Degradation of polyvinyl alcohol (PVA) in neutral conditions based on copper-manganese bimetallic catalyst.

There have been many studies on the degradation of polyvinyl alcohol (PVA) by the Fenton-like method, but the narrow acid-base (pH) range, poor degradation effect, and time-consuming of the Fenton-like method limit its development. Therefore, to improve the shortcomings of the Fenton-like method, the study aimed to synthesize copper-manganese bimetal oxide loaded catalysts (MnCuO@γ-Al₂O₃) through the impregnation calcination method, and its potential to activate hydrogen peroxide (H₂O₂) for the degradation of PVA was evaluated. The X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer Emmett Teller (BET), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) characterizations revealed the chemical composition, structure and morphology of the prepared MnCuO@γ-Al₂O₃, furthermore the synergistic mechanism was proposed. Results indicated that copper and manganese could successfully attach to γ-Al₂O₃ and reduce the specific surface area of γ-Al₂O₃, promoting the transformation of multivalent metals and the generation of oxygen vacancies. In addition, comparative experiments demonstrated that the PVA removal efficiency was significantly improved at the catalyst calcination temperature of 500 °C, reaction temperature of 70 °C, H₂O₂ dosage of 125 mL · L - 1 , and catalyst dosage of 625 mg · L - 1 and more than 96% of PVA was removed within 20 min in neutral conditions. Lastly, four catalyst cycle degradation experiments of PVA were carried out, and the degradation effect could reach more than 96% in a certain time. [ABSTRACT FROM AUTHOR]