Application of nickel foam supported Cu–MnO2 in microwave enhanced Fenton-like process for p-nitrophenol removal: Degradation, synergy and mechanism insight

Diatomic metals catalysts (DAMCs) have attracted researchers' attention in Fenton-like reactions for persistent organic pollutants elimination. A novel composite of Cu–MnO2 loaded on the nickel foam (Cu–MnO2/NF) was synthesized and creatively combined with a microwave (MW) enhanced Fenton-like system—promoting the p-nitrophenol (PNP) removal efficiency to 92.4% within 10 min. The synergistic effect (ξ) between Cu–MnO2/NF and power-control MW-Fenton-like process was up to 11.69 ≫ 0, and the non-thermal result significantly contributed. The participation of Cu–MnO2/NF significantly increased the system's energy efficiency from 3.58 mg·kWh−1 to 44.35 mg·kWh−1. Different from specific degradation, the system maintained high removal efficiency with various pollutants (methylene blue (MB), rhodamine B (RhB), bisphenol A (BPA), and diclofenac sodium (DCF)). The stability of CuMnO2/NF was verified via the recovery experiment, and the applicability of the MW-Fenton-like system has been confirmed. The PNP degradation mechanism was systematically discovered by electron paramagnetic resonance (EPR) detection and radical scavenging experiments. Multiple active species (HO•, e−, O2•-, h+, and 1O2) were generated on the Cu–MnO2/NF surface via electronic transfer and the selective absorption of microwaves. Overall, this study proposes a new possibility in the MW-Fenton-like technology investigation.