Decolorisation of Remazol vinyl sulphone reactive dyes by potassium permanganate

Three Remazol vinyl sulphone‐based reactive dyes were selected to investigate their decolorisation by potassium permanganate, in relation to pH, concentration of potassium permanganate and time. The amount of colour removal was measured by ultraviolet–visual spectrometry and it was found that potassium permanganate only partially degraded the dye solution; this was also proved by the percent removal of chemical oxygen demand and total organic carbon. Decolorisation was observed to increase when the pH of the dye solution was decreased. Up to a pH level of 5, the decolorisation efficiency is very much slower, but as the pH level shifts towards 2 the rate of decolorisation becomes relatively faster, while a further decrease in pH results in a rapid change in decolorisation. The concentration of potassium permanganate also showed significant effects on the decolorisation. Rapid decolorisation was observed within 10 min for all three dyes, but after that time the decolorisation became slower.     

Decolorisation of aqueous dye solutions by low‐cost adsorbents: a review

Effluent generated by the textile industry can be highly coloured. Before the waste is disposed into receiving waters, colour removal is an important consideration. Because of their complex molecular structures, dyes present in the textile wastewater are not removed easily by conventional wastewater treatment processes. They are fairly stable to light, as well as heat, and resist biodegradation, thus posing a challenge to conventional physico‐chemical and biological treatment methods. Although adsorption technology using activated carbon has been considered to be an effective and proven technology, it has its limitations as it is expensive and necessitates regeneration. As cost is an important consideration in most developing countries, efforts have been made to explore the possibility of using various low‐cost alternatives that are biodegradable, abundant, readily available, and are derived from waste materials. This article is a compilation of the investigations carried out by numerous researchers (from 2002 onwards) on the effective use of different kinds of low‐cost adsorbents for the removal of specific dyes from textile wastewater.     

Decolorisation of reactive dye wastewater and the effect of surfactants using laccase

Laccase (benzenediol, oxidoreducase; Enzyme Commission Number) is a multi‐copper oxidase from biomass. Laccase enzyme recycling on molecular oxygen as an electron acceptor can be applied for the decolorisation of synthetic dyes. The decolorisation of 49 commercial reactive dyes using laccase was investigated. The effects of diverse structure surfactants on decolorisation are discussed. The absorption spectra of reactive dyes after a laccase biodegradable reaction were analysed. Reactive dyes based on anthraquinone and azo structures could be decolorised using the enzyme and their chemical structures broken. Reactive dyes based on an anthraquinone structure were easier to decolorise than those based on an azo structure. Surfactants could affect the decolorisation of dyes with an enzyme. The effect of nonionic surfactant on the decolorisation of anthraquinone dyes was the reverse. The cationic surfactant could improve the decolorisation rate of diazo dye. The effect of the anionic surfactant on dye decolorisation was small. Most commercial reactive dyes could be decolorised and biodegraded using a laccase enzyme under mild conditions. Laccase enzyme biotechnology has potential applications in the decolorisation of reactive dye wastewater.     

Decolorisation treatments of azo dye waste waters including dichlorotriazinyl reactive groups by using advanced oxidation method

Decolorisation treatments of azo dye waste waters, which include dichlorotriazinyl reactive groups, were investigated by using ultraviolet (UV) radiation and hydrogen peroxide at various exposure times. Decolorisation time decreased when UV radiation power and hydrogen peroxide concentration increased. Colour removal reached 98.0–99.5% by using this method. Some environmental parameters of decolorised waste water, such as biological oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total inorganic carbon (TIC), total carbon (TC), adsorbable organohalides (AOX), sulphate and chloride, were determined. It was concluded that TOC, COD and AOX decreased while BOD increased and sulphate ions remained unchanged. These results suggested that the dye molecules were totally destroyed and some of these decomposition products were removed as carbon dioxide and water to some degree.     

Decolorisation and degradation kinetics of reactive dye wastewater by a UV/ultrasonic/peroxide system

The decolorisation of reactive dyeing wastewater with ultraviolet radiation and ultrasonic vibration in the presence of hydrogen peroxide was investigated by a batch operation system. Kinetic studies of the reactive dye were conducted on the effects of pH and peroxide dosage, and the performance of ultrasonic vibration on the oxidation process was also investigated. It was found that the degradation of the reactive dye followed a pseudo-first-order kinetic model at different pH and peroxide dosages. The relationships between the rate constants and pH, as well as peroxide concentration, were established.     

Decolourisation and detoxifying of Remazol Red dye and its mixture using Fenton's reagent

A systematic approach was followed to optimise pH, temperature and the doses of FeSO₄ and H₂O₂ for Feton's reagent (FR) to decolourize and detoxify the solutions containing of Remazol Red 120 (RR) dye and its mixture with Remazol Brillant Blue (RB) and Remazol Yellow 84 (RY) reactive dyes. The acute toxicity of each dye composition was measured using D. magna. Optimum pH for RR singly used and for the dye mixture was found 3.5 while optimum temperature was determined 50°C, 40°C and 30°C for 100 mg/l of RR, 200 mg/l of RR and the dye mixture, respectively. More than 98% of colour and 92% of COD removal were obtained for the dye solutions. For obtaining high colour and COD removal H₂O₂ concentration had to be increased 3 times when RR concentration was doubled whereas FeSO₄ was to be increased 2.5 times for the dye mixture. The results obtained indicate that FR can be assurely used for complete toxicity removal and obtaining high colour and COD efficiency with no toxic effluent on D. magna for the dye solutions studied. Acute toxicity test with H₂O₂ was useful to evaluate the complete oxidation resulting in practically no residual H₂O₂ (<3 mg/l) in the solution.     

The effects of alternating current electrocoagulation on dye removal from aqueous solutions

The main goal of this study is to investigate the effects of alternating current (AC) on dye removal from aqueous solutions by electrocoagulation (EC). An EC system with parallel-connected aluminium electrodes was operated in batch mode. Two different aqueous dye solutions were used: one was obtained from Dianix Yellow CC (DY) and the other was obtained using Procion Yellow (PY). The experiments employing direct current (DC) were carried out using a DC power supply. The AC experiments were conducted using rectangular wave, which is produced with an adjustable time relay connected to the output of DC power supply. This current is called alternating pulse current (APC) in order to refer AC system in this study. Total organic carbon (TOC) and dye removal efficiencies were measured to assess treatment efficiency. Operating cost was calculated for both power supply systems and alternating pulse current was found superior to direct current for the treatment of reactive and disperse dyes used in this study.     

芬顿法处理活性艳红X-3B的试验优化及降解规律

通过试验方法优化,研究了芬顿体系中pH值、温度、H₂O₂投加量以及过氧化氢/硫酸亚铁摩尔比C(H₂O₂)/C(FeSO₄)对活性艳红X-3B脱色及总有机碳(total organic carbon,TOC)去除率的影响。结果表明:初始pH值对脱色率和TOC去除率的影响均最大。在正交试验的基础上,通过单因素试验进一步优化了反应条件,得出芬顿法去除活性艳红X-3B的最佳反应条件为pH=3、H₂O₂投加量为2.5 mmol·L^-1、C(H₂O₂)/C(FeSO₄)=10时,模拟废水的脱色率可达98.93%,TOC去除率可达48.81%。此外,芬顿体系的反应速率受温度的影响较大,色度去除符合二级动力学模型,根据Arrhenius公式计算得出活性艳红X-3B在芬顿体系中的反应活化能约为107 kJ·mol^-1。     

Decolorisation of a monoazo disperse dye with Candida tropicalis

Decolorisation of a heterocyclic monoazo disperse dye by the yeast species Candida tropicalis growing in mineral salt medium has been investigated. The effects of nutritional as well as environmental factors on the decolorisation efficiency were studied. Though Candida tropicalis displayed good growth in aerobic conditions, the colour removal was best under anoxic conditions. The degradation products of the decolorisation experiments under aerobic, as well as anoxic, conditions have also been identified.     

Degradation of Remazol Black B dye and its simulated dyebath wastewater by advanced oxidation processes in heterogeneous and homogeneous media

This study focused on the degradation of hydrolysed Remazol Black B (CI Reactive Black 5), a common diazo reactive dye, in aqueous solution. In the presence of various dye auxiliary chemicals a typical Remazol Black exhausted dyebath liquor simulated, which was then treated with homogeneous [ozonation with hydroxy ions, and Fe(II) or Fe(III) with hydrogen peroxide] and heterogeneous (titanium dioxide with UV-A irradiation) advanced oxidation processes. Treatment performance of the investigated advanced oxidation systems was comparatively assessed in terms of the environmental sum parameters total organic carbon, biochemical oxygen demand and spectrophotometric measurements. The results obtained clearly reveal that the investigated advanced oxidation processes are capable of completely decolourising and partially mineralising the dye solution and its simulated dyebath effluent under predetermined reaction conditions. During the application of alkaline ozonation at an ozone dose of 2340 mg/ml, a three-fold biodegradability enhancement was observed.     

臭氧强化电絮凝处理直接耐晒大红4BS模拟染料废水

采用臭氧强化电絮凝法处理直接耐晒大红4BS模拟染料废水,研究了染料脱色的影响因素及其COD_Cr去除动力学。考察了电流密度、溶液初始pH 值、染料初始浓度、支持电解质浓度、反应温度和臭氧流量对臭氧强化电絮凝法处理4BS染料脱色效率的影响。结果表明,电流密度15 mA·cm^-2,pH值10.0,4BS染料初始浓度100 mg·L^-1,支持电解质浓度3000 mg·L^-1,臭氧流量06 L·h^-1,20 ℃下反应50 min后4BS脱色率达94％以上。COD_Cr去除符合拟二级动力学。     

Biosorption of a reactive textile dye from aqueous solutions utilizing an agro-waste

In the present study a low-cost waste biomass derived from canned food plant, was tested for its ability to remove reactive textile dye from aqueous solutions. The batch biosorption experiments were carried out at various pH, biosorbent dosage, contact time and temperature. Optimum decolorization was observed at pH 2.0 and 1.6 g dm^− 3 of biomass dosage within 20 min. The first-order and the pseudo-second-order kinetics were investigated for the biosorption system. The applicability of the Langmuir and Freundlich isotherm models was examined. The thermodynamic parameters for the biosorption were also calculated. The experimental results in this study indicated that this low-cost biomaterial was an attractive candidate for the removal of textile dye Reactive Red 198 (RR198) from aqueous solutions.     

Photoelectro-peroxone process for the degradation of reactive azo dye in aqueous solution

ABSTRACT

This study evaluated the degradation of reactive yellow F3R (RY F3R) dye by photoelectro-peroxone (PEP) process. The study showed that the PEP gave 97.66% colour and 84.64% TOC removals at 1.176 h^?1 which were 14 and 1.4 times greater than photolysis and electro-peroxone processes, respectively. Quenching experiment showed that hydroxyl radical and singlet oxygen were predominant oxidizing species in RY F3R degradation. In addition, results of the colour and TOC removal by the application of PEP to real field textile wastewater showed that PEP offer an efficient and propitious technology for organic pollutant degradation.     

Decolorization of disperse and reactive dyes by continuous electrocoagulation process

The electrocoagulation process was developed to overcome the drawbacks of conventional wastewater treatment technologies. This process is very effective in removing organic pollutants including dyestuff wastewater and allows for the reduction of sludge generation. The purposes of this study were to investigate the effects of the operating parameters, such as current density, electrode number, electrolyte concentration, electrode gap, dyestuff concentration, pH of solution and inlet flow rate, on decolorization by continuous electrocoagulation. The dye removal efficiencies and reaction rate constants from the curves following the first-order relationship of electrocoagulation were calculated. In addition, from the points of power consumption, the effects of the operating parameters were also searched. Finally, the behaviors of decolorization according to dyestuff types, i.e., disperse dye and reactive dye, were also examined.     

Surface characterization and Remazol Red adsorption by asymmetric polyethersulfone membranes modified by polyelectrolyte complexes

Polyethersulfone (PES) membranes containing 4-fluorophenyl sulfone-terminated poly(diallylpiperidinium hexafluorophosphate)-sulfonated poly(ethylene terephthalate) polyelectrolyte complexes (PECs) were obtained via phase inversion using three different methods that enabled the complexation of polyelectrolytes (PELs) to occur before, after, and during membrane formation. Atomic force microscopy-infrared spectroscopy analysis revealed varying concentrations of the polyanion depending on the preparation method and confirmed the presence of PECs in the membranes, highlighting an increase in surface roughness. Zeta potential measurements demonstrated positive surface charges for the membrane comprising PES and the polycation. The reduction in zeta potential in PEC membranes corresponded with the neutralization of positive groups by sulfonated poly(ethylene terephthalate. Scanning electron microscopy micrographs depicted surface imperfections in PEC membranes, emphasizing the influence of PECs on membrane surfaces. The water contact angle decreased, indicating increased hydrophilicity in PEC membranes. Additionally, dye adsorption results showcased significant adsorption, with the membranes absorbing at least 60% of Remazol Red from an aqueous solution. Notably, the Blend membrane outperformed others, exhibiting an exceptional adsorption rate exceeding 92%.     

Removal of Remazol Brilliant Blue R dye from aqueous solutions by adsorption onto immobilized Scenedesmus quadricauda: Equilibrium and kinetic modeling studies

The green algae Scenedesmus quadricauda was immobilized in alginate gel beads. The immobilized active (IASq) and heat inactivated S.quadricauda (IHISq) were used for the removal of Remazol Brilliant Blue R (CI 61200, Reactive Blue 19, RBBR) from aqueous solutions in the concentration range 25-200 mg L^− 1. At 150 mg L^− 1 initial dye concentration the IASq and IHISq exhibited the highest dye uptake capacity at 30 °C, at the initial pH value of 2.0. At the same initial dye concentration in the batch system the adsorption capacity was determined for IASq as 44.2; 44.9 and 45.7 mg g^− 1 in 30, 60 and 300 min, respectively. After 300 min the adsorption capacity hardly changed during the adsorption time. The IHISq of adsorption capacity was observed as 47.6; 47.8 and 48.3 mg g^− 1 in 30, 60 and 300 min, respectively. After 300 min the adsorption capacity was not changed for 24 h. The Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Flory-Huggins isotherm models were used to fit the equilibrium biosorption data. The Langmuir, Freundlich and Dubinin-Radushkevich equations have better coefficients than Temkin and Flory-Huggins equation describing the RBBR dye adsorption onto IASq and IHISq. The monomolecular biosorption capacity of the biomass was found to be 68 and 95.2 mg g^− 1 for IASq and IHISq, respectively. From the Dubinin-Radushkevich model, the mean free energy was calculated as 6.42-7.15 kJ mol^− 1 for IASq and IHISq, indicating that the biosorption of dye was taken place in physical adsorption reactions. The experimental data were also tested in terms of kinetic characteristics and it was determined that the biosorption process of dye was well explained with pseudo-second-order kinetics.     

Removal of acid blue 113 and reactive black 5 dye from aqueous solutions by activated red mud

Removal of acid blue 113 (AB113) and reactive black 5 (RB5) dyes from aqueous solutions by activated red mud was investigated at different reaction parameters. Activated red mud has higher removal efficiency for AB113 than that for RB5. This can be explained by a greater molecular size of RB5 than that of AB113 and by different binding affinity with the surface of the activated red mud. Equilibrium data was fitted well with Freundlich isotherm and the kinetic data followed a pseudo second-order model. Maximum adsorption capacity was 83.33 mg/g and 35.58 mg/g at pH 3 for AB113 and RB5, respectively.     

Mass-producible low-cost flexible electronic fabrics for azo dye wastewater treatment by electrocoagulation

Electrocoagulation is progressively becoming an ecologically friendly water treatment method owing to its lack of secondary pollution,high active ingredient concentration,high treatment effectiveness,simple equipment,and simplicity of automated control implementation.Herein,electrocoagulation is offered as a method for treating wastewater containing azo dyes using a revolutionary flexible electronic fabric that can be mass-producible at a reasonable price.A computer-controlled machine embroiders...     

Degradation of azo dye C.I. Acid Red 18 in aqueous solution by ozone-electrolysis process

In this paper, the degradation of azo dye C.I. Acid Red 18 (AR18) with initial concentration of 100 mg L⁻¹ in aqueous solution by ozone-electrolysis process (OEP) as hybrid method of advance oxidation process was investigated. All experiments were performed in a 450 mL mixed semi-batch reactor to obtain the optimal conditions. The effects of NaCl concentration as supporting electrolyte, current density and initial pH on the removal efficiency of AR18 solution were investigated. The efficiency of color and TOC removal were compared as functional of degradation and decolorization of AR18. The results of UV/vis spectra showed that the AR18 structures were destroyed under ozone-electrolysis reaction. This investigation revealed ozone-electrolysis presents good efficiency for both solution decolorization and total organic carbon (TOC) removal. Results of experiments indicated that ozone-electrolysis process has a synergistic effect on decolorization rate of AR18.     

Decolorisation optimisation of a monoazo disperse dye with Bacillus firmus. Identification of a degradation product

Decolorisation of a heterocyclic monoazo red disperse dye by a bacterial strain Bacillus firmus isolated from local sewage and grown in mineral salt medium (MSM) was investigated. The effect of nutritional as well as environmental factors on the decolorisation efficiency was studied. Aerobic shaking (100 rpm) of a monoazo disperse dye, at pH 6.0, with the strain cultivated after 48 h, resulted in extensive (95–98%) decolorisation at 35 °C, whereas under anoxic conditions, decolorisation was only 75%. The nutrients sucrose (0.125% w/v), ammonium sulphate (0.05% w/v) and yeast extract (0.0025% w/v) have been found to be effective in decolorisation of the dye. One of the degradation products could be isolated and characterised using chromatographic and spectroscopic techniques.