A simple solvothermal method was used to prepare monodisperse magnetite (Fe3O4) nanoparticles attached onto graphene oxide (GO) sheets as adsorbents to remove tetrabromobisphenol A (TBBPA) from an aqueous solution. These Fe3O4/GO (MGO) nanocomposites were characterized by transmission electron microscopy. The adsorption capacity at different initial pH, contact duration, and temperature were evaluated. The kinetics of adsorption was found to fit the pseudo-second-order model perfectly. The adsorption isotherm well fitted the Langmuir model, and the theoretical maximum of adsorption capacity calculated by the Langmuir model was 27.26 mg?g-1. The adsorption thermodynamics of TBBPA on the MGO nanocomposites was determined at 303 K, 313 K, and 323 K, respectively. The results indicated that the adsorption was spontaneous and endothermic. The MGO nanocomposites were conveniently separated from the media by an external magnetic field within several seconds, and then regenerated in 0.2 M NaOH solution. Thus, the MGO nanocomposites are a promising candidate for TBBPA removal from wastewater. 相似文献
Motivated by the recent realization of graphene sensor to detect gas molecules that are harmful to the environment, the ammonia adsorption on graphene or graphene oxide (GO) was investigated using first-principles calculation. The optimal adsorption and orientation of the NH3 molecules on the graphene surfaces were determined, and the adsorption energies (Eb) as well as the Mulliken charge transfers of NH3 were calculated. The Eb for the graphene are small and seem to be independent of the sites and orientations. The surface epoxy or hydroxyl groups can promote the adsorption of NH3 on the GO; the enhancement of the Eb for the hydroxyl groups is greater than that for the epoxy groups on the surface. The charge transfers from the molecule to the surfaces also exhibit the same trend. The Brönsted acid sites and Lewis acid sites could stably exist on the GO with surface hydroxyl groups and on the basal, respectively. 相似文献
N-doped reduced graphene oxide quantum dots(N-rGQDs) have attracted more and more attention in efficient catalytic degradation of aqueous organic pollutants. However, the synthesis of N-rGQDs is generally a complex and high energy required process for the reduction and N-doping steps. In this study, a facile and green fabrication approach of N-rGQDs is established, based on a metal-free Fenton reaction without additional energy-input. The N structures of N-rGQDs play a significant role in the pr... 相似文献
A new type of Au/TiO2/reduced graphene oxide (RGO) nanocomposite was fabricated by the hydrothermal synthesis of TiO2 on graphene oxide followed by the photodeposition of Au nanoparticles. Transmission electron microscopy images showed that Au nanoparticles were loaded onto the surface of both TiO2 and RGO. Au/TiO2/RGO had a better photocatalytic activity than Au/ TiO2 for the degradation of phenol. Electrochemical measurements indicated that Au/TiO2/RGO had an improved charge transfer capability. Meanwhile, chemiluminescent analysis and electron spin resonance spectroscopy revealed that Au/TiO2/RGO displayed high production of hydrogen peroxide and hydroxyl radicals in the photocatalytic process. This high photocatalytic performance was achieved via the addition of RGO in Au/TiO2/RGO, where RGO served not only as a catalyst support to provide more sites for the deposition of Au nanoparticles but also as a collector to accept electrons from TiO2 to effectively reduce photogenerated charge recombination.
We demonstrated a complete decomposition method for ionic liquids (ILs; organic cation part: butyl-methyl or ethyl-methyl
imidazolium, and inorganic anion part: PF6 −, BF4− or Br−) in aqueous media by combining a hydrothermal mineralization method with a photocatalytic decomposition (PD) method. As a
result, the hydrothermal treatment with Ca(OH)2 mineralizer could effectively remove the inorganic anion part, such as PF6− or BF4− and the PD could decompose the organic cation part effectively. Therefore, the detoxification of ILs in aqueous media was
accomplished by the present method. 相似文献
Microplastics have recently become a major environmental issue due to their ubiquitous distribution, uncontrolled environmental occurrences, small sizes and long lifetimes. Actual remediation methods include filtration, incineration and advanced oxidation processes such as ozonation, but those methods require high energy or generate unwanted by-products. Here we tested the degradation of fragmented, low-density polyethylene (LDPE) microplastic residues, by visible light-induced heterogeneous photocatalysis activated by zinc oxide nanorods. The reaction was monitored using Fourier-transform infrared spectroscopy, dynamic mechanical analyser and optical imaging. Results show a 30% increase of the carbonyl index of residues, and an increase of brittleness accompanied by a large number of wrinkles, cracks and cavities on the surface. The degree of oxidation was directly proportional to the catalyst surface area. A mechanism for polyethylene degradation is proposed.
Defect-engineered carbon materials have been emerged as promising electrocatalysts for oxygen reduction reaction(ORR) in metal-air batteries. Developing a facile strategy for the preparation of highly active nanocarbon electrocatalysts remains challenging. Herein, a low-cost and simple route is developed to synthesize defective graphene by pyrolyzing the mixture of glucose and carbon nitride. Molecular dynamics simulations reveal that the graphene formation is ascribed to two-dimensional layered... 相似文献
