Ammoniated-driven green synthesis of charged polyoxometalate supported ionic liquids for exceptional heavy metal remediation in actual industrial wastewater.

Reducing toxic metal concentrations to extremely low levels has long posed a challenge. Polyoxometalate supported ionic liquids (POM-SILs) offer significant potential for advanced water remediation, but their application is limited by complex preparation, toxic solvents, and poor stability due to leaching, compromising sustainability. We introduced a sustainable approach for selectively removing Pb(II) in complex electroplating wastewater using charged POM-SILs composite, synthesized by directly grafting lacunary Keggin ions ([α-SiWO], SiW) onto charged ammoniated polystyrene via a straightforward, solvent-free process. These POM-SILs featured monodisperse nanoclusters (<5 nm) in a cross-linked polymer matrix, ensuring optimal site accessibility and enhanced stability with negligible leaching. They achieved exceptional Pb(II) selectivity, boasting a distribution coefficient (K) of 23,605 mL g-over 120 times greater than conventional ion-exchange resins-and a Pb(II) removal efficiency exceeding 97.6%, even in high-salinity, diverse heavy metal environments. They reached a large Q value of 0.371 mg g, effectively treating up to 2,200 liters of wastewater per kg composite, reducing Pb(II) concentrations to below 0.01 mg L, meeting drinking water standards. This method marks a substantial advancement in heavy metal remediation, offering an efficient and sustainable solution for industrial wastewater treatment.