A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon （ZVI/AC）, microwave discharge electrodeless lamp/sodium hypochlorite （MDEL/NaCIO） and th...A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon （ZVI/AC）, microwave discharge electrodeless lamp/sodium hypochlorite （MDEL/NaCIO） and the combination of ZVI/AC- MDEL/NaCIO was conducted. The preliminary results showed the two steps method of ZVI/AC-MDEL/NaCIO had much higher degradation efficiency than both single steps. The final color removal percentage was nearly up to 100% and the chemical oxygen demand reduction percentage was up to approximately 82%. The effects of operational parameters, including initial pH value of simulated wastewater, ZVI/AC ratio and particle size of ZVI were also investigated. In addition, from the discussion of synergistic effect between ZVI/AC and MEDL/NaCIO, we found that in the ZVI/AC-MEDL/NaCIO process, ZVI/AC could break the azo bond firstly and then MEDLfNaCIO degraded the aromatic amine products effectively. Reversing the order would reduce the degradation efficiency.展开更多
Reactive Red 195, which is an azoic anionic dye characterized by the presence of five sulfonic groups and one azoic group, is efficiently removed using chitosan. The increasing chitosan dose had a dramatic positive im...Reactive Red 195, which is an azoic anionic dye characterized by the presence of five sulfonic groups and one azoic group, is efficiently removed using chitosan. The increasing chitosan dose had a dramatic positive impact on the achieved color removal, there was approximately a linear relationship between chitosan dose and color removal of dye before color removal reach maximum. Also, the increase of dye concentration led to the increase of chitosan dosage in order to get the same color remova l.92 mg/L of chitosan dosage was sufficient to achieve complete remove of dye at initial concentration of dye at 200 mg/L. For the higher concentrations of dye, high dosages were necessary to reach complete color removal. On the other hand, the use of adsorption interferents（Fe^2＋ , Na^＋ , HCO3^- and others） can be interesting, addition of ions had effect on the color removal of Reactive Red 195. Comparing with blank, addition of chemical species approximately decreased the color removal except Na^＋ and combination of Fe^2＋ ＋ HCO3^- . However, comparing with Fe^2＋ alone and HCO3^- alone, combination of Fe^2＋ ＋ HCO3^- increased the color removal.展开更多
Textile wastewater shows great threats to the environment if not well pretreated before discharge. A promising technique, ozonation, was applied to remove the color in dye solutions containing C.I. Reactive Red 195 （...Textile wastewater shows great threats to the environment if not well pretreated before discharge. A promising technique, ozonation, was applied to remove the color in dye solutions containing C.I. Reactive Red 195 （RR195） in a semi-batch reactor. The decolorization of RRI95 by the ozone process followed pseudo-first-order kinetics. Several factors which influenced the efficiency of decolorization were studied and the reaction rate constant （k） obtained with different operational parameters was compared. Our results showed that RRI95 was more easily degraded in acidic than in alkaline conditions. The dyeing auxiliaries （sodium carbonate and sodium chloride） that acted as radical scavengers could enhance the decolorization process, and the ozonation time for total color removal lengthened if the initial dye concentration was higher. The analysis of the ozonation products was performed by liquid chromatography-tandem mass spectrometer and a possible degradation pathway was predicted according to the ozonation products and structure of RR195. Our results indicated that ozonation was effective in the color removal of dyes, but further treatment might be necessary since the ozonation products are high toxic.展开更多
基金supported by the Major Projects on Control and Rectification of Water Body Pollution (Water Special Project) (No.2009ZX07010-001,2008ZX07526-001)the National Basic Research Program (973) of China (No.2008CB418201)
文摘A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon （ZVI/AC）, microwave discharge electrodeless lamp/sodium hypochlorite （MDEL/NaCIO） and the combination of ZVI/AC- MDEL/NaCIO was conducted. The preliminary results showed the two steps method of ZVI/AC-MDEL/NaCIO had much higher degradation efficiency than both single steps. The final color removal percentage was nearly up to 100% and the chemical oxygen demand reduction percentage was up to approximately 82%. The effects of operational parameters, including initial pH value of simulated wastewater, ZVI/AC ratio and particle size of ZVI were also investigated. In addition, from the discussion of synergistic effect between ZVI/AC and MEDL/NaCIO, we found that in the ZVI/AC-MEDL/NaCIO process, ZVI/AC could break the azo bond firstly and then MEDLfNaCIO degraded the aromatic amine products effectively. Reversing the order would reduce the degradation efficiency.
基金The State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technologyin Zhejiang University of Technology
文摘Reactive Red 195, which is an azoic anionic dye characterized by the presence of five sulfonic groups and one azoic group, is efficiently removed using chitosan. The increasing chitosan dose had a dramatic positive impact on the achieved color removal, there was approximately a linear relationship between chitosan dose and color removal of dye before color removal reach maximum. Also, the increase of dye concentration led to the increase of chitosan dosage in order to get the same color remova l.92 mg/L of chitosan dosage was sufficient to achieve complete remove of dye at initial concentration of dye at 200 mg/L. For the higher concentrations of dye, high dosages were necessary to reach complete color removal. On the other hand, the use of adsorption interferents（Fe^2＋ , Na^＋ , HCO3^- and others） can be interesting, addition of ions had effect on the color removal of Reactive Red 195. Comparing with blank, addition of chemical species approximately decreased the color removal except Na^＋ and combination of Fe^2＋ ＋ HCO3^- . However, comparing with Fe^2＋ alone and HCO3^- alone, combination of Fe^2＋ ＋ HCO3^- increased the color removal.
文摘Textile wastewater shows great threats to the environment if not well pretreated before discharge. A promising technique, ozonation, was applied to remove the color in dye solutions containing C.I. Reactive Red 195 （RR195） in a semi-batch reactor. The decolorization of RRI95 by the ozone process followed pseudo-first-order kinetics. Several factors which influenced the efficiency of decolorization were studied and the reaction rate constant （k） obtained with different operational parameters was compared. Our results showed that RRI95 was more easily degraded in acidic than in alkaline conditions. The dyeing auxiliaries （sodium carbonate and sodium chloride） that acted as radical scavengers could enhance the decolorization process, and the ozonation time for total color removal lengthened if the initial dye concentration was higher. The analysis of the ozonation products was performed by liquid chromatography-tandem mass spectrometer and a possible degradation pathway was predicted according to the ozonation products and structure of RR195. Our results indicated that ozonation was effective in the color removal of dyes, but further treatment might be necessary since the ozonation products are high toxic.
