Journal Article

Mn

Liu, Ying, Wang, Weixing, Tang, Mingxing

2024

Overview

In this work, Ce-doped Mn/[gamma]-Al.sub.2O.sub.3 catalysts (Mn (Ce.sub.x)/[gamma]-Al.sub.2O.sub.3) with different Ce/Mn molar ratios were prepared for catalytic ozonation of pollutants in petroleum refinery wastewater (PRW). Results showed that compared to Mn/[gamma]-Al.sub.2O.sub.3 catalyst, the performances of Mn (Ce.sub.x)/[gamma]-Al.sub.2O.sub.3 catalysts were notably improved, especially Mn (Ce.sub.0.20)/[gamma]-Al.sub.2O.sub.3 catalyst demonstrated the highest activity and improved stability for the degradation of PRW (> 97% of chemical oxygen demand (COD) in PRW was removed and the molecules of petroleum-derived pollutants were almost completely degraded in 1.5 h treatment, and the catalyst showed no obvious decrease in activity after 5 cycles). The results of catalyst characterization confirmed that doping Ce changed the growth characteristics of the catalysts, increased the content of active phase [alpha]-MnO.sub.2 in the catalysts and led to the growth of [alpha]-MnO.sub.2 along crystal planes (310) preferentially, prevented catalyst particles from growing, and also enhanced the dispersion of those catalyst particles. Moreover, electron paramagnetic resonance (EPR) experiments revealed that Mn (Ce.sub.0.20)/[gamma]-Al.sub.2O.sub.3 catalyst promoted the production of more hydroxyl radicals (*OH) and superoxide anion (*O.sub.2.sup.-). The influences of catalyst dose, O.sub.3 concentration and pH on the degradation were also investigated. This work provided a theoretical basis and an experimental reference for the preparation of highly active Mn-based catalysts for deep ozonation of PRW by HCOP.

• Publisher: Springer
• Subject: Catalysts / Ozonization / Petroleum refineries / Pollutants / Wastewater