MOF/hydrogel composite-based adsorbents for water treatment: A review

Metal-organic frameworks (MOFs) materials have been considered as one of the most promising adsorbents for water treatment via the adsorption technique, due to their excellent skeleton structure, abundant porosity, and extremely high internal surface area. However, MOFs are normally in form of powder or crystal, which greatly limits their application because of the intrinsic fragility, poor processability and recoverability. Therefore, MOFs are commonly introduced into hydrogel matrixes, leading to a series of MOF/hydrogel composites with advanced adsorption properties and flexibility. Herein, we focus on the recent development of strategies used for the combing of MOFs and hydrogels, and the pros/cons of each method are discussed. Furthermore, performance of MOF/hydrogel based adsorbents for the removal of metal ions, organic dyes and drug residue molecules are reviewed. To explore their structure-performance relationship, microstructure, adsorption capacity and recyclability of MOF/hydrogels synthesized via different routes are presented. Finally, challenges and outlooks regarding to the green synthesis, stability and computational design of MOF/hydrogel composites are briefly discussed.