Liang Lv

Effect of functionalized multi-walled carbon nanotubes on the microstructure and performances of PVDF membranes

Functionalized multi-walled carbon nanotubes (f-MWCNTs) were synthesized by grafting carboxyl groups and 3-aminopropyltriethoxysilane (APTS) on the nanotube surface, respectively. A novel polyvinylidene fluoride (PVDF) membrane was prepared by incorporation of different dosages of APTS modified MWCNTs (A-MWCNTs) via the phase-inversion method. The dispersity of MWCNTs and compatibility between MWCNTs and the polymer matrix were enhanced after functional modification. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) testing showed that A-MWCNTs/PVDF blend membranes exhibited superior surface morphology and pore structure. Because of a strong interfacial interaction with the PVDF matrix, the mechanical strength of PVDF membranes was improved by adding A-MWCNTs and the optimum addition content was 2 wt%. More importantly, the bovine serum albumin (BSA) rejection of membranes increased significantly from 64.2% (nascent PVDF membranes) to 92.48% (A-MWCNTs/PVDF), which was attributed to the network structure of APTS. It can be expected that the blending modification of PVDF membranes by f-MWCNTs will have a bright and foreseeable application prospect.

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.

Study on the catalytic effect of ErCrO3 nanoparticles on the thermal decomposition of ammonia perchlorate

Orthorhombic structure perovskite ErCrO3 nanocrystals were prepared by glycine combustion method. The ErCrO3 nanocrystals were characterized by XRD, SEM, and BET. The catalytic activity measurements were carried out by DSC and TG-MS. The results indicate that ErCrO3 nanoparticles have an intense catalytic effect on the decomposition of AP. Adding 2% of ErCrO3 obtained product to AP decreases the decomposition temperature by 82°C and increases the heat of decomposition by 0.6 kJ g−1. Gaseous products of thermal decomposition of AP were NH3, H2O, O2, HCl, NO, HNO, N2O, NO2, and Cl2. The mechanism of catalytic action is based on the presence of superoxide ion (O2−) and oxygenic ion (O−, O2−) on the surface of ErCrO3, and they can accelerate the thermal decomposition process of AP and the oxidation of NH3.

Attached β-cyclodextrin/γ-(2,3-epoxypropoxy) propyl trimethoxysilane to graphene oxide and its application in copper removal

The environmental applications of graphene oxide and β-cyclodextrin (β-CD) have attracted great attention since their first discovery. Novel nanocomposites were successfully prepared by using an esterification reaction between β-cyclodextrin/γ-(2,3-epoxypropoxy) propyl trimethoxysilane grafted graphene oxide (β-CD/GPTMS/GO). The β-CD/GPTMS/GO nanocomposites were used to remove the Cu2+ from aqueous solutions. The characteristics of β-CD/GPTMS/GO were detected by scanning electron microscopy (SEM), Fourier transform infrared, X-ray diffraction (XRD), thermogravimetric analysis (TG) and energy dispersive X-ray (EDX). The dispersibility of graphene oxide was excellent due to the addition of β-CD. The adsorption isotherms data obtained at the optimum pH 7 were fitted by Langmuir isotherm model. The excellent adsorption properties of β-CD/GPTMS/GO for Cu2+ ions could be attributed to the apolar cavity structure of β-CD, the high surface area and abundant functional groups on the surface of GO. The adsorption patterns of β-CD/GPTMS/GO were electrostatic attraction, formation of host-guest inclusion complexes and the ion exchange adsorption. The efficient adsorption of β-CD/GPTMS/GO for Cu2+ ions suggested that these novel nanocomposites may be ideal candidates for removing other cation pollutants from waste water.