Dye Mixture Research Articles

Optimization of a Binary Dye Mixture Adsorption by Moroccan Clay Using the Box-Behnken Experimental Design

Optimization of a Binary Dye Mixture Adsorption by Moroccan Clay Using the Box-Behnken Experimental Design

Stability and safety of transbronchial dye mixture for preoperative localization in a porcine model.

For thoracoscopy, the usefulness of a dye mixture of indigo carmine and Lipiodol for localizing lung lesions has been reported. However, little is known about the stability and safety of this dye mixture injected on the visceral pleura through a bronchoscope. Porcine models were divided into three groups according to the detection time of the dye mixture: group A with a detection time of 4h; group B, 8h; and group C, 24 h. A dye mixture of indigo carmine and Lipiodol (0.5mL each) was sprayed onto the visceral pleura both in the ventral and dorsal regions via a spray catheter. Twelve markings were created on the visceral pleura of the porcine lung (six ventral and six dorsal) in the six porcine models. At predetermined detection times, all 12 dye markings (100%) were visible on the visceral pleura. The mean longest diameter of the dye marking in the ventral and dorsal regions was 18.8 mm and 24.3 mm, respectively. In groups B and C, pathological changes in the lymphatic system, such as lymphatic dilatations, were found; minimal changes were found in group B, however, these changes with oval-shaped lymphatic cysts and Lipiodol accumulation, were more evident in group C. The dye mixture of indigo carmine and Lipiodol had reliable stability and visibility. In terms of safety, it may be necessary to check the dye mixture on the lung surface within 8h.

Phthalimide based new photocatalysts featured with highly selective photodegradation of azo-dyes and good photocatalytic activity in both homogeneous and heterogeneous systems

• Phthalimide (PI) preferentially photodegrades azo dye in mixture with non-azo dye. • PI shows good photocatalytic activity in homogeneous and heterogeneous system. • Halogenation of PI tunes the photocatalytic performance. • PI with selective photodegradation of dye is promising in environment remediation. Selective degradation of the target pollutants allows delicate manipulation of the environmental remediation process via photocatalysis, and has attracted much attention in recent years. Herein, we report the preparation and photocatalytic behaviors of an organic semiconductor of phthalimide (PI). It is found that PI could effectively degrade the azo-dyes under UV irradiation in either heterogeneous or homogeneous reaction system, which is rarely reported for the photodegradation of the dyes. In comparison, the halogenation of PI has an adverse effect on the photocatalytic activity of corresponding PI derivatives. Moreover, PI is used to photodegrade the mixtures of azo-dyes and non-azo dyes. It is found that PI achieves highly selective photodegradation of the azo-dyes in a heterogeneous reaction system, while its halogenated derivatives exhibit lower selectivity. By contrast, no preferential photodegradation is observed in the homogeneous methanol solution. It is proposed that the regular π-π stacking conjugated structure of the PI based molecules are responsible for the selective photodegradation behaviors. The work offers new approaches for the development of advanced organic molecule photocatalysts with desirable features including selective photodegradation and efficient degradation of dyes in both heterogeneous and homogeneous photocatalysis.

Exploitation of green synthesized chromium doped zinc oxide nanorods (NRs) mediated by flower extract of Rhododendron arboreum for highly efficient photocatalytic degradation of cationic dyes Malachite green (MG) and Fuchsin basic (FB)

In this work, green method to synthesize chromium-doped zinc oxide (ZnO) nanorods (NRs) using an aqueous flower extract from Rhododendron arboretum is explored. Herein, chromium-doped ZnO NRs were prepared with different amount of chromium doping, varied as 2–10%. The green synthesized products underwent substantial analysis through X-ray diffraction (XRD), spectroscopic such as ultraviolet spectroscopy(UV-Vis) and scanning electron microscopy (SEM) methods. All samples were found to have hexagonal wurtzite ZnO, with average particle sizes of 52.41, 56.6, 54.44, 53.05, and 56.99 nm, respectively, for 2, 4, 6, 8, and 10% chromium doping in ZnO NRs. The Cr-doped ZnO NRs exhibited remarkable photocatalytic degradation activity of cationic dyes under UV-light, i.e., Malachite Green and Fuchsin Basic with degradation of 99.604 and 99.881%, respectively in 90 min. The reusability tests for these green synthesized Cr-doped ZnO NRs have also been carried out, showed 9–11 cycles with 85% of degradation efficiency. In addition, the Cr-doped ZnO NRs exhibited high selectivity for cationic dyes when experiments against mixture of dyes were performed. Photodegradation kinetics followed the pseudo-first-order model. The flower-extract-stabilized chromium-doped ZnO NRs demonstrated high photocatalytic activity toward malachite green and fuchsin basic dyes, potential material for pollution remediation.

Photopolymerised Coatings with Nanopigments Based on Dye Mixtures

The properties of new coatings with nanopigments (NPs) prepared by the dye mixture treatment of montmorillonite modified with cationic surfactants were investigated. The colorimetric parameters of polymer films with nanopigments were determined. The mutual interference of the dyes in their adsorption on nanoparticles and their colourfastness (photostability) to light was analysed. The properties of oligomer/monomer compositions with synthesised nanopigments designed for the printing of non-metallic surfaces were discussed. The structure of nanopigments and polymerised oligomer/monomer compositions was revealed by small-angle X-ray diffraction, UV–Vis spectra, and atomic force microscopy. NPs with a wide colour range were prepared using dye mixtures. One other advantage of these NPs over NPs based on individual dyes is the possibility to increase the total concentration of the colouring components in the NPs and to increase the colourfastness.

Colorimetric Probe for Mn2+ Using a Mixture of an Anionic Dye and a Cationic Polyelectrolyte in an Aqueous Solution.

A novel colorimetric probe for Mn2+ was easily prepared by mixing negatively charged alizarin complexone (ALC) with positively charged poly[bis(2-chloroethyl)ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] (PQ-2) in aqueous solutions at pH 6.0. Upon adding Mn2+ to ALC alone, the solution underwent no distinct color change, while the mixture displayed selective detection of Mn2+ over different physiological and environmentally significant metal ions by an efficient naked-eye color change from red to purple. The detection of Mn2+ by the mixture was achieved from the electrostatic interactions between ALC and PQ-2. The quantitative determination of Mn2+ was obtained by spectrophotometric measurement and naked-eye observation. This sensing strategy can be an attractive approach for the development of new colorimetric probes due to the advantages such as no organic synthesis, facile fabrication, and simple visual detection.

Culture of leukocyte-derived cells from human peripheral blood: Increased expression of pluripotent genes OCT4, NANOG, SOX2, self-renewal gene TERT and plasticity.

There are few stem cells in human peripheral blood (PB). Increasing the population and plasticity of stem cells in PB and applying it to regenerative medicine require suitable culture methods. In this study, leukocyte populations 250 mL of PB were collected using a blood separator before that were cultured in optimal cell culture medium for 4 to 7 days. After culturing, stemness characteristics were analyzed, and red blood cells were removed from the cultured cells. In our results, stemness markers of the leukocyte populations Sca-1+ CD45+, CD117+ CD45+, and very small embryonic-like stem cells CD34+ Lin- CD45- and CXCR4+ Lin- CD45- were significantly increased. Furthermore, the expression of stem cell genes OCT4 (POU5F1), NANOG, SOX2, and the self-renewal gene TERT was analyzed by quantitative real-time polymerase chain reaction in these cells, and it showed a significant increase. These cells could be candidates for multi-potential cells and were further induced using trans-differentiation culture methods. These cells showed multiple differentiation potentials for osteocytes, nerve cells, cardiomyocytes, and hepatocytes. These results indicate that appropriate culture methods can be applied to increase expression of pluripotent genes and plasticity. Leukocytes of human PB can be induced to trans-differentiate into pluripotent potential cells, which will be an important breakthrough in regenerative medicine.

Au and zincite assisted silica-titania nanocomposite coated fiber optic pH sensor: Structural thermal, and optical characteristics

Accurate pH evaluation is required in different fields including food science, agriculture, environmental monitoring, and medical research. The low-temperature sol-gel method is employed to synthesize the Au and zincite-assisted silica-titania nanocomposites for the pH assessment. A mixture of indicator dyes (phenol red, creosol red, phenolphthalein, and bromophenol blue) is encapsulated in mesoporous nanocomposites and coated on fiber optic. Crack-free, dense, and porous surface with low roughness and high thermal stability (≤500 °C) is observed for all three nanocomposites. Low roughness 4 nm, low refractive index 1.5, and high surface area 333 m2/g DST nanocomposite exhibited sensitivity 28.3 counts/pH which is greater than 17.5 counts/pH (DAuST) and 14 counts/pH (DZST). The fiber pH devices possessed reversible, stable, and fast response 0.19 s into pH 12 (DST), DZST ∼ 0.18 s, and DZST ∼ 0.22 s, without any leaching.

Effect of heat treatment to Clitoria Ternatea and Hibiscus Sabdariffa-based dye-sensitized solar cells' characteristics

In this paper, anthocyanin dyes produced from naturally occurring flowers of Clitoria ternatea and Hibiscus sabdariffa were used as sensitizers in dye-sensitized solar cells (DSSCs). The purpose of this study is to analyse the effect of pre-heat treatment towards the I-V performance of these two anthocyanins based-dye as natural dyes of Dye-Sensitized Solar Cell. The photovoltaic characteristics of Clitoria ternatea, Hibiscus sabdariffa and the combination of these flower-based dyes which supposedly produced a new purplish dye are investigated in this paper. The content of anthocyanin extracted from C. ternatea was evaluated using Ultraviolet-Visible Spectrophotometer (UV-VIS) to detect the light absorption behaviour. The performance of DSSCs was analysed with respect to the mix of anthocyanin-based extracts at varied pre-heated temperatures. Interestingly, the efficiency of C. ternatea-sensitized DSSC which the dye was pre-heated at 40°C increased significantly at almost 18 times higher than the C. ternatea's sample with non-heated condition. In addition, a new mixture dye of H. sabdariffa and C. ternatea excelled good improved values of cell efficiency, short-circuit current density and fill factor with 0.0023%, 24.244 μA/cm2, and 37.17%, respectively, compared than that of other fabricated samples. This mixed extract exhibited the greatest sensitization in the cell, which was consistent with the extract's broadest spectrum.

Low-Cost Graphene-Based Composite Electrodes for Electrochemical Oxidation of Phenolic Dyes

Electrochemical removal of organic pollutants represents an attractive methodology in water depollution. The key challenges for researchers comprise finding simple, affordable electrode materials with satisfactory efficiency in all ranges of pollutant concentration. Electrochemical oxidation of a mixture of phenol-based dyes: bromocresol green (BCG), cresol red (CR), and thymol blue (TB), in sulphate medium, at total concentration not exceeding 15 ppm, has been performed using simply prepared, low-cost composite electrodes, based on graphene nanoplatelets (GNP) and metallic oxides (TiO2 and SnO2) loaded on stainless steel substrate: GNP@SS, SnO2/GNP@SS, and TiO2/GNP@SS. Electrodes were characterised by XRD, FTIR, and electrochemical techniques. The degradation kinetics of initial dyes was tracked with UPLC and GC-MS chromatography for 6 h, at a current density of 10 mA/cm2. GC-MS analysis of the degradation products revealed oxidised aromatic compounds as the main products, while TOC analysis confirmed a total mineralisation extent in the range of 30–35%. The proposed degradation mechanism involves the attack of OH-radical, as the main oxidising agent, to the hydroxyl oxygens of dye phenolic rings. Obtained results provide useful information for the further development of affordable laboratory-scale and industrial systems for the complete removal of phenol-based compounds.

Closed-loop automatic gradient design for liquid chromatography using Bayesian optimization

Contemporary complex samples require sophisticated methods for full analysis. This work describes the development of a Bayesian optimization algorithm for automated and unsupervised development of gradient programs. The algorithm was tailored to LC using a Gaussian process model with a novel covariance kernel. To facilitate unsupervised learning, the algorithm was designed to interface directly with the chromatographic system. Single-objective and multi-objective Bayesian optimization strategies were investigated for the separation of two complex (n>18, and n>80) dye mixtures. Both approaches found satisfactory optima in under 35 measurements. The multi-objective strategy was found to be powerful and flexible in terms of exploring the Pareto front. The performance difference between the single-objective and multi-objective strategy was further investigated using a retention modeling example. One additional advantage of the multi-objective approach was that it allows for a trade-off to be made between multiple objectives without prior knowledge. In general, the Bayesian optimization strategy was found to be particularly suitable, but not limited to, cases where retention modelling is not possible, although its scalability might be limited in terms of the number of parameters that can be simultaneously optimized.

Removal of single dye and dye mixture from aqueous solution with alginate-coated calcined layered double hydroxide and illite clay composite beads

ABSTRACT Alginate-coated calcined layered double hydroxide and illite clay (Alg@CLDH@ Illite) composite beads were fabricated and tested for single and mixture dye adsorption from aqueous solution. Adsorption characteristics of the as-fabricated beads were assessed by using Methylene Blue (MB) and Congo Red (CR) as adsorbates. As-prepared samples were characterised by using X-ray diffraction (XRD), Thermogravimetry/Differential Scanning Calorimetry (TG–DSC), Fourier transform infrared spectroscopy (FTIR), and point of zero charge (pHpzc). The characterisations demonstrated that the incorporation of CLDH powder/clay mixture can not only enhance thermal stability but also can improve the adsorption performance. The adsorption kinetics of dyes onto composite beads followed the linear form of pseudo-second-order model and their equilibrium data were fitted well to the Freundlich model. The results showed that the Alg@CLDH@Illite composite is able to adsorb anionic and cationic dyes from a binary dye mixture with high sorption capacities in short time 50 min.

CuNCs-MOFs with hydrogen bonding sites: H2O-induced emission-enhanced phosphorescence-fluorescence conversion and high photo-Fenton catalytic performance

Clusters-based metal–organic frameworks (CMOFs) obtained through supramolecular interactions between clusters are expected to be a promising class of materials with interesting properties and attractiveness. Herein, CuNCs protected by AMT (3-amino-1,2,4-triazole-5-thiol) ligands were synthesized, which coordinated with Zn2+ to form a nanosheet CuNCs-MOFs structure, resulting in AIE and enhanced photoluminescence (QY = 1.1 %). Upon aging in H2O, H2O molecules are inserted into S-CuNCs by the hydrogen bond to support 3D microflowers structures, and weak phosphorescence conver to strong fluorescence (28.9 %), simultaneously. After drying, H2O molecules are released by F-CuNCs, which is labled with V-CuNCs, and then easily combined with H2O2, which can be catalyzed to OH by Cu+. Under UV irradiation, CuNCs-MOFs generate photogenerated electrons and holes. As-obtained electrons react with H2O2 to generate more OH, and then catalyze dyes. The remaining holes will also receive electrons given by the dyes. Under the irradiation of Xe lamp, the common three dyes, MB, MO, RB and antibiotic, tetracycline, can be completely degraded within 30 min. Furthermore, under the sunlight, the mixture of dyes and antibiotics also can be completely degraded after 100 min. V-CuNCs show excellent photo-Fenton catalytic performance and have the bright photocatalytic prospects in waste water.

The generally recognized as safe (GRAS) microalgae Haematococcus pluvialis (wet) as a multifunctional additive for coloring and improving the organoleptic and functional properties of foods.

This work proposes the application of astaxanthin-rich H. pluvialis wet paste (HPW) as a partial substitute for wheat flour in the preparation of filloas, a dish that combines the basic ingredients of industrial bakery. The nutritional and color profile of HPW-enriched samples was evaluated by comparative analysis with a mixture of synthetic food dyes. The highest content of carotenoids (798 ± 12 μg g-1) and fatty acids (76 ± 2 mg g-1) was obtained for a filloa fortified with H. pluvialis in contrast to a non-significant dye response. Subsequently, the color stability of the fortified filloa was evaluated over time (3, 6 and 9 days), as well as its physicochemical properties and microbiological profile. As a result, HPW provided filloas with a longer shelf life, brightness (*L), and texture, in comparison with a mixture of synthetic dyes. In addition, an inhibitory effect of HPW towards mesophilic aerobic microorganisms in the food was obtained.

Cobalt oxide nanoparticles by flame pyrolysis for efficient removal of mixed dyes

The cobalt oxide nanoparticles were prepared by low cost, gram scalable and environment friendly flame pyrolysis method by directly burning ethanolic solution of cobalt chloride. The cobalt oxide formation, functional group identification, morphology and particles size of as-synthesized nanoparticles were carried out using routine techniques viz. XRD, FTIR, FE-SEM, HR-TEM, Raman Spectroscopy and Vibrating Sample Magnetometer (VSM) analysis. The XRD pattern ensured the formation of Cobalt Oxide nanoparticles (CoO NPs). It also emphasized that synthesized CoO NPs are pure, crystalline and single phased. EDS ensured the purity of CoO NPs which contained only cobalt and oxygen. FE-SEM exhibited spherical morphology with particles size of around 30 nm aligned with Debye–Scherrer’s calculated average crystallite size of 20 nm. The optical direct band gap of CoO NPs was estimated using Kubelka - Munk function to be 2.97 eV. The magnetic behavior examined at room temperature by VSM confirmed the formation of CoO NPs with weak ferromagnetic nature. The CoO NPs were utilized successfully for the removal of mixed dye solutions. The CoO NPs showed excellent efficiency for the removal of mixture of hazardous dyes from the aqueous solutions. This makes CoO NPs valuable for removal of industrial dyes and colorants for the waste water treatment processes.

Toxic effects of Arianor Ebony hair dye on human cells.

To evaluate the risks of hair dye exposure, we investigated cellular and molecular effects of Arianor Ebony dye, which is a mixture of azo and anthraquinone dyes, used in the composition of the black color. Cytotoxicity, genotoxicity, and gene expression of relevant molecules of apoptotic and oxidative stress mechanisms were investigated in HepG2 cells exposed to Arianor Ebony. Results showed that the dye did not induce cytotoxicity to exposed cells at a concentration up to 50 µg/mL compared to the negative control. However, genotoxic assays indicated that the dye was able to damage the genetic material at a concentration of 25 µg/mL, with induction factor values of exposed cells two- to five-fold higher than those recorded for the negative control. Moreover, the lowest observed effect concentration was 12.5 µg/mL. For gene expression, relevant changes were observed in cytochrome c and caspase 9, which decreased in cells incubated with the dye in a dose-dependent manner when compared with the negative control. In parallel, the expression of genes for antioxidant enzymes was increased in exposed cells, suggesting the presence of metabolic routes that protect cells against the toxic effect of the dye, avoiding exacerbated cellular death. Results suggested that the dye disrupted cellular homeostasis through mitochondrial dysfunction, which may be hazardous to human health. Thus, further investigations are necessary to deeply understand the mechanisms of action of the dye, considering its toxic potential found in our ex vivo assays.

Synchronous fluorescence techniques for the detection and monitoring of selected fluorescent dyes in binary and multifluorophoric mixtures

The present study deals with non-destructive conventional emission, constant-wavelength synchronous fluorescence spectroscopy (CWSFS) and first derivative of CWSFS for selective estimation of two fluorescent xanthene dyes viz. rhodamine B (RhB) and fluorescein (Fls) in their binary and multifluorophoric mixtures via spike method in an aqueous environment. Various parameters (Δλ, pH, ionic strength, etc.) affecting these methods were optimized. Based on the results, measurement of RhB and Fls were performed at Δλ, 20.0 nm, pH 7.0, 25.0 ⁰C temperature and scan rate of 240.0 nm/min without their prior separation in mixtures. CWSFS and first derivative CWSFS measurements were carried out at 556.0 nm and 547.0 nm for RhB (R2 = 0.988 and 0.983) and 493.0 nm and 484.0 nm for Fls (R2 = 0.999 and 0.999) over the concentration range of both dyes at 0.10–0.70 mg/L. The mean percentage recoveries from aqueous binary mixtures of RhB and Fls were found to be 98.95, 99.97 (RhB) and 100.68, 100.73 (Fls) for CWSFS and first derivative CWSFS respectively. Results were statistically analyzed in terms of accuracy and precision.

Uncapped SnO2 quantum dots for selective adsorption, separation and photocatalytic degradation of a mixture of dyes

Adsorption and photocatalysis processes are of high significance for the remediation of toxic dyes in aquatic media.

Femtosecond laser patterned silicon embedded with gold nanostars as a hybrid SERS substrate for pesticide detection.

We have developed simple and cost-effective surface-enhanced Raman scattering (SERS) substrates for the trace detection of pesticide (thiram and thiabendazole) and dye (methylene blue and Nile blue) molecules. Surface patterns (micro/nanostructures) on silicon (Si) substrates were fabricated using the technique of femtosecond (fs) laser ablation in ambient air. Different surface patterns were achieved by tuning the number of laser pulses per unit area (4200, 8400, 42 000, and 84 000 pulses per mm2) on Si. Subsequently, chemically synthesized gold (Au) nanostars were embedded in these laser-patterned areas of Si to achieve a plasmonic active hybrid SERS substrate. Further, the SERS performance of the as-prepared Au nanostar embedded Si substrates were tested with different probe molecules. The as-prepared substrates allowed us to detect a minimum concentration of 0.1 ppm in the case of thiram, 1 ppm in the case of thiabendazole (TBZ), 1.6 ppb in the case of methylene blue (MB), and 1.8 ppb in case of Nile blue (NB). All these were achieved using a simple, field-deployable, portable Raman spectrometer. Additionally, the optimized SERS substrate demonstrated ∼21 times higher SERS enhancement than the Au nanostar embedded plain Si substrate. Furthermore, the optimized SERS platform was utilized to detect a mixture of dyes (MB + NB) and pesticides (thiram + TBZ). The possible reasons for the observed additional enhancement are elucidated.

Persulfates to degrade a mixture of dyes (rhodamine B, methylene blue) in the presence of glucose and visible light

Persulfates to degrade a mixture of dyes (rhodamine B, methylene blue) in the presence of glucose and visible light