Facile fabrication of Cu/Al LDH-Camellia sinensis extract composite for enhanced visible-light-driven photocatalytic degradation of ceftriaxone with mechanistic insights

The removal of the antibiotic ceftriaxone (CEF), which is known to be persistent and difficult to degrade in aquatic environments, is a significant challenge in wastewater treatment. This research focuses on the synthesis, characterization, and evaluation of the photocatalytic performance of copper-aluminum layered double hydroxide (Cu/Al LDH) composites modified with the addition of Camellia sinensis extract (CSe) for the photodegradation of CEF. The Cu/Al-CSe catalyst was synthesized via the coprecipitation method and characterized using various analytical techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) surface area analysis, UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS), and scanning transmission electron microscopy (STEM). Under optimal conditions, Cu/Al-CSe exhibited superior photocatalytic performance, achieving a CEF removal efficiency of 86% under visible-light irradiation, compared with 75.81% for pristine Cu/Al LDH after 60 min. The enhanced activity is attributed to improved charge separation and suppressed electron-hole recombination, promoted by phytochemical components from CSe. The regeneration test of the Cu/Al-CSe catalyst was conducted thru five consecutive CEF degradation cycles, and the results showed a decrease of 14.63%, indicating no significant degradation occurred. This proves that Cu/Al-CSe has good stability and high potential for practical applications. Additionally, the results of the radical scavenging experiments indicate that holes ( h + ) significantly contributes to the photodegradation reaction, followed by superoxide radicals (•O 2 - ), hydroxyl radicals (•OH), and electrons ( e - ). Overall, these findings demonstrate that Cu/Al-CSe is a promising photocatalyst for CEF removal in wastewater treatment.