Carbon nanocomposite sorbent and methods of using the same for separation of one or more materials from a gas stream

Abstract

The present invention relates to carbon nanocomposite sorbents. The present invention provides carbon nanocomposite sorbents, methods for making the same, and methods for separation of a pollutant from a gas that includes that pollutant. Various embodiments provide a method for reducing the mercury content of a mercury-containing gas.

We claim: 
     
         1 . A method for reducing the mercury content of a mercury-containing gas, comprising:
 contacting at least part of a halogen- or halide-promoted carbon nanocomposite sorbent with the mercury, to form a mercury-sorbent composition, wherein the promoted carbon nanocomposite sorbent is a multiphase solid material having at least one phase having at least one dimension that is about 1-1000 nm or having a repeat distance separating at least some of the phases of about 1-1000 nm; and   separating at least some of the mercury-sorbent composition from the mercury-containing gas, to give a cleaned gas.   
     
     
         2 . The method of  claim 1 , further comprising promoting at least a portion of a carbon nanocomposite sorbent material comprising reacting the portion of the carbon nanocomposite sorbent material with a halogen or halide promoter to form the promoted carbon nanocomposite sorbent. 
     
     
         3 . The method of  claim 2 , wherein the promoting occurs in a scrubber, wherein the scrubber includes an aqueous slurry that includes the promoter. 
     
     
         4 . The method of  claim 2 , wherein the halogen or halide promoter is in a form comprising a vapor form, a solid form, in a solvent, or a combination thereof. 
     
     
         5 . The method of  claim 2 , wherein the halogen or halide promoter comprises at least one of Group V halide, Group VI halide, or a mixture thereof. 
     
     
         6 . The method of  claim 2 , wherein the halogen or halide promoter is NH 4 Br, NaBr, CaBr 2 , HBr, NaCl, CaCl 2 , HCl, or a combination thereof. 
     
     
         7 . The method of  claim 2 , wherein the halogen or halide promoter is NH 4 Br, NaBr, CaBr 2 , HBr, or a combination thereof. 
     
     
         8 . The method of  claim 2 , wherein about 1 g to about 30 g of promoter is used per about 100 g of carbon nanocomposite material. 
     
     
         9 . The method of  claim 2 , wherein a promoter precursor transforms into the halogen or halide promoter that reacts with the sorbent. 
     
     
         10 . The method of  claim 2 , wherein promoting comprises injecting the carbon nanocomposite sorbent material at an injection rate and injecting separately at least one promoter at an injection rate into a gas stream whereby in-flight reaction produces the promoted sorbent. 
     
     
         11 . The method of  claim 1 , wherein separating at least some of the mercury-sorbent composition from the mercury-containing gas comprises separating particulates from the mercury-containing gas, the particulates comprising at least some of the mercury-sorbent composition. 
     
     
         12 . The method of  claim 1 , wherein the promoted carbon nanocomposite sorbent combines with at least about 70 wt % of the mercury present in the mercury-containing gas. 
     
     
         13 . The method of  claim 1 , further comprising reducing the concentration of SO 2  or SO 3  in the mercury-containing gas. 
     
     
         14 . The method of  claim 1 , wherein the promoted carbon nanocomposite sorbent comprises a substrate material. 
     
     
         15 . The method of  claim 14 , wherein the substrate material comprises diatomaceous earth, clay, zeolite, a mineral, or a combination thereof. 
     
     
         16 . The method of  claim 14 , wherein the substrate material comprises diatomaceous earth, clay, zeolite, or a combination thereof. 
     
     
         17 . The method of  claim 1 , wherein the promoted carbon nanocomposite sorbent comprises a heat-treated carbon precursor. 
     
     
         18 . The method of  claim 17 , wherein the carbon precursor comprises a carbohydrate. 
     
     
         19 . The method of  claim 1 , wherein the promoted carbon nanocomposite sorbent comprises a heat-treated mixture of a carbon precursor and a substrate material. 
     
     
         20 . The carbon nanocomposite sorbent of  claim 1 , wherein the promoted carbon nanocomposite sorbent comprises binding sites formed by reaction or impregnation with the halogen or halide promotor, wherein the binding sites are mercury-absorbant.