Owing to the severe environmental and ecological issues arising from oil spills and toxic chemical leakage, the separation of oil from water presents a worldwide challenge to save the endangered environment. A versatile absorbent which can deal with different types of oil contaminants is in high demanded for this issue. In this work, we obtain an ultralight, fire-resistant, and compressible foam (UFC foam) by pyrolysis and post hydrophobic-modified treatment using commercially available poly(melamine formaldehyde) foams as precursors. The present UFC foam not only effectively separates oils from water as expected, but also possesses a very high absorption capacity for the removal of oils from water up to 158 times its own weight. More importantly, due to its fire resistance and compressibility, distillation, combustion and squeezing, or a combination of these can be applied for recycling the foams depending on the type of pollutants, making them versatile and comprehensive absorbents to satisfy various practical separation requirements.

We report a facile method to synthesize Fe3O4@polydopamine (PDA)-Ag core–shell microspheres. Ag nanoparticles (NPs) are deposited on PDA surfaces via in situ reduction by mussel-inspired PDA layers. High catalytic activity and fast adsorption of a model dye methylene blue (MB) at different pH values are achieved mainly due to the presence of monodisperse Ag NPs and electrostatic interactions between PDA and MB. The as-prepared Fe3O4@PDA-Ag microspheres also show high cyclic stability (>27 cycles), good acid stability, and fast regeneration ability, which can be achieved efficiently within several minutes by using NaBH4 as the desorption agent, showing great potentials in a wide range of applications.Keywords: cyclic stability; dye removal; fast adsorption; Fe3O4@PDA-Ag microspheres; in situ reduction; polydopamine; regeneration ability; water treatment;

A novel dissocyanate-modified lignin xerogel is facilely prepared using renewable lignin as precursors via a sol–gel process and ambient pressure drying method. The xerogel possesses high performance in self-cleaning and superhydrophobicity with no need for further hydrophobic modification. Furthermore, the xerogel obtained can find potential applications in absorbents, coatings, and scaffolds.Keywords: Lignin; One-pot reaction; Self-cleaning; Superhydrophobicity; Xerogels;

Understanding of H- and J-aggregation behaviors in fluorene-based polymers is significant both for determining the origin of various red-shifted emissions occurring in blue-emitting polyfluorenes and for developing polyfluorene-based device performance. In this contribution, we demonstrate a new theory of the H- and J-aggregation of polyfluorenes and oligofluorenes, and understand the influence of chromosphere aggregation on their photoluminescent properties. H- and J-aggregates are induced by a continuous increasing concentration of the oligofluorene or polyfluorene solution. A relaxed molecular configuration is simulated to illustrate the spatial arrangement of the bonding of fluorenes. It is indicated that the relaxed state adopts a 21 helical backbone conformation with a torsion angle of 18° between two connected repeat units. This configuration makes the formation of H- and J-aggregates through the strong π–π interaction between the backbone rings. A critical aggregation concentration is observed to form H- and J-aggregates for both polyfluorenes and oligofluorenes. These aggregates show large spectral shifts and distinct shape changes in photoluminescent excitation (PLE) and emission (PL) spectroscopy. Compared with “isolated” chromophores, H-aggregates induce absorption spectral blue-shift and fluorescence spectral red-shift but largely reduce fluorescence efficiency. “Isolated” chromophores not only refer to “isolated molecules” but also include those associated molecules if their conjugated backbones are not compact enough to exhibit perturbed absorption and emission. J-aggregates induce absorption spectral red-shift and fluorescence spectral red-shift but largely enhance fluorescence efficiency. The PLE and PL spectra also show that J-aggregates dominate in concentrated solutions. Different from the excimers, the H- and J-aggregate formation changes the ground-state absorption of fluorene-based chromophores. H- and J-aggregates show changeable absorption and emission derived from various interchain interactions, unlike the β phase, which has relatively fixed absorption and emission derived from an intrachain interaction.

Owing to the severe environmental and ecological issues arising from oil spills and toxic chemical leakage, the separation of oil from water presents a worldwide challenge to save the endangered environment. A versatile absorbent which can deal with different types of oil contaminants is in high demanded for this issue. In this work, we obtain an ultralight, fire-resistant, and compressible foam (UFC foam) by pyrolysis and post hydrophobic-modified treatment using commercially available poly(melamine formaldehyde) foams as precursors. The present UFC foam not only effectively separates oils from water as expected, but also possesses a very high absorption capacity for the removal of oils from water up to 158 times its own weight. More importantly, due to its fire resistance and compressibility, distillation, combustion and squeezing, or a combination of these can be applied for recycling the foams depending on the type of pollutants, making them versatile and comprehensive absorbents to satisfy various practical separation requirements.