Integrating a Self-Floating Janus TPC@CB Sponge for Efficient Solar-Driven Interfacial Water Evaporation

Solar-driven
photothermal interfacial evaporation is considered
as one of the most promising strategies in seawater desalination and
wastewater treatment. In desalination, evaporation efficiency and
salt resistance are regarded as two inter-constraint measures. Thus,
it is still challenging to fabricate solar evaporators with both high
evaporation efficiency and excellent salt resistance. In the present
work, a self-floating Janus sponge composed of hydrophobic carbon
black (CB) coating and hydrophilic porous thermoplastic polyurethane-carbon
nanotube (TPC) nanofibrous substrate (TPC@CB) is fabricated via a
simple electrospinning and gas templating expansion method. Attributing
to the unique trilaminar functional architecture: the upper superhydrophobic
solar-absorption coating, the intermediate ultrathin heat localization
layer, and the lower cellular thermal insulation layer, the Janus
TPC@CB sponge exhibits high evaporation efficiency (1.80 kg m–2 h–1 with an energy efficiency of
97.2% under 1.0 solar irradiation) and outstanding salt resistance
ability. Moreover, zero liquid discharge in salt-containing wastewater
treatment is realized using the Janus TPC@CB sponge as a solar-driven
photothermal medium. This work provides a promising approach to seawater
desalination and wastewater treatment.