Cationic Textile Dye Research Articles

Preparation of nanostructured magnetite with plasma for degradation of a cationic textile dye by the heterogeneous Fenton process

The surface and catalytic properties of natural magnetite were modified using plasma treatment, and were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, N2 adsorption–desorption, and scanning electron microscopy. The results show the production of nanostructured magnetite, from its natural particles, with an average diameter in the range of 20–40 nm. The application of nanostructured magnetite in a heterogeneous Fenton process was investigated in the degradation of Basic Blue 3 (BB3) as a model pollutant in aqueous solution. The effects of operational parameters were studied with respect to decolorization efficiency. The application of a nanostructured magnetite catalyst allows the Fenton process to be operated at milder pH conditions (a pH of 5). A decolorization efficiency of 96% in the presence of plasma-treated magnetite was approximately two times higher than that of untreated magnetite. Negligible iron leaching and a simple separation of used catalyst using an external magnetite field are merits of using plasma-treated magnetite in heterogeneous Fenton process.

Spectrophotometric Investigation of the Interactions between Cationic (C.I. Basic Blue 9) and Anionic (C.I. Acid Blue 25) Dyes in Adsorption onto Extracted Cellulose from Posidonia oceanica

Extracted cellulose from Posidonia oceanica was used as an adsorbent for removal of a cationic (Basic blue 9, BB) and anionic textile dye (Acid blue 25, AB) from aqueous solution in single dye system. Characterization of the extracted cellulose and extracted cellulose-dye systems were performed using several techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), zeta potential and Boehm acid– base titration method. Adsorption tests showed that the extracted cellulose presented higher adsorption of BB than AB in single dye system, revealing that electrostatic interactions are responsible, in the first instance, for the dye– adsorbent interaction. In single dye systems, the extracted cellulose presented the maximum adsorption capacities of BB and AB at 0.955 and 0.370 mmol.g-1, respectively. Adsorption experiments of AB dye on extracted cellulose saturated by BB dye exhibited the release of the latter dye from the sorbent which lead to dye-dye interaction in aqueous solution due to electrostatic attraction between both species. Interaction of BB and AB dyes were investigated using spectrophotometric analysis and results demonstrated the formation of a molecular complex detected at wavelengths 510 and 705 nm when anionic (AB) and cationic (BB) dye were taken in equimolar proportions. The adsorption isotherm of AB, taking into account the dye-dye interaction was investigated and showed that BB dye was released proportionately by AB equilibrium concentration. It was also observed that AB adsorption is widely enhanced when the formation of the molecular complex is disadvantaged.

Thermodynamics and kinetics of adsorption of a cationic dye onto sepiolite

The adsorption kinetics and thermodynamics of Maxilon Red GRL (MR-GRL), a cationic textile dye, onto sepiolite were investigated in aqueous solution in a batch system. The effect of contact time, stirring speed, initial dye concentration, initial solution pH, ionic strength, and temperature was studied. The initial tested concentrations of MR-GRL solution were 1.5 × 10−3, 2.0 × 10−3 and 2.5 × 10−3 mol/L. The effect of pH was analyzed in the pH range from 5 to 10. The effect of ionic strength was investigated at 0.001–0.100 mol/L NaCl salt concentrations. The experiments were carried out at 288, 298, 308, and 318 K set with a thermostat. The all parameters significantly influenced the adsorption rate and capacity. Experimental data were fitted to pseudo-first order, second-order, Elovich equation, mass transfer, and intra-particle diffusion models. The adsorption kinetics data showed that this process can be described by the pseudo-second-order model, from which the rate constant and the adsorption capacity were determined. The thermodynamic activation parameters such as the activation energy, enthalpy, entropy, and Gibbs free energy were determined. The value of the standard enthalpy change (19.92 kJ/mol) indicates that the adsorption is physical in nature involving weak forces of attraction and is also endothermic. The results showed the applicability of this clay as an efficient adsorbent for cationic dyes.

Adsorption kinetics of a cationic dye from wastewater

The adsorption kinetics and thermodynamics of Maxilon Blue 5G, a cationic textile dye, onto perlite were investigated in aqueous solution in a batch system for determining the effect of contact time, stirring speed, initial dye concentration, initial solution pH, ionic strength and temperature. Experimental data were evaluated according to the pseudo-first, second-order and the Elovich equation, mass transfer and intra-particle diffusion models, and it was found that adsorption kinetics can be described according to the pseudo-second-order model, from which the rate constant and the adsorption capacity were determined. The thermodynamic activation parameters, such as activation energy, enthalpy, entropy and Gibbs free energy, were determined. The obtained results confirmed the applicability of this mineral as an efficient adsorbent for cationic dyes.

Application of Polythiophene–Sawdust Nano-Biocomposite for Basic Dye Removal Using a Continuous System

A novel dye adsorbent was developed by a poly (3-methyl thiophene) nano layer coated onto sawdust obtained from Narra wood. The polymer was synthesized chemically under in-situ conditions on the surface of the sawdust. Methylene blue, a typical cationic textile dye, was employed as a test probe for adsorption experiments. The experiments were conducted in both batch and fixed-bed column systems. The effects of variables such as pH, initial dye concentration, flow rate, and bed height were investigated. The Thomas dynamic model was applied to calculate the sorption capacity of adsorbents. Based on the breakthrough curves analysis, the highest column capacity of 191 mg/g was obtained. The introduced nano-biocomposite was found to be more than seven times more efficient than unmodified sawdust for methylene blue removal. The regeneration of the modified sawdust is quite possible using 0.10 M HCl in ethanol as a washing solution with high efficiency.

Decolorization of textile dye CI Basic Yellow 28 with electrochemically generated active chlorine

Reaction of the indirect electrochemical decolorization of cationic textile dye CI Basic Yellow 28 with electrochemically generated “active chlorine” has been studied, using UV–Vis spectrophotometry, ion chromatography, organic carbon analysis, and cyclic voltammetry. Decolorization has been investigated on Ti/PtOx anode for different currents in the range of 50–200mA, sodium chloride concentration in the range from 5 to 25gdm−3, and dye concentration from 10 to 70mgdm−3. The optimum electrolysis conditions and possible active species have been suggested.

Liquid−Liquid Extraction of Basic Yellow 28, Basic Blue 41, and Basic Red 46 Dyes from Aqueous Solutions with Reverse Micelles

The removal of 2-[[(4-methoxyphenyl)methylhydrazono]methyl]-1,3,3-trimethyl-3H-indolium methyl sulfate (Basic Yellow 28), 2-[N-ethyl-4-[(6-methoxy-3-methyl-1,3-benzothiazol-3-ium-2-yl)diazenyl]anilino]ethanol methyl sulfate (Basic Blue 41), and N-benzyl-4-[(1,4-dimethyl-1,5-dihydro-1,2,4-triazol-1-ium-5-yl)diazenyl]-N-methylaniline bromide (Basic Red 46) cationic textile dyes from model wastewater by liquid−liquid extraction with reverse micelles was performed with isopentanol as a solvent and sodium dodecylsulfate as an anionic surfactant. The dye concentration in both aqueous and organic phase was determined by visible spectrophotometry analysis. The influence of dye and surfactant initial concentrations on the solute partition coefficient and percentage of removal were studied. The partition coefficient and percentage of removal increase with the decrease in initial dye concentration and with the increase in surfactant concentration.

Adsorption of binary mixtures of cationic dyes

Adsorption of cationic textile dyes namely, C.I. Basic Blue 41 and C.I. Basic Red 18 onto granular activated carbon (GAC) and silkworm pupa (SWP – a natural adsorbent) has been investigated for single and binary solute systems. Equilibrium isotherms were conducted for two, single solute systems and three binary combinations of the dyes. Although adsorption of C.I. Basic Red 18 on SWP showed no correlation with the Langmuir, Freundlich or Myers models, the Freundlich equation described the adsorption of Basic Blue 41 well and the Myers equation correlated reasonably well the two dyes on GAC. Of the multi-component models studied, the ideal adsorbed solution theory (IAST) gave reasonable predictions of the binary systems of the dyes on GAC but it failed to predict the binary system on SWP. The adsorption on SWP was shown to occur by chemisorption which was not affected by the presence of molecular oxygen.

Synacril® Black AN: A New Stain for Normal and Abnormal Human Megakaryocytes

After methanol fixation and ribonuclease digestion, normal and abnormal human megakaryocytes displayed intense red-purple coloration of the cytoplasm and dark brown nuclei when stained with the cationic textile dye Synacril black AN. In other marrow cells, cytoplasm stained cream color or pale blue in the case of eosinophils. In eosinophils, granules stained pink. As a complement to more complex immunologic technics, staining of megakaryocytes with Synacril black AN may represent a rapid screening method for identification of these cells.