초록 ▼

A method of removing arsenic and heavy metals from water using metal salt hydroxidegels is provided. The arsenic present in water is adsorbed onto the hydroxide-gels which can effectively be filtered through a diatomaceous earth (DE) filtration bed. The combination of DE mixed hydroxide-gels is also

A method of removing arsenic and heavy metals from water using metal salt hydroxidegels is provided. The arsenic present in water is adsorbed onto the hydroxide-gels which can effectively be filtered through a diatomaceous earth (DE) filtration bed. The combination of DE mixed hydroxide-gels is also effective in removing arsenic from water and heavy metals from water.

대표청구항 ▼

We claim: 1. A method of removing arsenic from arsenic-containing water comprising: coating diatomaceous earth with one or more metal salt hydroxide-gels to form diatomaceous earth pre-coated hydroxide-gels, wherein said metal salt is selected from the group consisting of lanthanum salt, ferric sal

We claim: 1. A method of removing arsenic from arsenic-containing water comprising: coating diatomaceous earth with one or more metal salt hydroxide-gels to form diatomaceous earth pre-coated hydroxide-gels, wherein said metal salt is selected from the group consisting of lanthanum salt, ferric salt, and aluminum salt; contacting said arsenic-containing water with said diatomaceous earth pre-coated hydroxide-gels; and filtering said water through a diatomaceous earth filter bed or a diatomaceous earth-precoat filter. 2. The method of claim 1, wherein said said filtering uses a filter screen or septum made of water-compatible material coated with diatomaceous earth. 3. The method of claim 2, wherein said water-compatible material is polyethylene, polypropylene or stainless steel. 4. The method of claim 1, wherein said filter is a diatomaceous earth filter bed. 5. The method of claim 1, wherein said metal salt hydroxide-gel is formed by adjusting the pH of a solution containing metal salts so that a metal salt hydroxide-gel is formed. 6. The method of claim 1, wherein diatomaceous earth pre-coated hydroxide-gels are contacted with said arsenic-containing water at a pH from about 2 to about 14. 7. The method of claim 1 wherein said contacting step is performed using a member of the group consisting of: mechanical mixing, ultrasonic mixing, mixing in-line using an atomizer, mixing in-line using venturi and mixing using metering pumps. 8. The method of claims 1, wherein said metal salt hydroxide-gel is formed from at least one member of the group consisting of: lanthanum chloride, lanthanum nitrate, lanthanum carbonate, ferric chloride, ferric sulfate, aluminum chloride, aluminum nitrate, aluminum sulfate, and sodium aluminate. 9. The method of claim 8, wherein said metal salt comprises more than one metal salt. 10. The method of claim 1, wherein said arsenic-containing water contains arsenic at a concentration of about 10 ppb to 100 ppm. 11. The method of claim 10, wherein said arsenic-containing water contains one or more members selected from the group consisting of: arsenite and arsenate. 12. The method of claim 10, wherein said arsenic-containing water comprises one or more members of the group selected from: raw water, well water, drinking water, and process water. 13. The method of claim 1, wherein said precoated hydroxide-gels are contacted with said arsenic-containing water for a time of between about 1 minute to about 6 minutes at a pH between about 3 and about 12. 14. The method of claim 1, wherein said metal salt hydroxide-gel comprises lanthanum and ferric hydroxides. 15. The method of claim 1, wherein metal salt hydroxide-gels comprise weight ratios of between about 1:1 and 1:10 of lanthanum: ferric hydroxides. 16. The method of claim 1, wherein said metal salt hydroxide-gel consists essentially of lanthanum hydroxide. 17. The method of claim 1, wherein said metal salt hydroxide-gel comprises a lanthanum hydroxide.