污泥活性炭的制备及对甲苯吸附性能研究

Preparation of Sludge-based Activated Carbon and Adsorptive Properties of Toluene

以城市污水厂脱水污泥为原料,采用ZnCl2化学活化法,通过添加适量锯末(SAC-W)或椰壳(SAC-C)制备出不同污泥活性炭,其比表面积分别为450.3 m2/g和539.4 m2/g,比纯污泥活性炭的比表面积增加了31.63%和57.67%。将污泥活性炭和选用的煤质活性炭(CAC)用于甲苯动态吸附实验,研究不同活性炭的吸附性能。结果表明,在相同的甲苯初始浓度下,平衡吸附量大小顺序为SAC-C>CAC>SAC-W,污泥活性炭表现较好的吸附性能。对污泥活性炭进行理化性能分析,发现中孔和化学吸附作用对吸附量增加有一定贡献。污泥活性炭的吸附平衡与Langmuir方程拟合较好,相关系数R2为0.995。

With dewatered sludge from municipal wastewater plant as raw material, sludge-based activated carbon was prepared by chemical activation of ZnC12 through mixing with appropriately additive wood （SAC-W） or coconut husk （SAC-C） whose BET surface areas were as high as 450.3 m2/g and 539.4 m2/g, increasing by 31.63% and 57.67% respectively comparing with that of pure sludge activated carbon. Using dynamic adsorption experiments, adsorptive properties for toluene was compared with commercial activated carbon （CAC）. Results indicated that the order of adsorption capacities from high to low were as SAC-C, CAC, SAC-W at the same initial concentration of toluene. SAC has strong adsorption for toluene. The physicochemical properties of SACs were analyzed, and it showed that mesoporous structure and surface chemistry of sludge activated carbon play key role on the removal of toluene. Langmuir equilibrium isotherm model fits better adsorption data with coefficient of 0.995.