Rice husk filter media, and methods

Abstract

The inventive subject matter disclosed herein includes multiple novel filter media made of activated rice husks, as well as filtration systems and methods for removing contaminants from an aqueous solution, such as wastewater produced as a byproduct of various industrial processes, including mining, oil and gas exploration and extraction, farming, manufacturing, and the like.

We claim: 
     
         1 .- 16 . (canceled) 
     
     
         17 . A media for removal of a plurality of heavy metals from a solution,
 wherein the media has an adsorption capacity and an ion exchange capacity for the plurality of heavy metals in the solution comprising: a microporous mesh consistently essentially of fibers comprised of an at least partially charred intact rice husks not having a silicon content greater than 40 percent.   
     
     
         18 . The media of  claim 17 , wherein one of the heavy metals is copper and the ion exchange capacity of the media is 0.31 mEq/g and the adsorption capacity of 10 mg/g for the copper. 
     
     
         19 . The media of  claim 17 , wherein one of the heavy metals is zinc and the ion exchange capacity of the media is 0.12 mEq/g and the adsorption capacity of 4 mg/g for zinc. 
     
     
         20 . The media of  claim 17 , wherein one of the heavy metals is nickel and the ion exchange capacity of the media is 0.41 mEq/g and the adsorption capacity of 12 mg/g for the nickel. 
     
     
         21 . The media of  claim 17 , wherein one of the heavy metals is lead and the ion exchange capacity of the media is 0.10 mEq/g and the adsorption capacity of 7 mg/g for the lead. 
     
     
         22 . The media of  claim 17 , wherein one of the heavy metals is chromium and the ion exchange capacity of the media is 0.29 mEq/g and the adsorption capacity of 5 mg/g for the chromium. 
     
     
         23 . The media of  claim 17  further comprising fibers of between 0.1 and 2 mm in length, wherein said microporous mesh has a porosity of between 0.4 -0.55 and a specific surface area of between 400-500 m 2 /g. 
     
     
         24 . The media of  claim 23 , wherein a media capacity of the microporous mesh is about 4000 grains of the heavy metal per cubic foot of media. 
     
     
         25 . The media of  claim 24 , wherein the media capacity of the microporous mesh is between 4206-4314 grains of copper of copper per cubic foot of media. 
     
     
         26 . The media of  claim 24 , wherein the media capacity of said media is between 3797-4033 grains of chromium per cubic foot of media. 
     
     
         27 . The media of  claim 23 , wherein a silt density index of the media is about 50 μm 
     
     
         28 . The media of  claim 23 , wherein a surface charge density of the media is 0.01 Coulombs/cm 2    
     
     
         29 . The media of  claim 23 , wherein one of the heavy metals is copper and the ion exchange capacity of the media is 0.4 mEq/g and the adsorption capacity of 13 mg/g for the copper. 
     
     
         30 . The media of  claim 23 , wherein one of the heavy metals is zinc and an ion exchange capacity of the media is 0.12 mEq/g and the adsorption capacity of 5.4 mg/g for the zinc. 
     
     
         31 . The media of  claim 23 , wherein one of the heavy metals is nickel and the ion exchange capacity of the media is 0.55 mEq/g and the adsorption capacity of 16.3 mg/g mg/g for the nickel. 
     
     
         32 . The media of  claim 23 , wherein one of the heavy metals is lead and the ion exchange capacity of the media for the lead is 0.12 mEq/g and the adsorption capacity of 5.4 mg/g for the lead. 
     
     
         33 . The media of  claim 23 , wherein one of the heavy metals is chromium and the ion exchange capacity of the media is 3.22 mEq/g and the adsorption capacity is 55.8 mg/g for the chromium. 
     
     
         34 . The media of  claim 23 , wherein the ion exchange capacity of the media ranges from about 0.12 mEq/g to 3.22 mEq/g. 
     
     
         35 . A method to remove a plurality of heavy metals from a first solution by an ion exchange process comprising:
 contacting the first solution with a microporous mesh consisting essential of partially charred rice husks not having a silicon content greater than 40 percent, to bind the plurality of heavy metals to said microporous mesh; and treating said microporous mesh to release said plurality of heavy metals; and further comprising the step of: treating said microporous mesh to bind the plurality of heavy metals in a second solution containing the plurality of heavy metals.