Dye Bath Effluent Research Articles

Reusing Cotton Dye-Bath Effluent for Polyester Dyeing

Reusing Cotton Dye-Bath Effluent for Polyester Dyeing

Removal of Reactive Black 5 by UV-C assisted peroxydisulfate process: Effect of parameters, kinetic study, and phytotoxicity assessment

ABSTRACT Photochemical removal of Reactive Black 5 (RB5) was investigated by the UV-C assisted peroxydisulfate (UV-C/PDS) process. Parameters affecting the removal of RB5 were examined. Activation of PDS by UV-C light significantly improved the removal efficiency compared to direct photolysis or PDS alone. The removal of RB5 by UV-C/PDS process fitted well with the pseudo first-order kinetic model under all tested conditions. Almost complete removal of RB5 was achieved at the end of 120 min within the pH range of 3–7, whereas 90.7 and 89.4% removal efficiency values were observed at pH = 9 and 11, respectively. An increase in PDS dosage in the range of 0.25–1 mM led to a rise in removal from 48.5 to 97.3% after 120 min, and a complete removal was observed with a dosage higher than 2 mM. Pseudo firstorder rate constant (kobs) increased linearly with PDS dosage from 0.0058 to 0.0518 min−1 in the 0.25 mM − 2.3 mM concentration range. The removal efficiency decreased with an increase in the initial concentration of RB5 from 20 to 50 mg L−1 and an exponential correlation was observed between kobs and initial concentration of RB5. Scavenging experiments conducted using t-butyl alcohol and ethyl alcohol implied that both sulphate and hydroxyl radicals were involved in the removal of RB5. Adding HCO3 − decreased the removal of RB5 within the range of 1–30 mM. The presence of CI− showed a negative impact on the removal at low concentrations (1–15 mM) and NO3 − slightly inhibited the removal of RB5. With corresponding stoichiometric PDS dosage, almost a complete mineralisation was achieved for RB5 solution and simulated dyebath effluent after 720 min of reaction time. EE/O values were determined to be 91.0, 76.8, and 41.1 kWh m−3 order−1 for UV-C/H2O2, UV-C/PMS, and UV-C/PDS processes, respectively. The phytotoxicity tests indicated that the intermediates could be more toxic than the parent compound.

Assessment of textile industry effluent (untreated and microbially treated) induced genotoxic, haematological, biochemical, histopathological and ultrastructural alterations in fresh water fish Channa punctata.

The unregulated expulsion of untreated textile water into water bodies is a major hazard to aquatic ecosystems. The present investigation was contrived to estimate the impact of textile dye bath effluent (untreated and microbially treated) on fish Channa punctata. Untreated effluent-exposed fish showed extremely altered behaviour (air gulping, erratic and speedy movements, increased opercular activity) and morphology (deposition of dyes on skin and scales, high pigmentation, mucus exudation). Significantly increased micronuclei (1.61-, 1.28-, 1.38-fold) and aberrant cell frequency (1.37-, 1.45-, 1.28-fold) was observed in untreated group as compared to treated group after 15, 30, and 45 days of exposure. Tail length, % tail intensity, tail moment and olive tail moment were also enhanced in all the exposed tissues. However, maximum damage was noticed in gill tissues showing 1.19-, 1.37-, 1.34- and 1.50-fold increased TL, %TI, TM and OTM in untreated group as compared to treated group after 45 days of exposure. On comparing untreated and treated groups, increased blood parameters and significantly reduced white blood cell count (WBC) were noticed in treated group. Significantly enhanced alterations in biochemical parameters were also analysed in untreated group. Reduced alterations in enzymological levels of fishes exposed to treated effluent indicate lesser toxic nature of the degraded metabolites of dye. Histological analysis in fishes exposed to untreated effluent showed several deformities in liver (necrosis, congestion, fusion of cells and melanomacrophage infiltration) and gill tissues (necrosis, bending of lamellae and severe aneurysm). Scanning electron microscopy (SEM) analysis further reaffirmed the pathologies observed in histological analysis. Fewer structural alterations were noticed in treated effluent fishes. The results concluded that untreated effluent inflicted toxicity potential on morphology as well as physiological defects in fish, and the severity increased with increasing duration of exposure, whereas reduction in toxicity in microbially treated groups can be analysed for aquacultural purposes owing to their lesser toxic nature.

Evaluating dye recovery and reusability potential from dyebath effluent using forward osmosis membranes for minimum liquid discharge

This study focuses on the evaluation of dye recovery and reuse potential from denim and polyester effluents using forward osmosis (FO). A cationic surfactant, tetraethylammonium bromide (TEAB), was used as the draw solution (DS). After optimizing the DS and feed solution (FS) concentrations and temperatures in batch experiments, a DS concentration of 0.75 M was selected at a 60 °C temperature for the semi-continuous mode. It generated a high flux of 18 L/m2/h and a low reverse solute flux (RSF) of 0.4 g/m2/h with 100% dye rejection. Dye reconcentration of 82–98% was achieved in the dyebath effluents. The unique property of surfactants to combine hundreds of monomers into micelle resulted in negligible RSF. Reversible fouling was observed on the membrane active layer, and NaOH and citric acid cleaning achieved about 95% of flux recovery. The functional groups on the membrane's active layer remained undisturbed due to foulant interactions showing its chemical stability against reactive dyes. Recovered dye characterization using 1D proton nuclear magnetic resonance (1HNMR) analysis depicted a 100% structural resemblance to the original dye. Hence, it can be reused for dyeing the next batch. Diluted TEAB solution can be used as fabric detergent and softener within the same textile industry in the finishing process. A minimum liquid and persistent pollutant (dyes) discharge is achieved by adopting the methodology proposed in this work with a strong potential of translating it to an industrial scale.

A Combined Approach for the Treatment of Textile Dye Bath Effluent Using CO2 Gas

In this study, baking soda extraction from textile dye bath effluent has been investigated. The novel notion of employing amino acid additions to improve the standard Solvay method and thereby boost the efficiency of Na+ recovery has been investigated. Glycine, L-arginine, and L-alanine are three amino acid additions examined for their effect on enhancing Na+ recovery, and the best-suited additive is chosen. The dumping of brackish dye bath effluent, which has a high percentage of sodium chloride, causes textile dye baths from the textile industry. The primary goal was to remove Na+ (sodium) from the effluent using carbon dioxide gas, which has environmental benefits. Carbon dioxide (CO2) is the most common greenhouse gas, trapping heat and raising global temperatures, therefore contributing to climate change. The Solvay process is used to transform Na+ in salty wastewater into a valuable product. The effect of different operating variables such as NH4OH (ammonium hydroxide) concentration, reaction temperature, carbonation time, and carbon dioxide gas flow rate on bicarbonate production was investigated. Maximum sodium recovery of about 68 percent is attained under optimal circumstances. When compared with the regular Solvay process, the modified Solvay method has a greater recovery efficiency (33 percent). Amino acid addition (arginine) improved conversion efficiency while also lowering the process’s ammonia need.

Recovering and reuse of textile dyes from dyebath effluent using surfactant driven forward osmosis to achieve zero hazardous chemical discharge

This experimental study explores the feasibility of the reuse of dyes recovered from denim and polyester dyebath effluents using forward osmosis (FO) system to achieve zero hazardous material discharge. In batch experiments, the sodium dodecyl sulfate (SDS) at 0.5 M concentration generated an average flux of 3.5 L/m2/h (LMH) and reverse salt flux (RSF) of only 0.012 g/m2/h (GMH), while maintaining 100% dye rejection. This flux stability comes from the property of surfactants to form micelles and exert a stable osmotic pressure (π) above their critical micelle concentration (CMC). The low RSF is due to the greater micelle size. A colored fouling layer was formed on the membrane active layer (AL), which was easily removed using sodium hydroxide (NaOH) and citric acid. According to Fourier transform infrared spectra and atomic forces microscopy images of the AL, the interaction between foulants and membrane active groups did not significantly affect the physiochemical properties of the membrane. In the semi-continuous experiment, a very stable average flux of 7.3 LMH and RSF of 0.03 GMH was obtained using 0.75 M SDS as draw solution. The stacked 1D proton nuclear magnetic resonance analysis (1HNMR) spectra of both original and recovered disperse dyes showed 100% similarity, which validates the concept that the recovered dyes maintained their integrity during reconcentration and can be reused in the next batch dyeing process. Importantly, the diluted SDS concentration can be directly reused within the same textile industry in scouring and finishing processes. The processes of dye recovery and reuse developed in this study do not produce any waste or hazardous by-products and are suitable for scale-up and onsite industrial applications.

Nanocomposites of ternary mixed metal oxides (Ag2O/NiO/ZnO) used for the efficient removal of organic pollutants

A facile synthesis of nanocomposites of ternary metal oxides (Ag2O/NiO/ZnO) has been reported. Three ternary nanocomposites A/N/Z-1, A/N/Z-2, and A/N/Z-3 with different molar ratios of silver oxide (10 %, 20 % and 30 %, respectively) have been synthesized by decorating a binary N/Z (NiO/ZnO = 1:1) nanocomposite. The diameter of the particles in N/Z binary nanocomposite is approximately 31.59 ± 5.03 nm, and the size of the decorated silver oxide in the A/N/Z-3 ternary nanocomposite is 5.92 ± 1.36 nm as deduced from TEM analysis. The Ag2O/NiO/ZnO nanocomposites have efficiently catalyzed the reduction of various nitrophenols, dyes, and their mixtures. Among the synthesized nanocomposites, A/N/Z-3 has the highest silver oxide content that reduces 4-nitrophenol ([pNP] = 0.16 mM) in the shortest time (7 min). Therefore, A/N/Z-3 has been chosen to investigate other parameters for pNP's reduction, including the amounts of catalyst, pNP and sodium borohydride. A/N/Z-3 (6.41 μg mL−1) reduces different nitrophenols ([NP] = 0.16 mM) in following order: oNP (2-nitrophenol: 2 min) > mNP (3-nitrophenol: 2 min) > pNP (4-nitrophenol: 7 min) > 2,4,6TNP (2, 4, 6-trinitrophenol: 13 min) in the presence of sodium borohydride (40 mM). Similarly, A/N/Z-3 (6.02 μg mL−1, except for MB, the amount used was 29.41 μg mL−1) reduces different dyes (0.02 mM) in the following order: MO (methyl orange: 2 min and 30 s) > CR (congo red: 2 min and 30 s) > RB (rhodamine-B: 4 min) > MB (methylene blue: 9 min). Further, A/N/Z-3 reduces nitrophenols' mixture, dyes' mixture, simulated effluents (EFF1) sample and a real industrial sample (dye bath effluents: DBE) in 8 min, 8 min, 6 min and 12 min, respectively, and also reused up to five cycles. Hence, this highly efficient, inexpensive, and easily reusable robust catalyst can be used to remove toxic organic pollutants from industrial wastewater.

Comparison of ozonation, Fenton, and photo-Fenton processes for the treatment of textile dye-bath effluents integrated with electrocoagulation

This study aims to investigate treatment efficiency and evaluate the energy efficacy of integrated electrocoagulation system combined with ozonation, Fenton, and photo-Fenton processes for successful textile dye-bath effluents' treatment. In this regard, the characterization of physicochemical parameters such as pH, turbidity, salinity, total dissolved solids (TDS), total suspended solids (TSS), electrical conductivity (EC), and chemical oxygen demand (COD) was analyzed to estimate removal efficiency of each treatment process. Moreover, the electrical energy consumption of all aforementioned processes was measured individually to work out cost-effectiveness. Fenton process appeared to be ineffective for reducing COD and other parameters. While the overall performance of ECS alone showed far better results, COD and color removal efficiencies were 57.4%, and 40%, respectively. However, the application of ECS/O3 resulted in complete decolorization and almost 99.7% COD removal under optimized operating conditions including ozone flow 300 mg/h, pH 7.1, Temperature 25 °C. ECS/photo-Fenton process resulted in COD, and color removal of 95.6%, and 97%, respectively. Electrical Energy per Order of ECS was found 1.58 kWh/m3 for minimum removal of dyes and COD. ECS/Ozonation is responsible for 100% decolorization but at a very high cost. ECS/photo-Fenton process proved to be the second-best option in terms of treatment and energy consumption. Hence, an integrated treatment system of ECS with AOPs appeared to be the most feasible and eco-friendly. That could lead to the treated wastewater for reuse and recycling purposes within the industry.

Ag nanoparticles anchored on NiO octahedrons (Ag/NiO composite): An efficient catalyst for reduction of nitro substituted phenols and colouring dyes

The development of an efficient sustainable catalyst for effective removal of hazardous chemicals, viz. nitrophenols and organic dyes, from wastewater is a challenging task. Herein, facile synthesis of Ag/NiO composites by anchoring Ag nanoparticles (NPs) on NiO octahedrons with different amounts of Ag NPs (AN-5% (5% Ag), AN-10% (10% Ag) and AN-15% (15% Ag)) has been demonstrated. SEM (scanning electron microscopic) and TEM (transmission electron spectroscopic) images ensured the proper anchoring of spherical Ag NPs (particle size = 16.54 ± 1.88 nm) on octahedron particles of NiO, which was also ensured by XPS (X-ray photoelectron spectroscopy) analysis. Moreover, the resulting composites have an average surface area (49–52 m2g‒1) and pore size (2.39–2.26 nm). All three synthesized Ag/NiO composites (100 μL) catalyzed the complete reduction of para-np (4-nitrophenol: 0.1587 mM) within 2–3 min in the presence of 0.04 M NaBH4. Among them, AN-5% has been chosen because of the lowest anchored Ag (5%) to obtain the optimized catalyst's amount (50 μL) and concentration of para-np (0.1587 mM). AN-5% also exhibited excellent catalytic activity towards different nitro substituted phenols, viz. ortho-np (2-nitrophenol), meta-np (3-nitrophenol), para-np (4-nitrophenol) and tri-np (2,4,6-trinitrophenol). AN-5% displayed ∼100% catalytic efficiency for reducing meta-np in 2 min with the apparent first order rate constant (kapp) and normalized rate constant (Knor) as 1.99 s−1 and 398.14 s−1 g−1, respectively. Additionally, AN-5% (29.41 μg mL−1) reduced >95% of the colouring dyes (10 ppm) such as CONG-R (congo red: 95% in 6 min), METH-O (methyl orange: 97.5% in 7 min), METH-B (methylene blue: 98.3% in 10 min) and RHOD-B (rhodamine B: 99.2% in 5 min). AN-5% not only demonstrated catalytic reduction towards individual pollutants, but also showed excellent activity for reduction of the mixtures of nitrophenols/dyes and for treatment of simulated industrial effluent samples (EFF1, EFF2) and a real industrial sample (textile dye-bath effluent). AN-5% can also be reused up to several cycles with almost same efficiency and followed the Langmuir-Hinshelwood apparent first order kinetics model.

Photocatalytic Decolorization Simulated Textile Dyebath Effluent under Solar Light and Reuse it for Industrial Propose

In this work, the photocatalytic is related to simulated wastewater as well as recycling for industrial uses. Photocatalytic degradation of simulated wastewater content (Eosin Yellowish, Eriochrom Black T, Methyl Violet, EDTA, FeSO4.7H2O, NaCl, and NaOH) was utilized as a treatment approach in batch reactors within solar light in a heterogeneous slurry with the use of many concentrations regarding the commercial powder ZnO as photocatalysts semiconductors. We have tested many operation conditions like (catalyst concentration, pH, initial dye concentration and final water treated properties). The water quality related to treated wastewater is based on the nature of waste added during usage, the industrial water supply quality, and the treatment degree which is received via wastewater. After that, the quality data of wastewater is evaluated and indicated at waste-water treatment plant majorly for the disposal of the treated effluents or discharge requirements with regard to gross pollution parameter.

Energy efficiency of the advance physical system for the complete treatment of dye-bath effluents

Energy efficiency of the advance physical system for the complete treatment of dye-bath effluents

β-AgVO3 nanowires/TiO2 nanoparticles heterojunction assembly with improved visible light driven photocatalytic decomposition of hazardous pollutants and mechanism insight

In this report, novel β-AgVO3 nanowires/TiO2 nanoparticles heterojunction was synthesized first time using hydrothermal technique and employed for the photocatalytic decomposition of Rhodamine (RhB) dye, simulated dye-bath effluent and colourless compound i.e. ciprofloxacin (at natural pH) under visible light illumination. The prepared composite composed of β-AgVO3 nanowires over which the nanoparticles of TiO2 were distributed. The photocatalytic outcomes demonstrated that prepared β-AgVO3 nanowires/TiO2 nanoparticles heterojunction showed enhanced (93% degradation) catalytic properties for the decomposition of RhB dye under visible illumination in contrast to bare TiO2 (43%). Moreover, β-AgVO3/TiO2 exhibited 82% decomposition of simulated dye-bath effluent, signifying enough potential for treating industrial wastewater as well. Reactive species trapping experiments exhibited that OH and e− played pivotal role in the decomposition of RhB dye in aqueous phase. About 58% TOC drop in RhB solution (10 mg/L) was accomplished after 120 min of photocatalytic reaction. Further, the detailed mechanism for the decomposition of RhB dye was discussed.

Low energy electrochemical oxidation efficiently oxidizes a common textile dye used in Thailand

Organic dyes are extensively used worldwide in the textile industry. Thailand's textile industry, which is mostly composed of small- and mid-sized factories that produce wastewater streams, would benefit from efficient, small-sized, and easy to operate treatment technologies. Electrochemical oxidation (ECO) is an alternative to historic solutions (e.g., biological treatment, coagulation, membranes, ozone) to treat dyebath effluents and reuse the water for secondary, non-potable purposes. ECO is an advanced oxidation process capable of in-situ electrogeneration of hydroxyl radical to completely mineralize organic pollutants. This work demonstrates the capability of electrochemically-driven systems to efficiently decolorize and mineralize dyebath effluents containing anthraquinone dye Acid Green 25. Achieving color and chemical oxygen demand abatement to below effluent discharge limits was attained using only 100 mA cm−2. Breaking the aromatic rings successfully produced readily biodegradable, low molecular weight carboxylic acids and inorganic (ammonium, nitrate) total nitrogen below 7 mg-N L−1, which can be readily discharged to sewers or even urban surface waters. The competitiveness of the electrochemical system is analyzed using engineering figures of merit, and the impacts of operational variables are discussed in terms of removal percentage, efficiency, and electrical energy per order. Results suggest wide applicability as an alternative for treating textile manufacturing waste streams.

Treasure from dross: Application of agroindustrial wastes-derived thermo-halotolerant laccases in the simultaneous bioscouring of denim fabric and decolorization of dye bath effluents

In this research paper, thermo-halotolerant laccases from microbial fermentation of agroindustrial residues by Achromobacter xylosoxidans HWN16 (Hb9c) and Citrobacter freundii LLJ16 (Ie1c) were evaluated for their ability to decolorize synthetic dyes and also wash indigo from denim fabric. Denim bioscouring and dye decolorization were monitored at different incubation times and uniquely high dye concentrations. The application of the free laccases in denim bleaching had no empirical effect, when applied unaided. However, their homogenization with an oxidized mediator (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) yielded experiential effects after 6 h of incubation under orbital conditions, and improved discoloration of fabrics was observed with the aid of a dissection microscope. Furthermore, the dye baths were decolorized by the homogenates, after scouring of the fabrics, thereby producing colorless effluents. The results presented revealed the possibility of replacing conventional caustic and environmentally toxic approaches with cleaner sustainable methods for washing of denims, and dye decolorization.

Electrochemically-driven mineralization of Reactive Blue 4 cotton dye: On the role of in situ generated oxidants

Brazil is the fifth biggest global manufacturer of textiles and the fourth in cotton textile exports. Textile effluents contain organic dyes that are highly recalcitrant and difficult to oxidize by conventional physico-chemical and biological treatments. Mid-sized textile factories require reliable water treatment technologies of small physical foot-print that do no produce solid wastes to treat their manufacturing effluents. Electrochemically-driven technologies emerge as feasible alternative technologies that overcome barriers in the management of these industrial effluents. This work studies the application of electrochemical advanced oxidation processes on the treatment of dye bath effluents containing cotton dye Reactive Blue 4. Electro-Fenton treatment attains complete color removal with an electrical energy per order (EEO) of 7.4kWhm−3order−1, which represents an order of magnitude lower operational expenditure than electrochemical oxidation (54.8kWhm−3order−1). Simultaneous irradiation with UVA light in photoelectron-Fenton systems did not show any effect on RB4 degradation kinetics. But UVA irradiation increased the mineralization achieved after treatment, which enhanced current efficiencies ca. 2-fold respect to electro-Fenton.

Re-using the steel and bleach waste in advance oxidation processes (AOPs) for dye-bath effluent treatment

Re-using the steel and bleach waste in advance oxidation processes (AOPs) for dye-bath effluent treatment

Fabrication of novel carbon quantum dots modified bismuth oxide (α-Bi2O3/C-dots): Material properties and catalytic applications

The present work reports the facile and the template free sonochemical synthesis of a novel catalyst, α-Bi2O3/C-dots, for the degradation of indigo carmine (IC) dye, its simulated dyebath effluent and levofloxacin under visible light catalysis. The compositional, structural, optical and morphological analysis of α-Bi2O3/C-dots was studied using analytical, spectroscopic and microscopic techniques. X-ray diffraction (XRD) results confirmed the presence of a monoclinic phase of α-Bi2O3 in the nanocomposite and crystallite size of 28.75 nm. Photoluminescence (PL) and UV–vis diffuse reflectance spectra (UV-DRS) studies showed good optical properties and a band gap of 2.49 eV. The synthesized photocatalyst showed superior visible-light driven photocatalytic activity for the degradation of indigo carmine dye (86% dye degradation in 120 min) compared to pure α-Bi2O3 (57%). α-Bi2O3/C-dots also exhibited 79% degradation of antibiotic drug levofloxacin within 120 min, under optimized conditions of pH, catalyst dose and initial dye concentration. Scavenger studies revealed that hydroxyl radicals and electrons played predominant roles in the photocatalytic degradation of IC dye. With respect to total organic carbon (TOC) analysis, 68.8% total organic carbon reduction of the IC dye (10 mg/L) was observed under the same experimental conditions. The catalytic efficiency of C-dots in the photocatalytic process is explained by proposing a degradation mechanism.

Performance of a new ceramic microfiltration membrane based on kaolin in textile industry wastewater treatment

A ceramic microfiltration membrane with a porosity of 40.2%, mean pore diameter of 0.27 μm, and a flexural strength of 55 MPa was prepared and applied for treatment of two types of textile dye-bath effluents. The ceramic membrane had a water permeability of 1376 L/m2.h.bar and showed excellent corrosion resistance against basic medium. Considerable removal of COD (25%), TDS (31%), BOD (39%), turbidity (21%), sulphates (34%), chlorides (33%), and color (26%) from textile effluents was achieved in the microfiltration treatment along with complete (100%) removal of TSS. This study revealed that filtration of textile effluents using a sub-micron range ceramic membrane (0.27 μm) is more effective than traditional microfiltration membranes (2–10 μm). The flux data fitted well with the standard pore blocking model indicating that the removal of various contaminants is due to adsorption of solutes on the interior surfaces of membrane pores.

A one-pot approach: Oxychloride radicals enhanced electrochemical oxidation for the treatment of textile dye wastewater trailed by mixed salts recycling

Abstract The efficacy of a photo-assisted electrochemical oxidation for the mineralization of real textile effluents (wash water and dye-bath effluent) was investigated by employing a non-photoactive dimensionally stable anode in a tubular flow cell. Under optimized conditions, the photo-assisted electrochemical oxidation was performed at a pH of 2, with a chloride concentration of 2 g L−1, a current density of 10 mA cm−2, and a flow rate of 50 mL min−1. The process efficiency was assessed through ultraviolet–visible spectroscopy, high performance liquid chromatography, Fourier transform-Infra red spectroscopy, nuclear magnetic resonance spectroscopy, chemical oxygen demand and total organic carbon analyses. The results obtained have shown that, in case of wash water effluent, 96% of chemical oxygen demand and 68% of total organic carbon were removed in 180 min of photo-assisted electrochemical oxidation, whereas a simple electrochemical oxidation removed only 70% of chemical oxygen demand and 27% of total organic carbon, in the same time. The energy consumptions were about to 29.8 and 39.5 Wh g−1 of chemical oxygen demand in photo-assisted electrochemical oxidation and electrochemical oxidation. The higher efficiency of photo-assisted electrochemical oxidation is attributed to the formation of oxychloride radicals at acidic pH, as confirmed by electron paramagnetic resonance analysis. The analytical results revealed that the degradation mechanism of photo-assisted electrochemical oxidation is entirely different from that of electrochemical oxidation; in particular, the byproducts formed in the photo-assisted process are free from chlorinated organic compounds and exhibit zero toxicity towards Lemna minor. The photo-assisted electrochemical oxidation proved to be effective also in the case of dye bath effluents with a high organic load: about 90% of the chemical oxygen demand was removed within 5 h at 10 mA cm−1. The recovered salts from the color-free dye-bath effluent were recycled for further dyeing purposes.

Decolorisation of disperse dark blue 148 with ozone

The aim of this study is decolorisation of CI Disperse Dark Blue 148 dye by ozone treatment which is one of the most attractive alternatives for solving the problem of color in textile dyeing effluents. A venturi injection system added dyeing chamber for getting ozone from the ozone generator. And additive (acetic acid and dispersing agent) put in the dyeing. After the coloration, the experimental color, chemical oxygen demand (COD), pH, temperature (°C) and conductivity (μS/cm) were measured. The results encourage the use of the system for decolorisation trials as well as dyebath effluent recycling.