Metal Coated Substrates for Filters

Abstract

An anti-microbial metal coating may be applied to filter membranes for use in actively depressing microbial viability in filtration applications. The anti-microbial metal coating may be applied to substrates that are considered to be sensitive to damage by conventional metal coating techniques or resistant to metal bonding. The coating may be applied from a salt absorbed to the substrate in solution, converted to a reducible form with a conversion agent, and reduced to active metal format through a low temperature plasma treatment.

1 . A filtration system, comprising:
 a filter including a porous substrate having a metal coating on at least one surface thereof, wherein the metal coating is reduced from a metal salt at ambient temperature, and exhibits a surface resistivity of less than 1×10 12 Ω/□, and wherein the filter contains through pores extending continuously through the porous substrate and the metal coating.   
     
     
         2 . The filtration system as in  claim 1  wherein the porous substrate is wettable by water. 
     
     
         3 . The filtration system as in  claim 2  wherein the porous substrate is selected from cellulose, blends containing cellulose, porous polyamides, porous polyether sulfone, porous polybenzimidazole, porous glass, and porous ceramic. 
     
     
         4 . The filtration system as in  claim 1  wherein the metal coating is bound to the surface of the porous substrate without additives, fillers, or interfacial layers. 
     
     
         5 . The filtration system as in  claim 1  wherein the metal coating is selected from copper, silver, cobalt, nickel, tin, zinc, palladium, and combinations thereof. 
     
     
         6 . The filtration system as in  claim 1  wherein the metal coating exhibits a surface resistivity of less than 1×10 6 Ω/□. 
     
     
         7 . The filtration system as in  claim 1  wherein the metal coating exhibits a surface resistivity of less than 1×10 1 Ω/□. 
     
     
         8 . The filtration system as in  claim 1  wherein the filter is effective in reactive electrochemical filtration. 
     
     
         9 . The filtration system as in  claim 1  wherein the metal coating is reduced from a metal salt under a plasma environment. 
     
     
         10 . The filtration system as in  claim 9  wherein the metal salt is selected from a metal hydroxide and a metal oxide. 
     
     
         11 . A method for treating a fluid, comprising:
 providing a filter including a porous substrate having a metal coating that is reduced from a metal hydroxide or a metal oxide at ambient temperature; and   contacting the metal coating of the filter with the fluid to cause an electrochemical interaction between the filter and the fluid.   
     
     
         12 . The method as in  claim 11 , including recovering a treated product as the filtrate.