Joule heating assisted photothermal pervaporation MWCNTs/SA-PAN@BF membrane for high-performance ethanol dehydration

Energy-efficient pervaporation (PV) membrane technology has shown significant potential for challenging liquid-liquid separations such as ethanol dehydration. However, its performance is highly temperature-dependent, and conventional bulk heating of the feed is energy-intensive and can damage membranes. To address this challenge, this study introduces an innovative strategy that synergistically combines photothermal and Joule heating within a novel PV device enabling precise and localized heating at the membrane interface. A tailored composite membrane was fabricated on polyacrylonitrile modified basalt fiber fabrics substrate, integrating carboxylated multi-walled carbon nanotubes (MWCNTs) and sodium alginate as a photothermal separation layer. The device employs a stainless-steel mesh as both a sealing gasket and a Joule heating layer, allowing targeted thermal regulation. The impacts of MWCNTs dose, applied voltage, and feed composition on ethanol dehydration performance, energy cost, as well as long-term stability, were experimentally evaluated. At 2.9 V and 1 sun, the optimal PV membrane (2 wt% MWCNTs) demonstrated a separation factor of 1313.64 and a flux of 1124.67 g m −2 h −1 for ethanol dehydration (90 wt%). The total energy consumption was reduced by over 80% compared with the traditional bulk heating process when including the energy consumption of the solar simulator and electricity. The PV membrane also maintained excellent performance during a 120-h stability test. The mechanism, cost and performance of the novel PV device were also revealed for academic and industrial interests. This work provides a novel, efficient, and sustainable pathway for advancing PV membrane separation technology.