Zinc oxide-mediated removal and photocatalytic treatment of direct orange 39 dye as a textile dye (original) (raw)
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PHOTOCATALYTIC DECOLOURIZATION OF DIRECT ORANGE DYE BY ZINC OXIDE UNDER UV IRRADIATION
In this paper, photocatalytic decolourization of direct orange dye solution was made in the presence of commercial ZnO as catalyst under the artificial light (high pressure mercury lamp) as UV A source. Moreover the light intensity was measured. The decolourization of direct orange dye process was obeyed to pseudo-first order kinetics. Activation energies for dye was found to be 8.964 KJ mol–1 and the reaction is very fast, endothermic and spontaneously. The best conditions of decolourization for this dye was such as: initial dye concentration is 40 mg/L, best dose of ZnO is 350 mg/100 mL and the initial pH of an aqueous solution of dye is 9 were studied. Key words: Direct orange dye, Photocatalytic
Photocatalytic decolorization of dispersive yellow 42 dye in ZnO/UV-A System
This work is focused on the photocatalytic decolorization of dispersive yellow 42 dye as textile dye. The decolorization of this dye was done in present the suspension solution of the commercial ZnO and the artificial light (high pressure mercury lamp) type 125 Watt as UV-A source at light intensity equal to 1.48 x 10-7 Ensien. s-1. The kinetic study for photocatalytic decolorization process of this dye was obeyed to pseudo-first order. The optimal variations for the decolorization of the studied dye at 25 mg/L were found. The best dose of ZnO is equal to 300 mg/100 mL and the maximum value of the initial pH of an aqueous solution is 7.7. Moreover, the effect of temperature was studied; and found that the photoreaction was endothermic and non-spontaneous. The apparent activation energy is small value, that make the photoreaction of this dye is fast.
ROLE OF ZnO BULK AND NANOPOWDERS IN PHOTOCATALYTIC DECOLORISATION OF TEXTILE INDUSTRIAL DYES
2009
We report on comparison of zinc oxide nanoparticles with bulk powders as candidates for decolorisation of organic dyes in the textile industry. X-ray diffraction showed pure phase catalysts; while ultraviolet-visible (UV-vis) spectroscopy showed larger absorbance in a wide visible range of spectrum for bulk, compared to nanopowders. Two dyes, Methylene Blue (MB) and Methyl Orange (MO) were treated with these catalysts in solar light. UV-vis studies showed ZnO bulk to completely decolorise both the dyes in < 20 min; as against its nano form. When decolorised components were evaluated it was found that the treated components were much in the safety regime as prescribed by WHO standards and were found to be Na, Zn, S, SO 4 2-, NO 2 and NO 3-. Cell line studies performed on these treated samples showed the cell viability of ~ 100% on SiHa and B16F10 cell lines as well as on mouse primary fibroblasts, giving evidence of non-toxicity of the catalyst, as well as the byproducts upon treatment, with bulk nanopowders to be better than their nano-counterparts. Defects-driven wider absorption of the bulk samples in the visible optical regime is envisaged to be the probable reason for better decolorisation efficiency of ZnO bulk samples.
International Journal of Photoenergy, 2013
To solve the environmental challenge of textile wastewater, a UV/ZnO photocatalytic system was proposed. The objective of this study was to prepare a photocatalytic system by utilizing both cold cathode fluorescent light (CCFL) UV irradiation and steel mesh supported ZnO nanoparticles in a closed reactor for the degradation of azo dye C.I. Orange G (OG). Various operating parameters such as reaction time, preparation temperature, mixing speed, ZnO dosage, UV intensity, pH, initial dye concentration, and service duration were studied. Results presented efficient color and total organic carbon (TOC) removal of the OG azo dye by the designed photocatalytic system. The optimal ZnO dosage for color removal was 60 g m−2. An alkaline pH of 11.0 was sufficient for photocatalytic decolorization and mineralization. The rate of color removal decreased with the increase in the initial dye concentration. However, the rate of color removal increased with the increase in the UV intensity. The stee...
Journals of Community Health Research, 2015
Introduction: In this research mixed ZnO and TiO2 was used for degradation of an azo dye (Direct Blue 71). Material and Methods: In comparison with just TiO2 or ZnO as photocatalyst, mixed photocatalyst (ZnO/TiO2) is more efficient catalyst for degradation of dye under UV irrad iation. The progress of the reactions was monitored spectrophotometrically by measuring the absorbance of dye at special wavelengths. The effects of various parameters such as ZnO/TiO2 ratio, amount of photocatalyst, pH, init ial dye concentration and irradiation time on decolorization rate were systematically investigated. Results: Results show that approximately 90 % of Direct Blue 71 has been eliminated after 70 minutes and optimized condition.
Drinking Water Engineering and Science, 2017
In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, TiO 2 , and SnO 2 to identify a low-cost photocatalyst for dye degradation. The obtained samples of ZnO, TiO 2 , and SnO 2 were characterised by X-ray diffractogram (XRD), scanning electron microscope imaging, and UV-VIS diffuse reflectance spectroscopy. The decolourisation of three structurally diverse dyes, namely crystal violet, basic blue, and methyl red under solar irradiation, was used to evaluate the photocatalytic activities of three metal oxides. The photocatalytic activities of the received three metal oxides were tested with the photocatalytic degradation of dyes and compared with Degussa P-25. Dye solutions with each metal oxide at initial pH 9 were subjected to irradiation under sunlight and monitored for up to the stage of complete decolourisation. The results indicate that ZnO exhibited the highest photocatalytic activity as compared to TiO 2 and SnO 2 as well as that of Degussa P-25 (TiO 2). The photocatalytic dye decolourisation rates with ZnO were 1.14-1.35, 1.70-3.1, and 4-8.5 times higher than those of the Degussa P-25, TiO 2 , and SnO 2 , respectively. The percentage COD removal was studied for ZnO and partial removal was observed at the decolourisation stage. To enhance photocatalytic activity of AR grade ZnO, it was loaded with Ag metal and about 20 % enhancement in the activity was observed.
Photo-Degradation of Reactive Yellow 14 Dye (A Textile Dye) Employing ZnO as Photocatalyst
In this paper, the reactive yellow 14 dye solution was removed from aqueous solution in the presence of commercial ZnO (mean crystallite size is 44.116 nm) under the UV A light. The decolourization of dye process was obeyed to pseudo-first orderki-netics. The optimum conditions of decolourization for this dye such as: initial dye concentration 50 mg/L, best dose of ZnO 350 mg/100mL and initial pH of aqueous solution of dye 6.75 were studied. Activation energies for dye were found to be 27.244 kJmol −1. The photoreaction process was observed to be endothermic reaction and less randomness.
Photocatalytic removal of acid orange 7 azo dye by suspended and immobilized zinc oxide
DESALINATION AND WATER TREATMENT, 2020
Acid Orange 7 (AO7) is one of the most widely used azo dye for textile industry and not easily removed via conventional biological wastewater treatment process. The photocatalytic process combining ultraviolet (UV) and zinc oxide (ZnO) in the suspended state or immobilized on the concrete plate was used to remove AO7 in this study. The effects of initial pH (2-11), UV lamp power (8-40 W), ZnO dosage (2.58-25.8 g/L for suspended reactor and 20-200 g/m 2 for immobilized reactor) and initial AO7 concentration (10-200 mg/L) on AO7 removal were systemically investigated in batch tests. Under the optimum conditions (neutral pH of 7, UV lamp power of 32 W, ZnO dosage of 10.32 g/L for suspended reactor and 80 g/m 2 for immobilized reactor, initial AO7 concentration of 50 mg/L), AO7 removal reached 97% and 98% after 60 and 360 min for suspended and immobilized reactors, respectively. AO7 removal followed by first-order reaction kinetics with decreasing rate constant and energy consumption with increasing initial AO7 concentration for both reactors. The photocatalytic efficiency of UV/ZnO in the immobilized reactor was significantly lower than in the suspended reactor but could be improved via increasing ZnO coated concrete plate area (i.e., ZnO active surface area).
This study describes the results for series of experiments on photocatalytic decolourization of methyl green dye from aqueous solution in the presence of commercial ZnO suspension. The photocatalytic decolourization has been studied as a function of initial dye concentration, best dose of ZnO, initial pH of aqueous solution, and temperature by regular intervals from experiments. The decolourization of methyl green dye process was found to follow pseudo-first order kinetics with the use of artificial UV (A) light sources. The optimum dye and catalyst concentration was measured and found equal to be 50 ppm and 700 mg/ 200 mL-1 respectively. The best value of pH for the photocatalytic decolourization of methyl green dye in the presence of ZnO suspension is pH 5.4. The Photocatalytic decolourization reaction of dye was endothermic and found the rate of reaction increased with increasing temperature. Arrhenius plot obtains that the activation energy for this reaction is equal to 24. 914 kJ mol-1, this value is small that beyond to be associated with the transport of photoelectrons through the catalyst to the adsorbed oxygen on the surface
Journal of Advanced Chemical Sciences, 2016
Commercial ZnO (c-ZnO) and prepared ZnO (p-ZnO) were applied under UV and solar light irradiation for evaluating the heterogeneous photocatalytic degradation of Remazol Black B (RBB) solutions. A comparative study of the experimental results demonstrates that, c-ZnO is more efficient for removing RBB than p-ZnO. The effects of various operational parameters such as the concentration of RBB, amount of ZnO and irradiation time have been studied and the optimized conditions for maximum removal of the RBB were determined and compared. The photodegradation kinetics was studied with modified Langmuir-Hinshelwood mechanism, which reveals the pseudo first order kinetics for photodegradation of RBB in the presence of p-and c-ZnO. Furthermore, Experimental results also demonstrate that photocatalytic activity for both types of ZnO is higher under solar light irradiation as compared to UV light.