Zhuoyue Liu,Dong Cheng,Haochen Yin,Jianghao Zhao,Jiale Zhang,Rongzhi Chen,Shengjiong Yang,Jing Wei,Gen Wang
Nascent MnO 2 colloids produced during the permanganate oxidation process is highly oxidative and appealing for eliminating emerging organic contaminants (EOCs). However, the nascent MnO 2 colloids usually shows dense bulked structure, which blocks the availability of active sites and further enhancement of the reactivity. Herein, spherical nascent MnO 2 colloids with mesoporous structure were synthesized via redox reactions between colloidal nanospheres of plant polyphenol (e.g., tannic acid) and permanganate. The mesoporous nascent MnO 2 colloids shows highly exposure of active sites with abundant bulk-Mn(III) on the surface (16.2 mol%), and thus exhibits outstanding oxidation performance toward the oxidation of phenolic contaminants. Complete removal of bis-phenol A (BPA, 10 mg/L) was obtained with 1.0 mM of mesoporous nascent MnO 2 colloids in 40 min at neutral pH. Mechanism study reveals that both Mn(III) and Mn(IV) contribute to the oxidation of BPA. The presence of bulk-Mn(III) on the surface greatly promotes the reactivity of the mesoporous nascent MnO 2 colloids, leading to a high kinetic of 0.12 min −1 during the initial 10 min. The nascent mesoporous MnO 2 colloids exhibits high selectivity toward electron rich phenolic contaminants and good performance in complicated water matrix, revealing a promising potential for further application. This work provides a distinct case for engineering novel structured nascent MnO 2 colloids for efficient elimination of EOCs in water.
Jun Wang,Simeng Bi,Li Wei,Yi Shen,Fanpeng Meng,Yang Zhang,Xiaoyao Tan
To probe the underlying mechanisms of carbocatalysis in enhanced permanganate (PM) oxidation and identify the exact roles of nascent MnO 2 , graphene aerogels (GA) were fabricated to activate PM for naproxen (NPX) degradation. All the three GA samples could accelerate NPX oxidation by PM, the rate constants and reaction stoichiometric efficiency (RSE) followed the order of GA900 > GA600 > GA300. Mechanistic studies revealed that Mn(VI), Mn(V) and Mn(III) were not the major reactive species involved in NPX oxidation, but highlighted the essential contribution of electron transfer pathway (ETP) mediated directly by GA and indirectly by nascent MnO 2 . For GA300 with strong electron-donating capability, it mainly served as the electron donor for PM decomposition, and indirectly oxidized NPX via nascent MnO 2 mediated ETP, thereby exhibiting inferior RSE as well as mediocre recycling performance. GA600 and GA900 could serve as the electron shuttle to directly mediate the ETP for NPX degradation, the nascent MnO 2 accumulated on GA framework during the reaction would also mediate the ETP from NPX to PM, thus displaying an obvious accelerating recycling performance. This work provides novel insights into the structure-dominated PM carbocatalysis, which contributes better to development of promising carbocatalysts and utilization of nascent MnO 2 .
危险品化学品经营许可证（带存储）