Self-heating Janus separable CNT-PVA@CC/HPo-PVDF membrane coupling photothermal and electrothermal effects for high-oil resistance, high-efficiency and stable membrane distillation

Self-heating membrane distillation has emerged as a promising method for seawater desalination due to its cost-effectiveness and high efficiency membrane distillation (MD) performance. However, the single energy input (solar or electrical energy) of the current self-heating MD faces challenges such as unstable freshwater production, high energy consumption, and intolerance to oil contamination. To overcome these limitations, we develop a novel self-heating Janus membrane (CNT-PVA@CC/HPo-PVDF, MWCNT-Polyvinyl alcohol@ Carbon Cloth/ hydrophobic Polyvinylidene fluoride-hexa-fluoropropylene nanofiber membrane) that combines photothermal and electrothermal effects for local heating and efficient phase separation. Our experimental and numerical findings demonstrate that the solar and electrical energy coupled membrane distillation (SEMD) performance of the Janus membrane is influenced by working conditions. By optimizing the flow velocity (0.06 g/s) and electrical/solar energy ratio (1 sun and 0.2 W), we achieve a remarkable water flux of 4.3 kg m−2 h−1 (4.6 times larger than conventional MD) and an energy utilization efficiency of 76.32%. Furthermore, the Janus membrane exhibits excellent performance in silicone oil/saline emulsion for 60 hrs; the separable design allows replacing the hydrophobic membrane if it is contaminated, which extends the service life of the self-heating layer (CNT-PVA@CC). This study provides valuable insights for the development of low-energy, low-cost, and durable water separation technology in oil-contaminated seawater.