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/Zr-MOFs/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/Zr-MOFs/PU foam still exhibits high stability and reusability after five cycles.

Asymmetric Sc-PLA Membrane with Multi-scale Microstructures: Wettability, Antifouling, and Oil-Water Separation.

In this work, an eco-friendly superhydrophobic stereo-complex polylactic acid (Sc-PLA) membrane was fabricated by a facile non-solvent-induced phase separation (NIPS) method, followed by peeling off its skin layer. By adjusting the thickness and roughness, membranes with various multi-scale microstructures could be obtained due to the formation of stereo-complex crystals during the process of phase separation. The Sc-PLA membranes display a hydrophobic wetting property. Interestingly, when the skin layer of the membrane with a 600 µm thickness was peeled off, the water contact angle on the surface of the membrane significantly improved from 142 to 152°, and the membrane displayed superhydrophobic wetting properties, which may be owing to the improvement of roughness for the surface by enlarging the exposure opportunity of finger holes and microstructures. In addition, the Sc-PLA membrane with superhydrophobicity shows excellent antifouling performance and large oil absorption capacity. Predictably, the Sc-PLA membranes may have potential applications in antifouling and oil-water separation.