# US 4,396,474 A · Modified carbon or graphite fibrous percolating porous electrode, its use in electrochemical reactions

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- Number: US 4,396,474 A
- Document ID: US4396474A
- Status: Granted
- Kind: A
- Application number: 06/326,838
- Filed: 1981-12-03
- Granted: 1983-08-02
- Earliest claimed: 1979-12-18
- Assignees: Societe Nationale Elf Aquitaine
- Inventors: Michel Astruc; Pierre-Yves Guyomar; Catherine Lestrade
- Web page: https://patentgrep.com/patent/US4396474A

## CPC

- C25C 7/02: Electrodes (consumable anodes for the refining the metals C25C1/00 - C25C5/00); Connections thereof
- C02F 1/46109: {Electrodes}
- C02F 1/4672: {by electrooxydation}
- C02F 1/4678: {of metals}
- C02F 2001/46133: {characterised by the material}
- C02F 2001/46161: {Porous electrodes}
- C02F 2101/18: Cyanides
- C25C: PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)

## Abstract

This invention concerns a fibrous percolating porous electrode of the type containing a fibrous porous matrix made of carbon or graphite. The fibrous porous matrix, such as a carbon or graphite felt, is modified, for example by impregnation with a surface-active agent, and in the wetted state its apparent density in relation to water possesses specific values.

## Claims

### Claim 1

A method for the electrochemical reaction of a non-fused salt material in a liquid phase solution which comprises percolating a solution containing the material to be electrochemically reacted through a percolating porous electrode comprising a fibrous carbon or graphite porous matrix impregnated with a surface active agent having an apparent density in relation to water, in the wetted state, between 1.6 and three times the apparent density in relation to water of the corresponding non-impregnated fibrous porous matrix in the wetted state and establishing a potential difference between the percolating porous electrode and a counter electrode in contact with the solution.

### Claim 2 (depends on 1)

The method of claim 1 for recovering metals by electrodeposition wherein said material is a metal ion selected from the group consisting of copper, lead, silver, gold, mercury, cadmium and nickel in an aqueous solution.

### Claim 3 (depends on 1)

The method of claim 1 wherein said material is a contaminant selected from the group consisting of organic polluting agents and cyanide ions contained in waste water.

### Claim 4 (depends on 1)

The method of claim 1 wherein said material is an organic composition subject to one or more electrochemical reactions.

### Claim 5 (depends on 1)

The method of claim 1 further comprising regenerating the percolating porous electrode when it becomes clogged by metallic impurities.

### Claim 6 (depends on 1)

The method of claim 1 wherein said material is in an aqueous solution.