الفهرس 
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Abstract
accumulation of dyestuff and dye effluent causes not only environmental degradation, but also medicinal and cosmetic problems. Azo dyes are the most commonly used synthetic dyes, accounting for about 70% of all textile dyestuff produced. They are simple to synthesize, inexpensive, stable, and can be used to colour a variety of things (textiles, leather, plastic, and food). They also allow for a wide range of hues and tints. They have one or more azo groups in their molecule. Textile industries face a particularly serious problem because they are major dye consumers and are responsible for discharging large amounts of highly coloured waste water effluents into nearby land and rivers without treatment, resulting in a variety of negative effects on aquatic ecosystems and human life. Concerns about the harmful effects of dye effluents have grown across the world, highlighting the necessity to create a dependable remediation technique to end the problem. Synthetic dye wastewaters have been treated using a variety of physical and chemical techniques. The majority of these techniques have severe drawbacks, such as high costs, low efficiency, limited flexibility, and the generation of secondary pollutants (sludge), among others. Bioremediation using different organisms such as bacteria, fungi, actinomycetes, yeast, algae, and plants on the other hand, it is a costeffective, efficient, ecologically friendly, and cost-effective process for removing colours from industrial wastewaters. In this study a number of lab-scale experiments on decolorization of azo dye solutions employing pure monospecific and mixed algal cultures have been undertaken. Algae can be a suitable option for large-scale wastewater treatment, either to replace or supplement existing treatment methods upon using pure cultures of biomass against a single pollutant; algal decolorization has been thoroughly investigated under the effect of controlled environmental conditions. Because of its large surface area and excellent binding ability, algae biomass has the highest bio sorption efficiency and electrostatic force of desire for contaminants in wastewater. Several studies have demonstrated that the algal surface adsorbs metabolites of contaminants present in wastewater. The presence of hetero polysaccharide and lipid compounds on the cell wall of algae comprises numerous functional groups such as amino, carboxyl, hydroxyl, and phosphate groups, which are responsible for the dyes’ high attraction to the cell wall. Algal cell surface functional groups are responsible for decolorization by attracting dye pollutants from the environment. Algae’s bio sorption ability is mostly influenced by their cell walls. Techniques such as immobilization of algae would improve adaptability, allow for easier cell collection, and increase the biomass’s reusability, lowering the total cost. Brown algae adsorption relies heavily on alginate by interacting with pollutant ions. Metal is, in general ions such as K+, Na+, Ca2+, and Mg2+ are acquired from seawater, which is accessible on the algal biomass linked to the functional groups of acids. Furthermore, the approach of coimmobilizing algae with other cooperating microorganisms would increase the decolorization rate even further. Temperature, pH, agitation, and dye concentration are also tested and monitored to improve bio decolorization efficiency. Furthermore, consortia of various types of microbiological strains, such as algae and cyanobacteria have been also used on the degradation efficiency of azo dyes that is helpful to the environment. After analyzing the physiochemical properties of the two dyes, the degraded metabolites were investigated using FTIR and UV–visible spectroscopy the influence of environmental factors (pH, different temperatures, culture conditions, different medium conditions, nitrogen, phosphorus, and vitamins) on the rate of decolorization by an immobilized microbial consortium was studied. FT-IR and GC-Ms analysis for azo dyes after and before treatment with Immobilization of Chlorococcum sp., and Chlorococcum sp. mixed with Scenedesmus obliquus were detected. The most important results are summarized as the following: 1) The highest removal of Reactive Orange 122 98.54 ± 0.006 was detected with Oscillatoria sp. mixed with S. obliquus and 98.40 ± 0.010 of Oscillatoria sp. at 20 ppm in the 7th day of incubation. The maximum decolorization of Reactive Red 194 was 97.58± 0.003 with Oscillatoria sp. mixed with S. obliquus and 91.53 ± 0.010 using Oscillatoria sp. at 20 ppm after 7 days of incubation. 2) The highest percentage of Reactive Orange 122 uptake was 79.61±0.01at pH 11 and the lowest was 56.31±0.01 at pH 5. At pH 9, Reactive Red 194 recorded maximum percentage uptake (81.36±0.02) and minimum (78.21±0.03) by Oscillatoria sp with Scenedesmus obliquus at 20 ppm in the 7 th day of incubation at pH 7. 3) The highest values of degradation of the azo dyes Reactive Orange 122 and Reactive Red 194 by Oscillatoria sp. mixed with S. obliquus were 83.98±0.01 and 87.41±0.01 after the fifth day of incubation, respectively, at 250C. At 60 0C, the results recorded the lowest values of removal of Reactive Orange 122 and Reactive Red 194 (21.36±0.02 and 57.63±0.01) by Oscillatoria sp. mixed with S. obliquus was after five days of incubation, respectively. 4) The best results for removal of Reactive Orange 122 and Reactive Red 194 by Oscillatoria sp. mixed with S. obliquus were 93.69± 0.002 and 87.65±0.014, respectively at light conditions after the fifth day of incubation. While the minimum percentage of degradation activity for both Reactive dyes were 82.52± 0.012 and 85.47±0.019 at dark condition with Reactive Orange 122 and Reactive Red 194, respectively after the fifth day of incubation. 5) After seven days of incubation, the results showed that the highest decolorization of Reactive Orange 122 by Oscillatoria sp mixed with Scenedesmus obliquus were 90.78±0.01 upen culturing in BG11 and Allen media. In BG11 and Allen media the degradation activity recorded 94.92±0.01 and 93.46±0.01, respectively, for Reactive Red 194. 6) The best removal of Reactive Orange 122 by Oscillatoria sp. mixed with S. obliquus recorded 92.72± 0.01 at 20.2 g l-1 KNO3 followed by 10.6, 10.1, 5.05, and 2.525 g l-1 KNO3, respectively after Five days of incubation. 7) The greatest decolorization activity of Reactive Orange 122 treated with Oscillatoria sp. mixed with S. obliquus was 84.47± 0.011 at 0.23 g l-1 of Na2HPO4.2H2O, on the third day, and increased up to 91.26± 0.01on the fifth day. After the third day of incubation with Oscillatoria sp. mixed with S. obliquus in Reactive Red 194, the greatest decolorization was 80.63±0.031at 0.45 g l-1 of Na2HPO4.2H2O that increased to 79.90±0.035 after the fifth day. 8) The highest degradation activity of Reactive Orange 122 in culture of Oscillatoria sp. mixed with S. obliquus was 79.13± 0.011 at 6% of thiamine. For Reactive Red 194, the highest degradation activity at 8% thiamine was 85.23±0.026 after the fifth day of incubation. 9) The highest percentage of Reactive Orange 122 uptake was 77.18± 0.01at 6% of ascorbic acid by Oscillatoria sp. mixed with S. obliquus after the fifth day of incubation. In Reactive Red 194, the highest degradation activity was 84.02±0.017 at 6% or 8% of ascorbic acid. 10) The FTIR spectrum of algae after dyes absorption were represented by some peaks that turned or disappeared, and some new peaks arised after absorbing dyes. 11) The highest yield (100 %) was obtained at pH 11 for both dyes with immobilizing Chlorococcum sp. and Chlorococcum sp. mixed with S. obliquus. 12) The highest value of Reactive Orange 122 and Reactive Red 194 uptake yield were achieved by the immobilized Chlorococcum sp. and Chlorococcum sp. mixed with S. obliquus 89.52±0.02 and 91.28±0.01, respectively at 250C and after five days of incubation. 13) Immobilized Chlorococcum sp. and Chlorococcum sp. mixed with S. obliquus are recorded maximum degradation activity 98.39±0.01 and 100±0 for Reactive Orange 122 and Reactive Red 194, respectively at aeration condition. 14) BG11 medium supported the highest percentage of degradation for both Reactive dyes after treatment with the immobilized Chlorococcum sp. and Chlorococcum sp. mixed with S. obliquus. The degradation activity for Reactive Orange 122 and Reactive Red 194 were 99.19±0.003 and 100±0, respectively in BG11 medium after five days of incubation. 15) For Reactive Red 194, the highest decolorization by immobilize Chlorococcum sp. mixed with S. obliquus at 10.6 g L-1 KNO3 was 72.15±0.01 after the third day and then increased to 96.13±0.01 after the fifth day, followed by 2.525 g L-1 KNO3 which supported removal percentage of 68.52±0.01 on the third day and increased up to 87.41±0.01 after five days of incubation. 16) In Reactive Orange 122, the best percentage of removal was 80.38±0.004 at 0.89 g L-1 Na2HPO4.2H2O after the third day of incubation. Then the percentage of decolorization activity decreased to 76.61±0.02 after the fifth day of incubation. 17) The best degradation activity of Reactive Orange 122 in cultures containing immobilizing Chlorococcum sp. was 99.46±0.002 at 10% of thiamine after the fifth day of incubation. 18) The optimal percentage of decolorization at 6% ascorbic acid was 100±0% after the fifth days of incubation. 19) FT-IR analysis of decolorized samples showed different peaks that represent different functional groups present in the compound. Infrared of biomass of immobilization of Chlorococcum sp and Chlorococcum sp. mixed with Scenedesmus obliquus before and after dyes treatment showed reduction in azo bond within the range of 1654 – 1542 cm-1. 20) The impact of immobilizing Chlorococcum sp. on Reactive Orange 122 before and after treatment was examined using gas chromatography-mass spectrometry (GC-Ms). When immobilized Chlorococcum sp. and Chlorococcum sp. mixed with S. obliquus and mixed with Reactive Orange 122 dye under the effect of pH11, the only two components present were Dodecane, 1-fluoro, and Cyclotetrasiloxane, octamethyl. In conclusion, these results proove that the one of the most promising adsorbents are algae and cyanobacteria because of their abundance, low cost, large specific surface area, and chemical and mechanical stability. The importance of diverse physico-chemical conditions for dye removal include pH, different temperatures, culture conditions, different media, nitrogen, phosphorus, and vitamins. As a result, these parameters must be considered when comparing the adsorption capacities of various algal adsorbents. After a brief incubation time, the immobilized microbial consortium is able to efficiently decolorize high concentrations of azo dyes. In all treatments, the immobilized cells were more effective in decolorization of azo dyes than free biomasses.