Synergistic Joule‐Solar Heating Approach With Emulated Cascading Design to Boost Performance in Membrane Distillation

Treating complex wastewater requires advanced desalination technologies that can overcome the performance limitations of conventional methods. This study proposes a multi‐energy cooperative utilization strategy for surface heating membrane distillation (SHMD) using a dual‐functional composite heating membrane. The prepared NF@h‐BN@O‐MWCNTs membrane integrates the functions of a heater and a spacer, enabling complementary and synergistic utilization of electrical and solar energy. Under combined energy input, the single‐stage system achieved a water flux of 14.0 kg m − 2 h − 1 and a heat utilization efficiency (HUE) of 0.31, while maintaining a stable ion rejection rate of > 99.99% for both scaling‐prone and high‐salinity feed solutions. Moreover, the system demonstrated stable heating characteristics during continuous operation for over 60 h. By emulating a three‐stage cascade system with sensible heat recovery, the water flux in the third stage was further increased to 25.4 kg m − 2 h − 1 under an operating temperature of 80°C, and the overall average HUE reached 0.48, highlighting the great potential of heat recovery in SHMD configurations. This work offers insights into material design, multi‐energy synergy, and heat recovery strategies for SHMD systems, providing a feasible pathway toward their future application in sustainable water treatment.