Adsorption of volatile organic compounds by chemically modified hPEI (expanded hPEI)-based supramolecular organogel

The adsorption approach for treating volatile organic compounds (VOCs) offers advantages including high efficiency, safety, absence of secondary pollution, and strong adaptability. Today's development is still hampered by factors such as limited adsorption capacity and the high energy consumption associated with separation processes. Here, terpyridine and tetraphenylene groups are chemically grafted to a polyethyleneimine backbone, and the resulting hPEI@LysTPY@TPE-COOH polymer could gel in a series of organic solvents triggered by ultrasound stimuli. The organogel in cyclohexanol exhibits a green emission, which is distinct from that in other solvents. This unique property facilitates the visual recognition. of cyclohexanol among the tested solvents. Additionally, The organogel was capable of efficiently and continuously adsorbing and liquefying volatile organic compounds (VOCs) at room temperature over several days, operating through a biomimetic osmotic pressure-like adsorption process. The organogel exhibits a remarkable capacity for the selective absorption of acetone (11.7 g/g), carbon tetrachloride (2.5 g/g), and ethyl acetate (3.2 g/g) gas via multiple supramolecular interactions. This process results in the formation of two distinct phases: a solvent-poor phase in a gel state and a solvent-rich phase in a solution state (97 wt%), which could be effortlessly separated. The adsorbents could be regenerated after solution exchange. Finally, the adsorption of carbon tetrachloride is also accompanied by fluorescence quenching, endowing visual detection of the process. The work demonstrates a widely used approach for prepare novel supramolecular material with superior adsorption and separation performance.