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

Abstract

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 [Formula: see text], and catalyst dosage of 625 [Formula: see text]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.