Global NEST Journal

The identification of PM sources and their contribution to measured PM concentrations is crucial for the environmental policy making since the findings be able to conduce to the development of relevant legislation in order to achieve effective air quality manage. In this study, the sources of PM10 at three receptors with different characteristics, within the Western Macedonia (WM) in NW Greece, were investigated: S1 in the center of Kozani, a medium sized city located at the southern edge of the industrial axis of WM, where urban activities and traffic density occur. S2 in the city of Ptolemaida, a medium sized city located in the centre of industrial zone, and S3 in the village of Eratyra, a rural residential district outside of the industrial area. For this purpose the multivariate Positive Matrix Factorization (EPA PMF 5.0) receptor model was applied on elemental data. Specifically, PM10 samples, obtained by filtration during 1-year sampling campaign, were analyzed by ICP-MS instrument. Twenty five elements were detected at quantifiable concentrations in the investigated PM samples. For the particle samples obtained in areas within and proximal from mining and power station operations, a six-factor model gave source profiles that attributed to be vehicle exhaust, road dust, soil dust, coal combustion, oil combustion and biomass burning. Furthermore, at the background site, the major contributors were biomass burning, soil dust and oil burning while no distant transport from industrial axis was recorded.

Metallurgy and recovery of gold in electronic waste sometimes involve the reduction of tetrachloroaurate ion (AuCl4-) to elemental gold form. Currently, for the reduction of tetrachloroaurate ion, people use reducing agents such as hydroquinone and sodium borohydride. Photocatalysts of Fe3O4/SiO2/TiO2 nanoparticles were prepared and tested for the reduction of tetrachloroaurate ion under UV light illumination. The magnetite (Fe3O4) nanoparticle was first prepared by coprecipitation and sonication, followed by SiO2 and TiO2 coatings via the sol-gel process and calcination. The products were confirmed by XRD and TEM. The photocatalytic reduction of tetrachloroaurate ion was performed in a closed reactor equipped with a UV light source. The results indicated that Fe3O4/SiO2/TiO2 nanoparticles were successfully prepared, which retained good magnetic and photocatalytic properties. The photocatalytic reaction is best performed at a pH of 5 under UV irradiation for 2 h, which is capable of reducing 96% of the tetrachloroaurate present in the mixture. The co-presence of Ni2+ and Cu2+ ions in the solution leads to a decrease in yield due to competitive reduction and adsorption. The photocatalyst is recoverable by the use of a magnetic bar and may find application for gold recovery and metallurgy.

Samples of soil acquired from electrical and electronic waste (e-waste) dumpsite in Kansuwan gwari, Minna, Nigeria were utilized for the isolation of microorganisms utilized as a part of lead (Pb) biosorption studies. The soil specimen was cultured for Saccharomyces cerevisiae and Candida tropicalis. Box Behnken plan was utilized to advance the removal of lead by the organisms. The factors utilized as a part of the Box Behnken plan were temperature, pH and concentration of Pb. Saccharomyces cerevisiae was enhanced by the Box Behnken design, a temperature of 250C, pH of 6 and a lead of 2ppm concentration prompted a 70.8% lead removal. The investigation of variance for Candida tropicalis demonstrated that the reaction had a probability estimation of 0.851 for the regression. This likewise showed the model was not a solid match for the plan since the p-value (0.851) was more prominent than 0.05. S. cerevisiae gave a probability estimation of 0.029 for the regression, which demonstrated that the model was a solid match for the outline since the p-value was less than 0.05. More models may be connected to different fields in microbiology as it diminishes the ideal opportunity for protracted examinations and tends to limit the test to how successfully the outcomes can be accomplished. This study can be connected to the master plan of the effective pH, temperature and different parameters for the clean up of contamination in the environment.

To discriminate the specific response of ion toxicity versus osmotic stress on altering leaf solute contents, contributing of organic and/or inorganic components in osmotic adjustment and its reflection on plant performances under ionic and osmotic stresses, two cotton (Gossypium barbadense L.) cultivars, Giza 90 and Giza 83, were subjected to iso-osmotic concentration (–0.57 and –1.05 MPa) created by; NaCl, KCl and polyethylene glycol-6000. The three used osmotica altered seedling length, chlorophyll, leaf dry weight, relative water content, organic and inorganic solutes and proline. Contribution of organic solutes to osmotic adjustment tittered among the two cultivars, it was higher in PEG˃ KCl˃ NaCl in Giza 83, suggesting that the character of osmotic adjustment via salt attuned to high yield with moderate ion toxicity is effectively achieved by KCl than NaCl. At high-stress intensities, regardless to cultivar, the salt stress-induced nutritional imbalance, leaf chlorosis than osmotic stress that could be attributed to specific ion toxicity, not to osmotic stress of salt. In salt sensible cultivar only NaCl, among different osmotica, reduced leaf K+ content implying that avoidance of Na-induced K+ deficiency in leaf might stimulate salt tolerance in cotton. In our study, the capacity of plants to regulate their metabolic and physiological functions had superiority in water stress tolerance rather than osmotic adjustment.