Hierarchically fusiform CuO microstructures decorated with Fe3O4 nanoparticles as novel persulfate activators for 4-aminobenzenesulfonic acid degradation in aqueous solutions

Hierarchically fusiform CuO (hf-CuO) composites decorated with Fe3O4 nanoparticles (NP) were prepared via a two-step method and characterized through X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), nitrogen adsorption–desorption, and energy dispersive X-ray spectroscopy. The catalytic activity of Fe3O4/hf-CuO for 4-aminobenzenesulfonic acid (4-ABS) degradation under different parameters (initial 4-ABS concentration, initial solution pH, PS concentration, and Fe3O4/hf-CuO dosage) was extensively investigated. Results showed that the composite can achieve 94.9% 4-ABS degradation within 240 min. The results of the quenching experiment and electron paramagnetic resonance spectroscopy indicated that SO4·− and ·OH were responsible for 4-ABS degradation. The 4-ABS removal process fitted well with the pseudo-first-order reaction model. The Fe3O4/hf-CuO NPs also exhibited to be reusable and can degrade different organic pollutants such as 2,4-DCP, P-nitrophenol (PNP), and Rhodamine B. The remarkable removal efficiencies of Fe3O4/hf-CuO for different organic pollutants are indicative of the potential applications of Fe/Cu nanocomposites in persulfate activation and the remediation of water contaminated with organic pollutants.