Highly efficient heavy metal remediation from multiple scenarios actual industrial wastewaters by ultralong sub-5 nm polyoxometalate ionic liquid fibrilization strategy.

Reducing heavy metals to trace levels in actual complex industrial wastewater remains a major challenge due to high salinity, organic interferences, and multi-metal competition. Ionic liquids (ILs) are promising for metal remediation but suffer from limited active site accessibility and slow diffusion in conventional immobilized nanocomposites. Here, a scalable fibrillation strategy is developed based on precise molecular spatial confinement self-assembly, wherein lacunary Keggin-type SiW11 clusters integrate with amphiphilic cations to yield one-dimensional IL nanofibrils. These IL nanofibrils feature ultrathin diameters (< 5 nm), high aspect ratios (> 103), and strong negative zeta potentials (< -30 mV), enabling full active site exposure and rapid heavy metal transport. As a result, they achieve > 96.8 % removal efficiency under high salinity and multi-metal competition, with a Pb(II) distribution coefficient (Kd) of 28,877.5 mL/g-over 490-fold higher than commercial sulfonated polystyrene resins. Ultrafast kinetics were observed, with pseudo-second-order rate constants (k2) 6-10 times greater than those of supported ILs. In continuous-flow tests across five real industrial sites, the nanofibrils demonstrated purification capacities of 3678-6940 L/kg, consistently reducing effluent Pb(II) below 0.1 mg/L (GB21900-2008, China). Charged IL nanofibrils can be easily regenerated with negligible performance loss and at minimal cost, thereby constituting a robust and scalable platform for the deep extraction of heavy metals from real complex effluents. More broadly, this fibrillar IL construction strategy unlocks programmable interfacial chemistry for advanced wastewater treatment systems.