• • Millimeter-scale channel width (few millimeters) between hydrophilic and hydrophobic membranes enhances emulsion droplet enrichment and collision, yielding substantial increases in oil and water recovery rates compared to conventional Janus membranes with micro/nanoscale thickness.
• • The JCM achieves concurrent recovery of both water and oil from surfactant-stabilized emulsions, overcoming the fundamental limitation of uniform-wettability membranes that recover only the permeating phase while failing to retrieve retained components.
• • The hydrophilic membrane exhibits underwater superoleophobicity, enabling rapid water permeation, while the hydrophobic membrane concurrently recovers oil, achieving synchronous dual-phase separation from high-concentration-surfactant-stabilized emulsions.
• • Multistage device configurations incorporating JCMs enable multi-level strengthening of separation and recovery efficiency, providing scalable potential for real industrial emulsion separation and recovery operations.