Converting Metal–Organic Framework Particles from Hydrophilic to Hydrophobic by an Interfacial Assembling Route

Abstract

Here, we propose to modify the hydrophilicity of metal-organic framework (MOF) particles by an interfacial assembling route, which is based on the surface-active nature of MOF particles. It was found that hydrophilic UiO-66-NH particles can be converted to hydrophobic particles through an oil-water interfacial assembling route. The underlying mechanism for the conversion of UiO-66-NH was investigated by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. It was revealed that the close assembly of UiO-66-NH particles at the oil-water interface strengthens the coordination between organic ligands and metal ions, which results in a decrease in the proportion of hydrophilic groups on UiO-66-NH particle surfaces. Hydrophobic UiO-66-NH particles show improved adsorption capacity for dyes in organic solvents compared with pristine UiO-66-NH particles. It is expected that the interfacial assembling route can be applied to the synthesis of different kinds of MOF materials with tunable hydrophilicity or hydrophobicity required for diverse applications.

Colloid Syringeless Electrospinning toward Nonwoven Nanofiber Web Containing a Massive Amount of Inorganic Fillers

“…Figure a shows the SEM image of UiO‐66‐NH 2 MOF crystals synthesized using a previously reported method. [ 41 ] The diameter of the crystal is a few hundred nanometers, as shown in SEM images, but it is relatively difficult to maintain its colloidal state because of aggregations. The PAN‐MOF solutions are closer to the suspension state, but it is still possible to make a nonwoven nanofiber web using syringeless electrospinning with the desired concentration of MOF (Figure 6b,c).…”

“…Final product was dried at 80 °C oven to obtain Si particle as powder. The synthesis of UiO-66-NH 2 was conducted with the method described by Zhang et al [41] ZrCl 4 (0.240 g) and 2-aminoterephthalic acid (0.186 g) were dissolved in DMF (60 mL) and water was added (0.190 mL). The reaction was continued under vigorous stirring at 120 °C for 24 h. After the reaction, the mixture was washed several times with DMF and methanol and dried at 60 °C for 12 h to obtain yellowish powder as the final product.…”

ZnO@Bi5O7I Heterojunction Derived from ZIF-8@BiOI for Enhanced Photocatalytic Activity under Visible Light

“…ZIF-8, as a kind of well-known MOF, not only has the features of a porous and adjustable structure, but also overcomes the shortcomings of MOF materials such as poor hydrothermal stability and structural collapse [37]. ZIF-8 has been used as a sacrificial template to obtain a ZnO semiconductor with a large specific surface area, high purity, high crystallinity, and regular morphology after removing C, H, and N elements from the skeleton structure by high temperature heat treatment [38,39].…”

Polydimethyl siloxane/MIL-101 Composites for Enhanced Toluene Adsorption in the Presence of Humidity

“…Suggested surface modification strategies to increase MOF's hydrophobicity include ligand functionalization with hydrophobic moieties, 39,40 in-situ hydrophobization 41 and post-synthetic modification (PSM). 42,43 PSM is advantageous compared to the other methods which require high cost, involving complex synthesis procedures generating unknown final composite structure, as well as difficulty to scale up for large scale applications. 24,42 A simple PSM coating technique through vapor deposition of inexpensive polymers could be a promising approach to enhance MOF's pollutant selectivity and kinetics of VOCs adsorption from ambient air.…”

“…42,43 PSM is advantageous compared to the other methods which require high cost, involving complex synthesis procedures generating unknown final composite structure, as well as difficulty to scale up for large scale applications. 24,42 A simple PSM coating technique through vapor deposition of inexpensive polymers could be a promising approach to enhance MOF's pollutant selectivity and kinetics of VOCs adsorption from ambient air. 21 Polydimethylsiloxane (PDMS) is a hydrophobic, silicon-based polymer generally used to manufacture microfluidic structures, industrial sealants, and gaskets.…”