Recycling and Reuse of a Sugar‐Based Nonionic Surfactant Enabled by Redox‐Switchable Precipitation–Dissolution

ABSTRACT Due to environmental concerns and resource waste associated with large‐scale surfactant discharge, developing efficient recycling and reuse strategies for surfactants is of great importance. Here, a novel switchable Se‐containing sugar‐based nonionic surfactant, N ‐dodecylselenosulfonylpropyl gluconamide (NDSeOPGA), is synthesized, which can be reversibly transformed between an ON state (NDSeOPGA, water‐soluble) and an OFF state ( N ‐dodecylselenolpropyl gluconamide, NDSePGA, insoluble in both water and oil) upon alternating reactions with H ₂ O ₂ and Na ₂ SO ₃ (or N ₂ H ₄ ), leading to the formation of ─SeO─ and ─Se─ moieties, respectively. This distinctive property not only enables the surfactant to behave as a conventional one for preparing micellar solutions, emulsions and microemulsions but also enables demulsification and phase separation readily. Moreover, solid NDSePGA can be recovered (over 95%) simply by filtration from solutions or demulsified oil–water systems at room temperature and reused (more than 10 cycles) through reaction with H ₂ O ₂ . This work establishes a new paradigm for developing recyclable and reusable intelligent nonionic surfactants with broad implications for green chemistry.