Treatment of arsenic contaminated soil and water
View Patent ↗The present invention is directed to a method for the treatment of an environmental medium contaminated with arsenic, comprising treating such medium with an effective amount of persulfate and zero valent iron.
1. A method for the treatment of an environmental medium contaminated with arsenic, comprising treating such medium with an effective amount of persulfate and zero valent iron, and a precipitation additive, wherein the precipitation additive is selected from the group consisting of phosphates salts, calcium hydroxide, calcium oxide, sodium hydroxide, sodium carbonate, calcium carbonate and mixtures thereof.
2. The method of claim 1 , wherein the environmental medium is selected from soil, groundwater, process water or wastewater.
3. The method of claim 1 , wherein the persulfate is a dipersulfate.
4. The method of claim 3 , wherein the dipersulfate is selected from sodium, potassium or ammonium persulfate or a combination thereof.
5. The method of claim 1 , wherein the persulfate is a monopersulfate.
6. The method of claim 5 , wherein the monopersulfate is selected from sodium and potassium monopersulfate.
7. The method of claim 1 , wherein the persulfate is a combination of a dipersulfate and monopersulfate.
8. The method of claim 1 wherein the zero valent iron has a nanoscale particle size of from 10 nanometers to 1 micron.
9. The method of claim 1 wherein the zero valent iron has a micro scale particle size of from 1 micron to 300 microns.
10. The method of claim 1 wherein the environmental medium is water and the concentration of the persulfate is from 0.5 mg/L to 250,000 mg/L of water.
11. The method of claim 1 wherein the environmental medium is soil and the concentration of the persulfate is from 0.5 g/kg to 50 g/kg of soil.
12. The method of claim 1 wherein the treatment is performed in situ or ex situ.
13. The method of claim 1 wherein the zero valent iron is suspended if in a solution comprising sodium persulfate.
14. The method of claim 1 wherein the zero valent iron and sodium persulfate are added as solids.
15. The method of claim 1 wherein the weight ratio of persulfate to zero valent iron is between 1:1 and 1:20.
16. The method of claim 15 wherein the weight ratio of persulfate to zero valent iron is between 1:5 and 1:15.