Bamboo/ lignite-based activated carbons produced by steam activation with and without ammonia for SO 2 adsorption
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摘要:
以竹炭与褐煤混合料压块制备出柱状母料,500 °C炭化 30 min 后,经 0 ~21. 91% 氨水气化,850 °C活化 2 h,获得胺化竹木/ 褐煤活性炭。 采用 BET 和 XPS 研究竹木/ 褐煤活性炭的孔结构和表面化学,在 100°C 下考察活性炭对模拟烟气 (0. 1439% SO 2 、8. 02% O 2 和 10. 11%水蒸气)中 SO 2 的脱除性能。 结果表明,氨水活化与水蒸气活化形成的竹木/ 褐煤活性炭孔径分布类似,主要分布于 1 ~2. 5 nm, 2. 42%氨水活化制备的活性炭硫容是水蒸气活化的 1. 52 倍;两种活性炭表面有相同种类的含碳基团,氨水活化后活性炭表面出现了类吡啶或类腈基团和胺、酰胺、酰亚胺及类吡咯基团;竹木/ 褐煤活性炭的脱硫性能主要与类吡啶基团有关。
Abstract:A columnarbamboo/ lignite material was prepared by briquetting a mixture of bamboo carbon and lignite. Activated carbons were obtained by carbonizing the material at 500 °C for 30 min, followed by activation at 850 °C for 2 h using either steam or a gaseous mixture of ammonia in water with an ammonia concentration of 2. 42 mass%. The ammonia-activated carbon was soaked in 21. 91% ammonia water for 5 h and dried at 200 °C to modify its surface chemical properties. The pore structure and surface chemical states of the activated carbons were investigated by physical adsorption and XPS. Their desulfurization performance was evaluated in a simulated flue gas (SO 2 0. 1439%, O 2 8. 02% and water vapor 10. 11%) at 100°C. Results show that the activated carbons produced with and without ammonia have similar pore size distributions in the range 1-2. 5 nm. Sulfur adsorption capacity of the ammonia-activated one (106. 1 mg/ g) is significantly higher than those of the steam-activated one (69. 8 mg/ g). Surface modification of the ammonia-activated carbon further improves its sulfur adsorption capacity to 155. 9 mg/ g. The surfaces of the two kinds of activated carbons contain the same type of carbon groups. The ammonia-activated carbon and its surface modified derivative have similar nitrogen contents with a similar proportion of pyridine or nitrile groups (398. 3-398. 9 eV), amine, amide, imide and pyrrole class groups (400. 2-400. 8 eV).
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Key words:
- Bamboo /
- Lignite /
- Activated carbon /
- Amination /
- Desulphurization performanc
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