One-pot synthesis of fluorine functionalized Zr-MOFs and their in situ growth on sponge for oil absorption

Abstract

The treatment of oil spill and the separation of oil-water mixture have been widely concerned in recent years. In this work, a one-pot synthesis strategy is developed to prepare fluorine functionalized zirconium-based metal organic framework (Zr-MOFs) (denoted as UiO-66-1F) by using 4-fluorobenzoic acid as modulator and modifier and p-phthalic acid (PTA) as ligand. 4-fluorobenzoic acid can participate in the formation of frameworks structure and cause structural defects, causing larger surface area and hierarchically porous structure. The hydrophobicity of UiO-66-1F increases with increasing of the ratio of 4-fluorobenzoic acid to zirconium chloride and when the ratio is 10, the synthesized UiO-66-1F(10) shows high hydrophobicity with a water contact angle (WCA) of 122° while the WCA of original UiO-66 is only 21°. UiO-66-1F(10) also has good chemical stability over a wide pH range (pH 1∼11) and good hydrothermal stability. In addition, a superhydrophobic sponge (UiO-66-1F(10)@PDA@sponge) with a WCA of 150° was prepared via in situ growth of UiO-66-1F(10) on a polydopamine modified sponge (PDA@sponge). The resulting composite shows high absorption capacities for various oils and organic solvents ranging from 50.5 g/g (n-hexane)– 107.8 g/g (dichloromethane) and good recyclability.