Conversion of microfiltration membrane into nanofiltration membrane by vapour phase deposition of aluminium for desalination application

Preparation and modification of NF membrane are challenging aspects in research. In the present work, we have synthesised Polysulfone (PSf) microfiltration membrane and reduced the pore size to nano level by physical vapour deposition (PVD) of aluminium metal. Membrane pore size was reduced from micro pore to nano pore, which rejected 42.22% of NaCl from the solution with 164 L/m2h. And also water permeation decreases from 1.10324∙10−10 to the 9.141∙10−12. The SEM and AFM pictures showed the surface modification and metal deposition in the pores. The performance of the membrane was studied by dead end flow cell using 3.5% of NaCl solution, in which PVD membrane showed 42.22% of rejection with 16.4 L/m2h flux. Thermal analysis from DSC showed Tg of 265 °C. Contact angle measurement, and water uptake were also reported.

Graphical AbstractFigure optionsDownload as PowerPoint slideResearch highlights
► Polysulfone membrane with microstructures were synthesised.
► Microporous surface was converted into nanoporous surface by aluminium coating 13 using PVD method.
► PVD coated NF membrane has showed higher salt rejection, thermal stability than the uncoated membranes.
► Characterization was done using AFM, SEM, DSC, water uptake, flux and salt rejection study.