|Funding:||Deutsche Forschungsgemeinschaft (DFG)|
|Duration:||01.01.2021 - 01.01.2024|
Ultraﬁltration (UF) membranes are used in water treatment due to their high permeate ﬂux at low pressures and compact size. However, UF membranes suffer from fouling and are not able to remove problematic organic substances as natural organic matter (NOM) from raw water. So far, energy-intensive nanofiltration (NF) membranes are applied to reduce NOM concentrations. A new approach to overcome this problem are electrically conductive ultrafiltration membranes, which have been developed in recent years. They have been mainly used for fouling mitigation and rejection enhancement during filtration of natural organic matter (NOM). Due to the negative surface charge of NOM, a repulsive force is induced when a negative electrical potential is applied to the membrane. In new electrically conductive membranes, positive electrostatic potential is applied to the membrane surface in order to achieve electrosorption of negative charged NOM.
Commercially available porous membranes will be modified in order to generate an electrical conductive surface by coating the membrane (e. q. with an ultra-thin layer of metal or other materials). During dead-end filtration of natural raw water (e.g. ground or surface water) a positive potential will be applied to the membrane surface to enhance the removal of NOM. When electrosorptive removal capacity is exhausted, the applied potential will be reversed to a negative potential in order to desorb the NOM adsorbed on membrane and regenerate it for further electrosorptive filtration. By this, electrosorptive dead-end UF reaches the NOM removal rates of NF membranes, which are frequently operated in cross-flow mode. The Institute of Polymer research of Helmholtz-Zentrum Geesthacht (HZG) is involved in the project.
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