Selective hydrophilization of the permeate surface to enhance flux in membrane distillation

This paper reports the development of novel hydrophilized membrane for water desalination using direct contact membrane distillation (DCMD). The permeate side of a porous polytetrafluoroethylene (PTFE) membrane on polypropylene (PP) support was hydrophilized by chemical treatment with oxidizing agents to enhance the rapid condensation and removal of permeated vapors. Depending upon the process conditions, permeate flux was as high as 61 L/m² h, and as much 73% higher than an unmodified membrane. 58% increase in overall mass transfer coefficient was also observed with the hydrophilized membrane. In short, hydrophilization of membrane surface showed enhanced flux at lower temperature, making this a more energy efficient process.