Inverse Fluidization for Purifying Fluid Streams

Abstract

A method for removing a contaminant from a fluid system comprises contacting the fluid system with an inversely fluidized material, for example a particulate aerogel, thereby removing at least a portion of the contaminant from the fluid system. The method can be used to remove oil or other organic materials from wastewater streams. It can be conducted in a fluidized bed, which includes nanoporous particles and a fluidizing medium, wherein the nanoporous particles have a density lower than that of the fluidizing medium.

1 . A method for removing a contaminant from a fluid system, the method comprising contacting the fluid system with an inversely fluidized nanoporous metal oxide material, thereby removing at least a portion of the contaminant from the fluid system. 
   
   
       2 . The method of  claim 1 , wherein the fluid system is a liquid system. 
   
   
       3 . The method of  claim 2 , wherein the fluid system is wastewater. 
   
   
       4 . The method of  claim 1 , wherein the fluid system includes a supercritical fluid. 
   
   
       5 . The method of  claim 1 , wherein the contaminant is an organic material. 
   
   
       6 . The method of  claim 1 , wherein the contaminant is an oil. 
   
   
       7 . The method of  claim 1 , wherein the nanoporous metal oxide material is an aerogel. 
   
   
       8 . The method of  claim 1 , wherein the nanoporous metal oxide material is a particulate aerogel material. 
   
   
       9 . The method of  claim 8 , wherein the aerogel has a particles size larger than about 0.5 mm. 
   
   
       10 . The method of  claim 1 , wherein the nanoporous metal oxide material is hydrophobic. 
   
   
       11 . The method of  claim 1 , wherein the nanoporous metal oxide material is an oxide of a metal selected from the group consisting of silicon, aluminum, zirconium, titanium, hafnium, vanadium, yttrium and any combination thereof. 
   
   
       12 . The method of  claim 1 , wherein the method is conducted in an inverse fluidization bed. 
   
   
       13 . A purification process, wherein the process includes the method of  claim 1 . 
   
   
       14 . A fluidized bed comprising nanoporous metal oxide particles and a fluidizing medium, wherein the nanoporous metal oxide particles have a density lower than that of the fluidizing medium. 
   
   
       15 . The fluidized bed of  claim 14 , wherein the nanoporous metal oxide particles are aerogel particles. 
   
   
       16 . A purification system, wherein the system includes the fluidized bed of  claim 14 . 
   
   
       17 . A method for purifying a fluid system, the method comprising:
 a. directing the fluid system to an inverse fluidized bed comprising a nanoporous metal oxide material having a density lower than the density of the fluid system; and   b. contacting the fluid system with the nanoporous metal oxide material, thereby removing contaminants from the fluid system to obtain a purified fluid.   
   
   
       18 . The method of  claim 17 , wherein the contaminant is an organic material and the fluid system is a wastewater stream. 
   
   
       19 . The method of  claim 17 , wherein the nanoporous metal oxide material is a particulate aerogel. 
   
   
       20 . The method of  claim 19 , wherein the aerogel is a hydrophobic silica aerogel. 
   
   
       21 . The method of  claim 17 , wherein the nanoporous metal oxide is an oxide of a metal selected from the group consisting of silicon, aluminum, zirconium, titanium, hafnium, vanadium, yttrium and any combination thereof 
   
   
       22 . The method of  claim 17 , wherein a difference between the density of the fluid system and that of the nanoporous metal oxide material is at least about 0.1 g/cm 3 . 
   
   
       23 . A purification process, wherein the process includes the method of  claim 17 . 
   
   
       24 . A method for removing an oil from an aqueous system, the method comprising contacting the aqueous system with an inversely fluidized hydrophobic material, wherein the hydrophobic material includes a nanoporous metal oxide, thereby removing at least a portion of the oil from the aqueous system. 
   
   
       25 . A purification process, wherein the process includes the method of  claim 24 .