Silicone based membranes for organic solvent nanofiltration

  • Silikonbasierte Membranen für die organophile Nanofiltration

Lazar, Marina; Wessling, Matthias (Thesis advisor); Benes, Nieck E. (Thesis advisor)

Aachen (2015, 2016)
Dissertation / PhD Thesis

Dissertation, RWTH Aachen, 2015


One of the polymers enabling successful application of organic solvent nanofiltration membranes is silicone or more precisely poly(organosiloxane). This thesis includes a study on silicone based membranes, as to their chemistry, their separation performance in organic solvents and influence of introduced functional groups. The performance of a silicone based membrane was first compared to membranes based on polyimide and PIM-1 (polymers of intrinsic microporosity). The tests were made in heptane and acetone to underlie the difference in the separation properties of the tested membrane materials. Further, the development of a predictive model for multicomponent mass transport through a silicone membrane was made. The applied modelling approach can be differentiated in a Flory-Rehner based model to estimate membrane swelling and a simplified Maxwell-Stefan mass transport model. The prediction accuracy of developed modelling approach was compared to the measured values for eleven pure solvents. The predicted values of styrene oligomer rejection curves in these solvents were also compared to the measured values. The production and performance of composite membranes made from acrylatefunctional and epoxy-functional silicones in styrene oligomer/heptane mixture were also investigated. Next to this, a performance comparison in several solvents of acrylate-functional, epoxy-functional and a commercially available silicone based membrane was made. The measured results were used together with modelling approach to determine membrane specific parameters and their relevance in accurate predicting of the measured data.