CuCe-LDHs anchored on CNTs-COOH/copper foam cathode for the electrocatalytic degradation of sulfamethoxazole under near-neutral conditions

Environmental contamination with antibiotics has become a global crisis. Heterogeneous electro-Fenton (EF) technology is a highly efficient approach to remove antibiotics from wastewater. In this study, CuCe-layered double hydroxide (LDH) particles were fixed on the carboxylated carbon nanotubes (CNTs-COOH) and then doped on foamed copper electrodes (CuCe-LDHs/CNTs-COOH/CF). The CuCe-LDHs/CNTs-COOH/CF electrode was used as the cathode for sulfamethoxazole (SMX) degradation in the heterogeneous EF procedure. The coexistence of CeIII/CeIV and CuI/CuII redox couples led to significant enhancement in the interfacial electron transfer, accelerated the in situ formation and decomposition of H2O2, and promoted the formation of O-center dot(2)- and (OH)-O-center dot active free radicals. The electrode demonstrated good stability, low metal-ion leaching, and a wide pH application range. The results show that within 90 min almost 100.0% of SMX ([SMX] = 10 mg L-1) was degraded. After ten cycles, the electrode retained high stability and outstanding catalytic capacity. Finally, the probable paths of SMX degradation in the heterogeneous EF procedure were proposed, and the biotoxicity of SMX and its decomposition products during degradation was systematically evaluated. This study can supply meaningful ideas for designing and synthesizing efficient and stable cathodes for removing antibiotics from wastewater via using the in the heterogeneous EF reaction system.

Automated summary

In this study, a highly efficient and stable cathode for removing antibiotics from wastewater was designed by fixing CuCe-layered double hydroxide particles on carboxylated carbon nanotubes. The electrode showed excellent performance in degrading sulfamethoxazole in the heterogeneous electro-Fenton process, with high stability and catalytic capacity.