Synthetic dyes are among the substances that pollute the ecosystems such as the soil, surface water, and underground water, and affect living organisms when industrial effluents are released in the environment. The most common synthetic dyes are Azo dyes, among which are the reactive dyes that can cause a lot of problems due to their high solubility in water and low degradability.In this study, one gram negative bacilli (Shewanella putrefaciens) with a high capacity in decolorization of azoic dyes, especially reactive black 5, is isolated from among 15 microbial strains in Tehran textile effluents.The results of the study showed that, in the presence of external energy and carbon source, this strain could decolorize the dye in a shorter period of time. An 18-20h pure culture of Shewanella putrefaciens decolorized more than 80% of the dye during 12 hours under aerobic conditions in broth and the figure reached 100% after 24 hours. Decolorization in Saline Basal Medium during 48 h was 85%, when the dye was regarded as the sole source of carbon and energy. The conditions for the gram negative bacilli (Shewanella putrefaciens) that had the best effect on decolorization were as follows: a temperature of 30°C, the pH of 6-6.5, 150 rpm shaker speed, and 200 ppm (mg/l) concentration of dye. Decolorization took place better in the presence of yeast extract as nitrogen source and sucrose as carbon source. Moreover, the culture showed a better decolorization activity in the logarithmic phase of growth.Since the Shewanella putrefaciens do its decolorization activity in a short period of time even in an autotrophic pathway, it is thus this strain that can have a valuable role in biodegradation of dye compounds in textile effluents.

Background and Objective: Heavy metals and dyes are released into the environment by industrial activities and technological development more than natural. Because of their toxicity, they have anomalous effects on the environment and on the health of organisms, especially humans. Method: In this research, two methods of advanced oxidation and biological adsorption were combined in a single reactor and the pollutants were introduced into the reactor and the percentages of their removal were investigated. . The UV / H2O2 process was used to remove the RBB dye and to remove the manganese ion from a biological adsorbent fixed in sodium alginate. After performing these two processes in the batch system and considering the optimum conditions in the unit reactor, these two processes were combined and the granules were poured into a polyethylene filter and placed inside the reactor embedded in the center of the UV lamp. Findings: According to the results of TOC and COD, it was found that in the case of only UV / H2O2 process, the percent removal of TOC and COD were 35% and 79. 5%, respectively, but in the combined condition, the percentage of TOC reduction was 56% and COD It reaches 90. 22%. Discussion and Conclusion: The results have shown that the removal efficiency both in terms of decolorization and mineralization is negligible when UV, H2O2 or biosorbent are used alone. Among combining AOP with-biological process schemes tested, we found that the UV/H2O2/biosorbent process was the most effective in reducing the COD, color and TOC of decolorization

Bearing organic and inorganic pollutants, colored wastewater are an important source of environmental pollution. Removal dyes from dyestuff can be accomplished by various methods such as coagulationflocculation, Fenton regent, ozonation and so on. This work investigated metallic iron as an efficient and inexpensive material for treatment of colored wastewater. Parameters such as pH (3, 5, 7, 9 and 11), contact time (15, 30, 45, 60, 75, 90, 105 and 120 min), iron powder concentration (0.5, 1, 1.5 and 2 g/L) and initial dye concentration (25, 50, 75 and 100 mg/L) were studied. In addition, experimental data were fitted on pseudo- first order, pseudo-second order and modified pseudo-first order kinetic models. Result showed that dye removal was increased by increasing iron mass and contact time. While decreased by increasing pH of solution. Increasing initial dye concentration of AO7, has increased removal efficiency, while it was decreased by increasing initial dye concentration of RB5. In addition, results showed that pseudo-first order model best describe removal of AO7 (r2> 0.9708) and RB5 (r2>0.9776) by metallic iron. We concluded that metallic iron can be used as an effective an inexpensive matter for treatment of dyestuff waste.

This research reports on the examination of enzymatic decolorization. Decolorization of Reactive Black 5 using fungal peroxidase obtained from Coprinus Cinereus was studied in a stirred tank reactor. Effect of several parameters including hydrogen peroxide concentration, pH, dye concentration and enzyme activity on the decolorization of Reactive Black 5 was investigated. Dye decolorization efficiency of 67% was achieved under continuous feeding of dye solution and stepwise addition of hydrogen peroxide and peroxidase enzyme. Under this condition, pH value, dye and hydrogen peroxide concentrations were 8.0, 40 ppm and 96.1 mM, respectively. J. Color Sci. Tech. 5(2011), 11-20 © Institute for Color Science and Technology.

Dyes in the textile industry are the most significant source of pollutants, which cause damaging effects to people’ s health. Reactive black 5 (RD5) is an anionic color that is currently used in the textile industry. This study is designed to provide the strategies to synthesize and characterize the new family of functionalized magnetite nanoparticles via a chemical co-precipitation method with polyaniline modification groups on the surface. The effect of various parameters including pH, the initial concentration of RD5, the mass of adsorbent, contact time, temperature and ionic strength has been studied. Under optimal conditions, 10 ml of RD5 solution with a concentration of 30 mg l-1, 20 mg of adsorbent, pH of 7 and contact time of 10 min, the color was completely removed. The results also showed that adsorption of RD5 followed Langmuir isotherm (R2 = 0. 998) and the maximum RD5 adsorption capacity was 63. 69 mg g-1. The results of kinetic studies also showed that the RD5 removal followed the pseudo-second-order equation with the correlation coefficient of R2 = 0. 9984. The Δ G° was negative at all temperatures which shows that the adsorption process was spontaneous. Conforming to our results, adsorption process by designed magnetic nano-adsorbent is an efficient and affordable method for eliminating RD5 from the textile industry.