Modular design of solar-thermal nanofluidics for advanced desalination membranes

Abstract

Water nanofluidics in confined channels has endowed pressure-driven separation membranes with superior permeability. However, the nanofluidics effect in solar-thermal steaming materials is hindered by discrete heat absorbers and nanochannels. Here we report the modular design of solar-thermal nanofluidics membranes by integrating carbon nanotubes and metal–organic frameworks (MOFs) through a self-crosslinkable polyelectrolyte under mild conditions. The uniformly dispersed carbon nanotubes permit efficient sunlight absorption for localized heat transfer. Subsequently, water molecules form clusters in the nanochannels of MOF nanoparticles, and the water vaporization enthalpy was reduced by 45% due to water nanofluidics, which was confirmed by both simulation and thermal characterization. As such, mixed matrix membranes exhibited exceptional combination of high evaporation rates (2.56 kg m⁻² h⁻¹, under 1 sun irradiation) with stability versus recycling, solvents, solution pH (1, 13) and oil fouling. These findings provide a modular design of MOF evaporators featuring high performance arising from solar-thermal nanofluidics.