Direct Black 38 Research Articles

Efficient removal of azo dyes by Enterococcus faecalis R1107 and its application in simulated textile effluent treatment

This study aimed to exploit the potential of Enterococcus faecalis R1107 in the bioremediation of azo dyes. The maximal decolorization of Congo Red (CR), Reactive Black 5 (RB5), and Direct Black 38 (DB38) were 90.17%, 96.82%, and 81.95%, respectively, with the bacterial treatment for 48 h. 65.57% of CR and 72.64% of RB5 could be decolorized by E. faecalis R1107 within 48 h when the concentration of azo dyes increased up to 1000 mg/L. FTIR analysis confirmed that E. faecalis R1107 could effectively break down the chemical structures of three azo dyes. E. faecalis R1107 alleviated the phytotoxicity of azo dyes and improved seed germination, which contributed to the increase in the lengths of roots, stems, and leaves of Vigna radiata seedlings. Transcriptomic analysis suggested that the gene regulatory networks in E. faecalis R1107 synergistically improved the degradation and detoxification of RB5, including the major metabolic pathways, the secondary metabolism, the transport system, the amino acid metabolic pathways, and the signal transduction systems. Simulated textile effluent (STE) was used to mimic real textile effluent to evaluate the bioremediation potential of E. faecalis R1107, and 72.79% STE can be decolorized after E. faecalis R1107 treatment for 48 h. In summary, our study demonstrated that E. faecalis R1107 might be well suitable for potential applications in the bioremediation of textile effluent.

ZIF-8 channeled and coordination-bridging two-dimensional WS2 membrane for efficient organic solvent nanofiltration

Zeolitic imidazolate framework-8 (ZIF-8)/WS2 composite 2D membranes were constructed by in-situ growth of ZIF-8 in the interlayer of WS2 laminar membrane. The growth of ZIF-8 nanoparticles in WS2 membrane expanded the interlayer spacing, and endowed WS2 membrane with fixed interlayer spacing by coordination-bridges between WS2 and ZIF-8, which made ZIF-8/WS2 membrane possess not only high solvent permeance but also excellent stability in organic solvents. Isopropanol (IPA) permeance through ZIF-8/WS2 membrane reached 272 L/m2·h·bar, which was about 1.6 times higher than that through pristine WS2 membrane, and the rejection rates for Direct Black 38 (DB38), Congo Red (CR) and Rose Bengal (RosB) were 99%, 99% and 30% respectively. Furthermore, the IPA permeance through ZIF-8/WS2 membrane was almost unchanged after soaking in IPA for 192 h, and IPA permeance and rejection rate for DB 38 changed slightly during 100 h of cross-flow filtration, demonstrating remarkable stability of ZIF-8/WS2 membranes in organic solvents and a promising application potential in organic solvent nanofiltration.

Ball-milled Cu2S nanoparticles as an efficient additive for modification of the PVDF ultrafiltration membranes: Application to separation of protein and dyes

This study reports the fabrication and application of polyvinylidene fluoride (PVDF) ultrafiltration membranes embedded with various concentrations of the Cu2S nanoparticles. The Cu2S nanoparticles were generated from natural chalcocite applying a high energy planetary ball-milling technique. Non-solvent induced phase separation method was used for the fabrication of the membranes and characterized with scanning electron microscopy (SEM), energy dispersive X-ray (EDX), atomic force microscopy (AFM), porosity and static water contact angle measurements. The results of the contact angle and porosity revealed the increased hydrophilicity and porosity of the nanocomposite membranes as a result of the addition of Cu2S leads to water permeation improvement. The nanocomposite membrane with 0.2 wt% of Cu2S nanoparticles exhibited a maximum water flux of 248.25 Lm−2 h−1 and flux recovery ratio (FRR) value of 92.4%, which showed 65% and 19% increase compared with the control PVDF membrane. Meanwhile, the nanocomposite membranes were able to highly reject the anionic dyes such as reactive blue 21 (RB21), direct black 38 (DB38), and direct yellow 12 (DY12).

Effective Removal of the Direct Black-38 Dye from Wastewater Using a New Silica-Modified Resin: Equilibrium and Thermodynamics Modeling Studies

In this study, the synthesis of p-diethanolaminomethylcalix[4]arene and its immobilization on a silica surface have been performed for the removal of the direct black (DB-38) dye from wastewater sa...

Two-dimensional Montmorillonite membranes with efficient water filtration

Two-dimensional (2D) Montmorillonite (MMT) membranes have been developed by exfoliation MMT nanosheets and vacuum filtration, and their separation performances were investigated in details. The hydrated lamellar MMT membrane with a thickness of 600 nm shows a water permeance of 212.2 L/m2·h·bar and a rejection rate of 95.6% for Direct Black 38 (DB38). Moreover, the lamellar MMT membrane maintained high stability under acid and alkaline solutions, and the separation performance changed slightly after soaking in 0.5 M H2SO4, 0.5 M NaOH and 0.5 M HCl solutions, respectively. The MMT membrane also exhibited good resistance to shearing force during a 48 h of cross-flow filtration with a slight decrease of water permeance. In addition, a high flux recovery ratio of 88.2% was achieved for the MMT membrane after filtration of BSA solution, suggesting an excellent antifouling property of the MMT membrane. The high water permeance, excellent stability and antifouling property make these 2D MMT membranes promising in water filtration.

Response Surface Methodology for Optimization of Enzyme-Catalyzed Azo Dye Decolorization

AbstractAzo dyes are a water-pollution problem causing damage to ecosystems and human health. Soybean peroxidase–catalyzed reactions of azo dyes, Acid blue 113 (AB113) and Direct black 38 (DB38), w...

Magnetic MCM-41 silica particles grafted with poly(glycidylmethacrylate) brush: Modification and application for removal of direct dyes

Magnetic MCM-41composite particles were prepared and modified with (3-aminopropyl) triethoxysilane (APTES), then grafted with poly(glycidyl methacrylate) p(GMA) by surface-initiated atom transfer radical polymerization (SI-ATRP). The p(GMA) grafted magnetic MCM-41 particles were functionalized with tris(2-aminoethyl)amine (TAEA), and used as a cationic adsorbent for the adsorptive removal of Direct Blue 6 (DB-6) and Direct Black-38 (DB-38) from aqueous medium. The mMCM-41 and mMCM-41-p(GMA)-TAEA particles were characterized by BET, X-ray diffraction (XRD), thermogravimetric (TGA), Fourier transform infrared spectroscopy (ATR-FT-IR), Zeta potential, nitrogen adsorption–desorption isotherms (BET method), scanning electron microscope (SEM) and analytical methods. VSM data shows that the mMCM-41-p(GMA)-TAEA display a paramagnetic behavior with saturation magnetization of about 19.6 emu/g. Adsorption potential of two different textile dyes (i.e., DB-6 and DB-38) was evaluated by varying experimental conditions (i.e., pH, temperature, ionic strength and initial dye concentration). Both dyes were removed from aqueous medium with high efficiency in a wide pH range of 4.0–7.0. The equilibrium adsorption data were analysed by Langmuir, and Freundlich models. The experimental equilibrium data was found to fit the Langmuir model well for adsorption of DB-6 and DB-38 dyes on the mMCM-41-g-p(GMA)-TAEA particles. The adsorption kinetic data were also analysed using pseudo-first order, and pseudo-second-order kinetic equations. It was found that the pseudo second-order model can describe the adsorption data well. The presented adsorbent can be regenerated using 0.1 M HNO3 solution and desorption efficiency was more than 96%. Hence, mMCM-41composite particles were very stable, and easily regenerated.

Synthesis of hollow porous carbon nanospheres from coal tar for adsorption of Direct Black 38 dye

A hollow porous carbon nanospheres (HPCNs) material which suits for adsorption of Direct Black 38 (DB38) was prepared from coal tar using zinc acetate as a template coupled with KOH activation. The synthesized HPCNs features with nanospheres structure and contains both micropores and a lot of mesopores. The HPCN1−4−2 made with the mass weight ratio of coal tar/zinc acetate/KOH at 1:4:2 shows a large surface area of 1374 m2 g−1 with an average pore size of 7.41 nm. The HPCN1−4−2 exhibits excellent adsorption capacity for DB38 dye, which has big molecular size at room temperature. This is mainly due to its large surface area and pore volumes contributed by its mesopores. This work suggests an effective way to synthesize a high performance adsorbent for large molecular size dyes from low-cost coal tar.

Preparation of activated carbon from peanut shell by conventional pyrolysis and microwave irradiation-pyrolysis to remove organic dyes from aqueous solutions

Activated carbon samples were prepared from peanut shell by conventional pyrolysis (P sample) and microwave irradiation followed by pyrolysis (MW-P sample). These samples as well as peanut shell were characterized by N2 adsorption/desorption isotherms (BET), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), being applied to remove Direct Black 38 (DB38) and Reactive Red 141 (RR141) dyes from aqueous solutions. In order to evaluate the performance of adsorption process, pH effect, kinetic, equilibrium and desorption studies were carried out in this work. It was found that the MW-P sample exhibited superior characteristics such as texture, surface area, pore volume and pore size than the peanut shell and P sample. In addition, MW-P presented higher values of adsorption capacity, mainly at pH 2.5. The pseudo-second order kinetic model was suitable to represent the adsorption of DB38 and RR141 dyes on the MW-P sample. The Sips isotherm model was adequate to represent the adsorption of DB38 and RR141 on the MW-P sample, being the maximum adsorption capacities of 110.6 and 284.5mgg−1, respectively. The dyes were desorbed from MW-P sample using an alkaline solution. The results demonstrated that the microwave irradiation followed by pyrolysis is an alternative way to prepare an activated carbon with interesting characteristics and high adsorption capacities for organic dyes.

Synthesis and adsorption efficiency of calix[6]arene appended XAD-4 resin

This study describes the synthesis of calix[6]arene hexaester appended Amberlite XAD-4 (resin 2) and its application for the removal of reactive blue-5 (RB-5) and direct black-38 (DB-38) azo dyes from aqueous media. The newly synthesized resin 2 was characterized by using various analytical techniques such as FTIR spectroscopy, elemental analysis, scanning electron microscope, and thermogravimetric analysis. In this approach, adsorption efficiency of resin 2 for azo dyes was explored by optimizing various parameters such as pH, adsorbent dose, role of electrolytes, and contact time. From results it has been observed that percentage adsorption of these azo dyes is highly dependent on pH of the solution. The maximum adsorption of RB-5 and DB-38 was achieved at pH 3 and pH 9, respectively. Isotherm evaluation has judged that adsorption behavior can be better demonstrated by Langmuir and D–R models. The kinetic studies revealed that removal process of selected dyes follow pseudo-second-order kinetic model. The positive and negative values of ΔH and ΔG, respectively, confirm the endothermic and spontaneous nature of this adsorption process. Moreover, results shows that resin 2 has proved highly effective adsorbent for the removal of azo dyes from aqueous environment.

Preparation and Characterization of Porous Horseradish Peroxidase Microspheres for the Removal of Phenolic Compound and Dye

In this article, a simple, versatile, and mild method was used to fabricate porous enzyme microspheres using CaCO3 microparticles as templates. The preparation process involved three steps including coprecipitation of enzyme with CaCO3, cross-linking, and template removal. The preparation process was optimized and the obtained porous horseradish peroxidase (HRP) microspheres (p-HRP) were characterized. The p-HRP exhibited improved thermal stability and was more stable under alkali conditions than its free counterpart. These features are attractive for practical applications. Compared to free HRP, the Km value of p-HRP was increased and the Vmax value was decreased. The catalytic performance of p-HRP in removing phenolic compound and dye from aqueous solution was explored by using phenol and Direct Black-38 as model substrates. The results indicated that p-HRP exhibited high removal efficiency and moderately good reusability.

Immobilization of horseradish peroxidase in phospholipid-templated titania and its applications in phenolic compounds and dye removal

In this study, horseradish peroxidase (HRP) was encapsulated in phospholipid-templated titania particles through the biomimetic titanification process and used for the treatment of wastewater polluted with phenolic compounds and dye. The encapsulated HRP exhibited improved thermal stability, a wide range of pH stability and high tolerance against inactivating agents. It was observed an increase in Km value for the encapsulated HRP (8.21mM) when compared with its free counterpart. For practical applications in the removal of phenolic compounds and dye by the encapsulated HRP, the removal efficiency for phenol, 2-chlorophenol, Direct Black-38 were 92.99%, 87.97%, and 79.72%, respectively, in the first treatment cycle. Additionally, the encapsulated HRP showed better removal efficiency than free HRP and a moderately good capability of reutilization.

Adsorption of direct black-38 azo dye on p-tert-butylcalix[6]arene immobilized material

The present study demonstrates the adsorption of the direct black-38 (DB-38) azo dye on potential and newly synthesized p-tert-butylcalix[6]arene based silica resin (4). Resin 4 was synthesized via the modification of pure silica 1 as 2 followed by the immobilization of p-tert-butylcalix[6]arene (3) onto modified silica (2). It was characterized by using different analytical techniques such as FT-IR, scanning electron microscopy (SEM) and thermo gravimetric analysis (TGA). The effect of adsorbent dosage, pH and the electrolyte effect on the removal of the DB-38 azo dye were evaluated through batch wise adsorption experiments. Maximum adsorption of 91% was achieved at pH 9.0. The textile wastewater samples were used to ensure the field applicability of the newly synthesized adsorbent 4 for the treatment of dye contaminated effluents. All results regarding the removal of the DB-38 azo dye from the aqueous environment prop up resin 4 as an effective adsorbent and it was found that resin 4 has high adsorption efficiency toward the DB-38 azo dye at a wide range of pH as compared to 1 and 2.

Cross-linking of horseradish peroxidase adsorbed on polycationic films: utilization for direct dye degradation

Horseradish peroxidase (HRP) was immobilized on the polyaniline (PANI) grafted polyacrylonitrile (PAN) films. The maximum HRP immobilization capacity of the PAN-g-PANI-3 film was 221μg/cm(2). The HRP-immobilized PAN-g-PANI-3 film retained 79% of the activity of the same quantity free enzyme. The HRP-immobilized PAN-g-PANI-3 film was operated for the decolorization of two different benzidine-based dyes in the presence of hydrogen peroxide. The maximum decolorization grade was obtained at pH 6.0 for both dyes. The HRP-immobilized PAN-g-PANI-3 film was very effective for removal of Direct Blue-53 compared to Direct Black-38 from aqueous solutions. The immobilized HRP exhibited high resistance to proteolysis by trypsin compared to the free counterpart. Immobilized HRP preserved 83% of its original activity even after 8weeks of storage at 4°C, while the free enzyme lost its initial activity after 3weeks of storage period.

Effects of Ethanol and Phenobarbital on Hemoglobin Adducts Formation in Rats Exposed to Benzidine and Direct Black 38

The objective of this study was to evaluate the effects of pretreatment of ethanol (EtOH) and phenobarbital (PB), which are known to affect the metabolism of xenobiotics, in the formation of hemoglobin adducts in rats administered with benzidine (BZ) and Direct Black 38 (DB38). The experimental rats were divided into BZ and DB38 groups; each group was subdivided into control, EtOH, and PB groups. Blood samples were separated into hemoglobin and plasma immediately after obtaining and basic hydrolysis was done to convert the adducts into aromatic amines. Hydrolyzed BZ, monoacetylbenzidine (MABZ), and 4-aminobiphenyl (4ABP) were separated by reversed-phase liquid chromatography without derivatization. Then, quantitative analyses were performed using a high performance liquid chromatograph equipped with an electrochemical detector. The amount of metabolites was expressed in the hemoglobin binding index (HBI). As a result, the formations of hemoglobin in BZ-, MABZ-, and 4ABP-HBI of BZ-EtOH and BZ-PB groups were increased compared with those of BZ-control group. In DB38 group, all of HBIs except for BZ-HBI were increased more than those of DB38-control group regardless of the pretreatment. These results are attributable to the fact that EtOH and PB induced N-hydroxylation is related to the formation of hemoglobin adducts. They indicate that EtOH not only increases the adduct formation by inducing N-hydroxylation but also induces N-acetylation. PB induced N-hydroxylation and increased the adduct formation in BZ group, but decreased the adduct formation in DB38 group due to decreasing azo reduction. These results suggest that the effects of EtOH or PB should be considered in biochemical monitoring of BZ and DB38 for the assessment of intermittent exposure to BZ and DB38.

Detoxification of benzidine-based azo dye by E. gallinarum: Time-course study

Direct black 38 (DB38) dye is a well-established toxic and carcinogenic compound. Present investigation reports isolation of an Enterococcus gallinarum strain capable of decolorizing and degrading it. Changes in toxicity and mutagenicity of DB38 and its metabolites were also determined using a battery of carefully selected tests (cytotoxicity, respiration inhibition test and Ames test). Toxicity assays were carried out on E. gallinarum itself as this also gave information about suitability of this strain for the dye decolorization operation. The strain was found to reduce both toxicity and mutagenicity of DB38 metabolites. Benzidine and 4-aminobiphenyl (4-ABP) were identified as the DB38 metabolites, responsible for its toxic and mutagenic properties, by HPLC-MS analysis. Further degradation of benzidine and 4-ABP was found to result in the decrease in toxicity and mutagenicity.

Biological decolourization of C.I. Direct Black 38 by E. gallinarum

In the present study, an Enterococcus gallinarum strain was isolated from effluent treatment plant of a textile industry based on its ability to decolourize C.I. Direct Black 38 (DB38), a benzidine-based azo dye. Effects of dye concentration and medium composition on dye decolourization were studied. The strain was found to decolourize DB38 even under aerobic conditions. Kinetics of DB38 decolourization was also examined, and V max and K s of decolourization were found to be higher in Luria broth (12.8 mg l −1 h −1 and 490.6 mg l −1) than in minimal medium (4.09 mg l −1 h −1 and 161.84 mg l −1). However, decolourization rate/biomass was found to be higher in minimal medium than in Luria broth, indicating greater decolourization efficiency of biomass in the former. The study also revealed biodegradation of DB38 to benzidine and its further deamination to 4-aminobiphenyl (4-ABP) by the culture. Ammonia released during this process was used as nitrogen source for growth of the culture.

Kinetics of decolourisation and biotransformation of direct black 38 by C. hominis and P. stutzeri

In the present study, a consortium of Cardiobacterium hominis and Pseudomonas stutzeri was isolated from an effluent treatment plant of a textile industry, based on its ability to decolourise azo dyes including direct black 38 (DB38), a benzidine-based azo dye. The role of each culture in the decolourisation process was elucidated, and C. hominis was found to decolourise the dye. Although P. stutzeri could not decolourise the dye, it was found to synergistically enhance dye decolourisation activity of C. hominis by scavenging oxygen in the medium and creating an anaerobic condition (oxidation/reduction potential -440 mV), which is known to be necessary for azo dye decolourisation. Together, the cultures could decolourise 90.5% of 100 mg l(-1) DB38 within 24 h. Kinetics of DB38 decolourisation was also examined, and P. stutzeri was found to increase V (max) and K (m) of decolourisation activity of C. hominis by 3.6- and 3-fold, respectively. The study also revealed a pathway of DB38 degradation with the release of benzidine from DB38 and subsequent degradation of benzidine to 4-aminobiphenyl by the cultures.

Decolorisation, biodegradation and detoxification of benzidine based azo dye

The present study deals with the decolorisation, biodegradation and detoxification of Direct Black-38, a benzidine based azo dye, by a mixed microbial culture isolated from an aerobic bioreactor treating textile wastewater. The studies revealed a biotransformation of Direct Black-38 into benzidine and 4-aminobiphenyl followed by complete decolorisation and biodegradation of these toxic intermediates. From cytotoxicity studies, it was concluded that detoxification of the dye took place after degradation of the toxic intermediates by the culture.

Induction of unscheduled DNA synthesis in liver and micronucleus in bone marrow of rats exposed in vivo to the benzidine-derived azo dye, Direct Black 38

The genotoxic activity of the benzidine-derived azo dye, Direct Black 38 (DB38), was studied in vivo, using two different genetic end-points: unscheduled DNA synthesis in liver (UDS) and bone marrow micronucleus (MN). Exposure times were 12, 24 or 36 h. Both assays were performed in the same rat, except for the 24-h exposure when only MN was investigated. For the liver UDS assay, the rat hepatocarcinogen, 6-dimethylaminophenylazobenzthiazole (6BT), was used as positive control and for the MN assay, cyclophosphamide (CP). In agreement with earlier results, 6BT gave rise to a dose-related increase in liver UDS after 12-h exposure to 25 or 50 mg/kg bw. After 36-h exposure, there was still an indication of a weak dose-response effect between 0 and 5 net nuclear grains (NG). DB38 induced liver UDS at the higher dose levels used (500 and 1000 mg/kg), and after both 12- and 36-h exposure. With the longer exposure time, a weak induction of UDS was also observed at 100 mg/kg. The strongest UDS induction (12.2 NG), was obtained in one rat after 36-h exposure to 500 mg/kg. DB38 also had a weak effect on the MN induction, which was statistically significant at the higher concentrations used. A dose-related response was observed at all exposure times used.