In view of the characteristics of high temperature denitrification and low water and sulfur resistance of single manganese-based catalysts, a vanadium–manganese-based ceramic filter (VMA(14)-CCF) was prepared by the impregnation method modified with V. The results showed that the NO conversion of VMA(14)-CCF was more than 80% at 175–400 °C. At 225–300 °C, the conversion of NO can reach 100%. High NO conversion and low pressure drop can be maintained at all face velocities. The resistance of VMA(14)-CCF to water, sulfur and alkali metal poisoning is better than that of a single manganese-based ceramic filter. XRD, SEM, XPS and BET were further used for characterization analysis. The introduction of V protects the MnOx center, promotes the conversion of Mn3+ to Mn4+, and provides abundant surface adsorbed oxygen. The development of VMA(14)-CCF greatly broadens the application range of ceramic filters in denitrification.
Xin Yang,Kaijie Liu,Xinyu Han,Jianheng Xu,Mengyao Bian,Daying Zheng,Haijiao Xie,Yibo Zhang,Xiangguang Yang
It is essential to develop the catalyst for NH 3 -SCR with excellent performance at ultra-low temperature (≤150 °C), and resource recycling is another important part of environmental protection. Based on the principle of environmental friendliness, the LiMn 2 O 4 , one of the waste battery cathode materials, was successfully modified into a novel high-value catalyst for ultra-low temperature NH 3 -SCR through hydrogen ion exchange and two-dimensional vanadic oxide modification. The optimized LiMn 2 O 4 -0.5V-10H catalyst performed the best balance of NO x conversion and N 2 selectivity , with activity reaching 96 % at 150 °C and N 2 selectivity exceeding 70 % at ultra-low temperature. Due to the unique three-dimensional network structural characteristics of LiMn 2 O 4 spinel, hydrogen exchange could exchange Li + from the lattice and increase surface acidity; and a small amount of two-dimensional vanadic oxide loading could appropriately regulate redox ability and increase acidic sites. The in-situ DRIFTS results still showed that the L-H and E-R mechanisms coexisted during the reaction. Moreover, combining first-principles calculations and in-situ DRIFTS, the dual modification of H and V could enhance the adsorption of NH 3 on the surface of LiMn 2 O 4 but weaken the adsorption of NO, and promote the decomposition of nitrites while inhibit the formation of surface nitrate species, which was the core reason for the improvement of N 2 selectivity. The modification mode in this work was simple and inexpensive, which provided a new idea for the high-value utilization of waste batteries and the design of NO x purification catalyst at ultra-low temperature.
危险品化学品经营许可证（带存储）