What is pE?

If you’ve never heard of pE, you might just think that it has something to do with pH. This is true to some extent, the determination of pE involves pH but besides that, they are quite different. pH is a representation of the concentration of H+ ions in a solution while pE is the measurement of a systems’ capacity to oxidize or reduce. In aqueous solutions, pE is the measurement of the solution’s tendency to gain or lose electrons when subjected to a new chemical species.

Why is pE important?

Science Direct states:

“Redox potential measurements allow for rapid characterization of the degree of reduction and for predicting stability of various compounds that regulate nutrients and metal availability in soil and sediment. Redox potential is diagnostic for determining whether an area is functioning as wetland or nonwetland.”

In environmental chemistry, the use of pE is used to determine the oxidizing and reducing conditions in soil and/or water. By comparing the pE values of aerated surface water, rivers, lakes, oceans, rainwater, or other water bodies to the pE values of various redox reactions, the direction of a redox reaction can be determined. With the reaction direction, the impact of certain chemical species in a body of water can be ascertained.

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/redox-potential

https://en.wikipedia.org/wiki/Reduction_potential