Preparation and Characterization of Hydrophobic/Hydrophilic Polyethersulfone Composite Membrane for Application in Direct Contact Membrane Distillation

Membrane distillation (MD) is a non-isothermal membrane separation process. In this work, a porous hydrophobic/hydrophilic composite membrane prepared by the phase inversion method in one casting step from a polymer solution containing a hydrophilic polymer and a fluorinated surface modifying macromolecule (SMMs). The membranes were characterized using a characterization techniques including the measurement of the liquid entry pressure of water (LEPw), scanning electronic microscopy (SEM) and contact angle measurement. Furthermore, the membranes were tested by DCMD for desalination of 0.5 M NaCl solution. It was found that increasing the polymer concentration decreased the permeate flux of the porous composite hydrophobic/hydrophilic membranes since the liquid entry pressure of water increased. According to the results, SMMs migrated to the surface and effectively increased the surface hydrophobicity of PES membranes when blended. Increase in liquid entry pressure of water (LEPw) with an increase of surface contact angle was also observed.