Eosin Concentration Research Articles

Removal of a local antiseptic dye on two solid supports by adsorption

In this research, we studied the adsorption of an Eosin B (EB) dye is a local antiseptic, available in pharmacies in the form of an active preparation on the surface of activated carbon and natural clay. Activated carbon and natural clay were characterized using various physicochemical techniques to determine the crystalline structures of the two adsorbents by DRX, and the chemical bonds by FTIR analysis, and finally, to know the maximum absorbance λmax of the dye by UV-Visible analysis. The effects of various experimental parameters, such as the effect of adsorbent mass, the initial concentration of eosin B is 1.610-4 molL-1, the contact time is 24 hours, and the pH 7 ~ 9, were studied. The removal of the dye increases with the decrease of the initial concentration of Eosin B (EB) and the contact time of the solution. The percentage of Eosin B (EB) removal increases accordingly, which arrives at 80% for activated carbon and 92% for natural clay. Langmuir and Freundlich adsorption models were used for the adsorption equilibrium descriptions. The data was very well corrected with these models. Monolayer adsorption capacities were equal to 50 mgg-1 at pH 8.3 and 25°C. Adsorption measurements show that the adsorption process is very fast and physical in nature.

Singlet oxygen release due to different concentrations of photosensitizer

Photodynamic therapy is a technique that consists of activating a Photosensitizing Agent (PS) to form reactive oxygen species, which are important for antimicrobial action. This research aimed to carry out laboratory tests to measure singlet oxygenand superoxide radicals release as a function of different formulations and concentrations of methylene blue (MB), eosin Y (EY) and fluorescein (FL) dyes, and to compare their photodynamic efficiency. Solutions containing these compounds in a MIX solvent (glycerol, ethanol and water) irradiated with low power laser (λ= 660 nm) were analyzed. The production of singlet oxygen (1O2) was photometrically evaluated through the consumption rate of 1-3 diphenylisobenzofuran (DPBF), a 1O2 sequestering substance. Statistical analyses applied were the ANOVA and Duncan's complementary test using the Statistical Package for Social Sciences (SPSS) software. MB had greater photodynamic activity, as it presented higher values for the decrease in DPBF for the three concentrations evaluated. The mean concentration was 89.9% at 150 µM, 87.6% and 2.9 at 15 µM, and 77.3% and 2.5 at 1.5 µM. EY and FL presented similar results, with no significant difference between the concentrations. The MB at 150 µM expressed greater production of 1O2, which suggests a greater antimicrobial effect and highlights its relevancecompared to the other dyes.

Efficient heterogeneous photodegradation of Eosin Y by oxidized pyrite using the photo-Fenton process

Eosin Y as a common dye is often used for cotton, silk and other materials. However, Eosin Y is highly toxic and difficult to degrade. Typically, 20% is lost during the printing and dyeing process to produce organic dye wastewater, which can cause serious harm to the environment and human health. Current treatment methods do not satisfy the dual requirements of environmental protection and cost. Pyrite (FeS2) is the most common sulfide gangue mineral and displays excellent photoelectric properties. We chose pyrite as a promising photocatalyst to degrade organic dye wastewater because of its Fe(Ⅱ) and Fe(III) components, which participate in the photo-Fenton reaction. In this study, we use a photocatalytic reaction device incorporating naturally oxidized pyrite as a photocatalytic material to degrade Eosin Y. More than 90% degradation was achieved, when either white or green light was used as the light source over 3 h, in the pH range was 6–8, with an initial concentration of Eosin Y of 10 mg/L. Surprisingly, even if the addition of the pyrite sample is very low, it can still be recycled. The reaction mechanism was explored by composition analysis, scanning electron microscopy-energy dispersive spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance and radical trapping experiments. This study suggests a novel method use for the high-value utilization of sulfide tailings.

Systematic optimization of visible light-induced crosslinking conditions of gelatin methacryloyl (GelMA)

Gelatin methacryloyl (GelMA) is one of the most widely used photo-crosslinkable biopolymers in tissue engineering. In in presence of an appropriate photoinitiator, the light activation triggers the crosslinking process, which provides shape fidelity and stability at physiological temperature. Although ultraviolet (UV) has been extensively explored for photo-crosslinking, its application has been linked to numerous biosafety concerns, originated from UV phototoxicity. Eosin Y, in combination with TEOA and VC, is a biosafe photoinitiation system that can be activated via visible light instead of UV and bypasses those biosafety concerns; however, the crosslinking system needs fine-tuning and optimization. In order to systematically optimize the crosslinking conditions, we herein independently varied the concentrations of Eosin Y [(EY)], triethanolamine (TEOA), vinyl caprolactam (VC), GelMA precursor, and crosslinking times and assessed the effect of those parameters on the properties the hydrogel. Our data showed that except EY, which exhibited an optimal concentration (~ 0.05 mM), increasing [TEOA], [VA], [GelMA], or crosslinking time improved mechanical (tensile strength/modulus and compressive modulus), adhesion (lap shear strength), swelling, biodegradation properties of the hydrogel. However, increasing the concentrations of crosslinking reagents ([TEOA], [VA], [GelMA]) reduced cell viability in 3-dimensional (3D) cell culture. This study enabled us to optimize the crosslinking conditions to improve the properties of the GelMA hydrogel and to generate a library of hydrogels with defined properties essential for different biomedical applications.

Dual Photoredox Catalysis Strategy for Enhanced Photopolymerization-Based Colorimetric Biodetection.

Catalytic redox reactions have been employed to enhance colorimetric biodetection signals in point-of-care diagnostic tests, while their time-sensitive visual readouts may increase the risk of false results. To address this issue, we developed a dual photocatalyst signal amplification strategy that can be controlled by a fixed light dose, achieving time-independent colorimetric biodetection in paper-based tests. In this method, target-associated methylene blue (MB+) photocatalytically amplifies the concentration of eosin Y by oxidizing deactivated eosin Y (EYH3-) under red light, followed by photopolymerization with eosin Y autocatalysis under green light to generate visible hydrogels. Using the insights from mechanistic studies on MB+-sensitized photo-oxidation of EYH3-, we improved the photocatalytic efficiency of MB+ by suppressing its degradation. Lastly, we characterized 100- to 500-fold enhancement in sensitivity obtained from MB+-specific eosin Y amplification, highlighting the advantages of using dual photocatalyst signal amplification.

Assessment of cyto-nephrotoxicity and growth performance in Labeo rohita induced by fluorescein dye Y and B

The cyto-nephrotoxicity in fishes induced by dyes is a global issue. Fluorescein dye has a wide range of applications in industry and biological laboratories. In vivo experiment was planned to assess the sublethal effects of Fluorescein dye, Eosin Y, and Eosin B in Labeo rohita. This freshwater fish was exposed to increasing concentrations (0.0011, 0.0023, and 0.0047 mg/L) of both dyes in the aquarium for definite time intervals. A dye-free trial was set as a control. Fish was anesthetized and dissected by cutting on the ventral side to remove a kidney. Cyto-nephrotoxicity was detected through histopathology. The fish's significant mortality was observed when exposed to 0.0023 mg/L (LC50) and 0.0047 mg/L concentration of Eosin Y dye. These trial groups showed many kidney tissues alterations such as glomerular, tubular epithelial cell's degeneration, a reduced lumen of tubules, vacuolation, absence of bowmen's space, necrosis, glomerulonephritis with increased per tubular space, shrinking of the glomerulus, congestion, clogging, and degeneration of tubules. Eosin B showed less mortality and tissue damage, including glomerular contraction and increased space between glomerulus and capsule. ANOVA showed a highly significant reduction in weight gain of fish at different treatments levels of Eosin Y, but less or none in the case of Eosin B. Increase in fish weight was found to be 66.3 ± 0.38 g when exposed to Eosin Y at 0.0047 mg/L, but it was 69.05 ± 0.63 g when exposed to Eosin B while it was almost identical 69.2 ± 0.23 g for both dye-free trial groups. The pair-wise comparison showed that exposure of the Eosin Y at treatment level 0.0047 mg/L was found to be highly toxic for the kidneys of Labeo rohita. Although both classes of dye are cytotoxic at small concentrations, Eosin Y is acute cyto-nephrotoxic and was found to be involved in growth retardation. To prevent society from fatal consequences, usage of dyes having acute toxicity must be banned or switched to alternates having no effects.

Dye-sensitized solar cell using Eosin Y dye in various concentrations

Abstract This work investigated the effect of various concentrations of Eosin Y dye on the performance of the Dye-sensitized solar cell (DSSC). Distinct concentrations like 10 mg, 20 mg and 30 mg of Eosin Y Dye were prepared for the construction of DSSC. For preparation of photoanode, Titanium dioxide nanoparticles were used to prepare paste, which was deposited on fluorine doped tin oxide (FTO) glass substrate by Doctor blade technique. Absorption spectra of the dyes were taken, and the photovoltaic performance was measured for the fabricated cells. The highest efficiency is obtained by the cell with 10 mg of Eosin Y which is 0.39%. The conversion efficiency of the cells with 20 mg and 30 mg of Eosin Y are 0.007% and 0.0015% respectively.

Effect of curing beam intensity and photoinitiator concentration on the geometrical features and optical transmission of light induced polymer waveguides

Self-written polymer wave guide was constructed between two single mode fibers by photopolymerization using monochromatic laser beam and incoherent light source. Geometrical and optical properties of polymer waveguides have been investigated by changing curing beam power and photoinitiator concentration. For longer bridges beyond 500 µm some surface degradation appeared which caused extra optical loss. We also compared characteristics of two bridges when curing beam power for the second one was reduced from 12.8 µW to 6.4 µW, maintaining all the other fabrication parameters similar. Illumination with high power and longer exposure time leads to a thick waveguide which is wider than the core of the fibers, whereas illumination with reduced beam power and shorter exposure time results in thin bridge with considerable mode mismatching with fibers. Thicker bridge has insertion loss of about 0.4 dB but it is about 2.7 dB for the thinner one. Regarding the effect of photoinitiator density, three different monomer systems were studied. Polymer bridges associated with Eosin concentration 0.5 wt% present optimum surface morphology and optical transmission.

Dual function of Eosin Y in miniemulsion polymerization: Stabilizer and FRET acceptor

Recent studies have shown that water-soluble fluorescent dyes can be used as miniemulsion stabilizers to avoid a series of deficiencies in traditional stabilizers. However, visual means to demonstrate the stabilizing performance of water-soluble dyes are still scarce. In this study, the principle of fluorescence resonance energy transfer (FRET) is combined with dual emission of fluorescent polystyrene nanoparticles prepared by miniemulsion polymerization. For this purpose, 4-(1,2,2-triphenylethyl) phenylundecene-10-enoate (TPE-Aly) was employed as aggregation induced emission (AIE) dye and donor and Eosin Y as acceptor and stabilizer. The polymer molecular weight, particle size and size distribution of the nanoparticles were optimized by regulating the amount of Eosin Y and ultrasonication time, respectively. The average number of Eosin Y molecules per nanoparticle was firstly estimated by combining dialysis and Lambert-Beer law. FRET between TPE-Aly and Eosin Y indicates the presence of Eosin Y on the surface of the polymer nanoparticles. With increasing concentration of Eosin Y, the as-prepared dual-emission nanoparticles display a decreasing particle size along with an enhancing FRET efficiency. Moreover, various stability tests show that Eosin Y can be used as an excellent stabilizer for miniemulsion polymerization and has broad application prospects in the field of functional materials research.

Quantitative Analysis and Correction of Temperature Effects on Fluorescent Tracer Concentration Measurement

To ensure an accurate evaluation of pesticide spray application efficiency and pesticide mixture uniformity, reliable and accurate measurements of fluorescence concentrations in spray solutions are critical. The objectives of this research were to examine the effects of solution temperature on measured concentrations of fluorescent tracers as the simulated pesticides and to develop models to correct the deviation of measurements caused by temperature variations. Fluorescent tracers (Brilliant Sulfaflavine (BSF), Eosin, Fluorescein sodium salt) were selected for tests with the solution temperatures ranging from 10.0 °C to 45.0 °C. The results showed that the measured concentrations of BSF decreased as the solution temperature increased, and the decrement rate was high at the beginning and then slowed down and tended to become constant. In contrast, the concentrations of Eosin decreased slowly at the beginning and then noticeably increased as temperatures increased. On the other hand, the concentrations of Fluorescein sodium salt had little variations with its solution temperature. To ensure the measurement accuracy, correction models were developed using the response surface methodology to numerically correct the measured concentration errors due to variations with the solution temperature. Corrected concentrations using the models agreed well with the actual concentrations, and the overall relative errors were reduced from 42.36% to 2.91% for BSF, 11.72% to 1.55% for Eosin, and 2.68% to 1.17% for Fluorescein sodium salt. Thus, this approach can be used to improve pesticide sprayer performances by accurately quantifying droplet deposits on target crops and off-target areas.

Investigation of the Synergistic Effect of Sonolysis and Photocatalysis of Titanium Dioxide for Organic Dye Degradation

Herein, we report the effect of sonoluminescence and an initial dye concentration on the sonophotocatalysis of TiO2 for the degradation of eosin B, a textile dye. We first investigated the light illuminated during ultrasound irradiation (sonoluminescence) by photographic images, a radical indicator (luminol), and photoluminescence spectra of the detection range of 300–1050 nm. Next, we examined the synergistic effect of sonolysis on photocatalysis by comparing the dye degradation of sonophotocatalysis to that of individual contributions of sonolysis and photocatalysis. Since it was found that the synergist effect is highly engaged with a dye concentration and sonication power, we conducted the comparison test in different concentrations of eosin B (5 and 20 mg/L) and ultrasound powers (35.4, 106.1, and 176.8 W/cm2). When the concentration of dyes was low, negative synergistic effects were found at all ultrasound powers, whereas at the high concentration, positive synergistic effects were observed at high ultrasound power. This difference in synergistic effects was explained by the influence of ultrasound on dynamics of dye adsorption on the TiO2 surface.

Application of Organo-Magadiites for the Removal of Eosin Dye from Aqueous Solutions: Thermal Treatment and Regeneration.

Na-magadiite exchanged with cetyl-trimethylammonium cations provided organophilic silicate materials that allowed for the effective removal of the acidic dye “eosin”. The organic cations were intercalated into the interlayer spacing of the layered silicate via an exchange reaction between the organic cations from their bromide salt and the solid Na-magadiite at room temperature. Different techniques were used to characterize the effect of the initial concentration of the surfactant on the structure of the organo-magadiites. The C, H, and N analysis indicated that a maximum of organic cations of 0.97 mmol/g was achieved and was accompanied by an expansion of the basal spacing of 3.08 nm, with a tilted angle of 59° to the silicate layers. The conformation of the organic surfactants was probed using solid-state 13C, finding mainly the trans conformation similar to that of the starting cetyl trimethylammonium bromide salt (C16TMABr). Thermal gravimetric analysis was carried out to study the thermal stability of the resulting organo-magadiites. The intercalated surfactants started to decompose at 200 °C, with a mass loss percentage of 8% to 25%, depending on the initial loading of the surfactant, and was accompanied by a decrease of the basal spacing from 3.16 nm to 2.51 nm, as deduced from the in situ X-ray diffraction studies. At temperatures below 220 °C, an expansion of the basal spacing from 3.15 to 3.34 nm occurred. These materials were used as a removal agent for the anionic dye eosin. The maximum amount of the dye removed was related to the organic cation content and to the initial concentration of eosin, with an improvement from 2.5 mg/g to 80.65 mg/g. This value decreased when the organo-magadiite was preheated at temperatures above 200 °C. The regeneration tests indicated that an 85% removal efficiency was maintained after six cycles of use for the organo-magadiite using Ci of 200 mg/L.

The Impact of Continuous Oxygen Flux in a Thin Film Photopolymerization Reaction with Peroxy‐Mediated Regeneration of Initiator

Eosin, a photosensitizer dye that can exist in multiple oxidation states, has been shown to initiate visible‐light photopolymerizations of acrylates in open air when used in combination with tertiary amines. The exact mechanism behind this reactivity with micromolar concentrations of eosin in aqueous monomer solutions initially containing millimolar concentrations of oxygen has not been conclusively established, although pathways for regeneration of eosin in the presence of oxygen certainly play a role. In this work, a reaction–diffusion model incorporating a peroxy‐mediated eosin‐regeneration mechanism is built to explore the effects of oxygen diffusing into the system as the light‐activated reaction proceeds. An oxygen concentration‐dependent flux boundary condition is used to model the continuous replenishment of oxygen at the surface open to air as it is consumed by reaction. The model predicts the formation of a free radical concentration front that initially forms closer to the open surface and gradually moves toward the closed surface, with polymer film thickness increasing and the time required for polymerization to begin decreasing as the initial eosin concentration is increased. These results suggest that oxygen's dual role as both a free radical inhibitor and a precursor of the oxidizing species required for regeneration of eosin brings about interesting spatial variations when the reaction is carried out in a thin film geometry that is exposed to open air. In this case, an assumption of a well‐mixed system is not appropriate and the kinetics of the reaction and conversion as a function of position are likely to depend on the geometry of the system. image

Efficient photocatalytic hydrogen production from water over Pt–Eosin Y catalyst: A systemic study of reaction parameters

A high efficient homogeneous system for hydrogen production from water consisting of Eosin Y as a photosensitizer, methyl viologen (MV2+) as an electron transfer mediator, triethanolamine (TEOA) as a sacrificial electron donor and colloid Pt as a catalyst, has been systemicly studied. The initial system pH and the concentration of Eosin Y have remarkable effects on the rate of hydrogen evolution. The optimal pH and concentration of Eosin Y are 9 and 7.2×10−5M. Triethanolamine (TEOA) as an electron donor, can reductively quench the oxidized Eosin Y and the quenching is well modeled by the Stern–Volmer equation. The optimal concentration of TEOA and the concentration of MV2+ are 0.3M and 3.1×10−4M, respectively. In addition, the role of colloid Pt has been investigated.

Crystal structure and photoelectric conversion properties of eosin Y-adsorbing ZnO films prepared by electroless deposition

Eosin Y-adsorbing ZnO thin films were prepared on substrates by electroless deposition from aqueous solutions containing zinc nitrate, dimethylamine−borane, and eosin Y. The concentration of eosin Y in the solution changed the structure of the deposited ZnO particles on the substrate. In the absence of eosin Y in the solution, the ZnO crystals preferred to grow in the c-axis direction. In the presence of eosin Y in the solution, the orientation of the ZnO was in the a-axis direction. As the eosin Y concentration increased, the size of the ZnO crystallites decreased and they became aggregated due to a strong interaction between the eosin Y and the (0002) plane of the ZnO, and consequently, the film resistance increased due to their boundary. The electron injection efficiency increased due to the strong interaction although the electron transfer efficiency decreased. The ZnO crystallite size, eosin Y amount, and their interaction increased the energy conversion efficiency.

A quantitative analysis of peroxy-mediated cyclic regeneration of eosin under oxygen-rich photopolymerization conditions

Eosin, a photoreducible xanthene, reacts with tertiary amines and initiates the free radical photopolymerization of aqueous solutions of acrylate monomers. This reaction proceeds even in the presence of a large excess (∼1000×) of inhibiting oxygen via a mechanism that has not been established conclusively. This chemistry has proven useful in the area of biosensing, where the formation of a hydrogel on the time scale of seconds serves as a macroscopic, amplified signal that can be connected to molecular recognition events. In this work, we built a kinetic model to quantitatively explore a mechanism in which eosin is regenerated through the reaction of eosin-based radicals with peroxy-radicals formed from oxygen-inhibition reactions. To determine whether the predictions of this model are consistent with conversion profiles measured using real-time FTIR, we refrained from fitting rate constants or other unknown parameters associated with individual steps in the mechanism to the conversion profile. Rather, we considered physical upper bounds and performed sensitivity analyses spanning several orders of magnitude to predict the reactivity of the system. We explored the effects of the peroxy-mediated regeneration rate constant, kregen, and the initial eosin concentration on the irradiation time that is required to reach a CC bond conversion of 0.2 (t0.2). At this CC bond conversion, the aqueous monomer solutions studied herein have become hydrogels. The predictions of the model capture several trends that we have observed experimentally. However, even when the rate constants associated with eosin regeneration via reaction with peroxy-species are set at the physical upper bounds, the values of t0.2 predicted by the model are much larger than those that we observed experimentally. The results presented herein motivate and provide a framework for future work to more fully elucidate the mechanism of this interesting and useful photopolymerization reaction.

Synthesis and characterization of CdS/CuAl2O4 core–shell: application to photocatalytic eosin degradation

The advantages of the hetero-junction CdS/CuAl2O4 for the photocatalytic eosin degradation are reported. Composite semiconductors are elaborated by co-precipitation of CdS on the spinel CuAl2O4 giving a core–shell structure with a uniform dispersion and intimate contact of the spinel nanoparticles inside the hexagonal CdS. The Mott–Schottky plots (C−2–V) of both materials show linear behaviors from which flat band potentials are determined. The photoactivity increases with increasing the mass of the sensitizer CdS and the best performance is achieved on CdS/CuAl2O4 (85 %/15 %). The pH has a strong influence on the degradation and the photoactivity peaks at pH 7.78. The dark adsorption eosin is weak (~4 %), hence the change in the eosin concentration is attributed to the photocatalytic process. The degradation follows a zero-order kinetic with a rate constant of 5.2 × 10−8 mol L−1 mn−1 while that of the photolysis is seven times lower (0.75 × 10−8 mol L−1 mn−1).

Study on the fluorescence resonance energy transfer between CdS quantum dots and Eosin Y.

Water-soluble CdS quantum dots (QDs) were prepared using mercaptoacetic acid (TGA) as the stabilizer in an aqueous system. A fluorescence resonance energy transfer (FRET) system was constructed between water-soluble CdS QDs (donor) and Eosin Y (acceptor). Several factors that impacted the fluorescence spectra of the FRET system, such as pH (3.05-10.10), concentration of Eosin Y (2-80 mg/L) and concentration of CdS QDs (2-80 mg/L), were investigated and refined. Donor-to-acceptor ratios, the energy transfer efficiency (E) and the distance (r) between CdS QDs and Eosin Y were obtained. The results showed that a FRET system could be established between water-soluble CdS QDs and Eosin Y at pH 5.0; donor-to-acceptor ratios demonstrated a 1: 8 proportion of complexes; the energy transfer efficiency (E) and the distance (r) between the QDs and Eosin Y were 20.07% and 4.36 nm,respectively.

The Study on the Influential Factors of Photocatalytic Performance of Eosin-Sensitized TiO<sub>2</sub> Nanoparticles

The photocatalytic activity of eosin-sensitized TiO2 nanoparticles on photocatalytic degradation rate (PDR) of methyl orange under sunlight irradiation was studied. The influential factors on the degradation, such as eosin concentration, TiO2 dosage, sensitization time and sensitization temperature were also investigated. The results show that: The performance of TiO2 nanoparticles for PDR of methyl orange has been improved obviously for eosin sensitizing. The PDR of methyl orange reached 45.28% under the conditions of eosin concentration of 20mg/L, TiO2 dosage of 0.5000g/L, sensitization time of 24h and sensitization temperature of 20°C.

Preparation of Dye-Adsorbing ZnO Thin Films by Electroless Deposition and Their Photoelectrochemical Properties

Dye-adsorbing ZnO thin films were prepared on ITO films by electroless deposition. The films were formed in an aqueous solution containing zinc nitrate, dimethylamine-borane, and eosin Y at 328 K. The film thickness was 1.2-2.0 μm. Thinner and larger-plane hexagonal columns were produced from the solution containing a higher concentration of eosin Y. A photocurrent was observed in the electrodes containing such ZnO films during light irradiation. The photoelectrochemical performance of the film was improved by increasing the concentration of eosin Y because of increases in the amount of absorbed photons and the electronic conductivity of ZnO.