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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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

Practical Application Food adulteration involving the illegal addition of dyes to foodstuffs has become an alarming issue in recent years. This study developed and validated a high‐performance liquid chromatography (HPLC)–DAD (diode array detector) method for the simultaneous determination of nine azo dyes (Butter Yellow, Sudan Orange G, Para Red, Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Red 7B, and Scarlet 808). Moreover, a qualitative analysis method using liquid chromatography–tandem mass spectrometry was developed to more accurately identify peaks detected in HPLC–DAD. The calibration curve represented good linearity (r2 ≥ 0.9998) over the measured concentration range of 0.5–25 mg/kg. limit of detection and limit of quantification were 0.01–0.04 and 0.04–0.12 mg/kg, respectively. Accuracy and precision were 96.0–102.6 and 0.16–2.01 (relative standard deviation%), respectively. Additionally, the measurement uncertainty and HorRat value were estimated. Several Curcuma longa L. distributed in Korea were collected and monitored for azo dye contaminants.The proposed HPLC–DAD method represents a significant advancement in the field, offering a reliable means of quantifying azo dyes and identifying their presence even at trace levels in adulterated turmeric. This not only contributes to ensuring the safety and integrity of turmeric products but also establishes precedent for robust analytical techniques in addressing food safety challenges. [ABSTRACT FROM AUTHOR]

Surface-active magnetic materials having suitable anchoring moieties have gained great interest in the field of environmental pollution management. Herein, 3,5-diaminobenzoic acid (DABA)-functionalized Fe3O4 (Fe3O4@DABA) nanoparticles were synthesized for adsorbing anionic pollutants from wastewater. First, Fe3O4 nanoparticles were fabricated via aqueous coprecipitation of Fe3+ and Fe2+ ions, and then, the bare-surface of Fe3O4 was functionalized concomitantly with DABA. The production of Fe3O4 particles and their surface functionalization with DABA, and the thermal stability of Fe3O4@DABA were confirmed using Fourier transform infrared spectroscopy and gravimetry. Core-Fe3O4 particles had a spinel structure, and their concurrent surface functionalization did not alter the initial phase purity of Fe3O4, as revealed by an X-ray diffraction study. Fe3O4@DABA particles showed nano-sized, spherical-shaped, improved surface morphology, surface area, surface porosity, and pH-dependent surface activities. Fe3O4@DABA nanoparticles exhibited a higher hydrodynamic average diameter and better aqueous dispersity than those of bare-Fe3O4. The saturation magnetization of Fe3O4@DABA was found to be 47 emu g−1 under ambient conditions. Our designed magnetic Fe3O4@DABA nanoadsorbent showed very high affinity towards the uptake of azo dye molecules: maximum adsorption of 259 mg g−1 for Congo red (CR) and 282 mg g−1 for Eosin yellow (EY) was reached at pH 3 and 25 °C by using an adsorbent dose of 0.02 g. Adsorption isotherm and kinetic study suggested both CR and EY adsorption followed the Freundlich adsorption model and pseudo-first-order kinetics. The adsorbed azo dye was eluted effectively from the surface of the investigated nanoadsorbent by aqueous alkali (0.1 M NaOH) treatment. In addition, Fe3O4@DABA showed excellent magnetic recyclability without considerable loss of adsorption capacity. After recycling five times, the adsorption efficiency of Fe3O4@DABA slightly declined (90.16% for CR, and 95.52% for EY) compared to that of the initial adsorption. [ABSTRACT FROM AUTHOR]

AbstractSince conventional dye removal techniques require a substantial amount of energy and chemicals, this study evaluated the utilization of Pleurotus ostreatus, a species of fungus, in an environmentally beneficial mycoremediation approach to decolorize two azo dyes, methyl orange (MO) and methyl red (MR), in a liquid medium. Pleurotus ostreatus was utilized under standard circumstances in the solutions containing 0.05% (w/v) MO and 0.05% (w/v) MR, without undergoing any genetic modifications. By analyzing the effects of time (6, 12, and 18 days), temperature (15 °C to 40 °C), pH (4 to 7), and inoculum volume (1 to 25 mL) on the decolorization rate of P. ostreatus, the ideal environment for the decolorization of MO and MR was determined. The highest rate of decolorization was evident at 25 °C temperature, pH 7 within 18 days of incubation, P. ostreatus could decolorize 0.05 g MO up to 97% when added in 10 mL inoculum volume on the other hand 0.05 g MR up to 93% in 15 mL inoculum volume at pH 6. Furthermore, the dye uptake rate after 18 days for MO was 59.25% and MR was 53.97% which indicated that P. ostreatus had a better uptake efficiency for MO than MR. Based on its ability to decolorize both MO and MR under suitable circumstances, the study concludes that P. ostreatus offers an appreciable mycoremediation approach for removing dye pigments from industrial wastewater. [ABSTRACT FROM AUTHOR]

Summary: In this study, the effects of citric acid‐loaded Hβ zeolite (F), activated clay and their modified decolorizers on the nutrients, volatile compounds and harmful substances of sesame oil in the decolorization process were evaluated. The results showed that the decolorization effect of F was second only to that of activated clay, the yield of F‐treated sesame oil sample was not significantly different from that of other decolorizers. The formation of asarinin was detected only in the sesame oil samples treated with F and H (zinc chloride‐activated clay). Compared with the activated clay‐treated sesame oil samples, the retention of tocopherols in the F‐treated sesame oil sample was significantly increased by 23.11%, and the retention of phytosterols was increased by 4.85%. The removal rate of the harmful substances Norharman and Harman in the F‐treated sesame oil sample was 96.79%, which was second only to that of the activated clay. Additionally, the removal rate of the total volatile compounds was the highest at 69.47%. The effects of different decolorizers on the sesame oil samples were closely related to the specific surface area, pore size and surface acidic sites of these decolorizers. This study could provide ideas for the industrial application of leached sesame oil, such as cosmetics and base oils. [ABSTRACT FROM AUTHOR]

The catalytic capabilities of metals in degrading azo dyes have garnered extensive interest; however, selecting highly efficient metals remains a significant challenge. We have developed a Zn-Ca-based metallic glass composite which shows outstanding degradation efficiency for Direct Blue 6. This alloy comprises a Zn2Ca crystalline phase and an amorphous matrix, allowing for the degradation of azo dyes within minutes in a wide temperature range of 0–60 °C. Kinetic calculations reveal an exceptionally low activation energy of 8.99 kJ/mol. The rapid degradation is attributed to the active element Ca and the unique amorphous structure of the matrix, which not only facilitates abundant redox conditions but also minimizes the hydrolysis of the active element. The newly developed metallic glass composite exhibits a notably higher azo dye degradation rate compared to those of general metallic glasses, offering a new avenue for the rapid degradation of azo dyes. This paper holds significant importance for the development of novel azo dye wastewater treatment agents. [ABSTRACT FROM AUTHOR]

Two novel metal complexes, C1 and C2, were synthesized through the reaction of an azo dye ligand, obtained by coupling 4‐chloroaniline with 1,3‐dimethyl barbituric acid. The structure of the ligand was confirmed using Fourier‐transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance (NMR). UV–Vis spectroscopy was employed to assess the ligand's sensing ability toward six different metal ions. Comprehensive characterization of the synthesized metal complexes was conducted using elemental analysis, X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis–difference thermogravimetry (TGA‐DTG), FTIR, UV–Vis spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and single‐crystal X‐ray diffraction (SC‐XRD). X‐ray analysis revealed octahedral coordination geometry with a 2:1 ligand‐to‐metal ratio and dimethylformamide (DMF) coordination with the metal atom in both complexes. Hirshfeld analysis and 2D fingerprint plots were employed to investigate supramolecular and intermolecular interactions within the crystal system. Density functional theory (DFT/B3LYP) calculations were utilized to compute energy gaps and other important theoretical features. Sensing experiments with tetrabutylammonium fluoride (TBAF) were conducted at a concentration of 1 × 10−5 M. Furthermore, the bioactivity of the synthesized metal complexes and ligand L was evaluated through molecular docking studies against Protein Data Bank (PDB IDs) 4XUY (Staphylococcus aureus) and 3BQW (Aspergillus niger). Also, antimicrobial activity was assessed using the agar well diffusion technique, revealing that complexes C1 and C2 exhibited enhanced antimicrobial activities against the tested organisms compared to the parent azo dye ligand. The computational and experimental bioactivity data are in good agreement with each other. [ABSTRACT FROM AUTHOR]

Water is the utmost essential commodity for the support of life process in animals. In recent decades, rapid industrialization and uncontrolled agricultural practices have led to increased level of toxic pollutants in groundwater, including organic pollutants (dyes, nitroarene compounds, antibiotics, etc.), inorganic pollutants (heavy metals, nanoparticles, etc.), and pesticides, posing a serious threat to human health and the environment. Although various technologies such as adsorption, photocatalysis, reverse osmosis, filtration, sedimentation, flocculation, and precipitation are available for the elimination of toxic pollutants from wastewater, issues such as their cost and efficacy limit their usage. Recently, catalysis has been found to be the most effective approach since it exhibits significant capability to eliminate almost all the pollutants and offers the benefit of simple design and low initial cost. In the present study, ternary zinc–copper–nickel layered double hydroxide (ZnCuNi‐LDH) synthesized using facile acid hydrolysis method was employed as an efficacious heterogeneous catalyst for the reduction of NACs (para‐nitrophenol and para‐nitroaniline) and degradation of organic azo dyes (methyl orange, amaranth, and brilliant black). ZnCuNi‐LDH exhibited superior catalytic activity for the reduction of all five model pollutants with reduction efficiency of more than 95% within a short time span of 5 min. Therefore, keeping in view the layered structure, high specific surface area, and remarkable catalytic performance, ZnCuNi‐LDH holds immense potential for the large‐scale catalytic degradation of refractory pollutants. [ABSTRACT FROM AUTHOR]

One of the biggest issues affecting the entire world currently is water contamination caused by textile industries' incapacity to properly dispose their wastewater. The presence of toxic textile dyes in the aquatic environment has attracted significant research interest due to their high environmental stability and their negative effects on human health and ecosystems. Therefore, it is crucial to convert the hazardous dyes such as methyl orange (MO) azo dye into environmentally safe products. In this context, we describe the use of Copper Nitroprusside Chitosan (Cu/SNP/Cts) nanocomposite as a nanocatalyst for the chemical reduction of azodyes by sodium borohydride (NaBH4). The Cu/SNP/Cts was readily obtained by chemical coprecipitation in a stoichiometric manner. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) spectroscopy were applied to investigate chemical, phase, composition, and molecular interactions. Additionally, Scanning electron microscope (SEM) was used to examine the nanomaterial's microstructure. UV–vis spectroscopy was utilized for studying the Cu Nitroprusside Chitosan's catalytic activity for the reduction of azodye. The Cu/SNP/Cts nanocomposite demonstrated outstanding performance with total reduction time 160 s and pseudo-first order constant of 0.0188 s−1. Additionally, the stability and reusability study demonstrated exceptional reusability up to 5 cycles with minimal activity loss. The developed Cu/SNP/Cts nanocomposite act as efficient nanocatalysts for the reduction of harmful Methyl orange azodye. [ABSTRACT FROM AUTHOR]

Chitosan, a biopolymer obtained from chitin, is known for its remarkable adsorption abilities for dyes, drugs, and fats, and its diverse array of antibacterial characteristics. This study explores the extraction and characterization of chitosan from the mycelium of Amanita phalloides. The moisture content, ash content, water binding capacity, fat binding capacity, and degree of deacetylation of the extracted chitosan were determined. The chitosan exhibited a high yield of 70%, crystallinity of 49.07%, a degree of deacetylation of 86%, and potent antimicrobial properties against both Gram-negative and Gram-positive bacteria. The study also examined the adsorption capabilities of chitosan to remove methylene blue (MB) dye by analysing specific factors like pH, reaction time, and MB concentration using the response surface model. The highest degree of MB dye removal was 91.6% at a pH of 6, a reaction time of around 60 min and an initial dye concentration of 16 ppm. This experimental design can be applied for chitosan adsorption of other organic compounds such as dyes, proteins, drugs, and fats. [ABSTRACT FROM AUTHOR]

In this study, the efficiency of poly(ethylene glycol dimethacrylate-N-methacryloyl-amido-l-tryptophan methyl ester) [PEDMT] microbeads (in the diameter range of 106–180 µm) as a support material for HRP immobilization was evaluated and the immobilized-HRP enzyme was used for decolorization of Congo Red (CR) and Reactive Black 5 (RB5) dyes. The specific surface area of the PEDMT microbeads was 1103 m2 g−1, which is very high. The PEDMT microbeads had a pore volume and pore size of 1.94 cm3 g−1 and 9.99–55.3 Å, respectively. The chemical compositions of the PEDMT and PEDMT–HRP microbead surfaces were analyzed using X-ray photoelectron spectroscopy (XPS). Immobilization yield, activity yield, and immobilization efficiency were 84.9 ± 2.1, 73.8 ± 5.9%, and 86.9 ± 6.9%, respectively. Optimum pH (6.0), temperature (45 °C and 50 °C for free and immobilized enzyme), H2O2 concentration (3% v/v) were investigated in detail. Thermal and storage stability was increased after immobilization and immobilized enzyme preserved more than 55% of its initial activity even after 10 consecutive uses. Decolorization studies were also performed by investigating the effects of pH, CR, and RB5 concentration, enzyme amount, H2O2 concentration, contact time on decolorization efficiency. The decolorization efficiency for CR and RB5 by PEDMT–HRP was 98.20% and 47.99% after 30 min at pH 6.0 and 45 °C. The immobilized-HRP retained 89% and 27% of its initial activity after three repeated cycles with CR and RB5, respectively. The PEDMT microbeads with high surface area, porosity, durability, and reusability exactly met the requirements for HRP immobilization and dye decolorization. [ABSTRACT FROM AUTHOR]

This work describes a sustainable and efficient methodology for incorporating cuprous oxide nanoparticles into MIL-100(Fe) through functionalization with Cryptolepis buchanani Roem. & Schult extract, giving rise to a nanocomposite referred to as Cu2O@MIL-100(Fe). This composite provides a strategy for antimicrobial treatments and catalytic degradation of azo dye pollutants. The analysis delves into the physiochemical properties of the resulting composite materials, assessing their potential for antibacterial activity against both Gram-negative (Acinetobacter baumannii) and Gram-positive bacteria (Staphylococcus aureus), and their efficacy in catalyzing the decomposition of methyl orange dye. The successful integration of Cu2ONPs into MIL-100(Fe) was confirmed using transmission electron microscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffraction, and Brunauer–Emmett–Teller analysis. Functionalizing MIL-100(Fe) with the extract resulted in an average Cu2ONPs size of 4.28 ± 0.87 nm, exhibiting uniform distribution within the structure of MIL-100(Fe). DFT model calculations reveal the low-spin octahedral-site Fe3+ of MIL-100, which is favorable for binding to the phenolic compounds in the plant extract. Antibacterial activity tests indicated a significant enhancement in antibacterial properties, with minimum inhibitory concentrations of 1.5 and 3 mg mL−1 against Acinetobacter baumannii and Staphylococcus aureus, respectively. The synthesized Cu2O@MIL-100(Fe) exhibited effective catalytic activity in the degradation of methyl orange dye, with a pseudo-first-order rate constant ranging from 0.4237 to 0.5160 min−1, contingent upon the catalyst quantity, achieving complete degradation within 8 min. These findings provide valuable insights into the sustainable, non-toxic, and cost-effective synthesis process for Cu2ONPs, highlighting their potential as catalysts in water purification processes and as antimicrobial components in disinfectant formulations. [ABSTRACT FROM AUTHOR]

This article presents the growth of uniformly distributed nickel oxide (NiO) nanofibers on a glass substrate by the Successive Ionic Layer Adsorption and Reaction (SILAR) process and explores its photocatalytic features towards an AZO dye. The nanofiber grown by the SILAR process is subjected to annealing at 400°C to decompose the hydroxide group into oxide. X-ray diffraction pattern divulges the Face-Centered Cubic (FCC) structure of NiO, and its average crystallite size (46–61 nm). The fibrous morphology with the width varying from 37.83 to 42.05 nm is confirmed through FESEM micrographs. The existence of nickel and oxide, with atomic percentages in the ratio 40:60 is confirmed by EDX analysis. From the UV–visible spectrum, the band gap energy E g is determined using a Tauc plot and the values are varied between 3.38 eV and and 3.41 eV. Photocatalytic degradation efficiency for the Congo red dye is found to be 93% for reusable NiO nanofibers under the illumination of UV light. The photodegradation pathway of Congo red dye is presented based on gas chromatography-mass spectrometry (GC-MS) analysis. The prospective applications of the current work in wastewater treatment make it significant. [ABSTRACT FROM AUTHOR]

Photocatalysis, mainly using TiO2 as a catalyst, has emerged as a promising method to address the issue of wastewater treatment. This study explores the enhanced photocatalytic activity of TiO2 through the introduction of reduced graphene oxide (rGO) and cadmium sulfide (CdS) as selective metal dopants. The incorporation of rGO and CdS into the TiO2 lattice aims to optimize its photocatalytic properties, including bandgap engineering, charge carrier separation, and surface reactivity. The unique combination of CdS and rGO with TiO2 is expected to boost degradation efficiency and reduce the reliance on expensive and potentially harmful sensitizers. This experimental investigation involves the synthesis and characterization of TiO2-based photocatalysts. The photocatalytic degradation of methyl orange (MO) and methylene blue (MB) was assessed under controlled laboratory conditions, studying the influence of metal dopants on degradation kinetics and degradation efficiency. Furthermore, the synthesized photocatalyst is characterized by advanced techniques, including BET, SEM, TEM, XRD, and XPS analyses. The degraded samples were analyzed by UV-Vis spectroscopy. Insights into the photoexcitation and charge transfer processes shed light on the role of metal dopants in enhancing photocatalytic performance. The results demonstrate the potential of a TiO2-rGO-CdS-based photocatalyst in which 100% degradation was achieved within four hours for MO and six hours for MB, confirming efficient azo dye degradation. The findings contribute to understanding the fundamental principles underlying the photocatalytic process and provide valuable guidance for designing and optimizing advanced photocatalytic systems. Ultimately, this research contributes to the development of sustainable and effective technologies for removing azo dyes from various wastewaters, promoting environmental preservation and human well-being. [ABSTRACT FROM AUTHOR]

In this study, ethylene diamine-coated reduced graphene oxide-supported silver composite (Ag/rGO-ED) was synthesized and used as an efficient catalyst for the decolorization of methylene blue (MB) in the presence of NaBH4. The morphology of the obtained material was elucidated using field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. The influences of four parameters (MB concentration (mg/L), NaBH4 amount (mM), catalyst amount (g/L), and contact time (s)) on the decolorization process were appraised and optimized via response surface methodology (RSM). For the decolorization of MB, the optimum solutions were obtained as Co of 32.49 mg/L, NaBH4 amount of 152.89 mM, catalyst amount of 0.83 g/L, and 101.39 s contact time with MB decolorization efficiency of 97.73%. MB, a pollutant in wastewater, was decolorized rapidly by Ag/rGO-ED with an efficiency of approximately 97%. The exploration of kinetics and thermodynamics was another major emphasis of the work. The activation energy (Ea) and rate constant (k) for the decolorization of MB were obtained as 37.9 kJ/mol and 0.0135 s−1, respectively. The obtained results show that the catalyst, a new composite material in the literature, is promising for decolorization of wastewater. [ABSTRACT FROM AUTHOR]

This study focuses on the elimination of residual dyes from industrial wastewater using talc as an adsorbent. Talc is an easily available, ecological, and inexpensive adsorbent. The adsorption process was tested on two model dye samples (Ecozol Blue LR Liquid and Cartasol Yellow 3GF Direct Yellow 132), and two samples of real wastewater from the pulp and paper industry (PM and TP). Kinetic studies revealed that the adsorption of Ecozol Blue LR Liquid followed pseudo-second-order kinetics, while the other tested samples followed pseudo-first-order kinetics. Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherm models were also evaluated. The Langmuir isotherm model best fitted the experimental data for the adsorption of model dye solutions and wastewater sample TP onto talc. For wastewater sample PM, the Dubinin-Radushkevich isotherm model provided the best fit to the experimental data. The results of the adsorption isotherms indicated that the adsorption of all tested systems was favorable and primarily involved physical adsorption. The adsorption efficiency for the model solutions exceeded 90 %. For real wastewater samples, the monitored adsorption efficiency in the COD pollution indicator was less efficient, ranging from 43 to 51 %. The lower efficiency of COD may have resulted from the adsorption of residual dyes with lower specific COD values before the adsorption of other organics.

Abstract One of the biggest issues affecting the entire world currently is water contamination caused by textile industries’ incapacity to properly dispose their wastewater. The presence of toxic textile dyes in the aquatic environment has attracted significant research interest due to their high environmental stability and their negative effects on human health and ecosystems. Therefore, it is crucial to convert the hazardous dyes such as methyl orange (MO) azo dye into environmentally safe products. In this context, we describe the use of Copper Nitroprusside Chitosan (Cu/SNP/Cts) nanocomposite as a nanocatalyst for the chemical reduction of azodyes by sodium borohydride (NaBH4). The Cu/SNP/Cts was readily obtained by chemical coprecipitation in a stoichiometric manner. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) spectroscopy were applied to investigate chemical, phase, composition, and molecular interactions. Additionally, Scanning electron microscope (SEM) was used to examine the nanomaterial's microstructure. UV–vis spectroscopy was utilized for studying the Cu Nitroprusside Chitosan's catalytic activity for the reduction of azodye. The Cu/SNP/Cts nanocomposite demonstrated outstanding performance with total reduction time 160 s and pseudo-first order constant of 0.0188 s−1. Additionally, the stability and reusability study demonstrated exceptional reusability up to 5 cycles with minimal activity loss. The developed Cu/SNP/Cts nanocomposite act as efficient nanocatalysts for the reduction of harmful Methyl orange azodye.