Fabrication of hierarchically porous NH2-MIL-53/wood-carbon hybrid membrane for highly effective and selective sequestration of Pb2+

Designing the desirable architecture for highly efficient sequestration of heavy metal ions is of paramount importance to ensure water safety. Herein, highly dense cuboid-like NH2-MIL-53 crystals have been in-situ immobilized on porous wood-carbon (WC) substrate (denoted as NH2-MIL-53/WC) based on a self-sacrificial template strategy. Benefiting from the perfect integration of unique 3D hierarchical pore structures, abundant binding sites, and specific sorption affinity of amino functional groups in NH2-MIL-53 toward Pb2+, the resulting NH2-MIL-53/WC hybrid membrane exhibits exceptional Pb2+ decontamination capability in terms of high uptake capacity, fast removal kinetics and superior selectivity in the presence of competing ions. Meanwhile, the macroscopic-sized monolithic shape is competent for facile separation, overcoming the inherent limitations of conventional nanosorbents. Furthermore, the as-fabricated monolithic membrane can be further assembled into a home-made filter system for continuous-flow wastewater purification, accompanied by an efficient treatment capacity of 2200 kg wastewater (spiked with 10 ppm Pb2+) per kg sorbent, while restricting the Pb2+ level in the effluent below the World Health Organization (WHO) limit (10 ppb). Such intriguing Pb2+ sequestration performance in both static and flowing states render the proposed NH2-MIL-53/WC hybrid membrane to hold huge prospects for the practical wastewater remediation.