Method of removing organic materials using aqueous cleaning solutions

Abstract

Removal of water-insoluble organic residues from inorganic surfaces can be accomplished in aqueous cleaning solutions containing an oxidant at a preselected temperature wherein the pH is adjusted with respect to the isoelectric point of the surface material to be removed so that the pH is above the pK a and the isoelectric point of the surface for acid materials, and below the pK a and the isoelectric point of the surface for basic materials. Surfactants can also be added to the cleaning solution.

1 . A method of cleaning inorganic surfaces to remove water insoluble organic materials therefrom comprising 
 a) treating said surfaces with an aqueous solution including 
 i) an oxidant in an amount sufficient to convert non-polar residues to polar residues;  
 ii) a pH adjusting agent in an amount sufficient to provide a pH greater than the isoelectric point for acid-type materials and less than the isoelectric point for basic-type materials.  
   
   
   
       2 . A method according to  claim 1  wherein the temperature of the cleaning solution is maintained between about 40-100° C.  
   
   
       3 . A method according to  claim 1  wherein the oxidant is hydrogen peroxide.  
   
   
       4 . A method according to  claim 1  wherein the pH adjustment agent is ammonium hydroxide.  
   
   
       5 . A method according to  claim 1  wherein the pH adjustment agent is hydrogen chloride.  
   
   
       6 . A method according to  claim 1  wherein the aqueous solution further includes a surfactant.  
   
   
       7 . A method according to  claim 6  wherein the surfactant is a mixture of an anionic and a nonionic surfactant.  
   
   
       8 . A method according to  claim 6  wherein the surfactant is a mixture of a cationic and a nonionic surfactant.  
   
   
       9 . A method according to  claim 6  wherein the surfactant is a mixture of an anionic and a cationic surfactant.  
   
   
       10 . A mixture according to  claim 6  wherein the aqueous solution further includes a defoaming agent.