Polyacrylonitrile (PAN) hollow fiber membranes were manufactured through the dry-jet wet spinning. Considering importance effect of structure of hollow fiber to separation performance, spinning parameters such as coagulants composition were changed to achieve suitable hollow fiber membranes. Water with different amount of glycerin was used as the bore liquid and coagulation bath. The effects of the glycerin concentration on the hollow fiber permeation and separation performance were investigated. Direct red 80 was used to measure the separation performance of hollow fiber module. Field emission scanning electron microscope (FE-SEM) was used to analyze the structure of the hollow fibers. The results proved that permeation is increased by adding glycerin to external and internal coagulation bath. In addition, hollow fibers spun in lower glycerin value would indicate lower hydraulic permeability, higher separation and higher tensile strength.

Chemical and biological treatment of dye-containing effluents is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and recovery problems, researchers are investigating to find available low-cost materials with high adsorption. In this study, bagasse was used for adsorption of Remzol Black B dye and its capability was examined. Variables were concentration, temperature, pH and contact time, and the degree of adsorption was examined in different situations. Then, adsorption isotherm according to Langmuir and Freundlich models were developed. The results showed that the adsorption efficiency depends on pH of solution and to a lower degree on temperature of the solution. Maximum adsorption of Remzol Black B dye by bagasse occurred in the first 15 minutes of contact. The study of adsorption isotherm showed that both models are suitable for description of adsorption of Remzol Black B dye by bagasse. Maximum adsorption of Remzol Black B dye by bagasse was calculated as 7. 51 mg/g. Results of this study showed that bagasse could be used as a low-cost bio adsorbent for the adsorption of Remzol Black B from aqueous solution.

Introduction: Nowadays, the industrial effluents contain mineral and organic hazardous materials such as phenols, heavy metals, and dyes, which are carcinogenic and poisonous compounds even at low concentrations. An increase in such components especially dyestuffs in the environment makes the remediation of these pollutants valuable. Toluidine Red is a pigment containing azo groups, which is invasively used in different industries. There are several chemical, physical, biological, optical, and combinational methods for different pollutant removal from the environment. In recent years, the bioremediation technique has been considerably developed as an effective method in pollutant removal. Therefore, the goal of this study was to optimize the Toluidine Red removal from the synthetic dyes wastewater by Halomonas strain D2 in static culture conditions. In this survey, optimization and variables’ effectiveness study was performed by the response surface methodology (RSM). Material and methods: In this research, the effectiveness status of variables and optimum conditions were studied by the statistical approach of Design Expert V. 7 software. Biodegradation of dye was investigated by 30 experiments according to the Central Composite Design (CCD) and RSM. According to previous related research performed by one factor at time (OFAT), the effects of four variables of dye concentration, NaCl salt concentration, pH, and temperature on bioremediation at 10-30 ppm, 2-10 %, 5. 5-9. 5 and 20-40 ͦ C, respectively, were studied. Bioremediation experiments in the aqueous phase of the synthetic model effluent have been performed in shake flask scale and static culture condition in an incubator for 10 days. Then the analysis of the resulted data was performed by analysis of variance. Results and discussion: According to the results and analysis of variance, salt concentration and temperature are the most significantly effective variables on bioremediation in the studied range while pH and dye concentration were probably less significant. Furthermore, the interactive effect of dye concentration and pH, salt concentration and pH as well as salt conEnvironmental centration and temperature were in a 95% effectiveness possibility limit. On the other hand, the maximum dye removal was observed on the 10th day of the experiment with 62. 4%. The optimum condition for bioremediation was observed at a pH of 8. 5, the temperature of 35 ͦ C, and salt and dye concentrations of 4% and 16. 8 ppm, respectively. By RSM, a correlation of second order for dye removal percentage after 10 days was presented with R2 equal to 0. 95. The average error of the proposed correlation and real experimental data was about 9. 9%. Conclusion: The second-order correlation proposed in this paper can effectively predict the different operational condition effects on removal of Toluidine Red by Halomonas strain D2 that is a useful bacterium in dye biodegradation. Comparing this survey with our previous study, which was about decolorization by Gb strain, shows that the optimum condition is different for each strain type. On the other hand, D2 strain performance was higher in the basic condition in comparison with strain Gb, however, in acidic conditions, the Gb strain’ s performance was better.

The adsorption of an anionic dye (ARS) on raw typha grass (RAW-TG) was studied using an equilibrium batch approach. To test their impact on the ARS removal, the operational parameters of contact time (15 minutes), starting dye concentration (120 mg/L), adsorbent dosage (0.02 g), and pH (8) were tuned. Among the physical properties that were looked at were the RAW-TG's bulk density (0.397 g/cm3), pore volume (1.253 cm3), and moisture content (17.80 %). To better characterize the adsorbent, it was further studied using scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and point of zero charges (PZC) techniques. To numerically model equilibrium data, the Langmuir, Freundlich, Temkin, and Dubining Radushkevich (D-R) models were utilized. Pseudo-first-order, pseudo-second-order, Elovich, and Intraparticle diffusion models were used to calculate the adsorption kinetics. Using the Van't Hoff plot, the thermodynamic parameters affecting the adsorption process were calculated. The data were presented most effectively by a pseudo-second-order model with a maximum adsorption capacity of 46.511 mg/g, and Freundlich's interpretation of the adsorption isotherm was significantly more favorable than that of the other models examined. According to the thermodynamic characteristics, the process was viable and spontaneous, with adsorption values of ΔG (-6.737 to -8.271 kJ/mol), ΔH (16.616 kJ/mol), and ΔS (16.616 J/molK, respectively. The findings of this investigation demonstrate that RAW-TG is an efficient, reasonably priced, and environmentally friendly adsorbent for the removal of ARS dye from aqueous solutions.

Introduction. Color is considered as one of the major water resource  pollutants and other parts of the environment. In tannery industries the application of trivalent chromium salts in tanning of leather produces a hazardous color which being disposed directly to environment and it is likely to change to hazardous hexavalent form in the oxidation conditions of the receiving environments. During the last few years, studies have shown the potential of fungi in removing the color of waste waters in appropriate conditions. The aim of this research was to study decolonization of tanning house effluent by Aspergillums niger in tannery industries for biological removal of chromium.Materials and Methods. The first, quality of tanning house effluent was studied. After adjusting of carbon to nitrogen ration in the effluent, A. nigar was inoculated in the different size into the effluent with different dilutions. The samples for 24 h. put in the shaker incubator. Then, the absorbance rate in the wave length of 565 nm and biomass growth was estimated.Results. In this research Aspergillums niger was selected as the species of fungi for removing color from tanning house effluent. Results showed that Aspergillums niger is able to grow effectively in the tanning house effluent with dillution percentages of 10% and 20% (or chromium concentration 122.5 and 245 mg/l), with C/N ratio of 10 and pH=3; and can reduce the color, 94.5% and 93.4%, respectively. According to the experiments in this study, the best size of inoculums was determined as 10 ml. The percentage of decolonization was increased due to the increase of dry weight of fungal mass to the concentration of chromium (1.7-23.7 mg dry weight of mass/mg trivalent chromium). The highest chromium removal percentage, 94.5%, was obtained  in the 23.7 mg/mg ratio. The meaningful relationship of these parameters is confirmed according to the multiple regression coefficient of 0.8836.Conclusion. This study showed that Aspergillums niger can grow in tanning effluent and remove about 95% of color caused by trivalent chromium. Therefore, can be removed efficiently during the decolonization process.

The rate and efficiency of decolorization of dyes like Blue CA, Black B133, and Corazol Violet SR were tested to evaluate white rot fungal strains. Trametes hirsute and Pleurotus florida showed the greatest extent of decolorization on nutrient salt media. Maximum decolorization of 200 mg/l of Blue 133 was obtained by 4 days old incubated Pleurotus florida followed by Trametes hirsuta after 6 days. An attempt was made to improve the decolorization activity of both organisms with different concentrations of glucose 1 and 2% (w/v). The decolorization activity may be due to the laccase enzyme of white rot fungi. The production of this enzyme was estimated using solid state fermentation with rice bran as a substrate. It was found that P. florida exhibited 0.175 U/ml of laccase activity followed 0.126U/ml by T. hirsute, respectively. Decolourization was found to be more effective with P. florida in the presence of 2% (w/v) glucose. Crude extract containing the laccase enzyme was isolated and confirmed by SDS PAGE.