Interfacial synthesis of large-area ultrathin polyimine nanofilms as molecular separation membrane

Karishma Tiwari; Solagna Modak; Pulak Sarkar; Santanu Ray; Vasista Adupa; K Anki Reddy; Sumit Kumar Pramanik; Amitava Das; Santanu Karan

doi:10.1016/j.isci.2022.104027

Interfacial synthesis of large-area ultrathin polyimine nanofilms as molecular separation membrane

iScience. 2022 Mar 4;25(4):104027. doi: 10.1016/j.isci.2022.104027. eCollection 2022 Apr 15.

Authors

Karishma Tiwari^{1

2}, Solagna Modak³, Pulak Sarkar^{3

4}, Santanu Ray⁵, Vasista Adupa⁶, K Anki Reddy⁶, Sumit Kumar Pramanik^{1

4}, Amitava Das^{1

7}, Santanu Karan^{3

4}

Affiliations

¹ Analytical and Environmental Science Division and Centralized Instrument Facility, CSIR-Central Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar, Gujarat 364002, India.
² Department of Chemistry, School of Basic & Applied Sciences, Galgotias University, Greater Noida, Uttar Pradesh 203201, India.
³ Membrane Science and Separation Technology Division, CSIR-Central Salt and Marine Chemicals Research Institute, G.B. Marg, Bhavnagar, Gujarat 364002, India.
⁴ Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India.
⁵ School of Environment and Technology, University of Brighton, Brighton BN2 4GJ, UK.
⁶ Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India.
⁷ Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India.

Abstract

Thin film membranes of covalent organic frameworks are promising for high-permeance molecular separation. However, their synthesis needs a high temperature or longer reaction time, unsuitable for large-scale fabrication of thin film composite membranes. The ultrathin film of porous organic polymers as a separation layer of the composite membrane could be a close alternative to COF membranes. Here we report transition metal ion-catalyzed room temperature fabrication of the ultrathin (≈12 nm) polyimine nanofilms via interfacial polymerization of melamine and triformylphloroglucinol onto hydrolyzed polyacrylonitrile support within a short reaction time. Composite membranes exhibit high water permeance (≈78 L m^-2 h^-1 bar^-1), high rejection (99.6%) of brilliant blue R (825.9 g mol^-1), low rejection of NaCl (≈1.8%) and Na₂SO₄ (≈17%), and enable efficient molecular separation. The role of metal ion catalysts for large-area fabrication of the ultrathin polyimine nanofilm membranes used for molecular separation is demonstrated.

Keywords: Materials sciences; Membranes; Nanotechnology.