Up to now, developing nanofiltration (NF) membranes with
outstanding
salt rejection and excellent permeability has become a crucial challenge.
In this work, thin film composite (TFC) membranes containing two-dimensional
nanochannels were successfully prepared using 2D Mg(OH)2 nanosheets as sacrifice templates. The nanosheets were dispersed
in trimethyl chloride/n-hexane and then incorporated
into the polypiperamide layer by interfacial polymerization. The introduction
of Mg(OH)2 and etching with H2SO4 (pH = 3) can increase membrane flux without rejection loss. The
2D nanochannels provided additional transport routes for water molecules.
The prepared TFC membranes formed a root-like morphology on the surface,
along with a thinner selective layer and lower cross-linking, contributing
to the increase in water flux. Therefore, the desalination performance
of etched membranes was better than control membranes. The membrane
made from 0.05 wt % Mg(OH)2 shows a Na2SO4 rejection of 98.25%, and water flux increases by 72.8%. The
TFC membranes prepared in this work have high stability in operation
and have even better antifouling properties. This approach provides
a new strategy for the preparation of high-performance NF membranes,
which is applied in seawater desalination.