Catalytic biomass conversion

Abstract

A biorefining method of processing a lignocellulosic biomass to separate lignin and hemicellulose from cellulose includes the steps of (a) reacting the biomass in an aqueous slurry having a pH less than 7, comprising a transition metal catalyst, hydrogen peroxide; and (b) separating a solid cellulose fraction from dissolved lignin and hemicellulose fractions. The method may also be used to treat cellulose and produce microcrystalline or nanocrystalline cellulose. The transition metal catalyst may be a nanoparticulate catalyst including multivalent iron, iron oxides and iron hydroxides. The nanoparticulate catalyst may be formed by oxidizing a highly reduced solution of iron, such as groundwater that has not been exposed to oxygen.

What is claimed is: 
     
         1 . A method of producing a nanoparticulate catalyst comprising multivalent iron from an aqueous solution, comprising the steps of:
 (a) oxidizing or allowing to oxidize the aqueous solution comprising multivalent iron;   (b) collecting precipitated nanoparticles or aggregated nanoparticles.   
     
     
         2 . The method of  claim 1  wherein the aqueous solution comprises groundwater. 
     
     
         3 . The method of  claim 2  comprising the further step of amending the aqueous solution with one or more additional transition metals, prior to the oxidation step. 
     
     
         4 . The method of  claim 3  wherein the aqueous solution is amended with copper ions. 
     
     
         5 . A nanoparticulate catalyst comprising multivalent iron, at least one iron oxide and at least one iron hydroxide. 
     
     
         6 . The catalyst of  claim 5  further comprising calcium carbonate. 
     
     
         7 . A method of using a nanoparticulate catalyst of  claim 5  to produce crystaline cellulose from biomass comprising the steps of:
 (a) reacting the biomass in an aqueous slurry having a pH less than 7, comprising the catalyst and hydrogen peroxide. 
 
     
     
       What is claimed is: 
     
     
         1 . A method of producing a nanoparticulate catalyst comprising multivalent iron from an aqueous solution, comprising the steps of:
 (a) oxidizing or allowing to oxidize the aqueous solution comprising multivalent iron;   (b) collecting precipitated nanoparticles or aggregated nanoparticles.   
     
     
         2 . The method of  claim 1  wherein the aqueous solution comprises groundwater. 
     
     
         3 . The method of  claim 2  comprising the further step of amending the aqueous solution with one or more additional transition metals, prior to the oxidation step. 
     
     
         4 . The method of  claim 3  wherein the aqueous solution is amended with copper ions. 
     
     
         5 . A nanoparticulate catalyst comprising multivalent iron, at least one iron oxide and at least one iron hydroxide. 
     
     
         6 . The catalyst of  claim 5  further comprising calcium carbonate, 
     
     
         7 . A method of using a nanoparticulate catalyst of  claim 5  to produce crystaline cellulose from biomass comprising the steps of:
 (a) reacting the biomass in an aqueous slurry having a pH less than 7, comprising the catalyst and hydrogen peroxide.