in this study, oxidation of dye from colored wastewater by H2O2/ Multiwall Carbon Nanotubes solution assisted with UV radiation was investigated. Disperse Blue 56 was used as a model dye. Adsorption behavior of Disperse Blue 56 from aqueous solution onto Multiwall Carbon Nanotubes was investigated under various conditions such as initial pH value, dye concentration, H2O2 and Multiwall Carbon Nanotubes content. Maximum adsorption capacity for Disperse Blue 56 at pH 7.0, 5.0 and 3.0 was found to be 0.53, 0.56 and 0.97 mmol/g, respectively. Isotherm results demonstrated that the linear correlation coefficients and standard deviations of Nernest and Freundlich isotherms were specified and that the Freundlich isotherm best fitted the experimental results. The adsorption kinetics was more precisely denoted by a pseudo second-order model revealed by regression grades. Furthermore, it was shown that the UV/H2O2/ Multiwall Carbon Nanotubes process could be used as eco-friendly method to degrade dyes from colored wastewater.

An improved chemical regeneration of the granular activated carbon (GAC) exhausted by the color (pigments and pollutants) from citric acid fermentation solution (CAF) was investigated. In the experiments, improved means were adopted to advance the traditional chemical regenerating method and the adsorption capacity of the first time renewed GAC is 103% of original GAC. Using oxidant and surfactant in addition to just using NaOH solution can recover 10% more adsorption capacity of renewed GAC. The adding dosage of oxidant is good at 3% of exhausted GAC weight; that of surfactant is good at 0.1%. Hot water as cheap reagent was found to be much helpful to the regeneration efficiency. Comparing with steam regeneration high regeneration yield (>95%) of this method was an attractive economic factor. The result of this investigation can offer an advanced chemical regeneration method to regenerate exhausted GAC from citric acid refine industry.

In this study, degradation and decoloration of reactive and acid commercial dyes (C.I. Reactive Black 5 and C.I. Acid Red 151) in water under the irradiation with electron beams were investigated. Both dyes in aqueous solutions with the concentration of 100 ppm were irradiated at different doses of 1, 3, 6 and 9 kGy. The changes of the absorption spectra, degree of decoloration, pH, and chemical oxygen demand (COD) were analyzed. In addition to the influence of the absorbed dose the hydrogen peroxide additions on RB5 dye are discussed. The experimental results show that the reactive and acid dyes in aqueous solutions can be effectively degradiated by irradiation with the electron beam. The absorption bands for RB5 and AR151 decreased rapidly at 1kGy irradiation dose and disappeared almost completely at 9kGy. Also the degree of decoloration of RB5 solution at 1kGy dose and with the concentrations of H2O2 up to 5mmol/L was higher than 99.78%. Due to the production of organic and inorganic acidic anions the pH decreased during the irradiation.

Removing sugar color is one of the most important goals of raw sugar refineries. Also, color and ash have the most important effect on the quality of crystallized sugar. In order to produce high quality products, every year, a lot of equipment and operating costs and spend for the remove of the color and ash in every sugar mill and refinery. The quality of sugar depends on the quality of the sugar syrup that is produced from it, so the effective refine process, which has the ability to produce bright syrup with a low amount of color, is necessary in the sugar industry. In this research, Treatments of Brix in three level (40, 50 and 60), syrup Flow rate in three level (4, 6 and 8 ) and the Temperature in three level (40, 50 and 60 °, C) were considered and color, Invert, pH, ash and purity were measured according to ICUMSA methods and based on the efficacy of each treatments in decoloration and also according to the characteristics of the syrup, optimization was done by the surface response method. The model offered by response surface for the responses of color, pH, Invert sugar, and purity were significant and it was found that the use of ozone in important parameters in the sugar industry includes a reduction in color has a positive effect and on other parameters such as ash, pH, Invert Sugar, and purity have very little effect. The optimal treatment introduced by the model was temperature 43 °, C, flow rate 4. 2 and the Brix 54, and it was found that no significant effect between amount of specified by software and experimental samples(p>0. 05) and optimization points specifiedtruly.

Background and Objective: Methylene blue (MB) is one of the cationic dyes whose presence in textile industries wastewater can be hazardous for ecological systems as well as general health due to aromatic features.The present study aimed to investigate the effectiveness of electrocoagulation (EC) and electro-fenton (EF) processes at decoloration of MB dye from aqueous solutions using iron electrode.Materials and Methods: This research is a laboratory study carried out as pilot in library scale in the first half of 2014 in Environmental Health Engineering Research Center of Kerman Medical Sciences University. The reactor with general volume of 500 ml containing two Fe-Fe plate electrodes (15×2 cm) connected to a [direct current: (DC)] power supply was used for decoloration of MB dye. The effects of different factors such as contact time, dye concentration, Hydrogen Peroxide concentration (for EF process), used energy, electrolyte, optimal pH, and inter electrode distance were investigated. Data were analyzed using two-way ANOVA.Results: The average efficiency rate of removing MB through EC in optimal conditions (with primary dye concentration of 25 mg/L, pH=7, current density=50 mA, contact time=30 min, inter electrode distance=1 cm) was 93.3%±1.3%, and the removing efficiency rate of EF in optimal conditions (with primary hydrogen peroxide concentration of 100 mmol/L, the primary dye concentration=25 mg/L, pH=5, current density=0.05 A, contact time=30 min, inter electrode distance=1 cm) was obtained 78.9%±0.1% (p=0.003).Conclusion: The results showed that both EC and EF methods were effective in removal of MB dye from aqueous solutions; however, with optimization of effective operational factors, EC method could be more efficient.

Introduction: Textile wastewaters are heavily polluted with dyes and chemicals and have a broad range of pH, high COD concentration and suspended particles. In this study, the efficiency of color and turbidity removal from synthetic textile wastewaters were investigated by a combined process of coagulation/ flocculation and electron beam irradiation.Materials and Methods: The experiments have been done on model dye solution samples, which were prepared from ten dyes supplied from Yazd Baff factory. Aluminum sulphate was employed as coagulant. Then samples were irradiated by electron beam accelerator at different doses. Absorption spectra of the samples were measured using UV-Vis spectrophotometer. The pH and turbidity values of the solutions were measured by a pH meter and turbidimeter.Results: According to results, the degree of decoloration and turbidity removal of synthetic dye solutions increased when the alum concentration increased and reached 64% and 90% respectively at 112 ppm of alum. After irradiation, it is observed that absorbance decreased rapidly at 540 nm by increasing the radiation dose because of macromolecules degradation and then it decreased slowly to a degree of decoloration of 95% at 3 kGy. The level of pH decreased by irradiation and then changed very slowly or remained constant with increasing irradiation dose.Conclusion: The results indicate that a combination of coagulation/ flocculation and irradiation is so effective for turbidity removal and decoloration. Coagulation process eliminates suspended particles from disperse dyes effectively, while destruction of soluble dye molecules happens by irradiation, which considerably increases decoloration efficiency.

Background and Objective: One of the most important problems of modern society is water pollution. Among these pollutants are organic dyes pollutant in industrial factories effluent, which the removal them is very important. The purpose of this study is to provide a solution to eliminate the methyl orange organic dye in industrial factories wastewater by Spark plasma. Material and Methodology: In this study, the decolorization and degradation of methyl orange solution were investigated by electrical discharge plasma method at the water-gas interface. The electrical discharge device used in the present work is spark type plasma with needle-plate electrode structure, with effective voltage 1-12 KV and constant frequency 13 KHz. Findings: The results show that decolorization and degradation of methyl orange dye solution begins at the air-gas-air interface, which can be due to ultraviolet radiation and production of OH radical and highly reactive species H2O2 at the air-gas interface. The effects of the discharge device parameters such as the applied voltage, electrode gap, treatment time and also chemical effects of the solution such as the concentration of the dye have a significant role on decolorization. The results showed that with increasing voltage and increasing treatment time, the amount of decolorization increases, and also by keep the electrical power of the device constant, the amount of decolorization decreases with increasing concentration. Selecting a distance of 2 cm between the electrodes, the highest amounts of decolorization in solution have been observed. Discussion and Conclusion: In this reactor, the initial pH has no significant effect on decolorization efficiency. Also, the highest decolorization rate of 99. 8% occurred at a concentration of 30 ppm, effective voltage 10 KV, electrode gap of 2 cm, initial pH = 3 and in 30 minutes treatment time.