摘要
以烟草杆为原料,以磷酸为活化剂,采用一步炭化法制备了活性炭。采用正交实验研究了磷酸质量分数、浸渍时间、炭化温度及保温时间对活性炭得率和吸附性能的影响,在最佳工艺条件(磷酸质量分数30%,浸渍时间48 h,炭化温度750℃,保温时间20 min)下,所制备的活性炭其碘吸附值为889.36 mg/g,亚甲基蓝吸附值为21.5 mL/(0.1 g),得率为36.90%。同时测定了该活性炭的液氮吸附等温线,并通过BET、H K方程、D A方程和密度函数理论(DFT)表征了活性炭的孔结构。结果表明,该活性炭为中孔型,BET比表面积为892 m2/g,总孔体积为0.467 8 mL/g,微孔占总孔体积的37.06%,中孔占62.85%,大孔占0.07%。最后采用电子探针和透射电镜分析了活性炭的微观结构,其结构与氮吸附测定的结果较为一致。
Activated carbons are prepared with tobacco stems as raw materials and phosphoric acid as activating agent using a one-step carbonization procedure.Effects of impregnating time and mass fraction of phosphoric acid solution,carbonization temperature and heat preservation time on yield and adsorption properties of activated carbon are systematically studied via orthogonal experiments.The optimum conditions are obtained as follows: the mass fraction of phosphoric acid solution is 30%,the impregnating time is 48h,the carbonization temperature is 750℃ and the heat preservation time is 20min.The experimental results show that the yield of the activated carbon is 36.90% when the adsorption value of methylene blue reached 21.5mL/0.1g and the adsorption value of iodine is 889.36mg/g.Furthermore,the activated carbon manufactured under optimum condition is tested by nitrogen adsorption at 77K.The specific surface area of activated carbon is 892m^2/g by BET method.The porous structures of the activated are investigated by Horvath-Kawazoe equations,Dubinin-Astakhov equations and Density Function Theory.It shows that the activated carbon is mecroporous with 0.4678mL/g for total pore volume which contains micropore volume of 37.06%,The mecropore volume of 62.85% and the macropore volume of 0.07%.Scanning electron microscopy(SEM) and transmission electron microscopy(TEM) study also demonstrated the results of the pore structures analysis.
出处
《化学工业与工程技术》
CAS
2006年第2期1-5,共5页
Journal of Chemical Industry & Engineering
基金
国家自然科学基金资助项目(编号:20167001)
高等学校优秀青年教师教学科研奖励计划资助项目
关键词
活性炭
磷酸
孔径分布
吸附等温线
Activated carbon
Phosphoric acid
Pore size distribution
Isotherm
