Porous Poly(Ionic Liquid) Membranes as Efficient and Recyclable Absorbents for Heavy Metal Ions

Abstract

Heavy metal ion pollution has become a serious environmental problem. Herein, this study reports the synthesis of poly(ionic liquid) (PIL) membranes via in situ photo-crosslinking of vinyl imidazole with both hydrophilic and hydrophobic ionic liquid monomers. The resultant amphiphilic polymer membranes are porous and exhibit high absorption capacity of metal ions (including Hg²⁺ , Pb²⁺ , Cu²⁺ , Cd²⁺ , and Zn²⁺ ) in both high (1000 mg L^-1 ) and low (10 mg L^-1 ) concentration metal ion solutions. These metal ionic absorption membranes are easily regenerated in acid solution and can be reused without significant decreases of absorption capacity after many cycles. These PIL membranes may have potential applications as eco-friendly and safe heavy metal ion removal materials.