Device for the cathodic protection of a metal wall against corrosion in a saline environment

Abstract

A device for the cathodic protection of a metal wall against corrosion in a saline environment, includes an anode and means for connecting said anode to said wall. The anode has a higher electrochemical potential than the wall, wherein the anode is placed in a compartment delimited by a wall permeable to electrons and, optionally, to water. The device includes a porous outer layer made from a material selected from: polymeric materials, ceramic materials or hydrated inorganic materials and at least one porous layer having the ability to collect the cations emitted by the anode during the dissolution of same. The material forming the at least one layer is selected from osmotic membranes, active carbon, a cation exchange resin such as a zeolite, a cation-collecting polymer with nanofillers, cation-collecting mineral compounds such as phyllosilicates and inosilicates, cation-retaining nanofiltering semi-permeable organic microporous membranes.

1 . A device for the cathodic protection of a metal wall against corrosion in a saline environment, comprising an anode and means for connection of said anode to said wall, said anode being at a higher electrochemical potential than said wall, wherein said anode is placed in a compartment delimited by a wall that is permeable to electrons and, optionally, to water, comprising:
 a porous outer layer of a material selected from: polymer materials, ceramic materials or hydrated inorganic materials;   and at least one porous layer able to capture the cations emitted by the anode during dissolution of the latter, the material constituting said at least one layer being selected from osmotic membranes, activated charcoal, a cation exchange resin such as a zeolite, a cation capture polymer with nanofillers, cation capture mineral compounds such as phyllosilicates and inosilicates, semipermeable organic microporous nanofiltration membranes of a type that retains cations.   
     
     
         2 . The device as claimed in  claim 1 , wherein said wall also comprises a membrane that traps negatively charged pollutants. 
     
     
         3 . The device as claimed in  claim 1 , wherein the anode is a sacrificial anode whose electrochemical potential is naturally higher than that of the metal wall. 
     
     
         4 . The device as claimed in  claim 1  wherein it comprises means for applying an electrochemical potential greater than that of the metal wall to the anode. 
     
     
         5 . The device as claimed in  claim 1 , wherein the means for connection of the anode to the metal wall are in contact with the wall outside the compartment and in that they pass through the porous wall of compartment hermetically. 
     
     
         6 . The device as claimed in  claim 1 , wherein the means for connection of the anode to the metal wall are in contact with the metal wall inside compartment, and in that the porous wall of compartment is connected hermetically to the metal wall. 
     
     
         7 . The device as claimed in  claim 1 , wherein it comprises means for keeping the anode at a distance from the metal wall. 
     
     
         8 . The device as claimed in  claim 1 , wherein it comprises a plurality of layers able to capture the cations emitted by the anode during dissolution of the latter, each layer preferentially capturing cations different from those captured preferentially by the other layers.