Scarlet GR Research Articles

Meta-genome analysis of a newly enriched azo dyes detoxification halo-thermophilic bacterial consortium

Treating textile wastewaters were always inhibited by its higher salt concentration and temperature. In this study, a halo-thermophilic bacterial consortium YM was enriched with ability to decolorize acid brilliant scarlet GR (ABS) at 55 °C and 10% salinity. Under optimum conditions of pH (8), temperature (55 °C), and salinity (10%), YM decolorized 97% of ABS under anaerobic conditions. Alteribacillus was identified to be the dominant genus in consortium YM. Consortium YM showed significant decolorization ability under a wide range of salinity (1%–10%), pH (7–9) and temperature (45 °C–60 °C). The degradation pathway of ABS was proposed by the combination of UV–vis spectral analysis, Fourier transform infrared (FTIR), gas chromatography mass spectrometric (GC-MS), and metagenomic analysis. Azoreductase, which was an important enzyme in decolorization process, was identified with great variation in the genome of consortium YM. Meanwhile, the metabolic intermediates after decolorization was identified with low biotoxicity by phytotoxicity tests. This study first identified that Alterbacillus play an important role in azo dye decolorization and degradation process under halo-thermophlic conditions and provided significant knowledge for azo dye decolorization and degradation process.

The synergistic activation of peroxymonosulfate for the degradation of Acid Scarlet GR by palygorskite/MnO2/Fe3O4 nanocomposites.

A heterogeneous Fenton-like system comprising palygorskite/MnO2/Fe3O4 (PMM) as a superior, low-cost, and eco-friendly ternary catalyst for the activation of peroxymonosulfate (PMS) was investigated with regard to its ability to degrade Acid Scarlet GR in an aqueous solution. Under the optimum catalytic oxidation conditions of 1 g L-1 PMM, 0.7 g L-1 PMS, and an initial pH value of 5, 200 mg L-1 Acid Scarlet GR was completely degraded within 300 min. PMM exhibited outstanding magnetic recovery ability and reusability after nine cycles with a degradation efficiency of up to 95.4%. The PMM catalyst had a broad working pH range. Singlet oxygen 1O2 was considered to play the principal role in the degradation of Acid Scarlet GR in the PMM/PMS system. The synergistic effect between MnO2, Fe3O4, and PG substantially accelerated the catalytic activity of PMM, and MnO2 was identified to be the primary active site. These findings indicate that PMM is a nanocatalyst that can efficiently activate PMS for the treatment of dye-containing wastewater.

Aerobic decolorization and detoxification of Acid Scarlet GR by a newly isolated salt-tolerant yeast strain Galactomyces geotrichum GG

Azo dyes are huge social and environmental hazards. Selective fungi are potential degraders for azo dyes and are of great significance to cleaning up and bioremediation. In this study, a salt-tolerant yeast strain GG with the ability to aerobically degrade and detoxify various azo dyes was isolated and identified as Galactomyces geotrichum. The optimal growth and decolorization parameters of strain GG were 0.1 g/L of yeast extract, 2.0 g/L of glucose, 0.4 g/L of ammonium sulfate, ≤ 40 g/L of NaCl, and pH values of 7.0–8.0. Under the optimal condition more than 92% of 100 mg/L of Acid Scarlet GR could be decolorized within 10 h by degradation, which was further confirmed by Fourier transform infrared spectroscopy. In addition, enzymatic analysis showed that the reductase NADH-DCIP and two oxidoreductases lignin peroxidase and laccase played the key roles in the degradation of Acid Scarlet GR, and the decolorization metabolites of Acid Scarlet GR exhibited much less toxicity than the parent dye by phytotoxicity assessment. The results improved the knowledge of azo-dye-decolorizing G. geotrichum species and provided efficient fungal resource for treatment of industrial wastewater containing azo dyes and salts.

Performance of a newly enriched bacterial consortium for degrading and detoxifying azo dyes.

To obtain a bacterial consortium that can degrade azo dyes effectively, a bacterial consortium was enriched that can degrade Metanil yellow effectively. After 6 h, 96.25% Metanil yellow was degraded under static conditions by the bacterial consortium, which was mainly composed of Pseudomonas, Lysinibacillus, Lactococcus, and Dysgonomonas. In particular, Pseudomonas played a main role in the decolorization process. Co-substrate increased the decolorization rate, and yeast powder, peptone, and urea demonstrated excellent effects. The optimal pH value and salinity for the decolorization of azo dyes is 4-7 and 1% salinity respectively. The bacterial consortium can directly degrade many azo dyes, such as direct fast black G and acid brilliant scarlet GR. Azo reductase activity, laccase activity, and lignin peroxidase activity were estimated as the key reductase for decolorization, and Metanil yellow can be degraded into less toxic degradation products through synergistic effects. The degradation pathway of Metanil yellow was analyzed by Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry, which demonstrated that Metanil yellow was cleaved at the azo bond, producing p-aminodiphenylamine and diphenylamine. These findings improved our knowledge of azo-dye-decolorizing microbial resources and provided efficient candidates for the treatment of dye-polluted wastewaters.

Isolation, cloning and characterization of an azoreductase and the effect of salinity on its expression in a halophilic bacterium

Understanding the molecular mechanisms of azo dye decolorization is important for the development of effective bioremediation for textile-colored wastewater. A halophilic bacterium Halomonas sp. strain GT was isolated, which could degrade the azo dye Acid Brilliant Scarlet GR at 10% NaCl. The complete genome sequence of this strain was obtained using the PacBio RS II platform. Genome annotation revealed that four proteins are related to decolorization of azo dyes, such as azoreductase, laccases, benzene 1,2-dioxygenase, and catechol 1,2-dioxygenase. The putative azoreductase gene of Halomonas sp. strain GT responsible for the decolorization of azo dye in high salt environment was isolated. Phylogenetic tree analysis showed that the azoG (azoreductase gene of Halomonas sp. strain GT) and its homologs constituted a new branch of the NADH depending azoreductases, with all the homologous sequence of the protein from halophilic bacteria. At high NaCl concentrations, azoreductase gene expression and azoreductase activity were restrained in Halomonas sp. strain GT, which resulted in low a decolorization rate.

One-Step Fabrication of Dual Responsive Lignin Coated Fe3O4 Nanoparticles for Efficient Removal of Cationic and Anionic Dyes

A new, simple one-step approach has been developed to synthesize lignin and lignin amine coated Fe3O4 nanoparticles. These nanoparticles (lignin magnetic nanoparticles (LMNPs) and lignin amine magnetic nanoparticles (LAMNPs)) are found to possess not only magnetic response but also pH-dependent adsorption behavior. Results show that the combination of lignin with nanoparticles increased the adsorption capacities 2–5 times higher than other traditional single lignin based adsorbents (211.42 mg/g for methylene blue (MB) by LMNPs and 176.49 mg/g for acid scarlet GR (AS-GR) by LAMNPs). Meanwhile, by simply adjusting the pH, the dye-loaded adsorbents can be regenerated to recycle both adsorbents and dyes with a desorption efficiency up to 90%. Mechanistic study shows that dye structure and surface charges of adsorbents play the most important part in adsorption where dyes interact with the adsorbent surface via π–π stacking and electrostatic attraction interactions. The efficient fabrication method, eco-friendly reactant, quick magnetic separation, high adsorption and desorption efficiency suggest this novel type of nano-adsorbents to be promising materials for efficient dye pollutant removal and recovery.

Biosynthesis of gold nanoparticles by Aspergillum sp. WL-Au for degradation of aromatic pollutants

A simple method for synthesis of gold nanoparticles (AuNPs) using Aspergillum sp. WL-Au was presented in this study. According to UV–vis spectra and transmission electron microscopy images, the shape and size of AuNPs were affected by different parameters, including buffer solution, pH, biomass and HAuCl4 concentrations. Phosphate sodium buffer was more suitable for extracellular synthesis of AuNPs, and the optimal conditions for AuNPs synthesis were pH 7.0, biomass 100mg/mL and HAuCl4 3mM, leading to the production of spherical and pseudo-spherical nanoparticles. The biosynthesized AuNPs possessed excellent catalytic activities for the reduction of 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, o-nitroaniline and m-nitroaniline in the presence of NaBH4, and the catalytic rate constants were calculated to be 6.3×10−3s−1, 5.5×10−3s−1, 10.6×10−3s−1, 8.4×10−3s−1 and 13.8×10−3s−1, respectively. The AuNPs were also able to catalyze the decolorization of various azo dyes (e.g. Cationic Red X-GRL, Acid Orange II and Acid scarlet GR) using NaBH4 as the reductant, and the decolorization rates reached 91.0–96.4% within 7min. The present study should provide a potential candidate for green synthesis of AuNPs, which could serve as efficient catalysts for aromatic pollutants degradation.

Bioflocculant production by Haloplanus vescus and its application in acid brilliant scarlet yellow/red removal.

A novel bioflocculant MBF057 produced by a salt-tolerant Haloplanus vescus HW0579 was investigated in this study. The effects of culture conditions such as initial pH, inoculum size, and chemical oxygen demand (COD) of K-acid wastewater on MBF0579 production were studied. The result showed that 8.09 g/L purified MBF0579 was extracted with the following optimized conditions: 780 mg/L COD of K-acid wastewater as carbon source, inoculum size 12.5%, and initial pH 7.0. The biopolymer contained 78.6% polysaccharides and 21.1% proteins. The highest flocculating rate of 81.86 and 95.07% for the COD and chroma of acid brilliant scarlet gelb rot (yellow/red, GR) dye wastewater were achieved at a dosage of 150 mg/L, pH 2.0 and contact time 100 min. Overall, these findings indicate bioflocculation offers an effective alternative method of decreasing acid brilliant scarlet GR during dye wastewater treatment.

Mechanisms and Properties of Chitosan-Assisted Bamboo Dyeing

Acid dyes are often used to improve the decorative properties of bamboo products. However, the use of these dyes is problematic because they run easily. This study examined the use of chitosan as a fixing agent to address this issue. The study also investigated the interaction between dyed bamboo powder and dyed veneers pre-treated with chitosan. Powder was dyed at various pH values with acid scarlet GR and soaked in various solvents. Analyses were conducted using Fourier transform infrared spectroscopy, a zeta potential measurement analyzer, UV-visible spectroscopy, and a color measuring instrument. Pre-treated bamboo veneers were also dyed with acid scarlet GR and evaluated with the color measuring instrument, a scanning electron microscope, and an optical microscope. Chitosan functioned as a bridge and immobilized dye on the bamboo. This occurred through a chemical reaction and opposite charge attraction under acidic conditions. Pretreated dyed bamboo veneers demonstrated excellent dye uptake, color-fastness, and levelness. Therefore, chitosan shows promise for use as a fixing agent in dyed bamboo.

Evaluating the Effects of Silent Discharge Plasma on Remediation of Acid Scarlet GR-Contaminated Soil

The remediation of dye-contaminated soil using silent discharge plasma in dielectric barrier discharge (DBD) reactor was reported in this study. Acid scarlet GR was selected as the representative of azo dye pollutants. Effects of applied voltage, discharge frequency, and gas flow rate on Acid scarlet GR treatment effect which were characterized by degradation efficiency and the change of chemical oxygen demand (COD) during the degradation were investigated. The decolorization rate of Acid scarlet GR in the soil increased with the applied voltage and discharge frequency, and the optimal gas flow rate was obtained at 1.0 L min−1. The energy efficiency was clearly enhanced by way of increasing the amount of contaminated soil in the DBD reactor finitely. The degradation efficiency of Acid scarlet GR and the removal of COD value were achieved 93 % and 74 % after 25-min discharge treatment, respectively. The results indicated that the DBD remediation system was able to degrade Acid scarlet GR in the soil quickly and efficiently. This study is expected to provide a possible pathway of Acid scarlet GR degradation in soil.

Removal of dyes from aqueous solution by activated carbon from sewage sludge of the municipal wastewater treatment plant

Activated carbon from sewage sludge of the municipal wastewater treatment plant was obtained by chemical activation with ZnCl2 as activator. Then, it was used as an adsorbent for the removal of Acid Scarlet GR and Methylene Blue from aqueous solution. The effects of contact time, temperature, and initial dye concentration were investigated. The experimental data were analyzed by the Langmuir and Freundlich adsorption models. Kinetic adsorption data were discussed using the pseudo-first-order model and pseudo-second-order model. Thermodynamic parameters, such as enthalpy (ΔH°), entropy (ΔS°), and Gibbs free energy (ΔG°), were calculated. The results showed that the equilibrium data fitted well with the Freundlich model for the adsorption of Methylene Blue on the activated carbon. However, adsorption data for Acid Scarlet GR were both fitted with the Langmuir isotherm and the Freundlich isotherm. The adsorption kinetic of Methylene Blue and Acid Scarlet GR on the activated carbon was both more accurately represented by pseudo-second-order model. The values of ΔH°, ΔS°, and ΔG° for adsorption of Methylene Blue were 53.01 kJ/mol, 190.12 J/mol and −2.78 kJ/mol, respectively. The absorption process of Methylene Blue was a spontaneous and endothermic reaction. The values of ΔH°, ΔS°, and ΔG° for adsorption of Acid Scarlet GR were 32.78 kJ/mol, 104.00 J/mol and 2.26 kJ/mol, respectively. The adsorption process of Acid Scarlet GR was less effective.

Aerobic decolorization of Acid Brilliant Scarlet GR by microbial community and the community dynamics during sequencing batch processes

In this research, aerobic decolorization of Acid Brilliant Scarlet GR by microbial community was studied. Effects of conditions and dye concentraion on decolorization processes were investigated. Additionally, continuous decolorization was evaluated through sequencing batch tests and the microbial dynamics during this process was analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis. The results showed that 100 mg l⁻¹ of the dye was completely decolorized within 12 h, which was mainly caused by biodegradation. The optimal decolorization conditions were as follows: inoculation size 2.07 g l⁻¹ (wet cell pellet), rotation speed 150 r min⁻¹, pH 5.0-7.0 and 30 °C. The processes were well described by zero-order kinetics, and more than 700 mg l⁻¹ of the dye would inhibit the activity of the consortium. Furthermore, the microbial community exhibited high efficiency in sequencing batch processes for continuous decolorization. Microbial community structure shifted obviously when exposed to higher concentration of the dye (500 mg l⁻¹), and all the dominant microorganisms were affiliated with four different phyla of Actinobacteria, Bacteroidetes, Proteobacteria and Firmicutes.

Aerobic decolorization and degradation of azo dyes by growing cells of a newly isolated yeast Candida tropicalis TL-F1

The aim of this work was to investigate the decolorization and degradation of azo dyes by growing cells of a new yeast strain TL-F1 which was isolated from the sea mud. Strain TL-F1 was identified as Candida tropicalis on the basis of 28S rDNA analysis. Various azo dyes (20mg/L) were efficiently decolorized through aerobic degradation. Meantime, the effects of different parameters on both decolorization of Acid Brilliant Scarlet GR and growth of strain TL-F1 were investigated. Furthermore, possible degradation pathway of the dye GR was proposed through analysis of metabolic products using UV-Vis spectroscopy and HPLC-MS methods. As far as it is known, it is the first systematic research on a C. tropicalis strain which is capable of efficiently decolorizing various azo dyes under aerobic condition. This work provides a potentially useful microbial strain TL-F1 for treatment of azo dye contaminated wastewater.

Effect of different plants on azo-dye wastewater bio-decolorization

Two salt-tolerant plants (Medicago sativa L. and Sesbania cannabina Pers) as well as a kind of salt-tolerant azo-dye decolorization bacteria GTY (Gracilibacillus sp.GTY) were selected to treat acid red B or acid scarlet GR contaminated water. Results showed that Medicago sativa L. was more tolerant to the azo dyes and more helpful in promoting the azo-dye wastewater bio-decoloration than Sesbania cannabina Pers, but GTY density was higher in the root exudates of Sesbania cannabina Pers than that of Medicago sativa L. This indicated that the increase of GTY density only partially presented the azo-dye decolorization promoted by plants.

Adsorption Behavior of Organically Modified Bentonite for Acid Brilliant Scarlet GR

Organically modified bentonite was prepared by using hexadecyl trimethyl ammonium bromide (HDTMA) under ultrasonic conditions in this experiment. The modified bentonite was used to treat the acid brilliant scarlet GR and the adsorption behavior was investigated. The results indicated that the adsorption isotherm data were well fit for the Langmuir isotherm model and the pseudo two-order adsorption kinetics equation has the highest goodness of fit and the best linear correlation.

Mechanism of interaction of hydrocalumites (Ca/Al-LDH) with methyl orange and acidic scarlet GR

The development of new materials for water purification is of universal importance. Among these types of materials are layered double hydroxides (LDHs). Non-ionic materials pose a significant problem as pollutants. The interaction of methyl orange (MO) and acidic scarlet GR (GR) adsorption on hydrocalumite (Ca/Al-LDH-Cl) was studied by X-ray diffraction (XRD), infrared spectroscopy (MIR), scanning electron microscope (SEM), and near-infrared spectroscopy (NIR). The XRD results revealed that the basal spacing of Ca/Al-LDH-MO was expanded to 2.45 nm, and the MO molecules were intercalated with a interpenetrating bilayer model in the gallery of LDH, with 49° tilting angle. Yet, Ca/Al-LDH-GR was kept the same d-value as Ca/Al-LDH-Cl. The NIR spectrum for Ca/Al-LDH-MO showed a prominent band around 5994 cm −1, assigned to the combination result of the N H stretching vibrations, which was considered as a mark to assess MO − ion intercalation into Ca/Al-LDH-Cl interlayers. From SEM images, the particle morphology of Ca/Al-LDH-MO mainly changed to irregular platelets, with a “honey-comb” like structure. Yet, the Ca/Al-LDH-GR maintained regular hexagon platelets, which was similar to that of Ca/Al-LDH-Cl. All results indicated that MO − ion was intercalated into Ca/Al-LDH-Cl interlayers, and acidic scarlet GR was only adsorbed upon Ca/Al-LDH-Cl surfaces.

Degradation of Refractory Wastewater by Chlorine Dioxide Oxidation

The ClO2 chemical oxidation system and ClO2 catalytic oxidation system are studied in this paper. The results show that pH=6~8, 1000mg ClO2/L wastewater, reacting 60min are the most efficient and economical, when treating Acid Brilliant Scarlet GR dyestuff wastewater, the COD of which is 3500mg/L, by ClO2 chemical oxidation. The COD removal ratio exceeds 50%, and the oxidation index (COD removal amount/ ClO2 used amount) is 2.3. When treating the wastewater by catalytic oxidation which is composed of ClO2 and special catalyst, pH≈2, 800mg ClO2/L wastewater, reacting 45~60min are the most efficient and economical. The COD removal ratio exceeds 80%, and the oxidation index (COD removal amount/ ClO2 used amount) is 3.5. The cost of oxidant removing 1kg COD is ¥3.7. The effect is superior to that of ClO2chemical oxidation apparently. The study indicates that ClO2 catalytic oxidation is an efficient method to treat refractory wastewater and it’ll have a broad prospect.

Adsorption of acid dyes onto bentonite modified with polycations: Kinetics study and process design to minimize the contact time

The adsorption kinetics of two acid dyes, Acid Scarlet GR and Acid Dark Blue 2G, onto a bentonite modified with poly-epichlorohydrin-dimethylamine (EPI-DMA) was studied. The pseudo second-order model showed a high degree of correlation with the experimental data for the whole adsorption process, whereas the intraparticle diffusion model presented two steps with two different diffusion rate constants indicating that the intraparticle diffusion may be involved in the adsorption process during the first 15 min. A two-stage batch adsorber was designed based on the second-order kinetics and was optimized to minimize the total contact time.

Study on Treatment of Acid Scarlet GR Wastewater by Coupling System of K<sub>2</sub>FeO<sub>4</sub> –PAFC

Using Ferrate (K2FeO4) and polymer flocculant PAFC (PAFC) Collaborative approach, deal with the Acid Scarlet GR Wastewater. Study the effect of Ferrate dosage, PAFC dosage, Ferrate dosing time, Wastewater initial pH Value. Results show that Ferrate pre-oxidation can significantly improve the Coagulation for the removal of Acid Scarlet GR. when the initial concentration of Acid Scarlet GR is 25mg/L, Ferrate dosage is 90mg,PAFC dosage is 13mL,the removal of Acid Scarlet GR is 95.67%.pH on Ferrate removal of Acid Scarlet GR wastewater has little effect. When pH value is 4-8, the removal rate can reach more than 92%.When pH value is 5.6,the removal rate is the highest.

3-aminopropyltriethoxysilane functionalized nanoscale zero-valent iron for the removal of dyes from aqueous solution

3-aminopropyltriethoxysilane functionalized nanoscale zero-valent iron for the removal of dyes from aqueous solution Batch studies were conducted to investigate the potential of 3-aminopropyltriethoxysilane modified nano zero-valent iron (APS-NZVI) to adsorb two dyes (acid brilliant scarlet GR and reactive brilliant red K-2BP) from aqueous solution. APS-NZVI showed good adsorption performance for two dyes. Under the adsorption conditions of pH 4.5, initial concentration was 100 mg/L, and time=4h, the maximum adsorption capacities of APS-NZVI were 121.06 mg/g for acid brilliant scarlet GR and 191.5 mg/g for reactive brilliant red K-2BP, respectively. The results revealed that the adsorption behavior of the dyes on the nano-particles fitted well with the Langmuir model and the sorption kinetics fits well the pseudo-second-order rate equation.