Sparse vegetation gives rise to increased overland water flow، soil erosion، Azo as a member of chromo-gen group has different efficiency in different industries such as mutation potential and carcinogenesis. Some kinds of chromo-gen are known in primary studies. Azo ch More
Sparse vegetation gives rise to increased overland water flow، soil erosion، Azo as a member of chromo-gen group has different efficiency in different industries such as mutation potential and carcinogenesis. Some kinds of chromo-gen are known in primary studies. Azo chromo-gen can cause undesirable color to water and also these colors have mutation and carcinogenesis potential in human and can produce poisonous side product in environmental water. The aim of this investigation is usage of iron، element to subject an effective method to remove azo dye acid yellow 36 of water solution. This experiment fulfills in the scale of laboratory. In this experiment synthetic solution made from color and efficiency of iron powder is considered in removing the yellow 36 acid color of water solution and effects of different parameters during the contact time. Effect of iron powder is considered in efficiency of removal by iron powder. Results of experiments show that PH solution is more effective in access to more removal. From the results of the experiment it can be concluded that the time of contact of Iron in the acidy solution as an important factor through access to more color is more effective. Increasing the contact time of iron powder in the solution، decreases the time of discoloration. Results of experiments show that pH have more important role on efficient color removing and Slight pH can be more efficient to remove the color. Increasing pH from 3 to 11 with iron powder 3.33 g/l and contact time of 100 minute، removal time is decreased from about 94.84% to 16.94%. This method is recommended to remove Azo dyes from environmental water as it is simple and efficient.
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Azo dyes are an important group of indicator that are used as pH sensors and can also be used in the structure of new sensors. In this research, a theoretical study has been conducted on the role of physical factors on the behavior of azo-halochromic dyes. The azo dyes More
Azo dyes are an important group of indicator that are used as pH sensors and can also be used in the structure of new sensors. In this research, a theoretical study has been conducted on the role of physical factors on the behavior of azo-halochromic dyes. The azo dyes studied in this paper are methyl red and methyl orange.The values obtained for the totomeric equilibrium constant show that the azo form of these indicators is more stable than their hydrazone form. Therefore, in this paper, only the relationship between acid-base equiblirum of azo form indicators is investigated. Also, the range of color change of pH indicators and the effect of physical factors on acid-base equiblirum of indicators will be examined. Studies show that increasing the temperature reduces the pH range of the color change of the indicators but the effect of pressure will decrease with increasing pressure, and the type of indicator will not affect this result.Studies also show that increasing polarity of the solvent and the use of isotopes of atoms will decrease the pH range of color change of the indicators. The method used in this research can be help the development of pH-sensitive sensors.
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In this research, porous graphitic silicon carbide (g-SiC) doped with nitrogen was synthesized as a metal-free photocatalyst by using silica foam as a silicon source and gelatin as a carbon source. The photocatalytic property of this compound was evaluated in the photoc More
In this research, porous graphitic silicon carbide (g-SiC) doped with nitrogen was synthesized as a metal-free photocatalyst by using silica foam as a silicon source and gelatin as a carbon source. The photocatalytic property of this compound was evaluated in the photocatalytic removal of azo dyes and gram positive and negative bacteria in visible light. The g-SiC showed a very high potential to remove organic pollutants (99 % in 10 minutes) compared to commercial SiC (8 % in 10 minutes). This enhancement in photocatalytic performance is related to the graphenic structure of this compound, which increases electron transfers and reduces the rate of recombination. Also, the oxygen molecules which dissolved in water can adsorbed on positive charged Si atoms in g-SiC structure and produce oxygenated radicals. These radicals can accelerate photocatalytic reactions as an active species. On the other hand, the use of silica foam increases the surface area, and with the nitrogen doping from the gelatin source, more structural defects, higher absorption, and a smaller band gap are created in the structure, which increases the photocatalytic activity. The obtained results show that this compound can remove azo dyes up to 100% and bacteria up to 80%.
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