Haihui Di

Covalent modification of graphene oxide by metronidazole for reinforced anti-corrosion properties of epoxy coatings

Graphene can be used as an excellent protection material because of its barrier properties. This work reports a promising application of metronidazole (MET) modified graphene oxide (GO) composites (GME) for the corrosion protection of steel. The composites were synthesized using the carboxyl group of GO and hydroxyl group of MET with the help of maleic anhydride (MA), dispersing these sheets into epoxy resin at a low weight fraction of 0.2 wt%. A UV-vis absorption spectrum revealed that MET can be detected in NaCl (3.5 wt%) solution. An electrochemical impedance spectroscopy (EIS) test showed that the corrosion resistance performance is significantly enhanced by the addition of GME hybrids to epoxy compared to GO. A scratch test illustrated that fewer corrosion products formed in the scratch on the steel coated by GME. The strategy of using corrosion inhibitor modified graphene oxide can be extended to develop new graphene-based materials with other excellent materials for the protection of metal components.

Preparation of a novel anti-fouling β-cyclodextrin–PVDF membrane

As part of this work, polyvinylidene fluoride (PVDF) membranes were prepared via a phase inversion method. A novel β-cyclodextrin (β-CD)–PVDF membrane was prepared via an interfacial reaction, using Trimesoyl Chloride (TMC) and β-CD as cross-linking and modification agents, respectively. The membranes were modified by a simple dip-coating method. The results of comparison between the modified and unmodified membranes by attenuated total reflectance Fourier transform infrared spectroscopy (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS) methods confirmed successful grafting of β-CD on the membrane surfaces. The morphology of the membrane was investigated by scanning electron microscopy (SEM) and atomic-force microscopy (AFM). The roughness of PVDF membranes increased after their surfaces were grafted with β-CD. It was also found that β-CD–PVDF membranes had higher permeate flux and hydrophilicity than those of the pristine PVDF membranes. Furthermore, in protein fouling experiments, bovine serum albumin (BSA) was used as a protein model solution. Modified membranes exhibited a higher flux recovery ratio. The experiment showed that the anti-fouling performance of β-CD–PVDF membranes was more effective in reducing the irreversible membrane fouling. The results of this study hold promise for useful applications of β-CD–PVDF membranes in membrane separation areas.