Fabrication of 2D nanosheet sorbents through metastable emulsion droplets and subsequent two-step grafting polymerization for efficient blood lead removal in vitro

Hemoperfusion is a powerful and yet simple method for lead poisoning treatment, but creation of safe and effective sorbents with excellent selectivity remains a real challenge. To address this, we here construct 2D nanosheet sorbents (BM-SH) through metastable emulsion droplets and subsequent two-step grafting polymerization for efficient blood lead removal in vitro. Metastable emulsion droplets endow typical nanosized sheet-like structure (thickness of 30 nm) and relatively round shape. The consecutive two grafting processes using hydroxyethyl methacrylate (HEMA) and L-cysteine monomer (D-SH) provide BM-SH with a high density of accessible binding sites towards lead ions (Pb2+). A high adsorption capacity of 390.5 mg g-1 and quick capture 97.35 % of Pb2+ within initial 10 min are obtained, surpassing most of the reported sorbents for lead removal. Besides, adsorption distribution coefficient (Kd) of BM-SH among four coexisting metal ions achieved 7792 mL g-1, showing outstanding selectivity toward Pb2+. Importantly, a possible adsorption mechanism is recognized as coordination with carboxyl, sulfydryl and imino groups from L-cysteine, and mercapto ligand as the key chelating agent may be the reason for high Pb2+ affinity. And what's more, BM-SH displays good hemocompatibility and high efficiency of blood lead removal rate (above 86 % in vitro).