Activated carbon with a high adsorption capacity and a low residual phosphoric acid content, a process for its preparation, and applications of it

• US 20020172637A1
• Filed: 03/01/2002
• Published: 11/21/2002
• Est. Priority Date: 03/01/2001
• Status: Abandoned Application

• Current Assignee: PICA
• Original Assignee: PICA
• Inventors: Pilard, Myriam, Dagois, Gerard, Flasseur, Anne, Chesneau, Manuel
• Application Number:
  US10/085,126
• Publication Number:
  US 20020172637A1
• Time in Patent Office: Days
• US Class Current: 423/445R
• CPC Class Codes: C01B 32/342 characterised by non-gaseous activating agents
• CPC Class Codes: C02F 1/283 using coal, charred products, or inorganic mixtures containing them
• CPC Class Codes: C02F 2101/306 Pesticides
• CPC Class Codes: C02F 2103/007 Contaminated open waterways, rivers, lakes or ponds

Abstract

An activated carbon is disclosed having the following characteristics:

CCl₄ number from 120% to 190%,

P₂O₅ content at most equal to 2%,

extraction pH greater than 7,

bulk density from 0.18 g/ml to 0.32 g/ml, and

electrical resistivity less than 1.5 ohm.cm.

Claims

1. Activated carbon having the following characteristics:

CCl₄ number from 120% to 190%,

P₂O₅ content at most equal to 2%,

extraction pH greater than 7,

bulk density from 0.18 g/ml to 0.32 g/ml, and

electrical resistivity less than 1.5 ohm.cm.

2. The activated carbon claimed in claim 1 when it has a BET surface area of at least 2 000 m²/g.

3. The activated carbon claimed in claim 1 when it has a BET surface area of at least 1 800 m²/g.

4. The activated carbon claimed in claim 1 when it has an iodine number of at least 1 750 mg/g.

5. The activated carbon claimed in claim 1 when it has a butane adsorption coefficient of 45% to 75%.

6. The activated carbon claimed in claim 1 when it has a ball-pan hardness of at least 65%.

7. The activated carbon claimed in claim 1 when it has a particle size distribution in which the particle size is less than 4.75 mm and greater than 0.15 mm.

8. The activated carbon claimed in claim 1 when it is a powder with a particle size less than 212 microns.

9. The activated carbon claimed in claim 1 when it has a micropore volume of at least 0.50 ml/g and a mesopore volume of at least 0.30 ml/g.

21. Use of activated carbon as claimed in any of claims 1 to 9 for the treatment of water containing organic matter.

22. Use of activated carbon as claimed in any of claims 1 to 9 to remove atrazine.

23. Use of activated carbon as claimed in any of claims 1 to 9 to remove chloramines.

10. A process for manufacturing an activated carbon, said process comprising the following stages:

preparing a precursor activated carbon by chemically activating a starting material with phosphoric acid,

neutralizing said precursor with an aqueous solution, and

thermal activation.

11. The process claimed in claim 10 wherein said precursor is obtained by chemically activating wood with phosphoric acid.

12. The process claimed in claim 10 wherein said precursor has the following characteristics:

CCl₄ number from 60% to 120%,

P₂O₅ content from 3% to 12%,

extraction pH from 1 to 2,

bulk density from 0.18 g/ml to 0.32 g/ml, and

electrical resistivity greater than 500 ohm.cm.

13. The process claimed in claim 12 wherein said precursor additionally has the following characteristics:

butane adsorption coefficient 22% to 47%,

iodine number at least 900 mg/g,

BET surface area at least 900 m²/g, and

ball-pan hardness from 50% to 65%.

14. The process claimed in claim 10 wherein said neutralization is carried out with urea or ammonia.

15. The process claimed in claim 10 wherein the base/precursor ratio is from 0.1 to 0.3.

16. The process claimed in claim 10 wherein the water/precursor ratio is from 1.5 to 2.5.

17. The process claimed in claim 10 wherein said neutralization includes drying in order to reduce the water content of said product to less than 10%.

18. The process claimed in claim 10 wherein said activation is carried out at a reaction temperature from 800°

C. to 1 000°

C.

19. The process claimed in claim 10 wherein said activation is carried out in a furnace in the presence of steam and/or carbon dioxide.

20. The process claimed in claim 10 wherein said precursor has a particle size greater than the ASTM No. 70 sieve (212 microns) and further including a particle size grading stage.