Direct Violet Research Articles

Removal of Anionic Direct Dye Using Zn/Al, Zn/Fe and Zn/Cr Layered Double Hydroxides Toward Interlayer Distance

In order to minimize harmful effect of synthetic dye (direct yellow and direct violet) the capacity of Zn/Al, Zn/Cr and Zn/Fe layered double hydroxides of these contaminant was studied in this work. Batch adsorption experiment was conduct to investigate the effect of various operating parameters such as contact time, initial dye concentration and adsorption temperature in order to provide optimal condition in removal synthetic dye. Based on result, the sorption of direct dye onto LDHs followed pseudo-second-order rate model. The equilibrium adsorption data for both direct dye was fitted Freundlich isotherm model

The influence of titanium dioxide nanofiller ratio on morphology and surface properties of TiO2/chitosan nanocomposite

Abstract In the present study, different ratios of TiO2-chitosan nanocomposite (nT-CS) [1:1(nT-CS1), 1:2 (nT-CS2), and 1:5 (nT-CS5)] were prepared by using the method of solution blending. The characterization of the prepared nanocomposite was done through different techniques such as Fourier transform Infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM), and surface area analysis (BET, BJH). The results of FTIR and Raman spectroscopy indicate the appearance and the shifting of main bands of titanium dioxide and chitosan. In addition, the XRD results show shifting of main bands and change in crystal structure of chitosan. The images of AFM and SEM indicate that the TiO2 nanoparticles homogenously distributed throughout the chitosan matrix with an appearance of some agglomeration. The BET analysis indicates that nanocomposite with ratio 1:2 (nT-CS2) had the highest surface area 113 m2/g. Besides that, this ratio showed high adsorption of Direct Violet 51 (DV51) from its aqueous solutions.

Sonophotocatalytic degradation of aqueous Acid Red 27 and Direct Violet 51 using copper impregnated Al2O3

Sonophotocatalytic degradation of aqueous Acid Red 27 and Direct Violet 51 using copper impregnated Al2O3

Kinetics and mechanism of the oxidative decolorization of direct violet 31 in the presence of peroxodisulfate-silver(I) as a redox system

The redox decolorization of direct violet 31 [DV-31]− by Ag(I)/S2O82− under conditions similar to the Fenton process was studied kinetically in aqueous solution over a range of different concentrations of dye and redox system. The oxidation rate increases with decreasing pH. The reaction is catalyzed by Ag(I) through the formation of Ag(II) which is a very strong oxidizing agent. A tentative mechanism for silver(I) catalyzed oxidation of [DV-31]− by peroxydisulfate is proposed. Pseudo-order conditions were maintained in all experiments by using an excess of S2O82− (> 10-fold). The reaction obeys the following rate law: $$ {\text{Rate}} = \left( {K_{1} K_{2} k_{5} \left[ {H^{ + } } \right] + K_{3} k_{6} } \right)\left[ {{\text{Ag}}^{ + } } \right]\left[ {{\text{S}}_{2} {\text{O}}_{8}^{2 - } } \right] $$ The magnitudes of the thermodynamic activation parameters suggest that electron transfer proceeds through an outer-sphere mechanism. Sodium dodecylsulfate (SDS) was found to decrease the rate of reaction due to attraction of the Ag(I) ion into the SDS pseudo-phase, leaving other reactants in the bulk solution. Additionally, 1H NMR spectra of [DV-31]− before and after degradation confirmed almost complete mineralization of the dye.

Haererehalobacter sp. JS1, a bioemulsifier producing halophilic bacterium isolated from Indian solar salt works.

Bioemulsifier (BE)-producing Haererehalobacter sp. JS1 was isolated and identified from the solar salt works in India. The BE was extracted, purified, and characterized by Gas Chromatography-Mass Spectrometry (GC-MS) analysis. Emulsification activity was performed against different oils and dye degradation potential against different dyes. The production of BE was optimized using different carbon sources (C), nitrogen sources (N), pH, and NaCl. BE screening methods revealed that, Haererehalobacter sp. JS1 was highly positive BE production. Identification by 16S rRNA sequencing and analyses was found that, the Haererehalobacter sp. JS1 was closely related to Salinicoccus halophilus and Haererehalobacter sp. The structural characterization analysis confirmed that the partially purified bioemulsifier belongs to siloxane-type. Emulsification activity (E24) revealed that the bioemulsifier significantly (p < = 0.001) emulsified the commercial oils including coconut oil, gingelly oil, olive oil, and palmolein oils. Haererehalobacter sp. JS1 also significantly (p < = 0.001) degraded the dyes such as orange MR, direct violet, cotton red, reactive yellow, nitro green, and azo dye. RSM regression co-efficient and contour plot analysis clearly indicated that the combination of pH and NaCl helped to increase BE production. Siloxane-type of BE obtained from Haererehalobacter sp. JS1 was able to emulsify different oils and commercial dyes.

Recycling food waste to clean water: the use of a biodigester's residual liquid inoculum (RLI) to decolourise textile azo dyes.

A residual liquid inoculum (RLI) was used to decolourise solutions of Acid Yellow 25 (AY25) and Direct Violet 51 (DV51) azo dyes. The RLI was obtained through anaerobic digestion of food waste from a university restaurant. The concentration of bacteria in the RLI was 8.45 × 107 CFU mL-1. Dye solutions (50 μg mL-1) were inoculated with the RLI (20% v/v) and incubated at room temperature. The decolourisation studies took place at microaerophilic and in-batch conditions and at pH = 2.50. Initially, the dyes were taken up from solution by biosorption; maximum colour removal was achieved after 3 hours of incubation, with 88.66% for AY25 and 77.65% of DV51. At prolonged incubation times (3-96 hours) decolourisation was mainly attributed to biodegradation of the azo solutions, with breakage of the azo bond, as detected by UV-VIS spectroscopy and Fourier transform infrared (FT-IR) analysis. Analysis of UV-VIS absorption rates of dyes showed, however, that AY25 was more readily biodegradable whereas DV51 was more recalcitrant to the action of the RLI.

Optimization of conditions for decolorization of azo-based textile dyes by multiple fungal species

Wastewater from textile industries contains azo dye residues that negatively affect most environmental systems. The biological treatment of these wastes is the best option due to safety and cost concerns. Here we isolated and identified 19 azo dye-degrading fungi and optimized conditions resulting in enhanced degradation. The fungi belonged to five species of Aspergillus and a single Lichtheimia sp. All fungi were evaluated for their ability to decolorize 20 azo dyes. While the most easily transformable azo dye was direct violet (decolorization ranged from 71.1 to 93.3%), the most resistant to decolorization was fast green azo dye. The greatest degradation potential of azo dyes (direct violet and methyl red) was optimized using the most promising four fungal strains and changing media glucose concentration, nitrogen source, and micronutrients. Biomass, lignin peroxidase, and laccases production were also determined in the optimization studies. The decolorization of both azo dyes by the four fungal strains was greatly enhanced by glucose supplementation. The fungal strains were not able to produce lignin peroxidases in the absence of organic nitrogen source. Both yeast extract and casamino acid supplementation enhanced decolorization of direct violet and methyl red dyes and production of lignin peroxidase by the fungal strains. In contrast, the laccases were absent in the similar medium enriched with the same organic nitrogen sources.

Preparation and catalytic performance of copper-containing magnetic catalysts for degradation of azo dye (direct violet).

A novel magnetically separable magnetic activated carbon supporting-copper (MCAC) catalyst for catalytic wet peroxide oxidation (CWPO) was prepared by chemical impregnation. The prepared samples were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, and scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS). The catalytic performance of the catalysts was evaluated by direct violet (D-BL) degradation in CWPO experiments. The influence of preparative and operational parameters (dipping conditions, calcination temperature, catalyst loading H2O2 dosage, pH, reaction temperature, additive salt ions and initial D-BL concentration) on degradation performance of CWPO process was investigated. The resulting MCAC catalyst showed higher reusability in direct violet oxidation than the magnetic activated carbon (MAC). Besides, dynamic tests also showed the maximal degradation rate reached 90.16% and its general decoloring ability of MCAC was 34 mg g-1 for aqueous D-BL.

Kinetic and equilibrium studies of decolorization of effluent of handmade paper industry by low-cost fly ash

Handmade paper is famous for its bright color made by single dye or admixture of dyes. Handmade paper industry emits colored effluent which requires cost-effective treatment technologies. In the scope of the present paper, studies have been conducted with a simulated dye solution having a mixture of dyes being used in the handmade paper industry. The original fly ash and adsorbed fly ash were characterized for SEM-EDX, XRD, and Fourier transform infrared (FTIR) studies. The FTIR studies of direct dyes used in mixture (direct orange, direct navy blue, and direct violet dye) were conducted. The batch studies were conducted with low-cost fly ash and various affecting parameters, i.e. pH, initial concentration, temperature of the dye solution, dosage, and particle size of fly ash. The maximum adsorption capacity of fly ash was found to be 120.48 mg/g with fly ash dosage of 40 g/L having particle size of 45–75μm with dye solution at pH 2 and 40°C temperature. The better coefficient value of R2 showed better fitting of the Langmuir isotherm with the experimental data. The kinetic sorption data are well represented by the pseudo-second-order kinetics for the entire sorption period. The change in enthalpy, entropy, and free energy were evaluated which indicated that the sorption process is endothermic, spontaneous, and feasible. The characteristics of the effluent of handmade paper industry after fly ash treatment in batch study confirm the acceptability of the use of fly ash for treatment of effluent of handmade paper industry.

Box–Behnken design optimization for the removal of Direct Violet 51 dye from aqueous solution using lignocellulosic waste

The present research work was designed to explore the biosorption efficiency of sugarcane bagasse (SB) biomass for the removal of Direct Violet 51 dye from aqueous solution. The modification of SB biomass was carried out by different physical and chemical treatments. HCl-treated SB biomass depicted maximum biosorption efficiency among all the modified SB biomasses. Box–Behnken experimental design was employed to illustrate the effect of three independent variables (initial dye concentration (A), biosorbent dose (B), and pH (C)) on the dye removal process. Maximum dye removal (63.0 mg g−1) was achieved at pH 2 and 0.05 g biosorbent dose. Higher initial dye concentration was found to be favorable for the dye removal process. Desorption study was conducted using NaOH solution of different strengths, and it was observed that 61.58% dye can be desorbed from the loaded biosorbent using 1 M NaOH solution. Characterization of SB biomass was also carried out by FTIR, scanning electron microscope, and TGA analysis. The results indicated that SB biomass can be used as an efficient biosorbent for the treatment of dye containing wastewater.

Functionalized Magnetic Microparticles for Fast and Efficient Removal of Textile Dyes from Aqueous Solution

The use of magnetic micro- and nanoparticles for the removal of pollutants from wastewater is gaining increasing attention. Here, amine-functionalized magnetic microparticles (AFMMs) and carboxylic-functionalized magnetic microparticles (CFMMs) were synthesized by modifying the surface of Fe3O4 with amino and carboxyl groups for fast and efficient removal of textile dyes from aqueous solution. The functionalized magnetic microparticles were characterized by TEM, SEM, FTIR, and VSM. The adsorption experiments were carried out by varying the regulating parameters like solution pH and adsorbent dosage and analyzed in terms of kinetic and isotherm models. It was demonstrated that simple electrostatic interactions between functionalized magnetic microparticles and adsorbates played a dominating role in the adsorption of textile dyes. The positively charged AFMMs adsorbed the negatively charged dyes vat blue (VB) and direct violet (DV) at pH 6 with the maximum removal percentages of 95.72 and 97.29 %, respectively. The maximum removal percentages of cationic dyes methylene blue (MB) and azure A chloride (AA) on the negatively charged CFMMs were 92.28 and 92.22 % at pH 11, respectively. Moreover, the adsorbed dyes could be desorbed completely from the surface of CFMMs at a lower pH, and AFMMs also allowed rapid removal of VB and DV in different water samples. All the results in the present work demonstrated that the functionalized magnetic microparticles as efficient, magnetically separable adsorbents are attractive for the removal of dye pollutants.

Potential Use of Low-Cost Lignocellulosic Waste for the Removal of Direct Violet 51 from Aqueous Solution: Equilibrium and Breakthrough Studies

An efficient biosorbent, sugarcane bagasse was used in native, HCl-treated, and Na-alginate immobilized form for the removal of Direct Violet 51 dye from aqueous solutions. Batch study was performed to optimize important process parameters, such as pH, contact time, biosorbent dose, initial dye concentration, and temperature. Removal of Direct Violet 51 was found to be favorable at pH 2 with the biosorbent dose of 0.05 g. Biosorption process was found to be exothermic in nature. Maximum dye biosorption (39.6 mg/g) was achieved by using HCl-treated biomass. The pseudo-second-order kinetic and Langmuir adsorption isotherm models showed best fitness to the experimental data. Thermodynamic study was also performed to determine the feasibility of biosorption process. Continuous mode study was performed to optimize the important process parameters, such as bed height, flow rate, and initial dye concentration for maximum removal of Direct Violet 51 dye. The higher bed height, low flow rate, and high initial dye concentration were found to be the better conditions for maximum dye biosorption (17.28 mg/g). The linearized form of the Thomas model equation fitted well to the experimental data. The bed depth service time model was used to express the effect of bed height on breakthrough curves. Characterization of biosorbent was performed by scanning electron microscopy and Fourier transform infrared (FT-IR) analysis. The FT-IR spectral analyses showed the involvement of hydroxyl, carbonyl, and carboxyl groups in biosorption process. These results indicated that sugarcane bagasse biomass could be used as a novel biosorbent for the removal of Direct Violet 51 dye from real textile and related industries.

Determination of direct violet 51 dye in water based on its decolorisation by electrochemical treatment

AbstractThe decolorisation process of a synthetic textile dye, direct violet 51, was investigated in an aqueous solution using an electrochemical method in a batch electrochemical cell. Graphite electrodes were used as the anode and cathode for the decolorisation process. The parameters such as applied current, initial pH, solution conductivity, interfering ions, and effect of electrodes were optimised. It was found that the dye with an initial concentration of 20 mg L−1 could be removed after 50 min using a current of 100 mA with colour removal of up to 94 %. The UV-VIS spectra of the dye were analysed prior to and after treatment and these confirmed that the conjugated systems were decomposed at a current of 100 mA. The optimised method was successfully applied to real wastewater samples.

Adsorption Characteristics of Direct Violet Dye by Natural Rubber Chips

The study examined the adsorption behaviour of Direct Violet 51 (DV 51) dye from aqueous solution onto natural rubber chips. The effects of various operational parameters such as adsorbent dose, contact time, pH and dye concentration were investigated using the batch adsorption technique. The natural rubber sheet (thickness 2mm) was prepared by compression moulding and cut into 5 mm square pieces. The point of zero charge (pHpzc) of the rubber chips was determined using the pH drift method. Equilibrium adsorption data were analysed by means of Langmuir and Freundlich isotherms, and adsorption data by spectrophotometer. It was found that the optimum adsorbent dose was 3g and optimum contact time was 120 minutes. The highest removal efficiency was found at pH 7. The explanation may be understood in terms of the pHpzc of the rubber chip (pHpzc=7.45), at which point the rubber surface is neutral. The surface charge of the rubber chip is therefore positive when the solution pH is below pHpzc. Because of its basicity, Direct Violet therefore tends to be adsorbed onto the surface of natural rubber chips. In addition, at pH 7 common salt (NaCl) was also found, which is believed to reduce the repulsion between the rubber chips and the dye, allowing the dye to diffuse more easily on to the surface of the rubber chip fibres, thereby improving their dyeability. The adsorption data correlated well with the Langmuir isotherm model, suggesting the monolayer adsorption behaviour.

Using protein nanofibrils to remove azo dyes from aqueous solution by the coagulation process

The ever-increasing applications of hazardous azo dyes as industrialized coloring agents have led to serious remediation challenges. In this study, proteinaceous nanofibrils were examined as coagulants for decolorization of azo dyes in aqueous solutions. The results provided some insight regarding the mechanism of dye removal. The strength of nanofibrils to remove dyes from solution was evaluated by remediation of acid red 88, Bismarck brown R, direct violet 51, reactive black 5, and Congo red. However, the efficiency of nanofibrils to coagulate with different dyes was variable (60–98%) and dependent on the structures of dyes and the physicochemical conditions of the solutions. Increasing the temperature or ionic strength declined the coagulation time and induced the rate of dye removal. Changing pH had contradictory effects on the dye removal efficiency which was more affected by the chemical structure of the dye rather than the change in stability of the coagulant. The efficiency of nanofibrils to remove dyes was more than that of charcoal, which is considered as one of the most common substances used for azo dye remediation which may be due to its well dispersion in the aqueous solutions, and slower rates of the coagulation than that of the adsorption process. Furthermore, cytotoxicity was not detected after treating cell cultures with the decolorized solutions. Accordingly, by integrating biological and biophysicochemical processes, proteinaceous nanofibrils can be promising candidates for treatment of colored wastewaters. Ease of production, proper and quick dispersion in water, without the production of dangerous dye by-products and derivatives, are some of the main advantages of nanofibrils.

Comparison of photocatalytic degradation of dyes in relation to their structure

The photocatalytic degradation of a series of six acid dyes (Direct Red 80, Direct Red 81, Direct Red 23, Direct Violet 51, Direct Yellow 27, and Direct Yellow 50) has been tested compared in terms of color removal, mineralization, and toxicity (Lactuca sativa L. test) after photocatalysis on immobilized titanium dioxide. The dyes were examined at their natural pH and after hydrolysis at pH 12. Results show that hydrolysis decreases strongly the efficiency of color removal, that full mineralization takes much longer reaction time than color removal, and that toxicity is only very partially reduced. Some structural parameters, related to the structure and the topology of the dye molecules, could be correlated with the apparent color removal rates at natural pH.

Dye wastewater treatment based on a novel micro interface energy transfer process in the heterogeneous reaction

A novel thermal transfer pathway in the aqueous heterogeneous reaction was realized via the electromagnetic induction technology. Under this kind of thermal transfer, the energy acted directly on the solid particle rather than the aqueous phase. The high temperature at micro-interface would enhance the degradation of organic pollutant. In the research, the treatment of direct violet in sponge iron fixed bed reactor was selected to evaluate the performance and techniques of new energy transfer pathway. The induction heat of the filled iron in the reactor was characterized and its mean temperature was deduced on the basic of energy balance between the filled iron and the water phase. A comparative study showed that the novel technology had a better performance in the dye wastewater treatment than common fixed bed, due to the high interphase temperature which tended to promote the degradation process. The iron temperature increased with the increase of particle size, while the column filled with smaller iron particles had a better performance. Filtration rate was an important parameter and would influence the result by changing the contact time and reaction temperature at the micro-interface. Increase of the apparent temperature had a positive effect on the treatment.

Utilizing Soybean Hulls and Rice Hulls to Remove Textile Dyes from Contaminated Water

In this study we investigated the capacities of soybean hulls and rice hulls to remove various textile dyes [Safranin T (ST), Remazol Brilliant Blue R (BB), and Direct Violet 51 (DV)] from aqueous solutions. Both hull types were mixed with the dyes and analyzed for dye removal using ultraviolet–visible spectroscopy. Parameters such as sample dose, particle size, and contact time were also examined. The results demonstrate that all samples worked well at removing the ST and DV dyes (85–98 % removal). The soybean hulls worked well at removing the BB dye (72–87 % removal), while the rice hulls did not (14–35 % removal). The optimum sample dose to textile dye ratio was 3 g of sample mixed with 50 mL of dye solution. Sample particle size did not effect on the soybean hulls’ capacities to remove the dyes. However, rice hull samples with smaller particle sizes removed slightly more DV and BB dye than rice hull samples with larger particle sizes. Contact time did not have a significant impact on either hull’s capacity to remove the ST dye. However, contact time did affect the rice hulls’ capacity to remove the DV dye. Desorption results show the possibility of recycling the textile dyes. Both hull types have demonstrated the ability to be reused multiple times for textile dye removal. Therefore, soybean hulls and rice hulls may possibly be suitable media for remediating water polluted with textile dyes. Using both hull types for this purpose is feasible and will convert these waste products into value-added products.

Bioremediation of direct dyes in simulated textile effluents by a paramorphogenic form of Aspergillus oryzae

Azo dyes are extensively used for coloring textiles, paper, food, leather, drinks, pharmaceutical products, cosmetics and inks. The textile industry consumes the largest amount of azo dyes, and it is estimated that approximately 10-15% of dyes used for coloring textiles may be lost in waste streams. Almost all azo dyes are synthetic and resist biodegradation, however, they can readily be reduced by a number of chemical and biological reducing systems. Biological treatment has advantages over physical and chemical methods due to lower costs and minimal environmental effect. This research focuses on the utilization of Aspergillus oryzae to remove some types of azo dyes from aqueous solutions. The fungus, physically induced in its paramorphogenic form (called 'pellets'), was used in the dye biosorption studies with both non-autoclaved and autoclaved hyphae, at different pH values. The goals were the removal of dyes by biosorption and the decrease of their toxicity. The dyes used were Direct Red 23 and Direct Violet 51. Their spectral stability (325-700 nm) was analyzed at different pH values (2.50, 4.50 and 6.50). The best biosorptive pH value and the toxicity limit, (which is given by the lethal concentration (LC(100)), were then determined. Each dye showed the same spectrum at different pH values. The best biosorptive pH was 2.50, for both non- autoclaved and autoclaved hyphae of A. oryzae. The toxicity level of the dyes was determined using the Trimmed Spearman-Karber Method, with Daphnia similis in all bioassays. The Direct Violet 51 (LC(100) 400 mg · mL(-1)) was found to be the most toxic dye, followed by the Direct Red 23 (LC(100) 900 mg · mL(-1)). The toxicity bioassays for each dye have shown that it is possible to decrease the toxicity level to zero by adding a small quantity of biomass from A. oryzae in its paramorphogenic form. The autoclaved biomass had a higher biosorptive capacity for the dye than the non-autoclaved biomass. The results show that bioremediation occurs with A. oryzae in its paramorphogenic form, and it can be used as a biosorptive substrate for treatment of industrial waste water containing azo dyes.

Direct-dyes bioremoval using Aspergillus niger in pilot scale bioreactor

Treatment of effluents from dye-based industries represents one of the most important approaches to protect the surrounding agricultural environment from heavy pollutions particularly in developing countries. In this work, decolorization of two structurally different direct textile dyes; Direct Violet and Direct Green, were studied to determine the optimum conditions for dye removal, particularly in relation to agitation rate and temperature. Experiments on the decolorization of the dyes were carried out in a batch mode bioreactor using Aspergillus niger strain 20. The effect of various temperatures (30°C, 35°C, 40°C, 45°C, 50°C) and agitation rates (0, 100, 200, 300 and 400 rpm) on the dye removal were investigated. The maximum removal of Direct Green dye was recorded at temperature 40°C, where 75.75% of this dye was removed in 2 h. The data revealed that the agitation has a significant effect on the percentage of the dye decolorization by fungal biomass. The removal ranged from 72.3 to 96.6 after 24 h. ...