原料复配制备木质素基成型活性炭研究

Preparation of Lignin-derived Formed Activated Carbon by Compounding Raw Materials

以碱木质素和杉木屑为原料,磷酸为活化剂,制备碱木质素基成型活性炭,考察了碱木质素质量分数、浸渍比、活化温度、活化时间等对活性炭性能的影响。研究结果表明:碱木质素复配杉木屑(碱木质素质量分数50%)后,复配料的表面润湿性显著提高,瞬时水接触角由133.2°(碱木质素)降低至86.6°(复配料);热膨胀系数显著降低,膨胀温度区间的热膨胀系数由2365μm/(m·℃)(碱木质素)降低至45μm/(m·℃)(复配料)。在最佳工艺条件即碱木质素质量分数50%、浸渍比1.5∶1(纯磷酸与复配料质量比)、活化温度500℃、活化时间90 min下,制备的成型活性炭得率41.76%,碘吸附值1070 mg/g,亚甲基蓝吸附值255 mg/g,强度90%,比表面积1646 m^(2)/g,总孔容积为0.795 cm^(3)/g,其中孔径小于5 nm的孔容积占总孔容积的97.2%。

Lignin-derived formed activated carbon was prepared from alkali lignin and fir sawdust using phosphoric acid as the activator.The effects of alkali lignin mass fraction,impregnation ratio,activation temperature,and activation time on the properties of activated carbon were investigated.The results showed that the surface wettability of alkali lignin compounded with fir sawdust(alkali lignin mass fraction of 50%)was significantly improved,and the instantaneous water contact angle decreased from 133.2°(alkali lignin)to 86.6°(compound raw materials).The thermal expansion coefficient in the expansion temperature range decreased from 2365μm/(m·℃)(alkali lignin)to 45μm/(m·℃)(compound raw materials).Under optimal technological conditions of alkali lignin mass fraction of 50%,impregnation ratio of 1.5∶1(mass ratio of pure phosphoric acid to compound raw materials),activation temperature at 500℃,and activation time for 90 min,the prepared activated carbon had the iodine adsorption value of 1070 mg/g as well as the methylene blue adsorption value of 255 mg/g.The yield and strength of activated carbon were 41.76%and 90%,respectively.The specific surface area and pore volume were 1646 m^(2)/g and 0.795 cm^(3)/g respectively,where the pore volume with pore diameter less than 5 nm occupied for 97.2%in the total pore volume.