Issue 4, 2018

Emerging investigators series: a steric pore-flow model to predict the transport of small and uncharged solutes through a reverse osmosis membrane

Abstract

This study proposed a new approach to apply the steric pore-flow model to predict the rejection of eight N-nitrosamines and seven VOCs that are of great concern in potable water reuse through an RO membrane. In this approach, solute rejection is predicted by estimating the free-volume hole-size. The free-volume hole-radius was determined with pure water permeability of a membrane and a single reference compound – N-nitrosodimethylamine (NDMA) – by minimizing the variance between the experimentally obtained and calculated NDMA rejection values at the permeate flux of 20 L m−2 h−1. The obtained free-volume hole-radius of the ESPA2 RO membrane was 0.348 nm, which was larger than the value previously determined by positron annihilation lifetime spectroscopy (PALS) analysis (0.289 nm). The model incorporated with the estimated free-volume hole-radius could accurately predict the rejection of eight N-nitrosamines under a range of permeate flux (2.6–20 L m−2 h−1). The model was also validated using experimentally obtained VOC rejection values. The predicted VOC rejections at the permeate flux of 20 L m−2 h−1 were almost identical to their experimentally obtained rejections. However, VOC rejection prediction at a lower permeate flux was less accurate. Further improvement and validation of the model with a variety of trace organic chemicals is required to allow for a more accurate prediction. The model was also validated using the membrane free-volume hole-radius value previously obtained from PALS analysis. Using PALS data resulted in some over-prediction. The results suggest that additional adjustment is necessary when using data from PALS analysis for predicting the rejection of small and uncharged solutes.

Graphical abstract: Emerging investigators series: a steric pore-flow model to predict the transport of small and uncharged solutes through a reverse osmosis membrane

Supplementary files

Article information

Article type
Paper
Submitted
17 юни 2017
Accepted
15 яну 2018
First published
16 яну 2018

Environ. Sci.: Water Res. Technol., 2018,4, 493-504

Emerging investigators series: a steric pore-flow model to predict the transport of small and uncharged solutes through a reverse osmosis membrane

H. Takeuchi, H. Tanaka, L. D. Nghiem and T. Fujioka, Environ. Sci.: Water Res. Technol., 2018, 4, 493 DOI: 10.1039/C7EW00194K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements