Chemical Engineering Journal | 2019
Enhanced 2, 4-dichlorophenol degradation at pH 3–11 by peroxymonosulfate via controlling the reactive oxygen species over Ce substituted 3D Mn2O3
Abstract
Abstract Peroxymonosulfate (PMS) activation has drawn increasing attention in eliminating the recalcitrant organic pollutants in water. Manipulation of generated reactive oxygen species (ROS) over Ce doped Mn2O3 during the PMS activation was firstly reported for the complete degradation of 2,4-dichlorophenol (2,4-DCP) in this study. Ce in-situ introduction can greatly enhance the PMS activation performance of Mn2O3. For example, 100% of 2,4-DCP degradation can be obtained at 90\u202fmin over 4\u202fwt% Ce doped Mn2O3 at pH 7 (82.1% for Mn2O3 at 90\u202fmin). The reaction rate constant (k) was also about 3.6 times higher than that of Mn2O3 (0.0668\u202fmin−1 for Ce doped Mn2O3 vs. 0.0186\u202fmin−1 for Mn2O3). Besides 1O2, OH and SO4 − were identified and involved in 2,4-DCP degradation process over Ce doped Mn2O3, while only 1O2 was detected over 3D Mn2O3. Moreover, the contribution of OH and SO4 − to 2,4-DCP degradation can be regulated by adjusting the Ce doping amount. The key role of Ce substitution in the regulation of reactive oxygen species was further investigated by XPS and electrochemical experiments. The Ce dopant can lead to a higher current density and greater reductive capability due to the improved charge transfer capability, which is important to the generation of more aggressive OH and SO4 − and complete 2,4-DCP degradation.