Facile preparation of porous organic copolymer based on triptycene and crown ether for efficient organic dye adsorption

There has been great interest in the use of porous polymers to remove organic dyes because of their adjustable surface area and task-specific functionality. We chose a triptycene-based porous polymer to ensure high porosity, and introduced crown ether into the sketch of the copolymer to significantly enhance the affinity for the organic dye molecules. Novel porous organic copolymers of triptycene and crown-ether-15 (POP-TCE-15) were obtained by a simple Friedel-Crafts reaction, and were highly effective in removing organic dyes from aqueous solution. POP-TCE-15 exhibited the best performance, with a maximum adsorption capacity of methylene blue, rhodamine B, and methyl orange of 787.4 mg g-1, 421.9 mg g-1, and 64.8 mg g-1, respectively, which is better than most reported adsorbents. Their adsorption rates and adsorption isotherms were well fitted with pseudo-second-order kinetic models and the Langmuir model. More importantly, POP-TCE-15 can be effectively regenerated and recycled at least 5 times without any loss of adsorption capacity. With a hierarchical porous structure, high surface area, high hydrophobicity, and excellent adsorption capacity for dyes, the POP-TCE polymers could be ideal adsorbents for water purification and treatment.