REMOVAL OF ARSENIC FROM DRINKING AND PROCESS WATER
A method of removing arsenic and heavy metals from water using metal salt hydroxide-gels 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.
1 - 20 . (canceled)
21 . A method of making a diatomaceous earth-coated hydroxide gel useable for removing arsenic from water, comprising:
in solution, contacting a precipitating composition with diatomaceous earth; and
adjusting the pH of the solution to form a diatomaceous earth-coated hydroxide-gel.
22 . The method of claim 21 , wherein the precipitating composition comprises metal salts.
23 . The method of claim 22 , wherein the metal salts comprise lanthanum chloride.
24 . The method of claim 23 , wherein the metal salts comprise an iron salt.
25 . The method of claim 24 , wherein the iron salt comprises ferric chloride.
26 . The method of claim 22 , wherein the metal salts comprise non-hydroxide metal salts.
27 . The method of claim 21 , further comprising separating the diatomaceous earth-coated hydroxide-gel from the solution.
28 . The method of claim 21 , wherein adjusting the pH of the solution comprises adjusting the pH of the solution to between pH 6 and about pH 10.