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(711c) Micro-Deformation in Polyethersulfone Inner-Selective Thin Film Composite Hollow Fiber Membranes Under High Hydraulic Pressures in Pressure Retarded Osmosis Process

Authors: 
Gai, W., National University of Singapore
Li, X., National University of Singapore
Xiong, J., National University of Singapore
Wan, C. F., National University of Singapore
Chung, T. S., National University of Singapore

Micro-deformation in Polyethersulfone
Inner-selective Thin Film Composite Hollow Fiber Membranes under High Hydraulic
Pressures in Pressure Retarded Osmosis Process

Wenxiao Gai, Xue Li, Jun Ying Xiong,
Chun Feng Wan, Tai-ShungChung *

Department of Chemical and
Biomolecular Engineering, National University of Singapore, 4 Engineering Drive
4, Singapore 117585, Singapore

*
Corresponding author: Tel.: +65 6516 6645. E-mail: chencts@nus.edu.sg

Abstract

Pressure retarded
osmosis (PRO) is one of the promising methods to harvest the osmotic energy ,
which is a clean and renewable candidate to mitigate the dependence of mankind
on non-renewable and environmentally detrimental fossil fuels, by separating
the two solutions using a semi-permeable membrane. Recently, lots of thin film
composite (TFC) hollow fiber (HF) membranes have been developed for PRO application
because of their self-support configuration and high packing density properties.
This work may be one of the first attempts to systematically investigate (1) the
micro-deformation of the inner-selective TFC HF membranes under high hydraulic pressures for osmotic
power generation and (2) the evolution of permeation properties with the increased
hydraulic pressures applied in the lumen side from 0 to 20 bar. Experimental
results show that pre-stabilization at 20 bar close to the burst pressure of the
polyethersulfone (PES) TFC HF membranes could improve the water flux and power
density dramatically due to the increased membrane surface area, stretched
polyamide selective layer and decreased membrane structure parameter. It was also
proved by the intermittent cycle tests that the enhancement of water flux and
power density is sustainable after pre-stabilization at 20 bar without
compromising the selectivity.  These results may provide significant technical
implications to design desirable membranes for PRO application and maximize the
output of the PRO process.