Azo Dye Methyl Orange Research Articles

Photocatalytic Activity of Magnetic Nano-β-FeOOH/Fe3O4/Biochar Composites for the Enhanced Degradation of Methyl Orange Under Visible Light.

A novel nano-β-FeOOH/Fe3O4/biochar composite with enhanced photocatalytic performance and superparamagnetism was successfully fabricated via an environmentally friendly one-step method. The structural properties of the prepared composite were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, and a vibrating sample magnetometer. The XPS spectrum of the as-prepared composites confirmed the presence of Fe-O-C bonds between β-FeOOH and biochar, which could be conducive to transfer photo-generated electrons. UV-vis spectroscopy confirmed the existence of an electron–hole connection between β-FeOOH and biochar, which promoted the rapid interface transfer of photogenerated electrons from β-FeOOH to biochar. These novel structures could enhance the response of biochar to accelerate the photoelectrons under visible light for more free radicals. Electron spin resonance analysis and free radical quenching experiments showed that •OH was the primary active species in the photodegradation process of methyl orange by nano-β-FeOOH/Fe3O4/biochar. In the synergistic photocatalytic system, β-FeOOH/Fe3O4/biochar exhibited excellent catalytic activity for the degradation of azo dye (methyl orange), which is 2.03 times higher than that of the original biochar, while the surface area decreased from 1424.82 to 790.66 m2·g−1. Furthermore, β-FeOOH/Fe3O4/biochar maintained a stable structure and at least 98% catalytic activity after reuse, and it was easy to separate due to its superparamagnetism. This work highlights the enhanced photocatalytic performance of β-FeOOH/Fe3O4/biochar material, which can be used in azo dye wastewater treatment.

Simultaneous bioremediation of cationic copper ions and anionic methyl orange azo dye by brown marine alga Fucus vesiculosus

Textile wastewater contains large quantities of azo dyes mixed with various contaminants especially heavy metal ions. The discharge of effluents containing methyl orange (MO) dye and Cu2+ ions into water is harmful because they have severe toxic effects to humans and the aquatic ecosystem. The dried algal biomass was used as a sustainable, cost-effective and eco-friendly for the treatment of the textile wastewater. Box–Behnken design (BBD) was used to identify the most significant factors for achieving maximum biosorption of Cu2+ and MO from aqueous solutions using marine alga Fucus vesiculosus biomass. The experimental results indicated that 3 g/L of F. vesiculosus biomass was capable of removing 92.76% of copper and 50.27% of MO simultaneously from aqueous solution using MO (60 mg/L), copper (200 mg/L) at pH 7 within 60 min with agitation at 200 rpm. The dry biomass was also investigated using SEM, EDS, and FTIR before and after MO and copper biosorption. FTIR, EDS and SEM analyses revealed obvious changes in the characteristics of the algal biomass as a result of the biosorption process. The dry biomass of F. vesiculosus can eliminate MO and copper ions from aquatic effluents in a feasible and efficient method.

Efficient and easily retrievable green modified carboxymethyl cellulose coated A. indica stem bark encapsulated metal nanoparticles towards the reduction of o-nitrophenol and azo dyes

A new type of economically feasible and environmental-friendly Azadirachta indica stem bark (AIB)/sulfated carboxymethyl cellulose (AIB/S-CMC) based bio-composite catalysts decorated with efficient zero-valent metal nanoparticles were fabricated through an easy and fast chemical approach. First of all, sodium salt of carboxymethyl cellulose (CMC) was modified into sulfated-CMC (S-CMC) by a non-toxic sulfating agent followed by dip coating on AIB pellets. The AIB/S-CMC bio-composites decorated with M0 = Ag, Co, Cu, Ni, Ag-Co, and Cu-Co(M0-AIB/S-CMC) were analyzed by different techniques such as FE-SEM, EDAX, UV–Vis, XRD, and FTIR, which confirmed that the metal nanoprticles were successfully synthesized and well dispersed on the surface of fabricated bio-composite catalysts. The M0-AIB/S-CMC bio-composites were then subjected to extensive evaluation and investigation of its potential ability as efficient catalyst for reduction of 2-nitrophenol (2-NP) and toxic dyes. The results demonstrated that Co-AIB/S-CMC bio-composite catalyst exhibits good stabilities and catalytic activities for the reduction of 2-NP and azo dyes (acid red and methyl orange). Despite of having a good catalytic ability, Co-AIB/S-CMC bio-composite catalysts could be easily recoverable from aqueous media after completion of the reaction simply by pulling the pellets from the reaction matrix.

Green iron oxides/amino-functionalized MCM-41 composites as adsorbent for anionic azo dye: Kinetic and isotherm studies

In this work, green iron oxide nanoparticles (FeONPs) were prepared from Fe(III) precursor and Camellia sinensis (black tea) extract, and were anchored on amino-functionalized mesoporous silica MCM-41. The multicomponent composite named BTFe/MCM-41-NH2 was characterized and applied in the adsorption of the anionic azo dye methyl orange. The results indicated that BTFe/MCM-41-NH2 is 11 times more adsorbent than MCM-41 and 2.5 times more adsorbent than MCM-41-NH2, showing the improved adsorption property of the multifunctional material. Adsorption parameters such as adsorbent dosage, initial dye concentration, pH and time, were screened for BTFe/MCM-41-NH2, a provided an experimental adsorption capacity at equilibrium of qe,exp = 105.3 mg g−1 at 298 K. Zeta potential measurements showed the favored electrostatic interaction with the negatively charged dye at acid pH when BTFe/MCM-41-NH2 is positively charged. Kinetic studies revealed pseudo-first-order model characteristic of reaction-controlled adsorption. The experimental data at equilibrium was fit by several adsorption isotherms models. Freundlich and Temkin were the most suitable isotherms to describe the prepared material, suggesting an adsorption through a heterogeneous surface with multiple sites of adsorption, such as protonated amino groups, FeONPs, besides the tea polyphenols that provided extra sites of adsorption through π-π interactions with the aromatic rings of the dyes.

СІНТЕЗ І ФОТОКАТАЛІТИЧНІ ВЛАСТИВОСТІ КОМПОЗИЦІЙНИХ ПОКРИТТІВ НА ОСНОВІ КОБАЛЬТУ З ТУГОПЛАВКИМИ КОМПОНЕНТАМИ

The possibility of electrosynthesis and control of the surface composition and morphology of the electrolytic cobalt coatings with refractory metals by varying the parameters of electrolysis has been proved. It was found that oxygen and carbon are included in the composition of the coatings as well as the main components, thus such systems can be considered as composite. The coatings deposited by pulsed current can be considered as composite materials the oxide phase for which is formed directly in the electrode process as an intermediate of incomplete reduction of tungstates and hydrolysis of zirconium (IV) salts. The topography of the films is distinguished by the presence of elliptical and spherical grains with crystallite sizes of 80 - 180 nm. On the surface of the coatings, there are hills (large grains) with a diameter of 1 - 3 μm. The fractal dimension of the surface is 2.77, which indicates the 3D mechanism of crystal growth during the formation of coatings. In terms of phase composition, composites are predominantly amorphous materials that contain nanocrystalline cobalt and the intermetallic compound Co3W and Zr3Co. The study of the morphology and topography of the composite coatings surface, as well as its quantitative and phase composition, indicates the possibility of photocatalytic activity of the Co-Mo-WOх, Co-Mo-ZrO2 and Co-W-ZrO2 coatings. Investigation of the photodegradation of the azo dye methyl orange found that the efficiency of MO removal from the solution was 24%, 18%, and 10% for 30 min of ultraviolet irradiation in the presence of Co-Mo-WOх, Co-Mo-ZrO2 and Co-W-ZrO2 on composite coatings, respectively. The higher photoactivity of Co-Mo-WOx composite coatings can be explained by the presence of non-stoichiometric molybdenum and tungsten oxides.

High-efficiency degradation of the azo dye methyl orange using Co-Mn/ZrO2 via catalytic ozonation process

High-efficiency degradation of the azo dye methyl orange using Co-Mn/ZrO2 via catalytic ozonation process

Role of Nanocrystallites of Al-Based Glasses and H2O2 in Degradation Azo Dyes.

Al-based metallic glasses have a special atomic structure and should have a unique degradation ability in azo dye solutions. The Al88Ni9Y3 (Y3), Al85Ni9Y6 (Y6) and Al82Ni9Y9 (Y9) glassy ribbons are melt spun and used in degrading methyl orange (MO) azo dye solution with adding H2O2. With increasing cY, the as-spun ribbons have an increasing GFA (glass formability) and gradually decreased the degradation rate of MO solution. TEM (transmission electron microscopy) results show that the Y3 ribbon has nano-scale crystallites, which may form the channels to transport elements to the surface for degrading the MO solution. After adding H2O2, the degradation efficiency of Al-based glasses is improved and the Y6 ribbon has formed nano-scale crystallites embedded in the amorphous matrix and it has the largest improvement in MO solution degradation. These results indicate that forming nano-scale crystallites and adding H2O2 are effective methods to improve the degradation ability of Al-based glasses in azo dye solutions.

Green palladium nanoparticles prepared with glycerol and supported on maghemite for dye removal application

This study aims to synthesize palladium nanoparticles (PdNPs) in presence of glycerol as green reducing/stabilizing agent, supported on γ-Fe2O3 (maghemite), as catalysts for dye removal. Three materials were prepared with different Pd loadings, from 0.43 to 0.63 wt%. PdNPs at the surface were composed of Pd0, Pd2+ and Pd4+ species, at average oxidation state of +1.6 and Pd2+:Pd0 atomic ratio up to 1:0.9, which showed that glycerol was able to partially reduce Pd2+. PdNPs of spherical shaped clumps morphology, predominantly well dispersed on the γ-Fe2O3 surface were formed. High resolution scanning transmission electron microscopy images of the materials with higher Pd content revealed PdNPs smaller than 5 nm with crystal interplanar distance compatible with Pd(0). The catalysts were applied in the adsorption as well as in the heterogeneous Fenton degradation of the azo dye methyl orange with 90% of decolourization after 240 min. It was possible to observe an improvement in the catalytic activity with the Pd content increase as well as with the PdNPs size distribution. The dye removal followed pseudo-first-order kinetics. The effect of catalyst dosage and temperature were evaluated. The acidic character of the iron compounds as well as of the glycerol acidic hydrogens constituents of the catalyst can be released in the reaction medium, being responsible to adjust the reaction pH to 3, which is the optimum pH for Fenton process.

Removal of Azo Dye Methyl Orange in Aqueous Solution by Kaolinite Clay: Equilibrium Isotherms, Kinetics and Error Analyses

Removal of Azo Dye Methyl Orange in Aqueous Solution by Kaolinite Clay: Equilibrium Isotherms, Kinetics and Error Analyses

Decolorization, degradation and detoxification of carcinogenic sulfonated azo dye methyl orange by newly developed biofilm consortia.

Metabolites of azo dyes are often carcinogenic, teratogenic, mutagenic and recalcitrant in nature. In this study, four biofilm consortia such as C1 (Vitreoscilla sp. ENSG301, Acinetobacter lwoffii ENSG302, Klebsiella pneumoniae ENSG303 and Pseudomonas fluorescens ENSG304), C2 (Escherichia coli ENSD101, Enterobacter asburiae ENSD102 and E. ludwigii ENSH201), C3 (E. asburiae ENSD102, Vitreoscilla sp. ENSG301 and Bacillus thuringiensis ENSW401), and C4 (E. coli ENSD101, E. ludwigii ENSH201 and B. thuringiensis ENSW401) were applied to degrade and detoxify methyl orange (MO), a carcinogenic, sulfonated mono azo dye, used in textile dyeing industry worldwide. The consortia of C1, C2, C3 and C4 showed 97.30, 98.75, 99.51 and 99.29% decolorization, respectively in yeast extract peptone (YEP) broth containing 200 mg L−1 MO within 60 h of incubation in static condition. The optimum pH and temperature for decolorization was 7.0 and 28 °C, respectively. Some divalent metal ions including Mg2+, Ca2+, Zn2+ and Mn2+ could stimulate MO decolorization. UV–Vis spectral analysis showed that the absorption peak at 465 nm originated from the azo (N Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> N) bond was completely disappeared within 60 h of incubation. Fourier transform infrared spectroscopy (FTIR) results also revealed that several major peaks including azo bond peak at 1602.6 cm−1 are completely or partly vanished, deformed or shifted. Activities of azoreductase, NADH-DCIP reductase and laccase were significantly increased in the bacterial cells within 60 h of incubation in comparison to that of control (0 h). The chemical oxygen demand was incredibly reduced by 85.37 to 91.44% by these consortia. Accordingly, plant (wheat seed germination) and microbial (growth of the plant probiotic bacteria such as Pseudomonas cedrina ESR12 and Bacillus cereus ESD3 on biodegraded products) toxicity studies showed that biodegraded products of MO are non-toxic. Thus, all these consortia can be utilized in bioremediation of MO from wastewater for safe disposal into environment. To our knowledge, this is the first report on degradation and detoxification of MO from wastewater by bacterial biofilm consortia.

PLASMA-ASSISTED ADVANCED OXIDATION PROCESS AND NOVEL MATERIALS FOR WATER AND WASTEWATER TREATMENT

The rapid growth in world population brings with it the need for improvement in the current technology for water purification, in order to provide adequate potable water to everyone. The plasma-based advanced oxidation process (AOP) is one of the most widely studied and best developed processes owing to its environmental compatibility, simple structure, efficiencies and ease of operation. In this study, a plasma-based AOP was stably generated using contact non-equilibrium low-temperature plasma and plasma synthesized composite nanomaterials (TiO2/Ag NPs) for water and wastewater purification. The degradation efficiency of the pollutants was determined by UV–Vis absorption spectroscopy. It was found that, due to the simultaneous production of highly reactive species, plasmas can efficiently eliminate pollutants that are difficult to remove using conventional methods. Aqueous solutions of various pollutants were treated by a low-pressure discharge. Experimental results indicated that CNP was effective for degradation azo dye pollutants (methylene blue (MB) and methyl orange MO) and antibiotics (ofloxacin (OFX) and ciprofloxacin (CFX)): МВ and МО were degraded by 98.5% and 97.0%, respectively after 3 min of plasma treatment; OFX and CFX were degraded by ~95.0% and 80.0%, respectively AOP by CNP indicated. The photodegradation of methylene blue catalyzed by plasma synthesized TiO2/Ag was studied under UV irradiation. The degradation (~91%) was obtained with 2.4 g/L TiO2/Ag within 90 min irradiation.

Effect of molecular weight of PEG polymer matrix on the diffraction efficiency of Methyl Orange holographic media

Abstract Recording media for diffraction gratings formation based on polymer films of polyethylene glycol doped with the photoisomerisable azo-dye Methyl Orange have been developed. Holographic recording of the plane wave front for parallel and orthogonal orientation of polarization vectors of light beams have been performed at room temperature. In order to optimize the recording conditions and obtain high-efficient polarization holographic gratings, in the present work we study the dependence the average molecular weight of polymer matrix and solvent system for thin layers formation on the diffraction efficiency. Five PEG polymers were used as host for azo-dye incorporation −1500, 4000, 6000, 10,000 and 40,000, and two solvent systems, EtOH–H2O and THF-H2O, were examined to investigate film-forming properties. It was concluded, that structure of films as well as diffraction efficiency value and curves character strongly depend on PEG molecular weight.

Application of copper tailings combined with persulfate for better removing methyl orange from wastewater.

In this paper, wasted copper tailings (CT) were used to activate persulfate (PS) to degrade azo dye methyl orange (MO). The results show that a large amount of FeS2 contained in CT can slowly release Fe2+ in the aqueous solution to activate PS to generate reactive oxygen species to degrade MO. When the dosage of CT and PS was 2 g/L and 3 mM respectively, the MO degradation efficiency of 20 mg/L in the CT/PS system was 96.52% within 60 min. At the same time, it is found that CT has a certain adsorption capacity for MO, and the intra-particle diffusion model can well describe the adsorption process of MO by CT. The effects of related reaction parameters (CT dosage, PS dosage, initial MO concentration and solution pH) on MO degradation in CT/PS system were investigated. Compared with the direct addition of an equal amount of Fe2+ as in the CT/PS system, for homogeneous activated PS to degrade MO (Fe2+/PS), the results showed that the degradation efficiency of Fe2+/PS system for MO was lower than that of CT/PS system due to excessive Fe2+ consumption of SO4 ·-. By comparing the Fe2+ and Fe3+ concentrations in the two systems, it was found that the CT/PS system could maintain a low Fe2+ concentration during the reaction process, and the Fe2+ released by CT could be used by PS to degrade MO more efficiently. The free radical scavenging experiments showed that the reactive oxygen species in the CT/PS system was mainly SO4 ·-. This study not only proposed a new CT utilization approach, but also solved the problem of reduced degradation efficiency of organic pollutants caused by excessive Fe2+ in the Fenton-like reaction.

Application of Central Composite Design to the Photo Fenton Degradation of Methyl Orange Azo Dye Using Fe-Activated Carbon Catalyst

Photo-fenton oxidation technique is one of the emerging oxidation processes explored in treatment of organic pollutants in aqueous solutions. This research is focused on utilization of Fe(II) loaded activated carbon and H2O2(aq) in a photofenton process to generate hydroxyl radicals that mineralize methyl orange dyes. Samples of activated carbon were treated with Fe(NO3)2(aq) and characterized using SEM, pHZPC, specific surface area and boehm’s titration. The degradation of methyl orange by the iron loaded activated carbon (Fe-Ac), via photo-Fenton process, was investigated in lab-scale defined by experimental design. Central composite design (CCD) was used to evaluate the effects of the five independent variables considered for the optimization of the oxidative process: time, FeAc dose, methyl orange concentration, pH and H2O2 concentrations. In the optimization, the correlation coefficients (R2 ) for the quadratic model was 0.9941. Optimum reaction conditions were obtained at pH = 3, catalyst dose = 0.1 mg/100ml, H2O2 = 0.62ml, methyl orange concentration = 5mg/l and time = 30 minutes.

Batch Studies for the Removal of a Hazardous Azo Dye Methyl Orange from Water through Adsorption on Regenerated Activated Carbons

Batch Studies for the Removal of a Hazardous Azo Dye Methyl Orange from Water through Adsorption on Regenerated Activated Carbons

Mineralization of Methyl Orange azo dye by processes based on H2O2 electrogeneration at a 3D-like air-diffusion cathode

This work addresses the mineralization of the widely used Methyl Orange (MO) azo dye by technologies based on H2O2 electrogeneration at a 3D-like air-diffusion cathode. These include two Fe2+-catalyzed processes such as electro-Fenton (EF) and photoelectro-Fenton (PEF). Bulk electrolyses were performed in a recirculation flow plant, in which the Eco-Cell filter-press electrochemical reactor was connected in series with a UVA photoreactor. The former reactor was equipped with a Ti|Ir–Sn–Sb oxide plate anode alongside a 3D-like air-diffusion cathode made from graphite felt and hydrophobized carbon cloth, aimed at electrogenerating H2O2 on site. The influence of current density (j), volumetric flow rate (Q) and initial MO concentration was examined. The greatest oxidation power corresponded to PEF process. The best operation conditions to treat 30 mg L−1 of total organic carbon of MO in a 50 mM Na2SO4 solution by PEF were found at 0.50 mM Fe2+, pH 3.0, j = 20 mA cm−2 and Q = 2.0 L min−1, obtaining 100% and 94% of color and TOC removals at 30 and 240–300 min, respectively. This accounted for 35% of mineralization current efficiency and 0.12 kWh (g TOC)−1 of energy consumption at the end of the electrolysis. The oxidation power of EF and PEF was compared with that of anodic oxidation (AO), and the sequence obtained was: PEF > EF > AO. The dye was gradually degraded, yielding non-toxic short carboxylic acids, like maleic, fumaric, formic, oxalic and oxamic, whose Fe(III) complexes were rapidly photolyzed.

Kinetic study of methyl orange decolorization by the Fenton process based on fractional factorial design

In this study, a correlation of kinetic parameters was established for the decolorization of a methyl orange (MO) azo dye by Fenton oxidation. The experiments were carried out in a batch reactor at room temperature and the operating conditions were optimized using the 24−1 fractional factorial design. Each of the selected factors, i.e. the initial concentration of the MO dye, the catalyst dosage (Fe2+), the initial concentration of H2O2 and the pH of the solution, were varied on two levels. Regressions equations were constructed by relating the parameters of dye oxidation rate in aqueous phase (the initial rate Vi, the rate constant k and the maximum yield by unit time) to four operating conditions. MO dye decolorization profiles as a function of time were satisfactorily adjusted for the majority of the experiments by second-order kinetics on the Levenberg Marquart algorithm using Minitab 17. The validation of the model equations, carried out by the Analysis of Variance (ANOVA), showed that these equations explain about 98% of the variability of the responses and that these simple linear models should cover 92% of the future responses. It has been shown that there is robust relationship between the dynamic behaviour of this process at the initial time and the maximum yield of decolorization at steady state with dye concentration and hydrogen peroxide.

Hierarchical BiOHC2O4/Bi2O2CO3 composite microrods fabricated via insitu anion ion-exchange and their advanced photocatalytic performance

Abstract BiOHC2O4 microrods as the template were first synthesized via a facile microwave hydrothermal method. Then, BiOHC2O4/Bi2O2CO3 microrods and Bi2O2CO3 nanosheets with hierarchical structure were in-situ synthesized at room temperature by carbonate ion-exchange using BiOHC2O4 crystals as a template. The obtained hierarchical BiOHC2O4/Bi2O2CO3 microrods and Bi2O2CO3 nanosheets displayed superior texture properties in aqueous photocatalytic reactions, e.g. low density, large specific surface area and good dispersion. Therefore, these hierarchical BiOHC2O4/Bi2O2CO3 microrods possessed excellent photocatalytic activity for azo dye methyl orange (MO) degradation. The reason for the high photocatalytic performance of BiOHC2O4/Bi2O2CO3 microrods could be due to their unique interface which endows with efficient light harvesting capability and high carrier separation and utilization. Radical capture test confirmed that more h+ and ·O2− were produced over this unique hierarchical BiOHC2O4/Bi2O2CO3 heterojunction. A possible reaction pathway involved two-electrons reduction of oxygen for promoting photocatalytic degradation efficiency of MO was proposed.

Studies on the Antibacterial and Catalytic Activities of Silver Nanoparticles Synthesized from Cyperus rotundus L.

The present report demonstrates a simple and green biosynthesis of silver nanoparticles (AgNps) using the extract of the rhizome of Cyperus rotundus L., a native plant having some medicinal importance. The antibacterial activity of AgNps on Escherichia coli, a Gram-negative bacterium as well as the catalytic activity of AgNps for degradation of azo dyes was investigated. The inhibition of the cell growth of Escherichia coli was found to occur in 18 h corresponding to AgNps concentration of 7.2 μg mL−1, considered as the minimum inhibitory concentration. The 99.9% cell killing was achieved in 18 h on treatment with AgNps at a concentration of 7.8 μg mL−1, considered as minimum bactericidal concentration. The Escherichia coli cell filamentation was observed when treated with AgNps. The bactericidal activity of Escherichia coli is thought to be due to the cell death via AgNps concentration dependent reactive oxygen species production. The catalytic activity of AgNps for degradation of azo dyes (methyl orange, methyl red and congo red) in presence of sodium borohydride was also investigated. Almost 95% dye degradation occurred in few minutes using AgNps and nil without AgNps. The degradation pathway follows pseudo first order kinetics. The activation energy for dye degradation was calculated.

3D Printing of Living MFC Anode

3D printing helps to provide further control on electrode design. By using 3D printing to tune the geometry, porosity and dimensions of the structure, mass transport to functional microbes or sites in the structure can be improved. By embedding living microbes directly into the ink we can create 3D printed structures to help harness the activity of microbes and use them in functional devices. Here we demonstrate the incorporation of the living bacteria Shewanella Oneidensis MR-1 (S. Oneidensis MR-1) directly into an ink used for creating 3D printed structures. By incorporating S. Oneidensis MR-1 into a sodium alginate-cellulose ink we showed that S. Oneidensis MR-1 survives the 3D printing process through the prominent degradation of methyl orange azo dye from the surrounding solution in the presence of the living 3D printed structure. The viability was further confirmed using confocal microscopy. By incorporating carbon black into this ink we further demonstrate the direct printing of a living microbial fuel cell (MFC) anode. Electrochemical measurements showed there was good charge transfer between the S. Oneidensis MR-1 and the electrode surface. To our knowledge, this is the first report on implementing 3D printed bacteria structure as a living electrode for an MFC system. The capability of printing living and functional 3D bacterial structure could open up new possibilities in design and fabrication of microbial devices as well as fundamental research on the interaction between different bacterial strains, electrode materials, and surrounding environments.