Photocatalytic removal of 17β-estradiol from water using a novel bimetallic NiCu/NbO catalyst.

The development of effective photocatalytic materials is essential for removing emerging pollutants from aqueous media, such as the hormone 17β-estradiol (E2). In this study, a novel photocatalyst based on niobium pentoxide (NbO) functionalized with nickel (Ni) and copper (Cu) was synthesized for E2 removal. The NiCu/NbO photocatalyst was prepared using a facile wet impregnation method and characterized by various techniques. The incorporation of Ni and Cu into NbO reduced the band gap energy from 3.3 to 2.8 eV, enabling efficient utilization of visible light. Moreover, NiCu/NbO exhibited the highest E2 removal efficiency (82%) under UV-A-assisted conditions at a concentration of 1.5 g L. The reaction kinetics were found to follow a second-order model with a rate constant of k = 0.0020 L g min, and a plausible reaction mechanism was proposed. Through the study of radical elimination, it was proven that the radical oxidation reaction mechanism predominated in the reaction. The results of the toxicity assays, combined with the TOC parameter, demonstrated the efficacy of photocatalytic degradation in reducing E2. These findings demonstrate the great potential of the NiCu/NbO photocatalyst for removing persistent pollutants.