Enhanced reactive oxygen species via in situ producing H2O2 and synchronous catalytic conversion at stable modified copper foam cathode for efficient high-concentration organic wastewater treatment and simultaneous electricity generation

Application of iron-intercalated graphite for modification of nickel foam cathode in heterogeneous electro-Fenton system: Bisphenol A removal from water at neutral pH

The presence of bisphenol A (BPA) in natural waters can be highly harmful due to its high persistence and adverse effects, raising concerns to remove this hazardous compound. Herein, an electro-Fenton system is proposed to eliminate BPA, wherein the iron source in the Fenton reaction is provided by its intercalation into the carbon layers of graphite. The produced heterogeneous catalyst was then coated onto the nickel foam serving as a cathode. The magnetic graphite intercalated compound (mGIC) and the modified cathode (before and after experiments) were characterized by FE-SEM, EDX, XPS, and XRD analyses. Some effective parameters, namely pH (3-9), current density (0-20 mA cm-2), and BPA concentration (0.5-20 mg L-1) were studied. At pH 3, the removal of BPA was 95.52%, and under neutral circumstances, the BPA and TOC removals were 85.70 and 58.12%, respectively at the initial BPA concentration of 10 mg L-1. The proposed system was also applied to several water sources spiked with BPA at the concentration of 5 mg L-1 under neutral pH, which exhibited considerable removal of 99.74%, 99.72%, and 92.70% for groundwater, municipal effluent wastewater, and tap water, respectively. The proposed system was applied for 15 consecutive cycles without showing significant changes in BPA removal, indicating its excellent stability and reusability. Furthermore, based on the analysis of intermediates, a possible decomposition pathway was proposed, indicating a reduction in overall toxicity. By using the proposed heterogeneous electro-Fenton system, iron waste is avoided, and operational costs of treatment can be reduced due to the absence of iron sludge production and catalyst loss.

Flower ball cathode assembled from Cu doped Co3S4/Ni3S2 ultrathin nanosheets in a photocatalytic fuel cell for efficient photoelectrochemical rifampicin purification and simultaneous electricity generation based on a CuO QDs/TiO2/WO3 photoanode

Herein, an efficient CuO QDs/TiO₂/WO₃ photoanode and a Cu doped Co₃S₄/Ni₃S₂ cathode were successfully synthesized. The optimized CuO QDs/TiO₂/WO₃ photoanode achieved a photocurrent density of 1.93 mA cm^-2 at 1.23 vs. RHE, which was 2.27 times that of a WO₃ photoanode. The CuO QDs/TiO₂/WO₃-buried junction silicon (BJS) photoanode was coupled with the Cu doped Co₃S₄/Ni₃S₂ cathode to construct a novel photocatalytic fuel cell (PFC) system. The as-established PFC system showed a high rifampicin (RFP) removal ratio of 93.4% after 90 min and maximum power output of 0.50 mW cm^-2. Quenching tests and EPR spectra demonstrated that ˙OH, ˙O₂^- and ¹O₂ were the main reactive oxygen species in the system. This work provides a possibility to construct a more efficient PFC system for environmental protection and energy recovery in the future.