Gas–Liquid Reactions to Synthesize Positively Charged Fe₃O₄ Nanoparticles on Polyurethane Sponge for Stable and Recyclable Adsorbents for the Removal of Phosphate from Water

The application of most current phosphate adsorbents is limited by their high cost, low removal capacity, difficulty of recovery, and short lifetime. In this study, we developed a gas–liquid reaction assisted by a coordination method to prepare highly positively charged ferroferric oxide (Fe3O4) nanoparticles loaded on polyurethane sponge. It was found that the gas–liquid reaction drastically decreases the size and increases the loading capacity of Fe3O4 nanoparticles as compared with the conventional liquid method. Further, the use of trimethylamine vapor induced the coordination of Fe3+, facilitated the formation of free Cl ions, and inhibited the hydrolysis of Fe–Cl bonds, thus greatly decreasing the amount of hydroxyl groups and increasing the surface positive charge on Fe3O4 nanoparticles. As a result, the Fe3O4 nanoparticles in this study have a saturated PO43– adsorption capacity of 229.8 mg·g–1, which was appreciably higher than that of conventional Fe3O4 adsorbents (57.8 mg·g–1). Our study further revealed that the introduction of a thin layer of polyurethane coating on the surface of Fe3O4 nanoparticle-composited adsorbents could drastically improve their stability while preserving the adsorption capacity under the impact of water (500 rpm stirring for 72 h). The composited adsorbents also preserve the adsorption capacity after recycling three times. Finally, the adsorption experiment on real river wastewater indicated that the composited adsorbents enable the decrease of phosphate concentration from 0.6 to 0.02 ppm, reflecting the application potential for relieving phosphate pollution in neutral waters

Facile Template-Free Fabrication of Aluminum-Organophosphorus Hybrid Nanorods: Formation Mechanism and Enhanced Luminescence Property

Recently, much effort has been directed toward fabrication of metal-organophosphorus hybrids with microporous, fibered, layered, and open structures to obtain desired mechanical, optical, electric, and catalytic properties. In this work, aluminum–phosphorus hybrid nanorods (<b>APHNRs</b>) with regular morphology were prepared by a template-free hydrothermal reaction of aluminum hydroxide with diphenylphosphinic acid (DPPA). Structure characterization of <b>APHNRs</b> by Fourier transform infrared spectroscopy, laser Raman spectroscopy, and X-ray diffraction demonstrate a structure with aluminophosphate main chains and phenyl pendant groups, which enable self-assembly into nanorods. The reaction conditions and the structures of phosphinic acids appear to have a significant impact on the morphology and size of nanorods. Moreover, the evolution of morphology and structure assembly during the forming process of <b>APHNRs</b>, as monitored by SEM and XRD, reveal a decomposition-assembly propagation process where the driving force of assembly is attributed to π–π stacking interactions between phenyl pendant groups. <b>APHNRs</b> show a significant increase in light emission relative to pure DPPA due to their compact structure resulting from the π–π stacking interaction. Detailed investigation revealed that photoluminescence was remarkably amplified by enhancing the compactness of <b>APHNRs</b>

Vanadium-Containing Chloroperoxidase-Catalyzed Versatile Valorization of Phenols and Phenolic Acids

The downstream product transformation of lignin depolymerization is of great interest in the production of high-value aromatic chemicals. However, this transformation is often impeded by chemical oxidation under harsh reaction conditions. In this study, we demonstrate that hypohalites generated in situ by the vanadium-containing chloroperoxidase from Curvularia inaequalis (CiVCPO) can halogenate various electron-rich and electron-poor phenol and phenolic acid substrates. Specifically, CiVCPO enabled decarboxylative halogenation, deformylative halogenation, halogenation, and direct oxidation reactions. The versatile transformation routes for the valorization of phenolic compounds showed up to 99% conversion and 99% selectivity, with a turnover number of 60,700 and a turnover frequency of 60 s–1 for CiVCPO. This study potentially expands the biocatalytic toolbox for lignin valorization