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Abstract
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Forward osmosis desalination presents a promising solution to address water shortages in areas near brackish or
seawater sources. This study investigates the use of thermo-responsive poly(N-isopropyl acrylamide-rand‑sodium
acrylate) microgels as innovative draw agents for forward osmosis desalination. The drawing ability and
responsiveness of these microgels are significantly influenced by the charged comonomer content. Unlike bulk
hydrogels, these microgels, owing to their core-shell morphology, maintain thermo-responsivity even at higher
comonomer content. Incorporating graphene oxide as a light absorber allows for partial heating, required to
reach the transition temperature, to be obtained using UV light radiation. In forward osmosis, microgels can be
used either in a dried state or as a concentrated aqueous dispersion. A sample with 25 mol% charged units
achieved a balance between water flux and responsiveness. It reached fluxes of 2.84, 4.79 and 4.39 L⋅m 2⋅h 1 for
the dried state, 40 wt% and 20 wt% dispersions, respectively, when tested with 5 g⋅L 1 brackish water.
Furthermore, a 40 wt% dispersion drew 35 g⋅L 1 seawater at a flux of 1.36 L⋅m 2⋅h 1. This sample, which
contains graphene oxide, exhibited a volume phase transition temperature at 41 ◦C that can be achieved through
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