• Textile Coloration and Finishing
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• v.16 no.2
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• pp.34-40
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• 2004

This study was conducted to remove the reactive dyes by the Ozone demand flask method which are one of the main pollutants in dye wastewater, Ozone oxidation of three kinds of the reactive dyes was examined to investigate the reactivity of dyes with ozone, Trihalomethane formation potentials(THMFPs), competition reaction and ozone utilization on various conditions for single- and multi-solute dye solution. Concentration of dyes was decreased continuously with increasing ozone dosage in the single-solute dye solutions. THMFPs per unit dye concentration were gradually increased with increase of ozone dosage. By the result of THMFPs change with reaction time, THMFPs were rapidly decreased within 1 minute in single-solute dye solutions. Dey were increased after 1 minute of reaction time, and then they were consistently decreased again after longer reaction time. Competition quotient values were calculated to investigate the preferential oxidation of individual dyes in multi-solute dye solutions. Competition quotients$(CQ_i)$ and values of the overall utilization efficiency, no$_3$, were increased at 40mg/1 of ozone dosage in multi-solute dye solutions.

• Textile Coloration and Finishing
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• v.19 no.3
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• pp.26-36
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• 2007

This study was carried out to treat the aqueous solutions containing reactive dyes(RB19, RR120 and RY179) by the Ozone demand flask method and adsorption process using activated carbon fiber(ACF) which are one of the main pollutants in dye wastewater. Ozone oxidation of three kinds of the reactive dyes was examined to investigate the reactivity of dyes with ozone, competition reaction and ozone utilization on various conditions for single- and multi-solute dye solution. Concentration of dyes was decreased continuously with increasing ozone dosage in the single-solute dye solutions. Competition quotient values were calculated to investigate the preferential oxidation of individual dyes in multi-solute dye solutions. Competition quotients(CQi) and values of the overall utilization efficiency, ${\eta}O_3$, were increased at 40mg/l of ozone dosage in multi-solute dye solutions. ACF(A-15) has much larger specific surface area$(1,584m^2/g-ACF)$ in comparison with granular activated carbon adsorbent (F400, $1,125m^2/g-GAC$), which is commonly used, and most of pores were found to be micropores with pore radius of 2nm and below. It was found that RB19 was most easily adsorbed among the dyes in this study. In the case of PCP (p-chlorophenol) and sucrose, which are single component adsorbate, adsorption capacities of ACF(A-15) were in good agreement with the batch adsorption measurement, and saturation time predicted of ACF columns for these components was also well agreed with practically measured time. But in the case of reactive dyes, which have relatively high molecular weight and aggregated with multi-components, adsorption capacities or saturation time predicted were not agreed with practically measured values.

• Textile Coloration and Finishing
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• v.17 no.6 s.85
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• pp.11-19
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• 2005

Textile dyeing with vat dyes has the highest color fastness although one and the same dye of all vat dyes cannot always satisfy every color fastness requirement. So we examined cotton, nylon 6, and polyester fabrics dyed with vat dyes. Cotton, nylon 6 and polyester fabrics were dyed with vat dyes such as C. I. Vat Blue 1, Blue 19, Black 9, Green 1, Orange 2, and Violet 1 containing sodium hydrosulfite and NaOH. Oxidation were carried out by a sodium peroxoborate after dyeing. The dyed materials were soaped at the boil after oxidation. Especially hydrolysis and overreduction for dyed polyester with vats dyes containing -NHCO- and -NH- groups such as C. I. Vat Blue 6, Black 25, Black 27, Red 10, and Green 3 occurred. It seems that these phenomena are due to a high dyeing temperature. Wash and rubbing fastness of nylon are higher than that of cotton and polyester. Light fastness of cotton is higher than that of polyester and nylon.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.2077-2083
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• 2000

For the application of wet air oxidation(WAO) process reactive dyes, remazol blacks has been selected as the subject for this study. The rate of decomposition relating to the reaction temperature and catalyst has been summarized during the catalytic wet air oxidation reaction. When 1.5 gram per liter of platinum is added titanium-dioxide and the partial pressure is adjusted to 6 atmosphere at the reaction temperature exceeding $200^{\circ}C$, more than 95% of the remazol blacks dyes were decomposed. When the reaction temperature was raised to $200^{\circ}C$, $220^{\circ}C$ and $250^{\circ}C$, respectively, for 240 minutes after adding the catalyst, the remaining rate of ultraviolet absorbance had dropped significantly to 18%, 12%, and 4%. At the reaction temperature of $250^{\circ}C$, color removal efficiency was approximately 95% or more after 120 minutes from the beginning of the reaction.

• Journal of the Korean Graphic Arts Communication Society
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• v.12 no.1
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• pp.117-132
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• 1994

New methodolgies for the syntheses of unsymmetrical squarylium(SQ) dyes for organic photoconductors(OPC) were developed and photostabilities for these dyes were dicucced. These dyes absorbed at 640-690nm and exhibit high molecular extinction coefficient about 10. photodegradation rate of these dyes is acceralated in the presence if singlet oxygen sensitizer. On the other hand, the photodegradation rate os retarded by adding effective singlet oxygen quencher, such as 2:1 metal dithiolate. It is suggested that the photodegration of unsymmetrical SQ dye may be due to a photo-oxidation involving singlet oxygen.

• Advances in environmental research
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• v.9 no.3
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• pp.161-173
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• 2020

The removal of two dyes, namely Methylene Blue (MB) and Reactive Brillant Red (RR) from aqueous solution was investigated using magnetite iron coated pumice (MIP) composite in the Fenton-like oxidation process. A weight ratio of 2.5 g (with the molar ratio of Fe³⁺ to Fe²⁺ to be 2) (5%) of iron to the total pumice (50 g) was enabled during synthesis of catalyst. Surface composition and characteristics of the catalyst were assessed by SEM-EDX, FT-IR, Raman spectral analysis. The effect of the amount of pumice solely used or MIP, H₂O₂ concentration, pH and initial concentration of MB or RR dyes on Fenton-like process efficiency was investigated. EDAX spectrums of pumice and MIP showed that oxygen and silisium are the major elements. The Fe content of MIP increased to 2.24%. SEM, FT-IR and Raman spectrums confirmed the impregnation of Fe on pumice surface. The experimental results revealed that high removal rates of dyes could be obtained using MIP that demonstrated a higher stability for removal of MB dye. pH affected the removal efficiency of both dyes and the degradation of both dyes was sharply dropped when pH was increased above 4. The removal of dyes did not significantly change with increasing H₂O₂ concentration. Degradation rates of both MB and RR dyes increased 3.3 and 2.8 times with the use of MIP compared to pumice alone, respectively. Furthermore, MIP enabled a good removal efficiency at higher dye concentrations. It can be emphasized that MIP composite can be used in the heterogeneous Fenton-like systems considering the economic and easily separation aspects.

• The Journal of Natural Sciences
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• v.9 no.1
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• pp.9-17
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• 1997

We studied on the decoloring efficiency of a dying and finishing industrial wastewater containing reactive dyes in the ozone treatment system. The wastewater containing reactive dyes improved the decolorization by the ozone oxidation. In order to determine the optical conditions for ozonation, various operation factors such as initial wastewater concentrations, pH, temperature, and ozone dose were evaluated. Ozone utilization rate was improved in general with the increase of initial concentration of wastewater. And the decolorization speed or reactive dyes was more decreased in deep color of blue series than in light color such as yellow series. The colorization of wastewater containing reactive dyes was changed step through midle color depending upon increasing of ozone treated time. The efficiency of decolorization for wastewater was improved with the pH increased and the temperature of ozone treatment system decreased.

• Textile Coloration and Finishing
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• v.18 no.5 s.90
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• pp.53-60
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• 2006

The 1,3-bis(4-aminoaryl)squaraines showed color, change behavior, they were found to undergo reduction with sodium borohydride in solution to give colorless leuco compounds, which oxidized readily in air back to the colored squaraine dye. We have shown that initial observations indicated that the derivatives synthesized gave new donor-acceptor chromophores. It is also interesting to note than the oxidation of the leuco squaraines did initially produce a species absorbing about 630-680 wavelengths. The 1,3-squaraines have found many uses as near-infrared absorbers, laser dyes and photoconductive materials. Furthermore their color-change redox behavior has potential in the area of peroxidase-based bioassaysas oxidation sensitive indicator systems were investigated.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.10a
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• pp.115-116
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• 2008

The textile wastewater discharged from printing and dyeing processes is characterized by high chemical oxygen demand(COD), low biochemical oxygen demand(BOD), and heavy color. The release of dyes into the environment constitutes only small proportion of water pollution, but dyes are visible in small quantities due to their brilliance. In this study, We are investigated to optimization of Ozone Oxidation process for Decolorization.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2009.03a
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• pp.69-70
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• 2009