以烟杆为原料,以水蒸气为活化剂,采用正交实验研究了水蒸气流量、活化时间和活化温度对活性炭得率和吸附性能的影响,最佳工艺条件为活化温度900℃,时间为30分钟,水蒸气流量3.09mL/min,在此条件下制得活性炭产品的碘吸附值为946.52mg/g,亚甲基蓝吸附值为21mL/0,1g,得率为32.64%。同时测定了该活性炭的氮吸附等温线,并通过BET、H-K方程、D-A方程和密度函数理论(DFT)表征了活性炭的孔结构。结果表明:该活性炭为微孔孔型,BET比表面积为1044m^2/g,总孔体积为0.5870mL/g,微孔体积占总孔体积的72.03%,中孔占26.92%。大孔占1.05%。
Activated carbon was prepared by tobacco stems as raw materials and steam as activating agent. The effects of flow rate of steam, activation temperature and hold time on the yield and adsorption properties of activated carbon were systematically studied via orthogonal experiments. Through primary study of the reaction mechanism of activated carbon preparation, the optimum condition has been obtained as follows: flow rate of steam is 3.09 mL/min while activation temperature is 900℃ with hold time is 0.5 hours. Thus the experimental results showed that the yield of the activated carbon was 32.64 % when the methylene blue adsorption reached 21 mL/0.1 g and iodine value was 946.52 mg/g.Furthermore, the activated carbon prepared under optimum conditions was tested by nitrogen adsorption at 77 K. The specific surface area ofactivated carbon is 1044 m^2/g by BET method. The porous structures of the activated carbon were investigated by Horvath-Kawazoe equations, Dubinin-Astakhovequations and Density Function Theory. It was shown that the activated carbon is microporous with 0.5870 mL/g for total pore volume, the total pore volume of 72.03% for micropore volume and 26.92% for mecropore volume and 1.05 % for macropore volume.