淀粉基多孔碳材料的制备及对液体苯的吸附

Preparation and adsorption properties of starch-based porous carbon materials

以玉米淀粉为原料,KOH为活化剂,采用化学活化法制备多孔碳材料吸附危险化学品液体苯。通过热重(TG)分析玉米淀粉在升温过程中的热解行为;采用扫描电镜、X射线衍射仪对多孔碳的微观结构和表面形貌进行表征;利用氮气吸附和脱附等温线计算出BET比表面积、DTF孔径分布及孔容;并从动力学角度研究了多孔碳对苯的吸附行为及吸附性能与孔隙结构的关系。研究表明:在碳化温度为350℃、保温时间30min,活化温度为800℃、保温时间为120min、KOH/C质量比为2∶1条件下,制备的多孔碳以微孔、介孔为主,孔道结构有序,孔隙结构发达,对苯的吸附性能强,吸附量为5 950mg/g;准二级动力学方程比准一级动力学方程及Elovich动力学方程更适合描述淀粉基多孔碳对液体苯的吸附过程。

Porous carbon absorbed benzene was prepared by the the liquid hazardous chemicals chemical activation with corn starch as raw material, KOH as activator. The pyrolysis be havior of corn starch was characterized in the heating process by the TG; the microstructure and surface morphology of the por- ous carbon was analyzed through X-ray Diffraction and Scan E- lectronic Microscope the BET specific surface area, DTF pore size distribution and pore volume were calculated by nitrogen adsorption and desorption isotherms; the kinetic for the adsorp- tion behavior of benzene and the relationship between adsorption properties and pore structure on the porous carbon was studied. The results showed that in the suitable condition of carboniza- tion temperature 350°C, carbonization time 30 rain, activation temperature 800°C, activation time 120 rain, KOH/C 2 ： 1, porous carbons were mainly microporous and mesoporous mate- rials, ordered pore structure, developed pore structure, strong adsorption of benzene and the adsorption capacity was 5 950 mg/g. Pseudo second-order equation is more suitable for descri- bing starch-based porous carbon adsorption process for liquid benzene than pseudo first- order equation and Elovlch equation.