Facile synthesis of light harvesting semiconductor bismuth oxychloride nano photo-catalysts for efficient removal of hazardous organic pollutants.

In the present work, bismuth oxychloride nanoparticles-a light harvesting semiconductor photocatalyst-were synthesized by a facile hydrolysis route, with sodium bismuthate and hydroxylammonium chloride as the precursor materials. The as-synthesized semiconductor photocatalysts were characterized using X-ray diffraction analysis, Fourier transform infra-red spectroscopy, Raman spectroscopy, Field emission scanning electron microscopy, X-ray photoelectron spectroscopy and Photoluminescence spectroscopy techniques. The crystal structure, morphology, composition, and optical properties of these facile synthesized bismuth oxychloride nanoparticles (BiOCl NPs) were compared to those of traditional bismuth oxychloride. In addition, the photocatalytic performance of facile-synthesized BiOCl NPs and traditional BiOCl, as applied to the removal of hazardous organic dyes under visible light illumination, is thoroughly investigated. Our results reveal that facile-synthesized BiOCl NPs display strong UV-Vis light adsorption, improved charge carrier mobility and an inhibited rate of charge carrier recombination, when compared to traditional BiOCl. These enhancements result in an improved photocatalytic degradation rate of hazardous organic dyes under UV-Vis irradiance. For instance, the facile-synthesized BiOCl NPs attained 100% degradation of methylene blue and methyl orange dyes in approximately 30 mins under UV-Vis irradiation, against 55% degradation for traditional BiOCl under similar experimental conditions.

Characterization of Environmental Dust in the Dammam Area and Mud After-Effects on Bisphenol-A Polycarbonate Sheets.

Owing to recent climate changes, dust storms are increasingly common, particularly in the Middle East region. Dust accumulation and subsequent mud formation on solid surfaces in humid environments typically have adverse effects on surface properties such as optical transmittance, surface texture, and microhardness. This is usually because the mud, which contains alkaline and ionic species, adheres strongly to the surface, often through chemical bonds, and is therefore difficult to remove. In this study, environmental dust and the after-effects of mud formed on a polycarbonate sheet, which is commonly used as a protective glass in photovoltaic cells. Ionic compounds (OH(-)) are shown to significantly affect the optical, mechanical, and textural characteristics of the polycarbonate surface, and to increase the adhesion work required to remove the dry mud from the polycarbonate surface upon drying. Such ability to modify characteristics of the polycarbonate surface could address the dust/mud-related limitations of superhydrophobic surfaces.

Influence of dust and mud on the optical, chemical, and mechanical properties of a pv protective glass.

Recent developments in climate change have increased the frequency of dust storms in the Middle East. Dust storms significantly influence the performances of solar energy harvesting systems, particularly (photovoltaic) PV systems. The characteristics of the dust and the mud formed from this dust are examined using various analytical tools, including optical, scanning electron, and atomic force microscopies, X-ray diffraction, energy spectroscopy, and Fourier transform infrared spectroscopy. The adhesion, cohesion and frictional forces present during the removal of dry mud from the glass surface are determined using a microtribometer. Alkali and alkaline earth metal compounds in the dust dissolve in water to form a chemically active solution at the glass surface. This solution modifies the texture of the glass surface, thereby increasing the microhardness and decreasing the transmittance of the incident optical radiation. The force required to remove the dry mud from the glass surface is high due to the cohesive forces that result from the dried mud solution at the interface between the mud and the glass. The ability altering the characteristics of the glass surface could address the dust/mud-related limitations of protective surfaces and has implications for efficiency enhancements in solar energy systems.

Removal of arsenic from water by iron oxide nanoparticles impregnated on carbon nanotubes.

The removal of Arsenic (As (III)) ions from water using modified multi-walled carbon nanotubes (MCNTs) was demonstrated in this study. Results of the study showed that raw (non-modified) MCNTs have very poor efficiency in removing As (III) from water by conventional adsorption mechanisms. However, when MCNTs were modified with iron oxide (Fe-MCNTs), a significant improvement in the As (III) removal efficiency was observed. Results of the study also showed that Fe-MCNTs have much higher efficiency in removing As (III) than MCNTs modified with carboxyl group (COOH-MCNTs). Under the experimental conditions used in the study, about 77.5% of As (III) removal was achieved by the Fe-MCNTs, while COOH-MCNTs removed only 11% at pH 5. In addition, the adsorption kinetics of MCNTs indicated that there is a strong affinity of As (III) ions to the surface of the Fe-MCNTs.

Kinetic study of laser-induced photocatalytic degradation of dye (alizarin yellow) from wastewater using nanostructured ZnO.

Nanoparticles of zinc oxide semiconductor were applied for removal of toxic organic pollutants such as dyes (alizarin yellow GG) from wastewater using laser induced photocatalytic process. A special photoreactor was designed for this purpose using local resources. Laser enhanced photo degradation of alizarin yellow GG (AYGG) was carried out by irradiating the contaminated aqueous solution with a 355 nm radiation generated from third harmonic of Nd:YAG laser. The effect of different operational parameters such as the initial dyes concentration, the concentration of photocatalyst, laser irradiation time, laser energy and pH on photocatalytic degradation of the dyes was investigated. It was observed that pH and the initial dyes concentration has a significant role in the dyes removal process. Using the optimum conditions (parameters), almost 90% degradation was achieved by nano ZnO in a short span of time. The efficiency achieved in this work using nano ZnO was much higher than micro ZnO catalyst and using conventional custom made setups. This is a first study of its kind where laser and nano ZnO particles have been employed for removal of dyes from wastewater.