Construction of self-healable and recyclable waterborne polyurethane-MOF membrane for adsorption of dye wastewater based on solvent etching deposition method

The treatment of dye wastewater by combining metal-organic framework (MOF) and polymer adsorbent membranes has attracted extensive attention. However, most of the polymer/MOF composite will encounter problems such as the poor compatibility, the holes of MOF are easily blocked by polymer chains, moreover, the study about the self-healable and recycle properties have never been done. To fill this gap, this research puts forward a novel solvent etching deposition method, combining waterborne polyurethane containing dynamic disulfide bonds (WPU-SS) with MOF (UiO-66-NH2) to prepare a self-healable and recyclable adsorption membrane (WPU-SS-MOF). The results show that WPU-SS-MOF membrane has excellent mechanical and self-healing properties, the tensile strength and elongation at break of WPU-SS-MOF membrane are 5.16 MPa and 1117.1%, respectively, and the self-healing efficiency can reach 96.1%. The adsorption experiments results show that WPUSS-MOF has excellent adsorption and recycling capacity for the anionic dyes of methyl orange (MO) and Congo red (CR), and the removal efficiency remained above 80% after 5 cycles. In summary, this is the first time to combine the function of adsorption of MOF with WPU-SS by a solvent etching deposition method, which provides vast application foreground for dye wastewater treatment.