Wei Li,Yue-Lei Hao,Wei-Liang Jin,Jing-Qi Liu,An-Na Tang,Li-Na Zhu,Hong-Xin Jiang,De-Ming Kong
The assessment and treatment of heavy metal pollution are eternal subjects of environmental protection. Facile on-site assessment of heavy metal pollution and efficient, rapid removal of pollutes are still challenging. Covalent organic frameworks (COFs) hold great promise as absorbents for heavy metal pollution treatment. To overcome the application limits of COF powders, a COF-based monolithic composite is prepared by direct in-situ growth of an N/O-rich COF on the surface of a melamine foam (MF). The resultant MF@COF inherits the macro-porous channels of MF, the good crystallinity of COF, and integrates the attractive features of monolithic materials such as ease of operation, facile and highly efficient recovery, and good reusability . The abundant N/O groups endow MF@COF with powerful capture capability towards various heavy metal ions . Its maximum adsorption capacity for Cd 2+ is 278.45 mg/g, and the adsorption equilibrium can be reached within 1–3 s. The adsorption kinetic of Cd 2+ by MF@COF follows the pseudo-second-order kinetic model , and the adsorption isotherm conforms to Freundlich model. Rapid adsorption, together with the easy-to-operate feature of monolithic material, make the ultrafast water purification possible. Meanwhile, MF@COF works well for the highly efficient enrichment of Cd 2+ to realize the naked-eye detection of Cd 2+ pollution at low levels, thus may be developed as an important tool for both on-site assessment and rapid treatment of heavy metal pollution.
Dicofol is an organochlorine pesticide, which is widely used in fruits, tea and other crops, and is moderately toxic to humans. Therefore, the monitoring of organochlorine pesticide-dicofol is critical for food safety. In this work, a fluorometric chemosensor based on mercaptoethanol and boron dipyrromethene (BODIPY) was first constructed to detect the dicofol. The chemosensor displayed turn-off fluorescence behavior upon dicofol with a detection limit of 200 ppb. The nucleophilicity of the glutathione and other biological thiols was studied to evaluate the reactivity of thiols with dicofol. In practical applications, an obvious color difference was observed on a paper based microfluidic device modified by phenyltriethoxysilane (PTES). We designed an integrated device for pretreatment and paper-based detection, and successfully used for the detection of dicofol in tea. The applicability was demonstrated by detection of dicofol in real tea samples with good recovery ranging from 86% to 109%. The apparatus was convenient and could be used for on-site evaluation of dicofol.
危险品化学品经营许可证（带存储）