Abstract To enhance the SO 2 adsorption of biochar, CO 2 activation and impregnation with methyldiethanolamine (MDEA) was simultaneously employed to improve its physicochemical characteristics. Furthermore, the effects of the pore structure and nitrogen functionality on SO 2 adsorption were also explored. The results show that after CO 2 activation, the specific surface area of biochar increased from 56.91 m 2 /g to 755.35 m 2 /g, while this figure dropped to 25.54 m 2 /g or even lower after impregnation with MDEA. Although the pore structure of activated biochar was destroyed, the surface nitrogen content of the nitrogen-enriched biochar (with 10% MDEA impregnation) increased from 1.46% to its highest level (7.20%); moreover, as indicated by Fourier Transform Infrared (FTIR) spectroscopy, the nitrogen functional groups introduced on the surface of the nitrogen-enriched biochar were mainly C-N. After 10% MDEA impregnation, the maximum SO 2 adsorption capacity increased from 57.8 mg/g to 156.2 mg/g. Changes to physical and chemical properties in the nitrogen-enriched biochar indicate that the nitrogen functional groups on the surface are more important than the pore structure for SO 2 adsorption at 393 K, and that the dominant nitrogen species are quaternary nitrogen.

中文翻译：

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增强CO 2 活化和胺浸渍改性生物炭对SO 2 的吸附性能

摘要 为了增强生物炭对SO 2 的吸附，同时采用CO 2 活化和甲基二乙醇胺（MDEA）浸渍来改善其理化特性。此外，还探讨了孔结构和氮官能度对 SO 2 吸附的影响。结果表明，CO 2 活化后，生物炭的比表面积从56.91 m 2 /g增加到755.35 m 2 /g，而浸渍MDEA后，比表面积下降到25.54 m 2 /g甚至更低。虽然活性生物炭的孔隙结构被破坏，但富氮生物炭（含10% MDEA）的表面氮含量从1.46%增加到最高水平（7.20%）；此外，如傅里叶变换红外 (FTIR) 光谱所示，富氮生物炭表面引入的氮官能团主要是CN。10% MDEA浸渍后，最大SO 2 吸附容量从57.8 mg/g增加到156.2 mg/g。富氮生物炭物理和化学性质的变化表明，在 393 K 吸附 SO 2 时，表面的氮官能团比孔结构更重要，并且主要的氮物种是季氮。