Smart nanostructured electrodes integrated with microbial fuel cells for wastewater-to-energy conversion and on-site detection of antibiotic in real wastewater.

Detection of ciprofloxacin (CIP) is crucial due to its persistence and frequent occurrence in water bodies. An algal microbial fuel cell (MFC) integrated with an electrospun carbon nanotube-polyaniline-zinc oxide (CNT-PANI-ZnO) nanofiber electrode was developed for simultaneous renewable energy generation and CIP detection. The electrode enhanced electron transfer efficiency, enabling sensitive monitoring of voltage changes during CIP analysis. The electrode properties were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis) spectroscopy, zeta potential, and contact angle analyses. Bio-electrochemical performance was assessed using linear sweep voltammetry (LSV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The algal MFC achieved a maximum power density of 27.57 ± 0.95 mW m-3 at a current density of 46.73 ± 0.57 mA m-2 with an internal resistance of 22 Ω. CIP was detected with a minimum limit of 0.5 μg L-1 and a sensitivity of 0.1568 mV (μg L-1)-1 under stable voltage conditions. The system exhibited reusability over three operational cycles. These findings demonstrate the potential of CNT-PANI-ZnO-based algal MFCs as eco-friendly platforms for sustainable energy conversion and real-time contaminant sensing.