Çevre Bilimleri

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Browsing Çevre Bilimleri by Subject "Azo dyes."

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    A QSAR study on the mutagenic activity of azo dyes and aromatic amine derivatives
    (Thesis (M.S.)-Bogazici University. Institute of Environmental Sciences, 2019., 2019.) Küçükali, Müge.; Saçan, Melek Türker.
    In the present study, the mutagenic activity of diverse structure of azo dyes and aromatic amine derivatives on TA98 Salmonella typhimurium bacterial strain with S9 activation was used to generate a quantitative structure – activity relationship (QSAR) model. The descriptors required for the model development were obtained by SPARTAN (v.10), DRAGON (v.7.0) software packages. The selection of descriptors was carried out by the tools implemented in QSARINS (v.2.2.3) software. Many division trials were performed on the dataset as training and test sets which comprise the 80% and 20% of the whole set, respectively. 6 descriptors (CIC2, Chi_D/Dt, L/Bw, TDB09p, Mor28s and piPC08) constitute the final model. The applicability domain (AD) of the generated QSAR model was defined by both the ranges of response and descriptors. The predictive ability of the final model was tested using an external dataset consisting of currently used 33 anionic water soluble textile dyes (eight anthraquinone and 25 azo dyes) with no experimental mutagenicity data. The proposed QSAR model had 70% structural coverage for the external set chemicals. The mutagenic activities of 22 current textile dyes belonging anthraquinone and azo dyes fell within the applicability domain of the proposed QSAR model which means that they were well predicted by the model. The order of 6 anthraquinone dyes which are mainly used for cotton, fiber dyeing and leather shading with the most mutagenic activity is: Acid Blue 62>Acid Blue 40>Acid Blue 45>Acid Blue 80>Acid Blue 230>Acid Blue 344. The least mutagenic azo dye is Direct Orange 34 which is mainly used for cotton, silk, wool and their blended fabric dyeing and printing, also can be used for leather and paper shading.
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    Enhancement of azo dye decolarization by Dunaliella tertiolecta with conventional carbon sources
    (Thesis (M.S.)-Bogazici University. Institute of Environmental Sciences, 2006., 2006.) Akbaş, Mehtap Kanyılmaz.; Saçan, Melek Türker.
    In this study, the decolorization of Dye Bath (DB), and the three hydrolyzed dyes, namely Reactive Black 5 (RB-5), Reactive Orange 69 (RO-69) and Reactive Yellow 37 (RY-37) by marine microalgae Dunaliella tertiolecta, in a batch culture was investigated and the ability to utilize the azo dyes in the presence of co-substrates namely glucose and glycerol as an additional carbon and energy sources was discussed. Decolorization of dyes was determined by monitoring the decrease in the intensity of absorption at the maximum wavelength (lmax) of each of the dye solution. The color change and pH values of the culture media were monitored during the growth period of algae exposed to dyes in the presence and absence of glucose and glycerol. The individual and combined effects of DB, RB-5, RO-69 and RY-37 in the presence and absence of glucose and glycerol on the growth of Dunaliella tertiolecta were also examined. Algal growth was followed through optical density (OD750) measurements of the culture medium. Furthermore, algal growth was examined with different concentrations of glucose and glycerol. D. tertiolecta was found to be quite effective in the decolorization of all dyes. At low dilutions (30% and 60% (v/v)) of all DB, RB-5, RO-69 and all dilutions of RY-37 can be removed without co-substrate by the algae. However, addition of both concentrations of glucose and glycerol has some beneficial effects such as increasing the decolorization efficiency or decreasing decolorization period of all dyestuffs except RY-37. At concentrations beyond the IC25 values of dyes, decolorization achievement is decreasing due to the different structure and complexity of dyes. Considering the average 8-d IC25 and SC20 values expressed as % dilution (v/v), the order of toxicity was found as DB>RB- 5>RO-69>RY-37. Glucose and glycerol increased the stimulatory effect of all the tested chemicals on the growth of algae at a low concentration range, whereas the inhibitory effect at a high concentration range decreased. Glucose and glycerol did not affect the initial pH values and pH-changing trend of the medium containing dyestuffs, significantly.