Featured Research

from universities, journals, and other organizations

pH measurements: How to see the real face of electrochemistry and corrosion?

Date:
December 18, 2012
Source:
Institute of Physical Chemistry of the Polish Academy of Sciences
Summary:
For several decades antimony electrodes have been used to measure the acidity/basicity -- and so to determine the pH value. Unfortunately, they allow for measuring pH changes of solutions only at a certain distance from electrodes or corroding metals. Researchers have now developed a method for producing antimony microelectrodes that allow for measuring pH changes just over the metal surface, at which chemical reactions take place.

Antimony microelectrodes for pH measurement at metal surfaces, developed at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw, will assist in a better understanding of the nature of electrochemical and corrosion processes. The picture shows Dr Iwona Flis-Kabulska.
Credit: IPC PAS, Grzegorz Krzyżewski

For several decades antimony electrodes have been used to measure the acidity/basicity -- and so to determine the pH value. Unfortunately, they allow for measuring pH changes of solutions only at a certain distance from electrodes or corroding metals. Researchers at the Institute of Physical Chemistry of the Polish Academy of Sciences developed a method for producing antimony microelectrodes that allow for measuring pH changes just over the metal surface, at which chemical reactions take place.

Changes in solution acidity/basicity provide important information on the nature of chemical reactions occurring at metal surfaces. These data are particularly important for a better understanding of electrochemical and corrosion processes. Unfortunately, the measurement methods used to date in the research laboratories did not allow for observing the changes with sufficient precision.

The information on basicity or acidity is contained in the well-known and commonly used pH value. pH for pure (inert) water is equal to 7, for hydrochloric acid -- 0, and for sodium hydroxide (one of the strongest bases) -- 14.

"Until now we have not been able to measure pH changes at places where the most interesting things occur: at the very metal surface. The measurements had to be carried out at a certain distance, in the electrolyte bulk, as we call it. It's obvious that the data collected under such circumstances not always accurately and not always immediately reflected what was really going on at the metal surface," says Dr Iwona Flis-Kabulska from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw.

In an attempt to better understand the mechanisms governing the electrochemistry and corrosion of metal surfaces, researchers from the IPC PAS developed a new measurement tool. It is an antimony microelectrode with a design allowing for performing easy and reproducible measurements just over the metal surface -- at a distance of one tenth of a millimeter only. A patent application for the device was filed.

The new microelectrode is made of a glass capillary filled with liquid antimony. Stretched to reduce the cross section and cut flat, the microelectrode enables carrying out measurements at hard surfaces, in a liquid environment. It is thus suitable for monitoring electrochemical reactions and corrosion processes resulting from interaction between metal and solution or a thin water film.

A good point of the microelectrode developed at the IPC PAS is that the measurements can be easily performed. The designs available earlier on the market required, i.a., the use of micromanipulators for precise placement of electrodes at the surface. "We make use of ordinary geometry. We just move a flat cut glass microelectrode tip closer to the surface of the tested metal, at an appropriate angle. We know the tip diameter and the angle, at which it has been moved closer to the surface, so we know immediately how it is tilted to the surface, and therefore what is the distance between the metal and the antimony core inside the electrode," says Dr Flis-Kabulska.

During measurements, the flat microelectrode tip is tilted to the surface of the tested metal, which means that it does not contact the metal surface with its entire surface. This fact provides additional benefits. Protons produced in reactions on the surface do not disperse quickly in the solution. Their diffusion is slowed down, and it significantly increases the instrument sensitivity and the accuracy of measurements.

The antimony microelectrode from the IPC PAS shows the highest sensitivity in measurements of pH changes ranging from 3 to 10.

The application potential of the new microelectrode is broad. The instrument was constructed with applications in the laboratory research in mind. Due to low manufacturing cost, simplicity and reproducibility of measurements, as well as high sensitivity to changes, the microelectrode could be also used in field tests, for instance as a component of sensors monitoring the condition of reinforced concrete structures.


Story Source:

The above story is based on materials provided by Institute of Physical Chemistry of the Polish Academy of Sciences. Note: Materials may be edited for content and length.


Cite This Page:

Institute of Physical Chemistry of the Polish Academy of Sciences. "pH measurements: How to see the real face of electrochemistry and corrosion?." ScienceDaily. ScienceDaily, 18 December 2012. <www.sciencedaily.com/releases/2012/12/121218081828.htm>.
Institute of Physical Chemistry of the Polish Academy of Sciences. (2012, December 18). pH measurements: How to see the real face of electrochemistry and corrosion?. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2012/12/121218081828.htm
Institute of Physical Chemistry of the Polish Academy of Sciences. "pH measurements: How to see the real face of electrochemistry and corrosion?." ScienceDaily. www.sciencedaily.com/releases/2012/12/121218081828.htm (accessed October 1, 2014).

Share This



More Matter & Energy News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

US Police Put Body Cameras to the Test

US Police Put Body Cameras to the Test

AFP (Oct. 1, 2014) Police body cameras are gradually being rolled out across the US, with interest surging after the fatal police shooting in August of an unarmed black teenager. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com
Raw: Japan Celebrates 'bullet Train' Anniversary

Raw: Japan Celebrates 'bullet Train' Anniversary

AP (Oct. 1, 2014) A ceremony marking 50 years since Japan launched its Shinkansen bullet train was held on Wednesday in Tokyo. The latest model can travel from Tokyo to Osaka, a distance of 319 miles, in two hours and 25 minutes. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Robotic Hair Restoration

Robotic Hair Restoration

Ivanhoe (Oct. 1, 2014) A new robotic procedure is changing the way we transplant hair. The ARTAS robot leaves no linear scarring and provides more natural results. Video provided by Ivanhoe
Powered by NewsLook.com
Argentina's Tax Evaders Detected, Hunted Down by Drones

Argentina's Tax Evaders Detected, Hunted Down by Drones

AFP (Sep. 30, 2014) Argentina doesn't only have Lionel Messi the footballer, it has now also acquired "Mesi" the drone system which monitors undeclared mansions, swimming pools and soy fields to curb tax evasion in the country. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins