Enhancement of the denitrification efficiency over low-rank activated coke by doping with transition metal oxides
Enhancement of the denitrification efficiency over low-rank activated coke by doping with transition metal oxides
复制标题
通过掺杂过渡金属氧化物提高低阶活性焦的脱硝效率
DOI：
10.1002/cjce.23698
复制
发表时间：
2020-01-21
影响因子：
2.1
通讯作者：
Chen, Guanyi
中科院分区：
文献类型：
--
作者：
Ye, Meng;Cheng, Chungui;Chen, Guanyi
低煤阶活性焦（AC）因其多污染物协同脱除能力而被广泛应用于工业烟气净化。为提高活性炭（AC）对NH3选择性催化还原（SCR）NO的脱硝能力，采用溶剂浸渍法将几种过渡金属（Fe、Mn、Ce、V）氧化物均匀负载到AC中。与未改性活性炭相比，改性活性炭的脱氮效率达到90%以上。采用N2吸附-脱附和拉曼光谱技术对活性炭样品的孔径分布和晶体结构进行了表征。过渡金属氧化物的引入对活性炭的孔结构影响不大，但增加了含氮官能团，有利于NO的去除。利用X射线光电子能谱（XPS）分析了脱氮前后金属元素的价态变化。反应结束后，低价金属氧化物的含量增加，表明过渡金属氧化物参与了NO与NH3的反应。高价金属氧化物将NO氧化为NO2，NO2更容易与NH3反应，从而提高脱氮效率。重要的是，在SO2存在下，改性活性炭仍然表现出较高的脱氮性能。这种过渡金属氧化物掺杂方法可以有效提高低阶AC对多污染物烟气中NO的脱除能力。
Low-rank activated coke (AC) is widely used for industrial flue gas purification due to its multipollutant cooperative removal capability. To enhance the denitrification capacity of AC for the selective catalytic reduction (SCR) of NO with NH3, several transition metal (Fe, Mn, Ce, V) oxides were uniformly loaded into AC by solvent impregnation. Compared to untreated AC, modified AC showed excellent denitrification efficiency above 90%. N-2 adsorption-desorption and Raman spectroscopy techniques were used to characterize the pore size distribution and crystal structure of AC samples. The introduction of transition metal oxides had little effect on the pore structure of AC but increased the nitrogen-containing functional groups, which facilitated NO removal. Moreover, x-ray photoelectron spectroscopy (XPS) was used to analyze the valence changes of metal elements before and after denitrification. After the reaction, the content increase of the low-valence metal oxides indicated that the transition metal oxides were involved in the reaction of NO with NH3. High-valence metal oxides oxidized NO to NO2, which reacts more easily with NH3, thereby increasing the denitrification efficiency. Importantly, in the presence of SO2, modified AC still presented high denitrification performance. This transition metal oxides doping method can effectively improve the ability of low-rank AC to remove NO in multi-contaminant flue gas.