Graphene oxide aerogel assembled by dimethylaminopropylamine /N-isopropylethylenediamine for the removal of copper ions

Graphene Oxide Monolith composites (GOMs) were prepared using dimethylaminopropylamine (DMPDA) and N-isopropylethylenediamine (IPEDA) with one-step method in water medium, respectively. Fourier transform-infrared (FTIR), X-Ray Diffraction (XRD) tests proved the formation of new structure and credible interactions between crosslinkers and GO. Scanning electron microscopy (SEM) showed distinct change of morphology after complexing. Bath adsorption tests suggested that the fast adsorption of copper ions (II) was strongly affected by pH, ionic strength, temperature, and concentration, etc.. Isothermal Langmuir and Freundlich kinetic model showed the different degree of fitting conformity according to different conditions. SEM and XRD further provided a supporter of adsorption of copper ions onto GOMs, and Density functional theory (DFT) was used to analyze the crosslinking details of DMPDA and GO and the adsorption mechanism of copper ions. The theoretical calculation results clarified an efficacious and quantitative understanding for the crosslinking and adsorption mechanism.

Corrosion resistance of itaconic acid doped polyaniline /nanographene oxide composite coating

Graphene oxide (GO) and polyaniline (PANI) are very unique materials with broad potential in corrosion protection coating. To achieve the maximum stability and anti-corrosion effect in a polar medium, firstly itaconic acid doped PANI (DP) was readily prepared by a one-step method, followed by forming a GO and DP composite (GODP). Characterization by Fourier transform infrared spectroscopy and ultraviolet-visible absorption spectra provides evidence for the successful doping of itaconic acid in PANI. X-ray diffraction analysis shows that the d-spacing of the GO sheets increases slightly with the intercalation of DP. The morphological studies show disordered structures in GODP compared with the original GO sheets due to the introduction of PANI molecules and the interaction of functional groups on the surface of the GO sheets. Thermogravimetric analysis reveals the good thermal stability of DP and GODP. Quantum calculation further confirms the successful doping of itaconic acid, and the effective complex of GO and DP, providing a quantitative understanding of the curing mechanism. The crosslinking interaction among the GODP, curing agent, and epoxy resin facilitates the formation of a compact coating, leading to excellent corrosion resistance toward Mg alloy.

Nitrogen-doped graphene oxide monoliths crosslinked by short chain aliphatic amines

Nitrogen-doped graphene oxide monoliths (NGOMs) were readily fabricated by crosslinking graphene oxide (GO) using four different short chain aliphatic amines, i.e., ethylenediamine (EDA), dimethylaminopropylamine (DMPDA), N-isopropylethylenediamine (IPEDA), and triethylenetetramine (TETA). Depending on the structure of the amine crosslinkers, the generated monoliths showed various morphologies with different d spacing, layer thickness, and microspore size. Fourier transform-infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses provided evidence for the formation of covalent CN or CN bonds in all cases, indicating that the interaction of GO with amine crosslinkers involved the ring-opening reaction between GO epoxides and amine groups. The formation of both quaternary nitrogen and some nitrogen-containing heterocyclic composition inside the graphene oxide sheet were also suggested. X-Ray Diffraction (XRD) results indicated that the interspatial distance between GO sheets was increased after crosslinking. The fabricated NGOM-TETA demonstrates potential application as an adsorbent material due to its efficient removal of copper ions.