磷酸活化制备高吸附性能活性炭的研究

Preparation of High Adsorption Performance Activated Carbon by Phosphoric Acid Activation

以杉木屑为原料,磷酸为活化剂,添加少量浓硫酸作催化剂,经预处理后活化,探讨了不同条件对活性炭性能的影响。结果表明:在浸渍比为2∶1,浓硫酸添加量为1%,预处理温度为240℃,预处理时间为1 h,活化温度为450℃条件下,制得亚甲基蓝吸附值高于338 mg/g,碘吸附值高于1 287 mg/g,得率高于45%的活性炭。研究表明:添加少量浓硫酸溶液作为催化剂,有利于磷酸在木质原料内部的渗透,促进磷酸的活化作用,提高活性炭的吸附性能;预处理时间和温度分别控制在1 h和240℃时能显著提高活性炭吸附能力;浸渍比对活性炭微孔的拓展作用不明显;活化温度对活性炭吸附性能影响较大,450℃为较合适的活化温度。

Activated carbons were prepared using fir sawdust as raw material after pretreatment and the combination of phosphoric acid and sulfuric acid as activator.The methylene blue adsorption value is higher than 338 mg/g,the iodine value is higher than 1 287 mg/g with the yield is higher than 45％.The effect of concentrated sulfuric acid amount,pretreatment time,pretreatment temperature,impregnation ratio and activation temperature on the methylene blue and iodine adsorption properties of the activated carbons were studied.The results showed that adding a small amount of concentrated sulfuric acid solution could promote the penetration of phosphoric acid into lignocellulose,enhance the activation of phosphoric acid,and increase the adsorption capability of activated carbon.The pretreatment time and temperature were controlled for 1 h at 240 ℃.This condition can significantly improve the activated carbon adsorption capacity.The expansion effect of impregnation ratio on the microporous activated carbon was not significant.The activation temperature significantly affects the adsorption capacity of activated carbon,and the activation temperature should be controlled at 450 ℃.