Reusable Cavitand‐Based Electrospun Membranes for the Removal of Polycyclic Aromatic Hydrocarbons from Water

Abstract

organic compounds made of two or more aromatic rings, fused together in linear, angular, or cluster arrangements. They can be also referred as low-molecular weight PAHs (two or three rings) and high-molecular weight PAHs (four or more rings). [3] These ubiquitous compounds can be generated from both anthropogenic activities, such as industrial, residential, and vehicular emissions, and natural pheno mena, i.e., open burning, volcanic activities, and spills from coal deposits. [2,3,[5][6][7] The occurrence of PAHs has been assessed worldwide in different aquatic systems including influents and effluents from wastewater treatment plants, groundwater, surfaceand sea-water. [3] Currently, over 400 PAHs and derivatives have been identified and classified, but most regulations, analyses, and data are focused on only 14 to 20 PAH compounds. [2,3,7] PAHs are well-known toxic, mutagenic, either carcinogenic or suspected carcinogenic compounds, accumulating in human and animal tissues. [2,3] These compounds are characterized by high hydrophobicity and good lipid solubility due to their aromatic and delocalized structure: when their molecular weight increases, their aqueous solubility diminishes, whereas resistance to oxidation and reduction rises. [2][3][4] PAHs absorption and bioaccumulation in several tissues, as well as their ubiquitous occurrence in the environment, pushed US EPA (United States Environmental Protection Agency) and EEA (European Environment Agency) to identify 24 PAH compounds as priority contaminants, thus introducing strict regulations for their monitoring. [8][9][10][11] The 16 PAHs considered as priority pollutants by US EPA are: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd] pyrene, dibenz[a,h]anthracene, and benzo[ghi]perylene (Chart S1, Supporting Information). The European Union has set the maximum limit of 0.1 µg L −1 as sum of benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, and indeno [1,2,3-cd] pyrene in water for human consumption, with a particular attention to benzo[a]pyrene limited to 0.01 µg L −1 . [12] The removal of PAHs represents one of the current challenges in environmental chemistry. Methods are based on biodegradation, chemical, and physical removal processes, often combined in order to obtain the highest degree of PAHs removal. [2][3][4]6,7,13] Despite biological treatment methods have been proposed in municipal wastewaterThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202104946.

Endocrine Disrupting Chemicals’ Effects in Children: What We Know and What We Need to Learn?

“…Samples treatment plays an important role to achieve reliable results, especially when EDCs’ determinations at low levels are performed in complex matrices, such as biological fluids. The use of sorbent materials able to guarantee a selective EDCs’ extraction is demanded: boosting detection selectivity requires that specific binding interactions dominate over the non-specific ones [ 63 , 64 , 65 ]. To accomplish this task, molecular receptors must to be devised according to their targets and they need to be structured in architectures which retain the designed molecular recognition functionalities in real-world working conditions.…”

Structural characterization of the supramolecular complex between a tetraquinoxaline-based cavitand and benzonitrile

“…With their ability to close and open upon external stimulation, QxCavs can be used to grab and release molecules, acting as molecular grippers (Milic & Diederich, 2019). By incorporating these gripper-like cavitands in polymers, the pH-driven conformational switch is maintained (Brighenti et al, 2018) and can be used to regenerate QxCav-based membranes for the removal of polycyclic aromatic hydrocarbons from water under relatively mild conditions (Amorini et al, 2022). By covalently embedding QxCavs in polymeric matrices, indeed, the vase-kite switching can be controlled by mechanical stimulation (Torelli et al, 2020), leading to the unprecedented observation of an auxetic behaviour in a polymer of intrinsic microporosity (PIMs; Portone et al, 2023).…”

Supramolecular Materials as Solid-Phase Microextraction Coatings in Environmental Analysis

“…As in the case of CDs and calixarenes, the upper rim of the receptors can be functionalized to obtain deeper cavities, tuned polarities, or different complexation capabilities, whereas the substituents at the lower rim are mostly used to tune the macrocycle solubility or to improve the anchoring on a substrate. Very recently, our research group developed and tested a novel cavitand characterized by four benzoquinoxaline walls at the upper rim (BenzoQxCav) as SPME coatings for the extraction of PAHs from water samples ( Figure 11 c) [ 150 , 151 ]. Compared to the tetraquinoxaline cavitand, the new receptor was characterized by a 2.5 Å deeper hydrophobic cavity, able to host large guests such as PAHs.…”