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Enhancing forward osmosis : Practical aspects and development of binary draw solutions

Suleman, Muhammad LU (2025)
Abstract
Forward osmosis (FO) and membrane distillation (MD) have emerged as promising processes for seawater desalination. One of the key factors influencing the FO process is the selection of a suitable draw solution (DS), which should exhibit high osmotic pressure and easy regeneration through a secondary process such as MD. Thermo-responsive polymers having ethylene oxide (EO) and propylene oxide (PO) as hydrophilic and hydrophobic units respectively, represent a special class of draw solutes for the FO process. The aim of the present study is to experimentally analyse and enhance the performance of the FO process while using different commercially available copolymers as draw solutes. In this work, three different commercially available... (More)
Forward osmosis (FO) and membrane distillation (MD) have emerged as promising processes for seawater desalination. One of the key factors influencing the FO process is the selection of a suitable draw solution (DS), which should exhibit high osmotic pressure and easy regeneration through a secondary process such as MD. Thermo-responsive polymers having ethylene oxide (EO) and propylene oxide (PO) as hydrophilic and hydrophobic units respectively, represent a special class of draw solutes for the FO process. The aim of the present study is to experimentally analyse and enhance the performance of the FO process while using different commercially available copolymers as draw solutes. In this work, three different commercially available thermo-responsive polymers - Unilube® 50MB-26, Polycerin® 55GI-2601 and Pluronic® L-35 - were evaluated as draw solutes for the FO process. Synthetic seawater containing 3.5 wt.% NaCl was used as the feed solution (FS). Initially, a series of experiments were conducted to evaluate the effect of polymer type and their concentration on the FO water flux. The experimental findings indicated that the FO water flux and percent water recovery increase with the polymer concentration. Additionally, a novel approach was established where binary DSs composed of an inorganic salt and a copolymer were introduced to enhance the FO performance. Inorganic salts such as MgCl2, CaCl2 and NaCl were used to prepare the binary DSs. It was confirmed that the binary DSs synergistically combined thermo-responsive and ionic properties, improving overall FO performance. The experimental results confirmed that the osmotic draw ability of the polymeric DSs increased with the addition of inorganic salts. Particularly, the binary DS composed of 0.7M NaCl and 65 wt.% Polycerin® 55GI-2601 yielded in a higher FO water flux of 10.13 LMH, compared to the maximum water flux of 2.5 LMH using solely polymer-based DS. Overall, the proposed binary DS concept yielded higher FO flux, offering an efficient strategy for FO desalination. (Less)
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author
supervisor
organization
publishing date
type
Thesis
publication status
published
subject
publisher
Lund University
ISBN
978-91-8096-133-2
978-91-8096-132-5
project
DEmonstration of concentrated SOLar power coupled wIth advaNced desAlinaTion system in the gulf regION.
language
English
LU publication?
yes
id
00e5d28d-804c-458e-ba22-aa0e66f2484a
date added to LUP
2025-11-18 15:53:19
date last changed
2025-11-20 10:05:52
@misc{00e5d28d-804c-458e-ba22-aa0e66f2484a,
  abstract     = {{Forward osmosis (FO) and membrane distillation (MD) have emerged as promising processes for seawater desalination. One of the key factors influencing the FO process is the selection of a suitable draw solution (DS), which should exhibit high osmotic pressure and easy regeneration through a secondary process such as MD. Thermo-responsive polymers having ethylene oxide (EO) and propylene oxide (PO) as hydrophilic and hydrophobic units respectively, represent a special class of draw solutes for the FO process. The aim of the present study is to experimentally analyse and enhance the performance of the FO process while using different commercially available copolymers as draw solutes. In this work, three different commercially available thermo-responsive polymers - Unilube® 50MB-26, Polycerin® 55GI-2601 and Pluronic® L-35 - were evaluated as draw solutes for the FO process. Synthetic seawater containing 3.5 wt.% NaCl was used as the feed solution (FS). Initially, a series of experiments were conducted to evaluate the effect of polymer type and their concentration on the FO water flux. The experimental findings indicated that the FO water flux and percent water recovery increase with the polymer concentration. Additionally, a novel approach was established where binary DSs composed of an inorganic salt and a copolymer were introduced to enhance the FO performance. Inorganic salts such as MgCl<sub>2</sub>, CaCl<sub>2</sub> and NaCl were used to prepare the binary DSs. It was confirmed that the binary DSs synergistically combined thermo-responsive and ionic properties, improving overall FO performance. The experimental results confirmed that the osmotic draw ability of the polymeric DSs increased with the addition of inorganic salts. Particularly, the binary DS composed of 0.7M NaCl and 65 wt.% Polycerin® 55GI-2601 yielded in a higher FO water flux of 10.13 LMH, compared to the maximum water flux of 2.5 LMH using solely polymer-based DS. Overall, the proposed binary DS concept yielded higher FO flux, offering an efficient strategy for FO desalination.}},
  author       = {{Suleman, Muhammad}},
  isbn         = {{978-91-8096-133-2}},
  language     = {{eng}},
  note         = {{Licentiate Thesis}},
  publisher    = {{Lund University}},
  title        = {{Enhancing forward osmosis : Practical aspects and development of binary draw solutions}},
  url          = {{https://lup.lub.lu.se/search/files/233349528/Muhammad_Suleman_Licentiate_thesis.pdf}},
  year         = {{2025}},
}