09-1废水的物理化学处理法-膜.ppt

第四章 废水的物理化学处理法第三节 膜分离技术 1.膜分离技术概述Membranes comparison 从如下几个 方面介绍膜技术 By membrane material and pore size. By driving forces employed and feed flow direction. By mechanisms of separation. By the application in industries. By the geometric configuration. 1.1 Membrane’s pore size Classification of MF, UF, NF and RO are based on the pore size of membrane employed. Separation Spectrum 0.01 NPS Membrane Polymers Cellulose Acetate and Derivatives Polyamides 1.3 Membrane Construction Options 1.4 操作压力 MF, UF, NF and RO all belong to pressure driving membrane. The operation pressure is decided by the resistance of the membrane filtration and as well as the characteristics of the influent water. operation pressure of membrane in order of RONFUFMF. Topical figures is given as follow table . 1.5 By mechanisms of separation The separation mechanism of MF and UF is sieve, just like a strainer（滤网） to separate different material by size. It is belong to physical process. But for NF and RO are more complicated. Beside the sieve mechanism it also involves molecule movement of diffusion and exclusion . It is belong to physical and chemical process. 膜分离的物理化学原理 1.6 By application in industry RO：水的纯化，改善色、味、口感等性质；也用于溶液纯化如乙醇或 乙二醇的提纯 NF：通常用于分离。如用于玉米糖浆的浓缩 UF：广泛用于不同的工业领域。在水处理中，可用于替代凝聚 coagulation, 絮凝flocculation, 沉淀sedimentation, 过滤and media filtration等处理过程. 也是RO和离子交换的理想的预处理步骤。 MF：可用于除去淀粉 starch, 细菌bacteria, 脂肪fat, 霉菌molds, 酵母yeast and 以及乳化油emulsified oils . 1.7 By the geometric configuration（膜组件） 板式Plate and frame membrane 卷式Spiral wound modules 空心纤维膜Hollow fiber membrane 管式Tubular module membrane? 1.8 summary 膜技术广泛应用于物质分离提纯、污水处理和水净化，废气净化。工业应用中的主要难题是膜的价格和堵塞。 膜技术的选择取决于被分离物质及膜的性质。 例如，在水处理中，首先采用MF分离微粒，用UF消毒 ，然后用 NF and RO 除去离子。 Membrane Filtration Process Chen Shuixia/ZSU * 膜分离的概念：利用膜的选择性（孔径大小），以膜的两侧存在的能量差作为推动力，由于溶液中各组分透过膜的迁移率不同而实现分离的一种技术。 膜分离技术主要包括, 反渗透法Reverse Osmosis (RO) 、超过滤法Ultrafiltration (UF) 、微孔过滤Microfiltration (MF) 、 纳滤Nanofiltration