Presence Of Cationic Dyes Research Articles

Strontium-doped chromium oxide for RhB reduction and antibacterial activity with evidence of molecular docking analysis.

The emergence of multi-drug resistance (MDR) in aquatic pathogens and the presence of cationic dyes are the leading causes of water contamination on a global scale. In this context, nanotechnology holds immense promise for utilizing various nanomaterials with catalytic and antibacterial properties. This study aimed to evaluate the catalytic and bactericidal potential of undoped and Sr-doped Cr2O3 nanostructures (NSs) synthesized through the co-precipitation method. In addition, the morphological, optical, and structural properties of the resultant NSs were also examined. The optical bandgap energy of Cr2O3 has been substantially reduced by Sr doping, as confirmed through extracted values from absorption spectra recorded by UV-Vis studies. The field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) micrographs illustrate that the composition of Cr2O3 primarily consisted of agglomerated, irregularly shaped NSs with a morphology resembling nanoflakes. Moreover, the presence of Sr in the lattice of Cr2O3 increased the roughness of the resulting NSs. The catalytic activity of synthesized NSs was analyzed by their reduction ability of Rhodamine B (RhB) dye in the dark under different pH conditions. Their antibacterial activity was evaluated against MDR Escherichia coli (E. coli). Sr doping increased antibacterial efficiency against MDR E. coli, as indicated by inhibition zone measurements of 10.15 and 11.75mm at low and high doses, respectively. Furthermore, a molecular docking analysis was conducted to determine the binding interaction pattern between NSs and active sites in the target cell protein. The findings corroborated antimicrobial test results indicating that Sr-Cr2O3 is the most effective inhibitor of FabH and DHFR enzymes.

Aminated Covalent Organic Polymers for Anionic Dye Adsorption in Aqueous Systems

Aminated covalent organic polymer (ACOP) was synthesized through a catalyst-free Schiff base reaction involving terephthalaldehyde and melamine, and the prepared ACOP was used for the adsorption of anionic dyes. The prepared ACOP possessed a high specific surface area (582.07 m2/g) with an average pore size of 88.71 Å. Its point of zero charge was determined as pH 8.26. Anionic dye molecules, methyl orange (MO) and orange G (OG), were used to evaluate the dye adsorption efficiency of the prepared ACOP, and it was found that they were adsorbed rapidly on ACOP within 1 min. The maximum adsorption capacities (qm) of the prepared ACOP for MO and OG were 351.9 and 227.9 mg/g, respectively. Furthermore, the results of dye adsorption as a function of the initial pH and presence/absence of cationic dye (methylene blue; MB) revealed that dye adsorption on ACOP proceeded through charge–charge and π–π interactions. The presence of MB along with MO and OG enhanced the dye adsorption capacity because of the synergistic effect of the positively charged quaternized nitrogen atoms in the prepared ACOP. The dye adsorption mechanism was further investigated using Fourier transform infrared (FT-IR) analysis and X-ray photoelectron spectrometry (XPS). The ACOP adsorbent prepared herein using a facile catalyst-free reaction offers rapid adsorption with a high adsorption efficiency over a wide pH range and in the presence of cationic dye. For these reasons, it can be used for environmental remediation, especially in aqueous systems.

Lignin from Agro-Industrial Waste to an Efficient Magnetic Adsorbent for Hazardous Crystal Violet Removal.

The presence of cationic dyes, even in a tiny amount, is harmful to aquatic life and pollutes the environment. Therefore, it is essential to remove these hazardous dyes to protect the life of marine creatures from these pollutants. In this research, crystal violet (CV) dye elimination was performed using a lignin copper ferrite (LCF) adsorbent. The adsorbent was synthesized and characterized using FTIR, Raman, SEM, EDX with mapping, and VSM, which proved the successful formation of magnetic LCF. Adsorption experiments were performed using different effective parameters. The highest adsorption potential (97%) was executed at mild operating conditions, with a 5 min contact time at room temperature and pH 8. The adsorption kinetic study utilized four kinetic models: first-order, second-order, intraparticle diffusion, and Elovich. The results revealed that the adsorption process complies with the pseudo-first-order with a maximum adsorption capacity of 34.129 mg/g, proving that the adsorption process mechanism is a physical adsorption process. Three isotherm models, Langmuir, Freundlich, and Temkin, were examined. The adsorption mechanism of CV onto LCF was also followed by the Langmuir and Freundlich models. The thermodynamic parameters were examined and revealed that the adsorption onto LCF was an exothermic process. It was proposed that the adsorption process is a spontaneous exothermic process. LCF appears to forcefully remove toxic CV dye from textile wastewater.

Preparation of pyridine-modified cotton fibers for anionic dye treatment

In order to prepare low-cost, biodegradable and processable adsorbent materials, and also provide a new solution for textile dyeing, novel modified cottons were obtained by introducing 4-aminopyridin into the surface of cotton fibers, and used for the removal of the anionic dyes from aqueous solution. The two modified cottons were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), which confirmed the amino groups and pyridine groups grafted onto the surface of modified cottons. The maximum adsorption capacities for congo red, methyl orange and orange II were 984.87 mg/g (pH = 12), 489.8 mg/g (pH = 8.5) and 599.66 mg/g (pH = 8), respectively. Kinetic and isotherm studies were carried out to investigate the adsorption behavior of the modified cottons on the anionic dyes. The results showed that the adsorption of the anionic dyes by modified cottons followed a pseudo-second-order kinetic model, the equilibrium data was well consistent with the Langmuir isotherm model, and chemisorption and monolayer adsorption were the main adsorption mechanisms. The reuse efficiency of modified cotton was over 80% after six cycles. In addition, the presence of cationic dyes has almost no effect on the adsorption of anionic dyes, and the modified cotton exhibited highly selective adsorption of methyl orange in mixed solutions of methyl orange and methylene blue. This paper also provided a new solution for textile dyeing.

The Effectiveness of <i>Scolymus Maculatus</i> in the Removal of Basic Blue Dye 41 in Aqueous Solutions: Kinetics and Thermodynamics

The presence of cationic dyes; especially the basic ones in an aqueous solution causes several problems. Therefore, it is necessary to reduce itfrom industrial effluents before being discharged into the environment. This study aimed to investigate the removal of Basic Blue 41 (BB41) dye from an aqueous solution using agricultural waste as an adsorbent. This study was conducted in a batch experimental system. The effect of various parameters such as initial dye concentration, pH, pH_zpc and adsorbent dosage was studied. The data were examined by Freundlich, Temkin, Debinin-Radushkevich, pseudo first order and pseudo second order kinetic, and thermodynamic parameters. The characterization of the adsorbent was determined by the Scanning Electron Microscopy (SEM), Fourier transform infrared (FTIR) and X-Ray Diffraction (DRX). The results of this work showed that the <i>Scolymus Maculatus</i> adsorbent was proven most effective in removing Basic Blue 41 from an aqueous solution at pH=7,09 with 85,14%. The results showed also that the adsorption process follows the Freundlich isotherm as well as pseudo-second-order kinetic. The results of the thermodynamic process showed that the adsorption is spontaneous and endothermic in nature.

Synergetic effect of adsorption-photocatalysis by [formula omitted]nanocomposites for photodegradation of doxorubicin

The photodegradation of DOX is investigated by adsorption-photocatalysis synergy. Graphene oxide - cerium oxide (GO−CeO2) nanocomposites have been synthesized and their structural, optical, and morphological properties are investigated. The synthesized GO−CeO2nanocomposites are highly crystalline and exhibit lower optical bandgap energy of 3.2 eV, a narrow particle size distribution of 7–11 nm. The UV–Vis spectroscopy data suggests that 97% of DOX is removed within 360 min by the adsorption-photocatalysis synergy. The pH of the DOX solution widely affected the removal process; neutral and alkaline conditions of pH supported the degradation process. GO−CeO2 nanocomposites exhibited preferable performance stability and retained the removal efficiency even after the fifth cycle of removal. The enhanced photocatalytic activity of the GO−CeO2is attributed to the lower bandgap energy and interfacial charge transfer at the heterojunction of GO matrix and anchored CeO2nanoparticles. Furthermore, the degradation of DOX in presence of co-existing ions and organic dyes was also studied. The influence of coexisting ions showed higher order of removal efficiency for monovalent ions as compare to divalent ions. Similarly, within the presence of cationic dye, the removal process of DOX was found prominent. The high-performance liquid chromatography (HPLC) analysis confirmed 99.8% removal efficiency in 420 min which indicates complete eradication of DOX without any secondary pollution. Hence, the GO−CeO2a photocatalytic adsorbent with higher stability and recyclability would provide a cost-effective and eco-friendly approach for the mitigation of DOX without any secondary toxic metabolites.

CMC studies of CTAB, SLS & tween 80 by spectral and conductivity methodology to explore its potential in photogalvanic cell

In the present article, the critical micelle concentration (CMC) of cetyltrimethylammonium bromide (CTAB, cationic), sodium lauryl sulphate (SLS, anionic) and tween 80 (nonionic) surfactants has been studied in the presence and absence of methylene blue (MB) dye via spectral and conductometric studies. The magnitude of CMC value of SLS was decreased in large amount in presence of MB due to the cationic and anionic (electrostatic) interaction, while a little bit decrement was obtained with tween 80 and no remarkable change was obtained with CTAB. Since, both the observed values with conductometric and spectral studies supports each other and also founds that the CMC value of SLS and CTAB with MB dye was almost similar to the reported resultant concentration of SLS and CTAB at which the maximum electrical out put was obtained for diffrent dye-reductant-surfactant systems in photogalvanic cells. Therefore, the surfactant (SLS) whose CMC value is more affected in the presence of cationic dye (MB) may be more useful in the photogalvanic cell with suitable reductant. Hence, with this study, the micellar concentration of surfactants can evaluate and dye-surfactant combination in which CMC of surfactant is more affected in presence of dye can be utilized to enhance the overall electrical performance of the photogalvanic cells.

Cationic dyes as morphology-guiding agents for one-dimensional polypyrrole with improved conductivity

Polypyrrole was prepared in the presence of cationic dyes, safranin and phenosafranin. The safranin supported the one-dimensional growth of polypyrrole, converting globules to nanorods and later also to nanotubes, particularly at higher dye concentrations. In the case of phenosafranin, the produced nanotubes were considerably thicker and were always accompanied by globules. Upon oxidation both dyes are expected to generate insoluble oligomeric templates that serve as loci for the deposition of polypyrrole. The formation of globular morphology takes place when the dye becomes depleted, due to its low concentration for safranin, or because of robust templates produced by phenosafranin. In addition to scanning and transmission electron microscopies, the resultant polypyrroles were characterized by FTIR and Raman spectroscopies, and DC conductivity measurements. The conversion of globular morphology to nanotubes/nanofibers was accompanied by the increase in conductivity from 5 to 35 S cm−1, which was explained by the improved ordering of polypyrrole chains more preferable for charge transport. The series of syntheses at varying oxidant-to-pyrrole mole ratios confirmed the stoichiometric ratio 2.5 to be the best for pyrrole oxidation but a good stability of polypyrrole was demonstrated even at extremely high stoichiometric ratio 15.

Rapid adsorption of ternary dye pollutants onto copper (I) oxide nanoparticle loaded on activated carbon: Experimental optimization via response surface methodology

Rapid adsorption of hazardous anionic dyes sunset yellow (SY), eosin B (EB) in the presence of cationic dye i.e. methylene blue (MB) from ternary solutions using copper oxide nanoparticle loaded on activated carbon(Cu2 O-NP-AC) was well investigated and elucidated. The synthesized adsorbent was well characterized using various analytical techniques such as X-ray diffraction (XRD), and FE-SEM. The impact of effective parameters such as pH, sonication time, adsorbent dosage and initial dye concentration was well studied and optimized using central composite design superimposed with response surface methodology. The numerical optimization revealed that the optimum removal (>96.0%) for all dyes were achieved using of 0.025g, 25, 15and15mgL−1 of SY, EB and MB after 4min sonication at pH of 5.0at above conditions. The adsorption equilibirium and kinetic data was well fitted and found to be in good agreement with Langmuir and pseudo-second order respectively. The maximum adsorption capacities SY, EB and MB were 113, 137 and 110mgg−1, respectively.

Mechanistic study of cationic dye interactions with clay‐polymer dispersions via metachromatic effect, aggregation, and surface charge

ABSTRACTInteractions for a series of aqueous dispersions of a clay, Laponite, and nonionic difunctional triblock copolymer, Pluronic L62, with two cationic dyes, crystal violet and brilliant green, are studied using UV–vis spectroscopy, dynamic light scattering (DLS), and electrophoretic mobility (EPM) to better understand the adsorption mechanisms. Different concentrations for clay, 0.1–2.0 g/L, mixed with polymer, 0.125–0.5 g/L to produce an organoclay, were tested with a fixed dye concentration, 2.0 × 10−5 mol/L. The aggregation states of the cationic dyes interacting with the clay–polymer dispersions were characterized by UV–vis absorbance. The dyes changed aggregation states from monomer to dimer and higher aggregate states upon addition to varying Laponite–polymer dispersion concentrations. DLS was used to understand the adsorbed polymer and dye interactions on the clay particle showing longer relaxation times for the largest aggregates observed from UV–vis absorbance. The EPM was used to characterize the surface charge of the clay relative to the polymer–dye interactions, which showed that the surface charge approached zero as the dyes interacted with clay–polymer dispersions. The most significant changes occurred with a reduction in light scattering intensity and longer relaxation decay at 0.1 g/L Laponite and 0.5 g/L Pluronic L62 concentrations in the presence of cationic dyes. The study of the clay–polymer–dye interactions help to better understand and design chemical templates for removal of contaminates in waste‐water treatment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40141.

Improved chondrocyte morphology and glycogen retention in the secondary center of ossification following osmium‐potassium ferrocyanide fixation

The use of osmium-potassium ferrocyanide as the secondary fixative greatly improved chondrocyte preservation and stabilized the cartilage matrix proteoglycan. The proteoglycan was similar in appearance to that seen following fixation in the presence of cationic dyes. Extensive glycogen preservation was noted in these cells, occupying the area prior to and during the formation of the secondary center of ossification. The volume and organization of the glycogen within the cell cytoplasm were greater than that following buffered osmium fixation, and the cellular vacuoles within were greatly reduced. The cells forming the secondary center prior to the onset of mineralization were of greatest interest, because other studies compared them with the primary growth plate and described them as showing signs of hypertrophy as early as 5 days postnatally, as is found in the primary growth plate. Our observations indicate that glycogen is present in these cells, and cellular enlargement was not present. The cells do not resemble the hypertrophic chondrocytes of the primary growth plate, as far as cytoplasmic content is concerned, and we suggest that they may contribute to the development of the secondary center in a different fashion.

Grafting of polypropylene fibers. II. Electrokinetic properties of grafted polypropylene fibers

Electrokinetic properties of methacrylic acid- and acrylonitrile-grafted polypropylene fibers measured in the presence of cationic dyes are reported. The zeta potential of polypropylene fibers decreases, and the surface charge density along with surface conductivity increases as the concentration of the dyes in the streaming solution increases. The zeta potential at pH 7 decreases as the amount of graft increases in case of both acrylonitrile- and methacrylic acid grafted fibers. Both surface charge density and surface conductivity increase with the increase in dye concentration for both acrylonitrile- and methacrylic acid-grafted fibers. The results are explained on the basis of the cationic dye adsorption on the grafted fiber in the case of methacrylic acid graft. In the case of acrylonitrile-grafted fibers, this could be due to the strong attraction of cationic dye to the nitrile group of the grafted fibers.

Ultrastructure and staining properties of aortic microfibrils (oxytalan).

Microfibrils are the insoluble, 10- to 12-nm components of the extracellular matrix that are involved in elastogenesis. Reports of their ultrastructure vary: they have been described as tubular and beaded and as nontubular filaments that are devoid of any periodicity. Ultrastructurally, microfibrils resemble oxytalan fibers that have been observed in peridontal membranes, skin, and other locations. Whether microfibrils have the staining characteristics of oxytalan is difficult to determine in tissues because available light microscopic stains also stain elastin. Calf aortic smooth muscle cells grown in media without added ascorbate provide a unique model for examining the ultrastructure and staining characteristics of chemically defined microfibrils. Microfibrils are the predominant insoluble extracellular protein in such cultures, which do not deposit collagen or elastin. These studies demonstrate that microfibrils are tubular structures with 10- and 12-nm striations and have the same staining characteristics as oxytalan, reacting with aldehyde fuchsin and orcein after oxidation. Microfibrillar protein is enriched in glutamic and aspartic acids and the electron density of microfibrils is enhanced by fixation in the presence of cationic dyes. In such preparation, microfibrils are made visible within the core of amorphous elastin as well as in regions that are free of elastin. The widespread distribution of microfibrils (oxytalan) indicates that their function extends beyond elastogenesis. Their localization within tissues suggests that they serve as an elastic attachment protein in sites that are subject to mechanical stress.

Method for the Assessment of the Dyeing Conditions of Modified Polyester with Cationic Dyes

A study of the dyeing behaviour of modified polyester fibre in the presence of cationic dyes has been carried out. The initial and final dyeing temperatures and the rate of heating of the dyebath for different initial concentrations of dye have been calculated from the results of isothermal dyeings at different temperatures and the Arrhenius equation. The equivalent concentrations of the dyes tested, i.e. concentrations producing the same exhaustion curve, have been determined. The initial and final temperatures of the process for any given rate of dyeing have been calculated.

Grafting onto polyester fibers. III. Electrokinetic properties of acrylic acid and acrylonitrile‐grafted polyester fibers in the presence of cationic dyes

AbstractThe electrokinetic properties such as zeta potential, surface charge density, and surface conductivity of polyester fibers grafted with acrylic acid and acrylonitrile were measured when cationic dye solutions were streamed through. The presence of the cationic dyes on the surface of the fibers and their specific adsorption at the carboxylic groups in the acrylic acid graft copolymer produce lowering of zeta potential. The decrease in surface charge density as the percent graft increases is due to the decrease in surface area of the fibers due to the adsorption of the cationic dyes. The same trend is observed with acrylonitrile‐grafted fibers. The surface conductivity of the acrylonitrile‐grafted polyester fibers increases with increase in dye concentration of the streaming solution. The results for the 27.4% grafted sample differed from those of the 7.32% and 12.1% grafts, which is indicative of the formation of a three‐dimensional network causing change in both the physical structure as well as the chemical nature of the surface of the substrate.