Preliminary study on the characteristics of FO/PRO hollow fiber membranes

• Main Author: Chen, Yunfeng.
• Other Authors: Wang Rong
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/53886
• Institution: Nanyang Technological University

With rapid development of industrialization and fast expansion in global population, there is an increasing need for sustainable energy and clean water resources. Energy crisis has become a global issue and limited access to clean water is now a great challenge for many people around the world. Osmotic process has become an attractive solution for these problems as it develops very fast in a broad variety of applications including desalination (using Forward Osmosis (FO)) and energy generation (using Pressure Retarded Osmosis (PRO)) though FO/PRO still faces many challenges. This report will firstly review the development and challenges of FO/PRO membranes and then describe the basic steps of fabrication, modifications and evaluation of PRO membranes. The main purpose of the project is to develop a thin-film composite (TFC) hollow fiber (HF) membrane that is suitable for PRO operation and conduct a series of characterization on the newly developed membrane. Polyetherimide (PEI) is selected to fabricate the membrane substrate as it has higher tensile modulus than polyether sulfone (PES), which is a common used material in current hollow fiber membrane fabrication. Interfacial polymerization technique is applied to make the selective layer on the membrane substrate. The result shows that the HF membrane is able to withstand pressure as high as 15 bars in PRO mode and produce a power density of 10.63 W/m2. The substrate is mechanically tough and has large pure water permeability (PWP) of 462.4 L m-2 h-1 bar-1. After interfacial polymerization, the TFC HF membrane has PWP of 2.01 L m-2 h-1 bar-1 and solute permeability of 0.525 L m-2 h-1. This implies low selectivity of the membrane, which may be caused by uneven pore distribution. A further improvement is needed to achieve excellent performance for PRO operation.