title: Development of a Desalination Membrane Bioinspired by Mangrove Roots for Spontaneous Filtration of Sodium Ions.
abstract: The shortage of available fresh water is one of the global issues presently faced by humanity. To determine a solution to this problem, the survival strategies of plants have been examined. In this study, a nature-inspired membrane with a highly charged surface is proposed as an effective membrane for the filtration of saline water. To mimic the desalination characteristics of mangrove roots, a macroporous membrane based on polyethylene terephthalate is treated with polyelectrolytes using a layer-by-layer deposition method. The fabricated membrane surface has a highly negative charged ζ-potential value of -97.5 ± 4.3 mV, similar to that of the first layer of mangrove roots. Desalination of saline water using this membrane shows a high salt retention rate of 96.5%. The highly charged surface of the membrane may induce a relatively thick and stable ion depletion zone in front of the membrane. As a result, most co-ions are repelled from the membrane surface, and counterions are also rejected by virtue of their electroneutrality. The water permeability is found to be 7.60-7.69 L/m2·h, which is 10 times higher than that of the reverse osmosis desalination method. This nature-inspired filtration membrane exhibits steady desalination performance over 72 h of operation, successfully demonstrating the stable filtration of saline water. This nature-inspired membrane is applicable to the design of a small-scale, portable, and energy-free desalination device for use in third-world countries or small villages.
authors.affiliation: Department of Mechanical Engineering and ‡Industrial Technology Convergence Center, Pohang Accelerator Laboratory, Pohang University of Science and Technology (POSTECH) , San 31, Hyoja-dong, Pohang 790-784, Republic of Korea.
authors.forename: Kiwoong
authors.initials: K
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering and ‡Industrial Technology Convergence Center, Pohang Accelerator Laboratory, Pohang University of Science and Technology (POSTECH) , San 31, Hyoja-dong, Pohang 790-784, Republic of Korea.
authors.forename: Hyejeong
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering and ‡Industrial Technology Convergence Center, Pohang Accelerator Laboratory, Pohang University of Science and Technology (POSTECH) , San 31, Hyoja-dong, Pohang 790-784, Republic of Korea.
authors.forename: Jae Hong
authors.initials: JH
authors.lastname: Lim
authors.affiliation: Department of Mechanical Engineering and ‡Industrial Technology Convergence Center, Pohang Accelerator Laboratory, Pohang University of Science and Technology (POSTECH) , San 31, Hyoja-dong, Pohang 790-784, Republic of Korea.
authors.forename: Sang Joon
authors.identifier: 0000-0003-3286-5941
authors.initials: SJ
authors.lastname: Lee
keywords: desalination; layer-by-layer deposition; mangrove; membrane; nature-inspired; polyethylene terephthalate; surface ζ-potential