scholarly journals Study of C.I. Acid Orange 7 removal in contaminated water by photo oxidation processes

2013 ◽  
Vol 10 (1) ◽  
pp. 16-23 ◽  

C.I. Acid Orange 7 (AO7) commonly used as a textile dye and could be degraded by UV/ZnO, UV/H2O2 and UV/H2O2/Fe (III) (photofenton) processes. In the photocatalytic degradation of dye by UV/ZnO process, effect of some parameters such as UV irradiation time, presence of ZnO and UV irradiation, pH, concentrations of ZnO, dye, H2O2 and ethanol was examined and first order reaction rate constant was calculated equal to 2.39×10-2 min-1 at experimental condition. The semi-log plot of dye concentration versus time was linear, suggesting first order reaction. Efficiency of photodegradation process in the absence of ZnO photocatalyst and UV light was small. Increasing the UV irradiation time increased AO7 removal. Ethanol had inhibitory effect on this process. Maximum AO7 removal was seen at neutral pH area. In the UV/H2O2 process, effect of some parameters such as presence of H2O2 and UV irradiation, amount of H2O2, effect of pH and addition of bicarbonate on the efficiency of dye removal were examined. Absence of each of UV irradiation or H2O2 decreased AO7 removal efficiency near to zero. Increasing H2O2 concentration increased dye removal to some extent but at higher H2O2 concentrations, dye removal efficiency did not increase. Increasing pH to value about 9 increased the AO7 removal efficiency and increasing bicarbonate anion concentration decreased it. Rate constant of AO7 removal by this process was calculated to be equal to 4.221×10-1 min-1 at experimental condition. Also, the order of UV/ H2O2/Fe (III) > UV/ H2O2 > UV/Fe (III) > H2O2/Fe (III), was seen for AO7 removal efficiency of these processes. Increasing Fe (III) and oxalate concentration increased dye removal efficiency.

2019 ◽  
Vol 6 (3) ◽  
pp. 157-170
Author(s):  
Amirreza Talaiekhozani ◽  
Abbas Heydari Chaleshtori ◽  
Farhad Banisharif ◽  
Zeinab Eskandari ◽  
Mohammad Nasiri ◽  
...  

Background: Industrial dyes are toxic and carcinogenic, therefore, they should be removed from wastewater. The aim of this study was to investigate the removal of acid orange 7 Dye from wastewater using ultraviolet (UV) radiation, MgO nanoparticles, ultrasonic method alone and in combination with each other. Methods: The effects of some factors such as temperature, pH, hydraulic retention time (HRT), UV power, and concentration of MgO nanoparticles on the removal of Acid Orange 7 dye from synthetic wastewater using different methods were investigated. Also, adsorption isotherms for MgO nanoparticles and kinetics for UV radiation were investigated. Results: The optimum HRT was 55 minutes while the temperature was not effective in dye removal using the ultrasonic method. Under optimum conditions for UV irradiation method (HRT = 70 minutes, UV power = 170 mW/cm2, and temperature = 10˚C), 58% of the dye was removed. However, under optimum conditions for MgO nanoparticles method (HRT = 15 minutes, temperature = 20˚C, and ratio of MgO nanoparticles to the initial dye concentration = 67.2), 82% of the dye was removed. By combining these methods, the dye removal efficiency was significantly increased. The combination of ultrasonic method and MgO nanoparticles had no significant effect on increasing the dye removal efficiency from wastewater. It was revealed that dye removal using UV radiation can be described by the first-order kinetics. Conclusion: According to the results, UV radiation has a synergistic effect on the dye adsorption process by MgO nanoparticles. Therefore, the combination of these methods can be effective for the removal of dye from wastewater.


2013 ◽  
Vol 9 (2) ◽  
pp. 132-136

Photocatalysis by titanium dioxide (TiO2) is a water treatment method. Pseudomonas aeruginosa is a microorganism resistant to chlorine and UV-C irradiation. TiO2 photocatalytic technology can destroy bacteria, which are resistant to oxidative destruction of cell membrane caused by sole UV irradiation. This study aims to investigate the total mineralization of the bacterium (P. aeruginosa) to the extent of death and cell-mass destruction using TiO2 photocatalytic oxidation process. In this work the effects of parameters such as amount of TiO2, irradiation time, initial concentration of bacterium, presence of ascorbic acid and effect of cell wall on removal of P. aeruginosa were studied. The data, which were obtained in this study, showed that the optimum concentration of TiO2 was 325 ppm. Also at the initial concentration of TiO2 equal to 325 ppm and initial microorganism MPN / 100 ml equal to 300 and after 75 min UV irradiation time, P. aeruginosa removal efficiency was 94.3 %. Removal efficiency of P. aeruginosa in the absence of TiO2 or UV irradiation was very low. Decreasing the concentration of microorganisms increased its removal efficiency. Removal efficiency of spheroplast cells was more than intact cells of P. aeruginosa, which shows the important role of cell wall on cell resistance against chemical agents. Ascorbic acid had inhibitory effect on this process.


Author(s):  
Azita Mohagheghian ◽  
Seyydeh-Amene Karimi ◽  
Jae-Kyu Yang ◽  
Mehdi Shirzad-Siboni

AbstractIn this study, photocatalytic degradation of Acid Orange 7 (AO7) by tungsten oxide nanopowder under UV irradiation was investigated with variation of pH, WO


2019 ◽  
Vol 48 (3) ◽  
pp. 1095-1107 ◽  
Author(s):  
Meng-Jung Tsai ◽  
Jheng-Hua Luo ◽  
Jing-Yun Wu

A rhombus (4,4) grid showing two-fold 2D + 2D → 2D interweaved nets appeared to be a good adsorbent to selectively adsorb and separate anionic methyl orange (MO) and acid orange 7 (AO7) dyes over cationic methylene blue (MB) and malachite green (MG) from water with high adsorption capacities in both darkness and daylight.


Molekul ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 30
Author(s):  
Dian Windy Dwiasi ◽  
Suyata Suyata

Colour removal from textile wastewater has been a matter of considerable interest during the last two decades, not only because of the potential toxicity of certain dyes but often due to their visibility in receiving waters and to their low biodegradability. Due to the limited success of some physical and chemical techniques for the treatment of dye effluents it is necessary to develop destructive systems leading to complete mineralization or, at least, to less harmful or easy-to-treat compounds. Oxidation processes using ferrate (FeO4)2- have been found to be very effective in the degradation of dye pollutants and for the treatment of waste waters from the textile industry.Acid Orange 7 (AO7) commonly used as a textile dye and could be degraded by ferrate oxidation processes. In the oxidation degradation of dye by ferrate process, effect of some parameters such as time, pH, and molar ratio of dye was examined at experimental condition. AO7 removal by this process was calculated to be equal to 12 minute at experimental condition. Ferrate can oxidize acid orange 7 effectively at optimum pH of 9.8, with the molar ratio of ferrate : acid orange 7 at 4:1. The percentages of acid orange 7 degradation reached to 98.9%.


2003 ◽  
Vol 48 (6) ◽  
pp. 133-139 ◽  
Author(s):  
D. Méndez-Paz ◽  
F. Omil ◽  
J.M. Lema

It was found that 1-amino-2-naphthol, an intermediate generated during the anaerobic degradation of Acid Orange 7, is a redox mediator which plays a significant role in the transport of electrons to the dye, thus giving to the whole process an autocatalytic nature. Evidences of the autocatalytic behaviour were observed in experimental data previously obtained under batch and fed-batch conditions. In this paper, a kinetic model considering all these factors is proposed and validated. In batch assays, this model agrees satisfactorily with the experimental data. In the case of fed-batch assays, the autocatalytic model only can be applied satisfactorily after the first feeding, since the degradation of Acid Orange 7 after the second and third feedings followed a first-order kinetic. This fact can be explained due to the presence of the redox mediator previously generated during the reactions that took place after the first feeding.


2016 ◽  
Vol 126 ◽  
pp. 197-206 ◽  
Author(s):  
W. Hajjaji ◽  
R.C. Pullar ◽  
J.A. Labrincha ◽  
F. Rocha

Author(s):  
Raja Balasaraswathi S and Kiruba T

The textile industry is one of the major industries contributing to water pollution. The wet processing of textiles involves the usage of a wide variety of chemicals and dyes. This water-intensive process can potentially affect the water bodies by its effluents. The treatment of dye effluents and reusing of the water could be the possible solution to reduce the impact. Adsorption is one of the most common methods used for textile effluent treatment. Various bio-adsorbents are explored to make the adsorption more sustainable. Nigella Sativa (Black cumin) seeds and its oil are having good medicinal value. The seed-waste left after the oil extraction is found to have active components that can be used as an effective bio-adsorbent. The dye removal efficiency of Nigella Sativa seed-waste is investigated under different experimental conditions (varied adsorbent dose, temperature, pH, and contact time) for reactive dyes. The maximum removal efficiency of 91% is obtained at the optimized experimental condition. Thus the study emphasizes that the no-cost Nigella Sativa seed-waste can be used as an effective bio-adsorbent for reactive dye removal from dye effluents.


2019 ◽  
Vol 6 (3) ◽  
pp. 203-213 ◽  
Author(s):  
Marzieh Bagheri ◽  
Esmail Mardani

Background: Today, due to increasing usage of dyes in various industrials and their destructive effects on health and environment, it is necessary to remove them from industrial wastes. Although there are few studies on the use of rice bran modified with polyaniline (RB/PANI) for removal of different dyes, but the effect of this adsorbent on the removal of Acid Orange 7 (AO7) dye has not been evaluated yet. Therefore, this study was conducted to investigate the removal of AO7 dye by RB/PANI as an adsorbent. Methods: The adsorbent characteristics were determined using scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. Also, the adsorbent surface area was measured by Brunauer–Emmett–Teller (BET) technique. The method of one-factor-at-a-time was used to optimize various factors including pH, temperature, and adsorbent dosage. Results: The optimal values for the factors affecting AO7 dye removal were calculated. It was revealed that the maximum dye removal was obtained at pH = 3, temperature = 25˚C, dye concentration = 30 mg/L, adsorbent dosage = 30 mg/L, and contact time= 60 minutes. The maximum removal percentage for RB/PANI was 97.13%. It was also revealed that Langmuir isotherm is the best fitted isotherm model. Conclusion: According to the results, the polyaniline-modified rice bran could be used as an excellent adsorbent for the removal of AO7 from aqueous solutions. The maximum dye removal efficiency for AO7 was obtained at pH = 3. Also, it was revealed that AO7 dye removal follows the pseudo-secondorder kinetic model and it is a spontaneous process.


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