Consequences of the calcination on the morphological, structural, optical, and catalytic properties of CuMgFe-layered double hydroxide for photo-fenton degradation

This study explored the influence of calcination on Layered Double Hydroxides (LDH) applied as catalyst in Fenton and photo-Fenton processes evaluated during sulfamethoxazole (SMX) degradation. According to the findings, CuMgFe-layered double hydroxide underwent significant structural, optical, and catalytic transformations following thermal treatment at 400 °C and 650 °C. X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) analyses showed the formation of pure cuprous delafossites and cupric spinels. The use of the CuMgFe-layered double hydroxide treated at 400 °C and CuMgFe-layered double hydroxide treated at 650 °C in the Fenton process caused an increase in the solution pH, which subsequently inhibited the degradation of SMX, in contrast to LDH without calcination. CuMgFe-layered double hydroxide treated at 400 °C achieved 13 % and 18 % SMX degradation in Fenton and photo-Fenton reaction, while CuMgFe-layered double hydroxide treated at 650 °C resulted in 18 % and 29 %, respectively. Compared to LDH without calcination (26 % and 36 %), the lower degradation values of calcined catalysts were found to be significantly influenced by the pH increase of the suspensions (9.0–9.6). Despite the reduced SMX removal, calcined LDH exhibited intriguing structural and optical modifications, suggesting potential applications beyond degradation processes.