Facile fabrication of robust MOF membranes on cloth via a CMC macromolecule bridge for highly efficient Pb(II) removal

Developing highly uniform and compact metal-organic frameworks (MOFs) membranes grown on flexible substrate such as cloth for highly efficient heavy metal removal is an appealing yet challenging task. Herein, we demonstrate a facile route to rapidly in situ synthesize Zn/Co-ZIF crystals onto cloth to form robust and compact MOF membranes at room temperature. Carboxymethylcellulose sodium (CMC) is introduced to act as a macromolecule bridge to promote the chemical surface attachment of Zn/Co-Zeolite Imidazolate Frameworks (Zn/Co-ZIF) crystals while simultaneously impeding solution-phase crystal agglomeration. SEM, XRD and FT-IR spectra were used to characterize the CMC-MOF/Cloth composite membranes. Benefiting from the intrinsic properties of Zn/Co-ZIF, the CMC-MOF/Cloth shows remarkable selectivity and excellent adsorption capacity (862.44 mg g−1) toward Pb(II). Detailed adsorption behaviour and mechanism are revealed by batch sorption runs with Pb(II) and a series of structural characterizations, respectively. In addition, the CMC-MOF/Cloth composite membranes can rapidly decontaminate the concentration of Pb(II) with good removal efficiency using a filtration apparatus, as well as exhibit splendid reusability for multiple regeneration cycles, which demonstrate the CMC-MOF/Cloth composite membranes, being as an efficient, low-cost, easy-obtained, and environmental-friendly MOF-based membranes, possesses great potential for the removal of Pb(II) in water purification.