Improved performance of polymer light-emitting diodes with nanocomposites

The characteristics of a hybrid polymer light-emitting diode (HPLED) with an active layer of poly [2-methoxy,5-(2-ethylhexoxy)-1,4-phenylenevinylene] blended with Au-capped TiO(2) nanocomposites are reported. Both the increased current in the active layer and low turn-on voltage were attributed to incorporation of Au-capped TiO(2) in the electroluminescent polymer. The maximal brightness of 11 630 cd/m(2) was observed in HPLED with a 1:1 ratio of Au-capped TiO(2). The enhanced performance was attributed to the roughness assisted charge transport induced by the Au-capped TiO(2) nanocomposites in the active polymer.open111

A review of combined advanced oxidation technologies for the removal of organic pollutants from water

Water pollution through natural and anthropogenic activities has become a global problem causing short-and long-term impact on human and ecosystems. Substantial quantity of individual or mixtures of organic pollutants enter the surface water via point and nonpoint sources and thus affect the quality of freshwater. These pollutants are known to be toxic and difficult to remove by mere biological treatment. To date, most researches on the removal of organic pollutants from wastewater were based on the exploitation of individual treatment process. This single-treatment technology has inherent challenges and shortcomings with respect to efficiency and economics. Thus, application of two advanced treatment technologies characterized with high efficiency with respect to removal of primary and disinfection by-products in wastewater is desirable. This review article focuses on the application of integrated technologies such as electrohydraulic discharge with heterogeneous photocatalysts or sonophotocatalysis to remove target pollutants. The information gathered from more than 100 published articles, mostly laboratories studies, shows that process integration effectively remove and degrade recalcitrant toxic contaminants in wastewater better than single-technology processing. This review recommends an improvement on this technology (integrated electrohydraulic discharge with heterogeneous photocatalysts) viz-a-vis cost reduction in order to make it accessible and available in the rural and semi-urban settlement. Further recommendation includes development of an economic model to establish the cost implications of the combined technology. Proper monitoring, enforcement of the existing environmental regulations, and upgrading of current wastewater treatment plants with additional treatment steps such as photocatalysis and ozonation will greatly assist in the removal of environmental toxicants

Semiconductor Assisted Photodegradation of Textile Dye

224-230The degradation of commonly used textile dye reactive red 2 in an aqueous solution by means of photocatalysis using ZnO in the form of slurry is studied. The influence of initial concentration of the dye, pH of the reaction mixture. Catalyst loading, the presence of oxygen, hydrogen peroxide, and potassium persulphate on the degradation rate is observed. When concentration of the dye increases from 60 to 140 ppm, the rate constants vary between 0.055 and 0.019 min-1. The disappearance of the dye follows approximately pseudo-first order kinetics. For an irradiation time of 60 min, 86 per cent COD reduction is noted, whereas 100 per cent degradation observed at 300min of irradiation time. The oxidising agents (oxygen, hydrogen peroxide and potassium persulphate) enhance the degradation rate of the dye. Carbonate ions present in dye solution inhibit the degradation rate of the dye. This method suggests the possible use of ZnO photocatalysed degradation of textile dye present in wastewater

Graphene oxide based Pt\u2013TiO2 photocatalyst: Ultrasound assisted synthesis, characterization and catalytic efficiency

An ultrasound-assisted method was used for synthesizing nanosized Pt\u2013graphene oxide (GO)\u2013TiO2 photocatalyst. The Pt\u2013GO\u2013TiO2 nanoparticles were characterized by diffused reflectance spectroscopy, X-ray diffraction, N2 BET adsorption\u2013desorption measurements, atomic force microscopy and transmission electron microscopy. The photocatalytic and sonophotocatalytic degradation of a commonly used anionic surfactant, dodecylbenzenesulfonate (DBS), in aqueous solution was carried out using Pt\u2013GO\u2013TiO2 nanoparticles in order to evaluate the photocatalytic efficiency. For comparison purpose, sonolytic degradation of DBS was carried out. The Pt\u2013GO\u2013TiO2 catalyst degraded DBS at a higher rate than P\u201325 (TiO2), prepared TiO2 or GO\u2013TiO2 photocatalysts. The mineralization of DBS was enhanced by a factor of 3 using Pt\u2013GO\u2013TiO2 compared to the P\u201325 (TiO2). In the presence of GO, an enhanced rate of DBS oxidation was observed and, when doped with platinum, mineralization of DBS was further enhanced. The Pt\u2013GO\u2013TiO2 catalyst also showed a considerable amount of degradation of DBS under visible light irradiation. The initial solution pH had an effect on the rate of photocatalytic oxidation of DBS, whereas no such effect of initial pH was observed in the sonochemical or sonophotocatalytic oxidation of DBS. The intermediate products formed during the degradation of DBS were monitored using electrospray mass spectrometry. The ability of GO to serve as a solid support to anchor platinum particles on GO\u2013TiO2 is useful in developing new photocatalysts