Nanoarchitecturing of CuFeLa layered double hydroxide on graphite felt for photo-electrocatalytic degradation of emerging pollutants

Abstract

Due to the importance of wastewater decontamination from emerging pollutants, various approaches have been established as treatment processes. In the present study, a graphite felt (GF) electrode was modified with a layered double hydroxide (LDH) to degrade rifampicin in a combined photo-electrocatalytic process. The synthesized CuFeLa LDH was deposited on the GF (CuFeLa LDH@GF) via the electrophoretic deposition method. SEM images showed the uniform coverage of GF fibers by two-dimensional flake-like LDH nanoparticles. The CuFeLa LDH coating improved the electron transfer kinetics of GF and reduced charge transfer resistance. The photo-electrocatalytic process employing the CuFeLa LDH@GF cathode could achieve 79.4% and 65.7% degradation efficiency for rifampicin at pH 6 and 8, respectively. The apparent reaction rate constant (kapp) of the process with CuFeLa@GF (photo-electrocatalysis) was 7.98 times that of the raw GF electrode (photo-electrolysis). This was due to the increased production of hydroxyl radicals (center dot OH), which was shown by radical scavenging and center dot OH trapping experiments. Moreover, the coated electrode had a high stability with only a 4.7% performance loss in 5 successive application tests. The liquid chromatography-mass spectrometry (LC-MS/MS) analysis revealed the intermediates produced during the degradation process. The CuFeLa LDH@GF, with its consistent performance under nearly neutral conditions and catalytic activity over extended periods, indicates potential for effective and environmentally friendly approaches to wastewater treatment.