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Ultrathin Nanofiltration Membrane from Confined Polymerization within the Nanowire Network for High Efficiency Divalent Cation Removal
journal contribution
posted on 2019-09-16, 12:36 authored by Zhenyi Wang, Wangxi Fang, Feng Zhang, Yuzhang Zhu, Jian JinMembranes
with high permeance and high rejection for di- and multivalent
cation removal are highly desired for efficient brackish water and
industrial water treatment. In this work, we report a facile strategy
for constructing ultrathin nanofiltration (NF) membranes by in situ
cross-linking of amine which is confined in a network film. The network
made of single-walled carbon nanotubes (SWCNTs) serves as a framework
for poly(ethylene imine) (PEI) to attach and stay, facilitating the
formation of a polyamine (PA) layer with high quality and controlled
thickness. Benefiting from the ultrathin thickness of the SWCNT network
(∼31 nm), an active layer (∼34 nm thick) comes with
a high permeance of 27 L m–2 h–1 bar–1 along with a high rejection of 97% to MgCl2, 2–5 times higher than the NF membranes with the same
high rejection for MgCl2 reported so far. In addition,
the SWCNT-interpenetrated PA structure endows the ultrathin NF membrane
with good operational stability. This work demonstrates the capability
to control the position, thickness, and even quality of the PA layer
by using a confined framework and provides a feasible strategy for
the fabrication of highly permeable ultrathin NF membranes with a
reinforced active layer.