Dice Question Streamline Icon: https://streamlinehq.com

Mechanism of surfactant-induced conductivity loss in activated carbon slurries

Elucidate the physicochemical mechanism responsible for the change in electrical behavior of YP-50 activated carbon slurry electrodes (10% w/w in 1 M H2SO4 containing 0.55 M Fe2SO4) when Triton X-100 is added at α = 0.7, specifically the near-complete loss of conductivity coincident with the loss of gel-like rheology.

Information Square Streamline Icon: https://streamlinehq.com

Background

The paper measures the conductivity of an activated carbon (AC) slurry electrode under flow, showing values of 3–4 mS/cm without surfactant and a drop to 0.25–0.35 mS/cm at surfactant saturation (α = 0.7), close to the electrolyte conductivity, indicating the AC contribution is eliminated.

This loss of electrical conductivity occurs at the same surfactant ratio where the rheology transitions from gel-like to fluid-like, suggesting disruption of both mechanical and electrical percolation. The authors state that further work is needed to fully understand the change in electrical behavior upon surfactant addition.

References

While further work will be needed to fully understand this change in the electrical behavior of these particles with addition of surfactants, it is interesting to see that the contribution of AC particles to the overall conductivity also diminishes at the same surfactant ratio at which we observe the loss of gel-like behavior.

— Surfactant-Driven Dynamic Changes in Rheology of Activated Carbon Slurry Electrodes (2403.13782 - Das et al., 20 Mar 2024) in Section 3.7 (Slurry conductivity)