Method and device for pure hydrogen generation from acidic solution

Abstract

The present development is a method for generating pure hydrogen from an organic acid solution and a zero-valent metal. By reacting the metal with the organic acid rather than a mineral acid, hydrogen generation occurs at a gradual and more consistent rate than is observed by prior art methods, making the present method suitable for fuel cell applications. A portable hydrogen-generating device using the method of generating pure hydrogen from acidic solution is further disclosed.

1 . The method comprising the steps of: 
 (a) reacting a zero-valent metal with an organic acid, thereby forming a metal-O—CO—R complex;    (b) removing the hydrogen produced by the reaction of the metal and acid;    (c) regenerating the organic acid by oxidizing the metal-O—CO—R complex by reacting the complex with an oxidizing agent; and,    (d) precipitating the metal as a metal oxide.    
   
   
       2 . The method of  claim 1  further including the addition of an oxidizing agent with the organic acid.  
   
   
       3 . The method of  claim 1  further including the step of reacting the metal oxide with a hydrocarbon to reduce the metal to the zero-valent state after precipitation of the metal oxide.  
   
   
       4 . The method of  claim 1  wherein the metal is selected from the group consisting of iron, zinc, copper, aluminum, nickel and a combination thereof.  
   
   
       5 . The method of  claim 1  wherein the organic acid is selected from the group consisting of carboxylic acids, formic acid, acetic acid, oxalic acid, and combinations thereof.  
   
   
       6 . The method of  claim 1  wherein the oxidizing agent in step (c) is selected from the group consisting of hydrogen peroxide, starches and sugars.  
   
   
       7 . The method of  claim 1  wherein the oxidizing agent in step (c) comprises oxygen or ozone.  
   
   
       8 . A portable hydrogen-generating device comprising a case housing (i) a first cartridge filled with a metal and (ii) recycle column filled with an organic acid solution, wherein said recycle column is plumbed to said cartridge, and a variable speed pump connected to the system so as to move said acid solution between the active reaction cartridge and the recycle column.  
   
   
       9 . The device of  claim 8  further including a second replacement cartridge filled with metal plumbed to said recycle column.  
   
   
       10 . The device of  claim 8  further including at least one valve within the plumbing to allow said recycle column to be in communication with each cartridge separately.  
   
   
       11 . The device of  claim 8  wherein said recycle column further includes an oxidizing agent.  
   
   
       12 . The device of  claim 8  further including a means for uniformly dispersing said organic acid solution.  
   
   
       13 . The device of  claim 8  further including a means for venting gas from said case.  
   
   
       14 . A process for generation of hydrogen gas, comprising the following steps: 
 (a) bringing an organic acid, or solution thereof, into contact with a metal which dissolves in said acid with evolution of hydrogen;    (b) reacting the resulting solution containing said dissolved metal with an oxidizing agent; and    (c) regenerating said acid by precipitation of said dissolved metal in the form of an oxide.    
   
   
       15 . The process of  claim 14  comprising the additional step of passing the evolved hydrogen through a hydrogen-permeable membrane.  
   
   
       16 . The process of  claim 14  wherein said metal comprises iron.  
   
   
       17 . The process of  claim 14  wherein said oxidizing agent comprises oxygen, ozone, or hydrogen peroxide.  
   
   
       18 . The process of  claim 14  wherein said oxidizing agent comprises hydrogen peroxide.  
   
   
       19 . The process of  claim 14  wherein said organic acid contains a —COOH group.  
   
   
       20 . The process of  claim 14  wherein said organic acid is selected from the group consisting of formic acid, acetic acid, oxalic acid, and combinations thereof.