Soluble Dye Research Articles

Chitosan intercalated bentonite as natural adsorbent matrix for water-soluble sappanwood dye.

Chitosan-bentonite clay composite was prepared for use as adsorbent matrix of water-soluble natural dyes. The addition of chitosan resulted in a relatively rough texture of the composite compared with bentonite. XRD analysis showed that a basal d001-space value of the composite (15.545 Å) is higher than that of bentonite clay (14.525 Å) which indicates that chitosan was intercalated into the layer of clay. FT-IR and SEM measurement also suggested that new compound was formed. Water soluble dye extracted from sappanwood was adsorbed onto chitosan-bentonite clay composite at 81.5% adsorption capacity. The dye-adsorbed composite showed different color shade at different pH values. The color stability was investigated under sunlight, fluorescent light, 45 °C, ambient temperature and dark condition for 4 weeks, and the color change of the sappanwood dye-adsorbed composite is less than that of the unadsorbed sappanwood powder in all conditions. The composite greatly improved the color stability of sappanwood dye about five time in the extent. The results of this work showed high potential of the chitosan-bentonite clay composite to be employed as adsorbent matrix for water soluble dyes and help increasing the color stability thus wider its use in industry.

Nanostructured GaOOH modified with reactive yellow, red and blue water-soluble dyes

Water soluble reactive dyes are used to modify nanostructured GaOOH. The resulting particles showed excellent stability in water solutions. The materials were characterized by Scanning electron microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) to assess changes due to the dye functionalization. SEM revealed changes in size after dye modification. XPS confirmed the presence of the dyes on the nanostructured materials and assessed changes in functional groups due to use of different type of modification and concentrations of dyes. The reported approach to stabilize the nanostructured GaOOH provides a simple and environmentally friendly route to tune the properties of wide band gap semiconductor materials.

Catalytic Degradation of Methyl Orange and Selective Sensing of Mercury Ion in Aqueous Solutions Using Green Synthesized Silver Nanoparticles from the Seeds of Derris trifoliata

In the present study, bio-augmented silver nanoparticles with Derris trifoliata seed extract (AgNP-DT) have been developed. Formation of AgNP-DT has been confirmed with X-ray diffraction (XRD), High resolution transmission electron microscopy (HRTEM) and Fourier-transform infrared spectroscopy (FTIR). Even though introduced for the first time as a catalyst owing to high surface area, the as-prepared nanoparticles showed one of the best catalytic activity in the reduction of a water soluble azo dye–methyl orange. An incredible pseudo-first order rate constant (0.3208 min−1) and activity parameter (1086 s−1 g−1) were obtained for the catalytic reduction of methyl orange with 4.9 μg AgNP-DT. Furthermore, AgNP-DT exhibits a good selectivity and sensitivity towards mercury(II) ions over other metals in aqueous solution. Absorbance of AgNP-DT exhibits a good linear relationship against concentration of Hg2+ with a limit of detection (LOD) of 1.55 μM. The mechanism of sensing activity of AgNP-DT was elucidated by measuring the variation in the zeta potential of the system with increasing concentration of Hg2+. Moreover the proposed method could be practicably applied for the detection of Hg2+ in real water samples with a percentage recovery in range of 91.41–108.07%.

Functional Chitosan Derivative and Chitin as Decolorization Materials for Methylene Blue and Methyl Orange from Aqueous Solution.

Dyes are classified as one of the major pollutants of water. They have negative impacts not only on environment but also on human health. In fact, wastewater that contains these harmful substances requires many types of treatments. Therefore, alternative methods and adsorption agents are needed. Herein, we propose to evaluate the decolorization of methylene blue (MB) and methyl orange (MO) as two models of soluble dyes from water using chitin and chitosan-graft-polyacrylamide. Furthermore, the applicability of these biomacromolecules as alternative adsorption agents, their sticking probability and desorption were also examined. Experimental parameters such as dye concentration, contact time, pH solution, adsorbent dosage and temperature were thoroughly examined for the grafted chitosan and chitin. The activation energy () and the thermodynamic variables (i.e., standard Gibb’s free energy (), standard enthalpy (), and standard entropy ()) were determined using the Van’t Hoff and Arrhenius equations. The sticking probability (*) model for MB and MO removal by chitin and the chitosan derivative demonstrated that both dyes were successfully removed under the proposed conditions. Desorption studies of MB and MO showed the reusability of both materials, suggesting their application for removing dyes from aqueous solution.

NON-THERMAL PLASMA MINI-REACTORS FOR WATER TREATMENT

The non-thermal plasma technologies (NTP) have been proved to be an alternative for air and water pollutants treatment. The goal of this paper is to emphasize the effect of the different non-thermal plasma mini-reactor configurations on the soluble organic compounds removal from water. Therefore, a soluble organic dye (Reactive Blue 19) solution has been treated in an NTP experimental reactor using different electrodes configurations. The influence of the different geometrical configuration of the reactors, such as electrodes shape and distance between them, on Reactive Blue 19 dye decolourization have been studied. The dye solution decolourization has been measured using colorimetric methods and upon the measurements results the energy efficiency EEf (g/kWh) of the dye removal have been calculated. The experimental results have shown that the electrochemical processes occurring in plasma and, consequently, the dye removal rate are significantly depending on the electrodes shape. The best results have been obtained for using a reactor having one sharp active electrode and one horizontal plan section for the outlet electrode, while the distance between them was 4 mm.

Separation of Dyes by Mixed Hydrotropic Thin Layer Chromatography

Now a days, aqueous solubility of drugs is major problem in pharmaceutical field. Generally for solubilization of drugs organic solvents generally prefer. But these solvents are toxic in nature, high cost, flammable and acts as pollutants. Organic solvents are not environment safe. Hydrotropic method is used to enhance water solubility of poorly water soluble drug by using various hydrotropes instead of organic solvents. As a Model sample Bromocresol green and phenol red was selected. To increase water solubility of poorly water soluble dyes, single and mixed hydrotropic method was selected. Both dyes soluble in optimized single hydrotropic solution like as 20% niacinamide, 25% niacinamide, 10% sodium benzoate and mixed hydrotropic solution like 10% Sodium citrate and 10% urea. For separation of both dyes from mixture Thin layer chromatography have been used. Silica gel G used as stationary phase on glass slide and hydrotropic solution used as a mobile phase in which sample was completely soluble. When single hydrotropic solution used as a mobile phase, separation of dyes was not obtained from mixture. Mixed hydrotropic solution of 10% sodium citrate and 10% urea used as mobile phase gives better result. Rf value of Bromocresol green and phenol red in mixed hydrotropic solution was found to be 0.51 and 0.82 respectively.

Spectrophotometric Determination of Chlordiazepoxide in Pharmaceutical Formulations via Oxidative Coupling Reaction with Phenothiazine

Abstract
 A sensitive, precise and reliable indirect spectrophotometric method for the determination of chlordiazepoxide (CDE) in pure and pharmaceutical dosage forms is described. The method is based on oxidative coupling reaction between amino group resulting from acidic decomposition of CDE with phenothiazine in the presence of sodium periodate to produce an intense green soluble dye that is stable and shows a maximum absorption at 602 nm. The calibration plot indicates that Beer’s law is obeyed over the concentration range of 0.1?50 µg/mL, with a molar absorptivity of 1×104 L/mol cm and correlation coefficient of 0.9994.All the conditions that affecting on the stability and sensitivity of the formed product were studied and optimized and the suggested method was effectively applied for the determination of CDE in commercial dosage forms.

A Novel Water Soluble Bipyrazolic Tripod Azoic Dye as Chemosensor for Copper (II) in Aqueous Solution

A novel copper (II) chemosensor based on water soluble azoic dye with bipyrazolic tripod moiety has been synthesized. The spectroscopic data’s of the presented chemosensor and its complex formation with several metal ions are studied in water via colorimetric titrations. The obtained results show that the developed chemosensor presents a high selectivity towards copper (II) in the presence of other metal ions in the typical pH range of biological systems with a detection limit of 0.84 μM.

Color-tunable particles through affinity interactions between water-insoluble protein and soluble dyes

This research is focused on the delivery of color using zein particles as a carrier and contributes to understanding the interactions between colorants and zein. Co-precipitation of purified zein protein with anionic dyes such as sulfonate group containing azo-dyes (patent blue sodium salt, azorubine, and fast green FCF) are used to prepare red, green, and blue colored nanoparticles. These dyes had electrostatic interactions with zein and they remained bound in the zein particles even after dialysis. This was not the case for purpurin, for with hydrogen bonding was expected as interaction. Upon increasing dye concentration, the particle sizes increased as a result of a change in the kinetics of precipitation, which was affected by the association between zein and the dye. However, the encapsulation efficiency continued to be very high and no plateau was reached for the used concentrations. The post-addition of dye on undyed zein particles was used to confirm that there is indeed a high affinity between the dye and the protein. The amount of free dye was determined and the affinity was again found to be high (dye adsorption <95%). The amount of dye incorporated into the particles and the resulting color were similar using both techniques. These results show that there is a high affinity between the zein protein and the dye, and may be exploited to produce bio-based and optically-functionalized nanoparticles using zein as a carrier.

Synergism and Interfacial Property Study of Sodium Lauryl Ether Sulfate and Polysorbate 80 at the Air–Water Interface

AbstractAdsorption and micellization behavior of sodium lauryl ether sulfate (SLES) and Polysorbate 80 (PS80) was investigated using equilibrium and dynamic surface tension and foaming measurements. Critical micelle concentration (CMC) was determined using surface tension and dye (Sudan red III) solubilization method with the help of the Wilhelmy plate method and ultraviolet–visible spectroscopic method, respectively. The strength of the interaction for micellization and adsorption between the mixtures are calculated using the β interaction parameter. The SLES‐PS80 mixture shows synergistic interaction with β = −8.0. The dynamic and foaming behavior at constant bulk concentration showed a higher t * value with lowest foaming at 50% mole fraction of SLES. The emulsification index (EI) of pure SLES, pure PS 80, and 1:1 SLES‐PS 80 composition was studied using neem, karanja, and sunflower oils. Karanja and sunflower oils show a higher EI for mixture than the pure surfactants, whereas neem shows a lower EI for mixture than pure surfactants.

Characterization and properties of new color-tunable hybrid pigments based on layered double hydroxides (LDH) and 1,2-dihydroxyanthraquinone dye

In this paper a novel, simple method for synthesis of lake pigments based on 1,2-dihydroxyanthraquinone dye and LDH carbonates was proposed. LDHs were modified with 1,2-dihydroxyanthraquinone, transforming the soluble dye into a new kind of hybrid lake. In result, the solvent resistance and photostability of the chromophore were improved, which may be attributed to strong dye–LDH interactions. TOF-SIMS technique was used for the first time to confirm the role of C14H7O4Mg+ and C14H6O5Al− ions in the formation of the hybrids. Alizarin lakes have been recognized as a new class of colorants which demonstrated good color characteristics and chemical stability.

Mesoporous zinc silicate bio-composite: Preparation, characterization and in vitro evaluation

Abstract Zinc silicate composites bring together the unique properties of silica and zinc giving rise to a material that possesses biocompatibility, bioactivity, antibacterial activity, ability to stimulate osteogenesis and differentiation. Recently, owing to such exceptional features, zinc silicate based biocomposites have found application as a biomaterial. In this study, we report a novel one-pot method to engineer porous nanostructured mesoporous zinc silicate material (mZS). The synthesized rod-like particles with pores of size 2–3 nm had a surface area of 292.065 m2/g and were found to be pure and amorphous in nature. The material exhibited antibacterial activity against Gram positive Staphylococcus aureus where Minimum Inhibitory Concentration (MIC) of mZS was found to be around 0.15 mg/mL and Minimum Bactericidal Concentration (MBC) was around 0.9 mg/mL. It was found to be biocompatible towards mouse mesenchymal stem cells (C3H10T1/2) and human osteoblastic cells (MG-63). The synthesized material was stable even after 32 days and exhibited only minor structural changes due to dissolution when biodegradability studies were done in PBS. In addition, the ability of the material to carry small molecules was assessed using a water soluble cationic dye, Methylene Blue. The adsorption capacity of mZS for methylene blue dye was found to be around 47.28 ± 0.57 μg/mg of particle. The results indicated that synthesized mZS can efficiently load small molecules and possesses properties like antibacterial activity and biocompatibility, thus, might prove to be a promising biomaterial as bone fillers, bioactive coatings and bone cements.

Synthesis of non-ionic and enzyme-responsive bolaamphiphiles for drug delivery applications

Nanoscale drug delivery systems devised from biocompatible and biodegradable molecules with functional groups which are readily amenable to external stimuli, have become a promising approach to circumvent the pitfalls associated with the hydrophobic drugs concomitant with the amplification of drugs’ action. Taking the cognizance of advantages offered by nanostructures and also in search of amphiphiles with intended biomedical applications, a novel and elite family of amphiphilic system that can self-assemble into enzyme-responsive supramolecular architectures has been synthesized via a chemo-enzymatic approach using an immobilized enzyme (lipase) from Candida antarctica (Novozym 435) and employing biocompatible starting materials, i.e. p-hydroxybenzoic acid, monomethoxypolyethyleneglycol (mPEG), and glycerol. The aggregation behavior of the resulting bolaamphiphiles have been studied using critical aggregation concentration and dynamic light scattering measurements, further supplemented by cryogenic transmission electron microscopic studies. The developed amphiphiles render efficient solubilization of model hydrophobic drugs and dyes, e.g. Nile red, nimodipine, and curcumin in aqueous solution. Moreover, the results demonstrate that a subtle structural modulation of the amphiphilic system alters the transportation behavior of the guest molecule. The investigation of the enzyme-responsive behavior of the synthesized bolaamphiphiles using a hydrolase enzyme, Candida antarctica lipase reveals that amide based nanocarriers disassemble and release the encapsulated cargo on incubation with the enzyme. 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay unravels negligible cytotoxicity of the bolaamphiphiles at the tested concentrations, indicating their relevance in the development of nanocarriers for biomedical applications.

Adsorptive removal of acid yellow 17 (an anionic dye) from water by novel ionene chloride modified electrospun silica nanofibres

Sorbents for environmental remediation, based on Advanced Materials, have attracted research interest because of their better selectivity, reusability and resolution of disposal problems at end-of-life, relative to conventional activated carbon based sorbents. The adsorption behavior of non-calcinated, electrospun Silica nanofibres, with no additional co-electrospun fibre-forming polymer present, has not been much reported. This work describes the preparation and performance of a recyclable nanofibrous silica adsorbent, to effectively capture a highly water soluble anionic dye, Acid yellow 17(AY17), from water. The physical structure and chemical composition of the electrospun silica nanofibres and its modified form were elucidated by their infrared and X-ray Diffraction spectra, Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), and nitrogen adsorption-desorption analysis. The adsorptive removal efficiency, of the modified and as-is silica nanofibres, against AY17 was 100% and 54.6%, respectively. Improved adsorption is achieved through micropore formation, and introduction of positively charged moieties on alkali etching of the silica nanofibres, after surface protection with the prepared ionene chloride polyelectrolyte. The nature of equilibrium adsorption data was more favorably described by non-linear form of the Freundlich isotherm, and the non-linear pseudo-second-order kinetic model. The adsorption of AY17 onto the modified silica nanofibres was an exothermic process, with larger decrease in free energy compared to the endothermic process in silica nanofibre.

Physicochemical properties and bioactivity studies of synthesized counterion coupled (COCO) gemini surfactant, 1,6-bis(N,N-hexadecyldimethylammonium) adipate

In the present investigation, we report the surface activity, micellar, thermodynamic properties and bioactivity studies of synthesized counterion coupled (COCO) gemini surfactant, 1,6-bis(N,N-hexadecyldimethylammonium) adipate (16-6-16). In aqueous solution, the CMC (critical micelle concentration) of 16-6-16 was measured by electrical conductivity, surface tension, dye solubilization and fluorescence measurements techniques. The surface activities and surface properties of the COCO gemini surfactant, 16-6-16 were evaluated. The CMC as well as Amin (the minimum area per surfactant molecule at the air/water interface) decrease and the Γmax (the maximum surface excess concentration at the air/water interface) increases with increasing the temperature. We also report the thermodynamics of 16-6-16 and evaluated Gibbs energies. The aggregation number (Nagg) of 16-6-16 is reported. The bioactivity studies of 16-6-16 showed to be nontoxic, biocompatible and having good antibacterial activity.

Micellization of poly(ethylene oxide)-poly(propylene oxide) alternating multiblock copolymers in water

The micellization behaviors of two types of the poly(ethylene oxide) (PEO) - poly(propylene oxide) (PPO) alternating multiblock (AMB) copolymers in water, which have a different weight fraction of PEO (fPEO), have been investigated. Surface tension measurements reveal that the molecular area at air/water interface of the PEO-PPO AMB copolymers is significantly small. This indicates that the solubility of the unimer of PEO-PPO AMB copolymers in water is quite low and structural changes occurs when the unimer transfers from the aqueous media to the interface. The critical micelle concentration (CMC) and critical micelle temperature (CMT) have been determined by the fluorescent probe method with the dye solubilization. The CMC of the PEO-PPO AMB copolymer in water is lower by 100 times than that of the PEO-PPO-PEO triblock copolymer (Pluronics) having a similar fPEO. The small angle X-ray scattering and the dynamic light scattering measurements suggest that the unimer of the PEO-PPO AMB copolymer forms a core-corona structure below CMT, and then a core-corona multimer micelle with the 14–18 nm of radius appears above CMT. The thermodynamic quantities of micellization of the PEO-PPO AMB copolymer indicates that the PPO blocks in the unimer are loosely assembled in the core and stabilized through the hydrophobic interaction. The difference in micellization between PEO-PPO AMB copolymers and Pluronic arises from the difference in the block arrangement.

Preparation of color polymeric nanomaterials containing dispersed dye by sunflower oil synergy and color transfer property by digital inkjet printing

The color polymeric nanomaterials containing highly dispersed dye molecules were designed and prepared by sunflower oil synergy microemulsion polymerization. The color nanoparticles can be applied to coat on the PET fabrics by digital inkjet printing technique. The sunflower oil as a dye solubilization and polymer plasticizer was used in the polymerization process. The structure and morphology of polymeric nanoparticles containing dispersive dyes were characterized by Fourier transform infrared spectrum (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray powder diffraction (XRD) analysis. The color transfer properties from nanoparticle coating into PET fabrics by digital inkjet printing were discussed. Three color nanoparticles were homogeneous nanospheres with regular shape and size below 100 nm. The nano-balls were swelled by sunflower oil. The dye is evenly dispersed in colloidal nanoparticles. The color transfer rate of three nanoparticles containing disperse dyes with 2.43% oil by digital inkjet printing method were 97.1%, 95.3%, and 96.1%, respectively. The color transfer rates of three color nanomaterials with sunflower oil were obviously improved. The fastness properties of the PET fabrics printed with three nanoparticles with oil were excellent.

Phase Separation of Amphiphilic Drug Amitriptyline Hydrochloride in the Presence of Additives: Role of Ethanol

In this work, the effect of ethanol (EtOH) at different weight percentages (wt %) (0, 5, 10, and 15% w/w) is accounted for in the clouding phenomena of the AMT drug with/without additives (inorganic salts and conventional and gemini surfactants). The critical micelle concentration (cmc) and degree of counterions dissociation (α) of AMT solution at 30 °C in SP buffer (pH 6.7), studied through conductometric studies, are found to be enhanced with the increase in ethanol content due to the reduction in the dielectric constant of mixed media. A dye solubilization study performed under identical physicochemical conditions exhibited supporting results. Clouding could not be observed in 20 wt % EtOH–WR mixed media at pH 6.7. The effects of additives on the CP in 15 wt % EtOH–WR at a pH of 6.95 were also studied. Furthermore, the effect of pH (range 6.7 to 7.15) on the CP in the presence of KCl at the same composition of the mixed media reduce the clouding temperature due to the deprotonation of AMT headgroups. F...

Photocatalytic Degradation of Methylene Blue Dye Using Silica Oxide Nanoparticles as a Catalyst.

The present research deals with the development a fast and low-cost method for removing color dye from water using nanosized semiconductors SiO2 as photocatalyst. The studies of kinetic photocatalytic degradation were carried out on an aqueous solution of soluble methylene blue dye, which contained SiO2 nanoparticles and under an ultraviolet light source. Different parameters affecting the process have been studied: catalyst concentration, dye concentration, temperature, and pH of solution. The color variation was detected at three absorption bands (662, 293, and 243 nm). It was found that the dye completely degraded in 90 s, using 10 g/L SiO2 nanoparticles at 25 °C and pH 1.5 and 11.0. The adsorption of the dye well-fitted pseudo-second-order kinetic models. The Langmuir-Hinshelwood model was acquired to analyze the photocatalytic degradation process. A possible molecular mechanism for photocatalytic degradation of the dye by SiO2 nanoparticles is also given.

Spectrophotometric Determination of Sulfamethoxazole in Pure and in Pharmaceutical Preparations by Diazotization and Coupling Reaction

A highly sensitive, simple and accurate spectrophotometric method has been developed for quantitative determination of sulfamethoxazole(SMX) in both pure form and pharmaceutical preparations. In this method SMX is diazotized with equimolar of sodium nitrite(NaNO2) in acid medium of hydrochloric acid to form diazonium ion , which is reacted with 2,4,6-trihydroxybenzoic acid in alkaline medium of NaOH to form a yellow water soluble azo dye that has absorption maximum at 416 nm versus reagent blank. Beer's law is obeyed over the concentration range 0.2-16 µg. ml-1 with an excellent determination coefficient (r2= 0.9996) and molar absorptivity 1.84×104 l.mol-1.cm-1. The recoveries are obtained in the range of 97.8 - 99.8% and the relative standard deviation is better than ±0.23% . The stoichiometry of the resulting azo dye has been also worked out and it is found to be 1:1 SMX: 2,4,6-trihydroxybenzoic acid. This method has been applied successfully for the determination of SMX in pharmaceutical preparations (tablets and oral suspension).