Optimization of operational parameters for decolorization and degradation of c l reactive blue 29 by ozone

Because conventional wastewater treatment of effluent containing anthraquinone dye causes notable environmental problems, it is important to find effective alternative methods for dye removal. This study evaluated the efficacy of ozonation for dye removal and Chemical Oxygen Demand reduction and identified optimal operational conditions for parameters such as pH, contact time and concentration of C.I. Reactive Blue 29 dye in a semi-batch reactor. Values of pH between 3 and 11 and contact times between 15 and 120 minutes were investigated. Dye concentrations were based on the American Dye Manufacture Institute standards and ranged from 1000 to 5000. Although results showed that Chemical Oxygen Demand removal by ozone alone was not very efficient [58%], ozonation proved to be an efficient method for decolorizing Reactive Blue 29 [96%]. pH was found to significantly influence the effectiveness of Chemical Oxygen Demand removal, and optimal pH conditions [95% confidence interval] were between 9 and 11. For decolorization, pH adjustment was not necessary. Degradation and decolorization of dye were found to be strongly influenced by the contact time, optimal conditions [95% confidence interval] for degradation and decolorization were 60 and 30 minutes, respectively. The optimal dye concentration was 1000 American Dye Manufacture Institute

[Comparison of efficiency of photochemical and sonochemical processes combined with hydrogen peroxide in removal of direct blue 71 [DB71] from aqueous solution: a kinetic study]

One of the important sources of environmental pollution existing in different industrial wastewater, including loom wastewater are dyes which are harmful for human health and environment. The purpose of this study was to investigate the efficiency of photochemical and sonochemical processes combined with hydrogen peroxide in removal of DB71 from aqueous solution. This study was experimental - laboratory study. At first, a reactor was designed and made. Then, optimum pH was determined which was 7 for photochemical and 3 for sonochemical process in constant condition. The effects of initial concentration of hydrogen peroxide, DB71 and contact time were studied at the constant optimum pH. Then data were interpreted and analyzed by use of Excel software and regression coefficient. The results of this study showed that with increased initial concentration of DB71, its removal decreased. But removal efficiency of DB71 increased by increasing contact time and initial concentration of hydrogen peroxide. In addition, kinetic parameters were obtained by application of first-order [Langmuir-Hinshelwood] equations. The results showed that UV/ H[2] O[2] and US/ H[2]O[2] processes can be effective in the removal of DB71 from aqueous solutions. Considering dye removal efficiency and availability, photochemical process combined with hydrogen peroxide can be recommended as a fast effective method for removal of dyes from aqueous solutions

[Comparison of photolysis and sonolysis processes for degradation of reactive red 198]

Carcinogenic and mutagenic potential of some azo dyes as a category of common dyes in different types of industries has been reported. The degradation of one commercially available dyestuff [C.I. Reactive Red 198 [RR 198]] by means of ultraviolet radiation [UV], ultrasonic irradiation [US], UV/H[2]O[2] and US/H[2]O[2] processes was investigated. Photolysis process was accomplished in a laboratory-scale batch photoreactor equipped with a 55W immersed-type low-pressure mercury vapour lamp [UVC] and sonication in a sonoreactor with low frequency [42 kHz] plate type transducer at 170W of acoustic power with emphasis on the effect of various parameters on decolouration and degradation efficiency. Initial results showed that, color removal efficiencies by US and US/H[2]O[2] processes were negligible. Almost complete disappearance of RR 198 [20 mg/L] in UV/H[2]O[2] process was possible to achieve after 10 min of irradiation. It is found that lower pH and lower concentration of dye favor the dye degradation. Hence any increase in initial dye concentration results in decreased decolouration rates. Also, the experimental results indicated that the kinetics of sono-oxidation and photo-oxidation processes fit well by pseudo-first order kinetics and first order reaction kinetics, respectively. It is concluded that UV/H[2]O[2] reaction was more effective than other reactions in bleaching and the reaction rate was sensitive to the operational parameters and increased with increasing H[2]O[2] concentration up to 15 mM

[Investigation of iron powder, hydrogen peroxide and iron hydrogen peroxide for removal of acid yellow powder 36 dye from aqueous solutions]

A great part of organic compounds cause more pollution in natural waters meet, are chemical dye material. Azo dyes have more usage in different industries. Azo dyes not only give undesirable dye to the water but also have mutation potential and carcinogenesis effects in human and cause the production of toxic substances in water environments. The purpose of this study is investigation of iron powder, hydrogen peroxide and iron powder-hydrogen peroxide processes in removal of acid yellow 36 dye from aqueous solutions. This study was conducted in laboratory scale. At this experiment synthetic solution was made from acid yellow 36 dye, and the removal of acid yellow 36 dye was studied by iron powder, hydrogen peroxide and iron powder-hydrogen peroxide processes .Also effect of dye concentration, pH solution, hydrogen peroxide concentration, iron powder concentration and the time of contact on decolorization, were evaluated. The results showed that iron powder-hydrogen peroxide process, compared to two other process has high decolorization power. Removal efficacy of iron powder-hydrogen peroxide process with H[2]O[2]=23.33 ml / L, pH=3, iron powder 2000 mg/L and 60 minute, was about 97.9% In general this investigation showed that, this method [Iron powder-hydrogen peroxide process] has high efficiency for removal of Azo dyes. But application this method in the industry, should be economically evaluated

Two-parameter isotherms of methyl orange sorption by pinecone derived activated carbon

The adsorption of a mono azo dye methyl-orange [MeO] onto granular pinecone derived activated carbon [GPAC], from aqueous solutions, was studied in a batch system. Seven two-parameter isotherm models Langmuir, Freundlich, Dubinin-Radushkevic, Temkin, Halsey, Jovanovic and Hurkins-Jura were used to fit the experimental data. The results revealed that the adsorption isotherm models fitted the data in the order of Jovanovic [X[2]=1.374] > Langmuir > Dubinin-Radushkevic > Temkin > Freundlich > Halsey > Hurkins-Jura isotherms. Adsorption isotherms modeling showed that the interaction of dye with activated carbon surface is localized monolayer adsorption. A comparison of kinetic models was evaluated for the pseudo-second order, Elovich and Lagergren kinetic models. Lagergren first order model was found to agree well with the experimental data [X[2]=9.231]. In order to determine the best-fit isotherm and kinetic models, two error analysis methods of Residual Mean Square Error and Chi-square statistic [X[2]] were used to evaluate the data

Textile anionic dyes recovery using tri-n-butyl phosphate as carrier through supported liquid membrane.

The recovery of anionic dyes Acid Red10 B (CI Acid Violet 54) and Acid Pink BE (CI Acid Red 183) in flat type supported liquid membrane (SLM) using tri-n-butyl phosphate as carrier was studied. The parameters studied were the effect of feed phase pH, stripping reagent concentration, string speed and initial dye concentration on permeability of dyes. The influence of salt concentration such as sodium chloride and sodium sulphate on the dye recovery was examined. The reusability of membrane and kinetics of transport were also studied. The optimum conditions of transport are feed phase pH 1 +/- 0.1, 0.1 M sodium hydroxide as stripping phase, stirring speed at 500 rpm. The maximum recovery under optimum conditions was observed as 94.2 % for Acid Red10 B and 85.7 % for Acid Pink BE. The maximum permeability was 11.0 x 10(-6) m/s for Acid Red10 B and 7.7 x 10(-6) m/s for Acid Pink BE.

Colour removal from textile waste water using bioculture in continous mode.

One of the environmental problems being faced by textile industry is the removal of colour from the dye wastewater prior to discharge to local sewage treatment facilities or adjoining water courses. During the past two decades, several physico-chemical methods like adsorption, chemical treatment and ion pair extractions were adopted and have been proved to be costly and less effective. Biological treatment methods are comparatively cheap and considered to be the best alternative with proper analysis and environmental control. With this in mind, an attempt was made to evaluate efficiency with mixed microbial cultures for the decolourisation of the dye wastewater in continuous mode operation. Laboratory scale models of anaerobic reactor, activated sludge process and sand filter were fabricated and operated in series. The activated bioclean was inoculated in the anaerobic reactor. The characteristics and treatability of the textile dye wastewater were analysed. The sample taken for the study was combined effluent collected from the equalization tank in Common Effluent Treatment Plant (CETP), Tirupur. The experiments were conducted for different organic loading rates. Parameters such as colour, pH, COD, BOD, suspended solids, total dissolved solids, chlorides and sulphates for both the influent and effluent were evaluated. The removal efficiency of the anaerobic process, activated sludge process and sand filter for the above said parameters were studied.

Removal of azo dyes from aqueous solutions using activated carbon as an adsorbent.

The potentiality of commercially available activated carbon has been investigated as an effective adsorbent to remove the dyes from aqueous solutions. The effects of pH of the solution, adsorbent dose, solute concentration and temperature on activated carbon for azo dyes such as acid orange 7 and direct red 31 have been evaluated. The percentage removal of the dyes has been found to be high at neutral pH. The dynamics of adsorption has been studied at different temperatures. The adsorption data follow Langmuir model as well as Freundlich model in the case of acid orange 7 whereas the data for direct red 31 fit into only Langmuir model.