CaO耦合掺氮生物质炭对NO吸附的机理研究

Study on the mechanism of NO adsorption by CaO coupled nitrogen-doped biochar

本研究采用密度泛函理论,探究了不同含氮生物质炭以及CaO耦合掺氮生物质炭对NO吸附性能的影响。理论计算结果表明,掺氮生物质炭在N-down吸附方式下对NO吸附效果更好,且掺杂N-5生物质炭(CN-5)较其含氮基团生物质炭对NO的吸附能更高,其吸附能为-41.22 kJ/mol。CaO显著提升了生物炭对NO的吸附能力,且CaO耦合含N-5生物质炭(CaO/CN-5)的基底作为电子供体为NO提供更多电荷,其吸附能比CN-5高出216.862 kJ/mol,CaO和N-5基团耦合作用下显著提高生物炭的吸附性能。生物炭表面NO的吸附量会随着温度的升高而减少,增加含N-5生物质炭的数量对NO的吸附更有利,而CaO的耦合进一步提高了CN-5表面NO的吸附量,在273 K时,CaO/CN-5体系的吸附量可以达2.846 mmol/g。

In this study,density functional theory was used to explore the effects of different nitrogenous biochars and CaO-coupled nitrogen-doped biochar on the adsorption performance of NO.The theoretical calculation results showed that nitrogen-doped biomass char had a better adsorption effect on NO under N-down adsorption mode,and the adsorption energy of N-5 biomass char(CN-5)was higher than that of nitrogen-containing biochar,and its adsorption energy was−41.22 kJ/mol.CaO significantly improved the adsorption capacity of biochar to NO,and CaO coupled with the substrate containing N-5 biochar(CaO/CN-5)as an electron donor provides more charge for NO,and its adsorption energy was 216.862 kJ/mol higher than that of CN-5,and the adsorption performance of biochar was significantly improved under the coupling of CaO and N-5 groups.The adsorption capacity of NO on the surface of biochar decreased with the increase of temperature,and increasing the amount of biochar containing N-5 was more conducive to the adsorption of NO,while the coupling of CaO further increased the adsorption capacity of NO-5 surface NO,and the adsorption capacity of CaO/CN-5 system reached 2.846 mmol/g at 273 K.