A flame-retardant composite was synthesized through a simple graphene oxide functionalization route with hexachlorocyclotriphosphazene and p-phenylenediamine. Flame experiments conducted on the synthesized composite proved its importance as tremendously resistant to fire. The thermogravimetric analysis (TGA) shows clearly that the functionalized graphene oxide (FGO) exhibits an enhanced thermal stability and better temperature resistance. A thermoset epoxy resin was prepared by incorporating different percentages (2, 5, and 10%) of FGO to diglycidyl ether of bisphenol A (DGEBA). The flame-retardant properties, thermal degradation behavior, and combustion of the DGEBA thermosets cured by m-phenylenediamine were investigated using a Bunsen burner flame approaching the flame temperature of a fire and TGA. The chemical structure of FGO was characterized with spectroscopic and imaging techniques including Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, TGA, scanning electron microscopy, energy-dispersive X-ray spectroscopy elemental mapping, and X-ray photoelectron spectroscopy. Due to its high flame-retardant capabilities, such a composite could promise potential applications in the manufacture of inflammable materials for different uses.

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Core–shell magnetic covalent organic framework (COF) materials were prepared, followed by shell material functionalization with different organic ligands, including thiosemicarbazide, through a postsynthetic modification approach. The structures of the prepared samples were characterized with various techniques, including powder X-ray diffraction (PXRD), Brunauer–Emmett–Teller (BET) method, thermogravimetric analysis (TGA), photoinduced force microscopy (PiFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and solid 13C NMR. PXRD and BET studies revealed that the crystalline and porous nature of the functionalized COFs was well maintained after three steps of postsynthetic modification. On the other hand, solid 13C NMR, TGA, and PiFM analyses confirmed the successful functionalization of COF materials with good covalent linkage connectivity. The use of the resulting functionalized magnetic COF for selective and ultrafast adsorption of Hg(II) has been investigated. The observations displayed rapid kinetics with adsorption dynamics conforming to the quasi-second-order kinetic model and the Langmuir adsorption model. Furthermore, this prepared crystalline magnetic material demonstrated a high Langmuir Hg(II) uptake capacity, reaching equilibrium in only 5 min. Thermodynamic calculations proved that the adsorption process is endothermic and spontaneous.