Azo Dye Congo Red Research Articles

Biodegradation Pathway of Congo Red azo dye by Geotrichum candidum and Toxicity Assessment of Metabolites

Biodegradation Pathway of Congo Red azo dye by Geotrichum candidum and Toxicity Assessment of Metabolites

Facile one-step synthesis and characterization of MnO nanoneedles and their application in solar photocatalysis

Manganese oxide (MnO) colloidal nanoneedles have been successfully synthesized by a facile one-step method based on the alkaline reaction of the precursor manganese acetate salt and excess sodium hydroxide. X-ray diffraction and FT-IR spectroscopy confirmed the synthesized MnO nanoneedles phase and structure. The optical properties of synthesized MnO nanoneedles were studied by UV–Vis absorption spectroscopy. Optical particle size and band gap of synthesized MnO colloidal nanoneedles were calculated. HR-TEM/SEM images and EDX allow us to determined particle shape and size. The photocatalytic activity of the MnO nanoneedles was evaluated using the Congo red azo dye in an aqueous solution under solar light irradiation. The results showed that nanoneedles, compared with commercial ZnO nanoparticles, exhibited high photocatalytic activity. The photocatalytic studies also showed that various parameters such as band gap, size, shape, and rate constant velocity remarkably affected the remotion rate of Congo red azo dye.

Sorption Behavior of Azo Dye Congo Red onto Activated Biochar from Haematoxylum campechianum Waste: Gradient Boosting Machine Learning-Assisted Bayesian Optimization for Improved Adsorption Process.

This work aimed to describe the adsorption behavior of Congo red (CR) onto activated biochar material prepared from Haematoxylum campechianum waste (ABHC). The carbon precursor was soaked with phosphoric acid, followed by pyrolysis to convert the precursor into activated biochar. The surface morphology of the adsorbent (before and after dye adsorption) was characterized by scanning electron microscopy (SEM/EDS), BET method, X-ray powder diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) and, lastly, pHpzc was also determined. Batch studies were carried out in the following intervals of pH = 4-10, temperature = 300.15-330.15 K, the dose of adsorbent = 1-10 g/L, and isotherms evaluated the adsorption process to determine the maximum adsorption capacity (Qmax, mg/g). Kinetic studies were performed starting from two different initial concentrations (25 and 50 mg/L) and at a maximum contact time of 48 h. The reusability potential of activated biochar was evaluated by adsorption-desorption cycles. The maximum adsorption capacity obtained with the Langmuir adsorption isotherm model was 114.8 mg/g at 300.15 K, pH = 5.4, and a dose of activated biochar of 1.0 g/L. This study also highlights the application of advanced machine learning techniques to optimize a chemical removal process. Leveraging a comprehensive dataset, a Gradient Boosting regression model was developed and fine-tuned using Bayesian optimization within a Python programming environment. The optimization algorithm efficiently navigated the input space to maximize the removal percentage, resulting in a predicted efficiency of approximately 90.47% under optimal conditions. These findings offer promising insights for enhancing efficiency in similar removal processes, showcasing the potential of machine learning in process optimization and environmental remediation.

Effective adsorption of fluorescent congo red azo dye from aqueous solution by green synthesized nanosphere ZnO/CuO composite using propolis as bee byproduct extract.

The indirect dumping of massive volumes of toxic dyes into water has seriously affected the ecosystem. Owing to the many applications of the designed nanomaterials in the manufacturing process, there is a lot of research interest in synthesizing nanomaterials using green processes. In this research, the byproduct of bee was employed to synthesize nanoparticles (NPs) of ZnO, CuO, and biosynthesized ZnO/CuO (BZC) nanocomposite via utilizing a green and simple approach. To validate the effective fabrication of BZC nanocomposite, various characterization measurements were applied. FTIR analysis identified the functional groups in charge of producing nanoparticles and nanocomposites. Moreover, the existence of ZnO and CuO XRD peaks suggests that the nanocomposites were successfully biosynthesized. The high-resolution XPS spectrum of the BZC nanocomposite's Zn2p3, Cu2p3, and O1s were observed. Our findings indicate the successful engineering of the prepared nanomaterials and BZC nanocomposite. Our findings indicate the successful engineering of the prepared nanomaterials and BZC nanocomposite. For Congo red (CR) fluorescent stain azo dye elimination in water, all adsorption parameters were examined at room temperature. Moreover, the adsorption experiments revealed the removal capacity for uptake CR dye using BZC nanocomposite (90.14mgg-1). Our results show that the BZC nanocomposite exhibited high removal capability for the adsorption of CR dye. The nanosphere adsorbent offered a simple, low-cost, and green approach for water purification and industrial wastewater control.

Modeling the Degradation Rate of the Azo Dye Congo Red by Acinetobacter baumannii

One of the challenges that face the textile industry is the release of effluents that are not wanted, most notably colors that do not degrade. This is one of the issues that plagues the industry. This is a concern since it affects the environment. Bioremediation using dye-degrading bacterium is appealing as bacterial metabolism converts hazardous dye to harmless carbon dioxide and water as byproducts. In this study, various secondary growth models such as Luong, Yano, Teissier-Edward, Aiba, Haldane, Monod, Han, and Levenspiel were employed. Following thorough statistical analyses such as root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), and accuracy factor (AF), the Luong model emerged as the most optimal choice. The half-saturation constant for maximal growth, maximal growth rate and maximal concentration of substrate tolerated and curve parameter that defines the steepness of the growth rate decline from the maximum rate symbolized by Ks, qmax and Sm, and n were 76.54 mg/L (95% C.I., 50.51 to 102.57), 0.240 per h (95% C.I., 0.219 to 0.270), 1135.37 mg/L (95% C.I., 1041.04 to 1229.72) and 5.34 (95% C.I., 2.36 to 8.32), respectively. These novel constants discovered during the modeling process could serve as valuable inputs for subsequent modeling pursuits.

Facile synthesis of novel CoWO4/FeWO4 hetrocomposite with efficient visible light photocatalytic degradation and hydrogen evolution aspects

ABSTRACT Tungstate-based nanomaterials exhibit efficient photocatalytic performance and offer several advantages owing to their electrical and superior optical features, charge transport potentials, and superb corrosion resistance. The objective of the present study is to fabricate cobalt tungstate (CoWO4), Ferric tungstate (FeWO4) and CoWO4/FeWO4 heterojunction composite photocatalysts using a hydrothermal route with various molar concentrations (2:1, 1:1, 1:2, 1:5). The model pollutant Methyl Orange (MO) and Congo Red (CR) azo dyes were degraded 98.26% and 99.61% in 150 min by the as-synthesized CoWO4/FeWO4 at a molar concentration ratio of 1:2. A feasible photodegradation mechanism is purposed and the optimum values for different parameters are also evaluated by considering two different dyes as model organic pollutants. Hydrogen production efficiency reaches up to 36 μmolg−1 h−1 under visible light over 1:2 CoWO4/FeWO4. This work may open new possibilities for the use of CoWO4/FeWO4 composite for potential applications such as the hydrothermal synthesis of composites and their photocatalytic wastewater remedy and as hydrogen evolution applications.

Synthesis of porous calcium-guar gum benzoate nano-biohybrids for sorptive removal of congo red and phosphates from water

This work aims to develop an eco-sound nano-bio-hybrid sorbent using sustainable materials for sorptive elimination of congo red and phosphates from aquatic environment. An amphipathic biopolymer derivative, high DS guar gum benzoate (GGBN) was used for entrapment of as synthesized calcium carbonate nanoparticles using solvent diffusion nano-precipitation technique. Designer nano-biohybrids were developed upon experimenting with various materials stoichiometry. SEM, XRD and EDX studies confirmed near-uniform impregnation of rhombohedral calcium carbonate crystals throughout the biopolymer matrix. Average pore size distribution and surface area of final product Ca-GGBNC, were estimated from NDLFT and BET methods respectively. Analysis of adsorption findings acquired at study temperature 27 ± 2 °C showed that the maximum adsorption capacity of Ca-GGBNC recorded qmax, 333.33 mg/g for congo red azo dye and that for phosphate was at 500 mg/g. Adsorptive removal was noted and both components followed pseudo second order kinetics. Intra-particle diffusion kinetics investigation disclosed that the boundary layer effect was prominent and the adsorption rates were not solely directed by the diffusion stage. Activation energy, Ea was to be estimated using Arrhenius equation at 56.136 and 47.015 KJ/mol for congo red and phosphates respectively. The calculated thermodynamic parameters(ΔG°, ΔH°, and ΔS°) revealed the spontaneous, feasible and endothermic sorption process. Owing to active surface area, spherical size, functional moiety and porous network, antibacterial properties of nanobiohybrid were persistent and MIC against E. coli and S. aureus were recorded at 200 μg/mL and 350 μg/mL respectively.

Enzymatic degradation of azo dyes methylene blue and congo red with peroxidase purified from cauliflower using affinity chromatography technique: Kinetic study, optimization and metal binding activity

The effective results of the enzymatic decolorization of industrial azo dyes found in wastewater, which cause serious health and environmental problems, with peroxidases have recently increased the interest in these enzyme sources. Redox-mediated decolorization of Methylene Blue and Congo Red azo dyes with cauliflower (Brassica oleracea var. botrytis L.) peroxidase (CPOD) purified in one step using 4-amino 3-bromo 2-methyl benzohydrazide molecule was investigated for the first time. The inhibition effect of this molecule, which is used as a ligand in affinity chromatography, on the CPOD enzyme was investigated. The Ki and IC50 values for this enzyme were calculated as 0.113 ± 0.012mM and 0.196 ± 0.011mM, respectively. With the affinity gel obtained by binding to the Sepharose-4B-l-tyrosine matrix of this molecule, which shows a reversible inhibition effect, the purification values of CPOD enzyme were determined as 562-fold with a specific activity of 50,250 Umg-1. The purity of the enzyme was checked by the SDS-PAGE technique and its molecular weight was determined. A single band at 44kDa was observed for the CPOD enzyme. In dye decolorization studies, the effects of dye, enzyme, and hydrogen peroxide concentrations as well as time, pH, and temperature were investigated. The profiles of the optimum conditions for both dyes were similar, and the percentages of decolorization of Methylene Blue and Congo Red under these conditions were 89% and 83%, respectively, at the end of the 40min reaction time. Again, when examining the effect of metal ions on enzyme activity, it was found that there was no significant negative change in CPOD.

Activation of persulfate by heat, FeNPs, and Fe/MnO2 for the advanced oxidation processes

In this work, we used only persulfate (S2O82−), Fe0/S2O82−, Fe/MnO2/S2O82− systems as an activator to generate reactive radical species for the chemical oxidation of Congo red azo dye. The formation of a new colored species at 363 nm and its decomposition was observed at a specific reaction condition for the first time. Congo red-S2O82− redox reaction was very slow at 22 °C. After the addition of small amount of Fe/MnO2, the red color was decolorized completely within 6 min. The maximum degradation of Congo red was achieved at optimum parametric values of [S2O82−] = 0.2 mM, [Congo red] = 0.6 mM, amount of Fe/MnO2 = 10 mg, pH = 6.5, and temperature = 22 °C. The presence of MnO2 accelerates the generation of sulfate radicals (SO4−•) during the Fenton- like reaction between Fe/MnO2 and S2O82− due to the synergistic effect. The activation energy was found to be 40.1, 48.0, and 92.2 kJ/mol for Fe/MnO2/S2O82−, Fe/S2O82−, and only S2O82−, respectively. The oxidation of Congo red follows complex order kinetics with respect to pH as well as concentrations of S2O82−. Chemical probes experiments with various radical scavengers such as ethanol, tertiary butyl alcohol (TBA), and potassium iodide showed that the SO4−• radicals participate effectively in situ chemical oxidation of Congo red. Cationic cetyltrimethylammonium bromide (CTAB) retarded the persulfate activation by Fe/MnO2 significantly. The morphology of Fe/MnO2 was determined by XRD, EDX, FTIR, SEM, and TEM.

One-Step Hydrothermal Synthesis of Cu2ZnSnS4 Nanoparticles as an Efficient Visible Light Photocatalyst for the Degradation of Congo Red Azo Dye.

A hydrothermal method was successfully employed to synthesize kesterite Cu2ZnSnS4 (CZTS) nanoparticles. X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and optical ultraviolet-visible (UV-vis) spectroscopy were used for characterization of structural, chemical, morphological, and optical properties. XRD results confirmed that a nanocrystalline CZTS phase corresponding to the kesterite structure was formed. Raman analysis confirmed the existence of single pure phase CZTS. XPS results revealed the oxidation states as Cu+, Zn2+, Sn4+, and S2-. FESEM and TEM micrograph images revealed the presence of nanoparticles with average sizes between 7 nm to 60 nm. The synthesized CZTS nanoparticles bandgap was found to be 1.5 eV which is optimal for solar photocatalytic degradation applications. The properties as a semiconductor material were evaluated through the Mott-Schottky analysis. The photocatalytic activity of CZTS has been investigated through photodegradation of Congo red azo dye solution under solar simulation light irradiation, proving to be an excellent photo-catalyst for CR where 90.2% degradation could be achieved in just 60 min. Furthermore, the prepared CZTS was reusable and can be repeatedly used to remove Congo red dye from aqueous solutions.

Graphene-Oxide-Grafted Natural Phosphate Support as a Low-Cost Ceramic Membrane for the Removal of Anionic Dyes from Simulated Textile Effluent

A novel natural phosphate/graphene oxide (GO) composite membrane was successfully fabricated using two steps: (i) silane chemical grafting and (ii) dip-coating of a GO solution. First, the low-cost disk ceramic support used in this work was fabricated out of Moroccan natural phosphate, and its properties were thoroughly characterized. The optimized ceramic support was sintered at 1100 °C following a specific heat treatment based on thermogravimetric analysis (TGA) and differential thermal analysis (DTA); it exhibited a permeability of 953.33 L/h·m2·bar, a porosity of 24.55%, an average pore size of 2.45 μm and a flexural strength of 22.46 MPa. The morphology analysis using SEM showed that the GO layer was homogenously coated on the crack-free Moroccan phosphate support with a thickness of 2.8 μm. The Fourier transform infrared spectrometer (FT-IR) results showed that modification with silane could improve the interfacial adhesion between the GO membrane and the ceramic support. After coating with GO on the surface, the water permeability was reduced to 31.93 L/h·m2·bar (i.e., by a factor of 142). The prepared GO/ceramic composite membrane exhibited good efficiency in the rejection of a toxic azo dye Congo Red (CR) (95.2%) and for a simulated dye effluent (87.6%) under industrial conditions. The multi-cycle filtration tests showed that the rejection rate of CR dye remained almost the same for four cycles. Finally, the flux recovery was also studied. After 1 h of water cleaning, the permeate flux recovered, increased significantly, and then remained stable.

Environmental applications of flame synthesized CuO nanoparticles through removal of Congo Red dye

The Copper oxide (CuO) transition metal oxide nanoparticles (NPs) synthesized by simple, fast and commercially viable comfortably slight modified flame pyrolysis method. The CuO NPs were synthesized by direct burning of ethanolic copper chloride solution. The prepared CuO NPs were characterized for phase and crystallinity by X–ray Diffraction [XRD] and Fourier Transform Infrared [FT–IR] Spectroscopy, estimation of morphology was done by Field Emission Transmission Electron Microscopy [FE–SEM], average particles size of prepared CuO NPs estimated by High Resolution Transmission Electron Microscopy [HR - TEM] as well purity ensured by Energy Dispersive X–Ray Spectroscopy [EDS]. UV–vis absorption spectroscopy done for adsorption of aqueous Congo Red (CR) dye of flame synthesized CuO NPs. The structural, elemental and morphological characterization emphasised the synthesized CuO NPs are crystalline, pure and exhibited monoclinic structure with spherical morphology. The environmental applications of these flame synthesized CuO NPs were also evaluated by using adsorption of Congo Red (CR) dye and temperature effect on dye adsorption were also verified. HR-TEM revealed the average particles size of around 30 nm with fringe spacing of 2.788 Å and 2.377 Å, which corresponds to (110) and (200) planes of monoclinic phase of CuO NPs. The synthesized CuO NPs exhibited optical bandgap of 2.93 eV. The synthesized NPs showed high dye removal capacity up to 99.90% for the aqueous solution of Congo Red azo dye. These CuO NPs may emerge as the best catalytic adsorption alternative for the removal of industrial dyes, heavy metals and waste water treatment.

Synthesis, characterization, spectral properties and evaluation of the photophysical behavior of novel Congo Red based polymers

New polyazomethines were synthesized by acid-catalyzed polycondensation of Congo Red azo dye with two dialdehydes to form polymers with azo- and azomethine groups in main chain. Polycondensation proceeded at a reflux temperature in DMF solution with formic acid as a catalyst. Copolymers containing azo- and azomethine groups in main chain were characterized by 1H NMR, FT-IR, and UV–Visible spectrometry, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC). The polymers exhibited photoinduced anisotropy as a result of E-Z photoisomerization. Holograms in thin polymeric films for parallel and perpendicular orientation of the object and reference beams polarization have been recorded. In the case of perpendicular polarization, diffraction efficiencies of the hologram gratings are higher comparing to the parallel. This may be due to the polymer matrix structural rearrangement peculiarities.

Novel ZnO-biochar nanocomposites obtained by hydrothermal method in extracts of Ulva lactuca collected from Black Sea

The aqueous extract of Ulva lactuca, obtained from algae waste, has been used both as precursor for nanobiochar and source of phycocolloids, for obtaining of ZnO@C composites by hydrothermal method, through two synthesis routes, and capped ZnO nanopowders. The nanomaterials were characterized by XRD, SEM, thermal analysis, UV–vis, PL and FTIR spectroscopy. The presence of ZnO with hexagonal wurtzite structure was confirmed by XRD, while the presence of biochar and capping molecules was confirmed by FTIR spectroscopy and thermal analysis correlated with the total organic carbon determination. The band gap energy was calculated from diffuse reflectance spectra. The photocatalytic properties were tested in the degradation of Congo red azo dye under UV and visible light irradiations, the prepared zinc oxide-biochair nanocomposites demonstrating a good photocatalytic activity, superior to the pristine ZnO nanopowders obtained in similar conditions. The results confirmed a good fit with the Langmuir–Hinshelwood kinetic model. A correlation between photoluminescent and photocatalytic properties of nanomaterials was done. The properties of ZnO@C nanocomposites depended on the synthesis route were compared with those of capped and pristine ZnO samples.

Antioxidant, Anti-Bacterial, and Congo Red Dye Degradation Activity of AgxO-Decorated Mustard Oil-Derived rGO Nanocomposites.

Scaling up the production of functional reduced graphene oxide (rGO) and its composites requires the use of low-cost, simple, and sustainable synthesis methods, and renewable feedstocks. In this study, silver oxide-decorated rGO (AgxO−rGO) composites were prepared by open-air combustion of mustard oil, essential oil-containing cooking oil commercially produced from the seeds of Brassica juncea. Silver oxide (AgxO) nanoparticles (NPs) were synthesized using Coleus aromaticus leaf extract as a reducing agent. Formation of mustard seed rGO and AgxO NPs was confirmed by UV-visible characteristic peaks at 258 nm and 444 nm, respectively. rGO had a flake-like morphology and a crystalline structure, with Raman spectra showing clear D and G bands with an ID/IG ratio of 0.992, confirming the fewer defects in the as-prepared mustard oil-derived rGO (M−rGO). The rGO-AgxO composite showed a degradation efficiency of 81.9% with a rate constant k−1 of 0.9506 min−1 for the sodium salt of benzidinediazo-bis-1-naphthylamine-4-sulfonic acid (known as the azo dye Congo Red) in an aqueous solution under visible light irradiation. The composite also showed some antimicrobial activity against Klebsilla pneomoniae, Escherichia coli, and Staphylococcus aureus bacterial cells, with inhibition zones of ~15, 18, and 14 mm, respectively, for a concentration of 300 µg/mL. At 600 µg/mL concentration, the composite also showed moderate scavenging activity for 2,2-diphenyl-1-picrylhydrazyl of ~30.6%, with significantly lower activities measured for AgxO (at ~18.1%) and rGO (~8%) when compared to control.

Structural and XPS studies of polyhedral europium doped gadolinium orthovanadate (Eu3+:GdVO4) nanocatalyst for augmented photodegradation against Congo-red

The present work demonstrates structural, valence band mapping (VBM) and photocatalytic activity of Eu3+ doped orthovanadate (GdVO4) nanosystem against an azo-dye, Congo-red. As evident from x-ray diffraction (XRD) studies, the nanosystem synthesized via a solid-state cum sintering route exhibited zircon-type crystal structure with space group I 41/amd. Imaging through transmission electron microscopy (TEM) has revealed polyhedral nanoaggregates, which are of polycrystalline nature. Introduction of Eu3+ into the host GdVO4 was substantiated from the energy dispersive x-ray (EDX) spectra, x-ray photoelectron spectra (XPS) and considering inclusion of dopants to binding energy correspondence in the VBM spectra. In this study, the azo-dye Congo-red has been opted as the target dye for photodegradation. After UV light illumination, Eu3+:GdVO4 nano-catalyst could degrade the organic dye quite effeciently (up to 91.8%), and offering a rate constant nearly doubled as compared with its undoped counterpart. The dopant ions being associated with the new localized states enabling promotion of additional photoexcited carriers taking advantage of the incident UV exposure. Structural, XPS, and optical studies of the rare-earth vanadate nano-systems as well as their photocatalytic activity would provide new insights to resolve existing concerns, viz., removal of organic contaminants, and environmentally harmful dyes and to carry multi-functional scope for industrial relevance. Moreover, such systems may have immense potential for displaying select emission response as well as photocatalysis even though both processes are mediated via opposite effects.

Separation of dye from aqueous solution by a new gravity compression and aeration system

ABSTRACT Filtration is one of the important technologies for separating suspended particles. Under the condition of gravity compression, the filtration density can be increased and the separation effect of suspended particles can be improved. Considering the complex composition and the difficulty in degrading dye in industrial wastewater, a gravity compression aeration system with a modified polyester fibre ball (denoted as MPFB) was evaluated for the separation of dye from water. Congo red azo dye solution (0–40 mg/L) was selected as the model treatment compound. The MPFB was prepared by adjusting the concentrations of alkali (Quality score 0–25%), β-cyclodextrin (0∼80 g/L), reaction temperature (40–90°C), and silane coupler concentration (Concentration fractions 0–0.8%). We used Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) to characterise the MPFB. The separation was affected significantly by adsorption conditions such as MPFB dose and pH. The lower the MPFB dose, the higher the expected adsorption capacity. For the treatment of a dye solution at 500 mg/L, 100% removal was achieved with 48 g/L MPFB, at pH 8 during adsorption under non-circulation aeration. For 24 h of reaction, the system could reach the maximum adsorption capacity of 11.2 mg/g, which followed the pseudo-first order kinetics model and the intraparticle diffusion model. We discovered that circulation aeration provided the best adsorption and electrostatic and hydrogen bonding were the dominant components of adsorption. Overall, the system is a promising technology and has the potential to treat large volumes of dye wastewater.

PH-dependent effect of Congo Red on the growth of Aspergillus nidulans and Aspergillus niger

The azo dye Congo Red (CR) is frequently used as an agent to elicit cell wall integrity stress in fungi. This highly toxic aromatic, heterocyclic compound contains two azo bonds as chromophore, which are responsible for protonation under acidic conditions, leading to changes in the molecular structure of the dye and the color of the solution. The investigation of how CR affects the growth of Aspergillus nidulans and Aspergillus niger on surface cultures provided us with evidence about its pH-dependent toxicity. Reducing the starting pH of the media from 7 to 3 decreased both the toxicity of CR and the dose-dependence of its toxicity substantially. These changes can be explained by the pH-dependent structural changes of CR and its precipitation at low pH. The pH also depended on the fungi; they could induce a decrease or even an increase, which could be important in the loss of dose-dependence. Our experiments led to the conclusion that in studies to evaluate the antifungal effect of CR, properly buffered solutions with pH values adjusted to above 5 are highly recommended to achieve a well-detectable and dose-dependent antifungal effect. However, for decolorization of CR solutions, lower pH is suggested where the decreased toxicity and solubility of CR could help this process.

Taxonomic diversity and predictive metabolic functions of a heavy metal tolerant multiple azo dye degrading bacterial consortium from textile effluents

Direct disposal of industrial dye effluents is a serious environmental menace. The bacterial population selected in response to dye contamination prominently participate in the dye detoxification process. We report multiple azo dye degradation activity of a bacterial consortium developed in the azo dye Congo Red (CR) supplemented medium. Degradation activity was most effective under static condition. Degradation of CR and other dyes at 2000 mg/L concentration ranged from 85 to 97% after 96–120 h except for Amido Black 10B showing 85% decolorization in 24 h. A 16S rRNA gene metagenomic analysis revealed high abundance of Proteobacteria, Bacteroidetes and Firmicutes in the consortium. The dominant bacterial genus were Acinetobacter, Comamonas, Erwinia, Trichococcus, Dysgonomonas, and Citrobacter. PICRUSt based functional analysis of the metagenome sequences predicted abundance of gene and protein families for mineralization of xenobiotic compounds. The predicted genes were mapped on KEGG pathway for construction of CR degradation pathway.

Co-substrates' influence on bioelectricity production in an azo dye-based microbial fuel cell

Co-substrates have been known to influence bioelectricity output during dye degradation. This preliminary research is focused on understanding the variations of bioelectricity output when co-substrates glucose and nitrogen sources were added along with Congo red azo dye in a double-chambered microbial fuel cell (MFC). A novel bacterial consortium capable of azo dye degradation was added as the inoculant to the double-chambered MFC. Differences in bioelectricity output were noted when glucose alone, ammonium nitrate and ammonium phosphate alone were added as co-substrates with Congo red dye. MFC with 25 mg L−1 ammonium nitrate peaked 0.032V and 0.003A open circuit (OC) output after 8 h hydraulic retention time (HRT). This was followed by observing effects of glucose alone and glucose combined with nitrogen sources over 8 h. Peak voltage and current of 0.11V and 0.012A, respectively were achieved at 3 h HRT by experimental model with glucose alone as co-substrate.