吴铎教授与吴张雄教授合作在Journal of Colloid and Interface Science上发表研究论文

Facile synthesis of alkaline-earth metal manganites for the efficient degradation of phenolic compounds via catalytic ozonation and evaluation of the reaction mechanism

Cunxia Fang, Xingmin Gao, Xiangcheng Zhang, Jiahui Zhu, Sheng-Peng Sun, Xiaoning Wang, Winston Duo Wu *(吴铎) , Zhangxiong Wu *(吴张雄)

 

Suzhou Key Laboratory of Green Chemical Engineering, School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Jiangsu, PR China

 

Journal of Colloid and Interface Science 551 (2019) 164--176

 

In this paper, we demonstrate the facile and general synthesis of alkaline-earth metal manganites, denoted as A(Mg, Ca, Ba)MnxOy, for efficient degradation of high-concentration phenolic compounds via catalytic ozonation. The representative CaMnxOy oxides show a hierarchical spherical structure constructed by crystalline nanorods and numerous macropores. They possess mixed Mn4+/Mn3+ chemical valences and abundant surface hydroxyl (OH) groups. The ozone (O3) decomposition rate on the CaMnxOy catalysts is greatly accelerated and follows the first-order law. These catalysts are promising for the degradation of phenolic compounds via catalytic ozonation, exhibiting rapid pseudofirst-order degradation kinetics, a high total organic carbon (TOC) removal efficiency and an excellent stability. Under optimized conditions (a low O3 dosage of 1.5 mg/min and a catalyst dosage of 7.5 g/L), for the treatment of concentrated phenol (50–240 mg/L), the CaMnxOy catalysts show 100% degradation and 50–70% mineralization within 1.0 h. The Ca2+ ions are essential to create redox Mn4+/Mn3+ couples and to significantly reduce manganese leaching. High surface ratios of Mn4+/Mn3+ and OH/lattice oxygen (Olat) are beneficial for enhancing the catalytic performance. Superoxide anion free radicals (O2) and singlet oxygen (1O2) are the predominant reactive species for the oxidation degradation. The O2 reaction pathway is proposed. Specifically, the surface OH sites activate O3, displaying highly enhanced decomposition rates. The generated O2 and 1O2 play a role in oxidation. The redox Mn4+/Mn3+ and the Olat/oxygen vacancy (Olat/Ovac) couples play important roles in electron transfer. The proposed mechanism is supported by active site probing, radical scavenging, spectroscopic studies, and the results in the degradation of substituted phenols.

 

  

链接:https://www.sciencedirect.com/science/article/pii/S002197971930548X?via%3Dihub