萝藦绒活性炭纤维制备及对亚甲基蓝的吸附性能

Preparation of Activated Carbon fiber Based on Metaplexis japonica Seed Hair Fiber and Its Adsorption Property for Methylene Blue

摘要:

摘要：天然中空萝藦绒(Mj-fiber)经除蜡、磷酸活化和高温炭化工艺后，制备出活性炭纤维(ACF)，采用SEM、XRD、Roman 和BET等方法对活性炭纤维微观形貌及聚集态结构进行了表征。结果表明，活性炭纤维系石墨微晶化无序结构，具有高中空特性和多级微孔表面形貌，总孔容达1.357 cm3/g，比表面积达1882.003 m2/g。制备的活性炭纤维可快速吸附溶液中的亚甲基蓝染料分子，吸附过程符合准二级动力学方程，吸附等温线符合Langmuir模型，并以物理吸附为主，理论最大吸附量达947.372 mg/g；热力学分析结果表明：吸附吉布斯自由能△G0<0，吸附焓变△H0>0，表明吸附系自发过程，并与温度呈正相关；此外还分析了溶液pH、电解质浓度对活性炭纤维吸附性能的影响规律。

Abstract:

Abstract: The activated carbon fiber (ACF) was fabricated of natural hollow metaplexis japonica seed hair fiber(Mj-fiber) successfully through dewaxing, activation by phosphoric acid and carbonization process at high temperature. The micromorphology and aggregate structure of the ACF were characterized by SEM、XRD、Roman and BET. The results demonstrate that our as-prepared ACF, with graphite-like microcrystalline and disorder structure, possesses high hollow characteristic and surface morphology of multi-stage pores distribution. The total pore volume and specific surface area of our ACF is 1.357 cm3/g and 1882.003 m2/g, respectively. More importantly, the ACF displays excellent absorbility of methylene blue dye molecules in solution. The sorption processes of our ACF follow the pseudo-second-order kinetic equation and the adsorption isotherm conforms to the Langmuir model. The physical absorption dominates, and the theoretical maximum adsorption capacity can reach up to 947.372 mg/g. Furthermore, the adsorption Gibbs free energy △G0<0 and the adsorption enthalpy change △H0>0, obtained from the results of thermodynamic analysis, indicating the absorption behavior is a spontaneous process and positively correlated with temperature. In addition, the effects of pH and electrolyte concentration on the adsorption properties of ACF were analyzed systematically.