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Novel Draw solutes for Forward Osmosis (FO)

Technology #12195n

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Prof. Chung Tai Shung, Neal
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Ms Yong Yoke Ping (
Manager (65)66011680
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US Patent Pending
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Tech Offer 12195N Novel Draw Solutes for FO [PDF]


•  Forward Osmosis


Patent Pending


•  Licensing

•   Partnership for further development


•  NUS Ref: 12195N

•   Yong Yoke Ping (tel.: 65-660 11680)

•   Email: ,

•   Primary Inventor: Prof. Chung Tai Shung, Neal


·  Very low reverse salt flux (~0.1 g m-2h-1)  è less cost in replenishing draw solute

·  Higher water flux than NaCl at the same molar concentration è higher productivity

·  Can be recovered by nanofiltration

Technology Overview

Osmosis is defined as the net movement of water across a selectively permeable membrane driven by a difference in osmotic pressure across the membrane. Unlike reverse osmosis, it is a low energy process which has potential to be used on its own or to be combined with existing processes for desalination, concentration, dilution, etc.

Barriers to widespread use of FO technologies are (1) the lack of a suitable high flux membrane as well as (2) the unavailability of a draw solute which requires little replenishment (due to reverse salt flux across the membrane) during operation and easy to separate from the permeate stream.

This technology relates to a novel draw solute for forward osmosis which has a very low reverse salt flux as well as a higher water flux across the membrane, compared to NaCl.

Below are some results of the experimental runs in the PRO mode (active layer facing draw solute)

Figure 1: Comparison of (a) Water flux of draw solute and NaCl and (b) Reverse flux of draw solute and NaCl, using DI water as the feed solution in the PRO mode.

For every liter of water recovered from the FO process, less than 0.003g of the draw solute diffuses to the feed stream.

In addition, nanofiltration can be used to separate the draw solute from the permeate stream. Results are shown below.

Figure 2: Results of using nanofiltration to regenerate the draw solute at 10 bar

Development Status

The draw solute has been tested and proven in laboratory scale setups. The draw solute can be regenerated by nanofiltration or membrane distillation. The draw solute should be paired with a high flux membrane for an application specified by industry to explore its potential to the fullest.