Processes for manufacturing particles coated with activated lignosulfonate
View Patent ↗Processes for forming a filter material that includes coating a filter particle with a coating comprising a lignosulfonate, carbonizing the coating, and activating the coating. The filter particles may include a variety of filter particles, including but not limited to fibers, granules, and screens, and be formed from a variety of materials, such as metals, metal alloys, carbon, ceramic, or glass. Also, the lignosulfonate-coated filter particles may include a large amount of mesopore and/or macropore volume when carbonized and activated. One exemplary process for forming a filter material includes diluting ammonium lignosulfonate with water, mixing the solution with milled glass fibers, removing the excess lignosulfonate solution from the fibers, drying the lignosulfonate coated glass fibers at 65° C. for 12 h, carbonizing the coated glass fibers in a furnace ramped to 70° C. with a rate of 7° C./min for 30 min in a flowing nitrogen atmosphere, and activating the carbonized coated glass fibers in a furnace at 750° C. for 6 h in a flowing nitrogen/steam atmosphere.
1. A process for forming a filter material, comprising the steps of:
a) applying an aqueous lignosulfonate coating onto a filter particle;
b) carbonizing said coating; and
c) activating said coating.
2. The process of claim 1 , wherein said lignosulfonate is selected from the group consisting of ammonium lignosulfonate, zinc lignosulfonate, calcium lignosulfonate, ferric lignosulfonate, magnesium lignosulfonate, chromium lignosulfonate, manganese lignosulfonate, copper lignosulfonate, and mixtures thereof.
3. The process of claim 1 , wherein said filter particle comprises a glass fiber.
4. The process of claim 1 , wherein said filter material comprises a screen, a ceramic fiber, a woven, a non-woven, or mixtures thereof.
5. The process of claim 1 , further comprising the step of drying said coating.
6. The process of claim 1 , wherein the coating add-on before carbonization is between about 0.5% and about 97%.
7. The process of claim 1 , wherein the carbon add-on in the carbonized coating is between about 0.2% and about 95%.
8. The process of claim 1 , wherein the carbon add-on in the activated coating is between about 0.1% and about 85%.
9. The process of claim 1 , wherein the temperature during said step of carbonization is between 600° C. and about 900° C.
10. The process of claim 1 , wherein the temperature during said step of activation is between about 550° C. and about 1300° C.
11. The process of claim 1 , wherein the BET surface area of said filter particle after the activation step is between about 500 m 2 /g and about 3000 m 2 /g.
12. The process of claim 1 , wherein the suni of mesopore and macropore volumes of said filter particle is between about 0.2 mL/g and about 2.2 mL/g.
13. The process of claim 1 , wherein the ratio of the sum of mesopore and macropore volumes to micropore volume is between about 0.3 and about 3.
14. A process for forming a filter material, consisting of:
a) coating a filter particle with a lignosulfonate;
b) drying said coating;
c) carbonizing the coating at a temperature from 600° C. to about 900° C.; and
d) activating the coating.
15. The process according to claim 14 , wherein the lignosulfonate is selected from the group consisting of ammonium lignosulfonate, zinc lignosulfonate, calcium lignosulfonate, ferric lignosulfonate, magnesium lignosulfonate, chromium lignosulfonate, manganese lignosulfonate, copper lignosulfonate, and mixtures thereof.
16. The process according to claim 14 , wherein the step of carbonizing the coating is at a temperature from about 630° C. to about 800° C.
17. A process for forming a filter material, comprising:
a) forming an aqueous lignosulfonate solution;
b) mixing the aqueous lignosulfonate solution with filter particles to form aqueous lignosulfonate-coated filter particles;
c) drying the aqueous lignosulfonate-coated filter particles;
d) carbonizing the aqueous lignosulfonate-coated filter particles in a furnace at a temperature from 600° C. to about 900° C.; and
e) activating the carbonized, aqueous lignosulfonate-coated filter particles in a furnace.