Forward osmosis: Definition and evaluation of FO water transmission coefficient

Kang Rong, Tian C. Zhang, Tian Li

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Forward Osmosis (FO) usually has a measured water flux (Jw,exp) much smaller than its theoretical water flux (Jw,theoretical); the discrepancy between Jw,exp and Jw,th increases at a higher theoretical osmotic pressure difference (Δπtheoretical). Such discrepancy has been explained by concentration polarization (CP) and membrane resistance, together with an osmotic reflection coefficient (σ). However, it is not clear how to link the discrepancy or σ with FO performance and process optimization in different FO systems. In this study, a FO water transmission coefficient was defined as ηWT = Jw,exp/Jw,theoretical. The procedure was developed for determining ηWT and A (water permeability coefficient) with a static FO system. Results showed the relationship between ηWT and bulk solution concentration difference as per log ηWT = a•log(CDB − CFB) + b for different FO systems. This study also evaluated the difference between σ and ηWT.

Original languageEnglish (US)
Pages (from-to)106-112
Number of pages7
JournalJournal of Water Process Engineering
StatePublished - Dec 1 2017


  • Forward osmosis
  • Osmotic pressure difference
  • Osmotic reflection coefficient
  • Transmission coefficient
  • Water permeability coefficient

ASJC Scopus subject areas

  • Biotechnology
  • Safety, Risk, Reliability and Quality
  • Waste Management and Disposal
  • Process Chemistry and Technology


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