Carbazole-Bearing Conjugated Microporous Polymer Electrodes for Uranium Extraction from Seawater with Good Anti-biofouling Feature

Abstract

Emerging electrochemical uranium extraction from seawater offers a promising route for a sustainable fuel supply for nuclear reactor operation. In this work, we intentionally synthesized a conjugated microporous polymer (CMP) with π-conjugated skeletons and permanent porosity, which was induced by in situ electropolymerization on flexible carbon cloths, followed by postdecorating amidoxime groups to create functional materials (CMP-AO). Driven by an extra asymmetrical alternating current electrochemical extraction, the self-supporting and binder-free electrode is exceptionally capable of selectively and rapidly capturing U(VI) from simulated solution, affording an extraction capacity of ∼1806.4 mg/g without saturation. Experimental observation in combination with ex/in situ spectroscopy revealed that CMP-AO enabled surface selective binding sites (amidoxime groups) to U(VI), followed by electrocatalytic reduction (carbazole groups) to yield yellow precipitates (Na₂O(UO₃·H₂O)_x) via reversible electron transfer in the presence of sodium electrolyte. Furthermore, the integrating adsorption-electrocatalysis system achieved an extraction capacity of 18.8 mg/g in real seawater for 21 days and good antibiofouling abilities, validating its feasibility for practical application.