Facile Synthesis of Quinolinecarboxylic Acid–Linked Covalent Organic Framework via One–Pot Reaction for Highly Efficient Removal of Water–Soluble Pollutants

To efficiently eliminate highly polar organic pollutants from water has always been a difficult issue, especially in the case of ultralow concentrations. Herein, we present the facile synthesis of quinolinecarboxylic acid-linked COF (QCA–COF) via the Doebner multicomponent reaction, possessing multifunction, high specific surface area, robust physicochemical stability, and excellent crystallinity. The marked feature lies in the quinolinyl and carboxyl functions incorporated simultaneously to QCA–COF in one step. The major cis–orientation of carboxyl arms in QCA–COF was speculated by powder X–ray diffraction and total energy analysis. QCA–COF demonstrates excellent adsorption capacity for water–soluble organic pollutants such as rhodamine B (255.7 mg/g), methylene blue (306.1 mg/g), gentamycin (338.1 mg/g), and 2,4–dichlorophenoxyacetic acid (294.1 mg/g) in water. The kinetic adsorptions fit the pseudo–second order model and their adsorption isotherms are Langmuir model. Remarkably, QCA–COF can capture the above four water–soluble organic pollutants from real water samples at ppb level with higher than 95% removal efficiencies and excellent recycling performance.