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.
Bibliographical noteFunding Information:
This research was financially supported by the Creative Research Initiative (Diagnosis of Biofluid Flow Phenomena and Biomimic Research) of the National Research Foundation (NRF) of Korea (Contract Grant Number 2008-0061991). We thank H. Kwon and Prof. G. Lim from POSTECH in Korea for their assistance with design of filtration experiments.
© 2016 American Chemical Society.
- layer-by-layer deposition
- polyethylene terephthalate
- surface ζ-potential
ASJC Scopus subject areas
- General Materials Science
- General Engineering
- General Physics and Astronomy