Triphenylmethane Dyes Research Articles

Comprehensive insights into the binding of crystal violet and pepsin: Spectroscopic analysis, molecular model and biochemical method

As a well-known triphenylmethane dye, crystal violet (CV) has received extensive concerns owing to its harmful influence on human health. Pepsin is a digestive enzyme in the stomach that plays a crucial part in several physiological and pathological process. This research aimed to use spectroscopic experiments, computer simulation and enzyme activity assays to investigate the influence of CV on the functions and structure of pepsin from the perspective of binding. Fluorescence and UV–vis spectra confirmed the complex formation between CV and pepsin. Ka was in the order of 104 M−1, implying a moderate affinity between CV and pepsin. Multi non-covalent interactions played a crucial part in this binding process. The conformational alterations of pepsin caused by CV were reflected in β-sheet content reducing, and the presence of CV caused an activation of pepsin. The outcomes of molecular docking indicated that the interaction of Tyr75/Tyr189 with CV is the major cause for the fluorescence quenching phenomenon of pepsin. For molecular dynamics (MD) simulation, the CV-pepsin and free pepsin systems reached equilibrium in 40 ns. In addition, the compactness of pepsin changed after interacting with CV, which was in line with the results of solvent experiment. From the above results, CV has effects on the properties of pepsin, which may provide novel insights into the toxicological study of CV.

DNA major versus minor groove occupancy of monomeric and dimeric crystal violet derivatives. Toward structural correlations

Six monomeric (1a-1f) and five dimeric (2a-2e) derivatives of the triphenylmethane dye crystal violet (CV) have been prepared. Evaluation of the binding of these compounds to CT DNA by competitive fluorescent intercalator displacement (FID) assays, viscosity experiments, and UV and CD spectroscopy suggest that monomeric derivative 1a and dimeric derivative 2d likely associate with the major groove of DNA, while dimeric derivatives 2a and 2e likely associate with the minor groove of DNA. Additional evidence for the groove occupancy assignments of these derivatives was obtained from ITC experiments and from differential inhibition of DNA cleavage by the major groove binding restriction enzyme BamHI, as revealed by agarose gel electrophoresis. The data indicate that major groove ligands may be optimally constructed from dye units containing a sterically bulky 3,5-dimethyl-N,N-dimethylaniline group; furthermore, the groove-selectivity of olefin-tethered dimer 2d suggests that stereoelectronic interactions (n → π*) between the ligand and DNA are also an important design consideration in the crafting of major-groove binding ligands.

Catalytic Degradation of Triphenylmethane Dyes with an Iron Porphyrin Complex as a Cytochrome P450 Model.

The organic dyes used in printing and dyeing wastewater have complex components, diverse structures and strong chemical stability, which make them not suitable for treatment and difficult to degrade in the environment. Porphyrins are macromolecules with 18 π electrons formed by four pyrrole molecules connected with a methylene bridge that has a stable structure. Porphyrin combines with iron to form an active intermediate with a structure similar to the cytochrome P450 enzyme, so they are widely used in the biomimetic field. In the current study, 5,10,15,20-tetra (4-carboxyphenyl) porphine ferric chloride (III) (Fe(III)TCPP) was used as a catalyst and iodosobenzene was used as an oxidant to explore the catalytic degradation of triphenylmethane dyes, such as rhodamine B (RhB) and malachite green (MG). The results of UV-Vis spectral analysis have shown that the conversion rate of the rhodamine B was over 90% when the amount of Fe(III)TCPP was 0.027 mM and the amount of iodosobenzene was eight equivalents. When the catalyst was 0.00681 mM and the amount of the oxidant was five equivalents, the conversion rate of the malachite green reached over 95%. This work provides a feasible method for the degradation of triphenylmethane dyes.

Mechanistic study on the synergy of cold plasma and sulfate radical in the degradation of azo and triarylmethane dyes using density functional theory

The activation of persulfate using cold plasma and the synergy of plasma-generated reactive species and SO4•− in mineralization of organic dyes were assessed. In this regard, solutions of crystal violet (CV) as a triarylmethane dye and methyl orange (MO) as an azo dye, were treated with cold plasma, UV-C-activated sulfate radicals, and their combination. The achieved results showed 95% TOC removal, a synergy factor of 1.3 and an energy yield of 1.68 (g kWh−1) for the combined system. The contribution of oxidant species in CV (SO4•− > O2•- > •OH) and MO (SO4•−> O2•- >1O2) degradation was explored. Moreover, analysis of degradation products and density functional theory (DFT) calculations were adopted to find the degradation mechanism based on the minimum energy pathway. Experimental and DFT results revealed that while radical and nucleophilic pathways were the drivers of CV degradation, the electrophilic attack of oxidants was a more plausible mechanism for MO degradation. Additionally, a comparison of the results of different DFT methods with experimental values showed that the Kohn–Sham DFT yielded more accurate results compared to recommended double hybrid methods. Analysis of a treated real wastewater revealed that the background constituents had negligible effects on MO and CV degradation. The high TOC removal efficiency of the combined system suggests its feasibility for treating wastewater from fertilizer and pharmaceutical production facilities.

Comparative Advanced Oxidation Decolorization of the Triphenylmethane Dye with Dimethyl Dioxirane and Hydrogen Peroxide

Methyl Violet (MV), a triphenylmethane dye, has been subjected to comparative studies with hydrogen peroxide and dimethyl dioxirane under optimum situations. When employing hydrogen peroxide, the photolysis process becomes slower, but the dye solutions are entirely decolored and mineralized. The decolorization rate exhibits pseudo-first-order kinetics. The effect of pH, oxidant dosage, and methyl violet concentration on the degradation is also examined. Generated o-leucoaniline,1,3-diphenylurea,2-hydroxy benzoic acid, phenol, acetone, water, carbon dioxide, and carbon monoxide are identified and measured by GC-MS analysis. These substances remain in the dye solution along with dimethyl dioxirane, which is released faster during the last stages of degradation. The degradation rates of methyl violet reached 97.9% and 65.8% within 30 mins and 180 min of reaction time using dimethyl dioxirane and hydrogen peroxide.

Biosorption of Triphenyl Methane Dyes (Malachite Green and Crystal Violet) from Aqueous Media by Alfa (Stipa tenacissima L.) Leaf Powder.

This study includes the characterization and exploitation of an abundant agricultural waste in Algeria, Alfa (Stipa tenacissima L.) leaf powder (ALP) as a biosorbent for the removal of hazardous triphenylmethane dyes, malachite green (basic green 4) and crystal violet (basic violet 3), from aqueous media under various operating conditions in batch mode. The effect of experimental parameters such as initial dye concentration (10-40 mg/L), contact time (0-300 min), biosorbent dose (2.5-5.5 g/L), initial pH (2-8), temperature (298-328 K), and ionic strength on dye sorption was investigated. The results of both dyes show that the increase in initial concentration, contact time, temperature, and initial pH of solution leads to an increase in biosorbed quantity, unlike the effect of ionic strength. The biosorption kinetics for triphenylmethane dyes on ALP was analyzed by pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models proposed by the Weber-Morris equation. Equilibrium sorption data were analyzed by six isotherms, namely the Langmuir, Freundlich, Harkins-Jura, Flory-Huggins, Elovich, and Kiselev isotherms. The thermodynamic parameters were evaluated for both dyes. The thermodynamic results suggest that both dyes' biosorption is a typical physical process, spontaneous and endothermic in nature.

One pot synthesis of crystalline covalent organic polymers with tunable pores for the removal of gold and toxic organic pollutants

The construction of crystalline covalent organic framework from flexible building blocks, especially macrocyclic hosts, rare in literature. Further, tuning the number of pores and their sizes in the final covalent organic frameworks (COFs)/covalent organic polymers (COPs) is challenging and exciting. Recently, attempts have been made to synthesise the crystalline covalent organic framework starting from a macrocyclic crown ether host. However, the synthetic strategies involve multi-step organic reactions. Herein, we report the construction of a crystalline covalent organic framework/polymers from a single-step reaction. Further, this approach will allow us to pre-determine the pore sizes and their properties to attain the focused covalent organic frameworks (COFs)/covalent organic polymers (COPs) materials of specific surfaces and functions. Based on this approach, we have constructed two triphenylene-based crown ether COPs, COP-TPC6 and COP-TPC8, from dibenzo-18-crown-6 and dibenzo-24-crown-8, respectively. The obtained COPs displayed remarkable removal capacity toward gold (COP-TPC6 = 1157 mg/g and COP-TPC8 = 943 mg/g) with high selectivity over a wide pH range. Furthermore, the obtained COP-TPCs displayed good removal capacity towards a wide range of organic dyes like thiazine dye, triarylmethane dye and azo dye via supramolecular non-covalent interaction. COP-TPC6 displayed good removal capacity toward Neutral red (NR) (Qmax = 500 mg/g), Malachite green (MG) (Qmax = 364 mg/g) and Mordant orange (MoO) (Qmax = 193.8 mg/g). Similarly, COP-TPC8 displayed a removal capacity of Qmax of 307 mg/g for NR, 544 mg/g for MoO and 144.77 mg/g for MG. This work will help the scientific communities to fabricate adsorbents with combined physical and chemical features of triphenylene and crown ethers units.

Photocatalytic Degradation of Organic Dyes from Clinical Laboratory Wastewater

Clinical laboratory wastewaters are of important environmental concern due to the highly complex chemical reagents and dyes used to identify various pathologies, which are difficult to degrade by conventional treatment methods. The present research aimed to assess the effects of ilmenite use in the discoloration process of clinical laboratory wastewater. The wastewater originates from a Gram staining process used to identify pathogenic microorganisms present in biological samples. The active ingredient is crystal violet, a triphenylmethane dye derivative, highly toxic and non-biodegradable that causes a shiny purple color in the wastewater. The ilmenite was characterized by X-ray Fluorescence, X-ray Diffraction, Scanning Electron Microscopy, energy-dispersive spectroscopy and Nitrogen adsorption isotherm, while the discoloration process of the wastewater was measured by UV–Vis spectrophotometry and pH change trough the reaction time, evaluating different ilmenite loads, particle size and stability under light sources with different energies. Chemical oxygen demand analysis confirmed that acid formation and discoloration were associated with organic substance mineralization. Type C ultraviolet light and 0.7 g/L load were identified as the best operating conditions for the discoloration process. It was possible to establish that ilmenite is stable after four uses in the discoloration process, obtaining, in all cases, discoloration percentages higher than 90% after 3 h of irradiation.

Simple adsorptive removal of crystal violet, a triarylmethane dye, from synthetic wastewater using Fe (III)-treated pine needle biochar.

Untreated and Fe (III)-treated pine needle biochar (PNB) were evaluated at different pH for the removal of toxic crystal violet (CV) dye from synthetic wastewaters. Adsorption kinetics followed the pseudo-first-order kinetics involving intra-particle diffusion process. The adsorption rate constant increased with Fe treatment of PNB especially at pH 7.0. Adsorption data of CV conformed well to Freundlich adsorption isotherms and both adsorption capacity (ln K) and order of adsorption (1/n) of CV were nearly doubled with Fe (III) treatment of PNB at pH 7.0. Desorption of adsorbed CV from both untreated and Fe (III)-treated PNB could be accounted satisfactorily by third-degree polynomial equations. An increase in ionic strength and temperature enhanced dye adsorption onto untreated and Fe (III)-treated PNB. Adsorption of CV was an endothermic and spontaneous reaction with an increase in entropy of the system. FTIR spectra revealed that C = O of carboxylic acid aryls and C = O and C-O-C in lignin residues of PNB reacted with Fe (III) besides the formation of some iron oxyhydroxide minerals. The changes in FTIR confirmed the possible bonding of positively charged moiety of CV with the untreated and Fe-treated PNB. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) revealed the porous surfaces of PNB with clear accumulation of Fe (III) after treatment and deposition of CV dye on surfaces and pores of PNB. Iron (III)-treated PNB at pH 7.0 can serve as an ecofriendly and cost-effective adsorbent for the efficient removal of CV dye from wastewaters.

Degradation of the Chromophore Functions of Dyes in Irradiated Solutions

Radiolysis damages the system of conjugated bonds and thus leads to the degradation of the chromophore functions of dyes in aqueous solutions. Ten representatives of quinophthalone, indigo, triphenylmethane, and azo dyes exhibited the same type of correlations between the absorbed dose and the degree of discoloration. It was shown using the method of competing scavengers that the color of aerated solutions decreased mainly due to the addition of OH radicals to the dyes. The radiation-chemical yields of discoloration ranged from 0.03 to 0.11 μmol/J and increased depending on the length of bond conjugation in the dye molecules. For practical electron-beam discoloration of dye solutions with a concentration of 20 mg/dm3, anabsorbed dose of 1–1.5 kGy was sufficient.

Decolorization of Dyes in the Bioelectrochemical System Depending on the Immobilization of <i>Shewanella oneidensis</i> MR-1 Cells on the Anode Surface and Electrical Stimulation of the External Circuit

The effect of the polarity of the electrical stimulation of the external circuit of the bioelectrochemical systems, as well as the immobilization of Shewanella oneidensis MR-1 cells containing the DyP peroxidase gene on the rate of discoloration of dyes of different types was found. For the crystal violet triphenylmethane dye, the maximum decolorization rate by suspended S. oneidensis MR-1 cells 2.05 ± 0.07 μM/h was noted in the case of connecting a 1.2 V direct polarity DC voltage source. One of the minimum rates was observed in the case of reverse polarity of the connection. In the case of cells immobilized on the anode, the rate was higher, reaching 2.91 ± 0.09 μM/h and did not decrease with increasing substrate concentration. The lowest values were also noted for the reverse connection of the voltage source. In case of the azo dye congo red, the maximum rate was found for a source with direct connection and an open circuit (0.26 ± 0.01 and 0.29 ± ± 0.02 μM/h, respectively), the minimum value is 0.11 ± 0.02 μM/h for reverse connection. For the crystal violet decolorization products, a significant decrease in the intensity of the main absorption peak at 590 nm band was found, with no notable hypsochromic shift. The qualitative changes in the decolorization products composition are indicated by the appearance, in case of a direct polarity of the ionistor connection, of a new absorption maximum in the region of 360 nm. The results may be of interest for the development of new methods of bioelectrochemical cleaning.

Biosynthesis of multifunctional Fe3O4/cocoa pod carbon composite and its versatile role as sonoadsorbent in triphenylmethane textile dye remediation and potential cathode material for energy storage applications

Iron oxide embedded cocoa pod carbon (C@Fe3O4) composite was tailored effectively by the green synthetic route. The multi-functionality of the synthesised nanocomposite was evaluated through its potential suitability for environmental amelioration and energy storage applications. The synthesised composite was characterised by employing various analytical techniques, and the electrochemical aspects were investigated using galvanostatic charge–discharge and cyclic-voltammetry techniques. The magnetic carbon composite exhibits excellent amelioration of triphenylmethane dye from the aquatic matrix. The maximum adsorption capacity of the crystal violet achieved was 804.9 mg/g, following the Langmuir isotherm model and fitting pseudo second-order kinetics. Furthermore, the composite was evaluated for energy storage applications and demonstrated excellent specific capacity of 30.04 mAh/g with outstanding retention of 87.71 %, rendering it a possible cathode choice for potential sustainable energy storage systems.

Ultrasound assisted synthesis of Fe‐TiO2 and Ce‐TiO2 catalysts and subsequent application for photocatalytic, sonocatalytic, and sonophotocatalytic decolorization of basic Victoria blue dye

AbstractSynthesis of Fe‐TiO2 and Ce‐TiO2 catalysts using conventional, and ultrasound assisted (US) homogeneous coprecipitation method has been investigated. Effects of ultrasonic irradiation time and ultrasonic power on catalyst synthesis were studied and it was elucidated that best conditions were 140 W and 60 min, respectively. Characterization using FE‐SEM revealed spherical particles with the size range from 36.4 to 49.4 nm whereas XRD analysis affirmed a mixture of anatase, rutile, and brookite TiO2 phase with crystallite size ranging from 4.18 to 12.99 nm. BET analysis revealed highest specific surface area (211.59 m2/g) for the sonochemically synthesized Ce‐TiO2. The process intensification benefits demonstrated in catalyst synthesis were better crystallinity, lower particle size, and higher surface area. The application of catalyst efficacy was tested for photocatalytic, sonocatalytic, and sonophotocatalytic oxidation where maximum decolorization as 71.97% was obtained for sonochemically synthesized Ce‐TiO2 applied in the sonophotocatalytic approach. Studies related to regeneration, stability, and leaching of Ce and Ti ion from the sonochemically synthesized Ce‐TiO2 catalyst were also performed. It was observed that the catalyst can be regenerated easily and there were no structural changes in the catalyst after regeneration with negligible leaching of the ions from the catalyst into the solution. Overall, an improved process for catalyst synthesis with intensified decolorization application was demonstrated based on the use of ultrasound.

A Histogram-Based Technique for Simultaneous Colorimetric Determination of Malachite Green and Brilliant Green Using Triton X-100 Micelle.

Malachite green (MG) and brilliant green (BG) are two synthetic triphenylmethane dyes with applications in the textile and aquaculture industries. They are considered to be environmental contaminants due to their carcinogenic and mutagenic properties. Both dyes have the same bluish-green color in aqueous solutions. The aim of this study is to develop a colorimetric analysis as a very simple and cost-effective method to determine the residues of MG and BG simultaneously in aqueous industrial samples. This method is based on the alterations in red, blue, green (RGB) color histograms of the dyes in the presence and absence of Triton X-100 micelle. The images of the samples were taken by a digital camera and converted to the RGB color system using MATLAB software. Partial least-squares regression as a powerful chemometrics tool was used for multivariate calibrations and quantitative measurements. The performance of the proposed method was compared with a simple spectrophotometric method as a reference. Relative errors of prediction for colorimetric and spectrophotometric analysis, respectively, in micellar media were 6.56 and 4.61% for MG and 6.38 and 5.24% for BG. The shortest linear ranges for colorimetric and spectrophotometric analysis, respectively, in micellar media were 0.1-10 and 0.5-5 mg/L for MG and 0.1-15 and 0.5-6 mg/L for BG. The recovery percentages obtained from the analysis of the dyes in real samples of fish-pond water and textile wastewater ranged between 91 and 107%. The good correlation between the results of the colorimetric analysis and the spectrophotometric analysis indicates the reliability of the proposed colorimetric method. Also, the results of the relative recovery study showed insignificant matrix effect. This study demonstrates the ability of the colorimetric analysis coupled with chemometrics tools for simultaneous determination of the analytes even with nearly identical colors.

A systematic study of SERS spectra of cationic Raman dyes adsorbed on citrate-stabilized silver nanoparticles

The adsorption (kinetics and signal stability) of cationic triarylmethane dyes and an acridine derivative with various counter-ions on citrate-stabilized hydroxylamine-reduced silver sols was studied using SERS spectroscopy. The influence of the method of nanoparticle synthesis, as well as the composition and ionic strength of the medium on the stability of nanoparticle–dye complexes was investigated.

Efficient degradation and decolorization of triphenylmethane dyes by Serratia sp. WKD under extreme environmental conditions and the mechanism

Microbial degradation of dyes is fundamental and essential for understanding their environmental fate. In this study, a new bacterial strain with efficient degrading capability of triphenylmethane (TPM) dyes named WKD was isolated and identified as the genus Serratia sp. by 16S rDNA analysis. The decolorization of TPM dyes by the strain especially under extreme environmental conditions were studied. The results showed that the strain could completely decolorize Malachite Green (MG) and Crystal Violet (CV) at pH values ranging from 3.0 to 10.0 and at temperatures ranging from 20 °C to 45 °C in a 12 h of incubation. The strain still showed an excellent decolorizing capability even at low (5 °C) and high (60 °C) temperatures. Moreover, the enzymatic analysis indicated that MnP, NADH-DCIP reductase, MG reductase, and CV reductase might be involved in TPM dyes biodegradation. Besides, the biodegradation pathways were proposed based on UV–visible, FTIR, and LC-Q-TOF-MS analyses. Results indicated that degradation of MG by the strain was mainly regulated by N-demethylation and hydroxylation pathways, while degradation of CV was only by the N-demethylation pathway. Therefore, Serratia sp. strain WKD is expected to have a broad application prospect for the bioremediation of TPM dyes, especially in extreme environments.

Enhanced Removal of Organic Dyes Using Co-Catalytic Ag-Modified ZnO and TiO2 Sol-Gel Photocatalysts

Zinc oxide and titanium dioxide semiconductor photocatalysts have been widely utilized in the last few decades for water treatment because of their high photocatalytic efficiency. Recently, a lot of researchers have focused on the improvement of the photocatalytic properties of catalysts through modifying and co-modifying them with different metals and nonmetals. These co-catalytic ions improve the photocatalytic activity of ZnO and TiO2 by reducing its energy band gap. This might be useful in wastewater treatment for the photocatalytic degradation of organic contaminants. In this study, we prepared semiconductor films that were surface-modified with Ag co-catalyst layers via the photo-fixation of Ag (I) ions with varied concentrations (10−2–10−4 M) in the water phase under UV illumination for the first time. The photocatalytic behavior was evaluated by the degradation of malachite green and methylene blue under UV and visible light irradiation. The ZnO/Ag and TiO2/Ag samples showed a faster degradation of malachite green compared to methylene blue due to the formation of stable intermediates by the reaction of OH radicals with the triarylmethane dye (C=C bond) during the photocatalysis. The co-catalytic-silver-modified films had a higher photocatalytic efficiency in comparison with the pure nanostructures. The dye photodegradation rate constants increased in the following order: pure films < films modified with Ag, 10−4 M < films modified with Ag10−3 M < films modified with Ag10−2 M. The Ag modification and the heterojunction of the composites contributed to trapping and transfer of the electrons. Therefore, the photogenerated charges had a longer lifetime, resulting in a strengthened photocatalytic ability of the ZnO/Ag and TiO2/Ag films.

Plasma modified Co3O4 nanoparticles for catalytic degradation process through enhanced peroxidase-like activity

This study highlights a simple and efficient nanochemistry-based approach for the effective degradation of triphenylmethane and toxic dye, malachite green (MG) using Argon cold plasma-modified cobalt oxide nanoparticles (Ar-Co3O4-NPs). Synthesized particles were characterized using scanning electron microscope, X-ray diffraction, and Fourier-transform infrared spectroscopy. The peroxidase-mimic activity of Co3O4-NPs was evaluated, and the results confirmed that the catalytic activity of Co3O4-NPs was enhanced after plasma modification. The decomposition of MG was tested using the improved catalytic activity of Ar-Co3O4-NPs in model aqueous solution. The results indicated the ability of 0.16 g/mL Ar-Co3O4-NPs to completely degrade 40 µM MG within 70 min with a decolorization efficiency of 96.78%. Experimental conditions were optimized for maximum MG removal. Gas chromatography-mass spectrometry was used to determine the byproducts of MG degradation, and the findings indicated the production of less toxic products. The toxicity of the resultant metabolites of MG degradation was evaluated against E. coli and B. subtilis and the results confirmed less toxic product formation. Artificial neural networks (ANNs) were used to model the catalytic degradation data, and the strong correlation between experimental observations and ANN model predictions suggested that the designed model could accurately predict MG dye removal efficiency under different operating conditions.

Electrochemical degradation and mineralisation of organic dyes in aqueous nitrate solutions

Electrochemical treatment of organic matter for environmental remediation necessitates the development of cheap and robust electrodes that are chemically and structurally stable. To address this challenging requirement, we demonstrate a new electrochemical approach using a simple copper electrode under cathodic conditions to electrochemically generate reactive nitrosonium ions for the degradation of different classes of synthetic organic dyes. This could be achieved in an aqueous HNO3/KNO3 electrolyte at a relatively low cathodic potential of −0.5 V RHE at room temperature. UV–visible absorption spectroscopy, Raman spectroscopy, liquid chromatography – mass spectrometry and total organic carbon measurements revealed the rapid decolorisation and mineralisation of several dye types such as triarylmethane dyes (crystal violet, cresol red), an azo dye (methyl orange) as well as a sulfur containing thiazine dye (toluidine blue). The total organic carbon content of a 50 mg L−1 methyl orange solution was found to decrease by 83% after 1 h of electrolysis. Promisingly, locally sourced river and creek water samples spiked with 50 mg L−1 methyl orange were also successfully treated for up to 6 cycles at a simple Cu electrode, demonstrating potential for the remediation of polluted waterways.

Degradation by hydrolysis of three triphenylmethane dyes: DFT and TD-DFT study

Degradation by hydrolysis of three triphenylmethane dyes: DFT and TD-DFT study