Engineering morphological architecture of superhydrophobic/hydrophilic composite membrane for efficient photothermal membrane distillation

Abstract

The viability and efficacy of photothermal membrane distillation (PMD) is still uncertain due to its inherent energy-efficiency and throughput mass flux limitation. Herein, we develop a delamination-free multilayer photothermal membrane that simultaneously imparts slashed mass transfer resistance, enhanced photothermal effect and strong water-repellency by engineering morphological architecture. Using a one-step programmed dual-channel electrospinning followed by an electrostatic spraying technique, the proposed membrane is composited by a thick water-intrudable hydrophilic supporting layer, a thin hydrophobic layer, and an ultrathin Ti₃C₂T_x MXene-engineered superhydrophobic layer. It is proposed that the morphological architecture engineering could render mitigation of mass transfer resistance, firm water-repellency, and robust heat localization. Hence, in addition to superior flux of 1.27 L m⁻² h⁻¹ (inlet feed/permeate at 20/20 °C) and 15.89 L m⁻² h⁻¹ (inlet feed/permeate at 50/20 °C), prominent solar efficiency (76.34 % and 96.45 %) of the proposed composite membrane (DS15-M) also was achieved during PMD operation (1.0 kW m⁻²). Moreover, the DS15-M showcased not only robust wetting resistance and long-term consistency, but also obviously mitigated temperature polarization effect during the PMD operation. This research work emphasizes the important role of morphological architecture in rendering performance enhancement, which is a significant implication in engineering membrane architecture for PMD application.