Interface polarization evolution during electroosmosis: An LSV-based in-operando investigation

¹ Coastal and Urban Geotechnical Engineering Research Center, Zhejiang University, Hangzhou, China
² Zhejiang Key Laboratory of the development and utilization of underground space, Hangzhou, China
³ Department of Structural, Geotechnical and Building Engineering, Politecnico di Torino, Torino, Italy

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Interface energy consumption is well recognized as a limitation to the field-scale implementation of electroosmosis (EO). Although interface processes are regarded as crucial, conventional monitoring techniques remain restricted to the measurement of geotechnical parameters and fail to capture the time evolution of the electrode–soil interface during EO. To reveal the underlying mechanisms, linear sweep voltammetry (LSV) was employed to capture the polarization phenomena associated with the interface energy consumption. Specifically, a commonly used one-dimensional apparatus was integrated with a custom-designed LSV detection system, allowing continuous in-operando measurements during EO. The experimentally obtained polarization curves exhibit distinct regions, including an initial linear increase region, an intermediate segmented region, and a plateau region. Such time-dependent segmentation behaviour reflects different states of the electrode–soil interface, developing with the operating time. In particular, the increase in the interface energy consumption is attributed to a gradual transition in the interface conditions, shifting from a stable electrode–soil contact at the early stages to progressively clogged and transport-limited conditions at the later stages. Overall, this study demonstrates that LSV is a valuable tool for the effective monitoring of the electrode–soil interface evolution, and provides an engineering-oriented framework to interpret the interface energy consumption.