Method for manufacturing a filter capable of trapping carcinogens and toxic chemicals

Abstract

A method for manufacturing a filter is introduced. Firstly, a polyurethane material including a urethane-based main chain having a repeat unit of the formula, (R—NH—COO—R—O—NH) n , with a plurality of contaminants absorbed around the urethane-based main chain is provided. Then, an extraction is performed to remove the contaminants from the urethane-based main chain so as to reveal a plurality of absorption sites for trapping cyanides, phenols, or polynuclear aromatic compounds.

What is claimed is:  
     
         1 . A method for manufacturing a filter comprising: providing a polyurethane material comprising a urethane-based main chain having a repeat unit of the formula, (R—NH—COO—R—O—NH) n , with a plurality of contaminants absorbed around the urethane-based main chain; and performing an extraction to remove the contaminants from the urethane-based main chain so as to reveal a plurality of absorption sites for trapping cyanides, phenols, or polynuclear aromatic compounds; wherein the R group is an aliphatic chain and the R group is an aromatic group.  
     
     
         2 . The method of  claim 1  wherein each of the absorption sites is selected from the group consisting of the NH moiety, the R group, and the R group.  
     
     
         3 . The method of  claim 2  wherein the nitrogen atom of the NH moiety has a lone pair electron for binding the phenols and the cyanides via hydrogen bonds.  
     
     
         4 . The method of  claim 2  wherein the R group and the R group absorb the polynuclear aromatic compounds via van der Waals attraction.  
     
     
         5 . The method of  claim 2  wherein the NH moiety is originally occupied by the contaminants comprising phenols.  
     
     
         6 . The method of  claim 5  wherein the phenols comprise 6-tert-butyl-2,4-dimethylphenol and butylated methyl phenol.  
     
     
         7 . The method of  claim 2  wherein the R group and the R group are originally occupied by the contaminants comprising tinuvin, monomers, dimers, oligomers, and 4,4,5,6-tetramethyltetrahydro-1,3-oxazin-2-thione.  
     
     
         8 . The method of  claim 1  wherein the R group comprises n-octyl.  
     
     
         9 . The method of  claim 1  wherein the R″ group comprises tolyl.  
     
     
         10 . The method of  claim 1  wherein the extraction is a Soxhlet extraction.  
     
     
         11 . The method of  claim 10  wherein the Soxhlet extraction uses a solvent containing 6% ether in hexane to extract the contaminants from the polyurethane material for revealing the urethane-based main chain.  
     
     
         12 . The method of  claim 10  wherein the Soxhlet extraction uses a solvent comprising methylene chloride, hexane, light hydrocarbon based solvents, or mixtures of the foregoing to extract the contaminants from the polyurethane material for revealing the urethane-based main chain.  
     
     
         13 . The method of  claim 1  wherein the extraction is a supercritical fluid extraction, a steam distillation, a hot solvent extraction, or an organic extraction.  
     
     
         14 . The method of  claim 1  further comprising drying the urethane-based main chain for forming the filter.  
     
     
         15 . The method of  claim 1  wherein the polyurethane material is polyurethane foam or polyurethane fiber.  
     
     
         16 . The method of  claim 1  wherein the polynuclear aromatic compounds comprise 2-methylnaphthalene, acenaphthylene, acenaphthene, dibenzofuran, fluorene, phenanthrene, anthracene, carbazole, fluoranthene, pyrene, benzo(a)anthracene, and chrysene.  
     
     
         17 . The method of  claim 1  wherein the polyurethane material has a density of between about 0.01 g/ml to about 0.05 g/ml.