核壳结构污泥基陶粒对抗生素的吸附机理研究

Adsorption Mechanism of Antibiotic by Sludge Based Ceramsite with Core-Shell Structure

随着城镇化的不断发展,污水处理厂剩余污泥的处置形势严峻。污泥具有结构疏松,孔隙率大,比表面积大等特性,将其作为主要基体,蒙脱石为黏结剂,辅以粉煤灰为助剂,制备一种核壳结构的污泥基陶粒,并以盐酸四环素作为处理对象检验其吸附性能。结果表明,当蒙脱石的掺量为20%时,污泥陶粒的内核具有疏松的大孔结构,外壳具有致密的微孔结构,SBET为49160 cm^(2)/g。污泥陶粒对盐酸四环素的最大吸附量为7.95 mg/g,其吸附过程遵循准二级动力学模型和Freundlich等温吸附模型。扫描电镜(SEM)和能谱分析(EDS)显示,核壳结构的污泥陶粒主要是靠内核的大孔结构发挥吸附作用,大孔结构提供充足的吸附空间;外壳的微孔结构发挥扩散作用,微孔结构为盐酸四环素扩散提供孔隙通道。

With the continuous development of urbanization,the disposal of residual sludge in sewage treatment plants has become serious,which has the characteristics of loose structure,large porosity,large specific surface area.A core-shell structure sludge based ceramsite particle was prepared by using the sludge as the main matrix,montmorillonite as the binder and fly ash as the auxiliary agent.The adsorption performance of sludge ceramsite was tested by tetracycline hydrochloride solution.The results showed that when the content of montmorillonite was 20%,the core of sludge ceramsite had loose macroporous structure,and the shell had dense microporous structure.It had rich pore structures with a specific surface area of 49160 cm^(2)/g.The maximum adsorption capacity of sludge ceramsite to tetracycline hydrochloride was 7.95 mg/g.The adsorption process followed the pseudo-second-order kinetic model and Freundlich isothermal adsorption model.SEM and EDS showed that the core-shell structure of sludge ceramsites mainly depended on the large pore structure of the core,which provided sufficient adsorption space.The microporous structure of the shell played a role in diffusion,and the microporous structure provided pore channels for tetracycline hydrochloride diffusion.