Synthesis of Sub-10 nm Two-Dimensional Covalent Organic Thin Film with Sharp Molecular Sieving Nanofiltration
Ikhlas Gadwal1, Guan Sheng1, Roshni Lilly Thankamony1
1Advanced Membranes and Porous Materials Center, Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology , Thuwal 23955-6900 , Saudi Arabia.
Abstract:
We demonstrated here a novel and facile synthesis of two-dimensional (2D) covalent organic thin film with pore size around 1.5 nm using a planar, amphiphilic and substituted heptacyclic truxene based triamine and a simple dialdehyde as building blocks by dynamic imine bond formation at the air/water interface using Langmuir-Blodgett (LB) method. Optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM), all unanimously showed the formation of large, molecularly thin and free-standing membrane that can be easily transferred on different substrate surfaces. The 2D membrane supported on a porous polysulfone showed a rejection rate of 64 and 71% for NaCl and MgSO4, respectively, and a clear molecular sieving at molecular size around 1.3 nm, which demonstrated a great potential in the application of pretreatment of seawater desalination and separation of organic molecules.
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