Molecularly Engineered Sisal Fibers with Programmable Interfaces for Efficient Separation of Complex Emulsions and Multipollutants

Purifying surfactant-stabilized oily wastewater remains significant challenge, as conventional demulsifiers frequently fail to disrupt complex emulsions stabilized by multiple surfactant types. Herein, we developed an innovative molecular engineering strategy that constructs phytic acid-crosslinked β-cyclodextrin (PA-cl-β-CD) networks on sisal fibers (SFs) through a facile one-step process, creating an eco-friendly separation material (SFs@PA-cl-β-CD) with dynamically tunable surface wettability and interfacial properties. This biomass-based material exhibits remarkable versatility, achieving universal high separation efficiency (>99%) for diverse oil-in-water emulsions regardless of surfactant types (cationic, anionic, or nonionic) through molecularly programmable surface wettability control. The hierarchical architecture of this material combines the superior interfacial activity of the PA-cl-β-CD coating with the macroporous structure of SFs, enabling synergistic demulsification and adsorption functionality. Beyond oil-water separation, this material demonstrates multifunctional purification capabilities toward multipollutants, simultaneously removing harmful heavy metals (99.6% for Ni²⁺ and 98.8% for Mn²⁺) and dyes (~100% for methylene blue). This material maintains stable performance over multiple reuse cycles while exhibiting enhanced safety with superior flame-retardant properties (70% reduced flammability), enabled by the PA-cl-β-CD coating. This sustainable biomass-based platform successfully integrates molecular design with macroscopic functionality, achieving comprehensive remediation of emulsion wastewater while overcoming key limitations of conventional methods.