhodanide potassium or urea, incubated for 5-6 hours and subjected to heat treatment at a temperature of 310-370 ° C for 2.5-3 hours ( patent No. 2089496, Russia, IPC ⁶ C 01 B 31/08, publ. 09/10/1997).

The disadvantage of this method is the need for energy costs for heat treatment and the release of toxic oxides of nitrogen and sulfur when heating coals.

The aim of the present invention is to increase the sorption capacity of activated carbons in relation to polar compounds that specifically interact with the surface, eliminating the consumption of electricity and toxic waste.

This goal is achieved by sequential two-stage treatment of AC with hydrogen peroxide with a concentration of 36% (coal to hydrogen peroxide ratio 1: 1.3) for 2.5 hours and a 10% hydrogen peroxide solution (AC: hydrogen peroxide ratio - 1: 3) for 1.5 hours. The method is carried out at the first stage by wetting activated carbon with 36% hydrogen peroxide solution at a ratio of 1.3 dm ^{3 of} reagent per 1 kg of activated carbon. After the gas evolution ceases, the coal is treated with a 10% hydrogen peroxide solution at a ratio of 3 dm ^{3 of} reagent per 1 kg of activated carbon and kept until gas evolution ceases. Then the coal is dried in air at room temperature.

Example 1

AC was treated with hydrogen peroxide (36%) with a ratio of coal and hydrogen peroxide 1: 1; 1: 1.3 and 1: 1.5 until the end of gas evolution. Then the coal was dried at room temperature and adsorption was carried out from aqueous solutions under static conditions of ε-caprolactam with a concentration of 0.8-9.0 mmol / dm ³ and pyridine with a concentration of 2.5 · 10 ^-3 -45 mmol / dm ³ . The data obtained are presented in table 1.

Example 2

AU was treated with 10; 25 and 36% hydrogen peroxide solution with a ratio of coal and hydrogen peroxide 1: 1.3 to the end of gas evolution. Then the coal was dried at room temperature and adsorption was carried out from aqueous solutions under static conditions of ε-caprolactam with a concentration of 0.8-9.0 mmol / dm ³ and pyridine with a concentration of 2.5 · 10 ^-3 -45 mmol / dm ³ . The data obtained are presented in table 2.

Example 3

AU was subjected to sequential treatment with 36% hydrogen peroxide at a ratio of coal and reagent 1: 1.3 for 2.5 hours and a 10% hydrogen peroxide solution at a ratio of AU: hydrogen peroxide 1: 1, 1: 2, 1: 3 and 1: 4 until the end of gas evolution. Then the coal was dried at room temperature and adsorption was carried out from aqueous solutions under static conditions of ε-caprolactam with a concentration of 0.8-9.0 mmol / dm ³ and pyridine with a concentration of 2.5 · 10 ^-3 -45 mmol / dm ³ . The data obtained are presented in table 3.

As a result of the studies, the following modification conditions were selected: two-stage sequential treatment of active carbons with a solution of hydrogen peroxide with a concentration of 36% (AC: reactant ratio 1: 1.3) for 2.5 hours and 10% (AC: reactant ratio 1: 1 , 3) for 1.5 hours, followed by drying at room temperature.

Claims (1)

A method of obtaining modified active carbons by treatment with chemical reagents, characterized in that the active carbons (AC) are subjected to a two-stage treatment with 36% hydrogen peroxide with an AC: reagent ratio of 1: 1.3 for 2.5 hours and then 10% a solution of hydrogen peroxide at a ratio of AC: reagent - 1: 3 for 1.5 hours, followed by drying in air.