Decolorization Of Dye Solution Research Articles

Kinetic and equilibrium studies of adsorption of acid blue dye onto preformed flocs as adsorbents

AbstractAdsorption studies of decolorization of Acid blue dye by using novel adsorbents of preformed flocs of Aluminum Sulphate, Ferric Chloride, and Ferrous Sulphate were carried out through non‐flow batch sorption studies. The influence of pH, equilibrium contact time, and floc dose on color removal was studied. Kinetic and equilibrium studies were carried out to know the efficacy of adsorbents in the decolorization of an aqueous solution of C.I. Acid blue 113 dye. In order to probe into the mechanism involved in the decolorization of dye solution, FTIR and SEM studies were conducted. The Langmuir isotherm was well fitted to the equilibrium data implying that there is monolayer formation in the process of sorption. Kinetic data fitted well to pseudo second order which states that chemisorption is the rate limiting step in the adsorption process. The adsorption capacity of preformed flocs of aluminum sulphate, ferric chloride, and ferrous sulphate were found to be 450 mg/g, 500 mg/g, and 125 mg/g. FTIR and SEM studies shows that there is adsorbent‐dye complex formation in the adsorption process of decolorization of Acid dye with preformed flocs.

Decolorization of dye solution containing Remazol Black B by Aspergillus niger isolated from hypersaline environment

Decolorization of dye solution containing Remazol Black B by Aspergillus niger isolated from hypersaline environment

Decomposition performance of hypochlorite on bead-type NiOx(OH)y catalyst: improving applicability of catalysts.

An easy-to-use, pollution-free and reusable beaded NiOx(OH)y catalyst for improving hypochlorite oxidation was prepared by impregnating the mixture of persulfate and alkali over alumina and then reduced it with Ni2+. The effects of catalyst preparation conditions and reaction parameters on NaClO conversion rate and Ni2+ dissolution rate were studied. Impregnating the γ-Al2O3 beads in PS/OH- mixed solution with 0.59 M PS and PS/OH- molar ratio of 1.1, and then reducing with 0.8 M Ni2+ solution is the best condition for preparing catalyst. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The best catalytic layer is characterized by high content of chemisorbed oxygen which can be converted into atomic oxygen. The hypochlorite conversion rate increased with the catalyst dosage and reuse times, and decreased with available chlorine, while pH of hypochlorite solution had little effect on the conversion rate. After running stably for 120 h in continuous flow test, the chemisorbed oxygen content in the optimal catalytic layer decreased slightly. Atomic oxygen plays an important role in the decolorization of dye solution by NaClO/NiOx(OH)y system. The oxidant consumption cost of this process is much cheaper than Fenton reagent. The prepared catalyst has great potential in hypochlorite decomposition and wastewater treatment.

Presentation of different cellulosic yarn spinning wastes for decolorization of a basic dye solution

Waste management and reuse have now become the trend topics because of the demand to the comfortable survival of human being. For the cleaner production these two approaches have of great importance. Waste management and reuse consists many activities containing production and consumption of the goods and services. Here in this study, the wastes from a cotton yarn spinning line (mostly containing cotton fibers, seed coats etc.) were collected and characterized then they were used in decolorization of a dye solution containing a cationic (basic) dye. Before using the wastes, the wastes were dried at different temperatures for different durations, and these wastes were used as dye-adsorbing materials, such as those not previously treated with heat. As a result, it was determined that the adsorbents constituted of the spinning mill wastes had the ability to adsorb the dye from the dye solution. It has also been found that the heat pretreatment has an effect on the color removal efficiency of the wastes. By this way, it has been tried to introduce a process that uses waste from the spinning mill to remove the color of textile dye wastes containing basic dyes.

Decolorization of dye solutions by tyrosinase in enzymatic membrane reactors

AbstractBACKGROUNDThe main aim of this study was to investigate the decolorization performance of enzymatic membrane reactors (EMRs) using tyrosinase, including direct contact membrane reactor (DCMR) and immobilized enzyme membrane reactor (IEMR). The crosslinked polyacrylonitrile (PAN)/chitosan composite membrane was employed in a separation unit as support for tyrosinase immobilization to decolorize two common Acid Blue 113 (AB113) and Direct Black 22 (DB22) azo dyes for the first time.RESULTSAccording to the obtained results, the optimum enzyme amount, which could be immobilized on the membrane surface, was 25 units. The proper operating conditions for both DCMR and IEMR were determined as pH 6.5 and temperature 30 °C. Both the reactors initially accounted for around 96% and 94% decolorization for AB113 and DB22, respectively. To determine the reusability of EMRs after 10 cycles, 83.1% and 78.5% dye removal were achieved using IEMR for AB133 and DB22, respectively; while for DCMR, this amount reduced to 60.5% and 58.3% for AB113 and DB22, respectively.CONCLUSIONThe proposed IEMR maintained a high dye removal amount through the studied pH and temperature ranges. However, the performance of DCMR considerably reduced under the intensive operating conditions as well as in the long‐term operation. As a result, the suggested immobilized enzyme showed superior and stable performance compared to the free one in the long‐term operation. © 2019 Society of Chemical Industry

Saturated Resin Ectopic Regeneration by Non-Thermal Dielectric Barrier Discharge Plasma

Textile dyes are some of the most refractory organic compounds in the environment due to their complex and various structure. An integrated resin adsorption/Dielectric Barrier Discharge (DBD) plasma regeneration was proposed to treat the indigo carmine solution. It is the first time to report ectopic regeneration of the saturated resins by non-thermal Dielectric Barrier Discharge. The adsorption/desorption efficiency, surface functional groups, structural properties, regeneration efficiency, and the intermediate products between gas and liquid phase before and after treatment were investigated. The results showed that DBD plasma could maintain the efficient adsorption performance of resins while degrading the indigo carmine adsorbed by resins. The degradation rate of indigo carmine reached 88% and the regeneration efficiency (RE) can be maintained above 85% after multi-successive regeneration cycles. The indigo carmine contaminants were decomposed by a variety of reactive radicals leading to fracture of exocyclic C=C bond, which could cause decoloration of dye solution. Based on above results, a possible degradation pathway for the indigo carmine by resin adsorption/DBD plasma treatment was proposed.

Enhanced Performance of Magnetic Graphene Oxide-Immobilized Laccase and Its Application for the Decolorization of Dyes.

In this study, magnetic graphene oxide (MGO) nanomaterials were synthesized based on covalent binding of amino Fe3O4 nanoparticles onto the graphene oxide (GO), and the prepared MGO was successfully applied as support for the immobilization of laccase. The MGO-laccase was characterized by transmission electron microscopy (TEM) and a vibrating sample magnetometer (VSM). Compared with free laccase, the MGO-laccase exhibited better pH and thermal stabilities. The optimum pH and temperature were confirmed as pH 3.0 and 35 °C. Moreover, the MGO-laccase exhibited sufficient magnetic response and satisfied reusability after being retained by magnetic separation. The MGO-laccase maintained 59.8% activity after ten uses. MGO-laccase were finally utilized in the decolorization of dye solutions and the decolorization rate of crystal violet (CV), malachite green (MG), and brilliant green (BG) reached 94.7% of CV, 95.6% of MG, and 91.4% of BG respectively. The experimental results indicated the MGO-laccase nanomaterials had a good catalysis ability to decolorize dyes in aqueous solution. Compared with the free enzyme, the employment of MGO as enzyme immobilization support could efficiently enhance the availability and facilitate the application of laccase.

Preparation and characterization of microfiltration apatite membrane over low cost clay-alumina support for decolorization of dye solution

AbstractApatite material obtained from natural sources of Tunisian mineral has been used for the development of membrane over clay–alumina-based microporous supports. For this purpose, supports of single-channel and 19-channel circular configurations were used. The apatite powder used for membrane preparation had average pore diameter of 4.02 μm. Coating formulation has been optimized to obtain stable suspension. Powder loading of 4 wt.% was found as optimum for obtaining a proper microfiltration membrane with 0.2 μm pore diameter. Single-channel membrane was used for characterization. The application to color removal from synthetic reactive dye solution was performed using membrane with 19-channel configuration. An average water flux of 200 and 80 l/m2 h was obtained for 19-channel support and membrane, respectively, in laboratory scale setup. Reactive red dye removal from synthetic dyeing solution was achieved up to 99%. Resulting saturated membrane was successfully regenerated using H2O2 at various con...

Decolorization of dyes with different molecular properties using free and immobilized laccases from Trametes versicolor

Laccases from Trametes versicolor have been used for the decolorization of acid and reactive dye solutions. The dyes considered were the acid orange 7 (AO7), acid blue 74 (AB74), reactive red 2 (RR2) and reactive black 5 (RB5). The decolorization of dye solutions was performed in batch systems under constant agitation at 30°C, using both free laccases and laccases immobilized on a mesoporous carbon obtained from pecan shells. Results obtained pointed out that the biocatalysts tested are more effective in the decolorization of acid dyes (AO7 and AB74), with more than 90% of decolorization percentages attained, than reactive dyes. Furthermore, the laccase used in this study, either freely dissolved or supported on the carbon materials, was inactive towards RB5, which was the larger dye molecule (992gmol−1). Immobilization of the laccase on the mesoporous carbons brought about a considerable decrease of their activity. However, an enzyme stabilization effect was also observed as the activity of the supported laccase was maintained over a wide pH span. Finally, the combination of spectrophotometric and chromatographic (HPLC) techniques allowed us to get a more precise picture of the influence of adsorption/oxidation mechanisms during the degradation of dyes by the supported enzymes.

Production and characterization of bioflocculants for mineral processing applications

A comparative study of two bacterial strains namely, Bacillus licheniformis and Bacillus firmus in the production of bioflocculants was made. The highest bioflocculant yield of 16.55g/L was obtained from B.licheniformis (L) and 10g/L from B.firmus (F). The bioflocculants obtained from the bacterial species were water soluble and insoluble in organic solvents. FTIR spectral analysis revealed the presence of hydroxyl, carboxyl and sugar derivatives in the bioflocculants. Thermal characterization by differential scanning calorimetry (DSC) showed the crystalline transition and the melting point (Tm) at 90-100°C. Effects of bioflocculant dosage and pH on the flocculation of clay fines were evaluated. Highest bioflocculation efficiency on kaolin clay suspensions was observed at an optimum bioflocculant dosage of 5g/L. The optimum pH range for the maximum bioflocculation was at pH7–9. Bioflocculants exhibited high efficiency in dye decolorization. The maximum Cr (VI) removal was found to be 85% for L (bioflocculant dosage at 2g/L). This study demonstrates that microbial bioflocculants find potential applications in mineral processing such as selective flocculation of mineral fines, decolorization of dye solutions and in the remediation of toxic metal solutions.

Metal-ceramic composites prepared under combustion conditions and their catalytic activity in dye degradation

Composites based on boron, silicon, and chromium nitrides and on Sialon were prepared with the aim of using them in photocatalytic degradation of dyes for wastewater treatment. The surface parameters, elemental and phase composition, and morphology and size of particles of the materials were evaluated. The activity of the composites in decolorization of dye solutions under the conditions of generation of photoactive systems (Ruff-Fenton, ferrioxalate, peroxide-ferrioxalate) was studied. The highest degree of dye degradation is reached when using composites based on boron nitride, which is due to the combination of the photoadsorption and photooxidation.

Behavior of dihydroxybenzenes and gallic acid on the Fenton-based decolorization of dyes

AbstractDihydroxybenzenes (DHBs) are used as mediators to increase the degradation of recalcitrant organic pollutants by Fenton reaction. DHBs regenerate Fe2+ ions, resulting in the formation of OH radicals in a more intense and continuous manner than the classical Fenton reaction. The present work investigates the behavior of different DHBs and gallic acid (a trihydroxybenzene) on the decolorization of dye solutions by Fenton systems (Fe2+/H2O2, Fe3+/H2O2). For the majority of DHBs and gallic acid, pro-oxidant properties were observed on the decolorization of methylene blue, chromotrope 2R, methyl orange, and phenol red. These properties were dependent on the hydroxyl position in the aromatic ring and were highly influenced by the structure and redox potential of the target pollutant. The dye decolorization by Fenton-like reaction (Fe3+/H2O2) in the presence of 2,5-dihydroxybenzoic acid as mediator was more efficient than classical Fenton reaction. For example, Fe3+/H2O2/2,5-dihydroxybenzoic acid system ...

BIOTRANSFORMATION OF TEXTILE DYES: A BIOREMEDIAL ASPECT OF MARINE ENVIRONMENT

Presence of huge amount of salts in the wastewater of textile dyeing industry is one of the major limi ting factors in the development of an effective biotreat ment system for the removal of dyes from textile effluents. Large number of textile industries are l ocated on the coastal areas due to ease of transpor t to the various places in world and help in building na tions economy, but on the contrary the effluents released from these industries are proving a great problem for the marine life. Therefore, industrial effluents containing dyes must be treated before th eir safe discharge into the environment. There are various physiochemical methods are conventionally used. These methods are effective but quite expensive leading to the production of solid sludge . Bacterial spp. capable of thriving under high sal t conditions could be employed for the treatment of s aline dye-contaminated textile wastewaters. Most of the Scientists used chemical coagulation, Flocculat ion and Precipitation techniques for the removal of dye colors from waste waters. But this method is no t cost beneficial as it generates huge amount of Sludge and to dispose the sludge is major problem. The physical methods are also not cost effective. S o only biological treatment using acclimatized microo rganisms could remove 99-100% dye colour from wastewater. Hence now a day most of the workers concentrated on biotransformation of textile azo dyes by adapted organisms. The use of co substrates also slightly increased the decolorization of dye solut ion. Some scientists showed that the products of dye deg radation are not toxic to biological system. Produc ts formed can be determined by Gas Chromatography and Mass Spectroscopy (GC-MS) technique, Fourier Transform Infra Red (FTIR) etc.

Decolorization of dye solutions with Ruditapes philippinarum conglutination mud and the isolated bacteria

Application of Ruditapes Philippinarum conglutination mud (RPM) for decolorizing synthetic dye solutions was studied. RPM showed good activity for decolorization of Methylene Blue, Crystal Violet, Malachite Green, and Ink Blue. The amount of the RPM had great effect on the decoloration rate of the dye solutions. However, the decoloration rate did not continue to increase when the amount of mud exceeded the optimum dose. The temperature of the dye solution had a remarkable effect on the decolorization rate of Ink Blue solution, but had little effect on the other three dye solutions. The initial pH of the dye solutions evidently affected the decolorization rate of Malachite Green solution, but had less effect on the other three. The decolorization rate of the dye solutions increased significantly with treatment time within 8 hr, but tended to be steady after 8 hr for Methylene Blue, Crystal Violet and Malachite Green solutions, and after 12 hr for Ink Blue solution. The decolorization efficiencies for the four dye solutions under the optimum conditions were all above 90%. Seventeen strains screened from RPM showed flocculation ability for kaolin clay suspension. Out of them, the flocculation rate of strain ZHT3-9 and strain ZHT4-13 were up to 88.14% and 86.01%, respectively. ZHT3-9 was studied, and its decolorization rate for Methylene Blue, Crystal Violet, and Malachite Green reached 90.02%, 89.21%, and 80.29%, respectively. By morphological, physiological and biochemical characteristics analysis and 16S rRNA sequencing, the strain ZHT3-9 was identified as Arthrobacter sp.

Amorphous titanium dioxide: a recyclable dye remover for water treatment

Decolorization of dye solutions, crystal violet and congo red, were investigated using the synthesized amorphous titanium dioxide and compared with commercial titanium dioxides: Degussa P25 and anatase. Results showed that amorphous TiO2 had good adsorptivity that could decolorize the dye polluted water effectively mainly by adsorption. Decolorization by photocatalytic property was also detected but was very low. Concentrations of dye solutions used in this work were about ten times higher than normally used in other reports. After use, the particle surface was completely covered with dye molecules but this could be regenerated and the cleaned particles could be reused several times. Hydrogen peroxide and ultraviolet irradiation were used in the regeneration process.

Effect of continuous addition of H2O2 and air injection on ferrioxalate-assisted solar photo-Fenton degradation of Orange II

An experimental study based on ferrioxalate-assisted solar photo-Fenton (SPFox) process shows how non-biodegradable azo dye Orange II (OII) solutions degradation can be enhanced or slowed down by continuous addition of hydrogen peroxide and air injection depending on operation conditions. The decoloration and mineralization of dye solution has been carried out in a solar Compound Parabolic Collector (CPC). An optimization study was done by using Multivariate Experimental Design including the following variables: flow rate of H2O2, air flow rate, pH and initial concentrations of Fe(II) and oxalic acid. The efficiency of photocatalytic degradation was determined from the analysis of color and Total Organic Carbon (TOC). Experimental data were fitted using neural networks (NNs) which allow the simulation of the process for any value of variables in the studied experimental range. The results reveal that the continuous addition of H2O2 improves the photocatalytic efficiency since the scavenger effect of peroxide is minimized. On the other hand, this system permits the use of a ferrous concentration below the discharge legal limit (2ppm) being bubbling of air not necessary in that conditions. In addition, oxalic acid can be used to pH adjustment, reducing the operation costs of Fe removal, chemicals and electric power. Under the optimal conditions, 100% decoloration of dye solution can be reached by using both processes (SPFox with H2O2 addition at the beginning or along the reaction) but with different reaction rates. However, the efficiency of TOC removal was higher in the SPFox process with continuous addition of H2O2 (95% TOC removal in SPFox system with continuous addition of peroxide versus 80% TOC removal in SPFox system when peroxide is added at the beginning of the reaction). Molecular and/or radical reaction pathway was studied by conducting the reaction in the presence and absence of tert-butylalcohol.

Homogeneus ferrioxalate-assisted solar photo-Fenton degradation of Orange II aqueous solutions

The decoloration and mineralization of the non-biodegradable azo dye Orange II (OII) solutions by solar photo-Fenton (SPF) and ferrioxalate-assisted solar photo-Fenton (SPFox) reactions have been carried out in a solar compound parabolic collector (CPC). A comparative study of these two processes was done by using multivariate experimental design including the following variables: pH and initial concentrations of Fe(II), oxalic acid, H2O2 and OII. The efficiency of photocatalytic degradation was determined from the analysis of the following parameters: color, total organic carbon (TOC) and chemical oxygen demand (COD). The decoloration rate pseudoconstant was calculated as a function of the accumulated solar energy received by the water solution. Experimental data were fitted using neural networks (NNs) which reproduce the results within 85% of confidence and allow the simulation of the process for any value of variables in the experimental range studied. The results reveal that the addition of oxalic acid to the Fenton system (Fe(II)/H2O2) irradiated under sunlight improves the photocatalytic efficiency since ferrioxalate complexes absorb strongly and a higher portion of the solar spectrum can be used. In addition, the SPFox system permits the use of an iron concentration below the discharge legal limit (2ppm) and oxalic acid can be used to pH adjustment, reducing the operation costs of Fe removal and chemicals. Under the optimal conditions, 100% decoloration of dye solution can be reached by using both processes, but with different accumulated solar energy (SPF system: 34Wh, SPFox system: 16Wh). However, the efficiency of TOC and COD removal was higher in the SPFox process (80% TOC and 100% COD removal in SPFox system versus 50% TOC and 80% COD removal in SPF system).

Electrocoagulation of methylene blue and eosin yellowish using mild steel electrodes

The paper presents the study of electrocoagulation (EC) of aqueous dye solutions of two different industrial dyes in a batch stirred cell. Experiments were carried out with 200 mg/l individual concentration of methylene blue (MB) and eosin yellowish (EY) in presence of NaCl as electrolyte. Effect of operating time and current density on the decolorization of dye solutions, reduction of chemical oxygen demand (COD) and variation in conductivity, pH during treatment has been studied. Small difference between color diminution and COD reduction has been found with the progress of treatment. First-order rate equation for dye removal has been developed from the experimental results. Sludge formation during EC and problems associated with this solid waste generation and disposal has been assessed. Energy consumption in KWh/m 3 with reduction of COD (kg) during treatment has been reported. Electric power consumption of 1.5 KWh reduces 0.21 and 0.11 kg COD from 0.24 and 0.14 kg of initial COD for MB and EY, respectively, starting from 200 mg/l dye concentration.

Decolorization of dye solutions by a membrane bioreactor (MBR) using white-rot fungi

In this study a membrane bioreactor (MBR) using white-rot fungi was used for the decolorization of dye solutions. The decolorization of dye solutions by Trametes versicolor KCTC 16781 and membrane filtration were combined, and the applicability of this process was investigated using reactive dye solutions. The feasibility of MBR using fungal biodegradation was studied with nanofiltration and reverse osmosis (RO) membranes to improve permeate flux and separation efficiencies. The effects of dye types on fungal biodegradation and membrane filtration (permeate flux and rejection) were also investigated. The fungal MBR combined with RO was found effective for decolorization and organic removal of dye wastewater.

Decolorization of dye solution containing Acid Red 14 by electrocoagulation with a comparative investigation of different electrode connections

This study was performed to investigate the variables that influence the efficiency of decolorization of a solution containing an azo dye (Acid Red 14) by electrocoagulation (EC) in order to compare the efficiency of different electrode connections for color removal. Current density, time of electrolysis, interelectrode distance, and pH of the solution were the variables that most influenced color removal. Initially, a simple electrochemical cell was prepared with an anode and a cathode. Then the effect of each variable was studied separately using synthetic wastewater in a batch mode. The efficiency of the method tested was determined by measurement of color removal and reduction of Chemical Oxygen Demand (COD). For dye solutions with COD of approximately 30 ppm and dye concentrations less than 150 ppm, high color removal (93%) was obtained when the pH ranged from 6 to 9, time of electrolysis was approximately 4 min, current density was approximately 80 A/m 2, the temperature was approximately 300 K, and interelectrode distance was 1 cm. During the EC process under these conditions, the COD decreased by more than 85%. In the second series of experiment, the efficiency of EC cells with monopolar electrodes in series and parallel connections and an EC cell with bipolar electrodes were compared with results using a simple electrochemical cell. The experimental results showed that an EC cell with several electrodes was more effective than a simple electrochemical cell in color removal. The results also showed that an EC cell with monopolar electrodes had a higher color removal efficiency than an EC cell with bipolar electrodes. Furthermore, within an EC cell, the series connection of the monopolar electrodes was more effective for the treatment process than the parallel connection in color removal.