A non-specific surface area dominated catalytic ozonation with CuO modified β-MnO2 in efficient oxalic acid degradation

In this paper, a series of copper oxide supported manganese dioxide (CuXMnT) composites were prepared by the hydrothermal and deposition precipitation methods. The effects of different hydrothermal temperatures (100 degrees C-180 degrees C) and copper doping amounts (1-10 mM) on the structural and physicochemical properties of CuXMnT composites were systematically investigated. The BET, SEM, and XRD characterizations revealed that the CuXMnT composites exhibited a typical rod-like structure. Besides, with the increscent hydrothermal tem-perature, the BET specific surface area decreased and the crystal form of the composites changed from alpha-MnO2 to beta-MnO2. The Cu1Mn180 with low specific surface area (3.277 m(2) g(-1)) exhibited the splendid catalytic ozonation activity and the oxalic acid (OA) removal rate reached 87.5% in O-3/Cu1Mn180 process compared with single ozonation (3.2%). Additionally, it was noteworthy that the excellent catalytic performance of Cu1Mn180 (91.8% of OA removal rate) at pH 3.0 was resulted from the electrostatic adsorption. While, the complexation played a vital role for OA degradation at pH 6.0 and 9.0 with the OA removal efficiencies of 87.5 and 70.3% within 30 min, respectively. Furthermore, Cu1Mn180 could obtain more than 90.9% of OA removal rate during multiple consecutive cycles, representing the satisfactory stability and reusability. Moreover, the multivalent Mn, the structural oxygen species, and Cu species played the key roles for OA degradation in O-3/Cu1Mn180 process at pH 6.0 via the TEM, ESR, XPS and O2-TPD characterizations. Overall, the results presented a promising alternative material for efficient catalytic ozonation application in water.

Automated summary

In this study, CuXMnT composites were prepared by hydrothermal and deposition precipitation methods, and the effects of different hydrothermal temperatures and copper doping amounts on the properties of the composites were investigated. The results showed that Cu1Mn180 exhibited excellent catalytic ozonation activity and stability, making it a promising alternative material for efficient catalytic ozonation application in water.