活化温度对聚丙烯腈基活性中空炭纤维结构和吸附性能的影响

Effect of activation temperature on structure and adsorptivity of polyacrylonitrile-based activated carbon hollow fiber

用质量分数为4%的磷酸氢氨溶液预处理聚丙烯腈(PAN)中空纤维,经预氧化及炭化后,用二氧化碳气体在不同温度下活化40 min,得到PAN基活性中空炭纤维(PAN-ACHF).考察了活化温度对PAN-ACHF的比表面积、孔径分布、形态和吸附性能的影响.结果表明,随着活化温度的升高,PAN-ACHF表面的孔逐渐加深,且数目逐渐增多,比表面积逐渐增大;当活化温度为900℃时,BET比表面积最大为1422 m2/g,中孔的比表面积也达到最大,为1234 m2/g,且孔径主要集中在2～5 nm;PAN-ACHF对肌酐和VB12的吸附率都随着活化温度的升高而增大,当活化温度为900℃时,PAN-ACHF对肌酐和VB12的吸附率都达到最大值,分别为99%和84%.

Polyacrylonitrile hollow fiber was pretreated with 4% ammonium hydrogen phosphate solution by weight and successively activated with carbon dioxide at different temperature for 40 min after preoxidization and carbonization, thus the polyacrylo-nitrile-based activated carbon hollow fiber (PAN-ACHF) was produced. The effect of activation temperature on specific surface area, pore size distribution, morphology and adsorptivity of PAN-ACHF was studied. The results showed that the pores on the surface of PAN-ACHF were increased in depth and number and the specific surface area of the pores was increased gradually while raising the activation temperature. The specific surface area of BET and mesopores reached the maximum of 1 422 m2/g and 1 234 m2/g, respectively, at activation temperature of 900℃ and the pore size was mostly distributed in the range of 2 -5 nm. The adsorptivity of PAN-ACHF to creatinine and VB12was increased with the activation temperature until reaching its maxi-mium of 99% and 84% , respectively, at activation temperature of 900℃.