Polyamide nanofilms with linearly-tunable thickness for high performance nanofiltration

• Published in: Journal of membrane science Vol. 627; p. 119142
• Main Authors: Zhu, Cheng-Ye, Liu, Chang, Yang, Jing, Guo, Bian-Bian, Li, Hao-Nan, Xu, Zhi-Kang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2021
• Subjects: Desalination; Interfacial polymerization; Nanofilm; Nanofiltration; Polyamide membrane; Interfacial polymerization; Nanofilm; Nanofiltration; Polyamide membrane; Desalination
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2021.119142

Polyamide composite membranes synthesized by conventional interfacial polymerization (IP) have attracted much attention for desalination to overcome the water shortage crisis. A big challenge is remained to desirably tune the thickness of polyamide nanofilms in these composite membranes by the uncontrollable IP process. Herein, we report a rational strategy to linearly regulate the nanofilm thickness from 32.3 to 5.6 nm by using glycerol as a water soluble and environment friendly additive to make the IP process controllable. The synthesized nanofilms display tuneable cross-linking degree and pore size, endowing the polyamide membranes with desirable water permeability and salt selectivity. Our membranes exhibit a rise of 51% in water permeance and keep the rejection ratio to Na2SO4 above 99.4% when the nanofilm thickness decreases from 32.3 to 15.1 nm. This strategy opens an eco-friendly and scalable avenue for synthesizing polyamide nanofilms which are deeply needed for nanofiltration, reverse osmosis and forward osmosis.
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•Polyamide nanofilm with a Linearly-Tunable thickness of 32.3 to 5.6 nm are synthesized.•The interfacial polymerization (IP) is well controlled by confining the monomer diffusion.•Glycerol is used as water soluble and environment friendly additive to make IP tunable.•The synthesized nanofilms display tunable cross-linking degree and pore size distribution.•The polyamide-based composite membranes show a 51% increase in water permeability.