Electrochemical Oxidation of Organic Matter

Abstract

Carbonaceous feedstock is at least partially oxidized using a concentrated metal ion solution that is regenerated in an electrochemical hydrogen gas producing process. The at least partially oxidized feedstock and/or hydrogen are then advantageously used as an energy carrier in a downstream process.

1 . A method of oxidizing a carbonaceous feedstock, comprising:
 combining a metal and a solubility-enhancing compound to form a metal-containing solution;   wherein the solubility-enhancing compound is present at a concentration and has a composition effective to increase solubility of the metal over solubility of the same metal in sulfuric acid in an amount of at least 10%;   wherein the solubility-enhancing compound has a composition effective to resist oxidation under conditions at which the metal is electrochemically oxidized from a reduced form;   combining the carbonaceous feedstock with the metal-containing solution to thereby at least partially oxidize the feedstock and form the reduced form of the metal;   optionally electrochemically regenerating the metal from the reduced form of the metal, wherein the step of regenerating is carried out under conditions effective to produce hydrogen; and   using at least one of the hydrogen and the at least partially oxidized feedstock as an energy carrier in a subsequent reaction.   
   
   
       2 . The method of  claim 1  wherein the carbonaceous feedstock comprises a material selected from the group consisting of a cellulosic material, lignocellulosic material, paper, cotton, plant materials, coal, tar, and coke. 
   
   
       3 . The method of  claim 1  wherein the metal is a transition metal ion. 
   
   
       4 . The method of  claim 3  wherein the transition metal ion is a period 4 transition metal ion. 
   
   
       5 . The method of  claim 3  wherein the transition metal ion is selected from the group consisting of an iron ion, a copper ion, and a manganese ion. 
   
   
       6 . The method of  claim 1  wherein the solubility-enhancing compound comprises an organic acid that comprises a sulfur atom, and wherein the solubility-enhancing compound is not sulfuric acid. 
   
   
       7 . The method of  claim 1  wherein the solubility-enhancing compound is an optionally substituted alkyl sulfonic acid or an optionally substituted alkyl sulfamic acid. 
   
   
       8 . The method of  claim 1  wherein the solubility-enhancing compound is present at a concentration effective to increase solubility of the metal over solubility of the same metal in sulfuric acid in an amount of at least 50%. 
   
   
       9 . The method of  claim 1  wherein the solubility-enhancing compound is present at a concentration effective to increase solubility of the metal over solubility of the same metal in sulfuric acid in an amount of at least 100%. 
   
   
       10 . The method of  claim 1  wherein the metal-containing solution has an acid pH of between pH 2.0 and pH 6.0. 
   
   
       11 . The method of  claim 1  wherein the step of at least partially oxidizing the feedstock is performed at a temperature between 20° C. and 50° C. 
   
   
       12 . The method of  claim 1  wherein the step of at least partially oxidizing the feedstock is performed at a temperature between 50° C. and 300° C. 
   
   
       13 . The method of  claim 1  wherein the metal is electrochemically regenerated. 
   
   
       14 . The method of  claim 1  wherein the metal is electrochemically regenerated in a divided cell under conditions such that the hydrogen is produced in only one side of the cell without oxygen production in another side of the cell. 
   
   
       15 . The method of  claim 1  wherein the hydrogen is used in a fuel cell to generate energy. 
   
   
       16 . The method of  claim 1  wherein the at least partially oxidized feedstock is used as a feed component in a fermentation. 
   
   
       17 . A liquid intermediate in the oxidation of a carbonaceous feedstock comprising (1) an organic acid other than sulfuric acid, (2) a transition metal ion, and (3) a carbonaceous feedstock selected from the group consisting of an oligosaccharide, a polysaccharide, coal, tar, and coke. 
   
   
       18 . The intermediate of  claim 17  wherein the organic acid comprises an optionally substituted alkyl sulfonic acid or an optionally substituted alkyl sulfamic acid, optionally further comprising a complexing agent. 
   
   
       19 . The intermediate of  claim 17  wherein the transition metal ion is selected from the group consisting of an iron ion, a copper ion, and a manganese ion. 
   
   
       20 . The intermediate of  claim 17  wherein the intermediate is an aqueous intermediate having a pH between 2.0 and 6.0.