Guo Dongsheng research group of Nankai University: highly sensitive, specific detection and highly effective adsorption of perfluorinated pollutants

Water pollution has become one of the most urgent environmental problems in the world Perfluoroalkyl compounds, such as perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are widely used in fluoropolymer, foam extinguishing agents and other fields of production Because of its high toxicity, persistence, bioaccumulation, long-distance migration and other properties, it has a serious harm to human health and environment At present, the detection methods of PFOS and PFOA mostly need precise instruments and complex operations, while the low-cost and simple spectral rules are limited by low sensitivity Because of the high bond energy of C-F bond, the degradation of PFOS and PFOA is very difficult, and new toxic by-products will be produced Adsorption is the most effective way to purify polluted water However, the classical adsorbents such as activated carbon and resin lack the specificity for PFOS and PFOA At present, there are few researches on the specific adsorbents of PFOS and PFOA, and there is no real-time detection and efficient adsorption in the same system Therefore, it is of great significance to design and synthesize artificial receptors with selective and strong binding for PFOS and PFOA, and to achieve high sensitivity detection and specific adsorption at the same time Recently, according to the structural characteristics of PFOS and PFOA, Professor Guo Dongsheng's research group of Nankai University designed guanidine modified calixarene as the main body for specific combination of PFOS and PFOA Based on this, a high sensitive supramolecular sensing and high efficient adsorption system was constructed to detect and adsorb PFOS and PFOA in wastewater Firstly, the bond behavior of guanidine calixarenes with PFOS and PFOA was investigated in detail The experimental results show that the calixarenes are strongly bonded to PFOS and PFOA by electrostatic, hydrogen bonding, van der Waals and hydrophobic interaction, and the binding constant can reach the order of nm Guanidine calixarenes are highly sensitive, specific and highly adsorbed perfluorinated pollutants (source: nature Communications) With the aid of indicator replacement detection method, fluorescein is used as fluorescence indicator The authors have realized the fluorescence quantitative detection of PFOS and PFOA in buffer solution, tap water and lake water The detection limit can be as low as 21.4 nm (11.3 μ g L-1), indicating that the detection method can be directly applied to the detection of heavily polluted water sources such as airports, industrial parks and military bases The detection of PFOS and PFOA in slightly polluted water can be realized by solid-phase extraction and concentration and then detection In addition, the standard curves of PFOS and PFOA are established by using mobile app The visual detection of PFOS and PFOA can be realized without professional spectrophotometer Furthermore, the guanidine calixarenes loaded with Fe3O4 nanoparticles were constructed, which can effectively adsorb and separate PFOS and PFOA in water through simple magnetic adsorption and membrane treatment This supramolecular strategy based on molecular recognition and assembly of calixarenes has a broad application prospect in the detection and adsorption separation of perfluorinated pollutants in wastewater This research result has been published in nature communications (DOI: 10.1038 / s41467-019-13775-1) recently The first author of this paper is Zheng Zhe, a doctoral candidate of Nankai University, and the corresponding author is Professor Guo Dongsheng.