One-step hydrothermal preparation of WO3-carbon felt for electrolytic recovery of copper from PCB wastewater.

Recovering copper from printed circuit board (PCB) wastewater remains challenging due to complex coexisting ions and high organic content. Here, a WO3-carbon felt electrode was fabricated through a one-step hydrothermal method followed by binder-free spray coating, producing a sea-urchin/plate-like WO3 morphology with strong adhesion and high electrochemical activity. The WO3-carbon felt electrode achieved a 70.1% copper removal efficiency at 1.2 V, outperforming unmodified carbon felt due to enhanced surface area, reduced charge-transfer resistance, and improved electrocatalytic kinetics. Orthogonal optimization identified voltage and pH as the dominant factors affecting performance. The electrode also maintained stable efficiency in actual PCB wastewater with high COD, demonstrating strong anti-interference capability. Cost analysis demonstrated that the WO3-carbon felt electrode exhibited a markedly lower unit-area cost (24.8 USD m-2) than graphite or Sn-Sb/Ti electrodes, confirming its economic feasibility. This study highlights a facile, scalable strategy for developing oxide-carbon composite electrodes with promising application potential in metal recovery and industrial wastewater treatment.