The Design Synthesis Of The Graphene Composites Modified By Covalent Bond And Their Applications In The Environment

New nanoscale hybrid materials based on nanoparticles and graphene were designed and fabricated by the methods of the coordination bond and assembly, and their properties were studied. Palladium Nanoparticles decorated on 2D magnetic reduced grapheme oxide nanocomposites were prepared and further investigated in the catalytic degradation in aqueous solution. The obtained nanocompostie structures were characterized by some techniques to explore their promising applications in the fields like environment and colorimetric detection. Meanwhile, two hydrazone derivative materials were designed and synthesized by Schiff-base. Due to its specific structure and coordination sites, aluminum ions could be binded by hydrazone Schiff-base derivatives to form aluminum complex, w hich display excellent optical performance. They can be used as a potential and excellent fluorescent chemosensor for Al3+ detection in environmental areas. Therefore, we believe that such features provide a method for the coordination bond modified materials in environment ?elds. The main results are as below:1. We have successfully synthesized the Pd/Fe3O4-PEI-RGO ternary nanohybrids with high shape selectivity and high specific surface area by high dispersion of Pd NPs and Fe3O4 NPs on the PEI modified graphene oxide sheets. PEI-RGO was firstly synthesized by amidation reaction between PEI and GO. PEI-RGO reacted with 3,4-dihydroxybenzaldehyde to form DIB-PEI-RGO and then Fe3O4 NPs was added into DIB-PEI-RGO to prepare Fe3O4-DIB-PEI-RGO. Finally, Pd NPs/Fe3O4-DIB-PEI-RGO was obtained by adding Na BH4 to the aqueous solution of PdCl2 and Fe3O4-DIB-PEI-RGO. The noble-metal nanocatalyst on the magnetic support has a very low leaching loss and excellent reusability for cycles. More importantly, the PEI modified graphene oxide sheets enhance the wetting ability of grapheme and good size monodispersity of NPs on grapheme oxide via coordination bonds.2. The application of nanohybrids in water treatment by the catalytic degradation of various pollutants has attracted much attention from researchers. The Pd/Fe3O4-PEI-RGO nanohybrids show superior catalytic activity toward MB, MO and RB with a high degradation efficiency in the presence of NaBH4 in aqueous solution, which is attributed to the effects of the Pd NPs supported on reduced graphene oxide nanosheets. Meanwhile, the catalyst can be easily separated from the reaction mixture by applying an external magnetic ?eld. The catalyst was recycled over nine times without showing a signi?cant loss in its activity.3. Pd/Fe3O4-PEI-RGO nanohybrid was found to possess superior peroxidase-like activity, and could ef?ciently oxidize 3,3′,5,5′-Tetramethylbenzidine(TMB) by hydrogen peroxide(H2O2) to produce a color reaction. Therefore, this provides a sensing platform for the colorimetric detection of H2O2 in solution. The linear range for H2O2 was from 0.5 to 150 μM and the limit of detection was as low as 0.1 μM.4. 2-acetyl-3-methylpyrazine nicotinic hydrazone(HAMPNH) and 2-benzoylpyridine benzoyl hydrazone(HBP BH) fluorescent chemosensor were designed and fabricated by a facile one-step Schiff base reaction. Due to its specific structure and coordination sites, aluminum ions could be binded by the two hydrazone Schiff-base derivatives to form aluminum complex. Therefore, they display excellent selectivity over other metal ions and sensitivity towards Al3+ with a low detection limit of 10-7 M level in ethanol. These suggest that they can be used as a potential and excellent fluorescent chemosensor for Al3+ detection in environmental areas. They display remarkable optical properties, and could be highly applied in the optical fields. Therefore, such features enable the optical properties for promising application in optical material ?elds.