Metal nanoparticle-deposited, nitrogen-doped carbon adsorbents for removal of sulfur impurities in fuels

Abstract

Metal nanoparticle-deposited, nitrogen-doped carbon adsorbents are disclosed, along with methods of removing sulfur compounds from a hydrocarbon feed stream using these adsorbents.

We claim: 
     
         1 . A metal nanoparticle-deposited, nitrogen-doped carbon adsorbent, produced by a process comprising:
 a) contacting at least one nitrogen precursor and a suitable first metal-containing salt in a first strong acid solution;   b) contacting a product of a) and an oxidant;   c) heating a product of b) in an inert atmosphere;   d) contacting a product of c) with a second strong acid solution;   e) heating a product of d) in an inert atmosphere, and   f) contacting the product of e) with a second metal-containing salt;   
       thereby producing the metal nanoparticle-deposited, nitrogen-doped carbon adsorbent. 
     
     
         2 . The adsorbent of  claim 1 , wherein the second metal-containing salt is a gold-containing salt, and the metal nanoparticle-deposited, nitrogen-doped carbon adsorbent is a gold nanoparticle-deposited, nitrogen-doped carbon adsorbent. 
     
     
         3 . The adsorbent of  claim 1 , wherein said a) is contacting two nitrogen precursors and the suitable first metal-containing salt in a first strong acid solution. 
     
     
         4 . The adsorbent of  claim 3 , wherein said two nitrogen precursors are a first nitrogen precursor which is aniline and a second nitrogen precursor which is cyanimide. 
     
     
         5 . The adsorbent of  claim 1 , wherein said b) is contacting the product of a) and (NH 4 ) 2 S 2 O 8 , thus forming an oxidized product, and contacting said oxidized product with an aqueous solution containing carbon black and a low molecular weight alcohol. 
     
     
         6 . The adsorbent of  claim 1 , wherein said c) is heating the product of b) to a first temperature of from about 35° C. to about 100° C., and then to a second temperature of from about 500° C. to about 1000° C. 
     
     
         7 . The adsorbent of  claim 1 , wherein said d) is contacting the product of c) with either an H 2 SO 4  solution or a HNO 3  solution. 
     
     
         8 . The adsorbent of  claim 1 , wherein said e) is heating the product of d) from about 500° C. to about 1000° C. 
     
     
         9 . The absorbent of  claim 1 , wherein f) does not comprise a reducing agent. 
     
     
         10 . The absorbent of  claim 1 , wherein f) comprises a reducing agent. 
     
     
         11 . A method for removing sulfur compounds from a hydrocarbon feed stream comprising:
 A) providing a first hydrocarbon feed stream, which is contaminated with the sulfur compounds; and   B) passing the first hydrocarbon feed stream through a desulfurization system comprising the metal nanoparticle-deposited, nitrogen-doped carbon adsorbent, to produce a second hydrocarbon feed stream which has about 30% to about 99.9% by weight less of the sulfur compounds than the first hydrocarbon feed stream, wherein the metal nano-particle-deposited, nitrogen-doped carbon absorbent is produced by a process comprising:
 a) contacting at least one nitrogen precursor and a suitable first metal-containing salt in a first strong acid solution; 
 b) contacting a product of a) and an oxidant; 
 c) heating a product of b) in an inert atmosphere; 
 d) contacting a product of c) with a second strong acid solution; 
 e) heating a product of d) in an inert atmosphere, and 
 f) contacting the product of e) with a second metal-containing salt. 
   
     
     
         12 . The method of  claim 11 , wherein the hydrocarbon feed stream is a liquid hydrocarbon feed stream. 
     
     
         13 . The method of  claim 12 , wherein the liquid hydrocarbon feed stream is selected from the group consisting of diesel fuel, jet fuel, gasoline, kerosene, compressed natural gas, and liquefied petroleum gas (LPG). 
     
     
         14 . The method of  claim 11 , wherein the sulfur compounds comprise dibenzothiophene (DBT). 
     
     
         15 . The method of  claim 11 , wherein the sulfur compounds comprise 4,6-dimethyldibenzothiophene (DMDBT). 
     
     
         16 . A method of making a metal nanoparticle-deposited, nitrogen-doped carbon adsorbent, the method comprising:
 a) contacting at least one nitrogen precursor and a suitable first metal-containing salt in a first strong acid solution;   b) contacting a product of a) and an oxidant;   c) heating a product of b) in an inert atmosphere;   d) contacting a product of c) with a second strong acid solution;   e) heating a product of d) in an inert atmosphere, and   f) contacting the product of e) with a second metal-containing salt.   
     
     
         17 . The method of  claim 16 , wherein the second metal-containing salt is a gold-containing salt, and the metal nanoparticle-deposited, nitrogen-doped carbon adsorbent is a gold nanoparticle-deposited, nitrogen-doped carbon adsorbent. 
     
     
         18 . The method of  claim 16 , wherein said c) is heating the product of b) to a first temperature of from about 35° C. to about 100° C., and then to a second temperature of from about 500° C. to about 1000° C. 
     
     
         19 . The method of  claim 16 , wherein said e) is heating the product of d) from about 500° C. to about 1000° C. 
     
     
         20 . The method of  claim 16 , wherein f) does not comprise a reducing agent.