Aryl‐aryl linked two‐dimensional covalent organic frameworks/cellulose composite monolith with hierarchical structure for aqueous dyes adsorption

Abstract Aryl‐aryl linked two‐dimensional covalent organic frameworks (2D‐COFs) were synthesized by interfacial trimerization of 4,4′‐diacetylbiphenyl. The 2D‐COFs presented rigid skeleton structure, regular porosity and micron‐scale layered nanosheet structure, which can be easily exfoliated by sonication without destroying the micron size. The integration of 2D‐COFs and cellulose matrix via non‐solvent‐induced phase separation has facilely generated 2D‐COFs/cellulose composite monolith with hierarchical structure bearing nano/micro scale pores and 2D/3D dimensions. The composite monolith material has been successfully applied to dye adsorption using methylene blue (MB) and rhodamine B (RhB) as model adsorbates under aqueous conditions. At an initial dye concentration of 200 mg L −1 and neutral pH conditions, excellent adsorption capacities were presented (91.5 mg g −1 for MB, 67.3 mg g −1 for RhB), with satisfactory recyclability and good compatibility to different dye concentrations and pH environment. We anticipate the techniques will broaden the fabrication of COFs and related composite materials, and enable promising practical applications in porous materials and waste water treatment.