Porous polymer gels (PPGs) are characterized by inherent porosity, a predictable structure, and tunable functionality, which makes them promising for the heavy metal ion trap in environmental remediation. However, their real-world application is obstructed by the balance between performance and economy in material preparation. Development of an efficient and cost-effective approach to produce PPGs with task-specific functionality remains a significant challenge. Here, a two-step strategy to fabricate amine-enriched PPGs, NUT-21-TETA (NUT means Nanjing Tech University, TETA indicates triethylenetetramine), is reported for the first time. The NUT-21-TETA was synthesized through a simple nucleophilic substitution using two readily available and low-cost monomers, mesitylene and α, α′-dichloro-p-xylene, followed by the successful post-synthetic amine functionalization. The obtained NUT-21-TETA demonstrates an extremely high Pb2+ capacity from aqueous solution. The maximum Pb2+ capacity, qm, assessed by the Langmuir model was as high as 1211 mg/g, which is much higher than most benchmark adsorbents including ZIF-8 (1120 mg/g), FGO (842 mg/g), 732-CR resin (397 mg/g), Zeolite 13X (541 mg/g), and AC (58 mg/g). The NUT-21-TETA can be regenerated easily and recycled five times without a noticeable decrease of adsorption capacity. The excellent Pb2+ uptake and perfect reusability, in combination with a low synthesis cost, gives the NUT-21-TETA a strong potential for heavy metal ion removal.

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The tetracycline hydrochloride (TCH) removal from wastewater is important for the environment and human health yet challenging. Herein, the Eu-based MOF, Eu(BTC) (BTC represents 1,3,5-trimesic acid) was prepared by an efficient and environmental-friendly strategy, and then was used for the TCH capture for the first time. The Eu(BTC) was characterized by different methods such as X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy. The TCH uptake of Eu(BTC) was investigated systematically. The influences of experiment conditions such as solution pH value, adsorption time and initial concentration on TCH capacity of Eu(BTC) were also studied. The Eu(BTC) obtained exhibited remarkable TCH uptake (qm was up to 397.65 mg/g), which was much higher than those of most materials such as UiO-66/PDA/BC (184.30 mg/g), PDA-NFsM (161.30 mg/g) and many carbon-based materials reported till now. Besides, the TCH adsorption behavior on Eu(BTC) was explored by Freundlich and Langmuir equations, and the adsorption mechanism was further analyzed. The experimental results suggested that the TCH adsorption mechanism of Eu(BTC) included the π–π interaction, electrostatic interaction and coordinate bonds. The excellent TCH adsorption performance and the efficient fabrication strategy make the Eu(BTC) prepared promising in TCH removal.