以城市污水厂剩余污泥为原料,用氯化锌活化法研究一种柱状污泥基活性炭(CSAC)的制备方法及其工艺条件优化,并选择粉末污泥基活性炭(PSAC)和一种商品煤质碳(MAC)作为对照,考察了CSAC对重金属离子Cu(Ⅱ)和Ph(Ⅱ)及有机污染物硝基苯的吸附去除效能.结果表明,CSAC的比表面积及微孔容积分别是306.9m2·g^-1和0.109cm3·g^-1,仅为MAC的36.7%和23.6%,但其对Cu(Ⅱ)和Ph(Ⅱ)的平衡吸附量却远远高于MAC,说明CSAC表面存在的高含量酸性官能团在吸附去除重金属过程中起到了重要的作用.由于制备原料相同及制备工艺相似,CSAC与PSAC的理化性质基本相同,两种炭的表面酸性官能团含量较高,对Cu(Ⅱ)和Pb(Ⅱ)均具有较好的吸附去除效果,优于MAC.只是CSAC的比表面积和微孔容积略低于PSAC;在对硝基苯的吸附实验中,CSAC及PSAC的吸附效率均远远低于MAC.说明在对有机物硝基苯的吸附中,活性炭的比表面积等物理性质起到了较大的作用.同时,所制备的CSAC的稳定度大于95%,易于分离回收,不会造成二次污染.适合废水中重金属离子的吸附去除.
This study investigated and optimized a preparation method of columnar sludge-based activated carbon (CSAC) using municipal excess sludge as a raw material and ZnC12 as an activation agent. The adsorption capacities of CSAC for Cu(Ⅱ), Pb( Ⅱ ) and nitrobenzene were also investigated and compared with those of two other types of activated carbon : commercial coal-based activated carbon (MAC) and powder sludge-based activated carbon (PSAC). The results show that the specific surface area (BET) and micro-pore volume of CSAC were 306.9 m2.g-1 and 0. 109 cm3.g-1 , respectively, accounting for only 36.7% and 23.6% of those of MAC. However, the adsorption capacities of CSAC for Cu( Ⅱ) and Pb( Ⅱ ) were much higher than those of MAC, which indicated that the surface of CSAC with rich acidic functional groups would be beneficial to the adsorption of heavy metals. With a same raw material and a similar preparation method, physiochemical properties of CSAC and PSAC were basically the same. Both materials had rich acidic functional groups and high adsorption efficiencies of Cu(Ⅱ ) and Pb(Ⅱ ). In terms of nitrobenzene, the adsorption capacities of CSAC and PSAC were far below that of MAC, indicating that the adsorption of nitrobenzene was highly associated with physical properties of adsorbents, e.g. , specific surface area. CSAC can be easily separated and recycled for its high stability (95%). Therefore, CSAC was a suitable material for adsorptive removal of heavy metal ions from wastewaters.