Treatment of cyanotoxin-containing water
Provided herein are methods and compositions for reducing the level of a cyanotoxin in cyanotoxin contaminated-water. The electrolytic destruction methods can include contacting the contaminated water with an electrochemical cell in the presence of a magnesium salt and applying an electrical current to the water for a time and in an amount sufficient to oxidize the cyanotoxin. The methods are useful for treatment of lake water, reservoir water, pond water, river water, or irrigation water and any water that serves as a source of drinking water.
1. A method of reducing the level of a cyanotoxin in cyanotoxin-contaminated fresh water by oxidation, wherein the water is selected from the group consisting of: lake water; reservoir water; pond water; river water; irrigation water; and drinking water; the method consisting essentially of:
a) contacting the water with an electrochemical cell in the presence of a magnesium salt that has been added to the cyanotoxin-contaminated water, wherein: i) the concentration of the magnesium salt is from about 1 ppm to about 400 ppm; and ii) selected from the group consisting of: magnesium sulfate; magnesium phosphate; magnesium carbonate; magnesium bicarbonate; and magnesium citrate: and
b) applying an electrical current to the water at a current density and for a time sufficient to reduce the levels of cyanotoxin by at least 80%;
wherein the cyanotoxin is selected from the group consisting of: microcystins, nodularins, anatoxin-a, anatoxin-a(S), cylindrospermopsins, lyngbyatoxin, saxitoxin, lipopolysaccharides, aplysiatoxins, and β-methylamino-L-alanine.
2. The method of claim 1 , wherein the microcystin is microcystin-LR, microcystin-LA, microcystin-RR, microcystin-YR or a combination thereof.
3. The method of claim 1 , wherein the cyanotoxin level in the water is from about 0.5 μg/L to about 1 g/L.
4. The method of claim 1 , wherein the electrochemical cell is an undivided cell.
5. The method of claim 4 , wherein the electrochemical cell comprises one or more boron-doped diamond electrodes.
6. The method of claim 1 , wherein the concentration of the magnesium salt is from about 1 ppm to about 300 ppm.
7. The method of claim 1 , wherein the concentration of the magnesium salt is from about 100 ppm to about 300 ppm.
8. The method of claim 1 wherein the current density is from about 0.5 mA/cm 2 to about 1000 mA/cm 2 .
9. The method of claim 4 wherein the current density is from about 0.5 mA/cm 2 to about 100 mA/cm 2 .
10. The method of claim 1 , wherein the time is from about two minutes to about 180 minutes.
11. The method of claim 1 , wherein the cyanotoxin concentration in the cyanotoxin contaminated water is from about 1 μg/L to about 200,000 μg/L.
12. The method of claim 1 wherein the current is applied at a temperature between about 1° C. to about 100° C.
13. The method of claim 1 wherein the current is applied at a temperature between about 10° C. to about 55° C.
14. The method of claim 10 , wherein the current density is from about 0.5 mA/cm 2 to about 1000 mA/cm 2 .
15. The method of claim 14 wherein the current is applied at a temperature between about 1° C. to about 100° C.
16. The method of claim 15 , wherein the electrolytic cell comprises a boron doped diamond electrode serving as an anode and a boron-doped diamond electrode serving as a cathode.
17. The method of claim 16 , wherein the cyanotoxin is a microcystin.
18. The method of claim 16 , wherein the microcystin is microcystin-LR, microcystin-LA, microcystin-RR, microcystin-YR or a combination thereof.
19. The method of claim 17 , wherein the cyanotoxin level in the water is from about 0.5 μg/L to about 1 g/L.
20. The method of claim 19 , wherein the concentration of the magnesium salt is from about 100 ppm to about 300 ppm.