Chromium-free impregnated activated carbon for adsorption of toxic gases and/or vapors
Abstract
Abstract Impregnated activated carbon adsorbents for the removal of toxic materials from gas streams are used in a variety of respiration and collective filter applications. The activated carbon impregnated adsorbents in the present invention remain effective in removing toxic gases and/or vapors in military, industrial and other applications, and are free of chromium and its potential health hazards. Generally, these activated carbons are comprised of an activated carbon adsorbent impregnated so as to result in an activated carbon containing 0 to 14% copper and 2 to 16% zinc, optionally supplemented according to the desired characteristics with silver, triethylenediamine, and prepared with or without the use of organic acid. The adsorbent carbons of the present invention have been found to be effective for removing a variety of toxic gases and/or vapors. The formulation of the impregnates, the method of impregnation and the method of drying the activated carbon after impregnation taught by the present invention can be varied to adjust the performance characteristics so as to meet both industrial and military toxic gas performance criteria, to achieve enhanced removal of specific toxic gases and/or vapors, to have an extended shelf like, as well as to obtain other advantages useful in respirator and collective filter applications. The impregnated carbon adsorbents in the present invention possess desirable qualities regarding the toxicity and carcinogenicity of the impregnates to the user, qualities that are not found in a large number of prior art impregnates potentially useful in respirator and collective filter applications.
Inventors
- 👤 David T. Doughty
- 👤 James E. Groose
Bibliographic Details
Claims Analysis
Total Claims: 10References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-11-04 | 1995-05-06 | 1995-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-04 | 1999-05-06 | 1999-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-04 | 2003-05-06 | 2003-11-05 | $7700.00 | Window Closed / Lapsed |