Tunable
gating graphene oxide (GO) membranes with high water permeance
and precise molecular separation remain highly desired in smart nanofiltration
devices. Herein, bioinspired by the filtration function of the renal
glomerulus, we report a smart and high-performance graphene oxide
membrane constructed via introducing positively charged
polyethylenimine-grafted GO (GO-PEI) to negatively charged GO nanosheets.
It was found that the additional GO-PEI component changed the surface
charge, improved the hydrophilicity, and enlarged the nanochannels.
The glomerulus-inspired graphene oxide membrane (G-GOM) shows a water
permeance up to 88.57 L m–2 h–1 bar–1, corresponding to a 4 times enhancement
compared with that of a conventional GO membrane due to the enlarged
confined nanochannels. Meanwhile, owing to the electrostatic interaction,
it can selectively remove positively charged methylene blue at pH
12 and negatively charged methyl orange at pH 2, with a removal rate
of over 96%. The high and cyclic water permeance and highly selective
organic removal performance can be attributed to the synergic effect
of controlled nanochannel size and tunable electrostatic interaction
in responding to the environmental pH. This strategy provides insight
into designing pH-responsive gating membranes with tunable selectivity,
representing a great advancement in smart nanofiltration with a wide
range of applications.
Offshore oil spills, industrial oily wastewater, and domestic oil pollution are some of the most serious global challenges, leading environmental causes of morbidity and mortality. Nanofiber membrane materials manufactured via...
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