Fabrication of polyaniline-modified CNT/CS carbon aerogel composite electrode and its electrosorption performance of uranium

Electrosorption technology has garnered significant attention in the field of U(VI) recovery due to its advantages such as low energy consumption, environmental friendliness, and easy regeneration. However, its application remains limited by challenges including insufficient active sites in electrode materials, poor surface wettability, and inherent ion rejection effects. In this study, carbon nanotubes were incorporated into a chitosan solution to successfully prepare carbon aerogel. By electrodepositing polyaniline at different concentrations, a novel carbon nanotube/chitosan/polyaniline composite electrode (CCP) was developed. The CCP electrode exhibits a stable three-dimensional porous structure, high specific capacitance, excellent hydrophilicity, and outstanding charge–discharge stability. The experimental results demonstrate that the electrosorption behavior of U(VI) on the CCP electrode is influenced by both applied voltage and solution pH. The kinetic process follows the pseudo-first-order model, while the adsorption isotherm conforms to the Langmuir model. Under optimal conditions (0.9 V, pH 4.5), the CCP-2 electrode achieves a maximum U(VI) electrosorption capacity of 344.8 mg/g. Systematic charge–discharge cycling tests demonstrated that the CCP-2 electrode maintained over 85 % of its adsorption capacity after 7 cycles, exhibiting excellent cycling stability. Further investigation revealed that the outstanding U(VI) electrosorption performance of CCP-2 electrode originated from the synergistic effects of electric double-layer capacitance and pseudocapacitance. Moreover, the abundant NH, NH⁺ and OH functional groups on the electrode surface provided numerous active sites. The interactions and synergistic effects among these groups significantly enhanced the uranium adsorption capacity. This study provides a novel solution for efficient U(VI) removal from uranium-containing wastewater.