Iron and nitrogen treated sorbent and method for making same

Patent metadata

Field	Value
Publication number	US-12064745-B2
Application number	US-202117446501-A
Country	US
Kind code	B2
Filing date	Aug 31, 2021
Priority date	Aug 31, 2020
Publication date	Aug 20, 2024
Grant date	Aug 20, 2024

Abstract

Carbonaceous material that is activated to form precursor activated carbon is further enhanced by doping with iron and nitrogen and calcining. The resultant sorbent material has excellent catalytic properties which are useful in the field of fluid purification. The further enhancement can be performed in a single stage process or a dual stage process. The carbonaceous material includes those obtained from coal, wood, or coconut shells. The described treatment processes result in a sorbent material that has excellent performance in removing chloramine and similar compounds from fluids such as water that is intended for drinking.

First claim

The invention claimed is:

1. A sorbent material formed from a carbonaceous material comprising coconut that is activated to form a precursor activated carbon, the sorbent material comprising:
at least about 1.3 wt. % nitrogen as measured on a dry precursor activated carbon basis;
at least about 1,000 mg/kg of iron as measured on a dry precursor activated carbon basis; and
wherein the sorbent material has a volumetric chloramine removal amount of about 85 mg/mL or more when measured with a stream of water that contacts the sorbent material.

2. The sorbent material of claim 1 wherein the sorbent material has volumetric chloramine removal performance of about 70 mg/mL to about 350 mg/mL when measured with a stream of water containing chloramine that contacts a volume of the sorbent material.

3. The sorbent material of claim 1 , wherein the amount of nitrogen is about 1.3 wt. % to about 3.0 wt. %.

4. The sorbent material of claim 1 wherein the sorbent material has a peroxide destruction number of about 2.5 minutes to about 45 minutes.

5. The sorbent material of claim 1 , wherein the sorbent material has a chloramine destruction number (CDN) is at least about 25.

6. The sorbent material of claim 5 , wherein the CDN is about 25 to about 125.

7. The sorbent material of claim 1 , wherein the peroxide number is less than about 25 minutes.

8. The sorbent material of claim 7 , wherein the sorbent material has a peroxide number is about 3 minutes to about 10 minutes.

9. The sorbent material of claim 1 wherein:
the sorbent material contains at least about 0.110 mL/g of micropores, with each micropore having a pore diameter of about 0.36 nm to about 0.46 nm; and
the sorbent material has a volumetric chloroform removal performance of about 0.25 mg/mL or more when measured with a stream of water containing chloroform that contacts a volume of the sorbent material.

10. The sorbent material of claim 9 , wherein the sorbent material has a volumetric chloroform removal amount of about 0.25 mg/mL to about 0.90 mg/mL.

11. A method of manufacturing the sorbent material of claim 1 , the method comprising:
providing a carbonaceous material;
activating the carbonaceous material to form a precursor activated carbon;
optionally oxidizing the precursor activated carbon;
doping the precursor activated carbon by contacting the precursor activated carbon with an iron source and a nitrogen source to thereby form a doped precursor activated carbon;
calcining the doped precursor activated carbon by heating to a temperature of at least about 400° C. in a calcining atmosphere that does not cause any substantial oxidation or activation of the doped precursor activated carbon to thereby form a sorbent material.

12. The method of claim 11 , wherein doping the precursor activated carbon is performed in a two stage process, the two stage process including separate steps of contacting the precursor activated carbon with an iron source and contacting the precursor activated carbon with a nitrogen source.

13. The method of claim 11 , wherein contacting the precursor activated carbon with an iron source and contacting the precursor activated carbon with a nitrogen source are each performed with separate aqueous solutions.

14. The method of claim 12 , wherein the precursor activated carbon is dried after it is contacted with each aqueous solution containing the iron source and the nitrogen source.

15. The method of claim 11 , wherein:
the iron source is one or more of iron(III) chloride hexahydrate (FeCl 3 ·6H 2 O), iron(II) chloride tetrahydrate (FeCl 2 ·4H 2 O), ammonium iron(III) sulfate dodecahydrate (NH 4 Fe(SO 4 )·12H 2 O), iron(II) sulfate heptahydrate (Fe 2 SO 4 ·7H 2 O), ammonium iron(III) oxalate trihydrate ((NH 4 ) 3 Fe(C 2 O 4 ) 3 ·3H 2 O), ammonium hexacyanoferrate(II) hydrate ((NH 4 ) 4 [Fe(CN) 6 ]·xH 2 O), ammonium iron(III) citrate ((NH 4 ) 5 [Fe(C 6 H 4 O 7 ) 2 ]), sodium ferrocyanide decahydrate (Na 4 Fe(CN) 6 ·10H 2 O), sodium ferrioxalate (Na 3 Fe(C 2 O 4 ) 3 ), potassium ferrocyanide trihydrate (K 4 [Fe(CN) 6 ]·3H 2 O), potassium ferricyanide (K 3 [Fe(CN) 6 ]), potassium ferrooxalate (K 2 [Fe(C 2 O 4 ) 2 ), or iron(II) acetate tetrahydrate (CH 3 COO) 2 Fe·4H 2 O), ferrous lactate dihydrate, ferrous lactate trihydrate, urea (CO(NH 2 ) 2 ), compounds thereof, or mixtures thereof; and
the nitrogen source has an oxidation state of −3.

16. The method of claim 15 , wherein the nitrogen source is one or more of urea or dicyandiamide.

17. The method of claim 12 , wherein calcining is performed at a temperature of about 850° C. to about 1050° C. in a N 2 atmosphere.

18. The method of claim 12 , wherein the oxidizing is required and is performed.

19. The method of claim 11 , wherein doping the precursor activated carbon is performed in a single stage process, the single stage process including a single step of contacting the precursor activated carbon with both an iron source and a nitrogen source.

20. The method of claim 19 , wherein contacting the precursor activated carbon with the iron source and the nitrogen source is performed with a single aqueous solution that contains both the iron source and the nitrogen source.

21. The method of claim 20 , wherein the precursor activated carbon is dried after it is contacted with the single aqueous solution containing the iron source and the nitrogen source.

22. The method of claim 19 , wherein the iron source is iron(III) chloride hexahydrate (FeCl 3 ·6H 2 O) and the nitrogen source is one or more of urea or dicyandiamide (DCD).

23. The method of claim 19 , wherein calcining is performed at a temperature of about 400° C. to about 1050° C. in a N 2 atmosphere.

24. The method of claim 23 , wherein calcining is performed at a temperature of about 400° C. to about 600° C. in a N 2 atmosphere.

25. The method of claim 19 , wherein calcining is performed at a temperature of about 850° C. to about 1050° C. in a N 2 atmosphere.

26. The method of claim 11 , wherein the optional oxidizing is not performed.

27. The method of claim 11 , wherein the optional oxidizing is required and is performed.

28. A method of removing chlorine, chloramine, or both chlorine and chloramine from a fluid, the method comprising:
providing a sorbent material, the sorbent material being formed from a carbonaceous material comprising coconut that is activated to form a precursor activated carbon, the sorbent material comprising at least about 1.3 wt. % nitrogen as measured on a dry precursor activated carbon basis; at least about 1,000 mg/kg of iron as measured on a dry precursor activated carbon basis; and wherein the sorbent material has a volumetric chloramine removal amount of about 85 mg/mL or more when measured with a stream of water that contacts the sorbent material, and contacting the sorbent material with a fluid.

29. The method of claim 28 , wherein the fluid is liquid water.

30. The method of claim 28 , wherein the water or the sorbent material has previously undergone a disinfecting step.

31. The sorbent material of claim 1 , wherein the amount of nitrogen is at least about 2.2 wt. %.

Assignees

• Calgon Carbon Corp
• Kuraray Co

Inventors

• Mazzoccoli Jason P
• Walker Ryan W
• Tramposch Walter G
• Takahashi Keita
• Benzaki Aya

Classifications

• B01J20/06

  comprising oxides or hydroxides of metals not provided for in group B01J20/04 · CPC title

• B01J20/3236

  containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts · CPC title

• B01J20/3204

  Inorganic carriers, supports or substrates · CPC title

• B01J20/2808

  being less than 2 nm, i.e. micropores or nanopores · CPC title

• C02F2101/16

  Nitrogen compounds, e.g. ammonia · CPC title