互花米草厌氧发酵渣活性炭的制备表征及吸附性能研究

利用废弃物互花米草厌氧发酵渣为原料,以H3PO4为活化剂,于N2保护下,在不同的活化温度（400~700℃）和剂料质量比（0.5~3.0）条件下制备活性炭,以低温液氮（N2/77.4 K）吸附测定活性炭的比表面积、孔容及孔径分布,以FTIR、pHPZC测定分析活性炭表面化学性质;以亚甲基蓝为特征污染物,考察所制备的活性炭成品的吸附能力。结果表明,随着剂料质量比的增大,活性炭孔径分布变宽,中孔所占比例增大;在所考察的活化温度范围内,活性炭N2吸附容量大小与BET比表面积呈现相同的趋势。活化温度为500℃、剂料质量比为2.0条件下所制备的活性炭对亚甲基蓝的吸附性能良好,最大吸附容量可达243.90 mg.g-1,符合Langmuir吸附等温模型。亚甲基蓝Langmuir最大吸附容量与活性炭BET比表面积存在一定的线性关系。该活性炭制备方法为互花米草厌氧发酵渣的综合利用找到了新的途径。

Preparation,Characterization and Absorption Capability of Activated Carbon from Anaerobic Digested Residue of S.alterniflora

Activated carbon adsorbents were prepared by phosphoric acid activation of anaerobic digested residue of S.alterniflora in nitrogen atmosphere at various temperatures（400~700 ℃）and at different acid/precursor impregnation ratios（0.5~3.0）.Porous and surface structure were derived from adsorption isotherms（N2 at 77.4 K）.The surface chemistry of the carbons was investigated by infrared spectroscopy and pHPZC.Increasing the impregnation ratio led to a widening of the porous structure with a higher relative contribution of mesoporosity.All the activated carbons prepared within the thermal range invested showed fairly values of adsorption capacity of N2 and its evolution with activa-tion temperature becomes parallel to that of the BET surface area.The potential application of these carbons for the removal of water pollu-tants was investigated by measuring their adsorption capacities for methylene blue as representative of contaminants.The results showed that an impregnation ratio and an activation temperature around 2 g H3PO4.g-1 anaerobic digested residue of S.alterniflora and 500 ℃,respec-tively,were recommended as the best combination of operating conditions to prepare activated carbons for methylene blue adsorption.In addi-tion,the highest adsorption capacity of methylene blue reached 243.90 mg.g-1.It indicated that Langmuir isotherm was more reasonable than Freundlich isotherm for methylene blue adsorption.A reliable correlation between BET surface area and the Langmuir monolayer capacity was obtained.The preparation method of activated carbon provides a new way for the comprehensive utilization of the anaerobic digested residue of S.alterniflora.