Activated carbon monoliths and methods of making them

Abstract

Resol beads are disclosed that are prepared in high yield by reaction of a phenol with an aldehyde, with a base as catalyst, in the presence of a colloidal stabilizer, and optionally a surfactant. The resol beads have a variety of uses and may be carbonized and activated to form activated carbon monoliths.

Description

Claims

1. A process for producing an activated carbon monolith, the process comprising: reacting a phenol with an aldehyde in an agitated aqueous medium provided with a base as catalyst, a colloidal stabilizer, optionally a surfactant, and previously-formed resol beads, for a period of time and at a temperature sufficient to produce an aqueous dispersion of resol beads;optionally compacting the aqueous dispersion of resol beads; andcarbonizing and activating the resol beads to obtain an activated carbon monolith.

2. The process according to claim 1, wherein the activated carbon monolith has a diameter that is at least 10,000 times the median particle size of the resol beads in the aqueous dispersion.

3. The process according to claim 1, wherein the activated carbon monolith has a diameter that is at least 1,000 times the median particle size of the resol beads in the aqueous dispersion.

4. The process according to claim 1, wherein the activated carbon monolith has a diameter that is from at least 1,000 times the median particle size of the resol beads in the aqueous dispersion.

5. The process according to claim 1, further comprising grinding the activated carbon monolith to obtain monolith particles having a median particle size from about 10 times to about 10,000 times the median particle size of the resol beads of the aqueous dispersion.

6. The process according to claim 1, further comprising grinding the activated carbon monolith to obtain monolith particles having a median particle size from about 100 times to about 1,000 times the median particle size of the resol beads of the aqueous dispersion.

7. The process according to claim 1, wherein the carbonizing and activating are accomplished in separate steps.

8. The process according to claim 1, wherein the carbonizing and activating are accomplished in a single step in the same gaseous atmosphere.

9. The process according to claim 1, wherein the previously-formed resol beads have a median particle size from about 10 μm to about 1,500 μm.

10. The process according to claim 1, wherein the previously-formed resol beads have a median sphericity value from about 0.90 to 1.0.

11. The process according to claim 1, wherein the previously-formed resol beads have a median particle size from 50 μm to 1,000 μm.

12. The process according to claim 1, wherein the previously-formed resol beads have a median particle size from 75 μm to 750 μm.

13. The process according to claim 1, wherein the previously-formed resol beads have a median particle size from about 125 μm to about 300 μm.

14. The process according to claim 1, wherein the previously-formed resol beads have a particle size distribution span from about 10 to about 500.

15. The process according to claim 1, wherein the previously-formed resol beads have a particle size distribution span from about 25 to about 250.

16. The process according to claim 1, wherein the previously-formed resol beads have a particle size distribution span from about 25 to about 150.

17. The process according to claim 1, wherein the resol beads obtained have a median particle size from about 10 μm to about 2,000 μm.

18. The process according to claim 1, wherein the resol beads obtained have a median sphericity value from about 0.90 to 1.0.

19. The process according to claim 1, wherein the resol beads obtained have a median particle size from about 100 μm to about 750 μm.

20. The process according to claim 1, wherein the carbonizing and activating are accomplished at a temperature from about 500° C. to about 1,500° C.

21. The process according to claim 1, wherein the phenol comprises monohydroxybenzene.

22. The process according to claim 1, wherein the aldehyde comprises formaldehyde.

23. The process according to claim 1, wherein the base comprises one or more of ammonia or ammonium hydroxide.

24. The process according to claim 1, wherein the previously-formed resol beads are provided in an amount of at least 10 wt. %, based on the weight of the phenol.

25. The process according to claim 1, wherein the molar ratio of the aldehyde to the phenol is from about 1.1:1 to about 3:1.

26. The process according to claim 1, wherein the colloidal stabilizer comprises a carboxymethyl cellulose salt.

27. The process according to claim 26, wherein the carboxymethyl cellulose salt has a degree of substitution from about 0.6 to about 1.1 and a weight average molecular weight from about 100,000 to about 400,000.

28. The process according to claim 1, wherein the total external surface area of the previously-formed resol beads is at least 4 m2 per each kilogram of phenol.

29. The process according to claim 1, wherein the temperature is from 75° C. to 90° C.

30. The process according to claim 1, wherein the surfactant is present and comprises an anionic surfactant.

31. The process according to claim 1, wherein the surfactant is present and comprises one or more of: sodium dodecyl sulfate or sodium dodecyl benzene sulfonate.

32. The process according to claim 1, wherein the base comprises one or more of: ammonia or hexamethylenetetramine.

33. The process according to claim 1, wherein methanol is present in the aldehyde provided to the reaction mixture in an amount of no more than about 2 wt. %, based on the total weight of the aldehyde.

34. The process according to claim 1, wherein the agitated aqueous medium is agitated by one or more of: a pitched blade impeller; a high efficiency impeller; a turbine; an anchor; a spiral agitator; a rotating agitator; flow induced by circulation; or flowing the aqueous medium past one or more stationary mixing devices.

35. A process for producing an activated carbon monolith, the process comprising: providing to an agitated aqueous reaction mixture a phenol, a portion of an aldehyde, a portion of a base as catalyst, a colloidal stabilizer, optionally a surfactant, and previously-formed resol beads;reacting in the reaction mixture for a period of time and at a temperature sufficient to produce an aqueous dispersion of partially-formed resol beads;thereafter adding a remaining portion of the aldehyde and a remaining portion of the base to obtain a resol monolith;optionally compacting the resol monolith; andcarbonizing and activating the resol monolith to obtain an activated carbon monolith.

36. A process for producing an activated carbon monolith, the process comprising: providing a portion of a phenol, a portion of an aldehyde, and a portion of a base as catalyst to a reaction mixture which is an agitated aqueous medium that includes a colloidal stabilizer, optionally a surfactant, and previously-formed resol beads;reacting for a period of time and at a temperature sufficient to produce an aqueous dispersion of partially-formed resol beads;thereafter providing a further portion of the phenol, a further portion of the aldehyde, and a further portion of the base to the reaction mixture and reacting for a further period of time;thereafter adding any remaining portion of the phenol, the aldehyde, and the base over a period of time and at a temperature sufficient to obtain a resol monolith;optionally compacting the resol monolith; andcarbonizing and activating the resol monolith to obtain an activated carbon monolith.

37. The process according to claim 36, wherein at least a quarter of the total charge of formaldehyde and ammonia is charged to the reactor and the remainder is charged in semi-batch mode.

38. The process according to claim 36, wherein the aldehyde and the base are added to the reaction mixture over a period from about 15 minutes to about 180 minutes.

39. The process according to claim 36, wherein the addition of formaldehyde and ammonia to the reaction mixture begins from about 5 minutes to about 180 minutes after the initial of reactants to the reactor.

40. An activated carbon monolith made by a process comprising: reacting a phenol with an aldehyde in an agitated aqueous medium provided with a base as catalyst, a colloidal stabilizer, optionally a surfactant, and previously-formed resol beads, for a period of time and at a temperature sufficient to produce an aqueous dispersion of resol beads;optionally compacting the aqueous dispersion of resol beads; andcarbonizing and activating the resol beads to obtain an activated carbon monolith.

41. The process according to claim 40, wherein the activated carbon monolith has a diameter that is at least 10,000 times the median particle size of the resol beads in the aqueous dispersion.

42. The process according to claim 40, wherein the activated carbon monolith has a diameter that is at least 1,000 times the median particle size of the resol beads in the aqueous dispersion.

43. The process according to claim 40, wherein the activated carbon monolith has a diameter that is from at least 1,000 times the median particle size of the resol beads in the aqueous dispersion.

44. The process according to claim 40, further comprising grinding the activated carbon monolith to obtain monolith particles having a median particle size from about 10 times to about 10,000 times the median particle size of the resol beads of the aqueous dispersion.

45. The process according to claim 40, further comprising grinding the activated carbon monolith to obtain monolith particles having a median particle size from about 100 times to about 1,000 times the median particle size of the resol beads of the aqueous dispersion.

46. The activated carbon monolith according to claim 40, wherein the carbonizing and activating are accomplished in separate steps.

47. The activated carbon monolith according to claim 40, wherein the carbonizing and activating are accomplished in the same gaseous atmosphere.

48. The activated carbon monolith according to claim 40, wherein the previously-formed resol beads have a median particle size from about 10 μm to about 1,500 μm.

49. The activated carbon monolith according to claim 40, wherein the previously-formed resol beads have a median sphericity value from about 0.90 to 1.0.

50. The activated carbon monolith according to claim 40, wherein the previously-formed resol beads have a median particle size from 75 μm to 750 μm.

51. The activated carbon monolith according to claim 40, wherein the previously-formed resol beads have a median particle size from about 125 μm to about 300 μm.

52. The activated carbon monolith according to claim 40, wherein the previously-formed resol beads have a particle size distribution span from about 10 to about 500.

53. The activated carbon monolith according to claim 40, wherein the previously-formed resol beads have a particle size distribution span from about 25 to about 250.

54. The activated carbon monolith according to claim 40, wherein the previously-formed resol beads have a particle size distribution span from about 25 to about 150.

55. The activated carbon monolith according to claim 40, wherein the resol beads obtained have a median particle size from about 10 μm to about 2,000 μm.

56. The activated carbon monolith according to claim 40, wherein the resol beads obtained have a median sphericity value from about 0.90 to 1.0.

57. The activated carbon monolith according to claim 40, wherein the resol beads obtained have a median particle size from about 100 μm to about 750 μm.

58. The activated carbon monolith according to claim 40, wherein the carbonizing and activating are accomplished at a temperature from about 500° C. to about 1,500° C.

59. The activated carbon monolith according to claim 40, wherein the phenol comprises monohydroxybenzene.

60. The activated carbon monolith according to claim 40, wherein the aldehyde comprises formaldehyde.

61. The activated carbon monolith according to claim 40, wherein the base comprises one or more of ammonia or ammonium hydroxide.

62. The activated carbon monolith according to claim 40, wherein the previously-formed resol beads are provided in an amount of at least 10 wt. %, based on the weight of the phenol.

63. The activated carbon monolith according to claim 40, wherein the molar ratio of the aldehyde to the phenol is from about 1.1:1 to about 3:1.

64. The activated carbon monolith according to claim 40, wherein the colloidal stabilizer comprises a carboxymethyl cellulose salt.

65. The activated carbon monolith according to claim 64, wherein the carboxymethyl cellulose salt has a degree of substitution from about 0.6 to about 1.1 and a weight average molecular weight from about 100,000 to about 400,000.

66. The activated carbon monolith according to claim 40, wherein the total external surface area of the previously-formed resol beads is at least 4 m2 per each kilogram of phenol.

67. The activated carbon monolith according to claim 40, wherein the temperature is from 75° C. to 90° C.

68. The activated carbon monolith according to claim 40, wherein the surfactant is present and comprises an anionic surfactant.

69. The activated carbon monolith according to claim 40, wherein the surfactant is present and comprises one or more of: sodium dodecyl sulfate or sodium dodecyl benzene sulfonate.

70. The activated carbon monolith according to claim 40, wherein the base comprises one or more of: ammonia or hexamethylenetetramine.

71. The activated carbon monolith according to claim 40, wherein methanol is present in the aldehyde provided to the reaction mixture in an amount of no more than about 2 wt. %, based on the total weight of the aldehyde.

72. The activated carbon monolith according to claim 40, wherein the agitated aqueous medium is agitated by one or more of: a pitched blade impeller; a high efficiency impeller; a turbine; an anchor; a spiral agitator; a rotating agitator; flow induced by circulation; or flowing the aqueous medium past one or more stationary mixing devices.

73. An activated carbon monolith made by a process comprising: providing to an agitated aqueous reaction mixture a phenol, a portion of an aldehyde, a portion of a base as catalyst, a colloidal stabilizer, optionally a surfactant, and previously-formed resol beads;reacting in the reaction mixture for a period of time and at a temperature sufficient to produce an aqueous dispersion of partially-formed resol beads;thereafter adding a remaining portion of the aldehyde and a remaining portion of the base to obtain a resol monolith;optionally compacting the resol monolith; andcarbonizing and activating the resol monolith to obtain an activated carbon monolith.

74. An activated carbon monolith made by a process comprising: providing a portion of a phenol, a portion of an aldehyde, and a portion of a base as catalyst to a reaction mixture which is an agitated aqueous medium that includes a colloidal stabilizer, optionally a surfactant, and previously-formed resol beads;reacting for a period of time and at a temperature sufficient to produce an aqueous dispersion of partially-formed resol beads;thereafter providing a further portion of the phenol, a further portion of the aldehyde, and a further portion of the base to the reaction mixture and reacting for a further period of time;thereafter adding any remaining portion of the phenol, the aldehyde, and the base over a period of time and at a temperature sufficient to obtain a resol monolith;optionally compacting the resol monolith; andcarbonizing and activating the resol monolith to obtain an activated carbon monolith.

75. The activated carbon monolith according to claim 74, wherein at least a quarter of the total charge of formaldehyde and ammonia is charged to the reactor and the remainder is charged in semi-batch mode.

76. The activated carbon monolith according to claim 74, wherein the aldehyde and the base are added to the reaction mixture over a period from about 15 minutes to about 180 minutes.

77. The activated carbon monolith according to claim 74, wherein the addition of formaldehyde and ammonia to the reaction mixture begins from about 5 minutes to about 180 minutes after the initial of reactants to the reactor.