Zr-MOFs loaded on polyurethane foam by polydopamine for enhanced dye adsorption

Zirconium-based metal-organic frameworks (Zr-MOFs) have attracted widespread attention due to their high specific surface area, high porosity, abundant metal active sites and excellent hydrothermal stability. However, Zr-MOFs materials are mostly powdery in nature and thus difficult to separate from aqueous media, which limits their application in wastewater treatment. In this study, PDA/Zr-MOFs/PU foam was constructed by growing Zr-MOFs nanoparticles on a dopamine-modified polyurethane foam substrate by in-situ hydrothermal synthesis as an adsorbent for removing dyes from wastewater. The results demonstrated that the polydopamine coating improves the dispersion of the Zr-MOFs nanoparticles on the substrate and enhances the interaction between the Zr-MOFs nanoparticles and the PU foam substrate. As a result, compared with Zr-MOFs/PU foam, the prepared PDA/ZrMOFs/PU foam exhibits higher adsorption capacity for crystal violet (CV) (63.38 mg/g) and rhodamine B (RB) (67.73 mg/g), with maximum adsorption efficiencies of CV and RB of 98.4% (pH=11) and 93.5% (pH=7), respectively, at a concentration of 10 mg/L. The PDA/Zr-MOFs/PU foam can simultaneously remove CV and RB from the mixed solution. Moreover, the PDA/ZrMOFs/PU foam still exhibits high stability and reusability after five cycles. (C) 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

Automated summary

In this study, PDA/Zr-MOFs/PU foam was synthesized for dye removal from wastewater. The polydopamine coating improved the dispersion of Zr-MOFs nanoparticles and enhanced their interaction with the PU foam substrate. The prepared foam showed higher adsorption capacity and efficiency for crystal violet and rhodamine B, and maintained stability and reusability after multiple cycles.