The oxidative degradation of contaminants is one of the important water and wastewater treatment technologies. MnO2 is a common soil constituent that demonstrates high oxidative reactivity toward a variety of organic contaminants. Previous studies have shown that different crystalline MnO2 could result in different catalytic activity. However, few studies have investigated the effect of phase structure of MnO2 on the oxidative reactivity. Using triclosan (a widely used antibacterial agent) as a probe compound, the goal of this work was to examine how the phase structure of MnO2 affected its degradation kinetics. Five MnO2 with different phase structures, i.e., α-, β-, δ-, λ-, and ?-MnO2, were synthesized, characterized, and tested for triclosan degradation in aqueous solution. Powder X-ray diffraction patterns of the synthesized MnO2 samples confirmed their phase structures. The oxidative reactivity of -MnO2 (k=1.7 h-1) is much higher than that of α-MnO2 (k= 0.1 h-1) at pH 5. The reactivity difference could result from the difference in surface area, Mn(III) content, conductivity, and/or reduction potential. Therefore, further tests will be conducted to examine these properties to explain the observed different reactivity.

Effect of MnO2 phase structure on its oxidation performance in contaminant removal

254th National Meeting (2017)

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