Claims
- 1. A method for measuring the buffering capacity of a liquid containing dissolved oxygen which comprises:
- (a) providing a liquid containing dissolved oxygen;
- (b) providing a cathodically or anodically polarized metal surface immersed in said liquid;
- (c) connecting electrical circuits to apply a constant cathodic potential between (1) a working electrode and a reference electrode and (2) to provide means for measuring the difference in potential between a pH microelectrode and a reference electrode;
- (d) applying a known potential to said metal surface;
- (e) treating said liquid to create a constant bulk dissolved oxygen concentration;
- (f) measuring the differences in pH at said metal surface;
- (g) determining the buffering capacity of said liquid from said pH measurement and said known potential.
- 2. The method of claim 1, wherein the pH of said liquid is measured at said cathodically or anodically polarized metal surface by means of a pH electrode which is positioned at or adjacent to said metal surface.
- 3. The method of claim 1, wherein said applied potential is adjusted so as to cause a predetermined change in the measured pH of said liquid.
- 4. The method of claim 1, wherein said liquid comprises water.
- 5. The method of claim 1, wherein said liquid is waste water or sea water.
- 6. An apparatus for measuring the buffering capacity of a liquid comprising:
- (a) a metal working electrode with a pH electrode positioned at or adjacent to a surface of said working electrode;
- (b) at least a first and second electrical circuit, said first electrical circuit comprising means for applying a constant cathodic or anodic potential between said working electrode and a reference electrode, and said second electrical circuit comprising means for measuring the pH at or adjacent to a surface of said working electrode;
- (c) means to create and maintain a constant bulk dissolved oxygen concentration adjacent said working electrode;
- (d) micromanipulator for positioning said pH electrode at or adjacent to a surface of said working electrode; and
- (e) at least a counter electrode and a reference electrode.
- 7. The apparatus according to claim 6, wherein the pH electrode comprises a capillary membrane means, sealed at one end thereof and having said sealed end positioned in a tubular insulating means, said capillary membrane means being fused within said tubular insulating means.
- 8. The apparatus according to claim 7, wherein said capillary membrane means comprises pH sensitive glass and said tubular insulating means comprises lead glass.
- 9. The method of claim 1 wherein said liquid is water and in step (e), said water is continuously aerated to create sufficient bulk dissolved oxygen to be substantially equal to saturation at a given temperature.
Parent Case Info
This application is a continuation of application Ser. No. 07/397,685 filed Aug. 23, 1989.
US Referenced Citations (12)
Non-Patent Literature Citations (1)
Entry |
Lewandowski, et al "Dissolved Oxygen and pH Microelectrode Measurements atater-Immersed Metal Surfaces", Corrosion, vol. 45, No. 2 (Feb. 1989), pp. 92-98. |
Continuations (1)
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Number |
Date |
Country |
Parent |
397685 |
Aug 1989 |
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