• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1081-1088
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• 2009

The performance of a electrocoagulation (EC) process was examined for the removal of Rhodamine B (RhB) using iron electrode. The effects of operational parameters such as electrode material (aluminum and iron), current density, NaCl dosage, intial pH and initial dye concentration on RhB removal efficiency were investigated. The optimum range for each of these operating variables were experimentally determined. The experimental results showed that the iron is superior to aluminum as sacrificial electrode material. The optimum time of electrolysis, current density, NaCl dosage and pH were 10 min, 1630 A/$m^2$, 4 g/L and neutral pH, respectively. Under these conditions, RhB was effectively removed (> 93.4%) and also more than 80% of COD was removed (> 88.9%) when the initial concentration of RhB was 230 mg/L. The electrical energy consumption in the above conditions for the color and COD of RhB removal were 10.3 and 10.8 kWh/kg RhB, respectively. The electrocoagulation process could be a promising technology to treat dye wastewater containing RhB.

• Environmental Engineering Research
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• v.25 no.4
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• pp.571-578
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• 2020

In this work, a detailed study on the electrochemical degradation of an azo dye, Orange G is performed using a platinum electrode. Indeed, the influence of the dye concentration (50-150 mg/L), the pH of the medium and the density of the electric current is studied on the rate of discoloration, the rate of mineralization, the efficiency of the electric current and the energy consumption. The UV-visible spectra of OG plotted against the degradation time show the decrease of the intensity of the characteristic dye peaks. In an environment rich in chlorides, all peaks disappear after 15 min of degradation. However, the peaks at wavelengths of 200 and 290 nm appeared after one hour of treatment. In K₂SO₄, the eliminated percentages are respectively 46, 54 and 61% for wavelengths of 245, 330 and 480 nm. This suggests that the degradation mechanisms in K₂SO₄ and KCl environments are not the same. In the middle rich in chlorides, the eliminated percentage of OG did not seem to be affected by the concentrations increase. These results confirm the hypothesis that electrochemical oxidation process is very favorable for concentrated pollutants discharge.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.35-43
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• 2010

This experimental design and response surface methodology (RSM) have been applied to the investigation of the electrocoagulation/flotation of dye wastewater. The electrocoagulation/flotation reactions were mathematically described as a function of parameters current (A), NaCl concentration (B), initial RhB concentration (C) and time (D) being modeled by use of the central composite design (CCD). The application of RSM using the CCD yielded the following regression equation, which is an empirical relationship between the RhB removal (%) and test variables in RhB removal (%) = $-300.42+129.21{\cdot}Current+46.99{\cdot}NaCl-0.11{\cdot}RhB-+43.71{\cdot}Time-5.67{\cdot}Current{\cdot}NaCl-3.18{\cdot}Current{\cdot}Time-2.41{\cdot}NaCl{\cdot}Time-19.79{\cdot}Current^2-2.27{\cdot}NaCl^2-1.59{\cdot}Time^2$. the model predictions agreed well with the experimentally observed result ($R^{2}=0.9728$). The estimated ridge of maximum response and optimal conditions for RhB removal (%) using canonical analysis was 99.4% (A: 1,77 A, NaCl concentration: 2.23 g/L, RhB concentration: 56.12 mg/L, Time: 9.98 min). To confirm this optimum condition, three additional experiments were performed and RhB removal (%) were within range of 86.87% (95% PI low)~111.93% (95% PI high) obtained.

• Clean Technology
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• v.13 no.3
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• pp.215-221
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• 2007

Biosorption is considered to be a promising alternative to replace the present methods for the treatment of dye-containing wastewater. In this study, sewage sludge was used as a biosorbent which could be one of the cheapest and most abundant biomaterials. The objective of this work is to develop a surface-modified biosorbent with enhanced sorption capacity and binding affinity. The FT-IR and potentiometric titration studies revealed that carboxyl, phosphateand amine groups played a role in binding of dye molecules. The binding sites for reactive dye Reactive Red 4 (RR 4) were identified to be amino groups present in the biomass. In this work, based on the biosorption mechanism, the performance of biosorbentcould be enhanced by the removal of inhibitory carboxyl groups from the biomass for practical application of the biosorbents. As a result, the maximum capacity of biomass was increased up to 130% and 210% of the increment of sorption capacity at pH 2 and 4, respectively. Therefore, chemically modified sewage sludge can be used as an effective and low-cost biosorbent for the removal of dyes from industrial discharges.

• Journal of Environmental Health Sciences
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• v.37 no.3
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• pp.218-225
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• 2011

Objectives: In this paper, a dielectric barrier discharge (DBD) plasma reactor was investigated for degrading the dye Rhodamine B (RhB) in aqueous solutions. Methods: The DBD plasma reactor system in this study consisted of a plasma component [titanium discharge (inner), ground (outer) electrode and quartz dielectric tube], power source, and gas supply. The effects of various parameters such as first voltage (input power), gas flow rate, second voltage (output power), conductivity and pH were investigated. Results: Experimental results showed that a 99% aqueous solution of 20 mg/l Rhodamine B is decolorized following an eleven minute plasma treatment. When comparing the performance of electrolysis and plasma treatment, the RhB degradation of the plasma process was higher that of the electrolysis. The optimum first voltage and air flow rate were 160 V (voltage of trans is 15 kV) and 3 l/min, respectively. With increased second voltage (4 kV to 15 kV), RhB degradation was increased. The higher the pH and the lower conductivity, the more Rhodamine B degradation was observed. Conclusions: OH radical generation of dielectric plasma process was identified by degradation of N, N-dimethyl-4-nitrosoaniline (RNO, indicator of OH radical generation). It was observed that the effect of UV light, which was generated as streamer discharge, on Rhodamine B degradation was not high. Rhodamine B removal was influenced by real second voltage regardless of initial first and second voltage. The effects of pH and conductivity were not high on the Rhodamine B degradation.

• Textile Coloration and Finishing
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• v.33 no.4
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• pp.202-209
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• 2021

Natural dyes are more expensive than synthetic dyes and the dyeing process, which is mainly immersion of dye, is complicated. For this reason, relatively small-scale production methods were predominant. However, awareness and interest in environmental sustainability is rising globally, and the use of synthetic dyes causes various environmental problems such as wastewater and CO₂ emission, so the consumption of natural dyes is increasing. In addition, interest in digital textile printing, an eco-friendly dyeing method that can produce products of various designs and uses less water, is growing. In this study, natural indigo dye (Indigofera tinctoria) was used as a raw material for Digital Textile Printing ink, and ¹⁴C (Biocarbon) present in it was measured to confirm whether it was derived from natural ingredients. The performance was confirmed by testing the pH, viscosity, electrical conductivity, surface tension, and particle size analysis of natural indigo ink. In addition, the performance of natural indigo DTP ink and printing fabric was evaluated by inspecting the change in color fastness and corresponding index substances before and after digital printing with natural indigo DTP ink on textiles. Through this, the possibility of commercialization of DTP ink and printing fabric using natural indigo was confirmed.

• Membrane Journal
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• v.33 no.6
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• pp.269-278
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• 2023

Enzyme Immobilized Membrane Bioreactors (EMBRs) are a novel method to treat dyes within wastewater. Due to their efficacy and high resistance to the environment, there has been a large amount of research being done in this area. There are a variety of ways to approach EMBRs that include both the enzyme itself and the structure of said enzymes. The bioreactor itself can be modified to suit the needs of the dye removal. Ranging from Enzymatic bioreactors to utilizing nanostructures such as graphene oxide or carbon nanotubes. Furthermore, nanoparticles such as TiO₂ can be used to enhance the EMBR further as well. The polymer-based membrane supporting structure also includes a variety of different ways to approach the problem of increasing efficacy. As seen, during the past decades, different approaches to this issue that utilize EMBRs have been done. This review aims to summarize the methodologies and describe the various improvements to EMBRs that have been made.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.79-85
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• 2006

Innovated technique to oxidize pollutants has been developed. The technique for this study uses plasma discharge in 2-phase (Air-Water) and is called Discharged Water Generating (DWG) system. It produces electric arc which generates not only the physical decomposing power against the pollutants but also oxidants to sterilize pollutants depending on the inlet gas species. These physical and chemical products play an important role in COD decrease and biodegradability enhancement. The enhancement of biodegradability for the refractory organic substances in aqueous solution was estimated in this study. Argon discharge reduced NBDCOD of EDTA from 58.7mg/L to 38.8mg/L, but oxygen discharge and ozonation reduced it to 37.74mg/L and 38.73mg/L respectively. Furthermore, Argon discharge changed 1181mg/L of NBDCOD of dye effluent into 606mg/L but oxygen discharge and ozonation changed it into 888mg/L and 790mg/L respectively.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.883-888
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• 2012

Anode electrode is one of the most important factors in microbial fuel cell (MFC). This study was conducted to investigate the effects of mediator as methylene blue (MB) and electrode surface area on the power density of MFC with sponge and carbon nano tube (CNT) electrode (SC). The SC electrode with MB (MC) showed the maximum power density increased from 74.0 $mW/m^2$ to 143.1 $mW/m^2$. The grid shaped sponge and CNT (GSC) electrode showed the maximum power density of 209.2 $mW/m^2$ due to the increase of surface area from 88.0 to 152.0 $cm^2$. The GSC electrode with MB (GMC) revealed the maximum power density of 384.9 $mW/m^2$ which was 5.2 times higher than that obtained from the MFC with SC. Therefore MB and increase of surface area led to enhance the performance of microbial fuel cell such as power density.

• Journal of the Korean Chemical Society
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• v.50 no.4
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• pp.321-327
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• 2006

red 1 and acid blue 92, anionic dyes, were removed from synthetic wastewater by the surfactant-modified clay minerals. Two different clays, such as Korean clay(M78) and Japanese clay(KJ) were treated with three different sulfactants, CTMA, DSDMA and TMSA. The surfactant-modified clay minerals such as M-1(CTMA), M-3(TMSA), KJ-1(CTMA) and KJ-3(TMSA), showed high removal efficiencies with dyes, while M-2(DSDMA) and KJ-2(DSDMA) could adsorb both dyes with relatively low efficiencies. Furthermore, almost 100% absorption of both dyes onto M-1(CTMA) and KJ-3(TMSA) revealed the possibility that these materials can be used for the removal of hazardous organic dyes from wastewater.