A hydrophobic–superoleophilic 2D Zr-based alkyne-rich metal–organic framework for oil/water separation and solar-assisted oil evaporation

Abstract

A 2D layered Zr-based metal–organic framework (MOF), ZrL1, was assembled from Zr(IV) ions and backfolded alkyne-rich dicarboxylate linker (L1²⁻). Structurally robust and chemically stable ZrL1 was dip-coated on polyurethane (PU) to give a composite ZrL1@PU, which exhibited significantly enhanced oil/water separation performance (maximum absorption capacity: 66.19 g g⁻¹, separation efficiency: 99.3%, selectivity: water totally excluded, and permeability: 5340 L m⁻² h⁻¹) when compared with pristine PU. More importantly, ZrL1@PU maintained steady performance and framework stability even upon 20 cycles of operation. Given that ZrL1@PU is photothermally active, it was taken for solar-driven evaporation of the oil harvested during oil/water separation, and the evaporation efficiency of ZrL1@PU (complete evaporation within 25–40 minutes) outperforms that of pristine PU (30 wt% of the selected oil still remained within the same illumination period). This study represents an illustrative example giving insights into the rational design of hydrophobic/superoleophilic framework for fabricating efficient durable self-cleaning oil/water separator.