Heterogeneous Fenton system driven by iron-loaded sludge biochar for sulfamethoxazole-containing wastewater treatment.

In this study, the treatment performance of a heterogeneous Fenton system (Fe-BC + H2O2) driven by iron-loaded sludge biochar (Fe-BC) on wastewater containing sulfamethoxazole (SMX) was investigated using the CODcr removal efficiency (φ) as an indicator. The batch experimental results showed that the optimal operating conditions were as follow: initial pH 3, H2O2 concentration 20 mmol L-1, Fe-BC dose 1.2 g L-1, temperature 298 K. The corresponding φ was as high as 83.43%. The removal of CODcr was better described by BMG model and revised BMG (BMGL) model. According to the BMGL model, the φmax could be 98.37% (298 K). Moreover, the removal of CODcr was a diffusion-controlled process, while liquid film diffusion and intraparticle diffusion together determined its removal rate. The removal of CODcr should be a synergistic effect of adsorption and Fenton oxidation (real heterogeneous Fenton and homogeneous Fenton) and other pathways. Their contributions were 42.79%, 54.01% and 3.20%, respectively. For homogeneous Fenton, there seemed to be two simultaneous SMX degradation pathways: SMX→4-(pyrrolidine-11-sulfonyl)-aniline→N-(4-aminobenzenesulfonyl) acetamide/4-amino-N-ethyl benzene sulfonamides→4-amino-N-hydroxy benzene sulfonamides; SMX→N-ethyl-3-amino benzene sulfonamides→4-methanesulfonylaniline. In summary, Fe-BC had potential for practical application as a heterogeneous Fenton catalyst.

Anticorrosion and dispersive adsorption studies of natural andrographolide on carbon steel in acid-chloride environments.

Andrographolide, a bioactive naturally occurring labdane diterpenoid with outstanding antioxidant effects in medicine, has been isolated and purified from Andrographis paniculata, and applied in acid-chloride environments for the corrosion protection of carbon steel. Upon isolation, the phytochemical was identified by NMR and FTIR, while its corrosion inhibition evaluation was achieved by combined electrochemical and gravimetric experiments. The adsorption of andrographolide on carbon steel was examined by SEM, FTIR, and 3D surface measurement, and computational studies were used to describe the adsorption characteristics and properties. The experimental measurements revealed that andrographolide is an effective mixed-type corrosion inhibitor whose efficiency was dependent on both its concentration and the temperature of the environment, with maximum inhibition efficiency of 92.4% recorded for 2.0 g/L andrographolide after 48 h at 318 K. The adsorption of andrographolide and its anticorrosion capacity on carbon steel surface was confirmed by the employed surface analytical techniques, while molecular electrostatic potential, conceptual density functional theory, and molecular dynamics simulation predicted the quantum chemical details and binding properties of the phytochemical on Fe (110) surface at different temperatures.

Influence of fluorinated graphene-modified epoxy coatings on the corrosion behaviour of 2024 aluminium alloy.

This study provides an enhanced corrosion resistance of epoxy resin (EP) by embedding fluorinated graphene (FG) into the epoxy matrix. FG with different fluorine contents was obtained by reacting nitrogen trifluoride (NF3) gas with GO and then incorporated into the EP matrix to fabricate the different composites. Through a series of characterization methods, the chemical composition and microstructures of FG were systematically analyzed, and its corrosion resistance was also studied. Results revealed that F atoms were bonded to the GO surface to form C-F covalent bonds, and an FG lamellar thickness less than 2 nm. The contact angle of the coatings increased with the incorporation of FG, and the coating resistance of FG2/EP coating was 3 orders of magnitude more than that of the EP coating after immersion for 4080 h. Thus, the incorporation of FG into epoxy matrix significantly enhanced its hydrophobic properties and barrier performance, which was beneficial to improving the long-term corrosion resistance of the coating.

Assembly of heteropoly acid into localized porous structures for in situ preparation of silver and polypyrrole nanoparticles.

A simple and facile method to fabricate porous films which were locally patterned by heteropoly acid was developed in this study. The mixture of poly(methyl methacrylate) and stabilizer dichloromethane solution which contains heteropoly acid aqueous solution, prepared through shaking, was applied to fabricate a reversed microemulsion. After spreading and evaporating the solvent of microemulsion on a glass slide, an ordered honeycomb film was produced by incorporation of heteropoly acid in the cavities. The locally anchored heteropoly acid could be readily applied for the selective modification of the porous films through the in situ chemical reactions in the cavities with the additive agents. The silver nanoparticles were in situ prepared via the reduction of silver ions by reduced state H3PW12O40, and the polypyrrole spheres were locally obtained through the oxidative polymerization of pyrrole catalyzed by H3PMo12O40 in the cavities. Considering that water-soluble molecules and nanoparticles were universally suitable for the present strategy, the reported approach opened up an efficient way for patterning organically incompatible components on porous polymer films via the assembly of microemulsion droplet carriers to fabricate multi-functional hybrid surface structures.

Interaction between fullerenes and single-wall carbon nanotubes: the influence of fullerene size and electronic structure.

A series of fullerenes and endohedral metallofullerenes peapods have been synthesized by supercritical method in high filling rate. The interaction between SWNTs and various kinds of fullerenes (C60, C70, C78, C84) and metallofullerenes (Gd@C82, Er@C82, Ho@C82, Y@C82) has been further investigated. The slight blue shift of G-band in Raman spectra with respect to pristine SWNTs was attributed to the charge transfer from SWNTs to fullerenes cage. The obvious RBM shift strongly depended on the distance between the inner wall of the SWNTs and the fullerene cage and also partly associated with the electronic structure of the fullerene. These results indicated that the interaction between fullerenes and SWNTs, which was considered to be the van de walls interaction, can be influenced by the cage size and the kind of fullerenes.

Structural change of metallofullerene: an easier thermal decomposition.

We have studied for the first time the structural change of high-purity metallofullerene (Gd@C(82)) upon heat treatment in an ultra-high vacuum system (10(-10) Torr) and examined the decomposition product through successive analysis with MS, IR, Raman, TEM, EDS and XPS. It was found that metallofullerene (Gd@C(82)) had fully collapsed at 580 °C which was lower than that for the complete destruction of C(60). The easier decomposition should be ascribed to the encapsulated metal in the carbon cage which could induce the deformation of the C-C bond. The analysis indicated that the broken metallofullerene (Gd@C(82)) became a kind of graphite-like material with a lot of defects. The Gd atoms leaked out from the carbon cage and aggregated together to form a regular arrangement.

Supercritical synthesis and characterization of SWNT-based one dimensional nanomaterials.

The present study developed a novel, fast and efficient method to synthesize one dimensional nanotube-based materials via supercritical reactions and supercritical fluids. It was proved that supercritical organic fluids were good media to take materials into the nanocavity, not only as solvents but also as reaction agents. Different kinds of metals (Ni, Cu, Ag) and fullerenes (C(60), C(70), C(78), C(84), Gd@C(82), Er@C(82), Ho@C(82), Y@C(82)) were successfully inserted into nanotubes with small diameters by this technique, with various supercritical fluids such as C(2)H(5)OH, CH(3)OH or C(6)H(5)CH(3). The filling rates were proved to be more than 90%. The high filling efficiency and the properties of the as-generated materials were characterized by TEM, Raman, EDS and XPS. In principle, this technique can be applied to construct new types of nanomaterials, if we choose the appropriate supercritical reaction and fluid in the CNTs.

Self-construction of core-shell structure by metallofullerene-containing polymer.

Metallofullerene Gd@C82 offers the opportunity to produce novel and advanced polymer-based nanocomposite materials. In this work, we reported the synthesis of novel Gd@C82-containing copolymers with the optimum condition found by changing the temperature, initiator and fullerene contents of C60-PS. The developed materials, based on polystyrene, displayed unique nanostructures which were confirmed by many measurements (GPC, AFM, SEM, TGA/DSC and NEXAFS analysis). The mechanism, stability and structure of Gd@C82-containing copolymer were discussed. This approach offers a new possibility of optimizing the polymer performance with metallofullerene.