Method for nitrogen removal and nitrogen salts recovery using carboxylated cellulose extracted by nitro-oxidation
A method of treating contaminated water, such as wastewater, with carboxylated cellulose to remove ammonium and nitrogen-containing impurities is claimed. Carboxylated cellulose extracted by nitro-oxidation has negatively-charged functionality and forms an aggregate when exposed to positively-charged impurities in contaminated water. The aggregate, nitrogen-containing impurities, and by-products from the nitro-oxidation process can be isolated to provide a fertilizer or fertilizer component.
1. A method of treating contaminated water to remove ammonium and nitrogen-containing impurities and recover ammonium salts comprising:
(1) exposing contaminated water to cellulose processed by nitro-oxidation which aggregate with positively charged ammonium ions and nitrogen containing impurities in water, to form an aggregate and treated water;
(2) separating the aggregate from the treated water; and
(3) isolating ammonium salts from the aggregate, wherein the contaminated water comprises ammonium, nitrogen-containing impurities, or combinations thereof; and
the cellulose comprises negatively charged functional groups comprising —COO − , —Cl − , —Br − , —I − , —F − , —CH 2 COO − , —SO 4 −2 , or combinations thereof.
2. A method according to claim 1 , wherein the ammonium salts are converted into ammonium sulfates, ammonium phosphates, ammonium nitrites, ammonium nitrates, ammonium hydroxide, or combinations thereof.
3. A method of making a fertilizer or a fertilizer component from contaminated water comprising:
(a) exposing contaminated water to cellulose comprising negatively charged functional groups which aggregate with positively charged ammonium ions and nitrogen containing impurities in water, to form an aggregate and treated water; and
(b) isolating the aggregate to provide a fertilizer or fertilizer component;
wherein the negatively charged functional groups comprise —COO − , —Cl − , —Br − , —I − , —F − , —CH 2 COO − , —SO 4 −2 , or combinations thereof.
4. A method according to claim 3 , wherein the aggregate is processed to isolate ammonium salts to provide a fertilizer component.
5. A method according to claim 4 , wherein the ammonium salts are converted into ammonium sulfates, ammonium phosphates, ammonium nitrites, ammonium nitrates, ammonium hydroxide, or combinations thereof.
6. A method according to claim 3 , wherein the aggregate is a slow-release fertilizer.
7. A method according to claim 1 , wherein the cellulose is extracted from a raw or untreated biomass.
8. A method according to claim 1 , wherein the cellulose is in the form of microfibers, nanofibers, or combinations thereof.
9. A method according to claim 1 , wherein the cellulose is present in a concentration of about 0.05% to about 1% based upon the weight of the contaminated water.
10. A method according to claim 1 , wherein ammonium and nitrogen-containing impurities are present in the contaminated water in about 1 to about 125 ppm.
11. A method according to claim 3 , wherein the cellulose is extracted from a raw or untreated biomass using a nitro oxidation method and wherein nitrogen and oxygen byproducts produced from the nitro-oxidation method are converted to nitrate salts and added to the fertilizer or fertilizer component provided in step (b).
12. A method according to claim 3 , wherein the cellulose is extracted from a raw or untreated biomass using a nitro-oxidation method.
13. A method according to claim 3 , wherein the cellulose is in the form of microfibers, nanofibers, or combinations thereof.
14. A method according to claim 3 , wherein the cellulose is present in a concentration of about 0.05% to about 1% based upon the weight of the contaminated water.
15. A method according to claim 3 , wherein ammonium and nitrogen-containing impurities are present in the contaminated water in about 1 to about 125 ppm.