In this study, four different ZVI/M-PMS systems (e.g., ZVI/Cu, ZVI/Co, ZVI/Ni and ZVI/Ag) were fabricated to investigate the removal of contaminants (Rhodamine B (RB), 2,4-dichlorophenol (2,4-DCP), bisphenol A (BPA), bisphenol F (BPF), levofloxacin (LFX), and chloramphenicol (CAP)). The results indicated that ZVI/Cu and ZVI/Ag exhibited a superior performance to activate PMS compared with the ZVI. The mechanism of the investigation showed that a relatively positive correlation between the release of iron ions (Fe²⁺) and contaminant removal efficiency was found in different ZVI/M-PMS systems. This revealed that galvanic couples affected iron corrosion, and the ZVI/Cu and ZVI/Ag bimetallic systems facilitated the corrosion of ZVI but the ZVI/Co and ZVI/Ni bimetallic systems restrained the corrosion of ZVI. The electron paramagnetic resonance (EPR) analysis and the radical quenching experiments apparently supported the roles of the hydroxyl radical (˙OH), sulfate radical (SO₄˙⁻) and superoxide radicals (O₂˙⁻), which suggest that these reactive radicals were primarily responsible for the degradative route, and the contribution rate may follow the order of SO₄˙⁻ < O₂˙⁻ < ˙OH. Furthermore, investigation of crucial parameters showed that the contaminant removal ratio increased with an increase in the metal ratio (M : ZVI) to a certain limit, and a higher bimetal catalyst dosage and extremely acidic conditions (except for ZVI/Co, which showed the best catalytic performance under neutral condition) enhanced the degradation of contaminants. In the evaluation of real water samples, there was almost no influence from the water matrices compared to the control condition, and the ZVI/Cu and ZVI/Ag bimetallic particles showed great potential to treat various wastewater. Therefore, this study helps to understand the application of oxidation process based on bimetallic particles.

Magnetic Co-doped Fe ₃ O ₄ @FeOOH nanocomposites were prepared in one step using the hydrothermal synthesis process for catalyzing peroxymonosulfate (PMS) to degrade refractory methylene blue (MB) at a wide pH range (3.0–10.0).

The aging behavior of microplastics (MPs) in the environment has garnered significant attention, yet the exact aging process undergone by microplastics during advanced oxidation still remains unclear. This study emphasized elucidating the oxidation and dechlorination mechanisms of polyvinyl chloride microplastics (PVC MPs) within the UV-activated sodium percarbonate system (UV/SPC). After 35 h of UV/SPC (0.05 M) treatment, it exhibited effective dechlorination with a Cl⁻ release of 100.62 ± 13.17 mg/L. And this treatment resulted in the fragmentation and release of fragments from the PVC MPs, thereby contributing to their further aging and dechlorination. In addition, an increase in oxygen-containing functional groups was identified. Quenching experiments confirm that $·\mathrm{O}\mathrm{H}$ and ${·\mathrm{C}\mathrm{O}}_3^{-}$ are the primary active species present in the system. In summary, the aging of PVC MPs results in a process of fragmentation, releasing fragments that are more fragile and susceptible to mineralization compared to the original PVC MPs. The release of chloride ions originates from the mineralization of these fragments released from PVC MPs by $·\mathrm{O}\mathrm{H}$ and ${·\mathrm{C}\mathrm{O}}_3^{-}$. This study has provided valuable insights into the aging mechanisms of MPs in practical wastewater treatment.