木焦油基活性碳的制备及其对亚甲基蓝的吸附性能研究

Preparation of activated carbon derived from wood tar and its adsorption property for methylene blue

摘要:

木焦油是木质生物质材料的高温裂解产物。以木焦油为碳源,以甲醛化处理后的木焦油为前体,通过碳化-活化制备木焦油基活性碳材料。并以制备的木焦油基活性碳为吸附剂,研究了其对模拟水体中亚甲基蓝的吸附性能。结果表明,以木焦油为前驱体经高温碳化活化制备的多孔活性碳,比表面积可达1373Sm_²?g_^-1,表面含有丰富的含氧官能团。木焦油基活性碳对亚甲基蓝具有良好的吸附性能,准二级动力学模型能更准确的描述木焦油基活性碳吸附亚甲基蓝的动力学过程。吸附等温线更符合Langmuir等温吸附模型,木焦油基活性碳对亚甲基蓝的最大吸附容量可达559 mg?g_^-1。热力学分析表明亚甲基蓝在木焦油基活性碳上的吸附是放热和自发的。利用木焦油制备的活性碳材料对亚甲基蓝具有较高的吸附容量,是一种具有潜在应用前景的吸附材料。

Abstract:

Wood tar is the pyrolysis product of woody biomass materials. In this study, wood tar was used as carbon source and wood tar treated by formaldehyde was used as precursor to prepare activated carbon by carbonization and activation. The adsorption of methylene blue in the simulated water was investigated by using wood tar based activated carbon as adsorbent. The results show that the porous activated carbon prepared by carbonization and activation at high temperature with wood tar as precursor has a specific surface area of 1373 m2?g-1 and rich oxygen-containing functional groups on the surface ,the quasi-second-order kinetic model more accurately described the adsorption kinetics of methylene blue on activated carbon derived from wood tar, and the adsorption isotherms of methylene blue on activated carbon derived from wood tar are more consistent with Langmuir adsorption isotherm model. The maximum adsorption capacity of methylene blue on activated carbon derived from wood tar was 559 mg?g-1. Thermodynamic analysis shows that the adsorption of methylene blue on activated carbon is exothermic and spontaneous. The activated carbon prepared from wood tar has potential application prospect with the excellent adsorption capacity for methylene blue.