Facile in-situ electrosynthesis of a novel PEDOT derivative for efficient uranium electroextraction

Abstract

Electroextraction is one of the most efficient methods for recovering uranium from seawater. However, electrodes, as key components of uranium electroextraction, still face significant challenges such as complex fabrication and balancing high electron transfer ability with specific binding site functionality, which significantly hinder their practical applications in this field. In this work, a novel free-standing electrode is constructed via in-situ electrosynthesis of a carboxyl-functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) derivative onto flexible carbon cloth substrate, offering facile fabrication process and providing numerous selective adsorption sites. Under the action of an alternating electric field, the resultant electrode exhibits high selectivity for uranium (K_d(U) ≈ 2.05 × 10⁶ mL g⁻¹), excellent removal efficiency of 91% after ten cycles and high extraction capacity of 1670 mg g⁻¹, as well as a remarkable extraction rate of 0.42 mg g⁻¹ d⁻¹ in natural seawater, superior to most state-of-the-art electrodes. Furthermore, the electroextraction mechanism involves the capture of uranyl ions by carboxyl groups and their subsequent transformation into Na₂O(UO₃·H₂O)_x precipitates in the presence of Na⁺. This electrode is expected to achieve a breakthrough in performance within the field of uranium electroextraction and serve as an effective tool for practical applications in natural seawater.