For the first time, a novel amidinothiourea-linked covalent organic framework (COF) (TpAt) has been successfully synthesized by the condensation between 1,3,5-triformylphloroglucinol and amidinothiourea via vacuum solvothermal reaction, and was further utilized for the adsorption of metal ions from aqueous solution. The effects of initial concentration, pH and contact time on the adsorption process were investigated. As a result, the TpAt COF showed maximum binding capacities as high as 95.44, 100.76 and 99.08 mg g^–1 for Cr(III), Cd(II) and Cu(II) within 180 min at the initial concentration of 100 mg L^–1, respectively. The isotherms of metal ions onto TpAt could be described by the Freundlich isotherm equation, and the adsorption kinetics followed the pseudo-second-order model. The TpAt could be reused for more than five adsorption–elution cycles, whilst basically maintaining its original adsorption performance and the structural integrity of the COF layers. The robust adsorption efficiency can be attributed to the coordination between metal ions and N, O and S atoms in the TpAt framework. The TpAt COF represents an ideal candidate for the removal of heavy metal ions in environmental pollution treatment. © 2021 Society of Industrial Chemistry.

中文翻译：

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用于吸附重金属离子的脒基硫脲连接的共价有机骨架

1,3,5-三甲酰间苯三酚与脒基硫脲通过真空溶剂热反应首次成功合成了一种新型脒基硫脲连接的共价有机骨架（COF）（TpAt），并进一步用于金属的吸附水溶液中的离子。考察了初始浓度、pH 值和接触时间对吸附过程的影响。因此，TpAt COF在 100 mg L 的初始浓度下，在 180 分钟内对 Cr(III)、Cd(II) 和 Cu(II)显示出高达 95.44、100.76 和 99.08 mg g ^{-1 的}最大结合容量^{– 1}， 分别。金属离子在 TpAt 上的等温线可用 Freundlich 等温方程描述，吸附动力学遵循拟二级模型。TpAt 可以重复使用超过五个吸附-洗脱循环，同时基本保持其原始吸附性能和 COF 层的结构完整性。强大的吸附效率可归因于金属离子与 TpAt 框架中的 N、O 和 S 原子之间的配位。TpAt COF 是去除环境污染处理中重金属离子的理想选择。© 2021 工业化学学会。