What Is Redox Potential?

The redox potential ^[1] is used to reflect the macroscopic redox properties exhibited by all substances in the aqueous solution. The higher the redox potential, the stronger the oxidizing ability, and the lower the redox potential, the stronger the reducing ability. A positive potential indicates that the solution exhibits a certain degree of oxidization, and a negative potential indicates that the solution exhibits a certain amount of reducing ability.

Redox potential For a water body, there are often multiple redox couples, which constitute a complex redox system, and its redox potential is the comprehensive result of redox reactions between various oxidants and reducing substances

For a water body, there are often multiple redox potentials, which constitute a complex redox system. And its redox potential is the comprehensive result of redox reactions between various oxidizing substances and reducing substances ^[1]

A platinum electrode is used as an indicator electrode, a saturated calomel electrode is used as a reference electrode, and a water sample is used to form a primary battery. The redox potential of the platinum electrode relative to the saturated calomel electrode was measured with an electronic millivoltmeter or a universal pH meter, and then the redox potential of the composition relative to the standard hydrogen electrode was used as the report result.

Calculation formula: n = ind + ref

In the formula:

n redox potential of measured water sample, mV;

ind-measured redox potential of water sample, mV;

ref Measure the electrode potential of saturated calomel electrode at temperature, mV, which can be found in the Handbook of Physical Chemistry.

In fact, especially for most biological systems, without the addition of enzymes and electron carriers, no recognizable reaction occurs. In addition to directly measuring the redox potential, the redox potential can also be used according to the calculation of the equilibrium constant.

The redox potential of water must be measured on site.

The redox potential is affected by factors such as solution temperature, pH, and reversibility of chemical reactions.

The redox potential is related to the oxygen partial pressure and is also affected by pH. When the pH is low, the redox potential is high: When the pH is high, the redox potential is low ^[3] .