Urea Hydrolysis Over -MnO2 Catalyst: Preparation, Characterizations and Influencing Factors

MnO2 was screened from various metal oxides and different crystal structures of MnO2 were prepared, which were used to hydrolyze urea process wastewater for energy conservation and environmental protection. The characterizations of XRD, SEM, Raman, FT-IR, XPS and H-2-TPR were employed and the hydrolysis experiments were carried out, demonstrating that oxygen vacancy on the surface of MnO2 might be the catalytic activity source on urea hydrolysis. By optimizing reaction influencing factors, the residual urea concentration reduced to 1.61mg/L over -MnO2, far below the effluent standard. Meanwhile, the temperature of heterogeneous hydrolysis over -MnO2 dropped drastically compared with that of thermal hydrolysis. Further, the kinetic parameters of hydrolysis were obtained over -MnO2. And -MnO2 also showed excellent recycling ability on the reused test. [GRAPHICS] .