University of Twente Student Theses


Hybrid polyPOSS‐amide Membranes for Nanofiltration

Schneider, Lynn Maria (2014) Hybrid polyPOSS‐amide Membranes for Nanofiltration.

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Abstract:There is a lack of positively charged nanofiltration (NF) membranes which enable the removal of multivalent cations such as toxic dyes, calcium or heavy metals from industrial effluents. Positively charged NF membranes are promising to improve both, separation performance and energy efficiency compared to common separation techniques used. [1] In this study, hybrid inorganicorganic polyamide NF membranes were synthesized and investigated with respect to their positive charge behavior. The hybrid and hyper‐crosslinked nature of these membranes offers outstanding thermal‐mechanical stability. The membranes were synthesized by interfacial polymerization of octaammonium polyhedral oligomeric silsesquioxane (POSS) and isophtaloyl dichloride. For the polycondensation reaction POSS molecules were activated by converting unreactive ammonium groups to primary amine groups with addition of sodium hydroxide. The concept was to change the pH of the POSS solution in the synthesis and study the effect on charge and cross‐linking. Characterization by attenuated total reflection infrared spectroscopy and x‐ray photoelectron spectroscopy showed a trend of more positive charges for lower preparation pH and similarly more cross‐linking for membranes with higher pH values. Streaming Zeta potential measurements showed isoelectric points around 8 for all membranes; indicating that all synthesized membranes were positively charged below pH 8 and that a low amount of carboxylic acid groups was present.
Item Type:Essay (Bachelor)
Faculty:TNW: Science and Technology
Subject:33 physics
Programme:Applied Physics BSc (56962)
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