Composite membranes with surface-modifying macromolecules for halogenated hydrocarbons removal from water in membrane extraction process

Abstract

Flat sheet composite polysulfone (PSf) membranes blended with surface-modifying macromolecules (SMM) were prepared, characterized, and tested for halogenated hydrocarbons (HHC) (i.e. trichloroethylene, TCE) permeation and separation from water in an extractive membrane system. The fluorine end groups in SMMs facilitated its migration towards the membrane surface during membrane casting, whereas the polydimethylsiloxane component rendered the SMM organophilic which improved the surface affinity of the composite membrane towards TCE. Polydimethylsiloxane content in SMM, SMM content in PSf, and air-exposure of the casted blend solutions before membrane formation were found critical in obtaining an effective composite membrane. The presence of a selective SMM layer on the membrane surface was confirmed via contact angle measurement, Fourier-transform infrared spectrometry analysis, and field emission-scanning electron microscope. The most effective composite membrane (PSf with 15 wt% H-SMM and air exposed for 5 min before phase inversion) exhibited TCE flux values ranging between 640 and 1790 mg/m²h when fed with TCE concentrations between 30 and 105 mg/L. Overall results demonstrate the potential use of the composite extractive membrane for the removal of hydrophobic organic contaminants like HHCs from aqueous streams.

Keywords:

• Composite membrane
• Extractive membrane
• Halogenated hydrocarbon
• Surface-modifying macromolecule
• Water purification

Acknowledgement

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Ministry of Science, ICT & Future Planning (No. 2012R1A2A1A01009683) and the Ministry of Education (grant number 2009-0093816).

Notes

Presented at the 5th IWA-ASPIRE Conference 8–12 September 2013, Daejeon, Korea