Electrochemical enhancement of detergent alkalinity

• US 8,937,037 B2
• Filed: 03/02/2011
• Issued: 01/20/2015
• Est. Priority Date: 03/02/2011
• Status: Active Grant

• Current Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Original Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Inventors: Smith, Kim R., Olson, Erik C.
• Primary Examiner(s): Choi, Ling
• Assistant Examiner(s): NGUYEN, THUY-AI N
• Application Number:
  US13/038,705
• Publication Number:
  US 20120225801A1
• Time in Patent Office: 1,420 Days
• Field of Search: 510/218
• US Class Current: 510/218
• CPC Class Codes: C11D 7/12 Carbonates bicarbonates
• CPC Class Codes: C25B 1/00 Electrolytic production of inorganic compounds or non-metals
• CPC Class Codes: C25B 1/04 by electrolysis of water
• CPC Class Codes: C25B 1/16 Hydroxides by simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine C25B1/34
• CPC Class Codes: C25B 9/73 of the filter-press type
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis

Abstract

A device for in-situ production of caustic and increasing alkalinity of a detergent and methods for increasing alkalinity of a detergent are disclosed. In particular, in situ electrochemical conversion of bicarbonate, sesquicarbonate or carbonate sources into caustic provides a safe means for increasing alkalinity of a detergent for a variety of cleaning applications. The invention further discloses methods for cleaning using the electrochemically enhanced detergent according to the invention.

Claims

1. A method for increasing alkalinity of a detergent comprising:

(a) providing an electrochemical cell configured with at least one hydrogen consuming anode, at least one hydroxide producing cathode and an ion-selective membrane;

(b) introducing an electrolyte solution into said electrochemical cell, wherein said solution comprises

a catholyte comprising a detergent composition having a neutral pH, and

an anolyte selected from the group consisting of an alkali metal carbonate, alkali metal bicarbonate, alkali metal sesquicarbonate and mixtures thereof; and

(c) applying an electric current across said anode and cathode for electrochemical production of hydroxide and hydrogen at said cathode and carbon dioxide and water at said anode and said electrochemical production of hydroxide increases the pH of said detergent to at least 12.

2. The method of claim 1 wherein said electrochemical production of hydroxide increases the pH of said detergent to greater than 12.

3. The method of claim 1 wherein said catholyte is a carbonate detergent composition and said electrochemical production of hydroxide increases the pH of said detergent to greater than 12.

4. The method of claim 1 further comprising introducing said hydroxide produced by said electrochemical cell to a detergent composition outside of said electrochemical cell, wherein said hydroxide increases the pH of said detergent to greater than 12.

5. The method of claim 1 wherein said detergent is carbonate-free.

6. The method of claim 1 further comprising adding a threshold agent to said electrochemical cell in the amount of up to about 10,000 ppm, wherein said threshold agent is a water soluble polycarboxylate having a molecular weight less than 5,000 selected from the group consisting of homopolymers and copolymers of polyacrylates, polyolefinic systems, polymaleic systems, derivatives and salts of the same, and combinations of the same.

7. The method of claim 1 further comprising adding at least one additional component to said electrolyte solution or detergent composition selected from the group consisting of a builder, threshold agent, surfactant, rinse aid, bleaching agent, bleach catalyst, sanitizer or antimicrobial agent, defoaming agent, solidification agent, anti-redeposition agent, optical brightener, dye, odorant, hardening agent, solubility modifier, corrosion inhibitor, magnesium sources or resins, enzyme or combinations thereof.

8. A device for in-situ production of caustic and increasing alkalinity of a detergent comprising:

(a) an electrochemical cell configured with at least one hydrogen consuming anode, at least one hydroxide producing cathode and an ion-selective membrane, wherein an electric current is applied across said anode and cathode for electrochemical production of hydroxide and hydrogen at said cathode and carbon dioxide and water at said anode;

(b) an electrolyte solution source for said electrochemical cell, wherein said electrolyte solution comprises

a catholyte comprising a detergent composition, and

an anolyte selected from the group consisting of an alkali metal carbonate, alkali metal bicarbonate, alkali metal sesquicarbonate and mixtures thereof; and

(c) an outlet for dispensing a product stream of the detergent having an increased pH of at least 12 exiting from the electrochemical cell.

9. The device of claim 8 wherein said ion-selective membrane is a micro porous membrane, micro porous diaphragm or a cation exchange membrane.

10. The device of claim 8 wherein said anode is steel and said cathode is titanium.

11. The device of claim 8 further comprising a dispenser in fluid communication with said electrochemical cell, wherein said dispenser provides an electrolyte solution comprising a detergent composition with a source of an alkali metal carbonate, alkali metal bicarbonate, alkali metal sesquicarbonate or combinations thereof.

12. The device of claim 8 further comprising a dispenser in fluid communication with said outlet and product stream of caustic, wherein said dispenser provides a detergent composition, wherein said caustic increases the alkalinity of said detergent composition to a pH greater than 12, and wherein said outlet is in fluid communication with a cleaning system such as a ware wash machine.

13. The device of claim 8 wherein said catholyte is a detergent composition that is carbonate-free and said electrochemical production of hydroxide increases the pH of said detergent to greater than 12.

14. The device of claim 8 wherein said electrolyte solution further comprises a threshold agent in the amount of up to about 10,000 ppm, wherein said threshold agent is a water soluble polycarboxylate having a molecular weight less than 5,000 selected from the group consisting of homopolymers and copolymers of polyacrylates, polyolefinic systems, polymaleic systems, derivatives and salts of the same, and combinations of the same.

15. The device of claim 8 wherein said electrolyte solution or detergent composition further comprises a source of a builder, threshold agent, surfactant, rinse aid, bleaching agent, bleach catalyst, sanitizer or antimicrobial agent, defoaming agent, solidification agent, anti-redeposition agent, optical brightener, dye, odorant, hardening agent, solubility modifier, corrosion inhibitor, magnesium sources or resins, enzyme or combinations thereof.

16. A method for cleaning using an electrochemically enhanced detergent comprising:

(a) obtaining a detergent composition having an increased pH of at least 12 from an electrochemical cell, said cell comprising;

(i) at least one hydrogen consuming anode, at least one hydroxide producing cathode and an ion-selective membrane, wherein an electric current is applied across said anode and cathode for electrochemical production of hydroxide and hydrogen at said cathode and carbon dioxide and water at said anode;

(ii) an electrolyte solution source for said electrochemical cell, wherein said electrolyte solution comprises a detergent composition and a source of an alkali metal carbonate, alkali metal bicarbonate, alkali metal sesquicarbonate or mixtures thereof;

(iii) an outlet for dispensing a product stream of an electrochemically enhanced detergent having a pH of at least 12; and

(b) contacting an article with said electrochemically enhanced detergent, such that the article is cleaned.

17. The method of claim 16 wherein said detergent composition is carbonate-free and has a neutral pH.

18. The method of claim 16 wherein said detergent composition obtained from said electrochemical cell has a pH of greater than 12.