Integrated CDI electrode

Patent metadata

Field	Value
Publication number	US-12454473-B2
Application number	US-201816958971-A
Country	US
Kind code	B2
Filing date	Dec 29, 2018
Priority date	Dec 30, 2017
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

Reduced graphene oxide@polystyrene (RGO-PS) composite was synthesized using reduced graphene oxide (RGO), styrene monomer and divinylbenzene through an in-situ polymerization process. The RGO-PS composite was functionalized with sulfonate and quaternary amine functionalities for making positive and negative integrated electro-adsorbent-ion exchange resins (EAIERs), respectively. These EAIERs ‘molecular constructs’ were used as CDI electrodes and desalination was performed for the removal of different ions. A high electro-adsorption capacity of ˜15.93 mg/g for Cl− using 802 μS NaCl solution was observed in laboratory batch experiments which was much higher than the adsorption capacity of RGO electrodes reported earlier (˜2-3 mg/g).

First claim

We claim:

1 . An electrode assembly for capacitive deionization (CDI) comprising:
a) at least one electrode made of chemically-linked cation exchange resin molecular constructs synthesized by in-situ polymerization of a styrene resin monomer and a two-dimensional material selected from the group consisting of reduced graphene oxide (RGO), molybdenum disulfide (MoS 2 ), tungsten diselenide (WSe 2 ), tungsten disulfide (WS 2 ) and any combination thereof, the in-situ polymerization comprising mixing the styrene resin monomer with the two-dimensional material, to obtain a two-dimensional material polystyrene composite, followed by functionalization of the two-dimensional material polystyrene composite with a sulfonate and/or a carboxylate moiety; b) at least one electrode made of chemically-linked anion exchange resin molecular constructs synthesized by in-situ polymerization of a styrene resin monomer and a two-dimensional material selected from the group consisting of reduced graphene oxide (RGO), molybdenum disulfide (MoS 2 ), tungsten diselenide (WSe 2 ), tungsten disulfide (WS 2 ) and any combination thereof, to obtain a two-dimensional material-polystyrene composite, followed by functionalization of the two-dimensional material polystyrene composite with an amine moiety;
wherein, electro-desorption during CDI does not lead to readsorption and consequent reduction of adsorption capacity of a deionization system comprising the electrode assembly.

2 . The electrode assembly as claimed in claim 1 , wherein the two dimensional material is reduced graphene oxide (RGO).

3 . The electrode assembly as claimed in claim 1 , wherein the two-dimensional material polystyrene composite further comprises at least one other carbon material to enhance the adsorption performance of the CDI cell.

4 . The electrode assembly as claimed in claim 1 , that is configured to be used for removing salts from brackish water.

5 . The electrode assembly as claimed in claim 4 , that in operation removes cations of different charge.

6 . The electrode assembly as claimed in claim 4 , that in operation removes anions of different charge.

7 . The electrode assembly as claimed in claim 1 , that in operation removes positively and negatively charged ions from impure water.

8 . The electrode assembly as claimed in claim 1 , wherein the adsorption and desorption occur at equal efficiency for multiple cycles.

9 . The electrode assembly as claimed in claim 1 that is configured to be used along with other deionization and purification methods to enhance efficiency of removal of ions.

10 . The electrode assembly of claim 5 that in operation removes Fe 3+ , Mg 2+ and Na + ions.

11 . The electrode assembly of claim 6 that in operation removes Cl − , NO 3 − , F − , SO 4 2+ , arsenite and arsenate ions.

12 . The electrode assembly of claim 3 , wherein the additional carbon material is selected from the group consisting of carbon nanotubes (CNTs), fullerenes and carbon fibers.

13 . The electrode assembly of claim 1 , wherein the two dimensional material is RGO.

14 . The electrode assembly of claim 1 , wherein the molecular constructs a) and b) are prepared by in situ polymerization of polystyrene with divinylbenzene in the presence of a suspension of RGO.

Assignees

• Indian Inst Tech Madras
• Indian Institute Of Tech Iit Madras

Inventors

• Thalappil Pradeep
• Islam Md Rabiul
• Sengupta Soujit
• Pillalamarri Srikrishnarka
• Jana Sourav Kanti

Classifications

• C02F2001/46133

  characterised by the material · CPC title

• C02F1/46109

  Electrodes · CPC title

• C02F1/4691 Primary

  Capacitive deionisation · CPC title