Enhanced cesium removal from clay minerals using surfactant-assisted capacitive deionization

Summary

Cesium-contaminated clays are particularly difficult to remediate because Cs⁺ can become strongly trapped within the interlayers of clay minerals. In this work, we developed a surfactant-assisted electrochemical approach that combines clay interlayer modification with capacitive deionization.

The surfactant expands and alters the clay interlayers, helping release otherwise strongly retained Cs⁺, while an applied electric field drives the liberated ions toward porous carbon electrodes. By coupling these two mechanisms, substantially greater Cs removal was achieved than with surfactant treatment alone.

Beyond cesium remediation, the work demonstrates a broader strategy for extracting ions from layered minerals by combining chemical control of interlayer accessibility with electrochemical separation.

Key findings

• CDI–surfactant coupling removes >90% of Cs from clays within 1 h, including fully saturated montmorillonite
• Electric-field-driven ion migration accelerates desorption of interlayer-bound Cs⁺
• Up to 50% less surfactant needed without loss of removal efficiency