Supported MnFeOx catalysts have been prepared using Al2O3 as the substrate and were investigated for NH3-SCR. The 20% MnFe/Al2O3 catalyst removed over 80% of NOx with an N2 selectivity exceeding 90% at temperatures between 80 and 340 °C. The results from the various characterization studies indicated that the increased activity of MnFe/Al2O3 catalysts can be primarily linked to the increased chemisorbed oxygen species and Fe3+ concentrations, greater reducibility, and higher adsorption capacity for NH3. These characteristics are the outcome of the strong interaction, larger specific surface, and abundant acidic sites. Additionally, in situ DRIFTS analysis of the reaction mechanism revealed that the E–R and L–H mechanisms were responsible for the NH3-SCR reaction over the 20% MnFe/Al2O3 catalyst.
Ting He,Jie Sun,Liangwei Deng,Jialin Ming,Changwei Hu
Due to its high efficiency, Fe(II)-based catalytic oxidation has been one of the most popular types of technology for treating growing organic pollutants. A lot of chemical Fe sludge along with various refractory pollutants was concomitantly produced, which may cause secondary environmental problems without proper disposal. We here innovatively proposed an effective method of achieving zero Fe sludge, reusing Fe resources (Fe recovery = 100%) and advancing organics removal (final TOC removal > 70%) simultaneously, based on the in situ formation of magnetic Ca-Fe layered double hydroxide (Fe 3 O 4 @CaFe-LDH) nano-material. Cations (Ca 2+ and Fe 3+ ) concentration (≥ 30 mmol/L) and their molar ratio (Ca:Fe ≥ 1.75) were crucial to the success of the method. Extrinsic nano Fe 3 O 4 was designed to be involved in the Fe(II)-catalytic wastewater treatment process, and was modified by oxidation intermediates/products (especially those with COO − structure), which promoted the co-precipitation of Ca 2+ (originated from Ca(OH) 2 added after oxidation process) and by-produced Fe 3+ cations on its surface to in situ generate core-shell Fe 3 O 4 @CaFe-LDH. The oxidation products were further removed during Fe 3 O 4 @CaFe-LDH material formation via intercalation and adsorption. This method was applicable to many kinds of organic wastewater, such as bisphenol A, methyl orange, humics, and biogas slurry. The prepared magnetic and hierarchical CaFe-LDH nanocomposite material showed comparable application performance to the recently reported CaFe-LDHs. This work provides a new strategy for efficiently enhancing the efficiency and economy of Fe(II)-catalyzed oxidative wastewater treatment by producing high value-added LDHs materials.
危险品化学品经营许可证（带存储）