Matchstick-like metal-organic framework-based superwetting materials for efficient multiphase liquid separation via filtration or adsorption

Abstract

Superwetting materials with opposite affinities to water and oil have been widely applied for separating oil-water system. However, separation of organic liquid mixtures remains great challenge owing to its lower surface tension differences. Herein, solvent-induced separation strategy based on the polarity reaction between the liquids and material is proposed to build superwetting surfaces in polar-apolar liquids system. The copper mesh/foam (CuM/CuF) were firstly etched via an alkaline catalyzed oxidation method to form microneedles, and then coordinated with the organic ligands to generate Metal-organic framework (MOF) nanorods on the microneedles that defined as CuM@MOF/CuF@MOF, and further modified with alkanethiol, finally obtaining the CuM@MOF@Thiol or CuF@MOF@Thiol. The synergetic effect of the structural morphology and chemical compositions realized the controllable regulation of their wettability and adsorption property. The CuM@MOF as filtration membranes that performed superlyophobicity to apolar liquid under polar liquids was used to separate the heavy polar liquid-light apolar liquid mixtures. Besides, the CuM@MOF@Thiol with superlyophbicitiy to polar liquids under apolar liquids could be applied for the filtrating separation of light polar liquid-heavy apolar liquid mixtures. Moreover, the CuF@MOF with superlyophilic to polar liquids under apolar liquids and CuF@MOF@Thiol with superlyophilic to apolar liquids under polar liquids could be applied for on-demand adsorbing separation of both the heavy polar-light apolar and light poalr-heavy apolar mixtures. Thus, the superwetting MOF-based mesh/foam can selectively absorb one phase while repel the immiscible phase with opposite polarity, realizing high-efficiency separation of organic liquids via selective filtrating or absorbing.