污泥活性炭的结构特征及表面分形分析

以城市污水厂污泥为主要原料添加适量添加剂, 采用ZnCl₂化学活化法制备的污泥活性炭, 借助XRD, BET法, FT-IR, SEM等现代分析测试方法结合液相吸附法, 表征结构特征和分析表面分形维数. 结果表明: 在适宜的活化温度、活化时间、ZnCl₂浓度、原料粒度等工艺条件下, 加入少量添加剂制备的污泥活性炭, 最可几孔径分布在4.16 nm左右,平均孔容0.4484～0.5122 mL?g^－1, 比表面积为634.8～748 m²?g^－1, IR峰中出现C—OH, C—H, N＝O, C＝C功能组, 孔结构是具有平行壁的狭缝状介孔结构. 由液相吸附法得到的污泥活性炭分维近似为2, 属于低分维二维表面.

Structure Characterization and Surface Fractal Analysis of Sludge Activated Carbon

Using municipal wastewater sludge as raw material, sludge activated carbon was prepared by ZnCl₂ activation agent and addition of adequate additive. Its structure and absorption were characterized by means of adsorption isotherms, XRD, BET, FT-IR, SEM, etc., and its fractal dimension D value was determined by the method of adsorption from solution. The results show that the activated carbon produced under the condition of favourable pyrolyzation temperature, solution concentration of ZnCl₂-immersed sludge, particle diameter of the raw material and adequate additive, exhibited BET surface area of 634.8～748 m²?g^－1 and the most probable pore size of ca. 4.16 nm. Its IR peaks of C—OH, C—H, N＝O and C＝C confirmed existence of corresponding function groups. It has narrow mesoporous structure with parallel wall. The obtained fractal dimension D value of the sludge activated carbon derived by the method of adsorption from solution is close to 2. The sludge activated carbon can be characterized by low fractal dimension.