Preparation of PdCu Catalyst and the Catalytic Degradation of Methylene Blue and Rhodamine B with PMS

Spherical Cu2O nanoparticles were obtained by reducing copper acetate in N,N-dimethylformamide (DMF) system using glucose as the reducing agent and polyvinylpyrrolidone (PVP) as the surfactant, with which spherical PdCu nanocatalysts were thus synthesized by disproportionation. The catalyst was used for the activation of peroxymonosulfate (PMS) and showed an excellent degradation effect on rhodamine B and methylene blue-contained printing and dyeing wastewater with good stability. Additionally, the surface morphology analysis of the catalyst was carried out by SEM and TEM. The structure was characterized by XRD and FT-IR. The valence state and composition of the catalyst were characterized by XPS. The catalytic performance of the prepared catalysts was investigated with methylene blue and rhodamine B used as target pollutants. The results showed that the catalytic reduction efficiency of PdCu nanocatalyst for the two pollutants could reach 99% at 20 °C, when catalyst concentration was 60 mg/L and PMS concentration was 1.0 g/L and 0.6 g/L, respectively. The degradation efficiency of the catalyst was significantly reduced when Cl−,HCO3−and HA were present in the water. The degradation efficiency was above 90% when the pH was in the range of 5–11. The excellent performance of the PdCu/PMS system in the treatment of RhB-contained wastewater was further confirmed by taking into account of the data of free radical quenching experiment and the results of electron paramagnetic resonance (EPR) experiment. After three cycles, the removal rate of MB and RhB could still be maintained at more than 90%, which proved its excellent recyclability due to its remarkable stability and efficiency.