Tianjin Key Lab of Biomass/Wastes Utilization, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, P.R. China.
Beijing Key Lab of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124, P. R. China.
Environ Sci Technol. 2022 Sep 20;56(18):13379-13390. doi: 10.1021/acs.est.2c03811. Epub 2022 Sep 8.
The evaluation of the poisoning effect of complex components in practical gas on DCM (dichloromethane) catalytic ozonation is of great significance for enhancing the technique's environmental flexibility. Herein, Ca, Pb, As, and NO/SO were selected as a typical alkaline-earth metal, heavy metal, metalloid, and acid gas, respectively, to evaluate their interferences on catalytic behaviors and surface properties of an optimized urchin-like CuMn catalyst. Ca/Pb loading weakens the formation of oxygen vacancies, oxygen mobility, and acidity due to the fusion of Mn-Ca/Pb-O, leading to their inferior catalytic performance with poor CO selectivity and mineralization rate. Noticeably, the presence of As induces excessively strong acidity, facilitating the inevitable formation of byproducts. Catalytic co-ozonation of NO/DCM is achieved with stoichiometric ozone addition. Unfortunately, SO introduction brings irreversible deactivation due to strong competition adsorption and the loss of active sites. Unexpectedly, Ca loading protects active sites from an attack by SO. The formation of unstable sulfites and the released Mn-O structure offset the negative effect from SO. Overall, the catalytic ozonation of DCM exhibits a distinctive priority in the antipoisoning of metals with the maintenance of DCM conversion. The construction of more stable acid sites should be the future direction of catalyst design; otherwise, catalytic ozonation should be arranged together with post heavy metal capture and a deacidification system.
评价实际气体中复杂成分对 DCM（二氯甲烷）催化臭氧化的中毒效应，对于提高该技术的环境灵活性具有重要意义。在此，选择 Ca、Pb、As 和 NO/SO 分别作为典型的碱土金属、重金属、类金属和酸性气体，来评估它们对优化后的海胆状 CuMn 催化剂的催化行为和表面性质的干扰。Ca/Pb 负载由于 Mn-Ca/Pb-O 的融合，削弱了氧空位的形成、氧迁移性和酸性，导致其催化性能较差，CO 选择性和矿化率较差。值得注意的是，As 的存在会诱导出极强的酸度，促进副产物的必然形成。NO/DCM 的催化共臭氧化通过计量臭氧添加来实现。然而，SO 的引入会由于强烈的竞争吸附和活性位的损失而导致不可逆失活。出人意料的是，Ca 负载保护活性位免受 SO 的攻击。不稳定的亚硫酸盐的形成和释放的 Mn-O 结构抵消了 SO 的负面影响。总的来说，DCM 的催化臭氧化在抗金属中毒方面表现出明显的优先性，同时保持了 DCM 的转化率。构建更稳定的酸位应该是催化剂设计的未来方向；否则，应将催化臭氧化与重金属捕获和脱酸系统一起安排。
