Method for preparing active carbon from municipal sludge by two-step thermal decomposition

A technology for preparing activated carbon and municipal sludge, which is applied in the field of activated carbon, can solve problems such as environmental pollution, complex components, and large sludge output, and achieve the effects of simple preparation, improved adsorption performance, and low cost

Inactive Publication Date: 2012-10-03
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] In recent years, with the development of urban sewage treatment industry, the output of urban sludge has increased sharply. The sludge output is large and its composition is complex. If it is not properly treated, it will cause serious environmental pollution.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] 1) Dry the sludge until the moisture content is below 10%, grind and sieve, and retain the sludge particles with a particle size range of 20-100 mesh;

[0015] 2) The sludge particles are heated up to 400°C for 60 minutes at a heating rate of 10°C / min and carbonized for 60 minutes. Nitrogen is used as the protective gas during the carbonization process;

[0016] 3) Mix the carbonized sample with 4mol / l zinc chloride solution at a mass ratio of 1:2, soak at room temperature for 12 hours, and then dry to constant weight to obtain an activated sample;

[0017] 4) The activated sample was heated to 450°C at a heating rate of 10°C / min, and after pyrolysis and activation for 90 minutes, it was cooled in nitrogen, then washed with hydrochloric acid and distilled water at 70°C, and dried to obtain sludge activated carbon;

[0018] The specific surface area of ​​sludge activated carbon is 425m 2 / g, the yield was 37.02%.

Embodiment 2

[0020] 1) Dry the sludge until the moisture content is below 10%, grind and sieve, and retain the sludge particles with a particle size range of 20-100 mesh or less;

[0021] 2) The sludge particles were heated to 450°C for 90 minutes at a heating rate of 15°C / min and carbonized for 90 minutes. Nitrogen was used as the protective gas during the carbonization process;

[0022] 3) After mixing the carbonized sample with 3mol / l zinc chloride solution at a mass ratio of 1:3, immerse at room temperature for 24 hours, and then dry to constant weight to obtain activated sludge particles;

[0023] 3) The activated sludge particles are heated up to 500°C at a heating rate of 15°C / min, and after pyrolysis and activation for 30 minutes, they are cooled in nitrogen, then washed with hydrochloric acid and distilled water at 80°C, and dried to obtain sludge activated carbon. ;

[0024] The specific surface area of ​​sludge activated carbon is 485m 2 / g, the yield was 40.12%.

Embodiment 3

[0026] 1) Dry the sludge until the moisture content is below 10%, grind and sieve, and retain the sludge particles with a particle size range of 20-100 mesh or less;

[0027] 2) The sludge particles are heated up to 500°C for 30 minutes at a heating rate of 20°C / min and carbonized for 30 minutes. Nitrogen is used as the protective gas during the carbonization process;

[0028] 3) Mix the carbonized sample with 2mol / l zinc chloride solution at a mass ratio of 1:1, soak at room temperature for 24 hours, and then dry to constant weight to obtain an activated sample;

[0029] 4) The activated sample was heated to 550°C at a heating rate of 20°C / min, and after pyrolysis and activation for 60 minutes, it was cooled in nitrogen, then washed with hydrochloric acid and distilled water at 75°C, and dried to obtain sludge activated carbon;

[0030] The specific surface area of ​​sludge activated carbon is 470.64m 2 / g, the yield is 37.26%.

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Abstract

The invention provides a method for preparing active carbon from municipal sludge by two-step thermal decomposition, belonging to the technical field of active carbon. The method comprises the following steps of: thermally decomposing and carbonizing dried municipal sludge for 30-90 minutes at 400-550 DEG C, and then adding an activator in an amount of 2-4mol / l into the carbonized sample, impregnating and activating, and then thermally decomposing and activating at high temperature of 450-600 DEG C to obtain the sludge-activated carbon. According to the method provided by the invention, the sludge is carbonized and activated by the two-step thermal decomposition and then the carbonized sludge is activated by the activator, so that the demand of the activator is greatly decreased and a way of recycling the sludge is provided to realize harmless, reduction and reclamation of the waste treatment.

Description

technical field [0001] The invention relates to a method for preparing sludge activated carbon using residual sludge from urban sewage treatment plants as the main raw material, which is suitable for the removal of various toxic gases and COD and colored substances in sewage, and belongs to the technical field of activated carbon. Background technique [0002] In recent years, with the development of urban sewage treatment industry, the output of urban sludge has increased sharply. The sludge output is large and its composition is complex. If it is not properly treated, it will cause serious environmental pollution. The treatment and disposal of sludge is an urgent problem to be solved, and the utilization of sludge as a resource has attracted more and more attention. Researchers at home and abroad have used the characteristics of a large amount of organic matter in sludge to prepare sludge into carbon-containing adsorbents. At present, the methods of preparing activated ca...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/12C01B32/324C01B32/342C01B32/348
Inventor 李依丽李利平尹晶
Owner BEIJING UNIV OF TECH
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