In membrane filtration special attention is paid to an effect which influences productivity and operational costs: membrane fouling. Membrane fouling occurs when a particle deposits on the membrane surface or in the membrane pores, thereby decreasing the performance of the membrane. Membrane fouling can be controlled by targeted surface modifications. This article examines how surface charge analysis contributes to the optimization of membrane performance and how it can best be performed.
Membranes are used for selective separation in a variety of filtration processes. Applications of membrane technologies and different membrane types are manifold: Reverse osmosis membranes are used e.g. in seawater desalination, nanofiltration membranes are applied for hardness removal in water purification, and ultrafiltration membranes are used in blood dialysis and microfiltration for cold sterilization of beverages – to name only a few examples. Depending on what is best suited for the specific separation process, membranes are available in different geometries: as tubular, flat sheet, spiral wound or hollow fiber configurations. Polymer-based membranes are applied in the most common applications, whereas ceramic filters are used for specific filtration tasks under more aggressive conditions.
The ultimate goal of all membrane applications is to achieve optimum separation and productivity. The filter material and process conditions thus need to be selected carefully in order to achieve highest rejection and highest flux – while keeping the filtration process as economical as possible.