Electrochemical deposition for metal ion extraction/removal from water

Patent metadata

Field	Value
Publication number	US-10981793-B2
Application number	US-201716098852-A
Country	US
Kind code	B2
Filing date	Jun 29, 2017
Priority date	Jun 30, 2016
Publication date	Apr 20, 2021
Grant date	Apr 20, 2021

Abstract

A method for extracting metal ions from water is provided that includes disposing two electrically conductive electrodes in water, where the water includes a target ion species in solution, where at least one of the electrically conductive electrodes is a functionalized electrode having species-specific adsorption of the target ion species, and providing electrical current to the electrically conductive electrodes such that the one or more target ion species are deposited to metallic form or metal oxides at the functionalized electrode by one or more electrochemical reactions.

First claim

What is claimed:

1. A method for extracting metal ions from water, comprising:
disposing two electrically conductive electrodes in water, wherein said water comprises a target ion species in solution, wherein at least one of the electrically conductive electrodes is a working electrode having species-specific adsorption of said target ion species, wherein the working electrode comprises fibers of a carbon-based material covered with a porous coating; and
providing electrical current to said electrically conductive electrodes such that the one or more target ion species are deposited to metallic form or metal oxides at said working electrode by one or more electrochemical reactions.

2. The method according to claim 1 , wherein said electrical current comprises an alternate current or direct current.

3. The method according to claim 1 , wherein the carbon-based material comprises one of carbon felt, carbon fibers, carbon nanotubes, carbon blacks, activated carbon, graphite plates, graphene, or graphene oxides.

4. The method according to claim 3 , wherein said working electrode is functionalized with amidoxime-based chemicals.

5. The method according to claim 1 , wherein a voltage across said electrodes alternates between a negative value and zero.

6. The method according to claim 1 , wherein said water comprises seawater, lake water, river water, domestic wastewater, industrial waste water or drinking water.

7. The method according to claim 1 , wherein said target ion species is selected from the group consisting of uranium, vanadium, copper, silver, gold, cadmium, lead, mercury, cobalt, rhodium, iridium, nickel, palladium, platinum, and rare earth metals.

8. The method according to claim 1 ,
wherein all said target ions are randomly distributed in the aqueous solution,
wherein when a negative bias is applied, said target ions will start to migrate according to an external electrical field,
wherein an electrical double layer on the surface of said working electrode is formed,
wherein said target ions in an inner layer of the said electrical double layer form chelation binding to a surface of said working electrode,
wherein a metallic species of said target ion is reduced and electrodeposited as a charge neutral species to said working electrode,
wherein when the bias is removed said target ions and said electrodeposited target metallic species are left attached to said working electrode surface,
wherein other ions without specific binding redistribute on said working electrode surface and release from surface active sites,
wherein as said negative bias repeats, more target ions will attach to said working electrode surface and said electrodeposited target metallic species are further deposited to grow into bigger particles relative to said target ion.

Assignees

• Univ Leland Stanford Junior

Inventors

• Liu Chong
• Cui Yi
• Wu Tong

Classifications

• C25C1/12

  of copper · CPC title

• C22B7/006 Primary

  Wet processes · CPC title

• C25C1/16

  of zinc, cadmium or mercury · CPC title

• Y02P10/20

  Recycling · CPC title

• C25C1/20

  of noble metals · CPC title