Shell-Fe/ZnO: A recyclable catalyst with Fe-doped ZnO shell structure for photocatalytic oxidative degradation of tetracycline hydrochloride

In this work, a solvothermal approach was employed to load Fe and Zn elements onto processed diatom frustules, and Shell-Fe/ZnO composite photocatalyst was prepared through high-temperature annealing. The prepared Shell-Fe/ZnO composite demonstrated a degradation efficiency of 96.56 % towards TC-HCl within 120 min. Shell-Fe/ZnO was characterized using TGA, XRD, SEM, EDS. TEM, XPS and UV–vis DRS. Furthermore, the study also explored potential influencing factors such as pH, TC-HCl concentration and catalyst dosage. The results indicated that Shell-Fe/ZnO composite exhibits remarkable structural stability and reproducibility in practical applications. Burst experiments demonstrated that both components O2- and h+ contributed to the decomposition of TC-HCl. The verification of burst experimental results was supported by TOC testing and first-order kinetic modeling. The renewable nature of diatom frustules and the ferromagnetic properties of Fe reduced the production and usage costs of the catalyst, paving the way for the development of sustainable, highly efficient, and recyclable catalysts, thereby providing a novel direction for the photochemical degradation of TC-HCl.