KOH活化对焦炭孔隙结构以及导电特性影响

Characteristics of Pore Structure and Electrical Conductivity of Charcoal Prepared by KOH Activation

以木质素为原料,采用化学活化法(KOH活化剂)进行活化处理,分别探讨了不同活化温度、活化时间、KOH/木质素质量比R值对焦炭孔隙结构以及导电特性的影响规律。通过氮吸附(BET)、扫描电镜(SEM)和电阻率测定仪对焦炭性能进行表征。结果表明,KOH活化有效改善了焦炭的孔隙结构,通过增加焦炭微孔量提高了焦炭比表面积。实验得出的最优活化工况为:活化温度800℃,活化时间1 h,质量比R=3,此时焦炭达到最大比表面积。KOH活化后,焦炭电阻率最低可降至0.226Ω·cm。

The charcoal was prepared from lignin by chemical activation with KOH under different conditions.The influences of parameters such as activation temperature,time and mass ratio of KOH to lignin(R) were discussed.Both nitrogen adsorption isotherm as Brunauer-Emmett-Teller(BET)and scanning electron microscopy(SEM) were used to identify the structure characteristics,while the electrical resistivity of charcoal was determined by a GM- II analyzer.The results showed that the obtained charcoal possessed a maximum specific surface area at 800° C for 1 h with R = 3.After activation,the lowest electrical resistivity of charcoal could reach at 0.226 fi-cm.