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

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.