Electrochemically enhanced adsorption of perfluorooctanoic acid (PFOA) on CuO-CNTs composite electrodes

With the intensification of the global freshwater crisis, seawater desalination has emerged as a vital approach for obtaining freshwater resources. However, the presence of persistent pollutants in seawater poses new challenges to the desalination process. Among these, perfluorooctanoic acid (PFOA) has garnered significant attention due to its stability, bioaccumulative nature, and potential toxicity. While multi-walled carbon nanotubes (CNTs) exhibit high adsorption capacity, their effectiveness in PFOA removal remains limited. To address this, we synthesized copper oxide-modified CNTs (CuO-CNTs) and fabricated electrodes using a straightforward coating technique for electrochemically assisted PFOA adsorption. Our results demonstrate that CuO-CNTs electrodes achieved a 1.26-fold increase in the initial electrosorption rate and a 2.04-fold improvement in removal efficiency, reaching 89.25 % at 0.6 V compared to CNTs. The maximum electrosorption capacity also increased 1.69-fold at 0.6 V relative to 0 V. Furthermore, studies on adsorption mechanism and various ion strengths/ ion types/ pH provide important references for optimizing electrosorption technology in desalination. These findings contribute to improving the efficiency and effectiveness of contaminant removal during desalination, thereby enhancing the quality of desalinated water. • CuO-CNTs electrodes achieved an 89.25 % PFOA removal efficiency at a 0.6 V bias. • Electrosorption capacity of CuO-CNTs electrodes increased 1.69-fold compared to CNTs alone. • CuO-CNTs electrodes demonstrated effective reusability and regeneration for long-term applications. • Ionic strength, ion species, and pH significantly influence PFOA electrosorption efficiency. • A cost-effective and energy-efficient solution for PFOA removal under mild operating conditions.