3. Conclusion
In conclusion, a new type of functional photothermal materials
(MF@HPB-PPyn-OA) with controllable interfacial
hydrophilicity-hydrophobicity are successfully designed and obtained by
the self-assembly of HPB, OA and PPy on the 3D porous MF surface for
high-efficiency water evaporation and complete salt-water separation of
high-salinity samples. By virtue of the unique spatial separation
structure of the hydrophilic region HPB and hydrophobic region OA, the
hydrophilic-hydrophobic interface of the 3D porous SVG materials is
managed for the first time to balance the contradiction between
efficient water evaporation and salt crystallization. Meanwhile, the
strong brine convection effect formed between the nano-water channels on
the hydrophilic region and the microporous channels of
MF@HPB-PPyn-OA further enhances the anti-salt fouling
performance. Among them, MF@HPB-PPy10-OA can operate
continuously and stably for over 100 h at ultrahigh evaporation rate of
3.3 kg m-2 h-1 under 1 sun while
surface free of salt crystallization for desalination of high-salinity
brine (10 wt%). More notably, MF@HPB-PPy10-OA
accomplishes the complete salt-water separation of 10 wt% brine,
yielding up to 3.3 kg m-2 h-1 and
96.5% evaporation rate and salt harvesting efficiency, which realizes a
record-high for high salinity or local salt crystallization systems.
Apart from the high-efficiency performance,
MF@HPB-PPy10-OA also holds the advantages of simple
process, low-cost, and batch manufacturing, indicating broad
applicability in the fields of solar humidification, salt extraction
from seawater and wastewater purification. This study not only
demonstrates the vital role of interfacial hydrophilic-hydrophobic
engineering for high-efficiency, salt-resistant and sustainable
operation, but also advances the development of novel HPB-based SVG
functional materials for seawater desalination and zero liquid
discharge.