What is the difference between Sodium and Potassium Permanganate?

Introduction

Permanganate is a powerful oxidant which chemically reduces chlorinated ethene compounds quickly and effectively without forming daughter products such as dichloroethene and vinyl chloride.  It can be provided as sodium and potassium salt. Both versions are equally as effective if in the same molar quantities.  However, because sodium permanganate is more soluble (40% vs. 5%), it is easier to use and more flexible.  Potassium permanganate is typically more economical and because it cannot be made into a very concentrated solution can be safer.

Chemistry

Sodium and Potassium permanganate dissociates in aqueous solution:

KMnO4 → K+ + MnO4–

NaMnO4 → Na+ + MnO4-

Permanganate ions oxidize the organic contaminant PCE and TCE:

PCE: C2Cl4 + 2MnO4- → 2CO2 + 2MnO2 (s) + Cl2 + 2Cl-

TCE: C2Cl3H + 2MnO4- → 2CO2 + 2MnO2 (s) + 3Cl- + H+

From these equations, it takes two moles of the permanganate to oxidize one mole of the contaminants PCE and TCE. The reaction of permanganate is described by second order reaction kinetics. The rate of reaction is dependent upon the concentrations of both the permanganate and the COC as well as the concentrations of other competing species such as, reduced metals and natural organic matter. Hence, increasing the concentration of permanganate will increase the rate of reaction with the COCs and other competing species.

Applications

Permanganate is easily applied to most sites. The application method is determined by the geological characteristics of the site, type and concentration of contaminates, and potential physical limitations of the working space. Permanganate is only effective with dissolved phase contaminates in the saturated zone. Successful applications are dependent on achieving contact of the oxidant with the contaminated in the time where the oxidant is active. Permanganate is typically active for a few weeks to a few months depending on site conditions.

  • Gravity Flow or Drip Application
  • DPT Injection
  • Pneumatic and Hydraulic Fracturing.
  • Soil Mixing

Logistics

Hepure has relationships with product distributors positioned throughout the United States, allowing us to provide competitive shipping rates. Typical packaging for 40% sodium permanganate is in drums, totes, or tankers.  Potassium permanganate can be provided in pails or drums.  In addition to the standard packaging, our relationships with chemical blenders provide our clients with the opportunity to receive chemicals made to order and ready to inject at the desired concentration.