Performance evaluation of polyamide TFC membranes: Effects of free volume properties on boron transport

Sung Jo Kim, Doseon Han, Hye Weon Yu, Brian E. O'Rourke, Yoshinori Kobayashi, Ryoichi Suzuki, Moonhyun Hwang, In S. Kim

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


To comprehensively investigate the correlation between free volume properties (size and distribution) in the interior of polyamide (PA) active layer and mass transport mechanism, six polyamide thin film composite (TFC) membranes were characterized using positron annihilation lifetime spectroscopy (PALS). In case of pressurized filtration conditions, the rejection rate of boron across all PA membranes was found to be inversely proportional to the free volume size. The more boron transport occurred at the membrane containing larger free volume. In addition, the transition of the neutral boron transport mechanism from convection to diffusion was found to occur at a membrane free volume radius around 0.275 nm within the applied pressure range (2 and 10 bar), as verified by PALS and the dimensionless Peclet number. We believe that mass transport mechanism transition from convection to diffusion is caused by the compression of polyamide active layer due to applied hydraulic pressure (10 bar), resulting in lowering the convective mass transport pathway inside polyamide active layer. These membrane free volume size criteria and experimental filtration results may subsequently be used as new design guidelines for the development of high boron rejection polyamide TFC membranes having a low energy consumption.

Original languageEnglish
Pages (from-to)104-114
Number of pages11
Publication statusPublished - 2018 Apr 15


  • Boron transport
  • Free volume
  • Membrane pore
  • Polyamide active layer
  • Positron annihilation lifetime spectroscopy (PALS)

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Water Science and Technology
  • Mechanical Engineering


Dive into the research topics of 'Performance evaluation of polyamide TFC membranes: Effects of free volume properties on boron transport'. Together they form a unique fingerprint.

Cite this