Reactive Black Research Articles

Decolorization of reactive azo dye using novel halotolerant yeast consortium HYC and proposed degradation pathway

The presence of high salinity levels in textile wastewater poses a significant obstacle to the process of decolorizing azo dyes. The present study involved the construction of a yeast consortium HYC, which is halotolerant and was recently isolated from wood-feeding termites. The consortium HYC was mainly comprised of Sterigmatomyces halophilus SSA-1575 and Meyerozyma guilliermondii SSA-1547. The developed consortium demonstrated a decolourization efficiency of 96.1% when exposed to a concentration of 50 mg/l of Reactive Black 5 (RB5). The HYC consortium significantly decolorized RB5 up to concentrations of 400 mg/l and in the presence of NaCl up to 50 g/l. The effects of physicochemical factors and the degradation pathway were systematically investigated. The optimal pH, salinity, temperature, and initial dye concentration were 7.0, 3%, 35 °C and 50 mg/l, respectively. The co-carbon source was found to be essential, and the addition of glucose resulted in a 93% decolorization of 50 mg/l RB5. The enzymatic activity of various oxido-reductases was assessed, revealing that NADH-DCIP reductase and azo reductase exhibited greater activity in comparison to other enzymes. UV-Visible (UV–vis) spectrophotometry, Fourier-transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC), and gas chromatography–mass spectrometry (GC-MS) were utilized to identify the metabolites generated during the degradation of RB5. Subsequently, a metabolic pathway was proposed. The confirmation of degradation was established through alterations in the functional groups and modifications in molecular weight. The findings indicate that this halotolerant yeast consortium exhibits promising potential of degrading dye compounds. The results of this study offer significant theoretical basis and crucial perspectives for the implementation of halotolerant yeast consortia in the bioremediation of textile and hypersaline wastewater. This approach is particularly noteworthy as it does not produce aromatic amines.

Eco-friendly oxidation of a reactive textile dye by CaO2: effects of specific independent parameters

ABSTRACT Textile wastewater containing dyes poses significant risks to the environment. Advanced oxidation processes (AOPs) effectively eliminate dyes by converting them into harmless substances. However, AOPs have drawbacks such as sludge formation, metal toxicity, and high cost. As an alternative to AOPs, calcium peroxide (CaO2) offers an eco-friendly and potent oxidant for dye removal. Unlike certain AOPs that generate sludge, CaO2 can be directly employed without resulting in sludge formation. This study examines the use of CaO2 for oxidizing Reactive Black 5 (RB5) in textile wastewater without any activator. Various independent factors—pH, CaO2 dosage, temperature, and certain anions—were investigated for their influence on the oxidation process. The effects of these factors on dye oxidation were analyzed using the Multiple Linear Regression Method (MLR). CaO2 dosage was determined to be the most influential parameter for RB5 oxidation, while the optimal pH for oxidation with CaO2 was found to be 10. The study determined that 0.5 g of CaO2 achieved approximately 99% efficiency in oxidizing 100 mg/L of RB5. Additionally, the study revealed that the oxidation process is endothermic, with an activation energy (Ea) and standard enthalpy (ΔH°) for RB5 oxidation by CaO2 determined as 31.135 kJ mol−1 and 110.4 kJ mol−1, respectively. The presence of anions decreased RB5 oxidation, with decreasing effectiveness observed in the order of PO4 3−, SO4 2−, HCO3 −, Cl−, CO3 2−, and NO3 −. Overall, this research highlights CaO2 as an effective, easy-to-use, eco-friendly, and cost-efficient method for removing RB5 from textile wastewater.

Upcycling polyvinyl chloride waste into highly efficient amine-functionalized nanofiber membrane adsorbent through the dissolution-modification-reforming process

Polyvinyl chloride (PVC) waste recycling is a challenging task and there is a great lack of convenient, feasible, and effective methods. In this work, a dissolution-modification-reforming process was proposed to upcycle PVC into highly efficient adsorbents (polyethylenimine-crosslinked PVC nanofiber membranes (PEI/PVC NFMs)). The effect of PEI to PVC mass ratio on the preparation of PEI/PVC NFMs was estimated. The adsorption performance of azo dyes on PEI/PVC NFMs was evaluated using Reactive Black 5 (RB5). The acid/alkali resistance of PEI/PVC NFM and its adsorption potential for various ionic pollutants were also investigated. Here are the results: The PEI/PVC NFMs exhibited high RB5 uptake within pH 2 to 8. The amine groups content in PEI/PVC NFM increased with increasing of PEI to PVC mass ratio, resulting in faster adsorption rates and higher adsorption capacity. With the mass ratio of PEI to PVC increased from 0.5:1.0 to 2.0:1.0, the adsorption equilibrium time reduced from 480 to 120 min, while the maximum RB5 uptake increased from 314.5 to 1036.7 mg/g. The adsorption isotherms and thermodynamic analysis revealed that physisorption dominated the adsorption process. The PEI/PVC NFM also exhibited good adsorption potential for various ionic pollutants, including per-/poly-fluoroalkyl substances (PFAS) and heavy metals (Pb2+, H2AsO4−, Co2+, and Ni2+). The 30-d acid/alkali resistance test confirmed that the PEI/PVC NFM has better stability at higher pH conditions. The PEI/PVC NFM exhibited good recyclability in azo dye wastewater treatment. In conclusion, this study demonstrates that the dissolution-modification-reforming process is a viable route for PVC waste upcycling. This pathway allows the conversion of PVC waste into highly efficient adsorbents for the elimination of ionic pollutants from water.

Sustainable and economical dolomite-modified biochar for efficient removal of anionic dyes

Dyes induce acute to chronic illnesses in humans and aquatic animals. This study tested dolomite-modified rice husk biochar (DRHB) to eliminate anionic reactive dyes Remazol Brilliant Blue (RBB) and Reactive Black 5 (RB-5) from simulated wastewater solutions. DRHB was produced by pretreating rice husk biomass with the natural mineral dolomite (CaMg(CO3)2) solution following pyrolysis step at 700 °C for 4 h at 8 °C min−1. Pristine rice husk biochar (PRHB) was made by pyrolyzing rice husk for 4 h at 700 °C. The DRHB and PRHB were characterized via different techniques including, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Scanning electron microscopy (SEM). Afterwards, DRHB was used to get rid of the dyes in the wastewater solutions, and the effects of dose, pH, and contact duration were studied. Both RBB and RB-5 exhibited maximal adsorption capacities of 52.07 and 35.518 mg/g at 50 °C, respectively, and the findings matched well with the Langmuir model, demonstrating monolayer adsorption. For this system, the pseudo-second-order fit is optimal, pointing to chemisorption of both substances. The outcomes presented higher adsorption for RBB (95.63%) compared to RB-5 (85.20%) at 70 mg/L concentration, pH 6, 4 hr. contact time, and 0.3 mg of DRHB dosage. The primary mechanism to remove of both dyes was chemisorption via π-π bond and hydrogen bond. These findings provide insights to build an economical, and sustainable anionic dyes removal technique especially for the third world nations.

Degradation of Reactive Black 5 Dye (RB5) using Iron Electrode (Fe.S) Derived from Iron Sludge Steel Waste via Electrochemical Method

A study has been performed on the degradation of Reactive Black 5 (RB5) as pollutant using iron electrode (Fe.S) derived from iron sludge steel waste via electrochemical method. The Fe.S and titanium graphite electrodes were applied as anode and cathode respectively during the studied. The studied operating parameters were the effect of current density, initial pH, initial concentration, and the reusability of the Fe.S electrode. The experiment was carried out for 120 minutes of electrolysis time. From results revealed that Fe.S could be used three times with complete degradation of RB5 from initial concentration of 50 ppm. A complete RB5 colour removal can be achieved in any pH range (3,6, and 9). The current density at 4 mA/cm2 showed a faster RB5 degradation compared to at 2, 6,8, and 10 mA/cm2.

Application of Hydrogen-Based Denitrification: Simultaneous Removal of Nitrate and Reactive Black 5 Dye from Textile Wastewater Containing Organic Matter

In this study, a hydrogen-based denitrification (HD) reactor was used to investigate the simultaneous treatment of nitrogen and decolorization in textile wastewater contaminated with organic matter. The reactor operated in two phases: without and with organic matter. Despite the short hydraulic retention time, the HD system successfully removed all pollutants, including nitrate, nitrite, reactive black-5 dye and chemical oxygen demand. The unhindered treatment efficiency for nitrogen and decolorization in the presence of organic pollutants was observed. With the addition of organic matter, the nitrogen removal efficiency increased slightly from 85% to 90–100%, and the decolorization rate doubled from 25% to 50–60%. Organic matter played a crucial role in stimulating heterotrophic bacteria during biological denitrification and acted as a carbon source facilitating biological denitrification and azo bond cleavage during dye degradation. Despite the generation of toxic byproducts and changes in the dominant microbial community, the treatment efficiency remained stable and improved. This approach offers a promising solution for enhancing treatment efficiency in textile wastewater, providing a cost-effective and environmentally friendly option for developing countries to treat wastewater before discharge.

The Effect of Modifying Canadian Goldenrod (Solidago canadensis) Biomass with Ammonia and Epichlorohydrin on the Sorption Efficiency of Anionic Dyes from Water Solutions.

This study examined the effect of modifying Canadian goldenrod (Solidago canadensis) biomass on its sorption capacity of Reactive Black 5 (RB5) and Reactive Yellow 84 anionic dyes. The scope of the research included the characteristics of sorbents (FTIR, elementary analysis, pHPZC), the effect of pH on dye sorption efficiency, sorption kinetics, and the maximum sorption capacity (describing the data with Langmuir 1 and 2 and Freundlich models). FTIR analyses showed the appearance of amine functional groups in the materials modified with ammonia water, which is indicative of the sorbent amination process. The amination efficiency was higher in the case of materials pre-activated with epichlorohydrin, which was confirmed by elemental analysis and pHPZC values. The sorption efficiency of RB5 and RY84 on the tested sorbents was the highest in the pH range of 2-3. The sorption capacity of the goldenrod biomass pre-activated with epichlorohydrin and then aminated with ammonia water was 71.30 mg/g and 59.29 mg/g in the case of RB5 and RY84, respectively, and was higher by 2970% and 2510%, respectively, compared to the unmodified biomass. Amination of biomass pre-activated with epichlorohydrin can increase its sorption capacity, even by several dozen times.

The Use of Exoskeletons and Molts of Farmed Mealworm (Tenebrio molitor) for the Removal of Reactive Dyes from Aqueous Solutions

The study aim was to test the applicability of exoskeletons and molts from mealworm (Tenebrio molitor) cultures as sorbents for anionic dyes: Reactive Black 5 (RB5) and Reactive Yellow (RY84). Factors investigated included: characteristics of sorbents (FTIR, pHPZC), the influence of pH on sorption efficiency, sorption kinetics (pseudo-first, pseudo-second-order, intraparticle diffusion models), and determination of the maximum sorption capacity (Langmuir 1, Langmuir 2, Freundlich, and Dubinin–Radushkevich models). The sorption efficiency of anionic dyes on the tested sorbents was the highest at pH 2. The time needed to reach the sorption equilibrium for both dyes was 120–150 min. The sorption kinetics of the dyes were best described by the pseudo-second-order model. Maximum sorption capacity data showed the best fit to Langmuir 2 isotherm, suggesting that at least two types of sorption centers played an important role in dye sorption. Presumably, for both of the tested sorbents, the active sites in question were protonated amine (-NH3+), acetamide (NH2COCH3+), and hydroxyl groups (-OH2+) of chitin and protein. The maximum RB5 and RY84 sorption capacity of the tested sorbents was 78.70 mg/g and 60.49 mg/g, respectively, for mealworm exoskeletons, as well as 55.72 mg/g and 44.25 mg/g, respectively, for mealworm molts.

Composite Activated Carbon Modified with AlCl3 for the Effective Removal of Reactive Black 5 Dye from Wastewaters

Many industries use huge amounts of synthetic dyes which may release into the wastewater in dyeing processes causing serious damage to aquatic life as they are recalcitrant, nonbiodegradable, stable to oxidizing agents, and toxic. Adsorption on activated carbon has been found to be a very efficient treatment method. In this work, a new adsorbent material composed of activated carbon and aluminum chloride (AC-Al) was prepared for the removal of a commercial anionic and anthraquinonic reactive dye, i.e., Reactive Black 5 (RB5) under various experimental conditions. Several parameters, such as the adsorbent’s dosage, initial RB5 concentration, pH, and contact time, were studied in order to determine the feasibility of AC-Al. According to the results, it was found that there was an increase in RB5 removal as the adsorbent’s dosage increased, especially, in pH 2 ± 0.1, where the removal rate increased, and reaching 100% by 1.0 g/L of AC-Al. Freundlich isotherm and pseudo-second-order kinetic models adequately fit the experimental data, indicating that favorable and heterogeneous adsorption occurred, closer to chemisorption. According to thermodynamics, it was found that the adsorption procedure was endothermic in nature (∆H0 = 62.621 kJ/mol) and spontaneous (∆G0 < 0), and according to the positive value of ∆S0 0.0293 (kJ/mol∙K), there is an increase in random interaction between solid and liquid interfaces. Finally, the AC-Al adsorbent was successfully regenerated and reused for four cycles.

Evaluation of the decolorization potential of azo dyes by aerobic granular sludge

This study assessed the azo dye decolorization potential by aerobic granular sludge (AGS), particularly investigating the effects of different electron donor substrates, redox mediators, dye structures, and alternative electron acceptors. Additionally, the stability and performance of an AGS reactor were evaluated during the treatment of a synthetic azo dye-containing effluent in the absence and presence of a redox mediator. Propionate and anthraquinone-2-sulfonate (AQS) were the best substrate (k1 1.1–1.9-fold higher) and redox mediator (k1 1.4-fold higher), respectively, for Reactive Black 5 (RB5) decolorization. AQS (50 μM) had a greater impact on Reactive Orange 16 (k1 = 15.60 h−1) than on Reactive Red 120 (k1 = 0.48 h−1) and RB5 (k1 = 7.92 h−1). Nitrate and sulfate (100 and 200 mg·L−1) inhibited dye reduction (decreasing k1 from 5.52 to 0.72 and 2.40 h−1, respectively), possibly because they compete with the dye for the electrons in the environment. However, AQS minimized their impact on this process (except for nitrate at 200 mg·L−1). In the reactor, RB5 and AQS did not alter the physical characteristics of AGS and its ability to remove organic matter and nutrients. Finally, the effect of AQS on decolorization was not so intense, increasing only ∼15%.

Nanostructured Mn–Ni Powders Produced by High-Energy Ball-Milling for Water Decontamination from RB5 Dye

In this study, the degradation efficiency of Mn-20at%Ni and Mn-30at%Ni particle powders made by melt-spinning and high-energy ball-milling techniques is investigated in relation to the degradation of the azo dye Reactive Black 5. SEM, EDS, and XRD were used to analyze the powders’ morphology, surface elemental composition, and phase structure. An ultraviolet-visible absorption spectrophotometer was used to measure the ball-milled powder’s capacity to degrade, and the collected powders were examined using the FTIR spectroscopy method to identify the substituents in the extract. The impact of MnNi alloy on the azo dye Reactive Black 5′s degradation and its effectiveness as a decolorizing agent were examined as functions of different parameters such as chemical composition, specific surface, and temperature. In comparison to the Mn-30at%Ni alloy, the powdered Mn-20at%Ni particles show better degrading efficiency and a faster rate of reaction. This remarkable efficiency is explained by the configuration of the valence electrons, which promotes more responding sites in the d-band when the Ni content is reduced. Therefore, increased electron transport and a hastened decolorization process are achieved by reducing the Ni concentration of RB5 solution with Mn80 particle powder. Additionally, this difference in their decolorization efficiency is explained by the fact that Mn-20at%Ni has the highest specific surface area of 0.45 m2 g−1. As the main result, the functional uses of nanostructured metallic powder particles as organic pollution decolorizers in the textile industry are greatly expanded by our study.

Biosorption of Reactive Black 5 Dye from Aqueous Solutions by Spirulina and Perna canaliculus Biocomposite in Batch and Fixed-Bed Systems

Biosorption of Reactive Black 5 Dye from Aqueous Solutions by Spirulina and Perna canaliculus Biocomposite in Batch and Fixed-Bed Systems

CuCr NLDH-Graphene oxide blended polyvinyl chloride ultrafiltration membrane with improved permeability and antifouling behavior

The modification of filtration membranes with the aim of improving their permeability, stability, and antifouling properties is essential, which can be achieved by the development of novel materials or methods. In this context, the utilization of new nanomaterials is one of the considered approaches for polymeric membrane modification. In this study, the applicability of CuCr NLDH-GO incorporation with the objective of improving hydrophilicity, permeability, and antifouling properties of polyvinyl chloride (PVC) ultrafiltration membrane is reported. After synthesis of CuCr NLDH-GO by co-precipitation method, its effect on the performance of PVC membrane was investigated by incorporation of different concentrations (0–2 wt%) of CuCr NLDH-GO. The significant decline of the water contact angle from 76.4° to 63.5° indicated the hydrophilicity improvement. This hydrophilic property was effective for almost twofold enhancement of the pure water permeability from 23.7 L/m2.h.bar of the bare membrane to 53.7 L/m2.h.bar of the membrane containing 1 wt% CuCr NLDH-GO. Moreover, the modified membranes indicated improved antifouling performance by increasing flux recovery ratio values from 54.3 % to 65 %. The performance of membranes in rejection of two different dyes, including reactive yellow 160 (RY160) and reactive black 5 (RB5) showed that the incorporation of CuCr NLDH-GO is not only effective for antifouling behavior but also suitable for improving dye rejection of membranes.

Reactive Black-5, Congo Red and Methyl Orange: Chemical Degradation of Azo-Dyes by Agrobacterium

The commercial processing of various biomaterials extensively uses azo dyes (including reactive, direct, acidic, and basic dyes). These industrial applications produce wastewater containing a large volume of solubilized azo dye and hydrolyzed by-products. The treatment of such wastewater is primarily carried out by chemical and, to an extent, physical methods, which lack selectivity and efficiency. Notably, the chemical methods employ free radicals and oxidizing agents that further increase the chemical waste and produce non-biodegradable side-products. Therefore, there is an increasing trend of using microbial-assisted methods. The current study identified a specific Agrobacterium strain (JAS1) that degraded the three structurally distinct azo dyes (Reactive Black 5, Methyl Orange, Congo Red). JAS1 can tolerate high concentrations and be used to perform the in-solution degradation of azo dyes, respectively: Methyl Orange (5.5 g/L and 5.0 g/L), Congo Red (0.50 g/L and 0.40 g/L), and Reactive Black 5 (0.45 g/L and 0.40 g/L). Our study elucidated the molecular mechanisms (primarily enzymatic degradation and adsorption) responsible for the JAS-1-assisted decoloration of azo dyes. The JAS-1-assisted degraded products from these azo dyes were found biodegradable as the germination and seedling growth of wheat seeds were observed. To enhance the scope of the study, JAS1-assisted decolorization was studied for cellulosic materials, indicating a potential application in de-inking and de-dyeing process in recycling industries.

Enhanced degradation of azo dye using mixed cultures of white-rot fungi in a modified rotating packed disc bioreactor and reuse of treated water

Reactive azo dyes are toxic and carcinogenic. In this study, mixed cultures of white-rot fungi (WRF) are used to treat synthetic reactive black 5 (RB-5) wastewater in a modified rotating packed disc bioreactor (RPDB). The continuous degradation studies were carried out for 25 days under the influence of the recycle stream in which 3665 L of synthetic effluent was treated. The dye wastewater was completely decolorized with more than 93 % chemical oxygen demand (COD) reduction using the mixed fungal culture. During the continuous operation, the COD of influent reduced more than 85 % for successive 25 days of continuous operation at hydraulic retention time of 10.8 h. The dry biomass loading was about 0.14 g/g GAC at the end of the continuous process. The rate of COD removal followed first order kinetics with a rate constant of 0.026 per hour. The treated water was reused to produce melanin from microbial culture.

Exploration of Reactive Black 5 Dye Desorption from Composite Hydrogel Beads—Adsorbent Reusability, Kinetic and Equilibrium Isotherms

A low-cost adsorbent was prepared by using cherry stones powder and chitosan and used to retain Reactive Black 5 dye from aqueous solution. Then, the spent material was submitted to a regeneration process. Five different eluents (water, sodium hydroxide, hydrochloric acid, sodium chloride and ethanol) were tested. Among them, sodium hydroxide was selected for an advanced investigation. Values of three working conditions, namely the eluent volume, its concentration and the desorption temperature, were optimized by Response Surface Methodology-Box-Behnken Design. In the established settings (NaOH volume: 30 mL, NaOH concentration: 1.5 M, working temperature: 40 °C), three successive cycles of adsorption/desorption were conducted. The analysis performed by Scanning Electron Microscopy and by Fourier Transform Infrared Spectroscopy revealed the evolution of the adsorbent throughout the dye elution from the material. Pseudo-second-order kinetic model and Freundlich equilibrium isotherm were able to accurately describe the desorption process. Based on the acquired results, our outcomes sustain the suitability of the synthesized material as dye adsorbent and the possibility of efficaciously recycling and reusing it.

Converting synthetic azo dye and real textile wastewater into clean energy by using synthesized CuO/C as photocathode in dual-photoelectrode photocatalytic fuel cell.

Cathode in photocatalytic fuel cell (PFC) plays a crucial role in degradation of organic contaminants. In this study, synthesized copper oxide (CuO) was loaded on carbon plate and used as photocathode in PFC for degradation of synthetic azo dye Reactive Black 5 (RB5) and real textile wastewater. Morphology and structural phase of the synthesized CuO were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Several operating parameters had been investigated such as light irradiation, initial dye concentration, and pH of azo dye solution within 6h of irradiation time. The lowest initial concentration of RB5 (10mg L-1) achieved 100% color removal compared to the highest initial concentration (40mg L-1) which only achieved 77.1% color removal within 6h of irradiation time. The influence of external resistance was significant in electricity generation but trivial in dye degradation efficiency. The external resistance of 6000 Ω yielded highest maximum power density, with Pmax of 0.2631μWcm-2, followed by 1000 Ω (0.2196μWcm-2) and 8000 Ω (0.1587μWcm-2), respectively. The real textile wastewater with dilution ratio (DR) 1:6 yielded the highest energy conversion efficiency, η (3.62%), followed by DR 1:4 (3.19%) and DR 1:2 (1.96%), respectively.

Exploring the self-cleaning and antimicrobial efficiency of the magnesium oxychloride cement composites

Composites of magnesium oxychloride cement (MOC) functionalized with TiO2 nanoparticles are proposed here as an alternative technology to maintain clean building surfaces from airborne pollutants and microorganisms. The MOC composites were characterized by different techniques such as XRD, FTIR, SEM, EDS, UV–Vis, compressive strength, and nanoindentation tests. According to the results, phase 3 (3 Mg(OH)2.MgCl2.8H2O) with needle-like morphology was the primary crystallized hydration product for the MOC composites. Also, the samples exhibited good mechanical properties and good light absorption, allowing them to activate under solar light irradiation. The self-cleaning efficiency of the MOC composites was evaluated by measuring the removal of three types of pollutants: methylene blue (MB), rhodamine B (RhB), and reactive black 5 (RB5), under two scenarios: natural sunlight and accelerated weathering conditions. The self-cleaning tests revealed outstanding efficiencies of the composites to remove MB (82%), RhB (88%), and RB5 (91%) under solar light and accelerated weathering tests. On the other hand, the antimicrobial activity was evaluated against E. coli (gram-negative) and S. aureus (gram-positive) under irradiation. The zone of inhibition (ZOI) showed diameters higher than 21 mm to E. coli for samples with 5% of TiO2 or superior, revealing a high microbial inhibition of the gram-negative bacteria. Also, the structural and morphological stability of the MOC composites was confirmed after several cycles for the accelerating weathering tests, demonstrating their potential to be used outdoors to reduce environmental pollution.

Isolation and Characterisation of Electrogenic Bacteria from Mud Samples.

To develop efficient microbial fuel cell systems for green energy production using different waste products, establishing characterised bacterial consortia is necessary. In this study, bacteria with electrogenic potentials were isolated from mud samples and examined to determine biofilm-formation capacities and macromolecule degradation. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identifications have revealed that isolates represented 18 known and 4 unknown genuses. They all had the capacities to reduce the Reactive Black 5 stain in the agar medium, and 48 of them were positive in the wolfram nanorod reduction assay. The isolates formed biofilm to different extents on the surfaces of both adhesive and non-adhesive 96-well polystyrene plates and glass. Scanning electron microscopy images revealed the different adhesion potentials of isolates to the surface of carbon tissue fibres. Eight of them (15%) were able to form massive amounts of biofilm in three days at 23 °C. A total of 70% of the isolates produced proteases, while lipase and amylase production was lower, at 38% and 27% respectively. All of the macromolecule-degrading enzymes were produced by 11 isolates, and two isolates of them had the capacity to form a strong biofilm on the carbon tissue one of the most used anodic materials in MFC systems. This study discusses the potential of the isolates for future MFC development applications.

Synthesis of copper‐oxide nanoparticles from Euphorbia antiquorum extract and evaluation of its dye degradation capacity

AbstractDye discharge from industrial textile effluent is hazardous to the environment. Hence, the removal of dye has become important as it affects both human and aquatic life, even if it is present in minimal amounts. In comparison to the physio‐chemical technique, photocatalytic degradation of the dye using nanoparticles that are generated biologically provides a feasible method for the breakdown of environmental pollutants. Unlike other metal oxides, Copper oxide nanoparticles (CuONPs) have attracted the attention of many researchers due to their potential to act as photocatalyst and also because of their enormous surface area. Euphorbia antiquorum (triangular spurge) is a common thorny succulent found all over peninsular India, primarily in dry areas. The aqueous extract of the selected plant was employed to synthesis CuONPs, which were then analyzed using SEM‐EDX, FTIR, XPS, and XRD. The present study describes how CuONPs derived from the extract of E. antiquorum degrade major commercial dyes such as Congo Red (CR), Coomassie Brilliant Blue (CBB R‐250 dye, and Reactive Black (RB). The photocatalytic degradation efficiency of synthesized CuONPs has been demonstrated for a wide range of dyes used in the textile industry. Dye degradation of RB using synthesized CuONPs showed 93% efficiency.