化学活化法制备酚醛基活性炭纤维及其吸附性能

Preparation of Phenolic Activated Carbon Fiber by Chemical Activation Method and Its Adsorption Properties

以酚醛纤维为原料、KOH为活化剂,采用化学活化法制备酚醛基活性炭纤维(PACF),并以亚甲基蓝(MB)染料溶液作为吸附对象,对其吸附性能和吸附机理进行研究,同时采用扫描电子显微镜和比表面积及孔隙度分析仪对其微观形貌和比表面积及孔结构进行分析。结果表明:所制备的PACF得率高达47.01%,比表面积为1378.48 m2/g,总孔容为0.60 cm^3/g,平均孔径为1.52 nm,微孔率为90.62%,是一种以微孔为主的多孔性高吸附材料;当MB染料溶液的初始质量浓度为300 mg/L、pH为5时,最有利于PACF对其吸附,此时吸附量高达468.52 mg/g。吸附平衡和吸附动力学研究表明:PACF对MB染料溶液的吸附过程更符合Langmuir等温线模型和准二级动力学模型。此外,颗粒内扩散模型分析表明:外扩散和粒子内扩散都是PACF对MB染料分子吸附过程速率的控制步骤。

Phenolic-based activated carbon fiber(PACF)is prepared by using phenolic fibers as raw materials a nd KOH as an activator via chemical activation method.The adsorption properties and adsorption mechanism of PACF are studied by using methylene blue(MB)dye solution as adsorbate and their morphology,specific surface area and pore structure are also analyzed by using scanning electron microscope and specific surface area and porosity analyzer.The results show that the yield of as-prepared PACF is up to 47.01%,the specific surface area is 1378.48 m2/g,the total pore volume is 0.52 cm^3/g,the average pore diameter is 1.52 nm,and the microporosity ratio is 90.62%,indicating that PACF is a kind of highly microporous adsorption materials.When the initial concentration of MB dye solution is 300 mg/L and the pH value is 5,it is most beneficial for the adsorption of MB onto PACF,and the corresponding adsorption capacity is as high as 468.52 mg/g.Adsorption equilibrium and adsorption kinetics studies shows that the adsorption process of MB onto PACF fits better with Langmuir isotherm model and quasi-secondary kinetic model.Besides,the intraparticle diffusion model analysis shows that the internal diffusion during adsorption is the primary rate control step,but not the only rate control step.