Situation: | The usage of membrane filtration in water treatment was rapidly increasing in the last 20 years. Despite of the rising number of applications of commercial membranes, the main drawbacks in this technology remain the formation of fouling layers. In low pressure membrane processes (micro- and ultrafiltration), mainly particles, colloids, organic macro molecule (organic fouling) and microorganisms (biofouling) lead to the formation of these layers. High pressure membrane processes like nanofiltration, are mainly affected by the adsorption of organic substances and biofouling. Measures for the reduction of fouling are ranging from the pre processing of incoming water, through the improvement of fluid dynamics within the membrane module to the physico-chemical modification of surface properties of the used materials (mainly polymers). In latter field, the present research project wants to investigate unresolved questions regarding the relationship between surface charge and resulting fouling and separation behavior. |
| Methodology: | Using ion beam enhanced deposition of metals, called plasma immersion ion implantation and deposition (PBII&D), the surface conductivity of common polymer membranes will be increased. By applying an external potential (-1.5 V to 1,5 V), these modified membranes will be examined on their fouling- and separation behavior in different aqueous solutions. The results will be compared with existing transport models (electrokinetic models) and they will be adjusted, if necessary. These findings will be used to design a model which can be used for the simulation of the separation behavior under different operation conditions. More detailed and comprehensive understanding of the interactions between surface charge of the membrane (zeta potential) and resulting fouling- and separation behavior can be utilized for “potentially controlled functionalization” of membrane surfaces.
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