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New azo Schiff base disperse dyes based on a chromene moiety were synthesized by reacting (2-amino-7-hydroxy-4-(4-methoxyphenyl)-4 H-chromene-3 carbonitrile) and(2-amino-4-(3,4-dimethoxyphenyl)-7-hydroxy-4 H-chromene-3-carbonitrile), with vanillin and ninhydrin, producing new chromene Schiff base derivatives, which in turn were coupled with 2-chloro-4-nitroaniline diazonium salt to give new 4 azo disperse dyes (1–4). The structures of the prepared dyes were confirmed using elemental analysis, 1HNMR spectroscopy, mass spectrometry, and IR. The synthesized dyes were applied to polyester and nylon fabrics using different dyeing techniques: high temperature- high pressure, and ultrasonic dyeing methods. The highest K/S values for all investigated dyes were achieved usinga high temperature-high pressure dyeing technique. Also, the color reflectance of all synthesized dyes with different dyeing shades (1%, 2%, and 3%) was obtained. The fastness properties of the dyed samples using the investigated dyes showed good color fastness toward light, washing, rubbing, and perspiration fastness. The presence of a chromene moiety and Schiff base in the investigated dyes promotes a higher antimicrobial activity on nylon and polyester fabrics against all tested bacteria (E. coli gram-negative and Staphylococcus aureus gram-positive) and two fungi, Aspergillus Niger and Candida albicans. [ABSTRACT FROM AUTHOR]

Synthetic dyes such as azo dyes are significant pollutants in the wastewater released from various textile industries. The low biodegradability and production from synthetic sources with high shelf life make azo dyes a challenging material for degradation. This study used chemically mutated Aspergillus terrus in the laccase production under solid-state fermentation using sugarcane bagasse. Initially, the wild-type strain produced a laccase activity of 4.12 U/mL. Later, the alkaline pretreatment of sugarcane bagasse showed a significant increase in laccase activity by 38.9%. Further, random mutagenesis treatment with 100 mM EMS generated a hyper laccase-producing strain with a 2.3-fold increment in laccase activity compared to the wild-type strain. The enzyme displayed optimal activity at pH 6.5 and 35 °C. The metal ions such as Fe3+ (29.4 U/mL), Fe2+ (20.8 U/mL) and Cu2+ (18.05 U/mL) showed positive effects on laccase activity. The crude laccase was used to bioremediate Congo red, a prominent azo dye used in textile and pharmaceutical industries. The preliminary studies with a crude enzyme displayed 68.86% dye decolourization after 24 h of incubation. Additionally, with Taguchi orthogonal array optimization experiments, the maximal dye decolorization of 78.24% was achieved by maintaining crude enzyme concentration (20 U), dye concentration (25 mg/L) and pH 4.5. [ABSTRACT FROM AUTHOR]

Transition metal-based mixed metal oxides (MMOs) are nexus nanomaterials that garner significant interest from scientists because of their unique magnetic, electronic, optical and catalytic properties that can easily be tailored by varying their composition and structure. Although MMOs hold significant potential in multifunctional applications, but they are plagued by certain challenges such as identifying the appropriate method for synthesis, complications in controlling the surface area and the oxidation states of the constituent transition metals, while also ensuring the homogenous distribution of the constituent metal ions. Therefore, the present work aims to study the formation of homogenous and porous zinc-copper-nickel mixed metal oxide (ZnCuNi-MMO) by performing calcination of ZnCuNi-LDH at 350 °C. The obtained ZnCuNi-MMO was characterized using PXRD, SEM–EDX and BET techniques. Thereafter, ZnCuNi-MMO was applied as a heterogeneous catalyst for the hydrogenation of p-nitroaniline (p-NA) and catalytic reduction of methyl orange (MO) dye. The pollutant degradation characteristics were assessed using time-dependent UV–Visible absorption spectroscopy showing advanced efficient behavior of ZnCuNi-MMO towards the hydrogenation of p-NA (96.98%) and reduction of MO (95.58%). The catalyst exhibited fast reaction rates (0.402 min−1 for hydrogenation of p-NA and 0.471 min−1 for catalytic reduction of MO) and kinetics analysis of the experimental data was found to be coherent with the pseudo-first order model, thereby implying that the catalysis proceeded through the Langmuir–Hinshelwood mechanism. Thus the obtained experimental results highlight the utility and viability of synthesized MMO as an efficacious and sustainable catalytic material. [ABSTRACT FROM AUTHOR]

Dyes are the coloured substances that are applied on different substrates such as textiles, leather and paper products, etc. Azo dyes release from the industries are toxic and recalcitrant wastewater pollutants, therefore it is necessary to degrade these pollutants from water. In this study, the palladium (0) nanoparticles (PdNPs) were generated through the biological process and exhibited for the catalytic degradation of azo dye. The palladium nanoparticles (PdNPs) were synthesized by using the cell-free approach i.e. extract of fungal strain Rhizopus sp. (SG-01), which significantly degrade the azo dye (methyl orange). The amount of catalyst was optimized by varying the concentration of PdNPs (1 mg/mL to 4 mg/mL) for 10 mL of 50 ppm methyl orange (MO) dye separately. The time dependent study demonstrates the biogenic PdNPs could effectively degrade the methyl orange dye up to 98.7% with minimum concentration (3 mg/mL) of PdNPs within 24 h of reaction. The long-term stability and effective catalytic potential up to five repeated cycles of biogenic PdNPs have good significance for acceleration the degradation of azo dyes. Thus, the use of biogenic palladium nanoparticles for dye degradation as outlined in the present study can provide an alternative and economical method for the synthesis of PdNPs as well as degradation of azo dyes present in wastewater and is helpful to efficiently remediate textile effluent. [ABSTRACT FROM AUTHOR]

A global water crisis is emerging due to increasing levels of contaminated water and decreasing clean water supply on Earth. This study aims to address the removal of azo dye from wastewater to enable its reuse. Recently, utilizing microorganisms has been proven to be a practical choice for the remediation of azo dyes in wastewater. Hence, in this study, we employed a preformed biofilm of Pseudomonas aeruginosa on a solid support (called substrate) to degrade azo dyes. This process offers several advantages, such as stability, substrate portability, more biofilm production in less time, and efficient utilization of enzymes for remediation. From 50 ppm of initial Congo Red concentration, 75.74% decolorization was achieved within ten h using a preformed biofilm on a coverslip. A maximum of 52.27% decolorization was achieved using biofilm during its formation after 72 h of incubation. The Fourier-transform infrared (FTIR) spectroscopic analysis of Congo Red dye before and after remediation revealed a significant change in peak intensity, indicating dye degradation. Phytotoxicity studies performed by seed germination with Vigna radiata revealed that, after 5–7 days, almost 40% more seeds with longer root and shoot lengths were germinated in the presence of treated dye compared to the untreated one. This data indicated that the harmful Congo Red was successfully degraded to a non-toxic product by Pseudomonas aeruginosa biofilm grown on a glass substrate. [ABSTRACT FROM AUTHOR]

The biodegradation and detoxification potential of two azo disperse dyes and one anthraquinone disperse dye (commonly found in the wastewater effluent of a local textile industry) was investigated by using a consortium of six indigenously isolated bacteria from the wastewater stream in this study. It was found that consortium of bacteria can decolorize disperse red 167.1 dye at concentrations of 50, 150, and 250 mg/L more effectively and the other two dyes, disperse red 54 and disperse blue 60 dyes were decolorized more efficiently by individual bacteria. Bacterial strains namely Bacillus cereus AU50, Bacillus sphaericus, Paenibacillus pocheonensis sp. C-2, Paenochrobactrum glaciei, Bacillus subtilis and Brevibacillus panacihumi were isolated from a local textile industry wastewater stream (effluent) located in Ludhiana, Punjab, India and were used in this study to treat textile industry wastewater containing toxic dyes. The consortium (comprising of these six bacterial isolates) resulted in the maximum rate of decolorization (82.76 ± 0.255%) for disperse red 167.1 dye at three different concentrations within 24 h, with the increase in enzymatic activities whereas Bacillus cereus exhibited maximum rate of decolorization (84.17 ± 0.16%) for disperse red 54 and (76.29 ± 0.51%) for disperse blue 60 in 24 h.In addition, degradation pathways of selected dyes were investigated based on the intermediates identified by GC–MS and followed by phytotoxicity assay. Results of this study show the potential of naturally occurring bacteria in the treatment of wastewater by biodegrading textile dyes in the wastewater streams. The findings of this research will result in developing economically viable bio-filters where bacterial strains can be used to biodegrade textile industry pollutants before this wastewater enters local rivers and streams, and help improve water quality of rivers and aquatic ecology. [ABSTRACT FROM AUTHOR]

Tartrazine, an azo dye prevalent in pharmaceuticals and food items, was investigated for its impact on fetal development, specifically examining visceral and skeletal abnormalities in rat offspring exposed to daily oral doses throughout pregnancy. Fourteen pregnant rats were randomly assigned to control and tartrazine groups (seven animals each), with tartrazine administered via oral gavage at 7.5 mg/kg throughout gestation. Offspring were categorized by gender for histopathological and genetic analysis of visceral structures. Bone quality and fracture resistance assessments involved micro‐CT, Raman spectroscopy, and biomechanical testing. Results highlighted distinct internal organ tissue differences in the tartrazine group, notably increased hemorrhagic and inflammatory cell infiltration, degeneration, and vacuolization compared to controls. Gender‐specific alterations in mRNA levels of IL‐6, IL‐1β, TNF‐α, and TRPM2 genes (p < .001) were also noted. Moreover, tartrazine‐exposed groups exhibited reduced trabecular thickness, bone volume, and significant alterations in bone matrix composition and quality alongside significant decreases in fracture resistance (p < 0.05). This study concludes that intrauterine exposure to tartrazine can result in adverse impacts on organ and bone development in rat offspring. [ABSTRACT FROM AUTHOR]

AbstractThe present study evaluated and characterized the performance in the biosorption of the dye azo Reactive Red 2 (RR2) on thermally sterilized biomass of the fungus Trichoderma reesei. An FTIR analysis of unloaded and loaded biomass with RR2 confirmed the interactions between dye molecules and functional groups on the fungal biomass surface. The decrease in the initial pH of 9 to 3 with an increase in the temperature of 20 to 40 °C improved the biosorption, reaching for RR2 a higher removal efficiency of 76.88% at pH 3 and 40 °C. A pseudo-second-order model explained the biosorption kinetics of RR2 (R2≥0.9869), and the intraparticle diffusion model showed that the biosorption process was initially controlled by diffusion rate and later by biomass surface saturation with the dye molecules. The Langmuir isotherm explained the biosorption equilibrium well (R2 ≥ 0.9241), achieving the maximum biomass biosorption capacity (qmax) value at 61.72 mg g−1. The dimensionless separation factor values (0.0632 ≤ RL ≤ 0.0973) and the thermodynamic evaluation of the process (ΔG° ≤ −24.09 kJ mol−1, ΔH° ≥ 12.39 kJ mol−1, ΔS° ≥ 0.1265 kJ mol−1 K−1) demonstrate that the biosorption was favorable, reversible, spontaneous, and endothermic. The findings in the present study allow it to consider the biomass of Trichoderma reesei thermally sterilized as a biosorbent biomaterial that can be used for bioprocess design in removing the azo reactive dyes from textile wastewater. [ABSTRACT FROM AUTHOR]

This review explores advancements, challenges, and considerations in photocatalytic dye degradation for sustainable wastewater treatment. It highlights smart photocatalyst design, visible‐light‐responsive materials, and co‐catalyst engineering, which enhance system efficacy. Despite environmental concerns, the eco‐friendly aspects of photocatalysis offer a promising alternative to traditional methods. Future perspectives emphasize nanotechnology's role in developing effective photocatalysts and integrating visible‐light and solar‐driven systems to meet sustainability goals. Efforts in co‐catalyst engineering and reactor design aim to optimize processes, addressing kinetic and scalability challenges, while economic research focuses on reducing costs to improve competitiveness. [ABSTRACT FROM AUTHOR]

We synthesized some novel isoxazole azo derivatives using conventional methods and studied their linear, non‐linear optical properties and antioxidant activity. UV‐Vis spectroscopy revealed absorption bands ranging from 310–470 nm for the obtained compounds. Compounds 3 c and 3 b, for example, showed a large redshift and solvatochromic behavior. NLO analysis results show that compounds exhibit a greater NLO response than the magnitude of urea done by the DFT method. The electrochemical properties of compounds are studied using cyclic voltammetry and results are used for calculation of HOMO and LUMO experimentally. The antioxidant activity of the synthesized azo dyes displayed that 3 c has excellent antioxidant activity with the highest percentage (71.54605 %) of radical inhibition as compared to reference standard Vit‐C. Molecular docking analysis shows that compounds have a strong binding affinity in the range of −7.0 to −4.6 kcal/mol compared to Vit‐C, which has a binding affinity of −3.6 kcal/mol. The sun protection factor performance was determined by UV‐Vis spectroscopy, and results show that compounds are most effective, exhibit a remarkable SPF value, and offer superior sun protection by absorbing UV rays. [ABSTRACT FROM AUTHOR]

The evaluation of the adsorption capacity of amine‐functionalized silica coated iron oxide magnetic particles (Fe3O4/SiO2‐NH2) as a highly recyclable adsorbent for Congo Red (CR) and Eriochrome Black T (EBT) azo‐dyes from water is reported. The Fe3O4/SiO2‐NH2 were prepared by a simple co‐precipitation method of iron oxide (Fe3O4) nanoparticles followed by silica coating on oleic acid coated Fe3O4. A series of investigation was performed to assess the various experimental parameters like contact time (0–360 min), pH (3–10), stirring speed (0–500 rpm), adsorbent dosages (0.02–0.12 g) and initial concentrations (0.02–0.15 mg mL−1) of dyes. According to the Langmuir isotherm, the maximum adsorption capacities of CR and EBT on Fe3O4/SiO2‐NH2 particles were found to be 211.86 mg g−1 and 81.98 mg g−1, respectively. In comparison, the pseudo‐second order model provided adsorption capacities of 200.40 mg g−1 for CR and 80.91 mg g−1 for EBT. Additionally, the maximum adsorption amounts of CR and EBT on Fe3O4/SiO2‐NH2 particles were 179.37 mg g−1 and 75.43 mg g−1, achieved within 300 min and 180 min at pH 3, respectively. The dye‐loaded particles were recoverable for CR and EBT removal by simple regeneration with 0.1 molL−1 NaOH solution to use the particles until more than five cycles. [ABSTRACT FROM AUTHOR]

The aim of this study is to discover the potential use of nutraceutical industrial cumin seed spent (NICUS) as an economical biosorbent for eliminating acid blue 113 (AB113), an azo dye, from water. The study investigates the influence of pH, adsorbent dosage, temperature, particle size, and initial dye concentration on the adsorption of AB113. Various isotherm models and kinetic models were studied. At equilibrium situations, the maximum trial adsorption volume (qe) was found to be 96 mg g−1. The main objective was to determine the suitability of the pseudo-second-order model for describing the kinetics of adsorption. Thermodynamic parameters ΔG0ΔH0ΔS0 revealed that the adsorption process was endothermic and non-spontaneous. The lower value of ΔH0 suggests a physical adsorption process. Analysis using FTIR and SEM spectra confirmed that the NICUS surface effectively adsorbed AB113. NICUS emerges as a promising adsorbent for the efficient deduction of AB113 from aqueous solutions. [ABSTRACT FROM AUTHOR]

Textile wastewater containing dyes poses significant environmental hazards. Advanced oxidative processes, especially the heterogeneous photo-Fenton process, are effective in degrading a wide range of contaminants due to high conversion rates and ease of catalyst recovery. This study evaluates the heterogeneous photodegradation of the azo dyes Acid Red 18 (AR18), Acid Red 66 (AR66), and Orange 2 (OR2) using magnetite as a catalyst. The magnetic catalyst was synthesized via a hydrothermal process at 150 °C. Experiments were conducted at room temperature, investigating the effect of catalyst dosage, pH, and initial concentrations of H2O2 and AR18 dye. Kinetic and thermodynamic studies were performed at 25, 40, and 60 °C for the three azo dyes (AR18, AR66, and OR2) and the effect of the dye structures on the degradation efficiency was investigated. At 25 °C for 0.33 mmolL−1 of dye at pH 3.0, using 1.4 gL−1 of the catalyst and 60 mgL−1 of H2O2 under UV radiation of 16.7 mWcm−2, the catalyst showed 62.3% degradation for AR18, 79.6% for AR66, and 83.8% for OR2 in 180 min of reaction. The oxidation of azo dyes under these conditions is spontaneous and endothermic. The pseudo-first-order kinetic constants indicated a strong temperature dependence with an order of reactivity of the type OR2 > AR66 > AR18, which is associated with the molecular size, steric hindrance, aromatic conjugation, electrostatic repulsion, and nature of the acid–base interactions on the catalytic surface. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride is a semiconducting material of a graphite-like 2D layered structure. It is well known for its photocatalytic properties, which can be exploited for solar-light-driven water splitting and degradation of organic pollutants. Here, we report its capabilities of catalyzing the reduction of the azo bond by hydrazine to two amines under visible light. This photocatalytic reaction provides a novel, appealing way to reduce azo dye wastes as pollutants other than degradation. With this method, the azo dye wastes can be photochemically converted to amines, which can be used as precursors for new azo dyes. [ABSTRACT FROM AUTHOR]

Heat management and color appearance are the key issues for the application of smart windows. Herein, a vibrant colored energy-saving polymer-dispersed liquid crystal (PDLC) film has been designed by combining dye-doping and the application of a heat shielding electrode. The LC droplet size could be varied by tuning the content of the dye. PDLC films featuring a low Disperse Orange 25 Azo dye concentration (0.06%) achieving an impressive contrast ratio of up to 101.5 with the transmittance reaching 79.17% at on state. Furthermore, indium tin oxide (ITO) and aluminum-doped zinc oxide (AZO) were chosen as the conductive layer materials, and the heat shielding properties of ITO and AZO/Ag/ITO (AAI) films were applied to PDLC devices and comparatively investigated. The AAI-based devices exhibited temperature reductions of 2 °C and 4 °C compared to the ITO-based devices at off and on states, respectively. This highlights the remarkable heat shielding performance and energy-saving capability of AAI-PDLC devices, as well as good flexibility and cycle stability. These AAI-based colored PDLC films exhibit substantial potential for smart window applications especially in buildings and automotive industry. [ABSTRACT FROM AUTHOR]

Dyes can be considered the main contaminants of textile effluents, which have a heterocyclic complicated structure. Disperse dyes are one of the most commonly used classes of dyes with an insoluble nature and low molecular weight. In this study, the elimination of disperse dyes from aqueous medium was investigated by Aspergillus niger fungi using in vivo and in vitro methods. According to the in vitro decolorization results, the fungi showed high biosorption capacity for three different disperse dyes. At an initial dye concentration of 330 mg/l , the adsorption capacity of A. niger measured 225.3 mg/g for Disperse Yellow 23, 127.4 mg/g for Disperse Blue 183, and 176.3 mg/g for Disperse Red 1. Complete dye removal was achieved at lower initial concentrations after a 6-h operation. The results showed that the biosorption process favored acidic conditions, and the adsorption capacity and rate were higher at pH 4.5. Moreover, the kinetics of the adsorption process for all dyes followed the pseudo–second-order kinetic model. An in vivo decolorization test was also performed, in which A. niger was inoculated in a dye-containing medium to investigate the possible biodegradation of the dye by fungi during its growth. The biodegradation process was studied by Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC) methods. The results obtained showed a maximum biodegradation of 49.77% for Disperse Red 1, whereas the decolorization for other dyes was mainly based on biosorption. Practical Applications: The industrial wastewater treatment plans in most dyeing houses consist of preliminary coagulation and flocculation tanks followed by biological wastewater treatment by activated sludge. According to the results of this study, A. niger could be applicable in both wastewater treatment steps in industrial plans. A. niger, as a nonharmful microorganism, could be used as a good adsorbent in the coagulation tanks, replacing the chemical coagulants. The adsorbed dye in A. niger's body mass could easily be separated because of its bulky structure. Because dye removal in this method is nearly complete, the effluent could be used in the same dyeing process without much refining process. Using A. niger in biological aerobic procedures could also be practicable according to the results. A. niger could grow in the aerobic condition of biological tanks and simultaneously degrade and adsorb dye molecules. On the other side, A. niger is commercially used for the production of citric acid, and some enzymes and the body mass produced by these industries could be considered for dye removal processes. The use of A. niger as a biosorbent or degradant for dyes still could be studied in several aspects. The study of the degradation mechanism of different dyes by precise tests like liquid chromatography (LC)-mass is an ongoing study by the current team. Also, using A. niger for real wastewater from dyeing houses and optimizing the dye removal parameters for industrial application is a future research perspective in this case. [ABSTRACT FROM AUTHOR]

Novel azo dye ligand [4‐([2,3‐dimethyl‐5‐oxo‐1‐phenyl‐2,5‐dihydro‐1H‐pyrazol‐4‐yl]diazenyl)‐3‐hydroxybenzaldehyde (HL)] and its Co(II), Ni(II), Ru(III), and Zr(IV) metal chelates, were produced and thoroughly described applying modern spectral and analytical approaches. The results showed that HL chelated in tridentate mode, leading to octahedral geometry toward the present metal ions where Co(II), Ni(II), and Zr(IV) complexes exhibit outer sphere hybridization, while the Ru(III) complex exhibits inner sphere hybridization. The calculated particle size values of the complexes reached 41.34, 46.41, 48.67, and 33.37 nm for Co(II), Ni(II), Ru(III), and Zr(IV) chelates, respectively applying the Debye–Scherrer equation on XRD patterns. When compared to its metal complexes, the ligand's antibacterial action against several bacteria demonstrates increased activity. Tests were conducted on A‐549 and PANC‐1 cells to evaluate the compounds' anticancer efficacy against the vinblastine standard. Co(II) nanosized complex exhibited cytotoxicity that was greater than that of the reference medication vinblastine sulfate against A‐549 cell line. It is promising to use the Co(II) complex to create novel anticancer medications. Quantum chemical calculations for ligand and its solid metal complexes were carried out utilizing the DFT of the DMOL3 module. Furthermore, the molecular docking studies were conducted on the A‐549 protein, associated with FGFR1, using the Schrödinger suite. The ligand and the Ru(III) complex exhibit the most potent inhibitory effects on the FGFR1 protein, a receptor tyrosine kinase integral to cellular growth and differentiation. [ABSTRACT FROM AUTHOR]

This work reports the results of coupling Moringa oleifera seed extract (MOSE) with electrocoagulation (EC) for the remediation of Direct Red 80 azo dye (DR80) from contaminated synthetic aqueous solution and real textile wastewater. The electrochemical treatment was carried out using a pair of aluminium electrodes in monopolar-parallel mode. EC runs determined using Box-Behnken design under the response surface methodology (RSM) for three parameters including current density, pH, and operation time. The EC optimal conditions were current density 0.9 mA/cm2, pH 3, and time 10 min. The maximum experimental DR80 dye removal of 89.37% was close to the model prediction (76.4%). The kinetic study of the EC system represented that the removal of dye obeyed the first-order kinetic model. To improve dye removal efficiency from treated wastewater under optimal conditions, 2.5 mL/L of MOSE was added and the efficiency enhanced to above 98%. SEM and microscopic images of the sludge produced showed that the flocs formed in the hybrid system were denser and thicker than the conventional EC. The economic study revealed that switching from the EC to hybrid process reduced energy and electrode consumption from 0.015 to 0.008 kWh/m3 and 0.016 to 0.014 kg/m3, respectively, for 98% DR80 dye removal. MOSE has a substantial effect on the EC performance. Therefore, the EC/MOSE coupling process is recommended for the treatment of coloured wastewater due to its high efficiency, short operation time, and electrode and energy consumption costs. [ABSTRACT FROM AUTHOR]

Azo dye degradation utilizing microorganisms has acquired significance over the last decades, owing to its beneficial properties such as rapid degradation, economic feasibility, and eco‐friendly. In this work, azo dyes (Methyl red and methylene blue) degradation efficacy using indigenous bacterial strains Pseudomonas sp. and Bacillus sp. as free and immobilized cells were investigated under in vitro batch decolorization setup was carried. Most importantly, the bacterial cells of both strains were immobilized with sodium alginate and the immobilized cells were evaluated for dye decolorization efficacy under laboratory conditions. An eco‐toxic assessment of the degraded products was done using in vitro phytotoxicity tests and in silico analyses. Among the free and immobilized cells, maximum decolorization efficacy was observed in the Pseudomonas sp. immobilized cells which exhibited 74.5% decolorization efficacy, and the maximum decolorization efficacy of free cells was 63% of was observed. Ecotoxicity of the dye‐degraded products was screened by determination of phytotoxicity. Seedlings emergence of groundnut seeds exposed to degraded dye products revealed phytotoxicity. Results indicated that degraded dye products of methyl red derived from Pseudomonas sp. showed 93.0% seedling emergence, and methylene blue‐degraded products Pseudomonas sp. degraded dye products supported 92.0% seedling emergence, respectively. Bacterial cells immobilized with biocompatible polymers can be effectively utilized in wastewater treatment without affecting the ecological components. The findings highlight the value of this work in contributing to the domain of sustainable and eco‐friendly wastewater treatment technology. [ABSTRACT FROM AUTHOR]

The water pollution due to tannery industries that contaminate river water and other spheres, is a side effect of industry expansion. The research focused on the biological removal of synthetic azo dyes by using biological treatment under aerobic conditions. Through morphological observation, biochemical test, and 16S rRNA sequence analysis the isolated bacteria were determined to be Aeromonas caviae, Enterobacter sichuanensis. Reduction of the organic content present in the tannery effluent and removal of the nutrients that cause pollution or inactivate potential pathogenic microorganisms or parasites. Optimized the azo dye degradation conditions at the temperature of 37°C, at pH 7 in 10% inoculum concentration at the time of 48th hour where novel organism capable of performing effective degradation. The metabolite of an aliquot mixture of the optimized condition was analyzed using Fourier Transform Infrared (FTIR) and the results confirmed the reduction of azo dyes. These results indicate that A. caviae and E. sichuanensis can be utilized as a solution for the remediation of tannery industrial effluent containing azo dyes. [ABSTRACT FROM AUTHOR]

AbstractThe current work is directed to study the synthesis of nanostructured polypyrrole (PPy) using an azo dye as a soft template. The as-prepared PPy was applied for the adsorption of methylene blue (MB) dye. The influence of the synthesis conditions on the morphology of the synthesized nanostructured PPy was examined. Different analytical tools were used for characterization of the synthesized nanostructured PPy. The surface area of the as-prepared nanostructured PPy was measured to be 30 m2 g−1 and hence it was applied for the adsorption of MB as a model of organic dyes. The influence of different parameters on the adsorption/removal of MB was investigated. It was found that the alkaline medium enhances the adsorption rate and the adsorption capacity. Upon increasing the system temperature, the adsorption capacity of nanostructured PPy toward MB dye increased. Different kinetic models were studied, and the current system was found to follow pseudo-second order as well as intraparticle diffusion kinetic models. The equilibrium data were examined by applying Langmuir, Freundlich, and Tempkin isotherms and the first model preferably described MB dye adsorption onto the nanostructured PPy. Reusability of the synthesized nanostructured PPy for the adsorption of MB dye was investigated for many cycles. [ABSTRACT FROM AUTHOR]

In the present study, silver nanoparticles were synthesized via green synthesis using fenugreek (Trigonella foenum‐graecum L.) seeds of variety HM 425. The AgNPs were characterized by using UV‐Visible spectroscopy, Particle size analyzer, Field emission scanning electron microscopy coupled to Energy dispersive X‐ray spectroscopy, XRD, High resolution transmission electron microscopy and Fourier Transform Infrared Spectroscopy. The AgNPs were spherical and had an average particle size of 28 nm. The reduction of cationic dyes Methylene blue, Rhodamine B, and an anionic azo dye Methyl Orange by Sodium borohydride was used as a model reaction to investigate the catalytic ability of AgNPs. The results demonstrated an efficient catalytic dye degradation of methylene blue (95.81 %, 25 min, 0.1737±0.01 min−1), Rhodamine B (90.23 %, 15 min, 0.1388±0.01 min−1) and methyl orange (83.63 %, 39 min, 0.0412±0.002 min−1). The synthesized AgNPs had an excellent detection limit of 12.50 μM for Hg2+, making them excellent solid bio‐based sensors for mercury sensing. [ABSTRACT FROM AUTHOR]

In this work, a novel colorimetric chemosensor (BIAD) containing azo chromophore, 1,5dihydroxynaphthalene, and benzimidazole was synthesized and characterized by using IR, 1H,13C NMR, and mass spectral data, and elemental analysis. The cation recognition studies (including fourteen metal cations) exhibited that the synthesized azo dye can act as a rapid, sensitive, and selective colorimetric chemosensor for detecting Cu2+ ions. The addition of Cu2+ ions to the BIAD solution, changed immediately the solution color from purple to blue‐green, which could be observed by the naked eye. Comparison of the UV/Visible spectra of BIAD and (BIAD+Cu2+) revealed a red shift from 543 nm to 616 nm, which confirms the formation of a complex between Cu2+ cations and BIAD molecules. The result of Job's plot indicated that the stoichiometry binding ratio of BIAD to Cu2+ is 1 : 1. The limit of detection (LOD) was found for BIAD toward Cu2+ ion to be 0.10 μM. Furthermore, the BIAD‐based test paper strips were successfully used for the rapid detection of Cu2+ ions (<1 sec) in the aqueous solution (H2O‐DMSO, 9 : 1). [ABSTRACT FROM AUTHOR]

This study investigates the solvatochromic behavior of a new D1 disperse dye, focusing on the 4-nitro-2-cyano-azo-Benzene-metaToluidine type. Using UV-visible spectroscopy, we analyze the dye's performance in single solvents and binary mixtures. Our analysis includes the evaluation of solvent polarity parameters and dye structure parameters, with emphasis on the longest wavelength intramolecular charge transfer absorption band. We identify nonlinear and linear patterns in the electronic transition energies plots with respect to solvent composition. Statistical analysis considers correlation coefficients, root mean squared error, mean absolute percentage error, and other parameters, providing insights into data accuracy and precision. This experimental and statistical study explores the absorption spectrum, wavelength characteristics, absorption energy, and polarity of a novel azo dye across various solvent and solute environments. These findings contribute to a comprehensive understanding of the dye's photophysical and photochemical properties, potentially enabling applications in optical sensors and advanced materials. [ABSTRACT FROM AUTHOR]

In the present study, silver nanoparticles were synthesized via green synthesis using fenugreek (Trigonella foenum‐graecum L.) seeds of variety HM 425. The AgNPs were characterized by using UV‐Visible spectroscopy, Particle size analyzer, Field emission scanning electron microscopy coupled to Energy dispersive X‐ray spectroscopy, XRD, High resolution transmission electron microscopy and Fourier Transform Infrared Spectroscopy. The AgNPs were spherical and had an average particle size of 28 nm. The reduction of cationic dyes Methylene blue, Rhodamine B, and an anionic azo dye Methyl Orange by Sodium borohydride was used as a model reaction to investigate the catalytic ability of AgNPs. The results demonstrated an efficient catalytic dye degradation of methylene blue (95.81 %, 25 min, 0.1737±0.01 min−1), Rhodamine B (90.23 %, 15 min, 0.1388±0.01 min−1) and methyl orange (83.63 %, 39 min, 0.0412±0.002 min−1). The synthesized AgNPs had an excellent detection limit of 12.50 μM for Hg2+, making them excellent solid bio‐based sensors for mercury sensing. [ABSTRACT FROM AUTHOR]

Photo-galvanic cell is a photochemical cell device whose performance depends on the combination of several factors like dye and reductant concentrations, dye stability, pH, light intensity, electrodes used, Pt electrode area, diffusion length, etc. An entirely new and unexplored combination of platinum with Allura Red photosensitizer, d-Galactose reductant, and didecyl dimethyl ammonium chloride (DDAC) surfactant has been explored in present research to upgrade the electrical performance of these cells. Allura Red is a water-soluble azo dye which shows good absorbance in region 501–507 nm. The Allura Red and DDAC is an anionic and cationic species, respectively, and therefore, the opposite charges of dye and surfactant molecules are expected to form a stable dye-surfactant complex enhancing the dye solubility and stability. d-Galactose has been used for its good reducing properties. This unexplored combination of Pt-Allura Red-d-Galactose-DDAC with these characteristics has encouraged further enhancement of the electrical output of the photogalvanic cells. The electrical output, stability, and spectral property of the photogalvanic cells have been studied in the present work. The observed power, current, potential, efficiency, and storage capacity (as half time) are of the order of 443.8 µW, 2400 µA, 721 mV, 11.61%, and 28 min, respectively. These observed results are higher than some reported data. In the spectral study, nearly the same band intensity of the pre-illuminated and post-illuminated electrolyte solution shows quite good photo-stability of the Allura Red dye in electrolyte form. This new combination of platinum-electrolyte still has the scope to achieve the enhanced cell performance of photogalvanic cells for future development. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4), known for being nontoxic, highly stable, and environmentally friendly, is extensively used in photocatalytic degradation technologies. Silver nanoparticles effectively capture the photogenerated electrons in g-C3N4, enhancing the photocatalytic efficiency. This study primarily focused on synthesizing graphitic carbon nitride via thermal polymerization and depositing noble metal silver onto g-C3N4 through photoreduction. Methyl orange (MO) and methylene blue (MB) were targeted as the pollutants in the photocatalytic experiments under visible light in conjunction with a H2O2 system. The characteristics peaks, structure, and morphology were analyzed using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). g-C3N4 loaded with 6% Ag exhibited superior photocatalytic performance; the photocatalytic fraction of the degraded materials of the MO and MB solutions reached 100% within 70 and 80 min, respectively, upon adding 1 mL and 2 mL of H2O2. ·OH and ·O2− were the primary active free radicals in the dye degradation process within the synergistic system. Stability tests also demonstrated that the photocatalyst maintained good reusability under the synergistic system. [ABSTRACT FROM AUTHOR]

Reactive black 5 (RBk5) is a refractory azo dye that constitutes a serious threat to the environment and humans. Herein, natural bornite (Nbo) was utilized to activate persulfate (PDS) for the RBk5 removal. The particle size of the Nbo catalyst was optimized and the RBk5 degradation rate constant that responded positively to the particle size of the Nbo catalyst was exhibited. Then, the operational factors affecting RBk5 removal were comprehensively investigated. With the addition of 1.5 g L−1 Nbo and 1.5 mM PDS, 99.05% of the RBk5 (20 mg L−1) was removed in 150 min compared with 0.46% removal with PDS only, which was caused by the additional reactive oxygen species (ROS) produced by the synergistic action of Fe-Cu bimetallic metal and reductive sulfur species. The Nbo catalyst presented high stability and reusability toward RBk5 removal. Identification of reactive oxygen species revealed that ${\rm SO}_4^{\cdot -}$ SO 4 ⋅ − , ·OH, ${\rm O}_2^{\cdot -}$ O 2 ⋅ − and 1O2 collectively participated in RBk5 removal. Additionally, a possible degradation pathway for RBk5 was proposed, including cleavage of the azo, C–S and S–O bonds, hydroxylation, hydrolyzation, direct oxidation and other pathways. This work developed a highly effective and low-cost natural mineral-based bimetallic sulfide material for PDS activation for the degradation of contaminants and environmental remediation. [ABSTRACT FROM AUTHOR]

Oxalate plays a crucial role in various biological and industrial applications. Its involvement in diseases, drug‐ and toxin‐induced disorders, and disruption of industrial processes makes it a high‐priority chemical for the development of more precise, selective, and straightforward analytical methods. Herein, an innovative and efficient strategy for sequentially measuring Cu2+ and oxalate ions is reported. During an indicator displacement process, where Cu2+ and azo dye, ArsenazoIII (AAIII), are used as receiver and indicator, respectively, oxalate (C2O42−) is measured by a colorimetric method. Proof of concept results from UV–visible spectroscopy, naked eye, and signal reset of the indicator revealed a more robust interaction of the Cu2+ receptor with C2O42− than the AAIII indicator with high selectivity, good sensitivity, and lower detection limit(4.01 × 10−8 and 3.04 × 10−9mol L−1, for Cu2+ and C2O42−, respectively). The results of measuring C2O42− in actual samples (urine, mushrooms, and spinach) showed the applicability of the existing method. Most importantly, the colorimetric system based on molecular exchange in the indicator dislocation proceeding can serve as a colorimetric INHIBIT logic‐gate. It works like a molecular keypad lock system that can be controlled by two users with two different sets of chemical passwords (inputs) that can be identified through optical paths. [ABSTRACT FROM AUTHOR]

Azo dye-laden textile wastewater must be treated before release due to various health and environmental concerns. Bioremediation of textile wastewater, however, is a challenge owing to its alkaline and saline nature as mesophilic microbes, in general, are either not able to thrive or show less efficiency under such hostile environment. Thus, pre-treatment for neutralization or salinity removal becomes a prerequisite before applying microbes for treatment, causing extra economical and technical burden. Extremophilic bacteria can be the promising bioremediating tool because of their inherent ability to survive and show toxicants removal capability under such extreme conditions without need of pre-treatment. Among extremophiles, halophilic and alkaliphilic bacteria which are naturally adapted to high salt and pH are of special interest for the decolorization of saline-alkaline-rich textile wastewater. The current review article is an attempt to provide an overview of the bioremediation of azo dyes and azo dye-laden textile wastewater using these two classes of extremophilic bacteria. The harmful effects of azo dyes on human health and environment have been discussed herein. Halo-alkaliphilic bacteria circumvent the extreme conditions by various adaptations, e.g., production of certain enzymes, adjustment at the protein level, pH homeostasis, and other structural adaptations that have been highlighted in this review. The unique properties of alkaliphiles and halophiles, to not only sustain but also harboring high dye removal competence at high pH and salt concentration, make them a good candidate for designing future bioremediation strategies for the management of alkaline, salt, and azo dye-laden industrial wastewaters. [ABSTRACT FROM AUTHOR]

As the aim of all researcher in the field of water purification, is to develop new materials with high reactivity this study took the advance to apply the hybrid Ca(OH)2/Ag nanocomposite which is not used very often in this filed for the catalytic reduction of various types of dyes separately and in a mixture to assess their ability and effectiveness under contact with direct sunlight. The catalytic degradation of dyes was considered under various conditions: with and without adding reducing agent, and with and without applying sun light to evaluate the reductive ability of the catalyst under study at all conditions. The prepared Ca(OH)2/Ag hybrid nanocomposite, examined by XRD and TEM to study their morphology size and shape and to prove the presence of both nanoparticles Ca(OH)2 and Ag and the results showed a high crystalline structure with an average particle size of 10.9 nm nanoparticles formed. The results of degradation of all dyes under test (acidic green dye 25 (AGD25), orange direct dye (ODD), and basic blue dye 41(BBD41)) showed that under applying the Ca(OH)2 nanoparticles only the degradation percentage reached nearly 84, 67, 73.8% respectively, after 24 h. The primed nanocomposite Ca(OH)2/Ag exhibited an unusual ability to reduce all various tested dyes by using 0.2 g of prepared hybrid nanocatalyst, which was adequate to degrade a 50 ml solution of 200 mg/L concentration of each dye after nearly 60 min, this time differs somewhat with varying the type of dye where the degradation percentage reached 98, 90, and 97% for AGD25, ODD, and BBD41, respectively. The results revealed that the acid green 25 dye (AGD25) had the most significant degradation percentage compared with the other tested dyes, which grasped to 98% after only 60 min. Also, the degradation experiment carried out under various factors as initial concentration of dye, amount of catalyst, and temperature and the results showed that increasing the amount of catalyst and temperature enhances the degradation pf AGD25 to completion. [ABSTRACT FROM AUTHOR]

In this work, the role of ascorbic acid in the process of azo dye degradation was explained. For this purpose, the kinetics of azo dye degradation under different conditions was studied. Among them, the influence of daylight protection/exposition, different concentrations of ascorbic acid (0.567–0.014 mol/dm3), and temperature (20 °C and 50 °C) on the rate of the dyes' degradation was considered. For this process, the kinetic equation was proposed, which indicates that the process of azo dye degradation using ascorbic acid is first order. Moreover, the observed rate constants were determined, and the mechanism of azo dye degradation was proposed. Spectrophotometry results, together with FTIR, fluorescence spectroscopy, and DFT calculations, explain the origin of the decolorization of the azo dyes and highlight the role of ascorbic acid in this process. Detailed analysis of the obtained products indicates that the process itself goes through several stages in which equally or more toxic compounds are formed. Obtained results from LCMS studies indicate that during tropaeolin OO degradation, 1,2-Diphenylhydrazine (m/z 185.1073) is formed. Thus, the process of azo dye degradation should be carried out in protective conditions. The proposed mechanism suggests that ascorbic acid at high content levels can be used for azo dye degradation from aqueous solution and can be an alternative method for their removal/neutralization from waste solution but with caution during the process. [ABSTRACT FROM AUTHOR]

A novel electrochemical sensor was designed by using a synthesized anthraquinone azo dye-based glassy carbon electrode was fabricated and used for enhanced selective determination of Dopamine (DA) and serotonin (5-HT) simultaneously at an optimum working potential (0.11 V for DA and 0.27 V for 5-HT). Utilizing spectroscopic techniques like FT-IR, HR-MS, and 1H-NMR, a synthesized azo dye molecule structure was characterized. Different electrochemical techniques, including cyclic voltammetry (CV) and differential pulse voltammetry (DPV), were employed to study the electrochemical sensing abilities of the modified working electrode. The DA and 5-HT linear response ranges between current intensities and concentration were found to be 0.001–0.055 and 0.01–1.15 µM and the lower limit of detection (LOD) was 1.9 and 4.16 nM respectively. Further demonstrating the constructed electrochemical sensor's practical application were tests of reproducibility, stability, and real sample analysis with excellent recovery. [ABSTRACT FROM AUTHOR]

Grouping/read-across is widely used for predicting the toxicity of data-poor target substance(s) using data-rich source substance(s). While the chemical industry and the regulators recognise its benefits, registration dossiers are often rejected due to weak analogue/category justifications based largely on the structural similarity of source and target substances. Here we demonstrate how multi-omics measurements can improve confidence in grouping via a statistical assessment of the similarity of molecular effects. Six azo dyes provided a pool of potential source substances to predict long-term toxicity to aquatic invertebrates (Daphnia magna) for the dye Disperse Yellow 3 (DY3) as the target substance. First, we assessed the structural similarities of the dyes, generating a grouping hypothesis with DY3 and two Sudan dyes within one group. Daphnia magna were exposed acutely to equi-effective doses of all seven dyes (each at 3 doses and 3 time points), transcriptomics and metabolomics data were generated from 760 samples. Multi-omics bioactivity profile-based grouping uniquely revealed that Sudan 1 (S1) is the most suitable analogue for read-across to DY3. Mapping ToxPrint structural fingerprints of the dyes onto the bioactivity profile-based grouping indicated an aromatic alcohol moiety could be responsible for this bioactivity similarity. The long-term reproductive toxicity to aquatic invertebrates of DY3 was predicted from S1 (21-day NOEC, 40 µg/L). This prediction was confirmed experimentally by measuring the toxicity of DY3 in D. magna. While limitations of this 'omics approach are identified, the study illustrates an effective statistical approach for building chemical groups. [ABSTRACT FROM AUTHOR]

Objective: Due to wide range of biological activities exhibited by pyran derivatives such as antibacterial, antioxidant, anticancer and other activities, we have synthesized and investigated the biological activity of some pyran derivatives. Methods: A series of 4-hydroxy-6-methyl-5,6-dihydro-2H-pyran-2-one based azo dyes (IIIa–IIIf) have been synthesized by a conventional diazo coupling reaction. The antioxidant activity was determined via DPPH assay and Antimicrobial activity through disc diffusion test. Results and Discussion: Compound (IIIb) has shown excellent radical scavenging activity with an IC50 value of 20.22 ± 7.36 µg/mL compared to the standard. Furthermore, compounds (IIIc) and (IIId) showed a good antibacterial and antifungal activity against Escherichia coli and Aspergillus niger compared to other prepared azo compounds. Conclusions: We propose that in future, synthesized compounds may act as a promising antimicrobial drugs. [ABSTRACT FROM AUTHOR]

The present work reports the synthesis of cobalt ferrite and its nanohybrids with polythiophene (PTh) in the weight ratios of 10% and 20%. The ferrite and its nanohybrids were characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy coupled with elemental mapping (Fe-SEM) to confirm the morphology as well as the structure of the synthesized nanohybrids. The nanohybrids were tested for their photocatalytic activity upon modification of PTh against Alizarin Yellow (AY), Congo Red (CR) and Brilliant Blue (BB). Almost 100% degradation was achieved in 30 min using 50 mg of the photocatalyst. The effect of catalyst concentration and dye concentration was also investigated to explore optimum concentration of the photocatalyst required for rapid degradation of the dye. The generation of radicals responsible for degradation was analyzed by radical scavenging experiments and a probable mechanism of degradation was proposed. [ABSTRACT FROM AUTHOR]

A simple method for purifying water using household items has been developed. The solution containing an environmental pollutant was added to the PET bottle. The lid of the PET bottle was closed, and the bottle was then placed with the lid down in a freezer for 9 h. The pourer of the PET bottle was surrounded by shredded paper scraps as a lagging material. Before the solution was completely frozen, the sample was removed from the freezer. The unfrozen portion (liquid) was sampled. The pollutant was concentrated in the liquid. The remaining frozen portion was completely thawed. As results, the concentration of the pollutant (Congo Red, Cr (VI), Pb (II), pentachlorophenol, fluoride, nitrate, or phosphate) in the thawed liquid was decreased by more than 90% compared with the initial concentration (0.10 mM). Practitioner Points: A pollutant in a water sample can be removed by freezing a portion of the solution using a PET bottle, shredder scrap, and household freezer.Fluorine and hexavalent chromium can be removed from water to levels that meet water quality standards.The present method can efficiently remove a wide range of contaminants from water, including azo dyes, heavy metals, and pentachlorophenol. [ABSTRACT FROM AUTHOR]

Chitosan is a good adsorbent but has poor effectiveness against some dyes. Therefore, in this study, we synthesized composite materials of prepared crab shell chitosan with ZnO and PVA to improve adsorption efficiency. The ZnO/CTS and ZnO/PVA/CTS composites were synthesized by dissolving the components into a solution with the help of ultrasound and hydrothermally neutralizing it for 3 h. The obtained composites and crab shell chitosan were characterized by methods such as GPC, FTIR, XRD, and SEM. Adsorption experiments were conducted in batch form and only sampled once under each condition. The results showed the molecular weight of crab shell chitosan is around 105 g/mol and quite homogenous in size, and the embedded nanorod-like ZnO in the composite is around 200 nm in sizes. The adsorption of the dyes Indigo Carmine (IC), Alizarin Yellow (AY), and Thymol Blue (TB) onto the composites was highest compared to the single adsorbent and ranked in descending order: ZnO/CTS+AY > ZnO/PVA/CTS+IC > ZnO/CTS+IC > ZnO/PVA/CTS+AY > ZnO/CTS+TB > ZnO/PVA/CTS+TB, which corresponds to qmax of 285.7 mg/g, 227.3 mg/g, 208.3 mg/g, 188.7 mg/g, 60.6 mg/g, and 50.3 mg/g, respectively. In addition, the adsorption kinetics of all cases followed the pseudo-second-order adsorption model, it implies that the rate of adsorption is proportional to the square of the number of unoccupied sites. [ABSTRACT FROM AUTHOR]

In this work, we employ an eco-friendly and highly efficient method for the successful removal of anionic azo dye (CR) using emerging Ni/Co-BTC hollow Metal-Organic Frameworks (MOFs). The MOFs was developed via a solvothermal synthesis method. Various kinetic models, adsorption capacities, isotherms (Langmuir and Freundlich), and thermodynamic stability assessments were used to predict the adsorption mechanism and the types of interactions present between CR dyes and Hollow MOFs. Our findings suggest that the adsorption process follows Freundlich isotherm, with PSO kinetic models indicating chemisorption and a maximum Langmuir adsorption capacity of 168.03 mgg−1. We observed a removal efficiency of 74% in neutral medium and 85% in acidic medium. Thermodynamic studies reveal the spontaneity of the process with endothermic enthalpy, attributed to the hydrogen bonding and electrostatic interactions between the dye molecule and the adsorbent. Furthermore, to investigate practical applicability, we conducted studies in real water and dye mixtures. All studies demonstrated that the prepared Ni/Co-BTC hollow MOFs show promising potential adsorbents for the CR dye removal from the wastewater, owing to their high efficiency and reusability. Adsorption of anionic dyes in hollow MOFs High adsorption capacity obtained from adsorption isotherm studies High efficiency for Congo red and mixture of dyes Adsorption process is highly spontaneous and endothermic [ABSTRACT FROM AUTHOR]

2-Methyl-4-nitroaniline (MNA), an intermediate in the synthesis of azo dyes, is widely distributed in various environmental media and organisms. Although there is speculation regarding MNA's potential to be hepatotoxic, the underlying mechanisms of its hepatotoxicity and its definitive diagnostic process remain largely unexplored. In this research. In the present study, we initially predicted the toxicity and possible toxic effect pathways of MNA using ProTox-II, and found that MNA binds to the PPARγ receptor (binding energy －6.118 kcal/mol) with a potential PPARγ agonist effect. Subsequently, in vivo exposure evaluation was conducted on Wistar rats to assess the impact of MNA after a 90-day exposure period, by detecting serum biochemical indexes, hematological indexes, urinary indexes, inflammatory factors, liver histopathological observations and liver tissue PPARγ mRNA expression. The results showed that MNA causes liver function abnormalities, liver histopathological changes and inflammatory response, along with a pronounced increase in PPARγ mRNA levels. This study suggests that the hepatotoxic mechanism of MNA may be related to its possible upregulation of PPARγ expression, increased liver dysfunction and inflammatory responses. Based on these results, the benchmark dose lower limit (BMDL) of 1.503 mg/kg for male Wistar rats was also established, providing a vital benchmark for determining the safety threshold of MNA. Our data highlight the hepatotoxic mechanism of MNA and contribute to a better understanding of its potential etiological diagnosis. [Display omitted] • MNA causes liver histopathological changes, dysfunction and inflammatory response. • MNA binds to the PPARγ receptor and upregulates PPARγ mRNA expression. • The BMDL value of 1.503 mg/kg for MNA in male Wistar rats was determined. [ABSTRACT FROM AUTHOR]

Batteries are one of many types of solid waste. Once utilized, they are considered and categorized as 'hazardous waste' since they can cause major problems if unlawfully disposed of. The synthesis of ZnO nanoparticles using eco-friendly methods and their application in photocatalysis is crucial due to the environmental and economic benefits of recycling Zn plates from waste batteries. This innovative approach not only offers a sustainable solution for waste management but also presents an opportunity to harness the photocatalytic properties of ZnO nanoparticles for various environmental remediation applications, thereby contributing to the advancement of green nanotechnology and sustainable development. This study aims to address environmental concerns associated with battery waste and water pollution by proposing a sustainable and innovative approach. The focus is on recycling zinc plates from discarded batteries and synthesizing zinc oxide (ZnO) nanoparticles using eco-friendly methods. In this study, ZnO nanoparticles were synthesized on the Zn plates isolated from waste batteries by reacting the plates in the presence of hydrogen peroxide. SEM and EDS were used to characterize the final ZnO-coated Zn plate. The presence of ZnO nanoparticles with small spherical forms and modest diameter variation on the Zn plate was confirmed by SEM data. Furthermore, the photocatalytic treatment of azo dyes with the obtained ZnO-coated Zn plates was examined. The investigation yielded degradation rates of 72.7% and 57.4% for Remazol Brillant Blue R (RBBR) and Basic Red 18 (BR 18), respectively. Results demonstrate the potential of the ZnO-coated Zn plates as effective photocatalysts, highlighting their role in promoting sustainability in both waste management and water treatment. This work contributes to advancing eco-friendly technologies and underscores the importance of sustainable practices in addressing contemporary environmental challenges. [Display omitted] • Zn plates were recycled from waste batteries and utilized in water treatment. • ZnO nanoparticles were synthesized on the surface of Zn plates using eco-friendly methods. • The photocatalytical activity of nano ZnO-coated plates was excellent. • The catalyst can be easily separated from the system after the procedure. • RBBR and BR 18 dyes were degraded by 72.7% and 57.4%, respectively. [ABSTRACT FROM AUTHOR]

Environmental pollution, particularly from textile industry effluents, raises concerns globally. The aim of this study is to investigate the hepatotoxicity of Sudan Black B (SBB), a commonly used textile azo dye, on embryonic zebrafish. SBB exposure led to concentration-dependent mortality, reaching 100% at 0.8 mM, accompanied by growth retardation and diverse malformations in zebrafish. Biochemical marker analysis indicated adaptive responses to SBB, including increased SOD, CAT, NO, and LDH, alongside decreased GSH levels. Liver morphology analysis unveiled significant alterations, impacting metabolism and detoxification. Also, glucose level was declined and lipid level elevated in SBB-exposed in vivo zebrafish. Inflammatory gene expressions (TNF-α, IL-10, and INOS) showcased a complex regulatory interplay, suggesting an organismal attempt to counteract pro-inflammatory states during SBB exposure. The increased apoptosis revealed a robust hepatic cellular response due to SBB, aligning with observed liver tissue damage and inflammatory events. This multidimensional study highlights the intricate web of responses due to SBB exposure, which is emphasizing the need for comprehensive understanding and targeted mitigation strategies. The findings bear the implications for both aquatic ecosystems and potentially parallels to human health, underscoring the imperative for sustained research in this critical domain. [ABSTRACT FROM AUTHOR]

Dye contamination in printing and dyeing wastewater has long been a major concern due to its serious impact on both the environment and human health. In the quest for bioremediation of these hazardous dyes, biological resources such as biodegradation bacteria and enzymes have been investigated in severely polluted environments. In this context, the triphenylmethane transporter gene (tmt) was identified in six distinct clones from a metagenomic library of the printing and dyeing wastewater treatment system. Escherichia coli expressing tmt revealed 98.1% decolorization efficiency of triphenylmethane dye malachite green within 24 h under shaking culture condition. The tolerance to malachite green was improved over eightfold in the Tmt strain compared of the none-Tmt expressed strain. Similarly, the tolerance of Tmt strain to other triphenylmethane dyes like crystal violet and brilliant green, was improved by at least fourfold. Site-directed mutations, including A75G, A75S and V100G, were found to reinforce the tolerance of malachite green, and double mutations of these even further improve the tolerance. Therefore, the tmt has been demonstrated to be a specific efflux pump for triphenylmethane dyes, particularly the malachite green. By actively pumping out toxic triphenylmethane dyes, it significantly extends the cells tolerance in a triphenylmethane dye-rich environment, which may provide a promising strategy for bioremediation of triphenylmethane dye pollutants in the environments. [ABSTRACT FROM AUTHOR]

This work includes synthesis of the novel azo compound, which consists of diazotization of 3-nitroaniline followed by reaction with 4-hydroxybenzaldehyde in presence of sodium carbonate. The syanthesized azo compound was confirmed by characterization, using FT-IR, ¹HNMR, 13CNMR and GC-MS spectra. The azo compound was screened for solvatochromism, Halochromism using UV-Vis spectrophotometer, and found that the azo compound exhibited low solvatochromic and good Halochromic properties. While the dying study (Dye-doped Polymer Films), Poly ethylene was found the best polymer dyed by azo compound and showed good absorbance in the UV region. All fabrics were dyed with a yellow color except the cotton exhibiting a light brown color. [ABSTRACT FROM AUTHOR]

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Trace concentrations of dyes are often present in textile wastewater streams and present a serious environmental problem. Thus, these dyes must be removed from wastewater either by degradation or sequestration prior to discharge of the wastewater into the environment. Existing processes to remove these wastewater contaminants include the use of solid sorbents to sequester dyes or the use of biochemical or chemical methods of dye degradation. However, these processes typically generate their own waste products, are not necessarily rapid because of the low dye concentration, and often use expensive or non-recyclable sequestrants or reagents. This paper describes a simple, recyclable, liquid–liquid extraction scheme where ionic dyes can be sequestered into poly(α-olefin) (PAO) solvent systems. The partitioning of anionic and cationic dyes from water into PAOs is facilitated by ionic PAO-phase anchored sequestering agents that are readily prepared from commercially available vinyl-terminated polyisobutylene (PIB). This is accomplished by a sequence of reactions involving hydroboration/oxidation, conversion of an alcohol into an iodide, and conversion of the resulting primary alkyl iodide into a cationic nitrogen derivative. The products of this synthetic sequence are cationic nitrogen iodide salts which serve as anionic sequestrants that are soluble in PAO. These studies showed that the resulting series of cationic PIB-bound cationic sequestering agents facilitated efficient extraction of anionic, azo, phthalein, and sulfonephthalein dyes from water into a hydrocarbon PAO phase. Since the hydrocarbon PAO phase is completely immiscible with water and the PIB derivatives are also insoluble in water, neither the sequestration solvent nor the sequestrants contaminate wastewater. The effectiveness and efficiency of these sequestrations were assayed by UV–visible spectroscopy. These spectroscopic studies showed that extraction efficiencies were in most cases >99%. These studies also involved procedures that allowed for the regeneration and recycling of these PAO sequestration systems. This allowed us to recycle the PAO solvent system for at least 10 sequential batch extractions where we sequestered sodium salts of methyl red and 4′,5′-dichlorofluorescein dyes from water with extraction efficiencies of >99%. These studies also showed that a PIB-bound derivative of the sodium salt of 1,1,1-trifluoromethylpentane-2,4-dione could be prepared from a PIB-bound carboxylic acid ester by a Claisen-like reaction and that the sodium salt of this β-diketone could be used to sequester cationic dyes from water. This PIB-bound anion rapidly and efficiently extracted >99% of methylene blue, malachite green, and safranine O from water based on UV–visible and 1H NMR spectroscopic assays. [ABSTRACT FROM AUTHOR]

BACKGROUND: Anthraquinone dyes have an anthraquinone structure as their nucleus, with one or more substituents forming different organic dyes. Anthraquinone dyes have a complex structure that allows them to exist stably in water environment, but also makes them more toxic than azo dyes. This results in varying degrees of harm to both humans and the environment as a result of residual dyes in the water or on the material' surface. Sodium percarbonate (SPC) is a highly promising oxidant due to its green end product. Therefore, in this study, the catalytic performance and kinetic study of cobalt oxide (CoO) on SPC under different conditions were systematically investigated using RB19 as the target pollutant. The Box–Behnken Design (BBD) model was used to model the degradation of RB19 by CoO/SPC system, which gives the basis for practical application. The types of reactive oxygen species that effectively degrade RB19 and the potential degradation mechanism of the CoO/SPC system were revealed. At the same time, the CoO/SPC system was evaluated in terms of its practicality. RESULTS: In this work, the activation of SPC using CoO towards reactive blue 19 (RB19) degradation was explored. Experimental results showed that nearly 93.8% of RB19 could be removed within 30 min using 1 mmol L−1 SPC and 30 mg L−1 CoO. The three‐factor interaction effects of SPC concentration, CoO dosage and initial pH were investigated. The BBD model was set up to obtain the optimum working conditions of 1.039 mmol L−1 SPC, 33.35 mg L−1 CoO and the initial pH of 7.82, which gave a degradation rate of 95.372%. Additionally, it was confirmed that the solubility of Co2+ is consistently <150 μg L−1, meeting the emission standard (1 ppm). The presence of Cl−, NO3–, and HA had a similar profile, with a slight promoting effect in small amounts and an inhibitory effect when introduced in excess. The introduction of SO42– had a negligible effect on RB19 degradation, whereas the presence of HCO3− produced a slight inhibitory effect. Furthermore, the presence of PO43– showed a strong inhibitory effect. The CoO/SPC system is suitable for other organic dyes (32.7%–100%) and antibiotics (97.1–100%). Electron paramagnetic resonance (EPR) analysis and quenching experiments confirmed the presence and relative contribution of free radicals in the CoO/SPC system as CO3•‐ (88.12%) >O2•‐ (51.11%) >1O2 (37.21%) >•OH (5.27%) > SPC (3.33%) >CoO (0.09%). It has been confirmed that CoO activates SPC through electron transfer. CONCLUSION: The present study describes a less time‐consuming, and more efficient method of treating anthraquinone dye wastewater that requires less oxidizer and catalyst, making it more economical. This proposes a straightforward, cost‐effective and efficient technique using SPC triggered by transition metal oxides. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Water pollution caused by dyes is a significant environmental issue, necessitating the development of effective, cost-efficient decolorization methods suitable for industrial use. In this study, a Chitosan-Fe polymeric gel was synthesized, characterized, and tested for removing the azo dye Direct Red 83:1 from water. The polymeric magnetic chitosan was analyzed using various techniques: Field Emission Scanning Electron Microscopy (FE-SEM) revealed a porous structure, Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) demonstrated the thermal stability, Infrared Spectrophotometry (IR) indicated the successful coordination of iron at the C3 position, and X-ray Powder Diffraction (XRD) confirmed the crystalline nature of the polymeric structure. Optimal conditions for kinetic and isotherm models were found at 1 g and pH 7.0. Adsorption behavior of Direct Red 83:1 onto magnetic chitosan gel beads was studied through kinetic tests and isotherm curves. The maximum adsorption capacity was 17.46 mg/g (qmax). The adsorption process followed pseudo-second-order kinetics (R2 = 0.999) and fit the Temkin isotherm (R2 = 0.946), suggesting heterogeneous surface adsorption. The newly synthesized Chitosan-Fe polymeric gel demonstrated good adsorption properties and facilitated easy separation of purified water. [ABSTRACT FROM AUTHOR]

Hollow mesoporous hydroxyapatite (HM-HAP) composites coated with titania are prepared to increase the stability and catalytic performance of titania for azo dyes present in the wastewater system. In this work, HM-HAP particles were first synthesized by a hydrothermal method utilizing the CaCO3 core as a template and then coated with titania to form TiO2/HM-HAP composites. Utilizing SEM, XRD, XPS, BET, FTIR, EDS, UV–vis DRS spectroscopy, and point of zero charge (PZC) analysis, the coating morphological and physicochemical parameters of the produced samples were analyzed. The photocatalytic efficiency of the synthesized coated composites was assessed by the degradation of methyl red (MR) dye in water. The results indicated that TiO2/HM-HAP particles could efficiently photodegrade MR dye in water under UV irradiation. The 20% TiO2/HM-HAP coating exhibited high catalytic performance, and the degradation process was followed by the pseudo-first-order (PFO) kinetic model with a rate constant of 0.033. The effect of pH on the degradation process was also evaluated, and the maximum degradation was observed at pH 6. The analysis of degraded MR dye products was investigated using LC-MS and FTIR analysis. Finally, a good support material, HM-HAP for TiO2 coatings, which provides a large number of active adsorption sites and has catalytic degradation performance for MR dye, was revealed. [ABSTRACT FROM AUTHOR]

The current study was conducted to understand the sole role of graphite as a substrate material in a dual-chambered baffled electroactive wetland (EW) in the treatment of Methyl red dye-containing wastewater. The results obtained were compared with conventional gravel-based unplanted dual-chambered constructed wetlands (CW) at a lab scale. The highest dye decolorisation and COD removal efficiency achieved was 92.88 ± 1.6% and 95.78 ± 4.1%, respectively, in the electro-active wetland. Dissolved oxygen (DO) and pH conditions were appropriately maintained in both the microcosms because of separated aerobic and anaerobic chambers. UV–vis and gas chromatography-mass spectroscopy analysis revealed the production of by-products like 4-amino benzoic and N- N dimethyl phenyl-diamine of MR in microcosms and revealed further mineralisation of by-products in the aerobic zone of electroactive-wetland. Higher root growth of Cicer aerietinum and Vigna radiata was observed in the presence of effluents of baffled electroactive wetlands compared to constructed wetland, indicating a decrease in phytotoxicity. Metagenomic analysis revealed the abundance of potential microbes for MR and organic matter removal from phylum Proteobacteria, Firmicutes, Bacteroidetes, and Euryarchaeota. A batch adsorption study revealed a higher adsorption capability of graphite material in comparison to gravel. Hence, this study demonstrated that graphite is an appropriate substrate in electroactive wetland in facilitating microbial attachments and enhancing dye degradation, in addition to exhibiting superior adsorption quality. [ABSTRACT FROM AUTHOR]