[Show abstract][Hide abstract] ABSTRACT: Anionic polystyrene (PSt) latex particles were synthesized by emulsion polymerization of methacrylic acid and styrene (St). The anionic PSt particles were surface treated with vinyl trimethoxysilane in a mixture of ethanol and water. PSt/TiO2 composite particles doped with Ag2O were then prepared through hydrolysis of tetrabutyl titanate and AgNO3 using the surface treated PSt particles as templates. Hollow Ag-TiO2 particles were successfully prepared by treating the PSt/TiO2 composite microspheres at 180 °C, after which they were dried and calcined at 500 °C. The morphology of the PSt/TiO2 particles and crystal structure of the Ag-TiO2 hollow particles were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Photocatalytic activity of the Ag-TiO2 hollow particles for Rhodamine B (RhB) degradation was tested under ultraviolet (UV, 365 nm) and UV-visible (370-760 nm) light. Under UV light, RhB degradation was increased by about 11% when Ag-TiO2 particles with molar ratio nAg/nTi of 0.1% were used compared with pure TiO2 hollow particles. Under UV-visible light, RhB degradation was increased by about 30% for Ag-TiO2 composite particles with nAg/nTi of 1.0% and 2.0%.
[Show abstract][Hide abstract] ABSTRACT: A novel single-step synthetic method for the preparation of anatase N-doped TiO2 nanocrystalline at low temperature has been devoleped. The N-doped anatase TiO2 nanoparticles were synthesized by sonication of the solution of tetraisopropyl titanium and urea in water and isopropyl alcohol at 80°C for 150min. The as-prepared sample was characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and UV–vis absorption spectrum. The product structure depends on the reaction temperature and reaction time. The photocatalytic activity of the as-prepared photocatalyst was evaluated via the photodegradation of an azo dye direct sky blue 5B. The results show that the N-doped TiO2 nanocrystalline prepared via sonication exhibit an excellent photocatalytic activity under UV light and simulated sunlight.
No preview · Article · Nov 2011 · Materials Research Bulletin
[Show abstract][Hide abstract] ABSTRACT: The ultrasonic degradation of reactive brilliant red K-2BP (K-2BP) in water with CCl4 enhancement was investigated. The effects of operating parameters, such as CCl4 dosage, ultrasonic power, media temperature, dye initial concentration, and initial media pH on K-2BP degradation were discussed. The ultrasonic degradation of K-2BP was obviously enhanced by CCl4 addition – an effect attributed to the increased OH radical concentration in the presence of CCl4 as a hydrogen atom scavenger, and the formation of chlorine-containing radicals. The main degradation products of K-2BP were tentatively identified by GC–MS and ion chromatography. A possible degradation pathway for K-2BP was also proposed.
No preview · Article · Jul 2011 · Separation and Purification Technology
[Show abstract][Hide abstract] ABSTRACT: In this paper, the photocatalytic activity of AgCl catalyst in water under the UV and simulated sunlight irradiation was investigated. The AgCl catalyst was obtained by the reaction of AgNO3 with NaCl in water. The photocatalytic activity of the catalyst was evaluated by the photocatalytic degradation of a azo dye direct sky blue 5B in aqueous solution. The result showed that AgCl photocatalyst was able to effectively photocatalytic degrada direct sky blue 5B dye.
[Show abstract][Hide abstract] ABSTRACT: The sonochemical synthesis of silver nanorods has been achieved by ultrasonic irradiation of the aqueous solution of silver nitrate, methenamine (HMTA) and poly (vinyl pyrrolidone) (PVP) for 60 min. The silver nanorods obtained have lengths of 4-7 microm and mean diameters of about 100 nm. The structures of the samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), selected area electron diffraction (SAED) and X-ray powder diffraction (XRD), and the chemical composition of the sample was examined by energy-dispersive X-ray spectrum (EDS). The effects of the irradiation time, the concentration of PVP and the reaction temperature on the morphology of silver nanorods were discussed, and the mechanism of the silver nanorods formation was tentatively inferred.
No preview · Article · Apr 2010 · Ultrasonics Sonochemistry
[Show abstract][Hide abstract] ABSTRACT: In this paper, a simple and effective route for the synthesis of silver dendritic nanostructures by means of ultrasonic irradiation has been developed. Well-defined silver dendritic nanostructures were obtained by sonicating the aqueous solution of 0.04mol/L silver nitrate with 4.0mol/L isopropanol as reducing agent and 0.01mol/L PEG400 as disperser for 2h. The effects of the irradiation time, the concentration of Ag(+) and the molar ratio of PEG to AgNO(3) on the morphology of silver nanostructures were discussed. The structures of the obtained samples were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED) and X-ray powder diffraction (XRD), and the chemical composition of the dendrites was examined by energy-dispersive X-ray spectrum (EDS).
No preview · Article · Apr 2009 · Ultrasonics Sonochemistry