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Enhancing ammonium rejection in forward osmosis for wastewater treatment by minimizing cation exchange

Enhancing ammonium rejection in forward osmosis for wastewater treatment by minimizing cation exchange
Enhancing ammonium rejection in forward osmosis for wastewater treatment by minimizing cation exchange
Ammonium permeation to draw solution (DS) is very common in forward osmosis (FO) treatment due to the negative charge nature of the membrane, which restricts the application of FO for wastewater treatment particularly with a purpose of ammonium recovery and water reuse. Membrane modification by reducing the negative charge of membrane surface could improve ammonium rejection. This study investigated ammonium rejection in the FO process by selecting DSs with different physicochemical properties. Results show an increased ammonium rejection rate with divalent cation-based DS (i.e. Mg2+) due to larger hydrated cation radius compared with monovalent cations such as Na+ under the same osmotic pressure. Non-ionic DSs such as glucose, glycine and ethanol are able to minimize ion exchange across the membrane, leading to a 98.5–100% ammonium rejection. This indicates that cation exchange is the critical factor for ammonium permeation. Real wastewater treatment such as municipal wastewater and sludge digestate liquor by FO with NaCl and glucose as DS, respectively, further confirms that minimizing cation exchange by selecting appropriate DS could significantly improve ammonium rejection, which is not negatively affected by the more complex nature of real wastewater. This study developed an alternative method by selecting appropriate DS to increase ammonium rejection. Furthermore, it shed light on the mechanism of enhanced ammonium rejection with different types of DSs, which could provide general guidance on the selection of DS from the perspective of wastewater treatment with ammonium considered.
Ammonium rejection, Draw solution, Forward osmosis, Municipal wastewater, Nutrient recovery, Thin-film composite
0376-7388
Almoalimi, Khaled
69df5031-815b-47ea-b014-d7975dfa7829
Liu, Yongqiang
75adc6f8-aa83-484e-9e87-6c8442e344fa
Almoalimi, Khaled
69df5031-815b-47ea-b014-d7975dfa7829
Liu, Yongqiang
75adc6f8-aa83-484e-9e87-6c8442e344fa

Almoalimi, Khaled and Liu, Yongqiang (2022) Enhancing ammonium rejection in forward osmosis for wastewater treatment by minimizing cation exchange. Journal of Membrane Science, 648, [120365]. (doi:10.1016/j.memsci.2022.120365).

Record type: Article

Abstract

Ammonium permeation to draw solution (DS) is very common in forward osmosis (FO) treatment due to the negative charge nature of the membrane, which restricts the application of FO for wastewater treatment particularly with a purpose of ammonium recovery and water reuse. Membrane modification by reducing the negative charge of membrane surface could improve ammonium rejection. This study investigated ammonium rejection in the FO process by selecting DSs with different physicochemical properties. Results show an increased ammonium rejection rate with divalent cation-based DS (i.e. Mg2+) due to larger hydrated cation radius compared with monovalent cations such as Na+ under the same osmotic pressure. Non-ionic DSs such as glucose, glycine and ethanol are able to minimize ion exchange across the membrane, leading to a 98.5–100% ammonium rejection. This indicates that cation exchange is the critical factor for ammonium permeation. Real wastewater treatment such as municipal wastewater and sludge digestate liquor by FO with NaCl and glucose as DS, respectively, further confirms that minimizing cation exchange by selecting appropriate DS could significantly improve ammonium rejection, which is not negatively affected by the more complex nature of real wastewater. This study developed an alternative method by selecting appropriate DS to increase ammonium rejection. Furthermore, it shed light on the mechanism of enhanced ammonium rejection with different types of DSs, which could provide general guidance on the selection of DS from the perspective of wastewater treatment with ammonium considered.

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Accepted/In Press date: 12 February 2022
e-pub ahead of print date: 14 February 2022
Published date: 15 April 2022
Additional Information: Funding Information: The authors thank the King Saud University for the scholarship provided to Khaled Almoalimi for his PhD study at the University of Southampton, UK. Publisher Copyright: © 2022 Elsevier B.V. Copyright: Copyright 2022 Elsevier B.V., All rights reserved.
Keywords: Ammonium rejection, Draw solution, Forward osmosis, Municipal wastewater, Nutrient recovery, Thin-film composite

Identifiers

Local EPrints ID: 455328
URI: http://eprints.soton.ac.uk/id/eprint/455328
ISSN: 0376-7388
PURE UUID: d2639e1a-4f24-4878-a2cf-f7945486d325
ORCID for Yongqiang Liu: ORCID iD orcid.org/0000-0001-9688-1786

Catalogue record

Date deposited: 17 Mar 2022 17:31
Last modified: 23 Jul 2022 02:07

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Contributors

Author: Khaled Almoalimi
Author: Yongqiang Liu ORCID iD

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