Reusable Laser-Induced Graphene Catalytic Filters for Pollutant Removal

Laser-induced graphene (LIG) surfaces have attracted significant interest for desalination and water treatment due to their simple, scalable, and reagent-free fabrication process. While incorporating metal oxide catalysts enhances contaminant removal, conventional methods involve harsh conditions and toxic chemicals and catalytic activity may decline over time. To address these challenges, we present a simple electroloading approach for fabricating LIG-based catalytic filters. The influence of the deposition mode, applied voltage, and loading time was systematically studied, and optimized conditions were used to load iron, zinc, and copper oxides onto LIG filters. The LIG-based catalytic filters, characterized by surface and electrochemical techniques, exhibited electrochemical responses 2–8 times higher than those of the control filters. They achieved twice the methylene blue (MB) removal (∼50%) in the presence of H 2 O 2 compared to its absence (∼20%) and nearly 100% MB removal at 3 V compared to approximately 20% at 0 V. In cross-flow mode, the catalytic filters achieved ∼100% MB removal compared to 60% with the control. In situ catalyst electroloading was also successfully demonstrated, resulting in excellent ciprofloxacin removal. The catalytic filters also achieved ∼80% removal of BPA, proving their effectiveness in removing nondye and nonantibiotic organic pollutants as well. Stability tests indicated that the catalytic filters exhibit excellent stability and reusability. Furthermore, the method can help reload the catalysts on the exhausted catalytic surfaces. The facile, scalable fabrication of LIG-based catalytic filters coupled with the ability to load/reload catalysts onto exhausted filters can extend the lifespan of catalytic filters, support environmental remediation, and hold great significance for other applications requiring metal oxide-based surfaces, including MFCs, photocatalysis, sensing, and energy storage.