Advanced Materials Research Vols. 734-737

Abstract: Fe3O4 nanoparticles (Fe3O4 NPs) were successfully prepared via chemical co-precipitation method under the assistance of ultrasound irradiation and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). a series of experiments were carried out to investigate the degradation of Rhodamine B(RhB) by the obtained heterogeneous Fe3O4 catalysts in the presence of H2O2. The effects of catalyst loading,initial pH, reaction temperature, oxidant concentration were discussed. The result indicated that the optimal conditions were Fe3O4 NPs dosage 0.7 g/L, initial pH=3.0, reaction temperature 60°C, oxidant concentration 20 mmol /L.

Abstract: Ag-doped BiVO₄ semiconductor photocatalysts were synthesized via the one-step hydrothermal method. The microstructure and morphology of catalysts were characterized by using X-ray diffraction, Scanning electron microscopy, and Energy dispersive X-ray detector (EDS) and photocatalytic activities of BiVO₄ catalysts with and without Ag doping were evaluated by degrading methylene blue (MB) under visible-light irradiation. UV-Vis absorption spectra were measured to evaulate the photocatalytic activity of the as-synthesized catalysts. The results suggested that Ag-doped BiVO₄ with larger rod-like particle size but better crystallnity has the stronger UV absorption. In comparison with pure BiVO4, degradation rate of MB was increased about 18% in Ag-doped BiVO₄ with the Ag⁺ dopant concentration of 15 mol%.

Abstract: A three-dimensional computational fluid dynamics (CFD) simulation was performed to study the velocity distribution on membrane surface in membrane separation process, and the effect of face permeability, porous medium thickness, and pressure-jump coefficient of porous-jump model on membrane flux. The study shows that all the three factors have important impact on membrane flux. Membrane flux increases linearly with the increase of face permeability. When the membrane thickness is between 0.04~0.1mm, the membrane flux decreases with the increase of membrane thickness. The membrane flux decreases with the increase of pressure-jump coefficient. So that there must be a complex relationship between membrane flux and face permeability, porous medium thickness, and pressure-jump coefficient.

Abstract: Due to the characteristics of the oilfield produced water, there are serious problems of corrosion and scale formation in the water recycling process. A compound inhibitor consists of organophosphine inhibitors and zinc sulfate, was applied to prevent corrosion and scale formation. The corrosion rate and scale inhibition efficiency were studied in artificial supersaturated solutions through weight loss measurements and static jar tests at 95°C, respectively. The results showed that the compound inhibitor had lower corrosion rate (0.021 mm/a) and higher scale inhibition efficiency (97.34 %). The result of industrial pilot test verified the compound inhibitor has an excellent efficiency at oilfield. All results show that the compound inhibitor can solve corrosion and scale formation in oilfield produced water recycling system.

Abstract: Chitosan has unique properties among biopolymers, especially due to the presence of several reactive groups, such as OH and NH₂, which can react with many compounds. Chitosan and its derivatives are able to chelate metal ions, eliminate free radicals and resist oxidation. The development of chitosan and its derivatives used as metal ions chelating agent and free radical scavenger was overviewed. In addition, the application of chitosan and its derivatives and their potentiality in paper industry was prospected.

Abstract: Ultrasound energy could strengthen the adsorption of dyes on fiber. The acceleration efficiency of ultrasound was investigated by dyeing cotton with reactive dyes. The experimental findings showed the accelerative efficiency of ultrasound decreased with the prolongation of dyeing time and increment of dyeing temperature. Ultrasound exhibited a better acceleration effect in high dye concentration. The use of ultrasound reduced about 27.2% Remazol red RGB and 50.3% Remazol yellow 3RS in dyeing wastewater.

Abstract: Polyphenol is a kind of active compound widely existed in many Chinese herbs, easily destroyed by oxygen and heat. Extraction and concentration are key steps to protect it from destruction, and the costly energy consumption steps in the process of herbs. In order to save energy and improve polyphenol quality, instantaneous ultrasonic extraction (IUE) and reverse osmosis (RO) concentration are evaluated in this paper. IUE and RO were used to extract polyphenol separately from herbs of Phyllantuus urinaria L, leaves of Camellia sinensis L and root of Salvia miltiorrhiza Bunge. Gallic acid, EGCG and Tanshinol, the main components of polyphenols, were determined by HPLC. Their content and energy consumption were compared to that by same time water boiling (10min) or 60min ultrasonic extraction and vacuum concentration. IUE increased 1-3 times or 1-5 times polyphenol content and saved 1 or 6 times energy consumption more than the same time water boiling or 60min ultrasonic extraction. Compared with vacuum vaporization to the same solid matter content (15%), RO increased 2 times polyphennol content and consumed 1/10 times energy and 1/5 times time. Combination of IUE and RO shortens process time, significantly improves polyphenol quality and saves energy. It will be the beneficial method for polyphenol extraction and concentration of Chinese herbs.

Abstract: Based on the experimental measurements of materials dielectric strength, this paper is focused on the relationships between dielectric strength of the materials and tensile stress applied on them. The experimental results indicated that the dielectric strengths of the unsaturated polyester resin and the unidirectional glass fiber reinforced composites had an obvious decrease compared with the samples without of it. Furthermore, the dielectric strength decreased with the increase of tensile stress. When tensile stress reached 50% of the material tensile strength, the dielectric strength of the resin decreased 13.36%, and the unidirectional glass fiber reinforced unsaturated polyester composites decreased 19.86% with the tensile stress in the longitudinal direction and 12.06% in the transverse direction. When the experimental samples were broken down by electricity, cracks and pores which would lead to stress concentration were created between the electrodes around the breaking-down point. In a word, it is vital to make a research about the effect of stress on the insulating properties of materials.

Abstract: Cotton and sulfuric acid that concentration is 98% as the raw material, to compare the resulting solid carbon sulfonic acid content of the material under different reaction temperatures. FTIR analysis shows that the cotton carbon is an amorphous carbon after sulfonation reactions, a sulfonic acid group present in the resulting material. When the sulfonation temperature is 170 °C, the prepared cotton carbon sulfonic acid has the highest acid content. By the sulfuric acid TG/DTG curve analysis, it verify: 170 °C is the highest activity temperature point of sulfuric acid sulfonation reaction.

Abstract: An efficiently brominated flame retardant which composed of decabromodiphenyl oxide (DB) and antimonous oxide (AO) was used to flame retardant for long glass fiber reinforced polypropylene (LGFPP). In order to investigate the thermal stability, flame retardancy and mechanical property of DB-AO/LGFPP composites used by thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical burning (UL-94) and mechanical property tests. The results showed that brominated flame retardant improved flame retardancy of LGFPP efficiently can be proved by TGA, and had less affected on mechanical properties.