Utilization of Corn Cob and TiO2 Photocatalyst Thin Films for Dyes Removal.

PubMed

Gan, Hui-Yee; Leow, Li-Eau; Ong, Siew-Teng

2017-01-01

The effectiveness of using TiO2 and corn cob films to remove Malachite Green oxalate (MG) and Acid Yellow 17 (AY 17) from binary dye solution was studied. The immobilization method in this study can avoid the filtration step which is not suited for practical applications. Batch studies were performed under different experimental conditions and the parameters studied involved initial pH of dye solution, initial dye concentration and contact time and reusability. The equilibrium data of MG and AY 17 conform to Freundlich and Langmuir isotherm model, respectively. The percentage removal of MG remained high after four sorption cycles, however for AY 17, a greater reduction was observed. The removal of both dyes were optimized and modeled via Plackett- Burman design (PB) and Response Surface Methodology (RSM). IR spectrum and surface conditions analyses were carried out using fourier-transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM) and atomic force microscope (AFM), respectively.

Time-resolved fluorescence polarization spectroscopy of visible and near infrared dyes in picosecond dynamics

NASA Astrophysics Data System (ADS)

Pu, Yang; Alfano, Robert R.

2015-03-01

Near-infrared (NIR) dyes absorb and emit light within the range from 700 to 900 nm have several benefits in biological studies for one- and/or two-photon excitation for deeper penetration of tissues. These molecules undergo vibrational and rotational motion in the relaxation of the excited electronic states, Due to the less than ideal anisotropy behavior of NIR dyes stemming from the fluorophores elongated structures and short fluorescence lifetime in picosecond range, no significant efforts have been made to recognize the theory of these dyes in time-resolved polarization dynamics. In this study, the depolarization of the fluorescence due to emission from rotational deactivation in solution will be measured with the excitation of a linearly polarized femtosecond laser pulse and a streak camera. The theory, experiment and application of the ultrafast fluorescence polarization dynamics and anisotropy are illustrated with examples of two of the most important medical based dyes. One is NIR dye, namely Indocyanine Green (ICG) and is compared with Fluorescein which is in visible range with much longer lifetime. A set of first-order linear differential equations was developed to model fluorescence polarization dynamics of NIR dye in picosecond range. Using this model, the important parameters of ultrafast polarization spectroscopy were identified: risetime, initial time, fluorescence lifetime, and rotation times.

A novel biosorbent for dye removal: extracellular polymeric substance (EPS) of Proteus mirabilis TJ-1.

PubMed

Zhang, Zhiqiang; Xia, Siqing; Wang, Xuejiang; Yang, Aming; Xu, Bin; Chen, Ling; Zhu, Zhiliang; Zhao, Jianfu; Jaffrezic-Renault, Nicole; Leonard, Didier

2009-04-15

This paper deals with the extracellular polymeric substance (EPS) of Proteus mirabilis TJ-1 used as a novel biosorbent to remove dye from aqueous solution in batch systems. As a widely used and hazardous dye, basic blue 54 (BB54) was chosen as the model dye to examine the adsorption performance of the EPS. The effects of pH, initial dye concentration, contact time and temperature on the sorption of BB54 to the EPS were examined. At various initial dye concentrations (50-400 mg/L), the batch sorption equilibrium can be obtained in only 5 min. Kinetic studies suggested that the sorption followed the internal transport mechanism. According to the Langmuir model, the maximum BB54 uptake of 2.005 g/g was obtained. Chemical analysis of the EPS indicated the presence of protein (30.9%, w/w) and acid polysaccharide (63.1%, w/w). Scanning electron microscopy (SEM) images showed that the EPS with a crystal-linear structure was whole enwrapped by adsorbed dye molecules. FTIR spectrum result revealed the presence of adsorbing groups such as carboxyl, hydroxyl and amino groups in the EPS. High-molecular weight of the EPS with more binding-sites and stronger van der Waals forces together with its specific construct leads to the excellent performance of dye adsorption. The EPS shows potential board application as a biosorbent for both environmental protection and dye recovery.

Biosorption of Azo dyes by spent Rhizopus arrhizus biomass

NASA Astrophysics Data System (ADS)

Salvi, Neeta A.; Chattopadhyay, S.

2017-10-01

In the present study, spent Rhizopus arrhizus biomass was used for the removal of six azo dyes from aqueous solutions. The dye removal capacity of the biomass was evaluated by conducting batch tests as a function of contact time, biomass dosage, pH and initial dye concentrations. The pseudo-second-order kinetic model fitted well with the experimental data with correlation coefficients greater than 0.999, suggesting that chemisorptions might be the rate limiting step. The equilibrium sorption data showed good fit to the Langmuir isotherm model. Among the six dyes tested, the maximum monolayer adsorption capacity for fast red A and metanil yellow was found to be 108.8 and 128.5 mg/g, respectively. These encouraging results suggest that dead Rhizopus arrhizus biomass could be a potential biomaterial for the removal of azo dyes from aqueous dye solution.

Aberration corrected STEM to study an ancient hair dyeing formula

NASA Astrophysics Data System (ADS)

Patriarche, G.; Van Elslande, E.; Castaing, J.; Walter, P.

2014-05-01

Lead-based chemistry was initiated in ancient Egypt for cosmetic preparation more than 4000 years ago. Here, we study a hair-dyeing recipe using lead salts described in text since Greco-Roman times. We report direct evidence about the shape and distribution of PbS nanocrystals that form within the hair during blackening.

Adsorption of malachite green dye from aqueous solution on the bamboo leaf ash

NASA Astrophysics Data System (ADS)

Kuntari, Priwidyanjati, Dessyntha Anggiani

2017-12-01

Bamboo leaf ash has been developed as an adsorbent material for removal malachite green from aqueous solution. Adsorption parameters have studied are contact time and initial pH. The effect of contact time and pH were examined in the batch adsorption processes. The physicochemical characters of bamboo leaf ash were investigated by using X-Ray Diffraction (XRD) and FT-IR spectroscopy. Malachite green concentration was determined by UV-Vis spectrophotometer. FT-IR spectrogram of bamboo leaf ash shows that typical fingerprint of adsorbent material with Si-O-Si or Al-O-Al group. The X-ray diffractograms of bamboo leaf ash show that adsorbent material has a highly amorphous nature. The percentage of adsorption was showed raised with increasing contact time. The optimum removal of malachite green when the initial dye concentration, initial pH, weight of adsorbent and contact time was 20 mg/L, 7, 0.25 g and 75 minutes respectively.

Studies on the use of power ultrasound in leather dyeing.

PubMed

Sivakumar, Venkatasubramanian; Rao, Paruchuri Gangadhar

2003-03-01

Uses of power ultrasound for acceleration/performing the chemical as well as physical processes are gaining importance. In conventional leather processing, the diffusion of chemicals through the pores of the skin/hide is achieved by the mechanical agitation caused by the paddle or drumming action. In this work, the use of power ultrasound in the dyeing of leather has been studied with the aim to improve the exhaustion of dye for a given processing time, to reduce the dyeing time and to improve the quality of dyed leather. The effect of power ultrasound in the dyeing of full chrome cow crust leather in a stationary condition is compared with dyeing in the absence of ultrasound as a control experiment both in a stationary as well as conventional drumming condition. An ultrasonic cleaner (150 W and 33 kHz) was used for the experiments. Actual power dissipated into the system was calculated from the calorimetric measurement. Experiments were carried out with variation in type of dye, amount of dye offer, temperature and time. The results show that there is a significant improvement in the percentage exhaustion of dye due to the presence of ultrasound, when compared to dyeing in absence of ultrasound. Experiments on equilibrium dye uptake carried out with or without ultrasound suggest that ultrasound help to improve the kinetics of leather dyeing. The results indicate that leathers dyed in presence of ultrasound have higher colour values, better dye penetration and fastness properties compared to control leathers. The physical testing results show that strength properties of the dyed leathers are not affected due to the application of ultrasound under the given process conditions. Apparent diffusion coefficient during the initial stage of dyeing process, both in presence and in absence of ultrasound was calculated. The values show that ultrasound helps in improving the apparent diffusion coefficient more for the difficult dyeing conditions such as in the case of metal-complex dyes having bigger aggregate size compared to less difficult dyeing conditions.

Microcolumn studies of dye adsorption onto manganese oxides modified diatomite.

PubMed

Al-Ghouti, M A; Khraisheh, M A M; Ahmad, M N; Allen, S J

2007-07-19

The method described here cannot fully replace the analysis of large columns by small test columns (microcolumns). The procedure, however, is suitable for speeding up the determination of adsorption parameters of dye onto the adsorbent and for speeding up the initial screening of a large adsorbent collection that can be tedious if a several adsorbents and adsorption conditions must be tested. The performance of methylene blue (MB), a basic dye, Cibacron reactive black (RB) and Cibacron reactive yellow (RY) was predicted in this way and the influence of initial dye concentration and other adsorption conditions on the adsorption behaviour were demonstrated. On the basis of the experimental results, it can be concluded that the adsorption of RY onto manganese oxides modified diatomite (MOMD) exhibited a characteristic "S" shape and can be simulated effectively by the Thomas model. It is shown that the adsorption capacity increased as the initial dye concentration increased. The increase in the dye uptake capacity with the increase of the adsorbent mass in the column was due to the increase in the surface area of adsorbent, which provided more binding sites for the adsorption. It is shown that the use of high flow rates reduced the time that RY in the solution is in contact with the MOMD, thus allowing less time for adsorption to occur, leading to an early breakthrough of RY. A rapid decrease in the column adsorption capacity with an increase in particle size with an average 56% reduction in capacity resulting from an increase in the particle size from 106-250 microm to 250-500 microm. The experimental data correlated well with calculated data using the Thomas equation and the bed depth-service time (BDST) equation. Therefore, it might be concluded that the Thomas equation and the BDST equations can produce accurate predication for variation of dye concentration, mass of the adsorbent, flow rate and particle size. In general, the values of adsorption isotherm capacity obtained in a batch system show the maximum values and are considerably higher than those obtained in a fixed-bed.

Biosorption of textile dye reactive blue 221 by capia pepper (Capsicum annuum L.) seeds.

PubMed

Gürel, Levent

2017-04-01

Peppers are very important foodstuffs in the world for direct and indirect consumption, so they are extensively used. The seeds of these peppers are waste materials that are disposed of from houses and factories. To evaluate the performance of this biomass in the treatment of wastewaters, a study was conducted to remove a textile dye, reactive blue 221, which is commercially used in textile mills. Raw seed materials were used without any pre-treatment. The effects of contact time, initial concentration of dye, pH and dose of biosorbent were studied to determine the optimum conditions for this biomass on color removal from wastewaters. The optimum pH value for dye biosorption was found to be 2.0. At an initial dye concentration of 217 mg L -1 , treatment efficiency and biosorption capacity were 96.7% and 95.35 mg g -1 , respectively. A maximum biosorption capacity of 142.86 mg g -1 was also obtained. Equilibrium biosorption of dye by capia seeds was well described by the Langmuir isotherm with a correlation coefficient above 99%. The biosorption process was also successfully explained with the pseudo-second order kinetic model. This biomass was found to be effective in terms of textile dye removal from aqueous solutions.

Application of acidic treated pumice as an adsorbent for the removal of azo dye from aqueous solutions: kinetic, equilibrium and thermodynamic studies

PubMed Central

2012-01-01

Colored effluents are one of the important environment pollution sources since they contain unused dye compounds which are toxic and less-biodegradable. In this work removal of Acid Red 14 and Acid Red 18 azo dyes was investigated by acidic treated pumice stone as an efficient adsorbent at various experimental conditions. Removal of dye increased with increase in contact time and initial dye concentration, while decreased for increment in solution temperature and pH. Results of the equilibrium study showed that the removal of AR14 and AR18 followed Freundlich (r2>0.99) and Langmuir (r2>0.99) isotherm models. Maximum sorption capacities were 3.1 and 29.7 mg/g for AR 14 and AR18, namely significantly higher than those reported in the literature, even for activated carbon. Fitting of experimental data onto kinetic models showed the relevance of the pseudo-second order (r2>0.99) and intra-particle diffusion (r2>0.98) models for AR14 and AR18, respectively. For both dyes, the values of external mass transfer coefficient decreased for increasing initial dye concentrations, showing increasing external mass transfer resistance at solid/liquid layer. Desorption experiments confirmed the relevance of pumice stone for dye removal, since the pH regeneration method showed 86% and 89% regeneration for AR14 and AR18, respectively. PMID:23369579

The effects of chemical coagulants on the decolorization of dyes by electrocoagulation using response surface methodology (RSM)

NASA Astrophysics Data System (ADS)

Butler, Erick B.; Hung, Yung-Tse; Mulamba, Oliver

2017-09-01

This study assessed the efficiency of electrocoagulation (ECF) coupled with an addition of chemical coagulant to decolorize textile dye. Tests were conducted using Box Behnken methodology to vary six parameters: dye type, weight, coagulant type, dose, initial pH and current density. The combination of electrocoagulation and chemical coagulation was able to decolorize dye up to 99.42 % in 30 min of treatment time which is remarkably shorter in comparison with using conventional chemical coagulation. High color removal was found to be contingent upon the dye type and current density, along with the interactions between the current density and the coagulant dose. The addition of chemical coagulants did enhanced treatment efficiency.

Formic acid enhanced effective degradation of methyl orange dye in aqueous solutions under UV-Vis irradiation.

PubMed

Wang, Jingjing; Bai, Renbi

2016-09-15

Developing efficient technologies to treat recalcitrant organic dye wastewater has long been of great research and practical interest. In this study, a small molecule, formic acid (FA), was applied as a process enhancer for the degradation of methyl orange (MO) dye as a model recalcitrant organic pollutant in aqueous solutions under the condition of UV-Vis light irradiation and air aeration at the ambient temperature of 25 °C. It was found that the decolouration of the dye solutions can be rapidly achieved, reducing the time, for example, from around 17.6 h without FA to mostly about less than 2 h with the presence of FA. The mineralization rate of MO dye reached as high as 81.8% in 1.5 h in the case of initial MO dye concentration at 25 mg L(-1), which is in contrast to nearly no mineralization of the MO dye for a similar system without the FA added. The study revealed that the generation of the H2O2 species in the system was enhanced and the produced OH radicals effectively contributed to the degradation of the MO dye. Process parameters such as the initial concentration of MO dye, FA dosage and solution pH were all found to have some effect on the degradation efficiency under the same condition of UV-Vis light irradiation and air aeration. The MO dye degradation performance was found to follow a first-order reaction rate to the MO dye concentration in most cases and there existed a positive correlation between the reaction rate constant and the initial FA concentration. Compared to the traditional H2O2/UV-Vis oxidation system, the use of FA as a process-enhancing agent can have the advantages of low cost, easy availability, and safe to use. The study hence demonstrates a promising approach to use a readily available small molecule of FA to enhance the degradation of recalcitrant organic pollutants, such as MO dye, especially for their pre-treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced removal of hazardous dye form aqueous solutions and real textile wastewater using bifunctional chitin/lignin biosorbent.

PubMed

Wawrzkiewicz, Monika; Bartczak, Przemysław; Jesionowski, Teofil

2017-06-01

A new biomaterial based on chitin and lignin was prepared and applied for the removal of hazardous dye C.I. Direct Blue 71 (DB71) from aqueous solutions and wastewaters. The dye sorption on the chitin/lignin biosorbent (Ch/L) was examined depending on the initial dye concentration (50-200mg/L), phase contact time (1-1440min), kind of auxiliaries (NaCl, Na 2 SO 4 , anionic surfactant SDS) and their concentrations (1-20g/L salts, 0.1-0.75g/L SDS), initial solution pH as well as temperature (20-50°C). The equilibrium and kinetic characteristics of C.I. Direct Blue 71 uptake by chitin/lignin followed by the Freundlich isotherm model and the pseudo-second order model rather than the Langmuir, Tempkin models, and pseudo-first order model. C.I. Direct Blue 71 adsorption on chitin/lignin was spontaneous (-2.86 to -8.14kJ/mol) and endothermic (60.1kJ/mol). The possibilities of dye elution and reuse by means of the batch method were investigated and as follows the chemical reaction is an inseparable sorption mechanism. Purification of wastewaters containing direct dyes was made with 91% efficiency after 1h of phase contact time. For comparison, data obtained or obtained results in the DB71-chitin (Ch) system were also presented. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrafast electron and energy transfer in dye-sensitized iron oxide and oxyhydroxide nanoparticles.

PubMed

Gilbert, Benjamin; Katz, Jordan E; Huse, Nils; Zhang, Xiaoyi; Frandsen, Cathrine; Falcone, Roger W; Waychunas, Glenn A

2013-10-28

An emerging area in chemical science is the study of solid-phase redox reactions using ultrafast time-resolved spectroscopy. We have used molecules of the photoactive dye 2',7'-dichlorofluorescein (DCF) anchored to the surface of iron(III) oxide nanoparticles to create iron(II) surface atoms via photo-initiated interfacial electron transfer. This approach enables time-resolved study of the fate and mobility of electrons within the solid phase. However, complete analysis of the ultrafast processes following dye photoexcitation of the sensitized iron(III) oxide nanoparticles has not been reported. We addressed this topic by performing femtosecond transient absorption (TA) measurements of aqueous suspensions of uncoated and DCF-sensitized iron oxide and oxyhydroxide nanoparticles, and an aqueous iron(III)-dye complex. Following light absorption, excited state relaxation times of the dye of 115-310 fs were found for all samples. Comparison between TA dynamics on uncoated and dye-sensitized hematite nanoparticles revealed the dye de-excitation pathway to consist of a competition between electron and energy transfer to the nanoparticles. We analyzed the TA data for hematite nanoparticles using a four-state model of the dye-sensitized system, finding electron and energy transfer to occur on the same ultrafast timescale. The interfacial electron transfer rates for iron oxides are very close to those previously reported for DCF-sensitized titanium dioxide (for which dye-oxide energy transfer is energetically forbidden) even though the acceptor states are different. Comparison of the alignment of the excited states of the dye and the unoccupied states of these oxides showed that the dye injects into acceptor states of different symmetry (Ti t2gvs. Fe eg).

Adsorption of Congo red dye onto antimicrobial terephthaloyl thiourea cross-linked chitosan hydrogels.

PubMed

El-Harby, Nouf F; Ibrahim, Shaimaa M A; Mohamed, Nadia A

2017-11-01

Adsorption capacity of three antimicrobial terephthaloyl thiourea cross-linked chitosan hydrogels for Congo red dye removal from its aqueous solution has been investigated for the first time in this work. These hydrogels were prepared by reacting chitosan with various amounts of terephthaloyl diisothiocyanate cross-linker. The effect of the hydrogel structural variations and several dye adsorption processing parameters to achieve the best adsorption capacity were investigated. The hydrogels' structural variations were obtained by varying their terephthaloyl thiourea moieties content. The processing variables included initial concentration of the dye solution, temperature and time of exposure to the dye. The adsorption kinetics and isotherms showed that the sorption processes were better fitted by the pseudo-second-order equation and the Langmuir equation, respectively. On the basis of the Langmuir analysis Congo red dye gave the maximum sorption capacity of 44.248 mg/g. The results obtained confirmed that the sorption phenomena are most likely to be controlled by chemisorption process. The adsorption reaction was endothermic and spontaneous according to the calculated results of adsorption thermodynamics.

Spectroscopic properties and amplified spontaneous emission of fluorescein laser dye in ionic liquids as green media

NASA Astrophysics Data System (ADS)

AL-Aqmar, Dalal M.; Abdelkader, H. I.; Abou Kana, Maram T. H.

2015-09-01

The use of ionic liquids (ILs) as milieu materials for laser dyes is a promising field and quite competitive with volatile organic solvents and solid state-dye laser systems. This paper investigates some photo-physical parameters of fluorescein dye incorporated into ionic liquids; 1-Butyl-3-methylimidazolium chloride (BMIM Cl), 1-Butyl-3-methylimidazolium tetrachloroaluminate (BMIM AlCl4) and 1-Butyl-3-methylimidazolium tetrafluoroborate (BMIM BF4) as promising host matrix in addition to ethanol as reference. These parameters are: absorption and emission cross-sections, fluorescence lifetime and quantum yield, in addition to the transition dipole moment, the attenuation length and oscillator strength were also investigated. Lasing characteristics such as amplified spontaneous emission (ASE), the gain, and the photostability of fluorescein laser dye dissolved in different host materials were assessed. The composition and properties of the matrix of ILs were found that it has great interest in optimizing the laser performance and photostability of the investigated laser dye. Under transverse pumping of fluorescein dye by blue laser diode (450 nm) of (400 mW), the initial ASE for dye dissolved in BMIM AlCl4 and ethanol were decreased to 39% and 36% respectively as time progressed 132 min. Relatively high efficiency and high fluorescence quantum yield (11.8% and 0.82% respectively) were obtained with good photostability in case of fluorescein in BMIM BF4 that was decreased to ∼56% of the initial ASE after continuously pumping with 400 mW for 132 min.

Fractional Factorial Design Study on the Performance of GAC-Enhanced Electrocoagulation Process Involved in Color Removal from Dye Solutions.

PubMed

Secula, Marius Sebastian; Cretescu, Igor; Cagnon, Benoit; Manea, Liliana Rozemarie; Stan, Corneliu Sergiu; Breaban, Iuliana Gabriela

2013-07-10

The aim of this study was to determine the effects of main factors and interactions on the color removal performance from dye solutions using the electrocoagulation process enhanced by adsorption on Granular Activated Carbon (GAC). In this study, a mathematical approach was conducted using a two-level fractional factorial design ( FFD ) for a given dye solution. Three textile dyes: Acid Blue 74, Basic Red 1, and Reactive Black 5 were used. Experimental factors used and their respective levels were: current density (2.73 or 27.32 A/m²), initial pH of aqueous dye solution (3 or 9), electrocoagulation time (20 or 180 min), GAC dose (0.1 or 0.5 g/L), support electrolyte (2 or 50 mM), initial dye concentration (0.05 or 0.25 g/L) and current type (Direct Current- DC or Alternative Pulsed Current- APC ). GAC-enhanced electrocoagulation performance was analyzed statistically in terms of removal efficiency, electrical energy, and electrode material consumptions, using modeling polynomial equations. The statistical significance of GAC dose level on the performance of GAC enhanced electrocoagulation and the experimental conditions that favor the process operation of electrocoagulation in APC regime were determined. The local optimal experimental conditions were established using a multi-objective desirability function method.

Fractional Factorial Design Study on the Performance of GAC-Enhanced Electrocoagulation Process Involved in Color Removal from Dye Solutions

PubMed Central

Secula, Marius Sebastian; Cretescu, Igor; Cagnon, Benoit; Manea, Liliana Rozemarie; Stan, Corneliu Sergiu; Breaban, Iuliana Gabriela

2013-01-01

The aim of this study was to determine the effects of main factors and interactions on the color removal performance from dye solutions using the electrocoagulation process enhanced by adsorption on Granular Activated Carbon (GAC). In this study, a mathematical approach was conducted using a two-level fractional factorial design (FFD) for a given dye solution. Three textile dyes: Acid Blue 74, Basic Red 1, and Reactive Black 5 were used. Experimental factors used and their respective levels were: current density (2.73 or 27.32 A/m2), initial pH of aqueous dye solution (3 or 9), electrocoagulation time (20 or 180 min), GAC dose (0.1 or 0.5 g/L), support electrolyte (2 or 50 mM), initial dye concentration (0.05 or 0.25 g/L) and current type (Direct Current—DC or Alternative Pulsed Current—APC). GAC-enhanced electrocoagulation performance was analyzed statistically in terms of removal efficiency, electrical energy, and electrode material consumptions, using modeling polynomial equations. The statistical significance of GAC dose level on the performance of GAC enhanced electrocoagulation and the experimental conditions that favor the process operation of electrocoagulation in APC regime were determined. The local optimal experimental conditions were established using a multi-objective desirability function method. PMID:28811405

Experimental design and response surface modelling for optimization of vat dye from water by nano zero valent iron (NZVI).

PubMed

Arabi, Simin; Sohrabi, Mahmoud Reza

2013-01-01

In this study, NZVI particles was prepared and studied for the removal of vat green 1 dye from aqueous solution. A four-factor central composite design (CCD) combined with response surface modeling (RSM) to evaluate the combined effects of variables as well as optimization was employed for maximizing the dye removal by prepared NZVI based on 30 different experimental data obtained in a batch study. Four independent variables, viz. NZVI dose (0.1-0.9 g/L), pH (1.5-9.5), contact time (20-100 s), and initial dye concentration (10-50 mg/L) were transform to coded values and quadratic model was built to predict the responses. The significant of independent variables and their interactions were tested by the analysis of variance (ANOVA). Adequacy of the model was tested by the correlation between experimental and predicted values of the response and enumeration of prediction errors. The ANOVA results indicated that the proposed model can be used to navigate the design space. Optimization of the variables for maximum adsorption of dye by NZVI particles was performed using quadratic model. The predicted maximum adsorption efficiency (96.97%) under the optimum conditions of the process variables (NZVI dose 0.5 g/L, pH 4, contact time 60 s, and initial dye concentration 30 mg/L) was very close to the experimental value (96.16%) determined in batch experiment. In the optimization, R2 and R2adj correlation coefficients for the model were evaluated as 0.95 and 0.90, respectively.

Effective removal of Congo red dye from aqueous solution using modified xanthan gum/silica hybrid nanocomposite as adsorbent.

PubMed

Ghorai, Soumitra; Sarkar, Amit Kumar; Panda, A B; Pal, Sagar

2013-09-01

The aim of this work is to study the feasibility of XG-g-PAM/SiO2 nanocomposite towards its potential application as high performance adsorbent for removal of Congo red (CR) dye from aqueous solution. The surface area, average pore size and total pore volume of the developed nanocomposite has been determined. The efficiency of CR dye adsorption depends on various factors like pH, temperature of the solution, equilibrium time of adsorption, agitation speed, initial concentration of dye and adsorbent dosage. It has been observed that the nanocomposite is having excellent CR dye adsorption capacity (Q0=209.205 mg g(-1)), which is considerably high. The dye adsorption process is controlled by pseudo-second order and intraparticle diffusion kinetic models. The adsorption equilibrium data correlates well with Langmuir isotherm. Desorption study indicates the efficient regeneration ability of the dye loaded nanocomposite. Copyright © 2013 Elsevier Ltd. All rights reserved.

Combined Homogeneous Surface Diffusion Model - Design of experiments approach to optimize dye adsorption considering both equilibrium and kinetic aspects.

PubMed

Muthukkumaran, A; Aravamudan, K

2017-12-15

Adsorption, a popular technique for removing azo dyes from aqueous streams, is influenced by several factors such as pH, initial dye concentration, temperature and adsorbent dosage. Any strategy that seeks to identify optimal conditions involving these factors, should take into account both kinetic and equilibrium aspects since they influence rate and extent of removal by adsorption. Hence rigorous kinetics and accurate equilibrium models are required. In this work, the experimental investigations pertaining to adsorption of acid orange 10 dye (AO10) on activated carbon were carried out using Central Composite Design (CCD) strategy. The significant factors that affected adsorption were identified to be solution temperature, solution pH, adsorbent dosage and initial solution concentration. Thermodynamic analysis showed the endothermic nature of the dye adsorption process. The kinetics of adsorption has been rigorously modeled using the Homogeneous Surface Diffusion Model (HSDM) after incorporating the non-linear Freundlich adsorption isotherm. Optimization was performed for kinetic parameters (color removal time and surface diffusion coefficient) as well as the equilibrium affected response viz. percentage removal. Finally, the optimum conditions predicted were experimentally validated. Copyright © 2017 Elsevier Ltd. All rights reserved.

Decolorization of a reactive copper-phthalocyanine dye under methanogenic conditions.

PubMed

Beydili, M I; Matthews, R D; Pavlostathis, S G

2001-01-01

The objective of this research was to assess the biological decolorization of the copper-phthalocyanine dye Reactive Blue 7 (RB7) under methanogenic conditions using a mixed, methanogenic culture in a repetitive dye addition batch assay. The initial rate of decolorization was 13.2 mg/L-d and 5.7 mg/L-d for the first and second dye addition, respectively. For an initial RB7 concentration of ca. 300 mg/L, the extent of decolorization remained constant (about 62%) for each repetitive RB7 addition and resulted in a residual color build up. Declining absorbance ratio values (A664/A620) with increasing incubation time confirmed that the observed color removal was due to transformation as opposed to adsorption on the biomass. Chemical decolorization assays using sodium dithionite as the reducing agent resulted in similar absorbance spectra to that obtained after biological decolorization. In addition, in both the chemical and biological decolorization assays, partial oxidation of the reduced dye solution upon exposure to air resulted in higher residual color, indicating that the reduction and decolorization of RB7 are partially reversible. These results also suggest that RB7 reduction and decolorization both chemically and biologically most likely followed a similar reduction mechanism.

Effect of light on the kinetics and equilibrium of the textile dye (Reactive Red 120) adsorption by Helianthus annuus hairy roots.

PubMed

Srikantan, Chitra; Suraishkumar, G K; Srivastava, Smita

2018-06-01

The study demonstrates for the first time that light influences the adsorption equilibrium and kinetics of a dye by root culture system. The azo dye (Reactive Red 120) adsorption by the hairy roots of H. annuus followed a pseudo first-order kinetic model and the adsorption equilibrium parameters were best estimated using Langmuir isotherm. The maximum dye adsorption capacity of the roots increased 6-fold, from 0.26 mg g -1 under complete dark conditions to 1.51 mg g -1 under 16/8 h light/dark photoperiod. Similarly, adsorption rate of the dye and removal (%) also increased in the presence of light, irrespective of the initial concentration of the dye (20-110 mg L -1 ). The degradation of the azo dye upon adsorption by the hairy roots of H. annuus was also confirmed. In addition, a strategy for simultaneous dye removal and increased alpha-tocopherol (industrially relevant) production by H. annuus hairy root cultures has been proposed and demonstrated. Copyright © 2018 Elsevier Ltd. All rights reserved.

Magnetic graphene oxide for adsorption of organic dyes from aqueous solution

NASA Astrophysics Data System (ADS)

Drashya, Lal, Shyam; Hooda, Sunita

2018-05-01

Graphene oxide (GO), a 2-D carbon nanomaterial, large surface area, oxygen-containing groups (like: hydroxyl, epoxy and carboxyl) and excellent water dispersibility due to it is good adsorbent dye removal from pollutant water1. But it's difficult to separate GO from water after adsorption. Therefore, Iron oxide was introduced in Graphene oxide by decorating method to make separation more efficient2. We present herein a one step process to prepare Magnetic Graphene oxide (MGO). The Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and Raman Spectroscopy characterized the chemical structure of the MGO composite. The adsorption of dyes onto MGO was studied in relation to initial concentration of Dyes, contact time, adsorbent dose, temperature and pH value of solution. We have studied adsorption capacity of different dyes (Methylene blue and crystal violet) by MGO.

Basic dye decomposition kinetics in a photocatalytic slurry reactor.

PubMed

Wu, Chun-Hsing; Chang, Hung-Wei; Chern, Jia-Ming

2006-09-01

Wastewater effluent from textile plants using various dyes is one of the major water pollutants to the environment. Traditional chemical, physical and biological processes for treating textile dye wastewaters have disadvantages such as high cost, energy waste and generating secondary pollution during the treatment process. The photocatalytic process using TiO2 semiconductor particles under UV light illumination has been shown to be potentially advantageous and applicable in the treatment of wastewater pollutants. In this study, the dye decomposition kinetics by nano-size TiO2 suspension at natural solution pH was experimentally studied by varying the agitation speed (50-200 rpm), TiO2 suspension concentration (0.25-1.71 g/L), initial dye concentration (10-50 ppm), temperature (10-50 degrees C), and UV power intensity (0-96 W). The experimental results show the agitation speed, varying from 50 to 200 rpm, has a slight influence on the dye decomposition rate and the pH history; the dye decomposition rate increases with the TiO2 suspension concentration up to 0.98 g/L, then decrease with increasing TiO2 suspension concentration; the initial dye decomposition rate increases with the initial dye concentration up to a certain value depending upon the temperature, then decreases with increasing initial dye concentration; the dye decomposition rate increases with the UV power intensity up to 64 W to reach a plateau. Kinetic models have been developed to fit the experimental kinetic data well.

Adsorption of C.I. Natural Red 4 onto Spongin Skeleton of Marine Demosponge

PubMed Central

Norman, Małgorzata; Bartczak, Przemysław; Zdarta, Jakub; Tylus, Włodzimierz; Szatkowski, Tomasz; Stelling, Allison L.; Ehrlich, Hermann; Jesionowski, Teofil

2014-01-01

C.I. Natural Red 4 dye, also known as carmine or cochineal, was adsorbed onto the surface of spongin-based fibrous skeleton of Hippospongia communis marine demosponge for the first time. The influence of the initial concentration of dye, the contact time, and the pH of the solution on the adsorption process was investigated. The results presented here confirm the effectiveness of the proposed method for developing a novel dye/biopolymer hybrid material. The kinetics of the adsorption of carmine onto a marine sponge were also determined. The experimental data correspond directly to a pseudo-second-order model for adsorption kinetics (r2 = 0.979–0.999). The hybrid product was subjected to various types of analysis (FT-IR, Raman, 13C CP/MAS NMR, XPS) to investigate the nature of the interactions between the spongin (adsorbent) and the dye (the adsorbate). The dominant interactions between the dye and spongin were found to be hydrogen bonds and electrostatic effects. Combining the dye with a spongin support resulted with a novel hybrid material that is potentially attractive for bioactive applications and drug delivery systems. PMID:28787926

Application potential of grapefruit peel as dye sorbent: kinetics, equilibrium and mechanism of crystal violet adsorption.

PubMed

Saeed, Asma; Sharif, Mehwish; Iqbal, Muhammad

2010-07-15

This study reports the sorption of crystal violet (CV) dye by grapefruit peel (GFP), which has application potential in the remediation of dye-contaminated wastewaters using a solid waste generated by the citrus fruit juice industry. Batch adsorption of CV was conducted to evaluate the effect of initial pH, contact time, temperature, initial dye concentration, GFP adsorbent dose, and removal of the adsorbate CV dye from aqueous solution to understand the mechanism of sorption involved. Sorption equilibrium reached rapidly with 96% CV removal in 60 min. Fit of the sorption experimental data was tested on the pseudo-first and pseudo-second-order kinetics mathematical equations, which was noted to follow the pseudo-second-order kinetics better, with coefficient of correlation > or = 0.992. The equilibrium process was well described by the Langmuir isotherm model, with maximum sorption capacity of 254.16 mg g(-1). The GFP was regenerated using 1 M NaOH, with up to 98.25% recovery of CV and could be reused as a dye sorbent in repeated cycles. GFP was also shown to be highly effective in removing CV from aqueous solution in continuous-flow fixed-bed column reactors. The study shows that GFP has the potential of application as an efficient sorbent for the removal of CV from aqueous solutions. 2010 Elsevier B.V. All rights reserved.

Polyethylene Glycol (PEG) Linked to Near Infrared (NIR) Dyes Conjugated to Chimeric Anti-Carcinoembryonic Antigen (CEA) Antibody Enhances Imaging of Liver Metastases in a Nude-Mouse Model of Human Colon Cancer

PubMed Central

Maawy, Ali A.; Hiroshima, Yukihiko; Zhang, Yong; Luiken, George A.; Hoffman, Robert M.; Bouvet, Michael

2014-01-01

We report here that polyethylene glycol (PEG) linked to near infrared dyes conjugated to chimeric mouse-human anti-carcinoembryonic antigen (CEA) antibody greatly improves imaging of liver metastases in a nude mouse model of colon-cancer experimental metastases. PEGylated and non-PEGylated DyLight 650 and 750 dyes were conjugated to the chimeric anti-CEA antibody. The dyes were initially injected intravenously into nude mice without tumors. Tissue biodistribution was determined by tissue sonication and analyzing tissue dye concentration profiles over time. PEGylated dyes had significantly lower accumulation in the liver (p = 0.03 for the 650 dyes; p = 0.002 for the 750 dyes) compared to non-PEGylated dyes. In an experimental liver metastasis model of HT-29 colon cancer, PEGylated dyes conjugated to the anti-CEA antibody showed good labeling of metastatic tumors with high contrast between normal and malignant tissue which was not possible with the non-PEGylated dyes since there was so much non-specific accumulation in the liver. PEGylation of the DyLight 650 and 750 NIR dyes significantly altered tissue biodistribution, allowing brighter tissue labeling, decreased accumulation in normal organs, particularly the liver. This enabled high fidelity and high contrast imaging of liver metastases. PMID:24859320

Alkali, thermo and halo tolerant fungal isolate for the removal of textile dyes.

PubMed

Kaushik, Prachi; Malik, Anushree

2010-11-01

In the present study potential of a fungal isolate Aspergillus lentulusFJ172995, was investigated for the removal of textile dyes. The removal percentages of dyes such as Acid Navy Blue, Orange-HF, Fast Red A, Acid Sulphone Blue and Acid Magenta were determined as 99.43, 98.82, 98.75, 97.67 and 69.98, respectively. None of the dyes inhibited the growth of A. lentulus. Detailed studies on growth kinetics, mechanism of dye removal and effect of different parameters on dye removal were conducted using Acid Navy Blue dye. It was observed that A. lentulus could completely remove Acid Navy Blue even at high initial dye concentrations, up to 900 mg/L. Highest uptake capacity of 212.92 mg/g was observed at an initial dye concentration of 900 mg/L. Dye removing efficiency was not altered with the variation of pH; and biomass production as well as dye removal was favored at higher temperatures. Dye removal was also efficient even at high salt concentration. Through growth kinetics studies it was observed that the initial exponential growth phase coincided with the phase of maximal dye removal. Microscopic studies suggest that bioaccumulation along with biosorption is the principle mechanism involved in dye removal by A. lentulus. Thus, it is concluded that being alkali, thermo and halo tolerant, A. lentulus isolate has a great potential to be utilized for the treatment of dye bearing effluents which are usually alkaline, hot and saline. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Carbon composite lignin-based adsorbents for the adsorption of dyes.

PubMed

Wang, Xiaohong; Jiang, Chenglong; Hou, Bingxia; Wang, Yingying; Hao, Chen; Wu, Jingbo

2018-05-10

Carbon composite lignin-based adsorbent were prepared through hydrothermal method with glucose as carbon source, calcium lignosulfonate and triethylene tetramine as raw materials, respectively. The optimum synthesis conditions were determined by investigating the addition of carbon and triethylene tetramine. The adsorbent was used for the adsorption of azo dyes Congo red and Eriochrome blue black R, and the five factors affecting the adsorption were discussed, including pH of dyes, initial concentration, adsorption time, adsorption temperature and adsorbent dosage. The corresponding adsorption mechanism such as pseudo first order kinetics, pseudo second order kinetics, intraparticle diffusion, Langmuir adsorption isotherm, Freundlich isotherm, Temkin isotherm, Dubinin-Radushkevich adsorption isotherm, thermodynamics were also studied. When the dye concentration is 40 mg L -1 , Congo red and Eriochrome blue black R dye removal rates reach 99%. Moreover, the adsorption process of two kinds of dyes follow the pseudo second order kinetics and the Langmuir adsorption isotherm. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mechanisms of Alizarin Red S and Methylene blue biosorption onto olive stone by-product: Isotherm study in single and binary systems.

PubMed

Albadarin, Ahmad B; Mangwandi, Chirangano

2015-12-01

The biosorption process of anionic dye Alizarin Red S (ARS) and cationic dye methylene blue (MB) as a function of contact time, initial concentration and solution pH onto olive stone (OS) biomass has been investigated. Equilibrium biosorption isotherms in single and binary systems and kinetics in batch mode were also examined. The kinetic data of the two dyes were better described by the pseudo second-order model. At low concentration, ARS dye appeared to follow a two-step diffusion process, while MB dye followed a three-step diffusion process. The biosorption experimental data for ARS and MB dyes were well suited to the Redlich-Peterson isotherm. The maximum biosorption of ARS dye, qmax = 16.10 mg/g, was obtained at pH 3.28 and the maximum biosorption of MB dye, qmax = 13.20 mg/g, was observed at basic pH values. In the binary system, it was indicated that the MB dye diffuses firstly inside the biosorbent particle and occupies the biosorption sites forming a monodentate complex and then the ARS dye enters and can only bind to untaken sites; forms a tridentate complex with OS active sites. Copyright © 2015 Elsevier Ltd. All rights reserved.

Techno-economical optimization of Reactive Blue 19 removal by combined electrocoagulation/coagulation process through MOPSO using RSM and ANFIS models.

PubMed

Taheri, M; Alavi Moghaddam, M R; Arami, M

2013-10-15

In this research, Response Surface Methodology (RSM) and Adaptive Neuro Fuzzy Inference System (ANFIS) models were applied for optimization of Reactive Blue 19 removal using combined electrocoagulation/coagulation process through Multi-Objective Particle Swarm Optimization (MOPSO). By applying RSM, the effects of five independent parameters including applied current, reaction time, initial dye concentration, initial pH and dosage of Poly Aluminum Chloride were studied. According to the RSM results, all the independent parameters are equally important in dye removal efficiency. In addition, ANFIS was applied for dye removal efficiency and operating costs modeling. High R(2) values (≥85%) indicate that the predictions of RSM and ANFIS models are acceptable for both responses. ANFIS was also used in MOPSO for finding the best techno-economical Reactive Blue 19 elimination conditions according to RSM design. Through MOPSO and the selected ANFIS model, Minimum and maximum values of 58.27% and 99.67% dye removal efficiencies were obtained, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Photocatalytic studies of electrochemically synthesized polysaccharide-functionalized ZnO nanoparticles

NASA Astrophysics Data System (ADS)

Kaur, Simranjeet; Kaur, Harpreet

2018-05-01

The present work reports the electrochemical synthesis of polysaccharide-functionalized ZnO nanoparticles using sodium hydroxide, starch, and zinc electrodes for the degradation of cationic dye (Rhodamine-B) under sunlight. Physiochemical properties of synthesized sample have been characterized by different techniques such as XRD, TEM, FESEM, EDS, IR, and UV-visible spectroscopic techniques. The influence of various factors such as effect of dye concentration, contact time, amount of photocatalyst, and pH has been studied. The results obtained from the photodegradation study showed that degradation rate of Rhodamine-B dye has been increased with increase of amount of photocatalyst and decreased with increase in initial dye concentration. Furthermore, the kinetics of the degradation has been investigated. It has been found that the photodegradation of Rhodamine-B dye follows pseudo-first-order kinetics and prepared photocatalyst can effectively degrade the cationic dye. Thus, this ecofriendly and efficient photocatalyst can be used for the treatment of dye-contaminated water. This catalyst also showed the antibacterial activity against Bacillus pumilus and Escherichia coli bacterial strains, so the synthesized nanoparticles also have the pharmaceutical properties.

Sugarcane bagasse powder as biosorbent for reactive red 120 removals from aqueous solution

NASA Astrophysics Data System (ADS)

Ahmad, S.; Wong, Y. C.; Veloo, K. V.

2018-04-01

Reactive red 120 is used as a textile dye for fabric coloring. The dye waste is produced during textile finishing process subsequently released directly to water bodies which giving harmful effects to the environment due to the carcinogenic characteristic. Adsorption process becomes an effective treatment to treat textile dye. This research emphasizes the treatment of textile dye namely reactive red 120 (RR120) by using sugarcane bagasse powder. The batch study was carried out under varying parameters such as 60 minutes contact time, pH (1-8), dye concentration (5-25 mg/L), particle size (125-500 μm) and biosorbent dosage (0.01-0.2 g/L). The maximum adsorption percentage of RR120 was 94.62%. The adsorption of dye was increased with the decreasing of pH, initial dye concentration and particle size. Sugarcane bagasse powder as low-cost biosorbent was established using Fourier Transform Infrared (FTIR) and scanning electron microscopy (SEM). This locally agricultural waste could be upgraded into useful material which is biosorbent that promising for decolorization of colored textile wastewater.

Biosorption of six basic and acidic dyes on brown alga Sargassum ilicifolium: optimization, kinetic and isotherm studies.

PubMed

Tabaraki, Reza; Sadeghinejad, Negar

2017-06-01

Biosorption of Methyl Blue (MB), Fuchsin Acid (FA), Rhodamine B (RB), Methylene Blue (MEB), Bromocresol purple (BC) and Methyl Orange (MO) onto Sargassum ilicifolium was studied in a batch system. Effect of dye structure on biosorption by Sargassum ilicifolium was studied to define the correlation between chemical structure and biosorption capacity. Different dye groups such as triarylmethane (MB, FA and BC), monoazo (MO), thiazine (MEB) and xanthene (RB) were studied. At optimum experimental conditions for each dye, biosorption capacity was determined and compared. The results indicate that the chemical structure (triarylmethane, monoazo, thiazine, xanthene), number of sulfonic groups, basicity (element of chromophore group: S, N, O) and molecular weight of dye molecules influence their biosorption capacity. Experimental parameters such as biosorbent dose, pH, contact time, and initial dye concentration were optimized for each dye. The biosorption kinetic data were successfully described by the pseudo second-order model. The biosorption results were also analyzed by the Langmuir and Freundlich isotherms. Finally, biosorption capacities obtained using Sargassum ilicifolium were compared with the ones presented in the literature.

Effect of initial treatment in the preparation of natural indigo dye from Indigofera tinctoria

NASA Astrophysics Data System (ADS)

Purnama, Herry; Hidayati, Nur; Safitri, Dyah S.; Rahmawati, Sofia

2017-06-01

The current tinting industries return to the use of natural dyes because of their characteristics including safe and environmentally friendly. Indonesia can widely promote the potential of natural colours due to the availability of abundant natural dye plants. One of the potential plants that generates blue colour is Indigofera tinctoria. This research was conducted to improve the quality and quantity of natural indigo dye for batik production that supports the environment sustainability. The indigo dark blue paste was produced by initial treatment of soaking in cold water for 48 hours. The 48 hours fermentation anaerobic conditions reached optimum temperature, due to time and pH were also met by nutrients. Aeration was done in ten minutes using an aquarium air pump to increase mixing in water immersion with solution of calcium oxide. Indoxyl in the fermented leaves of Indigofera tinctoria is easily oxidized by air in alkali solution that will form pigment indigo. In that condition, lime (CaO) can be used in the manufacture of indigo paste. In this study, the higher concentrated of blue colour was achieved by lesser amount of lime. The soaking treatment in cold water produced high amount of dyes rather than the initial treatment by both hot water and grounding the indigo leaves. Analysis were done by using UV-Vis Spectrophotometry which showed the value of absorbance. The sample that was soaked in 5 liters of water added by a kilogram of Indigofera tinctoria leaves and 15 grams of lime for 48 hours, obtained the highest absorbance or concentration level. The application of the indigo dyes with or without mordanting agent was also tested for colour fastness.

Characterization of tannery sludge activated carbon and its utilization in the removal of azo reactive dye.

PubMed

Geethakarthi, A; Phanikumar, B R

2012-03-01

The removal of azo Reactive Red 31(RR31) from synthetic dye solution using tannery sludge-developed activated carbon (TSC) was investigated. TSC was prepared from a combination of physical and chemical activation. The developed TSC was characterized by FT-IR, SEM, TG-DTA, specific surface area and zero point charge of pH (pH(zpc)). The isotherm models, kinetic models and thermodynamic parameters were also analysed to describe the adsorptive behaviour of TSC. The effect of contact time, initial dye concentration, carbon dosage, agitation speed, initial pH and temperature were carried out for batch adsorption studies. The isotherm plot of the dye RR31 on TSC fitted better with the Langmuir adsorption isotherm than the Freundlich model. The maximum monolayer adsorption capacity of TSC in the removal of RR31 ranged from 23.15 to 39.37 mg/g. The thermodynamic parameters showed the endothermic and physical nature of the Reactive Red 31 adsorption on TSC. The entropy and enthalpy values were 181.515 J/Kmol and 5.285 kJ/mol, respectively. The developed cationic tannery sludge carbon was found to be an effective adsorbent in the removal of the anionic azo reactive dye RR31.

Abatement of Azo Dye from Wastewater Using Bimetal-Chitosan

PubMed Central

Asgari, Ghorban; Farjadfard, Sima

2013-01-01

We introduce a new adsorbent, bimetallic chitosan particle (BCP) that is successfully synthesized and applied to remove the orange II dye from wastewater. The effects of pH, BCP quantity, and contact time are initially verified on the basis of the percentage of orange II removed from the wastewater. Experimental data reveal that the Cu/Mg bimetal and chitosan have a synergistic effect on the adsorption process of the adsorbate, where the dye adsorption by Cu/Mg bimetal, chitosan alone, and bimetal-chitosan is 10, 49, and 99.5%, respectively. The time required for the complete decolorization of orange II by 1 mg/L of BCP is 10 min. The Langmuir model is the best fit for the experimental data, which attains a maximum adsorption capacity of 384.6 mg/g. The consideration of the kinetic behavior indicates that the adsorption of orange II onto the BCP fits best with the pseudo-second-order and Elovich models. Further, the simulated azo dye wastewater can be effectively treated using a relatively low quantity of the adsorbent, 1 mg/L, within a short reaction time of 20 min. Overall, the use of BCP can be considered a promising method for eliminating the azo dye from wastewater effectively. PMID:24348163

Adsorption of Acid Blue 25 dye by bentonite and surfactant modified bentonite

NASA Astrophysics Data System (ADS)

Jeeva, Mark; Wan Zuhairi, W. Y.

2018-04-01

Adsorption of Acid Blue (AB 25) from water via batch adsorption experiments onto Na-Bentonite (NB) and CTAB-modified bentonite (CTAB-Ben) was investigated. Studies concerning the factors influencing the adsorption capacities of NB and CTAB-Ben, such as initial dye concentration, adsorbent dosage, pH, contact time and temperature were investigated and discussed. The results revealed that CTAB-modified bentonite demonstrated high adsorption capacities toward acid dyes, while NB exhibited sorption capacities lower than CTAB-Ben. The maximum adsorption efficiency was found to be 50% at an AB 25 concentration of 50 mg/L, adsorbent dosage of 1.8 g/L, reaction time of 90 min and equilibrium pH of 11. The results of isotherm study fit the Langmuir and Freundlich models (R2 > 0.93) and (R2 > 0.9) respectively.

Response surface methodological approach for the decolorization of simulated dye effluent using Aspergillus fumigatus fresenius.

PubMed

Sharma, Praveen; Singh, Lakhvinder; Dilbaghi, Neeraj

2009-01-30

The aim of our research was to study, effect of temperature, pH and initial dye concentration on decolorization of diazo dye Acid Red 151 (AR 151) from simulated dye solution using a fungal isolate Aspergillus fumigatus fresenius have been investigated. The central composite design matrix and response surface methodology (RSM) have been applied to design the experiments to evaluate the interactive effects of three most important operating variables: temperature (25-35 degrees C), pH (4.0-7.0), and initial dye concentration (100-200 mg/L) on the biodegradation of AR 151. The total 20 experiments were conducted in the present study towards the construction of a quadratic model. Very high regression coefficient between the variables and the response (R(2)=0.9934) indicated excellent evaluation of experimental data by second-order polynomial regression model. The RSM indicated that initial dye concentration of 150 mg/L, pH 5.5 and a temperature of 30 degrees C were optimal for maximum % decolorization of AR 151 in simulated dye solution, and 84.8% decolorization of AR 151 was observed at optimum growth conditions.

Treatment of industrial wastewater containing Congo Red and Naphthol Green B using low-cost adsorbent.

PubMed

Attallah, M F; Ahmed, I M; Hamed, Mostafa M

2013-02-01

The present work investigates the potential use of metal hydroxides sludge (MHS) generated from hot dipping galvanizing plant for adsorption of Congo Red and Naphthol Green B dyes from aqueous solutions. Characterization of MHS included infrared and X-ray fluorescence analysis. The effect of shaking time, initial dye concentration, temperature, adsorbent dosage and pH has been investigated. The results of adsorption experiments indicate that the maximum capacity of Congo Red and Naphthol Green B dyes at equilibrium (q(e)) and percentage of removal at pH 6 are 40 mg/g, 93 %, and 10 mg/g, 52 %, respectively. Some kinetic models were used to illustrate the adsorption process of Congo Red and Naphthol Green B dyes using MHS waste. Thermodynamic parameters such as (ΔG, ΔS, and ΔH) were also determined.

Activated carbon prepared from yerba mate used as a novel adsorbent for removal of tannery dye from aqueous solution.

PubMed

Linhares, Bruno; Weber, Caroline Trevisan; Foletto, Edson Luiz; Paz, Diego Silva; Mazutti, Marcio A; Collazzo, Gabriela Carvalho

2013-01-01

Activated carbon prepared from yerba mate (Ilex paraguariensis) was used as adsorbent for the removal of tannery dye from aqueous solution. The activated carbon was characterized, and it showed a mesoporous texture, with surface area of 537.4 m2 g(-1). The initial dye concentration, contact time and pH influenced the adsorption capacity. The equilibrium data were in good agreement with both Langmuir and Freundlich isotherms. The adsorption kinetics of the tannery dye on activated carbon prepared from yerba mate followed a pseudo-second-order model. The adsorption process was found to be controlled by both external mass-transfer and intraparticle diffusion, but the external diffusion was the dominating process. This work highlights the potential application of activated carbon produced from yerba mate in the field of adsorption.

On the possible long-term fate of oil released in the deepwater horizon incident: estimated by ensembles of dye release simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maltrud, Mathew E.; Peacock, Synte L.; Visbeck, Martin

2010-08-01

We have conducted an ensemble of 20 simulations using a high-resolution global ocean model in which dye was continuously injected at the site of the Deepwater Horizon drilling rig for two months. We then extended these simulations for another four months to track the dispersal of the dye in the model. We have also performed five simulations in which dye was continuously injected at the site of the spill for four months and then run out to one year from the initial spill date. The experiments can elucidate the time and space scales of dispersal of polluted waters and alsomore » give a quantitative estimate of dilution rate, ignoring any sink terms such as chemical or biological degradation.« less

[Biosorption of crystal violet and malachite green by Rhodotorula graminis Y-5].

PubMed

Hu, Rong; Huang, Jian-Bo; Yang, Zhou-Ping; Cheng, Zi-Zhang; Jing, De-Jun; Huang, Qian-Ming

2011-12-01

With a shaker, this paper studied the characteristics of the biosorption of crystal violet and malachite green by Rhodotorula graminis Y-5 under different adsorption time, initial pH, and temperature, as well as the desorption and recycling use of the dyes. The biosorption of crystal violet and malachite green by R. graminis Y-5 had the peaks (93.8% and 87.7%, respectively) at pH 7.0, dye concentration 50 mg x L(-1), 150 r x min(-1), 30 degrees C, and lasting 10 hours. After desorption, the biosorption rate of crystal violet and malachite green by R. graminis was 85.5% and 78.5%, respectively, indicating that the biosorption of crystal violet and malachite green was reversible, and the recycling use of the dyes by R. graminis was quite good, i. e., the dyes were renewable and could be recycled. Biosorption could be the mechanism of the decolorization of the dyes. The dyes were mostly adsorbed on the R. graminis surface -OH. The adsorption process was fast, efficient, and reversible, suggesting that R. graminis had a high potential for waste water treatment.

One step effective removal of Congo Red in chitosan nanoparticles by encapsulation

NASA Astrophysics Data System (ADS)

Alver, Erol; Bulut, Mehmet; Metin, Ayşegül Ülkü; Çiftçi, Hakan

2017-01-01

Chitosan nanoparticles (CNPs) were prepared with ionotropic gelation between chitosan and tripolyphosphate for the removal of Congo Red. The production of chitosan nanoparticles and the dye removal process was carried out in one-step. The removal efficiency of Congo Red by encapsulation within chitosan from the aqueous solution and its storage stability are examined at different pH values. The influence of some parameters such as the initial dye concentration, pH value of the dye solution, electrolyte concentration, tripolyphosphate concentration, mixing time and speed on the encapsulation is examined. Congo Red removal efficiency and encapsulation capacity of chitosan nanoparticles were determined as above 98% and 5107 mg Congo Red/g chitosan, respectively.

Marine green algae Codium iyengarii as a good bio-sorbent for elimination of reactive black 5 from aqueous solution.

PubMed

Azmat, Rafia

2014-09-01

The green seaweeds Codium iyengarii (C. iyengarii) was used to prepare as an adsorbent surface for the deletion of Reactive Black 5 (RB 5) from aqueous solution via adsorption. The batch technique was adopted under the optimal condition of amount of adsorbent, agitation time, concentration of dye, and at neutral and low pH. The depletion in concentration of the dye was monitored by Schimadzo 180 AUV/Visible spectrophotometer. It was initially monolayer adsorption, which showed multilayered formation later on with the passage of time at low and neutral pH. The Results displayed that adsorptive ability of C. iyengarii was 1.95-3.82mg/g with an elevation in primary application of dye contents (50ppm-70 ppm). The elimination data were well stable into the Langmuir and Freundlich adsorption isotherm equations. The Langmuir (R2=0.9848) and Freundlich (R2=0.9441) constants for biosorption of RB 5 on green algae were determined. The coefficient relation values suggested that the Langmuir isotherm was well fitted. It explained the interaction of surface molecules, which helps in well organization of dye molecules in a monolayer formation initially on algal biomass. The pseudo first and second order rate equations were applied to link the investigational statistics and found that the second order rate expression was found to be more suitable for both the models. The absorption spectrum of RB 5 before and after adsorption with respect to time was monitored which clearly indicate that C. iyengarii was much effective surface at very low quantity.

Fixed-bed adsorption study of methylene blue onto pyrolytic tire char

NASA Astrophysics Data System (ADS)

Makrigianni, Vassiliki; Giannakas, Aris; Papadaki, Maria; Albanis, Triantafyllos; Konstantinou, Ioannis

2016-04-01

In this work, the adsorption efficiency of acid treated pyrolytic tire char to cationic methylene blue (MB) dye adsorption from aqueous solutions was investigated by fixed-bed adsorption column experiments. The effects of the initial dye concentration (10 - 40 mg L-1) and feed flow rate (50 - 150 mL min -1) with a fixed bed height (15 cm) were studied in order to determine the breakthrough characteristics of the adsorption system. The Adams-Bohart, Yoon-Nelson and Thomas model were applied to the adsorption of MB onto char at different operational conditions to predict the breakthrough curves and to determine the characteristic parameters of the column. The results showed that the maximum adsorbed quantities decreased with increasing flow rate and increased with increasing initial MB concentration. Breakthrough time and exhaustion time increased with decreasing inlet dye concentration and flow rate. In contrast with Adams-Bohart model, Yoon-Nelson model followed by Thomas model were found more suitable to describe the fixed-bed adsorption of methylene blue by char. The correlation coefficient values R2 for both models at different operating conditions are higher than 0.9 and the low average relative error values provided very good fittings of experimental data at different operating conditions. Higher adsorption capacity of 3.85 mg g -1 was obtained at 15 cm of adsorbent bed height, flow rate of 100 mL min -1and initial MB concentration of 40 mg L-1. Although that activated carbons exhibited higher adsorption capacities in the literature, acid-treated pyrolytic tire char was found to be considerably efficient adsorbent for the removal of MB dye column taking into account the advantages of the simpler production process compared to activated carbons, as well as, the availability of waste tire feedstock and concurrent waste tire management.

Uniform Cu{sub 2}Cl(OH){sub 3} hierarchical microspheres: A novel adsorbent for methylene blue adsorptive removal from aqueous solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Wei; Gao, Pin; Xie, Jimin, E-mail: xiejm391@sohu.com

2013-08-15

Using the solution phase method without any surfactants or templates, the hierarchical of Cu{sub 2}Cl(OH){sub 3} microspheres were synthesized by freeze drying. The size and surface area of the microspheres are ca. 1–2 µm and 76.61 m{sup 2} g{sup −1}, respectively. A possible formation mechanism is presented based on the experimental results. Methylene blue was chosen to investigate the adsorption capacity of the as-prepared adsorbent. The effects of various experimental parameters, such as pH, initial dye concentration, and contact time were investigated. The results showed that the dye removal increased with the increasing in the initial concentration of the dyemore » and also increased in the amount of microspheres used and initial pH. Adsorption data fitted well with the Freundlich adsorption isotherm. The thermodynamic analysis presented the exothermic, spontaneous and more ordered arrangement process. The microspheres could be employed effective for removal of dyes from aqueous solution. - Graphical abstract: The single-crystalline hierarchical Cu{sub 2}Cl(OH){sub 3} spheres can be prepared for the first time by using a template-free process through freeze-drying. Meanwhile, the hierarchical spheres exhibited high adsorption capacity to methylene blue. Display Omitted - Highlights: • Cu{sub 2}Cl(OH){sub 3} microspheres were successfully synthesized through a freeze drying process. • A possible formation mechanism of hierarchical microspheres was presented. • The Cu{sub 2}Cl(OH){sub 3} microspheres have high methylene blue adsorption capacity. • Methylene blue adsorption is a spontaneous and exothermic process. • The adsorption mechanism of microspheres onto dye was proposed in detail.« less

Assessment of the breakdown products of solar/UV induced photolytic degradation of food dye tartrazine.

PubMed

dos Santos, Tuane Cristina; Zocolo, Guilherme Julião; Morales, Daniel Alexandre; Umbuzeiro, Gisela de Aragão; Zanoni, Maria Valnice Boldrin

2014-06-01

The food dye tartrazine (CI 19140) was exposed to UV irradiation from an artificial source, a mercury vapor lamp, and a natural one, sunlight. It was observed that conditions such as energy dose, irradiation time, pH and initial dye concentration affected its discoloration. There was 100% of color removal, after 30min of irradiation, when a dye solution 1×10(-5)molL(-1) was submitted to an energy dose of 37.8Jcm(-2). Liquid Chromatography coupled to Diode Array Detection and Mass Spectrometry confirmed the cleavage of the chromophore group and the formation of five by-products at low concentration. Although by-products were formed, the Salmonella/microsome mutagenicity assay performed for both, the dye solution at a dose of 5.34mg/plate and the solutions obtained after exposure to UV irradiation, did not present mutagenic activity for TA98 and TA100 with and without S9. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multi-responses optimization of simultaneous biosorption of cationic dyes by live yeast Yarrowia lipolytica 70562 from binary solution: Application of first order derivative spectrophotometry.

PubMed

Dil, Ebrahim Alipanahpour; Ghaedi, Mehrorang; Ghezelbash, Gholam Reza; Asfaram, Arash

2017-05-01

Present study is based on application of live yeast Yarrowia lipolytica 70562 as new biosorbent was investigated for the simultaneous biosorption of Crystal Violet (CV) and Brilliant Green (BG) from wastewater. The effect of operating parameters such as initial dye concentrations (6-14mgL -1 ), solution pH (4.0-8.0) and contact time (4-20h) was investigated by response surface methodology (RSM) for modeling and optimization of biosorption process and accordingly the best operational conditions was set as: initial CV and BG concentration of 8.0, and 10mgL -1 , pH of 7.0 and contact time of 16h. Above specified conditions lead to achievement of maximum biosorption of 98.823% and 99.927% for CV and BG dyes, respectively. The experimental equilibrium data well explained according to Langmuir isotherm model with maximum biosorption capacity of 65.359 and 56.497mgg -1 for BG and CV, respectively. The second order and intraparticle diffusion models as cooperative mechanism has high efficiency and performance for interpretation of real data. Copyright © 2017. Published by Elsevier Inc.

Travel times, streamflow velocities, and dispersion rates in the Missouri River upstream from Canyon Ferry Lake, Montana

USGS Publications Warehouse

Whiteman, Aroscott

2012-01-01

In 2010, the U.S. Geological Survey, in cooperation with the Montana Department of Environmental Quality, initiated a dye-tracer study to determine travel times, streamflow velocities, and longitudinal dispersion rates for the Missouri River upstream from Canyon Ferry Lake. For this study, rhodamine WT (RWT) dye was injected at two locations, Missouri River Headwaters State Park in early September and Broadwater-Missouri Dam (Broadwater Dam) in late August 2010. Dye concentrations were measured at three sites downstream from each dye-injection location. The study area was a 41.2-mile reach of the Missouri River from Trident, Montana, at the confluence of the Jefferson, Madison, and Gallatin Rivers (Missouri River Headwaters) at river mile 2,319.40 downstream to the U.S. Route 12 Bridge (Townsend Bridge), river mile 2,278.23, near Townsend, Montana. Streamflows were reasonably steady and ranged from 3,070 to 3,700 cubic feet per second. Mean velocities were calculated for each subreach between measurement sites for the leading edge, peak concentration, centroid, and trailing edge at 10 percent of the peak concentration of the dye plume. Calculated velocities for the centroid of the dye plume ranged from 0.80 to 3.02 feet per second within the study reach from Missouri River Headwaters to Townsend Bridge, near Townsend. The mean velocity of the dye plume for the entire study reach, excluding the subreach between the abandoned Milwaukee Railroad bridge at Lombard, Montana (Milwaukee Bridge) and Broadwater-Missouri Dam (Broadwater Dam), was 2.87 feet per second. The velocity of the centroid of the dye plume for the subreach between Milwaukee Bridge and Broadwater Dam (Toston Reservoir) was 0.80 feet per second. The residence time for Toston Reservoir was 8.2 hours during this study. Estimated longitudinal dispersion rates of the dye plume for this study ranged from 0.72 feet per second for the subreach from Milwaukee Bridge to Broadwater Dam to 2.26 feet per second for the subreach from the U.S. Route 287 Bypass Bridge over the Missouri River north of Toston, Montana to Yorks Islands. A relation was determined between travel time of the peak concentration and the time for the dye plume to pass a site (duration of the dye plume). This relation can be used to estimate when the decreasing concentration of a potential contaminant is reduced to 10 percent of its peak concentration for accidental (contaminant or chemical) spills into the upper Missouri River.

Kinetic, isotherm and thermodynamic studies of amaranth dye biosorption from aqueous solution onto water hyacinth leaves.

PubMed

Guerrero-Coronilla, Imelda; Morales-Barrera, Liliana; Cristiani-Urbina, Eliseo

2015-04-01

The present study explored the kinetics, equilibrium and thermodynamics of amaranth (acid red 27) anionic dye (AD) biosorption to water hyacinth leaves (LEC). The effect of LEC particle size, contact time, solution pH, initial AD concentration and temperature on AD biosorption was studied in batch experiments. AD biosorption increased with rising contact time and initial AD concentration, and with decreasing LEC particle size and solution pH. Pseudo-second-order chemical reaction kinetics provided the best correlation for the experimental data. Isotherm studies showed that the biosorption of AD onto LEC closely follows the Langmuir isotherm, with a maximum biosorption capacity of about 70 mg g(-1). The thermodynamic parameters confirm that AD biosorption by LEC is non-spontaneous and endothermic in nature. Results indicate that LEC is a strong biosorbent capable of effective detoxification of AD-laden wastewaters. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dye lasing arrangement including an optical assembly for altering the cross-section of its pumping beam and method

DOEpatents

O'Neil, Richard W.; Sweatt, William C.

1992-01-01

An optical assembly is disclosed herein along with a method of operation for use in a dye lasing arrangement, for example a dye laser oscillator or a dye amplifier, in which a continuous stream of dye is caused to flow through a given zone in a cooperating dye chamber while the zone is being illuminated by light from a pumping beam which is directed into the given zone. This in turn causes the dye therein to lase and thereby produce a new dye beam in the case of a dye laser oscillator or amplify a dye beam in the case of a dye amplifier. The optical assembly so disclosed is designed to alter the pump beam such that the beam enters the dye chamber with a different cross-sectional configuration, preferably one having a more uniform intensity profile, than its initially produced cross-sectional configuration. To this end, the assembly includes a network of optical components which first act on the beam while the latter retains its initially produced cross-sectional configuration for separating it into a plurality of predetermined segments and then recombines the separated components in a predetermined way which causes the recombined beam to have the different cross-sectional configuration.

A potential low cost adsorbent for the removal of cationic dyes from aqueous solutions

NASA Astrophysics Data System (ADS)

Uddin, Md. Tamez; Rahman, Md. Arifur; Rukanuzzaman, Md.; Islam, Md. Akhtarul

2017-10-01

This study was aimed at using mango leaf powder (MLP) as a potential adsorbent for the removal of methylene blue (MB) from aqueous solutions. Characterization of the adsorbent was carried out with scanning electron microscopy, Fourier transform infrared spectroscopy, and nitrogen adsorption-desorption analysis. The pH at the point of zero charge of the adsorbent was determined by titration method and was found a value to be 5.6 ± 0.2. Batch studies were performed to evaluate the influence of various experimental parameters like initial solution pH, contact time, initial concentration of dye and adsorbent dosage on the removal of MB. An adsorption-desorption study was carried out resulting the mechanism of adsorption was carried out by electrostatic force of attraction. The adsorption equilibrium time required for the adsorption of MB on MLP was almost 2 h and 85 ± 5% of the total amount of dye uptake was found to occur in the first rapid phase (30 min). The Langmuir and Freundlich isotherm models were used for modeling the adsorption equilibrium. The experimental equilibrium data could be well interpreted by Langmuir isotherm with maximum adsorption capacity of 156 mg/g. To state the sorption kinetics, the fits of pseudo-first-order and pseudo-second-order kinetic models were investigated. It was obtained that the adsorption process followed the pseudo-second-order rate kinetics. The above findings suggest that MLP can be effectively used for decontamination of dye containing wastewater.

Monodisperse cobalt ferrite nanoparticles assembled on mesoporous graphitic carbon nitride (CoFe2O4/mpg-C3N4): A magnetically recoverable nanocomposite for the photocatalytic degradation of organic dyes

NASA Astrophysics Data System (ADS)

Hassani, Aydin; Eghbali, Paria; Ekicibil, Ahmet; Metin, Önder

2018-06-01

Monodisperse cobalt ferrite (CoFe2O4) nanoparticles (NPs) were synthesized by thermal decomposition of metal precursors in the presence of surfactants and then assembled on mesoporous graphitic carbon nitride (mpg-C3N4) via sonication of two components in ethanol solution. The yielded nanocomposite, namely CoFe2O4/mpg-C3N4, were characterized by using many advanced analytical techniques (TEM, HR-SEM, EDX, XRD, BET, PPMS-VSM, UV-vis DRS and ICP-MS). The magnetic properties of the CoFe2O4/mpg-C3N4 nanocomposite were studied by using M-H and M-T loops and the magnetic saturation and blocking temperature of the nanocomposite were found to be 6.1 emu/g and 269 K, respectively. The nanocomposite were then tested in the photocatalytic degradation of Malachite Green (MG) and showed considerably high photocatalytic activity under UV-light irradiation. The effects of various key operating parameters comprising catalyst amount, initial dye concentration, pH and reaction time span for the degradation of MG dye were studied to optimize the reaction conditions. The maximum degradation efficiency (DE %) of 93.41% was obtained by using 0.08 g L-1 catalyst and 10 mg L-1 MG dye at pH 5 within 120 min reaction time. Besides MG, the photocatalytic degradation of several other organic dyes (methylene blue, acid orange 7 and rhodamine B) was also studied to exhibit the performance of CoFe2O4/mpg-C3N4 nanocomposite under the optimized conditions. The results revealed that the kinetic of dye removal process could be designated through the application of pseudo-first-order kinetic model. In addition to high photocatalytic activity, CoFe2O4/mpg-C3N4 nanocomposite could be magnetically recovered after the dye degradation and reused for consecutive five runs without a significant loss (nearly 17%) in their initial performance.

Photocatalytic degradation and photo-Fenton oxidation of Congo red dye pollutants in water using natural chromite—response surface optimization

NASA Astrophysics Data System (ADS)

Shaban, Mohamed; Abukhadra, Mostafa R.; Ibrahim, Suzan S.; Shahien, Mohamed. G.

2017-12-01

Refined natural Fe-chromite was characterized by XRD, FT-IR, reflected polarized microscope, XRF and UV spectrophotometer. Photocatalytic degradation and photo-Fenton oxidation of Congo red dye by Fe-chromite was investigated using 1 mL H2O2. The degradation of dye was studied as a function of illumination time, chromite mass, initial dye concentration, and pH. Fe-chromite acts as binary oxide system from chromium oxide and ferrous oxide. Thus, it exhibits photocatalytic properties under UV illumination and photo-Fenton oxidation after addition of H2O2. The degradation in the presence of H2O2 reached the equilibrium stage after 8 h (59.4%) but in the absence of H2O2 continued to 12 h (54.6%). Photocatalytic degradation results fitted well with zero, first order and second order kinetic model but it represented by second order rather than by the other models. While the photo-Fenton oxidation show medium fitting with the second order kinetic model only. The values of kinetic rate constants for the photo-Fenton oxidation were greater than those for the photocatalytic degradation. Thus, degradation of Congo red dye using chromite as catalyst is more efficient by photo-Fenton oxidation. Based on the response surface analysis, the predicted optimal conditions for maximum removal of Congo red dye by photocatalytic degradation (100%) were 12 mg/l, 0.14 g, 3, and 11 h for dye concentration, chromite mass, pH, and illumination time, respectively. Moreover, the optimum condition for photo-Fenton oxidation of dye (100%) is 13.5 mg/l, 0.10 g, 4, and 10 h, respectively.

Mixing-induced fluid destratification and ullage condensation

NASA Technical Reports Server (NTRS)

Meserole, Jere S.; Jones, Ogden S.; Fortini, Anthony F.

1987-01-01

In many applications, on-orbit storage and transfer of cryogens will require forced mixing to control tank pressure without direct venting to space. During a no-vent transfer or during operation of a thermodynamic vent system in a cryogen storage tank, pressure control is achieved by circulating cool liquid to the liquid-vapor interface to condense some of the ullage vapor. To measure the pressure and temperature response rates in mixing-induced condensation, an experiment has been developed using Freon 11 to simulate the two-phase behavior of a cryogen. A thin layer at the liquid surface is heated to raise the tank pressure, and then a jet mixer is turned on to circulate the liquid, cool the surface, and reduce the pressure. Many nozzle configurations and flow rates are used. Tank pressure and the temperature profiles in the ullage and the liquid are measured. Initial data from this ground test are shown correlated with normal-gravity and drop-tower dye-mixing data. Pressure collapse times are comparable to the dye-mixing times, whereas the times needed for complete thermal mixing are much longer than the dye-mixing times.

An investigation of anthraquinone dye biodegradation by immobilized Aspergillus flavus in fluidized bed bioreactor.

PubMed

Andleeb, Saadia; Atiq, Naima; Robson, Geoff D; Ahmed, Safia

2012-06-01

Biodegradation and biodecolorization of Drimarene blue K(2)RL (anthraquinone) dye by a fungal isolate Aspergillus flavus SA2 was studied in lab-scale immobilized fluidized bed bioreactor (FBR) system. Fungus was immobilized on 0.2-mm sand particles. The reactor operation was carried out at room temperature and pH 5.0 in continuous flow mode with increasing concentrations (50, 100, 150, 200, 300, 500 mg l(-1)) of dye in simulated textile effluent on the 1st, 2nd, 5th, 8th, 11th, and 14th days. The reactors were run on fill, react, settle, and draw mode, with hydraulic retention time (HRT) of 24-72 h. Total run time for reactor operation was 17 days. The average overall biological oxygen demand (BOD), chemical oxygen demand (COD), and color removal in the FBR system were up to 85.57%, 84.70%, and 71.3%, respectively, with 50-mg l(-1) initial dye concentration and HRT of 24 h. Reductions in BOD and COD levels along with color removal proved that the mechanism of biodecolorization and biodegradation occurred simultaneously. HPLC and LC-MS analysis identified phthalic acid, benzoic acid, 1, 4-dihydroxyanthraquinone, 2,3-dihydro-9,10-dihydroxy-1,4-anthracenedione, and catechol as degradation products of Drimarene blue K(2)RL dye. Phytotoxicity analysis of bioreactor treatments provided evidence for the production of less toxic metabolites in comparison to the parent dye. The present fluidized bed bioreactor setup with indigenously isolated fungal strain in its immobilized form is efficiently able to convert the parent toxic dye into less toxic by-products.

Mesoporous Nb2O5/SiO2 material obtained by sol-gel method and applied as adsorbent of crystal violet dye.

PubMed

Umpierres, Cibele S; Prola, Lizie D T; Adebayo, Matthew A; Lima, Eder C; Dos Reis, Glaydson S; Kunzler, Diego D F; Dotto, G L; Arenas, Leliz T; Benvenutti, Edilson V

2017-03-01

In this work, SiO 2 /Nb 2 O 5 (SiNb) material was prepared using sol-gel method and employed as adsorbent for removal of crystal violet dye (CV). The material was characterized using nitrogen adsorption-desorption isotherms, FTIR spectroscopy, pH pzc , and SEM-EDS. The analysis of N 2 isotherms revealed the presence of micro- and mesopores in the SiNb sample with specific surface area as high as 747 m 2  g -1 . For the CV adsorption process, variations of several parameters such as of pH, temperature, contact time, and concentration of dye of the process were evaluated. The optimum initial pH of the CV dye solution was 7.0. The adsorption kinetic and equilibrium data for CV adsorption were suitably represented by the general-order and Liu models, respectively. The maximum adsorption capacity of the CV dye by SiNb was achieved at 303 K, which attained 116 mg g -1 at this temperaure. Dye effluents were simulated and used to check the applicability of the SiNb material for treatment of effluents - the material showed very good efficiency for decolorization of dye effluents.

Analysis of cytotoxicity and genotoxicity on E. coli, human blood cells and Allium cepa suggests a greater toxic potential of hair dye.

PubMed

Maiti, Swati; Sasmal, Kankaayan; Sinha, Sudarson Sekhar; Singh, Mukesh

2016-02-01

Pharmaceuticals and personal care products (PPCPs) are among the most important emerging environmental contaminants in recent time. PPCPs include wide range of cosmetics, among which hair dyes, are immensely popular in modern society. However, impact of hair dye and its residual discharged to the environment in relation to human health and ecological imbalance have not been widely studied. Based on the result of initial survey among the group of populations of eastern India, three most popular and commonly used permanent hair dyes are selected. Working sample of dye is prepared as recommended on the instructions booklet of the hair dye. The effect of three dyes is studied on Escherichia coli, human red blood cells (RBC), white blood cells (WBC) and Allium cepa bulbs by growth inhibition, hemolysis, 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay and A. cepa micronuclei assays respectively. The Lethal dose (LD) demonstrated significant differences among three dyes and the model systems. In vitro hemolytic assays performed on RBC, and MTT assays on WBC show the cytotoxic effects of hair dye. Significant growth inhibition of E. coli has also been noted. In addition, the root tips of A. cepa treated with the dye have shown major chromosomal abnormalities coupled with cell division retardation. Here low mitotic index confirm cell division retardation. Finally, results of in vitro studies of dye-DNA interactions demonstrate electrostatic interaction. Combing all these results it confirms that hair dyes are cytotoxic and may cause mutagenic effect on living cells irrespective of microbes, plant and animal system. Copyright © 2015 Elsevier Inc. All rights reserved.

Laccase/mediator assisted degradation of triarylmethane dyes in a continuous membrane reactor.

PubMed

Chhabra, Meenu; Mishra, Saroj; Sreekrishnan, Trichur Ramaswamy

2009-08-10

Laccase/mediator systems are important bioremediation agents as the rates of reactions can be enhanced in the presence of the mediators. The decolorization mechanism of two triarylmethane dyes, namely, Basic Green 4 and Acid Violet 17 is reported using Cyathus bulleri laccase. Basic Green 4 was decolorized through N-demethylation by laccase alone, while in mediator assisted reactions, dye breakdown was initiated from oxidation of carbinol form of the dye. Benzaldehyde and N,N-dimethyl aniline were the major end products. With Acid Violet 17, laccase carried out N-deethylation and in mediator assisted reactions, oxidation of the carbinol form of the dye occurred resulting in formation of formyl benzene sulfonic acid, carboxy benzene sulfonic acid and benzene sulfonic acid. Toxicity analysis revealed that Basic Green 4 was toxic and treatment with laccase/mediators resulted in 80-100% detoxification. The treatment of the textile dye solution using laccase and 2,2'-azino-di-(-ethylbenzothiazoline-6-sulfonic acid) (ABTS) was demonstrated in an enzyme membrane reactor. At a hydraulic retention time of 6h, the process was operated for a period of 15 days with nearly 95% decolorization, 10% reduction in flux and 70% recovery of active ABTS.

Adsorptive amputation of hazardous azo dye Congo red from wastewater: a critical review.

PubMed

Raval, Nirav P; Shah, Prapti U; Shah, Nisha K

2016-08-01

Increasing amount of dyes in an ecosystem has propelled the search of various methods for dye removal. Amongst all the methods, adsorption occupies a prominent place in dye removal. Keeping this in mind, many adsorbents used for the removal of hazardous anionic azo dye Congo red (CR) from aqueous medium were reviewed by the authors. The main objectives behind this review article are to assemble the information on scattered adsorbents and enlighten the wide range of potentially effective adsorbents for CR removal. Thus, CR sorption by various adsorbents such as activated carbon, non-conventional low-cost materials, nanomaterials, composites and nanocomposites are surveyed and critically reviewed as well as their sorption capacities are also compared. This review also explores the grey areas of the adsorption performance of various adsorbents with reference to the effects of pH, contact time, initial dye concentration and adsorbent dosage. The equilibrium adsorption isotherm, kinetic and thermodynamic data of different adsorbents used for CR removal were also analysed. It is evident from a literature survey of more than 290 published papers that nanoparticle and nanocomposite adsorbents have demonstrated outstanding adsorption capabilities for CR. Graphical abstract ᅟ.

A rapid and low energy consumption method to decolorize the high concentration triphenylmethane dye wastewater: operational parameters optimization for the ultrasonic-assisted ozone oxidation process.

PubMed

Zhou, Xian-Jiao; Guo, Wan-Qian; Yang, Shan-Shan; Ren, Nan-Qi

2012-02-01

This research set up an ultrasonic-assisted ozone oxidation process (UAOOP) to decolorize the triphenylmethane dyes wastewater. Five factors - temperature, initial pH, reaction time, ultrasonic power (low frequency 20 kHz), and ozone concentration - were investigated. Response surface methodology was used to find out the major factors influencing color removal rate and the interactions between these factors, and optimized the operating parameters as well. Under the experimental conditions: reaction temperature 39.81 °C, initial pH 5.29, ultrasonic power 60 W and ozone concentration 0.17 g/L, the highest color removals were achieved with 10 min reaction time and the initial concentration of the MG solution was 1000 mg/L. The optimal results indicated that the UAOOP was a rapid, efficient and low energy consumption technique to decolorize the high concentration MG wastewater. The predicted model was approximately in accordance with the experimental cases with correlation coefficients R(2) and R(adj)(2) of 0.9103 and 0.8386. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Treatability study of the effluent containing reactive blue 21 dye by ozonation and the mass transfer study of ozone

NASA Astrophysics Data System (ADS)

Velpula, Priyadarshini; Ghuge, Santosh; Saroha, Anil K.

2018-04-01

Ozonation is a chemical treatment process in which ozone reacts with the pollutants present in the effluent by infusion of ozone into the effluent. This study includes the effect of various parameters such as inlet ozone dose, pH of solution and initial concentration of dye on decolorization of dye in terms CRE. The maximum CRE of 98.62% with the reaction rate constant of 0.26 min-1 is achieved in 18 minutes of reaction time at inlet ozone dose of 11.5 g/m3, solution pH of 11 and 30 mg/L of initial concentration of dye. The presence of radical scavenger (Tertiary Butyl Alcohol) suppressed the CRE from 98.62% to 95.4% at high pH values indicates that the indirect mechanism dominates due to the presence of hydroxyl radicals which are formed by the decomposition of ozone. The diffusive and convective mass transfer coefficients of ozone are calculated as 1.78 × 10-5 cm2/sec and 0.075 min-1. It is observed that the fraction of resistance offered by liquid is very much high compared to gas phase indicates that the ozonation is a liquid phase mass transfer controlled operation.

Summary of the National Toxicology Program benzidine dye initiative.

PubMed Central

Morgan, D L; Dunnick, J K; Goehl, T; Jokinen, M P; Matthews, H B; Zeiger, E; Mennear, J H

1994-01-01

The benzidine dye initiative is a research program established by the National Toxicology Program to generate an integrated body of scientific information regarding the potential health risks associated with exposure to benzidine- and benzidine-congener-derived dyes. Because an in-depth evaluation of each of the hundreds of benzidine-congener-derived dyes was considered impractical, the research program was designed to study the metabolism and disposition, genetic toxicity, and in vivo toxicity and carcinogenicity of two primary benzidine congeners, 3,3'-dimethylbenzidine and 3,3'-dimethoxybenzidine, and a select group of prototypical dyes derived from those amines. It was anticipated that by applying the basic information generated in these extensive studies, it would be possible to make regulatory decisions about other dyes after conducting only a minimal number of experiments such as studies of disposition and metabolism, and in vitro mutagenicity. This paper summarizes the results of studies conducted to evaluate the metabolism, disposition, mutagenicity, toxicity, and carcinogenicity of representative benzidine congeners and derived dyes. PMID:7925189

Adsorption of Direct Blue 53 dye from aqueous solutions by multi-walled carbon nanotubes and activated carbon.

PubMed

Prola, Lizie D T; Machado, Fernando M; Bergmann, Carlos P; de Souza, Felipe E; Gally, Caline R; Lima, Eder C; Adebayo, Matthew A; Dias, Silvio L P; Calvete, Tatiana

2013-11-30

Multi-walled carbon nanotubes (MWCNT) and powder activated carbon (PAC) were used as adsorbents for adsorption of Direct Blue 53 dye (DB-53) from aqueous solutions. The adsorbents were characterised using Raman spectroscopy, N2 adsorption/desorption isotherms, and scanning and transmission electron microscopy. The effects of initial pH, contact time and temperature on adsorption capacity of the adsorbents were investigated. At pH 2.0, optimum adsorption of the dye was achieved by both adsorbents. Equilibrium contact times of 3 and 4 h were achieved by MWCNT and PAC adsorbents, respectively. The general order kinetic model provided the best fit of the experimental data compared to pseudo-first order and pseudo-second order kinetic adsorption models. For DB-53 dye, the equilibrium data (298-323 K) were best fitted to the Sips isotherm model. The maximum sorption capacity for adsorption of the dye occurred at 323 K, with the values of 409.4 and 135.2 mg g(-1) for MWCNT and PAC, respectively. Studies of adsorption/desorption were conducted and the results showed that DB-53 loaded MWCNT could be regenerated (97.85%) using a mixture 50% acetone + 50% of 3 mol L(-1) NaOH. Simulated dye house effluents were used to evaluate the application of the adsorbents for effluent treatment (removal of 99.87% and 97.00% for MWCNT and PAC, respectively, were recorded). Copyright © 2013 Elsevier Ltd. All rights reserved.

Degradation of a cationic dye (Rhodamine 6G) using hydrodynamic cavitation coupled with other oxidative agents: Reaction mechanism and pathway.

PubMed

Rajoriya, Sunil; Bargole, Swapnil; Saharan, Virendra Kumar

2017-01-01

In the present study, decolorization and mineralization of a cationic dye, Rhodamine 6G (Rh6G), has been carried out using hydrodynamic cavitation (HC). Two cavitating devices such as slit and circular venturi were used to generate cavitation in HC reactor. The process parameters such as initial dye concentration, solution pH, operating inlet pressure, and cavitation number were investigated in detail to evaluate their effects on the decolorization efficiency of Rh6G. Decolorization of Rh6G was marginally higher in the case of slit venturi as compared to circular venturi. The kinetic study showed that decolorization and mineralization of the dye fitted first-order kinetics. The loadings of H 2 O 2 and ozone have been optimized to intensify the decolorization and mineralization efficiency of Rh6G using HC. Nearly 54% decolorization of Rh6G was obtained using a combination of HC and H 2 O 2 at a dye to H 2 O 2 molar ratio of 1:30. The combination of HC with ozone resulted in 100% decolorization in almost 5-10min of processing time depending upon the initial dye concentration. To quantify the extent of mineralization, total organic carbon (TOC) analysis was also performed using various processes and almost 84% TOC removal was obtained using HC coupled with 3g/h of ozone. The degradation by-products formed during the complete degradation process were qualitatively identified by liquid chromatography-mass spectrometry (LC-MS) and a detailed degradation pathway has been proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

Sequestration of dyes from artificially prepared textile effluent using RSM-CCD optimized hybrid backbone based adsorbent-kinetic and equilibrium studies.

PubMed

Sukriti; Sharma, Jitender; Chadha, Amritpal Singh; Pruthi, Vaishali; Anand, Prerna; Bhatia, Jaspreet; Kaith, B S

2017-04-01

Present work reports the synthesis of semi-Interpenetrating Network Polymer (semi-IPN) using Gelatin-Gum xanthan hybrid backbone and polyvinyl alcohol in presence of l-tartaric acid and ammonium persulphate as the crosslinker-initiator system. Reaction parameters were optimized with Response Surface Methodology (RSM) in order to maximize the percent gel fraction of the synthesized sample. Polyvinyl alcohol, l-Tartaric acid, ammonium persulphate, reaction temperature, time and pH of the reaction medium were found to make an impact on the percentage gel fraction obtained. Incorporation of polyvinyl alcohol chains onto hybrid backbone and crosslinking between the different polymer chains were confirmed through techniques like FTIR, SEM-EDX and XRD. Semi-IPN was found to be very efficient in the removal of cationic dyes rhodamine-B (70%) and auramine-O (63%) from a mixture with an adsorbent dose of 700 mg, initial concentration of rhodamine-B 6 mgL -1 and auramine-O 26 mgL -1 , at an time interval of 22-25 h and 30 °C temp. Further to determine the nature of adsorption Langmuir and Freundlich adsorption isotherm models were studied and it was found that Langmuir adsorption isotherm was the best fit model for the removal of mixture of dyes. Kinetic studies for the sorption of dyes favored the reaction mechanism to occur via a pseudo second order pathway with R 2 value about 0.99. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kinetics of zero-valent iron reductive transformation of the anthraquinone dye Reactive Blue 4.

PubMed

Epolito, William J; Yang, Hanbae; Bottomley, Lawrence A; Pavlostathis, Spyros G

2008-12-30

The effect of operational conditions and initial dye concentration on the reductive transformation (decolorization) of the textile dye Reactive Blue 4 (RB4) using zero-valent iron (ZVI) filings was evaluated in batch assays. The decolorization rate increased with decreasing pH and increasing temperature, mixing intensity, and addition of salt (100gL(-1) NaCl) and base (3gL(-1) Na2CO3 and 1gL(-1) NaOH), conditions typical of textile reactive dyebaths. ZVI RB4 decolorization kinetics at a single initial dye concentration were evaluated using a pseudo first-order model. Under dyebath conditions and at an initial RB4 concentration of 1000mgL(-1), the pseudo first-order rate constant (kobs) was 0.029+/-0.006h(-1), corresponding to a half-life of 24.2h and a ZVI surface area-normalized rate constant (kSA) of 2.9x10(-4)Lm(-2)h(-1). However, as the initial dye concentration increased, the kobs decreased, suggesting saturation of ZVI surface reactive sites. Non-linear regression of initial decolorization rate values as a function of initial dye concentration, based on a reactive sites saturation model, resulted in a maximum decolorization rate (Vm) of 720+/-88mgL(-1)h(-1) and a half-saturation constant (K) of 1299+/-273mgL(-1). Decolorization of RB4 via a reductive transformation, which was essentially irreversible (2-5% re-oxidation), is believed to be the dominant decolorization mechanism. However, some degree of RB4 irreversible sorption cannot be completely discounted. The results of this study show that ZVI treatment is a promising technology for the decolorization of commercial, anthraquinone-bearing, spent reactive dyebaths.

Long-Time Plasma Membrane Imaging Based on a Two-Step Synergistic Cell Surface Modification Strategy.

PubMed

Jia, Hao-Ran; Wang, Hong-Yin; Yu, Zhi-Wu; Chen, Zhan; Wu, Fu-Gen

2016-03-16

Long-time stable plasma membrane imaging is difficult due to the fast cellular internalization of fluorescent dyes and the quick detachment of the dyes from the membrane. In this study, we developed a two-step synergistic cell surface modification and labeling strategy to realize long-time plasma membrane imaging. Initially, a multisite plasma membrane anchoring reagent, glycol chitosan-10% PEG2000 cholesterol-10% biotin (abbreviated as "GC-Chol-Biotin"), was incubated with cells to modify the plasma membranes with biotin groups with the assistance of the membrane anchoring ability of cholesterol moieties. Fluorescein isothiocyanate (FITC)-conjugated avidin was then introduced to achieve the fluorescence-labeled plasma membranes based on the supramolecular recognition between biotin and avidin. This strategy achieved stable plasma membrane imaging for up to 8 h without substantial internalization of the dyes, and avoided the quick fluorescence loss caused by the detachment of dyes from plasma membranes. We have also demonstrated that the imaging performance of our staining strategy far surpassed that of current commercial plasma membrane imaging reagents such as DiD and CellMask. Furthermore, the photodynamic damage of plasma membranes caused by a photosensitizer, Chlorin e6 (Ce6), was tracked in real time for 5 h during continuous laser irradiation. Plasma membrane behaviors including cell shrinkage, membrane blebbing, and plasma membrane vesiculation could be dynamically recorded. Therefore, the imaging strategy developed in this work may provide a novel platform to investigate plasma membrane behaviors over a relatively long time period.

Wastewater remediation by TiO2-impregnated chitosan nano-grafts exhibited dual functionality: High adsorptivity and solar-assisted self-cleaning.

PubMed

Essawy, Amr A; Sayyah, S M; El-Nggar, A M

2017-08-01

This work provides a very infrequent and unique avenue of a novel bio-based nanografted polymeric composites achieving encouraging results in green management of dye contaminants in wastewater. A chitosan-grafted-polyN-Methylaniline (Ch-g-PNMANI) and chitosan-grafted-polyN-Methylaniline imprinted TiO 2 nanocomposites (Ch-g-PNMANI/TiO 2 ) were prepared and efficiently applied in wastewater remediation. The nanocomposites were characterized by FT-IR spectroscopy, X-ray diffraction, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy and Brunauer-Emmett-Teller surface area (BET) measurements. The prepared composites exhibit higher adsorptivity in removing remazol red RB-133 (RR RB-133) dye compared to other adsorbents reported in literature. The effects of TiO 2 loadings, initial dye concentration, contact time, and pH on dye adsorption were investigated. The maximum adsorption of dye was found at low pH values. Furthermore, Ch-g-PNMANI/TiO 2 of the optimum TiO 2 loading has higher adsorption capacity (116.3mg/g) than the pristine Ch-g-PNMANI (108.7mg/g). Moreover, the prepared adsorbents are photoactive under sunlight-irradiation. The study addresses a nanocomposite of considerable adsorption and in the same time has the fastest self-cleaning photoactivity (t 1/2 =31.5min.) under sunlight irradiation where a plausible photodegradation mechanism was proposed. Interestingly, the presented photoactive adsorbents are still effective in removing dye after five adsorption/sunlight-assisted self-cleaning photoregeneration cycles and therefore, they can be potentially applied to the rapid, "green" and low-cost remediation of RR RB-133 enriched industrial printing and dyeing wastewater. Copyright © 2017 Elsevier B.V. All rights reserved.

Application of experimental design and derivative spectrophotometry methods in optimization and analysis of biosorption of binary mixtures of basic dyes from aqueous solutions.

PubMed

Asfaram, Arash; Ghaedi, Mehrorang; Ghezelbash, Gholam Reza; Pepe, Francesco

2017-05-01

Simultaneous biosorption of malachite green (MG) and crystal violet (CV) on biosorbent Yarrowia lipolytica ISF7 was studied. An appropriate derivative spectrophotometry technique was used to evaluate the concentration of each dye in binary solutions, despite significant interferences in visible light absorbances. The effects of pH, temperature, growth time, initial MG and CV concentration in batch experiments were assessed using Design of Experiment (DOE) according to central composite second order response surface methodology (RSM). The analysis showed that the greatest biosorption efficiency (>99% for both dyes) can be obtained at pH 7.0, T=28°C, 24h mixing and 20mgL -1 initial concentrations for both MG and CV dyes. The quadratic constructed equation ability for fitting experimental data is judged based on criterions like R 2 values, significant p and lack-of-fit value strongly confirm its high adequacy and applicability for prediction of revel behavior of the system under study. The proposed model showed very high correlation coefficients (R 2 =0.9997 for CV and R 2 =0.9989 for MG), while supported by closeness of predicted and experimental value. A kinetic analysis was carried out, showing that for both dyes a pseudo-second order kinetic model adequately describes the available data. The Langmuir isotherm model in single and binary components has better performance for description of dyes biosorption with maximum monolayer biosorption capacity of 59.4 and 62.7mgg -1 in single component and 46.4 and 50.0mgg -1 for CV and MB in binary components, respectively. The surface structure of biosorbents and the possible biosorbents-dyes interactions between were also evaluated by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The values of thermodynamic parameters including ΔG° and ΔH° strongly confirm which method is spontaneous and endothermic. Copyright © 2017. Published by Elsevier Inc.

A Comparative Study of the Adsorption of Methylene Blue onto Synthesized Nanoscale Zero-Valent Iron-Bamboo and Manganese-Bamboo Composites

PubMed Central

Shaibu, Solomon E.; Adekola, Folahan A.; Adegoke, Halimat I.; Ayanda, Olushola S.

2014-01-01

In this study, bamboo impregnated with nanoscale zero-valent iron (nZVI) and nanoscale manganese (nMn) were prepared by the aqueous phase borohydride reduction method and characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and PIXE analysis. The synthesized nMn-bamboo and nZVI-bamboo composites were subsequently applied to the sorption of methylene blue (MB) dye from aqueous solution. The adsorption of MB dye was investigated under various experimental conditions such as pH, contact time, initial concentration of MB dye and adsorbent dosage. The results showed that the synthesized nZVI-bamboo composite was more effective than nMn-bamboo composite in terms of higher MB dye adsorption capacity of 322.5 mg/g compared to 263.5 mg/g of nMn-bamboo composite. At a concentration of 140 mg/L MB dye, 0.02 g of nZVI-bamboo and nMn-bamboo composites resulted in 79.6% and 78.3% removal, respectively, at 165 rpm, contact time of 120 min and at a solution pH of 7.6. The equilibrium data was best represented by Freundlich isotherm model and the pseudo-second order kinetic model better explained the kinetic data for both nZVI-bamboo and nMn-bamboo composites. PMID:28788688

Effect of electron beam irradiation on the structural properties of poly(vinyl alcohol) formulations with triphenyl tetrazolium chloride dye (TTC)

NASA Astrophysics Data System (ADS)

Ali, Z. I.; Said, Hossam M.; Ali, H. E.

2006-01-01

Films of poly(vinyl alcohol) (PVA) composites with triphenyl tetrazolium chloride (TTC) dye were prepared and exposed to various radiation doses delivered by accelerated electrons. The results showed that at a low dose of 50 kGy, the colour difference (Δ E*) of PVA/TTC films was increased by ˜10 times of the initial value. However, the change in colour differences did not go systematically with increasing the TTC content, in which the composite with 1.5 wt% displayed higher value than that with 3.5 wt%. The differential scanning calorimetry (DSC) showed that the presence of the TTC dye caused a depression in the melting point ( Tm) and heat of fusion (Δ Hf) of the PVA bulk polymer. However, the thermogravimetric analysis (TGA) showed that the presence of the TTC dye improved the thermal stability of PVA. Also, the tensile strength at break of PVA/TTC composites was improved after electron beam irradiation.

Removal of Direct Red 12B by garlic peel as a cheap adsorbent: Kinetics, thermodynamic and equilibrium isotherms study of removal

NASA Astrophysics Data System (ADS)

Asfaram, A.; Fathi, M. R.; Khodadoust, S.; Naraki, M.

2014-06-01

The removal of dyes from industrial waste is very important from health and hygiene point of view and for environmental protection. In this work, efficiency and performance of garlic peel (GP) adsorbent for the removal of Direct Red 12B (DR12B) from wastewater was investigated. The influence of variables including pH, concentration of the dye and amount of adsorbent, particle size, contact time and temperature on the dye removal has been investigated. It was observed that the pseudo-second-order kinetic model fits better with good correlation coefficient and the equilibrium data fitted well with the Langmuir model. More than 99% removal efficiency was obtained within 25 min at adsorbent dose of 0.2 g per 50 ml for initial dye concentration of 50 mg L-1. Calculation of various thermodynamic parameters such as, Gibb's free energy, entropy and enthalpy of the on-going adsorption process indicate feasibility and endothermic nature of DR12B adsorption.

Mechanical and dye adsorption properties of graphene oxide/chitosan composite fibers prepared by wet spinning.

PubMed

Li, Yanhui; Sun, Jiankun; Du, Qiuju; Zhang, Luhui; Yang, Xiaoxia; Wu, Shaoling; Xia, Yanzhi; Wang, Zonghua; Xia, Linhua; Cao, Anyuan

2014-02-15

Graphene oxide/chitosan composite fibers were prepared by a wet spinning method, and their mechanical properties were investigated. Experimental results showed that the introduction of graphene oxide at 4 wt% loading can improve the tensile strengths of chitosan fibers. Batch adsorption experiments were carried out to study the effect of various parameters, such as the initial pH value, adsorbent dosage, contact time and temperature on adsorption of fuchsin acid dye. The Langmuir model was used to fit the experimental data of adsorption isotherm, and kinetic studies showed that the adsorption data followed the pseudo-second order model. Thermodynamic studies indicated that the adsorption of fuchsin acid dye on graphene oxide/chitosan fibers was a spontaneous and exothermic process. Our results indicate that the graphene oxide/chitosan fibers have excellent mechanical properties and can serve as a promising adsorbent for the removal of dyes from aqueous solutions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Protonation-Gated Dual Photochromism of a Chromene-Styryl Dye Hybrid.

PubMed

Berdnikova, Daria V; Paululat, Thomas; Jonusauskas, Gediminas; Peregudova, Svetlana M; Fedorova, Olga A

2017-10-20

A novel hybrid bisphotochromic system involving a chromene residue and a styryl dye fragment is described. Initially, the compound shows almost no photochromism due to intramolecular energy and electron transfer between the chromophores. Protonation of the hybrid system blocks the transfer processes and unlocks a dual photochromic activity that includes ring opening of the chromene fragment and E-Z-isomerization of the styryl dye residue. Deprotonation of any photoinduced form resets the system to the initial photoinactive form.

Removal of methylene blue from aqueous solution by Artist's Bracket fungi: kinetic and equilibrium studies.

PubMed

Naghipour, Daryush; Taghavi, Kamran; Moslemzadeh, Mehrdad

2016-01-01

In this study, adsorption of methylene blue (MB) dye onto Artist's Bracket (AB) fungi was investigated in aqueous solution. Fourier transform infrared and scanning electron microscopy were used to investigate surface characteristic of AB fungi. Influence of operational parameters such as pH, contact time, biosorbent dosage, dye concentration, inorganic salts and temperature was studied on dye removal efficiency. With the increase of pH from 3 to 9, removal efficiency increased from 74.0% to 90.4%. Also, it reduced from 99.8% to 81.8% with increasing initial MB concentration from 25 mg L(-1) to 100 mg L(-1), whereas it increased from 54.7% to 98.7% and from 98.5% to 99.9% with increasing biosorbent dosage from 0.5 g L(-1) to 2 g L(-1) and with increasing temperature from 25 °C to 50 °C, respectively. Isotherm studies have shown adsorption of MB dye over the AB fungi had a better coefficient of determination (R(2)) of 0.98 for Langmuir isotherm. In addition, the maximum monolayer adsorption capacity (qm) was 100 mg g(-1). Also, the MB dye adsorption process followed pseudo-second-order kinetic. In general, AB fungi particles can be favorable for removal of MB dye from dye aqueous solution with natural pH and high temperature.

3D Oxidized Graphene Frameworks: An Efficient Adsorbent for Methylene Blue

NASA Astrophysics Data System (ADS)

Pandey, Abhishek; Deb, Madhurima; Tiwari, Shreya; Pawar, Pranav Bhagwan; Saxena, Sumit; Shukla, Shobha

2018-04-01

Extraordinary properties of graphene and its derivatives have found application in varied areas such as energy, electronics, optical devices and sensors, to name a few. Large surface area along with specialized functional groups make these materials attractive for removal of dye molecules in solution via adsorption. Industrial effluents contain large amounts of toxic chemicals resulting in pollution of water bodies, which pose environmental hazards in general. Here we report application of 3D oxidized graphene frameworks in the efficient removal of cationic dye molecules such as methylene blue via adsorption. Systematic parametric studies investigating the effect of the initial dye concentration, pH and contact time have been performed. Spectroscopic analysis of the filtrate suggests that tortuous paths in 3D oxidized graphene frameworks result in efficient removal of dye molecules due to enhanced interaction. The hydroxyl groups retained in these 3D oxidized graphene frameworks facilitate adsorption of the dye molecules while passing through the adsorbent. pH studies suggest that maximum removal efficiency for methylene blue was achieved at pH value of 9. The results suggest that these 3D oxidized graphene frameworks can be used for purification of large volumes of contaminated water from cationic dyes in waste water treatment plants.

Removal of anionic dye Congo red from aqueous solution by raw pine and acid-treated pine cone powder as adsorbent: equilibrium, thermodynamic, kinetics, mechanism and process design.

PubMed

Dawood, Sara; Sen, Tushar Kanti

2012-04-15

Pine cone a natural, low-cost agricultural by-product in Australia has been studied for its potential application as an adsorbent in its raw and hydrochloric acid modified form. Surface study of pine cone and treated pine cone was investigated using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The modification process leads to increases in the specific surface area and decreases mean particle sizes of acid-treated pine cone when compared to raw pine cone biomass. Batch adsorption experiments were performed to remove anionic dye Congo red from aqueous solution. It was found that the extent of Congo red adsorption by both raw pine cone biomass and acid-treated biomass increased with initial dye concentration, contact time, temperature but decreased with increasing solution pH and amount of adsorbent of the system. Overall, kinetic studies showed that the dye adsorption process followed pseudo-second-order kinetics based on pseudo-first-order and intra-particle diffusion models. The different kinetic parameters including rate constant, half-adsorption time, and diffusion coefficient were determined at different physico-chemical conditions. Equilibrium data were best represented by Freundlich isotherm model among Langmuir and Freundlich adsorption isotherm models. It was observed that the adsorption was pH dependent and the maximum adsorption of 32.65 mg/g occurred at pH of 3.55 for an initial dye concentration of 20 ppm by raw pine cone, whereas for acid-treated pine cone the maximum adsorption of 40.19 mg/g for the same experimental conditions. Freundlich constant 'n' also indicated favourable adsorption. Thermodynamic parameters such as ∆G(0), ∆H(0), and ∆S(0) were calculated. A single-stage batch absorber design for the Congo red adsorption onto pine cone biomass also presented based on the Freundlich isotherm model equation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Synthesized TiO2/ZSM-5 composites used for the photocatalytic degradation of azo dye: Intermediates, reaction pathway, mechanism and bio-toxicity

NASA Astrophysics Data System (ADS)

Zhou, Kefu; Hu, Xin-Yan; Chen, Bor-Yann; Hsueh, Chung-Chuan; Zhang, Qian; Wang, Jiajie; Lin, Yu-Jung; Chang, Chang-Tang

2016-10-01

In this study, a one-step solid dispersion method was used to synthesize titanium dioxide (TiO2)/Zeolite Socony Mobil-5 (ZSM-5) composites with substantially reduced time and energy consumption. A degradation efficiency of more than 95% was achieved within 10 min using 50% PTZ (synthesized TiO2/ZSM-5 composites with TiO2 contents of 50 wt% loaded on ZSM-5) at pH 7 and 25 °C. The possible degradation pathway of azo-dye Reactive Black 5 (RB5) was investigated using gas chromatography-mass spectrometry and ion chromatography (IC). The bonds between the N atoms and naphthalene groups are likely attacked first and cleaved by hydroxyl radicals, ultimately resulting in the decolorization and mineralization of the azo dye. A comparative assessment of the characteristics of abiotic and biotic dye decolorization was completed. In addition, the toxicity effects of the degradation intermediates of azo-dye RB5 on cellular respiratory activity were analyzed. The bio-toxicity results showed that the decay rate constants of CO2 production from the azo-dye RB5 samples at different degradation times increased initially and subsequently decreased, indicating that intermediates of higher toxicity could adhere to the catalyst surface and gradually destroyed by further photocatalytic oxidation. Additionally, EDTA (hole scavengers) and t-BuOH (radical scavengers) were used to detect the main active oxidative species in the system. The results showed that the hydroxyl radicals are the main oxidation species in the photocatalytic process.

Influence of PCR reagents on DNA polymerase extension rates measured on real-time PCR instruments.

PubMed

Montgomery, Jesse L; Wittwer, Carl T

2014-02-01

Radioactive DNA polymerase activity methods are cumbersome and do not provide initial extension rates. A simple extension rate assay would enable study of basic assumptions about PCR and define the limits of rapid PCR. A continuous assay that monitors DNA polymerase extension using noncovalent DNA dyes on common real-time PCR instruments was developed. Extension rates were measured in nucleotides per second per molecule of polymerase. To initiate the reaction, a nucleotide analog was heat activated at 95 °C for 5 min, the temperature decreased to 75 °C, and fluorescence monitored until substrate exhaustion in 30-90 min. The assay was linear with time for over 40% of the reaction and for polymerase concentrations over a 100-fold range (1-100 pmol/L). Extension rates decreased continuously with increasing monovalent cation concentrations (lithium, sodium, potassium, cesium, and ammonium). Melting-temperature depressors had variable effects. DMSO increased rates up to 33%, whereas glycerol had little effect. Betaine, formamide, and 1,2-propanediol decreased rates with increasing concentrations. Four common noncovalent DNA dyes inhibited polymerase extension. Heat-activated nucleotide analogs were 92% activated after 5 min, and hot start DNA polymerases were 73%-90% activated after 20 min. Simple DNA extension rate assays can be performed on real-time PCR instruments. Activity is decreased by monovalent cations, DNA dyes, and most melting temperature depressors. Rational inclusion of PCR components on the basis of their effects on polymerase extension is likely to be useful in PCR, particularly rapid-cycle or fast PCR.

Synergistic effect of manganese dioxide and diatomite for fast decolorization and high removal capacity of methyl orange.

PubMed

Peng, Hui Hua; Chen, Jie; Jiang, De Yi; Li, Min; Feng, Li; Losic, Dusan; Dong, Fan; Zhang, Yu Xin

2016-12-15

MnO 2 nanostructures with two different morphologies (nanowires and nanosheets) were uniformly deposited on diatomite via a one-pot hydrothermal method. The fast decolorization and high removal capacity for anionic dye-MO over synthesized composites had been clarified. The results revealed that the equilibrium time was shortened to as low as 10-30min, and the maximum adsorption capacities were 325mgg -1 and 420mgg -1 for nanowires and nanosheets composites, respectively, under the condition of initial pH 3 and ambient temperature. Indeed, the proposed decolorization mechanism was considered to be simultaneous multi-processes during the dye removal, including physical, physicochemical and chemical process. In principle, well-controlled cost-effective composites have promising ability to remove anionic dye pollutants for environmental remediation. Copyright © 2016 Elsevier Inc. All rights reserved.

Selective Adsorption and Separation of Organic Dyes with Spherical Polyelectrolyte Brushes and Compressed Carbon Dioxide.

PubMed

Zhang, Rui; Yu, Zhenchuan; Wang, Lei; Shen, Qizhe; Hou, Xiaoyan; Guo, Xuhong; Wang, Junwei; Zhu, Xuedong; Yao, Yuan

2017-10-04

Dye-containing wastewater has caused serious environmental pollution. Herein, rationally designed spherical polyelectrolyte brushes (SPBs) with cationic charges, polystyrene-poly(2-aminoethylmethacrylate hydrochloride) (PS-PAEMH) as the absorbent, and compressed carbon dioxide as the antisolvent are proposed for the separation of the anionic dye eosin Y (EY) from a solution of mixed dyes. The adsorption behavior of EY onto PS-PAEMH was highly dependent on CO 2 pressure, contact time, and initial concentration. The maximum adsorption capacity of PS-PAEMH was 335.20 mg g -1 . FTIR and UV/Vis measurements proved that the electrostatic interactions between EY and PS-PAEMH played an important role in the absorbance process. The adsorption process fitted the pseudo-second-order kinetic model and Freundlich isotherm model very well. The combined dye and polymer brush could be easily separated through ion exchange by adding an aqueous solution of NaCl. Recovered PS-PAEMH retained a high adsorption capacity even after ten cycles of regeneration. This method provides a simple and effective way to separate ionic materials for environmental engineering. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recycling food waste to clean water: the use of a biodigester's residual liquid inoculum (RLI) to decolourise textile azo dyes.

PubMed

Maganha de Almeida, A C; Backhaus, J; Corso, C R

2018-01-01

A residual liquid inoculum (RLI) was used to decolourise solutions of Acid Yellow 25 (AY25) and Direct Violet 51 (DV51) azo dyes. The RLI was obtained through anaerobic digestion of food waste from a university restaurant. The concentration of bacteria in the RLI was 8.45 × 10 7 CFU mL -1 . Dye solutions (50 μg mL -1 ) were inoculated with the RLI (20% v/v) and incubated at room temperature. The decolourisation studies took place at microaerophilic and in-batch conditions and at pH = 2.50. Initially, the dyes were taken up from solution by biosorption; maximum colour removal was achieved after 3 hours of incubation, with 88.66% for AY25 and 77.65% of DV51. At prolonged incubation times (3-96 hours) decolourisation was mainly attributed to biodegradation of the azo solutions, with breakage of the azo bond, as detected by UV-VIS spectroscopy and Fourier transform infrared (FT-IR) analysis. Analysis of UV-VIS absorption rates of dyes showed, however, that AY25 was more readily biodegradable whereas DV51 was more recalcitrant to the action of the RLI.

[Induce of laccase from Trametes gallica and its degradation on neutral dyes and organophosphorus pesticides].

PubMed

Jing, De-Jun; Huang, Jian-Bo; Yang, Zhou-Ping; Hu, Rong; Cheng, Zi-Zhang; Huang, Qian-Ming

2011-12-01

The characteristics of the induction of laccase in Trametes gallica under different initial cultural pH, incubation time by different inducers were discussed, as well as the effects of temperature, pH and time on laccase degradation of six dyes and four organophosphors. The results showed that RB-bright blue, ABTS and o-toluidine affected the production of laccase at different levels, and ABTS was the best inductive agent in our test conditions, whose optimal initial pH and incubation time were 4.0 and 13 days, respectively. The appropriate reaction temperature of the laccase produced was 38 degrees C, and it got a good stability, for it could retain 78.6% of the enzyme activity after 20 min holding at 40 degrees C. Mediated by ABTS, the optimal temperature for laccase to degrade the six types of neutral dyes could be divided into two cases, that was 30 degrees C (neutral black, neutral bordeaux, neutral pink, methyl orange) and 60 degrees C (neutral dark yellow, cresol red), the optimal pH were 6.0 (neutral black), 2.0 (neutral bordeaux, neutral pink) and 4.0 (methyl orange, neutral dark yellow, cresol red), respectively, while the optimal times separately were 6 h (methyl orange, neutral dark yellow, cresol red), 12 h (neutral pink) and 24 h (neutral bordeaux). And using the same inductive agent, the best temperature for laccase to degrade dimethoate, chlorpyrifos, trichlorfon and parathion-pyridazine was 25 degrees C, the suitable time was 9 h, and the optimal pH was 10.0 for dimethoate, chlorpyrifos and parathion-pyridazine, and 8.0 for trichlorfon.

Removal of Direct N Blue-106 from artificial textile dye effluent using activated carbon from orange peel: adsorption isotherm and kinetic studies.

PubMed

Khaled, Azza; El Nemr, Ahmed; El-Sikaily, Amany; Abdelwahab, Ola

2009-06-15

The purpose of this study is to suggest an efficient process, which does not require a huge investment for the removal of direct dye from wastewater. Activated carbon developed from agricultural waste material was characterized and utilized for the removal of Direct Navy Blue 106 (DNB-106) from wastewater. Systematic studies on DNB-106 adsorption equilibrium and kinetics by low-cost activated carbons were carried out. Adsorption studies were carried out at different initial concentrations of DNB-106 (50, 75, 100, 125 and 150 mg l(-1)), contact time (5-180 min), pH (2.0, 3.0, 4.7, 6.3, 7.2, 8.0, 10.3 and 12.7) and sorbent doses (2.0, 4.0 and 6.0 g l(-1)). Both Langmuir and Freundlich models fitted the adsorption data quite reasonably (R(2)>97). The maximum adsorption capacity was 107.53 mg g(-1) for 150 mg l(-1) of DNB-106 concentration and 2 g l(-1) carbon concentration. Various mechanisms were established for DNB-106 adsorption on developed adsorbents. The kinetic studies were conducted to delineate the effect of initial dye concentration, contact time and solid to liquid concentration. The developed carbon might be successfully used for the removal of DNB-106 from liquid industrial wastes.

Sorption and desorption studies of a reactive azo dye on effective disposal of redundant material.

PubMed

Çelekli, Abuzer; Bozkurt, Hüseyin

2013-07-01

The effective disposal of redundant elephant dung (ED) is important for environmental protection and utilization of resource. The aim of this study was to remove a toxic-azo dye, Reactive Red (RR) 120, using this relatively cheap material as a new adsorbent. The FTIR-ATR spectra of ED powders before and after the sorption of RR 120 and zero point charge (pHzpc) of ED were determined. The sorption capacity of ED for removing of RR 120 were carried out as functions of particle size, adsorbent dose, pH, temperature, ionic strength, initial dye concentration, and contact time. Sorption isotherm, kinetic, activation energy, thermodynamic, and desorption parameters of RR 120 on ED were studied. The sorption process was found to be dependent on particle size, adsorbent dose, pH, temperature, ionic strength, initial dye concentration, and contact time. FTIR-ATR spectroscopy indicated that amine and amide groups have significant role on the sorption of RR 120 on ED. The pHzpc of ED was found to be 7.3. Sorption kinetic of RR 120 on ED was well described by sigmoidal Logistic model. The Langmuir isotherm was well fitted to the equilibrium data. The maximum sorption capacity was 95.71 mg g(-1). The sorption of RR 120 on ED was mainly physical and exothermic according to results of D-R isotherm, Arrhenius equation, thermodynamic, and desorption studies. The thermodynamic parameters showed that this process was feasible and spontaneous. This study showed that ED as a low-cost adsorbent had a great potential for the removal of RR 120 as an alternative eco-friendly process.

Adsorption of basic dyes on granular activated carbon and natural zeolite.

PubMed

Meshko, V; Markovska, L; Mincheva, M; Rodrigues, A E

2001-10-01

The adsorption of basic dyes from aqueous solution onto granular activated carbon and natural zeolite has been studied using an agitated batch adsorber. The influence of agitation, initial dye concentration and adsorbent mass has been studied. The parameters of Langmuir and Freundlich adsorption isotherms have been determined using the adsorption data. Homogeneous diffusion model (solid diffusion) combined with external mass transfer resistance is proposed for the kinetic investigation. The dependence of solid diffusion coefficient on initial concentration and mass adsorbent is represented by the simple empirical equations.

Adsorption of dissolved Reactive red dye from aqueous phase onto activated carbon prepared from agricultural waste.

PubMed

Senthilkumaar, S; Kalaamani, P; Porkodi, K; Varadarajan, P R; Subburaam, C V

2006-09-01

The adsorption of Reactive red dye (RR) onto Coconut tree flower carbon (CFC) and Jute fibre carbon (JFC) from aqueous solution was investigated. Adsorption studies were carried out at different initial dye concentrations, initial solution pH and adsorbent doses. The kinetic studies were also conducted; the adsorption of Reactive red onto CFC and JFC followed pseudosecond-order rate equation. The effective diffusion coefficient was evaluated to establish the film diffusion mechanism. Quantitative removal of Reactive red dye was achieved at strongly acidic conditions for both the carbons studied. The adsorption isotherm data were fitted well to Langmuir isotherm and the adsorption capacity were found to be 181.9 and 200 mg/g for CFC and JFC, respectively. The overall rate of dye adsorption appeared to be controlled by chemisorption, in this case in accordance with poor desorption studies.

Initiator system in holographic photopolymer materials

NASA Astrophysics Data System (ADS)

Ortuño, M.; Fernández, E.; Fuentes, R.; Gallego, S.; Márquez, A.

2010-05-01

The photopolymers with a hydrophilic matrix as poly(vinyl alcohol), PVA, are versatile holographic recording materials in hologram recording experiments. They use water as solvent and they can be made in layers with several thickness. One of the photopolymers more used is composed of acrylamide as polymerizable monomer, PVA and water as binder. The pair: triethanolamine, TEA, and the dye yellowish eosin, YE, is widely used as initiator system due to its high sensitivity and efficiency. TEA is the radical initiator more used with dyes derived from fluorescein as YE because they can generate a radical by redox reaction under dye excitation by light. The dye is bleached in this process because is decomposed in the photoinitiation reaction. The ethylenediaminetetraacetic acid EDTA has a molecular structure very similar to TEA and therefore could replace it in this kind of photopolymers. The 4,4' azo-bis-(4-cyanopentanoic acid), ACPA, is a radical initiator that is soluble in water and usually used in polymerizations in solution with thermal initiation. In this work, we use EDTA and ACPA in order to check their properties as radical initiator in the photochemical reaction that takes place inside the photopolymer while a hologram is being recorded. We will compare the results obtained with those derived from TEA and will evaluate the possibilities for these substances.

Ultrasonic-assisted dyeing of Nylon-6 nanofibers.

PubMed

Jatoi, Abdul Wahab; Ahmed, Farooq; Khatri, Muzamil; Tanwari, Anwaruddin; Khatri, Zeeshan; Lee, Hoik; Kim, Ick Soo

2017-11-01

We first time report ultrasonic dyeing of the Nylon 6 nanofibers with two disperse dyes CI Disperse blue 56 and CI Disperse Red 167:1 by utilising ultrasonic energy during dyeing process. The Nylon 6 nanofibers were fabricated via electrospinning and dyed via batchwise method with and without sonication. Results revealed that ultrasonic dyeing produce higher color yield (K/S values) and substantially reduces dyeing time from 60min for conventional dyeing to 30min can be attributed to breakage of dye aggregate, transient cavitation near nanofiber surface and mass transfer within/between nanofibers. Color fastness results exhibited good to very good dye fixation. SEM images exhibit insignificant effect of sonication on morphology of the nanofibers. Our research results demonstrate ultrasonic dyeing as a better dyeing technique for Nylon 6 nanofibers with higher color yield and substantially reduced dyeing time. Copyright © 2017 Elsevier B.V. All rights reserved.

Process for separating and recovering an anionic dye from an aqueous solution

DOEpatents

Rogers, Robin; Horwitz, E. Philip; Bond, Andrew H.

1998-01-01

A solid/liquid phase process for the separation and recovery of an anionic dye from an aqueous solution is disclosed. The solid phase comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the anionic dye molecules are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt. After contact between the aqueous solution and separation particles, the anionic dye is bound to the particles. The bound anionic dye molecules are freed from the separation particles by contacting the anionic dye-bound particles with an aqueous solution that does not contain a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt to form an aqueous anionic dye solution whose anionic dye concentration is preferably higher than that of the initial dye-containing solution.

Treatment of an azo dye effluent by peroxi-coagulation and its comparison to traditional electrochemical advanced processes.

PubMed

do Vale-Júnior, Edilson; da Silva, Djalma R; Fajardo, Ana S; Martínez-Huitle, Carlos A

2018-08-01

Peroxi-coagulation (PC) is an interesting new process that has not been widely studied in the literature. This work presents the application of this technology to treat an azo dye synthetic effluent, studying the effect of different parameters including initial pH, current density (j), initial dye concentration and supporting electrolyte. The two former variables significantly affected the colour removal of the wastewater, followed by the initial dye concentration and the kind of electrolyte, in a lesser extent. The optimum operating conditions achieved were initial pH of 3.0, j = 33.3 mA cm -2 , 100 mg L -1 of methyl orange (MO) and Na 2 SO 4 as supporting electrolyte. The performance of PC was also compared to other electrochemical advanced processes, under similar experimental conditions. Results indicate that the kinetic decay of the MO increases in the following order: electrocoagulation (EC) < electrochemical oxidation (EO) with electrogenerated H 2 O 2 < PC < electro-Fenton (EF). This behaviour is given to the high oxidant character of the homogenous OH radicals generated by EF and PC approaches. The EO process with production of H 2 O 2 (EO-H 2 O 2 ) is limited by mass transport and the EC, as a separation method, takes longer times to achieve similar removal results. Energy requirements about 0.06 kWh g COD -1 , 0.09 kWh g COD -1 , 0.7 kWh g COD -1 and 0.1 kWh g COD -1 were achieved for PC, EF, EO-H 2 O 2 and EC, respectively. Degradation intermediates were monitored and carboxylic acids were detected for PC and EF processes, being rapidly removed by the former technology. PC emerges as a promising and competitive alternative for wastewaters depollution, among other oxidative approaches. Copyright © 2018 Elsevier Ltd. All rights reserved.

Experimental and kinetic studies on methylene blue adsorption by coir pith carbon.

PubMed

Kavitha, D; Namasivayam, C

2007-01-01

Varying the parameters such as agitation time, dye concentration, adsorbent dose, pH and temperature carried out the potential feasibility of thermally activated coir pith carbon prepared from coconut husk for removal of methylene blue. Greater percentage of dye was removed with decrease in the initial concentration of dye and increase in amount of adsorbent used. Kinetic study showed that the adsorption of dye on coir pith carbon was a gradual process. Lagergren first-order, second-order, intra particle diffusion model and Bangham were used to fit the experimental data. Equilibrium isotherms were analysed by Langmuir, Freundlich, Dubnin-Radushkevich, and Tempkin isotherm. The adsorption capacity was found to be 5.87 mg/g by Langmuir isotherm for the particle size 250-500 microm. The equilibrium time was found to be 30 and 60 min for 10 and 20 mg/L and 100 min for 30, 40 mg/L dye concentrations, respectively. A maximum removal of 97% was obtained at natural pH 6.9 for an adsorbent dose of 100 mg/50 mL and 100% removal was obtained for an adsorbent dose of 600 mg/50 mL of 10 mg/L dye concentration. The pH effect and desorption studies suggest that chemisorption might be the major mode of the adsorption process. The change in entropy (DeltaS0) and heat of adsorption (DeltaH0) of coir pith carbon was estimated as 117.20 J/mol/K and 30.88 kJ/mol, respectively. The high negative value of change in Gibbs free energy indicates the feasible and spontaneous adsorption of methylene blue on coir pith carbon.

Biosorption and biodegradation of a sulfur dye in high-strength dyeing wastewater by Acidithiobacillus thiooxidans.

PubMed

Nguyen, Thai Anh; Fu, Chun-Chieh; Juang, Ruey-Shin

2016-11-01

The ability of the bacterial strain Acidithiobacillus thiooxidans to remove sulfur blue 15 (SB15) dye from water samples was examined. This bacterium could not only oxidize sulfur compounds to sulfuric acid but also promote the attachment of the cells to the surface of sulfidic particles, therefore serving as an efficient biosorbent. The biosorption isotherms were better described by the Langmuir equation than by the Freundlich or Dubinin-Radushkevich equation. Also, the biosorption process followed the pseudo-second-order kinetics. At pH 8.3 and SB15 concentrations up to 2000 mg L(-1) in the biomass/mineral salt solution, the dye removal and decolorization were 87.5% and 91.4%, respectively, following the biosorption process. Biodegradation was proposed as a subsequent process for the remaining dye (250-350 mg L(-1)). A central composite design was used to analyze independent variables in the response surface methodology study. Under the optimal conditions (i.e., initial dye concentration of 300 mg L(-1), initial biomass concentration of 1.0 g L(-1), initial pH of 11.7, and yeast extract dose of 60 mg L(-1)), up to 50% of SB15 was removed after 4 days of biodegradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Adsorptive performance of MOF nanocomposite for methylene blue and malachite green dyes: Kinetics, isotherm and mechanism.

PubMed

Alqadami, Ayoub Abdullah; Naushad, Mu; Alothman, Z A; Ahamad, Tansir

2018-06-06

In the present study, Fe 3 O 4 @AMCA-MIL-53(Al) nanocomposite was utilized for the adsorptive removal of highly toxic MB and MG dyes from aqueous environment. The batch adsorption tests were performed at different contact time, pH, Fe 3 O 4 @AMCA-MIL-53(Al) dose, initial concentration of dyes and temperature. The maximum adsorption capacity of MB and MG dyes onto of Fe 3 O 4 @AMCA-MIL-53(Al) using Langmuir equation was 1.02 and 0.90 m mol/g, respectively. The isotherm and kinetic studies revealed that adsorption data were well fitted to Langmuir isotherm and pseudo-first-order kinetics models. Various thermodynamic parameters were also calculated and interpreted. The positive and negative values of ΔH° and ΔG° indicated that the adsorption was endothermic and spontaneous, respectively. The adsorptive binding of MB and MG on Fe 3 O 4 @AMCA-MIL53(Al) nanocomposite was directed by carboxylate and amide groups through electrostatic interaction, π-π interaction and hydrogen bonding. The desorption of both dyes from Fe 3 O 4 @AMCA-MIL-53(Al) was also performed using mixed solution of 0.01 M HCl/ethanol. Thus, we conclude that the Fe 3 O 4 @AMCA-MIL-53(Al) was an outstanding material for the removal of dyes from aqueous environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

[The decolorization and biodegrading metabolism of azo dyes by Pseudomonas S-42].

PubMed

Liu, Z P; Yang, H F

1989-12-01

Pseudomonas S-42 was capable of decolorizing azo dyes such as Diamira Brilliant Orange RR(DBO-RR), Direct Brown M (DBM), Eriochrome Brown R(EBR) and so on. The cell suspension, cell-free extract and purified enzyme of Pseud. S-42 could decolorize azo dyes under similar conditions: the optimum pH and temperature laid 7.0 and 37 degrees C respectively. The efficiencies of decolorizing of DBO-RR, DBM, EBR by intact cells stood more than 90%. When the cell concentration was 15 mg(wet)/ml and the reaction time was 5 hours, the decolorizing activity for above three azo dyes by intact cells were 1.75, 2.4, 0.95 micrograms dye/mg cell, respectively. Cell-free extract and purified enzyme could well express the decolorizing activity only under the anaerobic condition and added NADH. Purified enzyme belongs to azoreductase, its molecular weight is about 34,000-2000 daltons, and its Vmax and Km for DBO-RR are 13 mumol.mg protein-1.min-1 and 54 mumol/L. The results of the detection of the biodegrading products of DBO-RR by spectrophotometric and NaNO2 reactional methods showed that the biodegradation of azo dyes was initiated by the reduction cleavage of azo bonds. It was hypothesized that biodegrading metabolism pathway of DBO-RR by Pseudomonas S-42.

Simultaneous ultrasound-assisted ternary adsorption of dyes onto copper-doped zinc sulfide nanoparticles loaded on activated carbon: optimization by response surface methodology.

PubMed

Asfaram, Arash; Ghaedi, Mehrorang; Hajati, Shaaker; Goudarzi, Alireza; Bazrafshan, Ali Akbar

2015-06-15

The simultaneous and competitive ultrasound-assisted removal of Auramine-O (AO), Erythrosine (Er) and Methylene Blue (MB) from aqueous solutions were rapidly performed onto copper-doped zinc sulfide nanoparticles loaded on activated carbon (ZnS:Cu-NP-AC). ZnS:Cu nanoparticles were studied by FESEM, XRD and TEM. First, the effect of pH was optimized in a one-at-a-time procedure. Then the dependency of dyes removal percentage in their ternary solution on the level and magnitude of variables such as sonication time, initial dyes concentrations and adsorbent dosage was fully investigated and optimized by central composite design (CCD) under response surface methodology (RSM) as well as by regarding desirability function (DF) as a good and general criterion. The good agreement found between experimental and predicted values supports and confirms the suitability of the present model to predict adsorption state. The applied ultrasound strongly enhanced mass transfer process and subsequently performance. Hence, a small amount of the adsorbent (0.04 g) was capable to remove high percentage of dyes, i.e. 100%, 99.6% and 100% for MB, AO and Er, respectively, in very short time (2.5 min). The experimental equilibrium data fitting to Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models showed that the Langmuir model applies well for the evaluation and description of the actual behavior of adsorption. The small amount of proposed adsorbent (0.015 g) was applicable for successful removal of dyes (RE>99.0%) in short time (2.5 min) with high adsorption capacity in single component system (123.5 mg g(-1) for MB, 123 mg g(-1) for AO and 84.5 mg g(-1) for Er). Kinetics evaluation of experiments at various time intervals reveals that adsorption processes can be well predicated and fitted by pseudo-second-order and Elovich models. Copyright © 2015 Elsevier B.V. All rights reserved.

Hemangiomas

MedlinePlus

... grow. The flash-lamp pulse dye, pump dye, diode, and sclero-laser are the primary lasers used ... go through several trials of dosing-tapering. The current protocol is to put them on the initial ...

Emulsion liquid membrane for textile dye removal: Stability study

NASA Astrophysics Data System (ADS)

Kusumastuti, Adhi; Syamwil, Rodia; Anis, Samsudin

2017-03-01

Although textile dyes is basically available in very low concentration; it should be removed due to the toxicity to human body and environment. Among the existing methods, emulsion liquid membrane (ELM) is a promising method by providing high interfacial area and the ability to remove a very low concentration of the solute. The optimal emulsions were produced using commercially supplied homogeniser. The drop size was measured by the aid of microscope and image J software. Initially, methylene blue in simulated wastewater was extracted using a stirrer. Methylene blue concentration was determined using spectrophotometer. The research obtained optimal emulsion at surfactant concentration of 4 wt. %, kerosene as diluent, emulsification time of 30 min, emulsification speed of 2000 rpm. The lowest membrane breakage and the longest stability time were about 0.11% and 150 min, respectively.

Preparation of Chitosan Coated Magnetic Hydroxyapatite Nanoparticles and Application for Adsorption of Reactive Blue 19 and Ni2+ Ions

PubMed Central

Nguyen, Van Cuong; Pho, Quoc Hue

2014-01-01

An adsorbent called chitosan coated magnetic hydroxyapatite nanoparticles (CS-MHAP) was prepared with the purpose of improvement for the removal of Ni2+ ions and textile dye by coprecipitation. Structure and properties of CS-MHAP were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). Weight percent of chitosan was investigated by thermal gravimetric analysis (TGA). The prepared CS-MHAP presents a significant improvement on the removal efficiency of Ni2+ ions and reactive blue 19 dye (RB19) in comparison with chitosan and magnetic hydroxyapatite nanoparticles. Moreover, the adsorption capacities were affected by several parameters such as contact time, initial concentration, adsorbent dosage, and initial pH. Interestingly, the prepared adsorbent could be easily recycled from an aqueous solution by an external magnet and reused for adsorption with high removal efficiency. PMID:24592158

Synthesis, characterisation of polyaniline-Fe3O4 magnetic nanocomposite and its application for removal of an acid violet 19 dye

NASA Astrophysics Data System (ADS)

Patil, Manohar R.; Khairnar, Subhash D.; Shrivastava, V. S.

2016-04-01

The present work deals with the development of a new method for the removal of dyes from an aqueous solution using polyaniline (PANI)-Fe3O4 magnetic nanocomposite. It is synthesised in situ through self-polymerisation of monomer aniline. Photocatalytic degradation studies were carried out for cationic acid violet 19 (acid fuchsine) dye using PANI-Fe3O4 nanocomposite in aqueous solution. Different parameters like catalyst dose, contact time and pH have been studied to optimise reaction condition. The optimum conditions for the removal of the dye are initial concentration 20 mg/l, adsorbent dose 6 gm/l, pH 7. The EDS technique gives elemental composition of synthesised PANI-Fe3O4. The SEM and XRD studies were carried for morphological feature characteristics of PANI-Fe3O4 nanocomposite. The VSM (vibrating sample magnetometer) gives magnetic property of PANI-Fe3O4 nanocomposite; also FT-IR analysis gives characteristics frequency of synthesised PANI-Fe3O4. Besides the above studies kinetic study has also been carried out.

Photodegradation mechanism and rate improvement of chlorinated aromatic dye in non-ionic surfactant solutions.

PubMed

Ma, C W; Chu, W

2001-07-01

A typical insoluble chlorinated aromatic dye (CAD), disperse red (DR), was used to explore the reaction mechanism and kinetics of photodegradation in non-ionic surfactant solutions. The use of an additional hydrogen source and photosensitizer is also studied to improve the decay rates. The decay rate of dye in surfactants depends on the Km of surfactants and their ability to offering an effective hydrogen source. The photodegradation of CAD can be divided into three stages: the initial lag stage. the fast degradation stage and the final retardation stage. The lag stage will vanish and the decay rates of dye can be greatly improved by 2.5-3.6 times after adding an additional hydrogen source (NaBH4) or photosensitizer (acetone) to the surfactant micellar solution. However, the use of an additional hydrogen source or photosensitizer has dosage limitations in such applications. The photoreduction of DR is the main reaction mechanism, in which photodechlorination is observed first with the generation of HCI as the final product, then followed by photodecolorization by breaking the azo bond of the chromophore.

Fabrication of the novel hydrogel based on waste corn stalk for removal of methylene blue dye from aqueous solution

NASA Astrophysics Data System (ADS)

Ma, Dongzhuo; Zhu, Baodong; Cao, Bo; Wang, Jian; Zhang, Jianwei

2017-11-01

The novel hydrogel based on waste corn stalk was synthetized by aqueous solution polymerization technique with functional monomers in the presence of organic montmorillonite (OMMT) under ultrasonic. In this study, batch adsorption experiments were carried out to research the effect of initial dye concentration, the dosage of hydrogel, stirring speed, contact time and temperature on the adsorption of methylene blue (MB) dye. The adsorption process was best described by the pseudo-second-order kinetic model, which confirmed that it should be a chemical process. Furthermore, we ascertained the rate controlling step by establishing the intraparticle diffusion model and the liquid film diffusion model. The adsorption and synthesis mechanisms were vividly depicted in our work as well. Structural and morphological characterizations by virtue of FTIR, FESEM, and Biomicroscope supported the relationship between the adsorption performance and material's microstructure. This research is a valuable contribution for the environmental protection, which not only converts waste corn stalks into functional materials, but improves the removal of organic dye from sewage water.

Analysis of a gas-liquid film plasma reactor for organic compound oxidation.

PubMed

Hsieh, Kevin; Wang, Huijuan; Locke, Bruce R

2016-11-05

A pulsed electrical discharge plasma formed in a tubular reactor with flowing argon carrier gas and a liquid water film was analyzed using methylene blue as a liquid phase hydroxyl radical scavenger and simultaneous measurements of hydrogen peroxide formation. The effects of liquid flow rate, liquid conductivity, concentration of dye, and the addition of ferrous ion on dye decoloration and degradation were determined. Higher liquid flow rates and concentrations of dye resulted in less decoloration percentages and hydrogen peroxide formation due to initial liquid conductivity effects and lower residence times in the reactor. The highest decoloration energy yield of dye found in these studies was 5.2g/kWh when using the higher liquid flow rate and adding the catalyst. The non-homogeneous nature of the plasma discharge favors the production of hydrogen peroxide in the plasma-liquid interface over the chemical oxidation of the organic in the bulk liquid phase and post-plasma reactions with the Fenton catalyst lead to complete utilization of the plasma-formed hydrogen peroxide. Copyright © 2016 Elsevier B.V. All rights reserved.

Removal of acid blue 062 on aqueous solution using calcinated colemanite ore waste.

PubMed

Atar, Necip; Olgun, Asim

2007-07-19

Colemanite ore waste (CW) has been employed as adsorbent for the removal of acid blue 062 anionic dye (AB 062) from aqueous solution. The adsorption of AB 062 onto CW was examined with respect to contact time, calcination temperature, particle size, pH, adsorbent dosage and temperature. The physical and chemical properties of the CW, such as particle sizes and calcinations temperature, play important roles in dye adsorption. The dye adsorption largely depends on the initial pH of the solution with maximum uptake occurring at pH 1. Three simplified kinetics models, namely, pseudo-first order, pseudo-second order, and intraparticle diffusion models were tested to investigate the adsorption mechanisms. The kinetic adsorption of AB 062 on CW follows a pseudo-second order equation. The adsorption data have been analyzed using Langmuir and Freundlich isotherms. The results indicate that the Langmuir model provides the best correlation of the experimental data. Isotherms have also been used to obtain the thermodynamic parameters such as free energy, enthalpy and entropy of the adsorption of dye onto CW.

Peroxide-assisted microwave activation of pyrolysis char for adsorption of dyes from wastewater.

PubMed

Nair, Vaishakh; Vinu, R

2016-09-01

In this study, mesoporous activated biochar with high surface area and controlled pore size was prepared from char obtained as a by-product of pyrolysis of Prosopis juliflora biomass. The activation was carried out by a simple process that involved H2O2 treatment followed by microwave pyrolysis. H2O2 impregnation time and microwave power were optimized to obtain biochar with high specific surface area and high adsorption capacity for commercial dyes such as Remazol Brilliant Blue and Methylene Blue. Adsorption parameters such as initial pH of the dye solution and adsorbent dosage were also optimized. Pore size distribution, surface morphology and elemental composition of activated biochar were thoroughly characterized. H2O2 impregnation time of 24h and microwave power of 600W produced nanostructured biochar with narrow and deep pores of 357m(2)g(-1) specific surface area. Langmuir and Langmuir-Freundlich isotherms described the adsorption equilibrium, while pseudo second order model described the kinetics of adsorption. Copyright © 2016 Elsevier Ltd. All rights reserved.

Halloysite nanotubule clay for efficient water purification.

PubMed

Zhao, Yafei; Abdullayev, Elshad; Vasiliev, Alexandre; Lvov, Yuri

2013-09-15

Halloysite clay has chemical structure similar to kaolinite but it is rolled in tubes with diameter of 50 nm and length of ca. 1000 nm. Halloysite exhibits higher adsorption capacity for both cationic and anionic dyes because it has negative SiO2 outermost and positive Al2O3 inner lumen surface; therefore, these clay nanotubes have efficient bivalent adsorbancy. An adsorption study using cationic Rhodamine 6G and anionic Chrome azurol S has shown approximately two times better dye removal for halloysite as compared to kaolin. Halloysite filters have been effectively regenerated up to 50 times by burning the adsorbed dyes. Overall removal efficiency of anionic Chrome azurol S exceeded 99.9% for 5th regeneration cycle of halloysite. Chrome azurol S adsorption capacity decreases with the increase of ionic strength, temperature and pH. For cationic Rhodamine 6G, higher ionic strength, temperature and initial solution concentration were favorable to enhanced adsorption with optimal pH 8. The equilibrium adsorption data were described by Langmuir and Freundlich isotherms. Copyright © 2013 Elsevier Inc. All rights reserved.

Comparison of Moringa stenopetala seed extract as a clean coagulant with Alum and Moringa stenopetala-Alum hybrid coagulant to remove direct dye from Textile Wastewater.

PubMed

Dalvand, Arash; Gholibegloo, Elham; Ganjali, Mohammad Reza; Golchinpoor, Najmeh; Khazaei, Mohammad; Kamani, Hossein; Hosseini, Sara Sadat; Mahvi, Amir Hossein

2016-08-01

In this study, the efficiency of Moringa stenopetala seed extract was compared with alum and M. stenopetala-alum hybrid coagulant to remove Direct Red 23 azo dye from textile wastewater. The effects of parameters such as pH, coagulant dose, type of salt used for the extraction of coagulant and initial dye concentration on dye removal efficiency were investigated. Moreover, the existing functional groups on the structure of M. stenopetala coagulant (MSC) were determined by Fourier transform infrared spectroscopy, and the morphology of sludge produced by MSC, alum, and hybrid coagulant was characterized by scanning electron microscopy. Ninhydrin test was also used to determine the quantity of primary amines in the MSC and Moringa oleifera coagulant (MOC). According to the results, with increasing the coagulant dose and decreasing the initial dye concentration, dye removal efficiency has increased. The maximum dye removal of 98.5, 98.2, and 98.3 % were obtained by using 240, 120, and 80 mg/L MSC, alum and hybrid coagulant at pH 7, respectively. The results also showed MSC was much more effective than MOC for dye removal. The volume of sludge produced by MSC was one fourth and half of those produced by alum and hybrid coagulant, respectively. Based on the results, hybrid coagulant was the most efficient coagulant for direct dye removal from colored wastewater.

Batch and column studies on biosorption of acid dyes on fresh water macro alga Azolla filiculoides.

PubMed

Padmesh, T V N; Vijayaraghavan, K; Sekaran, G; Velan, M

2005-10-17

The biosorption of Acid red 88 (AR88), Acid green 3 (AG3) and Acid orange 7 (AO7) by deactivated fresh water macro alga Azolla filiculoides was investigated in batch mode. Langmuir and Freundlich adsorption models were used for the mathematical description of the batch biosorption equilibrium data and model constants were evaluated. The adsorption capacity was pH dependent with a maximum value of 109.0 mg/g at pH 7 for AR88, 133.5 mg/g at pH 3 for AG3 and 109.6 mg/g at pH 3 for AO7, respectively, was obtained. The pseudo first and second order kinetic models were also applied to the experimental kinetic data and high correlation coefficients favor pseudo second order model for the present systems. The ability of A. filiculoides to biosorb AG3 in packed column was also investigated. The column experiments were conducted to study the effect of important design parameters such as initial dye concentration (50-100 mg/L), bed height (15-25 cm) and flow rate (5-15 mL/min) to the well-adsorbed dye. At optimum bed height (25 cm), flow rate (5 mL/min) and initial dye concentration (100 mg/L), A. filiculoides exhibited 28.1mg/g for AG3. The Bed Depth Service Time model and the Thomas model were used to analyze the experimental data and the model parameters were evaluated.

Removal of Direct Red 23 from aqueous solution using corn stalks: Isotherms, kinetics and thermodynamic studies

NASA Astrophysics Data System (ADS)

Fathi, M. R.; Asfaram, A.; Farhangi, A.

2015-01-01

The objective of this study was to assess the suitability and efficiency of corn stalk (CS) for the removal of diazo dye Direct Red 23 (DR23) from aqueous solutions. The effect of different variables in the batch method as a function of solution pH, contact time, initial dye concentration, CS amount, temperature, and so forth by the optimization method has been investigated. The color reduction was monitored by spectrophotometry at 503 nm before and after DR23 adsorption on the CS, and the removal percentage was calculated using the difference in absorbance. The sorption processes followed the pseudo second order in addition to intraparticle diffusion kinetics models with a good correlation coefficient with the overall entire adsorption of DR23 on adsorbent. The experimental equilibrium data were tested by four widely used isotherm models namely, Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich (D-R). It was found that adsorption of DR23 on CS well with the Freindlich isotherm model, implying monolayer coverage of dye molecules onto the surface of the adsorbent. More than 99% removal efficiency was obtained within 10 min at adsorbent dose of 0.2 g for initial dye concentration of 10-90 mg L-1 at pH 3. Various thermodynamic parameters, such as Gibbs free energy, entropy, and enthalpy, of the ongoing adsorption process have been calculated. Judgment based on the obtained results of thermodynamic values shows the spontaneous and endothermic nature adsorption processes on adsorbent.

Process for separating and recovering an anionic dye from an aqueous solution

DOEpatents

Rogers, R.; Horwitz, E.P.; Bond, A.H.

1998-01-13

A solid/liquid phase process for the separation and recovery of an anionic dye from an aqueous solution is disclosed. The solid phase comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the anionic dye molecules are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt. After contact between the aqueous solution and separation particles, the anionic dye is bound to the particles. The bound anionic dye molecules are freed from the separation particles by contacting the anionic dye-bound particles with an aqueous solution that does not contain a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt to form an aqueous anionic dye solution whose anionic dye concentration is preferably higher than that of the initial dye-containing solution. 7 figs.

Ultrasonic dyeing of cellulose nanofibers.

PubMed

Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

2016-07-01

Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing. Copyright © 2016 Elsevier B.V. All rights reserved.

Biosorption studies on waste cotton seed for cationic dyes sequestration: equilibrium and thermodynamics

NASA Astrophysics Data System (ADS)

Sivarajasekar, N.; Baskar, R.; Ragu, T.; Sarika, K.; Preethi, N.; Radhika, T.

2017-07-01

The immature Gossypium hirsutum seeds—an agricultural waste was converted into a novel adsorbent and its effectiveness for cationic dyes removal was discussed in this study. Characterization revealed that sulfuric acid activated waste Gossypium hirsutum seed (WGSAB) contains surface area 496 m2 g-1. The ability of WGSAB to adsorb basic red 2 (BR2) and basic violet 3 (BV3) from aqueous solutions has been studied. Batch adsorption studies were carried out at different initial dye concentrations (100-300 mg l-1), contact time (1-5 h), pH (2-12) and temperature (293-323 K) to understand the adsorption mechanism. Adsorption data were modeled using Langmuir, Freundlich and Toth adsorption isotherms. Equilibrium data of the adsorption process fitted very well to the Toth model for both dyes. The Langmuir maximum adsorption capacity was 66.69 mg g-1 for BV3 and 50.11 mg g-1 for BR2 at optimum conditions. The near unity value of Toth isotherm constant (BR2: 0.999 and BV3: 1.0) indicates that WGSAB surface is heterogeneous in nature. The maximum adsorption capacity predicted by Toth isotherm of BV3 (66.699 mg g-1) is higher than BR2 (50.310 mg g-1). The kinetic investigation revealed that the BR2 and BV3 were chemisorbed on WGSAB surface following Avrami fractional order kinetics. Further, the fractional order and rate constant values are almost similar for every concentration in both the dyes. The thermodynamic parameters such as Δ H 0, Δ S 0 and Δ G 0 were evaluated. The dye adsorption process was found to be spontaneous and endothermic for the two dyes. Regeneration of WGSAB exhausted by the two dyes could be possible via acetic acid as elutant.

Artificial neural network-genetic algorithm based optimization for the adsorption of methylene blue and brilliant green from aqueous solution by graphite oxide nanoparticle.

PubMed

Ghaedi, M; Zeinali, N; Ghaedi, A M; Teimuori, M; Tashkhourian, J

2014-05-05

In this study, graphite oxide (GO) nano according to Hummers method was synthesized and subsequently was used for the removal of methylene blue (MB) and brilliant green (BG). The detail information about the structure and physicochemical properties of GO are investigated by different techniques such as XRD and FTIR analysis. The influence of solution pH, initial dye concentration, contact time and adsorbent dosage was examined in batch mode and optimum conditions was set as pH=7.0, 2 mg of GO and 10 min contact time. Employment of equilibrium isotherm models for description of adsorption capacities of GO explore the good efficiency of Langmuir model for the best presentation of experimental data with maximum adsorption capacity of 476.19 and 416.67 for MB and BG dyes in single solution. The analysis of adsorption rate at various stirring times shows that both dyes adsorption followed a pseudo second-order kinetic model with cooperation with interparticle diffusion model. Subsequently, the adsorption data as new combination of artificial neural network was modeled to evaluate and obtain the real conditions for fast and efficient removal of dyes. A three-layer artificial neural network (ANN) model is applicable for accurate prediction of dyes removal percentage from aqueous solution by GO following conduction of 336 experimental data. The network was trained using the obtained experimental data at optimum pH with different GO amount (0.002-0.008 g) and 5-40 mg/L of both dyes over contact time of 0.5-30 min. The ANN model was able to predict the removal efficiency with Levenberg-Marquardt algorithm (LMA), a linear transfer function (purelin) at output layer and a tangent sigmoid transfer function (tansig) at hidden layer with 10 and 11 neurons for MB and BG dyes, respectively. The minimum mean squared error (MSE) of 0.0012 and coefficient of determination (R(2)) of 0.982 were found for prediction and modeling of MB removal, while the respective value for BG was the MSE and R(2) of 0.001 and 0.981, respectively. The ANN model results show good agreement with experimental data. Copyright © 2013 Elsevier B.V. All rights reserved.

Biosorption of Congo Red from aqueous solution onto burned root of Eichhornia crassipes biomass

NASA Astrophysics Data System (ADS)

Roy, Tapas Kumar; Mondal, Naba Kumar

2017-07-01

Biosorption is becoming a promising alternative to replace or supplement the present dye removal processes from dye containing waste water. In this work, adsorption of Congo Red (CR) from aqueous solution on burned root of Eichhornia crassipes ( BREC) biomass was investigated. A series of batch experiments were performed utilizing BREC biomass to remove CR dye from aqueous systems. Under optimized batch conditions, the BREC could remove up to 94.35 % of CR from waste water. The effects of operating parameters such as initial concentration, pH, adsorbent dose and contact time on the adsorption of CR were analyzed using response surface methodology. The proposed quadratic model for central composite design fitted very well to the experimental data. Response surface plots were used to determine the interaction effects of main factors and optimum conditions of the process. The optimum adsorption conditions were found to be initial CR concentration = 5 mg/L-1, pH = 7, adsorbent dose = 0.125 g and contact time = 45 min. The experimental isotherms data were analyzed using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherm equations and the results indicated that the Freundlich isotherm showed a better fit for CR adsorption. Thermodynamic parameters were calculated from Van't Hoff plot, confirming that the adsorption process was spontaneous and exothermic. The high CR adsorptive removal ability and regeneration efficiency of this adsorbent suggest its applicability in industrial/household systems and data generated would help in further upscaling of the adsorption process.

Biosorption of synthetic dyes (Direct Red 89 and Reactive Green 12) as an ecological refining step in textile effluent treatment.

PubMed

Guendouz, Samira; Khellaf, Nabila; Zerdaoui, Mostefa; Ouchefoun, Moussa

2013-06-01

With the use of cost-effective natural materials, biosorption is considered as an ecological tool that is applied worldwide for the remediation of pollution. In this study, we proposed Lemna gibba biomass (LGB), a lignocellulosic sorbent material, for the removal of two textile dyes, Direct Red 89 (DR-89) and Reactive Green 12 (RG-12). These azo dyes commonly used in dying operations of natural and synthetic fibres are the most important pollutants produced in textile industry effluents. For this purpose, batch biosorption experiments were carried out to assess the efficacy of LGB on dye treatment by evaluating the effect of contact time, biomass dosage, and initial dye concentration. The results indicated that the bioremoval efficiency of 5 mg L(-1) DR-89 and RG-12 reached approximately 100 % after 20 min of the exposure time; however, the maximum biosorption of 50 mg L(-1) DR-89 and 15 mg L(-1) RG-12 was determined to be about 60 and 47 %, respectively. Fourier transform infrared spectroscopy used to explain the sorption mechanism showed that the functional groups of carboxylic acid and hydroxyl played a major role in the retention of these pollutants on the biomass surface. The modelling results using Freundlich, Langmuir, Temkin, Elovich, and Dubini Radushkevich (D-R) isotherms demonstrated that the DR-89 biosorption process was better described with the Langmuir theory (R (2) =0.992) while the RG-12 biosorption process fitted well by the D-R isotherm equation (R (2) =0.988). The maximum biosorption capacity was found to be 20.0 and 115.5 mg g(-1) for DR-89 and RG-12, respectively, showing a higher ability of duckweed biomass for the bioremoval of the green dye. The thermodynamic study showed that the dye biosorption was a spontaneous and endothermic process. The efficacy of using duckweed biomass for the bioremoval of the two dyes was limited to concentrations ≤50 mg L(-1), indicating that L. gibba biomass may be suitable in the refining step of textile effluent treatment.

Time-of-travel data for Nebraska streams, 1968 to 1977

USGS Publications Warehouse

Petri, L.R.

1984-01-01

This report documents the results of 10 time-of-travel studies, using ' dye-tracer ' methods, conducted on five streams in Nebraska during the period 1968 to 1977. Streams involved in the studies were the North Platte, North Loup, Elkhorn, and Big Blue Rivers and Salt Creek. Rhodamine WT dye in a 20 percent solution was used as the tracer for all 10 time-of-travel studies. Water samples were collected at several points below each injection site. Concentrations of dye in the samples were measured by determining fluorescence of the sample and comparing that value to fluorescence-concentration curves. Stream discharges were measured before and during each study. Results of each time-by-travel study are shown on two tables and on graph. The first table shows water discharge at injection and sampling sites, distance between sites, and time and rate of travel of the dye between sites. The second table provides descriptions of study sites, amounts of dye injected in the streams, actual sampling times, and actual concentrations of dye detected. The graphs for each time-of-travel study provide indications of changing travel rates between sampling sites, information on length of dye clouds, and times for dye passage past given points. (USGS)

Sonocatalytic degradation of malachite green oxalate by a semiconductor metal oxide nanocatalyst.

PubMed

Bhavani, R; Sivasamy, A

2016-12-01

Advanced Oxidation Process (AOP) technologies are considered to be better technique for the degradation or mineralization of many recalcitrant compounds and pollutants. In the present study heterogeneous sonocatalytic degradation of a model organic compound such as Malachite green oxalate (MGO) was carried out in the aqueous phase. Zinc oxide nanorods were prepared by precipitation method employing zinc acetates as precursors and were characterized by FT-IR, XRD, FE-SEM and EDAX analysis. Degradation of MGO in the aqueous phase was studied in detail under the sonocatalytic process. Effects of pH, dye concentration, oxidant concentration, kinetics and effect of electrolytes on dye degradation were carried out to check the efficiency of the sonocatalyst. Effect of energy input on the degradation processes was also investigated. The degradation of dye molecules were monitored by UV-visible spectrophotometer and Chemical Oxygen demand (COD). The dye molecules were readily degraded at above 90% in the pH range 5.0-7.0 under ultrasound with zinc oxide nanorods. The interference of electrolytes like NaCl, KCl, Na 2 CO 3 , NaHCO 3 and MgSO 4 on the degradation of dye molecules were also studied on the sonocatalytic degradation of MGO. From the kinetic studies it was observed that at lower initial concentration of dye molecules the degradation efficiency was above 90%. The rate of the reaction decreased on increasing the initial dye concentrations of the dye molecules. It was observed that the complete mineralization of dye molecules was achieved without the formation of toxic by-products. The reusability of the catalyst also showed the effective degradation of the dye molecules up to five cycles without loss of the catalytic activities. Copyright © 2015 Elsevier Inc. All rights reserved.

Synthesis, Characterization and Reactivity of Nanostructured Zero-Valent Iron Particles for Degradation of Azo Dyes

NASA Astrophysics Data System (ADS)

Mikhailov, Ivan; Levina, Vera; Leybo, Denis; Masov, Vsevolod; Tagirov, Marat; Kuznetsov, Denis

Nanostructured zero-valent iron (NSZVI) particles were synthesized by the method of ferric ion reduction with sodium borohydride with subsequent drying and passivation at room temperature in technical grade nitrogen. The obtained sample was characterized by means of X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and dynamic light scattering studies. The prepared NSZVI particles represent 100-200nm aggregates, which consist of 20-30nm iron nanoparticles in zero-valent oxidation state covered by thin oxide shell. The reactivity of the NSZVI sample, as the removal efficiency of refractory azo dyes, was investigated in this study. Two azo dye compounds, namely, orange G and methyl orange, are commonly detected in waste water of textile production. Experimental variables such as NSZVI dosage, initial dye concentration and solution pH were investigated. The kinetic rates of degradation of both dyes by NSZVI increased with the decrease of solution pH from 10 to 3 and with the increase of NSZVI dosage, but decreased with the increase of initial dye concentration. The removal efficiencies achieved for both orange G and methyl orange were higher than 90% after 80min of treatment.

A comparative examination of the adsorption mechanism of an anionic textile dye (RBY 3GL) onto the powdered activated carbon (PAC) using various the isotherm models and kinetics equations with linear and non-linear methods

NASA Astrophysics Data System (ADS)

Açıkyıldız, Metin; Gürses, Ahmet; Güneş, Kübra; Yalvaç, Duygu

2015-11-01

The present study was designed to compare the linear and non-linear methods used to check the compliance of the experimental data corresponding to the isotherm models (Langmuir, Freundlich, and Redlich-Peterson) and kinetics equations (pseudo-first order and pseudo-second order). In this context, adsorption experiments were carried out to remove an anionic dye, Remazol Brillant Yellow 3GL (RBY), from its aqueous solutions using a commercial activated carbon as a sorbent. The effects of contact time, initial RBY concentration, and temperature onto adsorbed amount were investigated. The amount of dye adsorbed increased with increased adsorption time and the adsorption equilibrium was attained after 240 min. The amount of dye adsorbed enhanced with increased temperature, suggesting that the adsorption process is endothermic. The experimental data was analyzed using the Langmuir, Freundlich, and Redlich-Peterson isotherm equations in order to predict adsorption isotherm. It was determined that the isotherm data were fitted to the Langmuir and Redlich-Peterson isotherms. The adsorption process was also found to follow a pseudo second-order kinetic model. According to the kinetic and isotherm data, it was found that the determination coefficients obtained from linear method were higher than those obtained from non-linear method.

Improved biodegradation of synthetic azo dye by horseradish peroxidase cross-linked on nano-composite support.

PubMed

Sun, Huaiyan; Jin, Xinyu; Long, Nengbing; Zhang, Ruifeng

2017-02-01

A ZnO nanowires/macroporous SiO 2 composite was used as support to immobilize horseradish peroxidase (HRP) by in-situ cross-linking method. Using diethylene glycol diglycidyl ether (DDE) as a long-chained cross-linker, it was adsorbed on the surface of ZnO nanowires before reaction with HRPs, the resulted composite was quite different from the traditional cross-linking enzyme aggregates (CLEAs) on both structure and catalytic performance. The immobilized HRP showed high activity in the decolorization of azo dyes. The effect of various conditions such as the loading amount of HRP, solution pH, temperature, contact time and concentration of dye were optimized on the decolorization. The decolorization percentage of Acid Blue 113 and Acid black 10 BX reached as high as 95.4% and 90.3%, respectively. The immobilized HRP gave the highest decolorization rate under dye concentration as 50mg/L and reaction time of 35min. The immobilized HRP exhibited much better resistance to temperature and pH inactivation than free HRP. The storage stability and reusability were greatly improved through the immobilization, from the decolorization of Acid blue 113 it was found that 80.4% of initial efficiency retained after incubation at 4°C for 60 days, and that 79.4% of decolorization efficiency retained after 12 cycles reuse. Copyright © 2016 Elsevier B.V. All rights reserved.

Current Protocols in Protein Science

PubMed Central

Huynh, Kathy

2015-01-01

The purification of recombinant proteins for biochemical assays and structural studies is time-consuming and presents inherent difficulties that depend on the optimization of protein stability. The use of dyes to monitor thermal denaturation of proteins with sensitive fluorescence detection enables the rapid and inexpensive determination of protein stability using real-time PCR instruments. By screening a wide range of solution conditions and additives in 96-well format, the thermal shift assay easily identifies conditions that significantly enhance the stability of recombinant proteins. The same approach can be used as a low cost, initial screen to discover new protein:ligand interactions by capitalizing on increases in protein stability that typically occur upon ligand binding. This unit presents a methodological workflow for the small-scale, high-throughout thermal denaturation of recombinant proteins in the presence of SYPRO Orange dye. PMID:25640896

SYNTHESIS AND MUTAGENICITY OF DIRECT DYES FROM 4,4'-DIAMINO-PARA-TERPHENYL AND 4,4'-DIAMINO-PARA-QUATERPHENYL

EPA Science Inventory

DBPs in drinking water can be controlled by the type of treatment and by knowing and controlling major sources of DBP toxicant precursors and toxicants that "evade" treatment processes. Efforts are being directed at one category at a time. The initial precursor categories to be c...

Effect of dye extracting solvents and sensitization time on photovoltaic performance of natural dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Hossain, Md. Khalid; Pervez, M. Firoz; Mia, M. N. H.; Mortuza, A. A.; Rahaman, M. S.; Karim, M. R.; Islam, Jahid M. M.; Ahmed, Farid; Khan, Mubarak A.

In this study, natural dye sensitizer based solar cells were successfully fabricated and photovoltaic performance was measured. Sensitizer (turmeric) sources, dye extraction process, and photoanode sensitization time of the fabricated cells were analyzed and optimized. Dry turmeric, verdant turmeric, and powder turmeric were used as dye sources. Five distinct types of solvents were used for extraction of natural dye from turmeric. Dyes were characterized by UV-Vis spectrophotometric analysis. The extracted turmeric dye was used as a sensitizer in the dye sensitized solar cell's (DSSC) photoanode assembly. Nano-crystalline TiO2 was used as a film coating semiconductor material of the photoanode. TiO2 films on ITO glass substrate were prepared by simple doctor blade technique. The influence of the different parameters VOC, JSC, power density, FF, and η% on the photovoltaic characteristics of DSSCs was analyzed. The best energy conversion performance was obtained for 2 h adsorption time of dye on TiO2 nano-porous surface with ethanol extracted dye from dry turmeric.

Degradation of dyes from aqueous solution by Fenton processes: a review.

PubMed

Nidheesh, Puthiya Veetil; Gandhimathi, Rajan; Ramesh, Srikrishnaperumal Thanga

2013-04-01

Several industries are using dyes as coloring agents. The effluents from these industries are increasingly becoming an environmental problem. The removal of dyes from aqueous solution has a great potential in the field of environmental engineering. This paper reviews the classification, characteristics, and problems of dyes in detail. Advantages and disadvantages of different methods used for dye removal are also analyzed. Among these methods, Fenton process-based advanced oxidation processes are an emerging prospect in the field of dye removal. Fenton processes have been classified and represented as "Fenton circle". This paper analyzes the recent studies on Fenton processes. The studies include analyzing different configurations of reactors used for dye removal, its efficiency, and the effects of various operating parameters such as pH, catalyst concentration, H2O2 concentration, initial dye concentration, and temperature of Fenton processes. From the present study, it can be conclude that Fenton processes are very effective and environmentally friendly methods for dye removal.

Bioremediation of coractive blue dye by using Pseudomonas spp. isolated from the textile dye wastewater

NASA Astrophysics Data System (ADS)

Sunar, N. M.; Mon, Z. K.; Rahim, N. A.; Leman, A. M.; Airish, N. A. M.; Khalid, A.; Ali, R.; Zaidi, E.; Azhar, A. T. S.

2018-04-01

Wastewater released from the textile industry contains variety substances, mainly dyes that contains a high concentration of color and organic. In this study the potential for bacterial decolorization of coractive blue dye was examined that isolated from textile wastewater. The optimum conditions were determined for pH, temperature and initial concentration of the dye. The bacteria isolated was Pseudomonas spp. The selected bacterium shows high decolorization in static condition at an optimum of pH 7.0. The Pseudomonas spp. could decolorize coractive blue dye by 70% within 24 h under static condition, with the optimum of pH 7.0. Decolorization was confirmed by using UV-VIS spectrophotometer. This present study suggests the potential of Pseudomonas spp. as an approach in sustainable bioremediation that provide an efficient method for decolorizing coractive blue dye.

Combination of photocatalytic and membrane distillation hybrid processes for reactive dyes treatment.

PubMed

Yatmaz, H Cengiz; Dizge, Nadir; Kurt, Merve Sezen

2017-11-01

In this study, the degradation of azo dye solutions (Reactive Red 180 and Reactive Orange 16) of textile industry wastewater was investigated for using innovative hybrid process of photocatalytic and membrane distillation (MD) processes. Photocatalytic oxidation was conducted with semiconductor catalysts (ZnO and TiO2) and their mixture under UVA and UVC irradiation. More effective results were obtained under UVA at the initial stages of the reactions for both dye solutions. ZnO and TiO2 catalysts have given similar efficient results, but results with ZnO were better at initial stages. For the next stage, hybrid design of MD and photocatalytic processes was performed sequentially. Initially, the photocatalytic process was conducted for at least 1 h at initial values of 100 mg/L RR-180 dye solutions and 1 g/L ZnO catalyst loading under UVA irradiation and then treated solution was run through the distillation module at different temperatures (30°C and 40°C) and flow rates (210, 425, and 665 mL/min). Three types of membranes (polypropylene, polytetrafluoroethylene, and polyvinylidene fluoride) with different pore sizes (0.45 and 0.22 μm) were used in the module. Increasing temperature on the side of treated solution and decreasing the temperature on the other side has increased the distillate efficiency.

One-step synthesized calcium phosphate-based material for the removal of alizarin S dye from aqueous solutions: isothermal, kinetics, and thermodynamics studies

NASA Astrophysics Data System (ADS)

Adeogun, Abideen Idowu; Babu, Ramesh Balakrishnan

2015-07-01

Calcium phosphate hydroxyapatite (Ca-Hap) synthesized from CaCO3 and H3PO5, it was characterized by scanning electron microscopy, Fourier transform infrared, and X-ray diffraction. The Ca-Hap was used for the removal of Alizarin Red S dye from its aqueous solution. The kinetics, equilibrium, and thermodynamic of the adsorption of the dye onto the Ca-Hap were investigated. The effects of contact time, initial dye concentration, pH as well as temperature on adsorption capacity of Ca-Hap were studied. Experimental data were analyzed using six model equations: Langmuir, Freudlinch, Redlich-Peterson, Temkin, Dubinin-Radushkevich, and Sips isotherms and it was found that the data fitted well with Sips and Dubinin-Radushkevich isotherm models. Pseudo-first-order, pseudo-second-order, Elovic, and Avrami kinetic models were used to test the experimental data in order to elucidate the kinetic adsorption process and it was found that pseudo-second-order model best fit the data. The calculated thermodynamics parameters (∆G°, ∆H° and ∆S°) indicated that the process is spontaneous and endothermic in nature.

Corncob as an effective, eco-friendly, and economic biosorbent for removing the azo dye Direct Yellow 27 from aqueous solutions.

PubMed

Berber-Villamar, Nayda Karina; Netzahuatl-Muñoz, Alma Rosa; Morales-Barrera, Liliana; Chávez-Camarillo, Griselda Ma; Flores-Ortiz, César Mateo; Cristiani-Urbina, Eliseo

2018-01-01

The corncob is an agricultural waste generated in huge quantities during corn processing. In this paper, we tested the capacity of corncob particles for water purification by removing the azo dye Direct Yellow 27 (DY27) via biosorption. The biosorption process was investigated in terms of the kinetics, equilibria, and thermodynamics. Batch biosorption studies showed that the biosorption performance has strong inverse correlations to the solution pH and the corncob particle size, and it increases quickly with increasing contact time and initial dye concentration. The pseudo-second-order kinetic model provides the best fit to the experimental data, whereas the Redlich-Peterson isotherm model is most suitable for describing the observed equilibrium biosorption. The biosorption process is exothermic, spontaneous, and physisorption in character. Fourier transform infrared (FTIR) spectroscopy and confocal scanning laser microscopy (CSLM) studies suggest that lignocellulose and proteins play key roles in the biosorption of DY27 from aqueous solutions by corncob. Furthermore, after biosorption onto the corncob, the dye can be effectively desorbed using 0.1 M NaOH solution. Therefore, the corncob can be used as a promising biosorbent to remediate DY27-contaminated water and wastewater.

Adsorption of leather dye onto activated carbon prepared from bottle gourd: equilibrium, kinetic and mechanism studies.

PubMed

Foletto, Edson Luiz; Weber, Caroline Trevisan; Paz, Diego Silva; Mazutti, Marcio Antonio; Meili, Lucas; Bassaco, Mariana Moro; Collazzo, Gabriela Carvalho

2013-01-01

Activated carbon prepared from bottle gourd has been used as adsorbent for removal of leather dye (Direct Black 38) from aqueous solution. The activated carbon obtained showed a mesoporous texture, with surface area of 556.16 m(2) g(-1), and a surface free of organic functional groups. The initial dye concentration, contact time and pH significantly influenced the adsorption capacity. In the acid region (pH 2.5) the adsorption of dye was more favorable. The adsorption equilibrium was attained after 60 min. Equilibrium data were analyzed by the Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. The equilibrium data were best described by the Langmuir isotherm, with maximum adsorption capacity of 94.9 mg g(-1). Adsorption kinetic data were fitted using the pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models. The adsorption kinetic was best described by the second-order kinetic equation. The adsorption process was controlled by both external mass transfer and intraparticle diffusion. Activated carbon prepared from bottle gourd was shown to be a promising material for adsorption of Direct Black 38 from aqueous solution.

Corncob as an effective, eco-friendly, and economic biosorbent for removing the azo dye Direct Yellow 27 from aqueous solutions

PubMed Central

Berber-Villamar, Nayda Karina; Netzahuatl-Muñoz, Alma Rosa; Morales-Barrera, Liliana; Chávez-Camarillo, Griselda Ma.; Flores-Ortiz, César Mateo

2018-01-01

The corncob is an agricultural waste generated in huge quantities during corn processing. In this paper, we tested the capacity of corncob particles for water purification by removing the azo dye Direct Yellow 27 (DY27) via biosorption. The biosorption process was investigated in terms of the kinetics, equilibria, and thermodynamics. Batch biosorption studies showed that the biosorption performance has strong inverse correlations to the solution pH and the corncob particle size, and it increases quickly with increasing contact time and initial dye concentration. The pseudo-second-order kinetic model provides the best fit to the experimental data, whereas the Redlich-Peterson isotherm model is most suitable for describing the observed equilibrium biosorption. The biosorption process is exothermic, spontaneous, and physisorption in character. Fourier transform infrared (FTIR) spectroscopy and confocal scanning laser microscopy (CSLM) studies suggest that lignocellulose and proteins play key roles in the biosorption of DY27 from aqueous solutions by corncob. Furthermore, after biosorption onto the corncob, the dye can be effectively desorbed using 0.1 M NaOH solution. Therefore, the corncob can be used as a promising biosorbent to remediate DY27-contaminated water and wastewater. PMID:29698442

Composition and method of preparation of solid state dye laser rods

DOEpatents

Hermes, Robert E.

1992-01-01

The present invention includes solid polymeric-host laser rods prepared using bulk polymerization of acrylic acid ester comonomers which, when admixed with dye(s) capable of supporting laser oscillation and polymerized with a free radical initiator under mild thermal conditions, produce a solid product having the preferred properties for efficient lasing. Unsaturated polymerizable laser dyes can also be employed as one of the comonomers. Additionally, a method is disclosed which alleviates induced optical stress without having to anneal the polymers at elevated temperatures (>85.degree. C.).

Biosorption of alpacide blue from aqueous solution by lignocellulosic biomass: Luffa cylindrica fibers.

PubMed

Kesraoui, Aida; Moussa, Asma; Ali, Ghada Ben; Seffen, Mongi

2016-08-01

The aim of the present work is to develop an effective and inexpensive pollutant-removal technology using lignocellulosic fibers: Luffa cylindrica, for the biosorption of an anionic dye: alpacide blue. The influence of some experimental parameters such as pH, temperature, initial concentration of the polluted solution, and mass of the sorbent L. cylindrica on the biosorption of alpacide blue by L. cylindrica fibers has been investigated. Optimal parameters for maximum quantity of biosorption dye were achieved after 2 h of treatment in a batch system using an initial dye concentration of 20 mg/L, a mass of 1 g of L. cylindrica fibers, and pH 2. In these conditions, the quantity of dye retained is 2 mg/g and the retention rate is 78 %. Finally, a mathematical modeling of kinetics and isotherms has been used for mathematical modeling; the model of pseudo-second order is more appropriate to describe this phenomenon of biosorption. Concerning biosorption isotherms, the Freundlich model is the most appropriate for a biosorption of alpacide blue dye by L. cylindrica fibers.

Decolorization and Detoxification of Textile Dyes with a Laccase from Trametes hirsuta

PubMed Central

Abadulla, Elias; Tzanov, Tzanko; Costa, Silgia; Robra, Karl-Heinz; Cavaco-Paulo, Artur; Gübitz, Georg M.

2000-01-01

Trametes hirsuta and a purified laccase from this organism were able to degrade triarylmethane, indigoid, azo, and anthraquinonic dyes. Initial decolorization velocities depended on the substituents on the phenolic rings of the dyes. Immobilization of the T. hirsuta laccase on alumina enhanced the thermal stabilities of the enzyme and its tolerance against some enzyme inhibitors, such as halides, copper chelators, and dyeing additives. The laccase lost 50% of its activity at 50 mM NaCl while the 50% inhibitory concentration (IC50) of the immobilized enzyme was 85 mM. Treatment of dyes with the immobilized laccase reduced their toxicities (based on the oxygen consumption rate of Pseudomonas putida) by up to 80% (anthraquinonic dyes). Textile effluents decolorized with T. hirsuta or the laccase were used for dyeing. Metabolites and/or enzyme protein strongly interacted with the dyeing process indicated by lower staining levels (K/S) values than obtained with a blank using water. However, when the effluents were decolorized with immobilized laccase, they could be used for dyeing and acceptable color differences (ΔE*) below 1.1 were measured for most dyes. PMID:10919791

On the possibility of measuring atmospheric OH using intracavity laser spectroscopy

NASA Technical Reports Server (NTRS)

Mcmanus, J. Barry; Kolb, C. E.

1994-01-01

Intracavity laser spectroscopy (ILS) has been demonstrated to be useful for measuring extremely weak absorption produced by gases in air. ILS is based on the observation that when there are spectrally narrow losses within the cavity of a broadband laser, the laser output has corresponding spectral holes where the laser oscillation is partially quenched. The depth of the laser output dips can be enhanced by a factor of 10(exp 5) over the depth of the initial cavity loss, and absorptivities of 10(exp -8) cm(exp -1) have been measured in lasers only one meter long. With ILS, one can achieve in a compact space a spectral contrast that would otherwise require kilometers of pathlength. ILS systems typically use quasi-continuous wave dye lasers operating close to threshold. The pump laser is modulated from just below to just above the threshold level for the dye laser, and the dye laser output is spectroscopically observed during a well defined time interval after the onset of lasing (the generation time). The spectral contrast of an intracavity absorber is equivalent to that produced by absorption through a path length equal to the generation time multiplied by the speed of light (assuming the cavity is completely filed with the absorber) up to some limiting time. Thus, if one measures the spectrum after 33 microseconds, the effective path length is 10,000 meters.

Determination of traveltimes in the lower San Joaquin River basin, California, from dye-tracer studies during 1994-1995

USGS Publications Warehouse

Kratzer, Charles R.; Biagtan, Rhoda N.

1997-01-01

Dye-tracer studies were done in the lower San Joaquin River Basin in February 1994, June 1994, and February 1995. Dye releases were made in the Merced River (February 1994), Salt Slough (June 1994), Tuolumne River (February 1995), and Dry Creek (February 1995). The traveltimes determined in the studies aided the interpretation of pesticide data collected during storm sampling and guided sample collection during a Lagrangian pesticide study. All three studies used rhodamine WT 20-percent dye solution, which was released as a slug in midstream. The mean traveltime determined in the dye studies were compared to estimates based on regression equations of mean stream velocity as a function of streamflow. Dye recovery, the ratio of the calculated dye load at downstream sites to the initial amount of dye released, was determined for the 1994 studies and a dye-dosage formula was evaluated for all studies. In the February 1994 study, mean traveltime from the Merced River at River Road to the San Joaquin River near Vernalis (46.8 river miles) was 38.5 hours, and to the Delta-Mendota Canal at Tracy pumps (84.3 river miles) was 90.4 hours. In the June 1994 study, mean traveltime from Salt Slough at Highway 165 to Vernalis (64.0 river miles) was 80.1 hours. In the February 1995 study, the mean traveltime from the Tuolumne River at Roberts Ferry to Vernalis (51.5 river miles) was 35.8 hours. For the 1994 studies, the regression equations provided suitable estimates of travel-time, with ratios of estimated traveltime to mean dye traveltime of 0.94 to 1.08. However, for the 1995 dye studies, the equations considerably underestimated traveltime, with ratios of 0.49 to 0.73.In the February 1994 study, 70 percent of the dye released was recovered at Vernalis and 35percent was recovered at the Delta-Mendota Canal at Tracy pumps. In the June 1994 study, recovery was 61 percent at Patterson, 43 percent just upstream of the Tuolumne River confluence, and 37 percent at Vernalis. The dye-dosage formula overestimated the dye required for a given downstream concentration for the 1994 studies by ratios of 1.07 to 2.12. The ratios for the February 1995 studies were 0.67 to 0.95 for the Tuolumne River and 1.21 for Dry Creek. In all studies, the estimates improved with length of dye study.

Structure and reactivity of thiazolium azo dyes: UV-visible, resonance Raman, NMR, and computational studies of the reaction mechanism in alkaline solution.

PubMed

Abbott, Laurence C; Batchelor, Stephen N; Moore, John N

2013-03-07

UV-visible absorption, resonance Raman, and (1)H NMR spectroscopy, allied with density functional theory (DFT) calculations, have been used to study the structure, bonding, and alkaline hydrolysis mechanism of the cationic thiazloium azo dye, 2-[2-[4-(diethylamino)phenyl]diazenyl]-3-methyl-thiazolium (1a), along with a series of six related dyes with different 4-dialkylamino groups and/or other phenyl ring substituents (2a-c, 3a-c) and the related isothiazolium azo dye, 5-[2-[4-(dimethylamino)phenyl]diazenyl]-2-methyl-isothiazolium (4). These diazahemicyanine dyes are calculated to have a similar low-energy structure that is cis, trans at the (iso)thiazolium-azo group, and for which the calculated Raman spectra provide a good match with the experimental data; the calculations on these structures are used to assign and discuss the transitions giving rise to the experimental spectra, and to consider the bonding and its variation between the dyes. UV-visible, Raman, and NMR spectra recorded from minutes to several weeks after raising the pH of an aqueous solution of 1a to ca. 11.5 show that the dominant initial step in the reaction is loss of diethylamine to produce a quinonimine (ca. hours), with subsequent reactions occurring on longer time scales (ca. days to weeks); kinetic analyses give a rate constant of 2.6 × 10(-2) dm(3) mol(-1) s(-1) for reaction of 1a with OH(-). UV-visible spectra recorded on raising the pH of the other dyes in solution show similar changes that are attributed to the same general reaction mechanism, but with different rate constants for which the dependence on structure is discussed.

Enhanced visible photocatalytic activity of cotton ball like nano structured Cu doped ZnO for the degradation of organic pollutant.

PubMed

Thennarasu, G; Sivasamy, A

2016-12-01

Stringent Environmental standards followed worldwide led to the emergence of advanced oxidation process for the removal of toxic contaminants from water and wastewater. Among all semiconductor photocatalysts have great potential in the degradation of organic and inorganic pollutants into lesser harmful products under visible light irradiations. The present research work describes the synthesis of Cu doped ZnO (CuDZ) via a co-precipitation method to attain high crystallized powder confirmed by XRD analysis. The FE-SEM images showed that the CuDZ has cotton ball like morphology with a uniform size ranged from 25 to 40nm. TEM, FT-IR and UV-DRS studies of the synthesized CuDZ are also discussed in detail. The photocatalytic activity of the as prepared CuDZ catalyst was tested for the degradation of Direct Blue 71 (DB 71) dye in aqueous phase under visible light irradiation. The degree of degradation was found to be dependent on aqueous phase pH, duration of irradiation time, amount of photocatalyst, the initial dye concentration and kinetics of photodegradation. The maximum photocatytic degradation of DB 71 dye was found to be effective at pH 6.8. The optimum amount of photocatalyst was found 3gL -1 of CuDZ for the complete degradation of DB 71 dye (0.01gL -1 ). The reusability of the photocatalyst indicates that 96% of DB 71 dye was degraded up to 3rd cycles of use. The visible photodegradation of DB 71 dye was exhibited pseudo-first-order kinetics. Chemical oxygen demand and ESI-MS studies confirmed the complete mineralization of DB 71 dye molecules. Copyright © 2015 Elsevier Inc. All rights reserved.

Adsorption studies of methylene blue and gentian violet on sugarcane bagasse modified with EDTA dianhydride (EDTAD) in aqueous solutions: kinetic and equilibrium aspects.

PubMed

Gusmão, Karla Aparecida Guimarães; Gurgel, Leandro Vinícius Alves; Melo, Tânia Márcia Sacramento; Gil, Laurent Frédéric

2013-03-30

In this study the adsorption of cationic dyes by modified sugarcane bagasse with EDTA dianhydride (EB) was examined using methylene blue (MB) and gentian violet (GV) as model compounds in aqueous single solutions. The synthesized adsorbent (EB) was characterized by FTIR, elemental analysis, and BET. The capacity of EB to adsorb dyes was evaluated at different contact times, pH values, and initial dye concentrations. According to the obtained results, the adsorption processes could be described by a pseudo-second-order kinetic model. The adsorption isotherms were well fitted by the Langmuir model. Maximum adsorption capacities for MB and GV on EB were found to be 202.43 and 327.83 mg/g, respectively. The free energy change during adsorption of MB and GV was found to be -22.50 and -24.21 kJ/mol, respectively, suggesting that chemisorption is the main mechanism controlling the adsorption process. Copyright © 2013 Elsevier Ltd. All rights reserved.

Jute stick powder as a potential biomass for the removal of congo red and rhodamine B from their aqueous solution.

PubMed

Panda, Gopal C; Das, Sujoy K; Guha, Arun K

2009-05-15

Jute stick powder (JSP) has been found to be a promising material for adsorptive removal of congo red (C.I. 22120) and rhodamine B (C.I. 45170) from aqueous solutions. Physico-chemical parameters like dye concentration, solution pH, temperature and contact time have been varied to study the adsorption phenomenon. Favorable adsorption occurs at around pH 7.0 whereas temperature has no significant effect on adsorption of both the dyes. The maximum adsorption capacity has been calculated to be 35.7 and 87.7mg/g of the biomass for congo red and rhodamine B, respectively. The adsorption process is in conformity with Freundlich and Langmuir isotherms for rhodamine B whereas congo red adsorption fits well to Langmuir isotherm only. In both the cases, adsorption occurs very fast initially and attains equilibrium within 60min. Kinetic results suggest the intra-particle diffusion of dyes as rate limiting step.

Separation of acid blue 25 from aqueous solution using water lettuce and agro-wastes by batch adsorption studies

NASA Astrophysics Data System (ADS)

Kooh, Muhammad Raziq Rahimi; Dahri, Muhammad Khairud; Lim, Linda B. L.; Lim, Lee Hoon; Chan, Chin Mei

2018-05-01

Three plant-based materials, namely water lettuce (WL), tarap peel (TP) and cempedak peel (CP), were used to investigate their potentials as adsorbents using acid blue 25 (AB25) dye as a model for acidic dye. The adsorbents were characterised using Fourier transform infrared spectroscopy, X-ray fluorescence and scanning electron microscope. Batch experiments involving parameters such as pH, temperature, contact time, and initial dye concentration were done to investigate the optimal conditions for the adsorption of AB25 onto the adsorbents. Thermodynamics study showed that the uptake of AB25 by the three adsorbents was feasible and endothermic in nature. Both the Langmuir and Freundlich isotherm models can be used to describe the adsorption process of AB25 onto WL and CP while pseudo-second-order fitted the kinetics data, suggesting that chemisorptions were majorly involved. The use of 0.1 M of NaOH showed the best results in regenerating of the WL, TP and CP's adsorption ability after AB25 treatment.

Determination of fast ozone oxidation rate for textile dyes by using a continuous quench-flow system.

PubMed

Gomes, Arlindo C; Nunes, José C; Simões, Rogério M S

2010-06-15

To study the fast kinetic decolourisation of textile dyes by ozone a continuous quench-flow system was used. This system has not been used before for these purposes. Reaction times in the range of 7-3000 ms were explored. The reaction was quenched with potassium iodide, which proved to be very effective, and the indigo method was used to follow the ozone concentration. Dyes from the most representative chemical classes currently used in the textile industry, i.e. azo and anthraquinone, were selected. Using the initial slope method, the effect of dye and ozone concentrations was researched and the kinetic equations thus established. Using tert-butyl alcohol, as radical scavenger, and pH close to 2.5, the second-order rate constant of the reactant dyes at 280 K varies in the range of 1.20x10(4)-7.09x10(5)M(-1)s(-1); the Acid Orange 7 exhibiting thus its lowest value, the Acid Blue 45 its highest value and the Acid Green 25 and 27 and Direct Yellow 4 intermediate values (approximately 1.6x10(5)M(-1)s(-1)). Without radical scavenger and the pH close to 4, the reaction rate increases one order of magnitude, but, on the reverse, the efficiency of ozone to decolourisation decreases. Copyright 2010 Elsevier B.V. All rights reserved.

Adsorption capacity of Curcuma longa for the removal of basic green 1 dye--equilibrium, kinetics and thermodynamic study.

PubMed

Roopavathi, K V; Shanthakumar, S

2016-09-01

In the present study, Curcuma longa (turmeric plant) was used as an adsorbent to remove Basic Green 1 (BG) dye. Batch study was carried out to evaluate the adsorption potential of C. longa and influencing factors such as pH (4-10), adsorbent dose (0.2-5 g l-1), initial dye concentration (50-250 mg l-1) and temperature (30-50°C) on dye removal were analysed. The characterisation of adsorbent was carried out using fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and Brunauer, Emmett and Teller (BET) method. Isotherm models that included Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich, and kinetic models such as pseudo first order, pseudo second-order, Elovich and intraparticle diffusion models were studied. A maximum removal percentage (82.76%) of BG dye from aqueous solution was obtained with optimum conditions of pH 7, 1g l-1 adsorbent dose and 30°C temperature, for 100 mg l-1 initial dye concentration. The equilibrium and kinetic study revealed that the experimental data fitted suitably the Freundlich isotherm and Pseudo second order kinetic model. Thermodynamic analysis proved that adsorption system in this study was spontaneous, feasible and endothermic in nature.

The potential use of activated carbon prepared from Ziziphus species for removing dyes from waste waters

NASA Astrophysics Data System (ADS)

Regti, Abdelmajid; Laamari, My Rachid; Stiriba, Salah-Eddine; El Haddad, Mohammadine

2017-11-01

In this study, the adsorption potential of activated carbon prepared from Ziziphus mauritiana nuts for the removal of methylene blue (MB) from aqueous solution has been investigated using batch mode experiments. The effects of some operating parameters on the removal dye such as, initial pH (2-12), temperature (298-328 K), initial MB concentration (20-100 mg L-1), and contact time (5-70 min) were investigated. Adsorption kinetic showed that the rate adsorption followed the pseudo-second-order kinetic model. Four adsorption isotherms models were applied to experimental equilibrium data (Langmuir, Freundlich, Redlich-Peterson, and Fritz-Schlunder) and the different constants were calculated using non-linear equations models. Fritz-Schlunder model was found the best one to describe the adsorption process which suggests that the adsorption of MB onto activated carbon derived from Ziziphus mauritiana is heterogeneous with a multilayer. Thermodynamic adsorption showed that the process was endothermic and spontaneous in nature.

Photocatalytic degradation of organic dyes by Er3+: YAlO3/Co- and Fe-doped ZnO coated composites under solar irradiation

NASA Astrophysics Data System (ADS)

Chen, Yang; Lu, Chunxiao; Tang, Liang; Song, Yahui; Wei, Shengnan; Rong, Yang; Zhang, Zhaohong; Wang, Jun

2016-12-01

In this work, the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites were prepared by the sol-gel method. Then, they were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). Photo-degradation of azo fuchsine (AF) as a model dye under solar light irradiation was studied to evaluate the photocatalytic activity of the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites. It was found that the photocatalytic activity of Co- and Fe-doped ZnO composites can be obviously enhanced by upconversion luminescence agent (Er3+: YAlO3). Besides, the photocatalytic activity of Er3+: YAlO3/Fe-doped ZnO is better than that of Er3+: YAlO3/Co-doped ZnO. The influence of experiment conditions, such as the concentration of Er3+: YAlO3, heat-treatment temperature and time on the photocatalytic activity of the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites was studied. In addition, the effects of solar light irradiation time, dye initial concentration, Er3+: YAlO3/Co- and Fe-doped ZnO amount on the photocatalytic degradation of azo fuchsine in aqueous solution were investigated in detail. Simultaneously, some other organic dyes, such as Methyl Orange (MO), Rhodamine B (RM-B), Acid Red B (AR-B), Congo Red (CR), and Methyl Blue (MB) were also studied. The possible excitation principle of Er3+: YAlO3/Co- and Fe-doped ZnO coated composites under solar light irradiation and the photocatalytic degradation mechanism of organic dyes were discussed.

Removal of reactive red-120 and 4-(2-pyridylazo) resorcinol from aqueous samples by Fe3O4 magnetic nanoparticles using ionic liquid as modifier.

PubMed

Absalan, Ghodratollah; Asadi, Mozaffar; Kamran, Sedigheh; Sheikhian, Leila; Goltz, Douglas M

2011-08-30

The nanoparticles of Fe(3)O(4) as well as the binary nanoparticles of ionic liquid and Fe(3)O(4) (IL-Fe(3)O(4)) were synthesized for removal of reactive red 120 (RR-120) and 4-(2-pyridylazo) resorcinol (PAR) as model azo dyes from aqueous solutions. The mean size and the surface morphology of the nanoparticles were characterized by TEM, DLS, XRD, FTIR and TGA techniques. Adsorption of RR-120 and PAR was studied in a batch reactor at different experimental conditions such as nanoparticle dosage, dye concentration, pH of the solution, ionic strength, and contact time. Experimental results indicated that the IL-Fe(3)O(4) nanoparticles had removed more than 98% of both dyes under the optimum operational conditions of a dosage of 60mg, a pH of 2.5, and a contact time of 2min when initial dyes concentrations of 10-200mg L(-1) were used. The maximum adsorption capacity of IL-Fe(3)O(4) was 166.67 and 49.26mg g(-1) for RR-120 and PAR, respectively. The isotherm experiments revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The Langmuir adsorption constants were 5.99 and 3.62L mg(-1) for adsorptions of RR-120 and PAR, respectively. Both adsorption processes were endothermic and dyes could be desorbed from IL-Fe(3)O(4) by using a mixed NaCl-acetone solution and adsorbent was reusable. Copyright © 2011 Elsevier B.V. All rights reserved.

Ultrasonically assisted hydrothermal synthesis of activated carbon-HKUST-1-MOF hybrid for efficient simultaneous ultrasound-assisted removal of ternary organic dyes and antibacterial investigation: Taguchi optimization.

PubMed

Azad, F Nasiri; Ghaedi, M; Dashtian, K; Hajati, S; Pezeshkpour, V

2016-07-01

Activated carbon (AC) composite with HKUST-1 metal organic framework (AC-HKUST-1 MOF) was prepared by ultrasonically assisted hydrothermal method and characterized by FTIR, SEM and XRD analysis and laterally was applied for the simultaneous ultrasound-assisted removal of crystal violet (CV), disulfine blue (DSB) and quinoline yellow (QY) dyes in their ternary solution. In addition, this material, was screened in vitro for their antibacterial actively against Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PAO1) bacteria. In dyes removal process, the effects of important variables such as initial concentration of dyes, adsorbent mass, pH and sonication time on adsorption process optimized by Taguchi approach. Optimum values of 4, 0.02 g, 4 min, 10 mg L(-1) were obtained for pH, AC-HKUST-1 MOF mass, sonication time and the concentration of each dye, respectively. At the optimized condition, the removal percentages of CV, DSB and QY were found to be 99.76%, 91.10%, and 90.75%, respectively, with desirability of 0.989. Kinetics of adsorption processes follow pseudo-second-order model. The Langmuir model as best method with high applicability for representation of experimental data, while maximum mono layer adsorption capacity for CV, DSB and QY on AC-HKUST-1 estimated to be 133.33, 129.87 and 65.37 mg g(-1) which significantly were higher than HKUST-1 as sole material with Qm to equate 59.45, 57.14 and 38.80 mg g(-1), respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Power ultrasound-assisted cleaner leather dyeing technique: influence of process parameters.

PubMed

Sivakumar, Venkatasubramanian; Rao, Paruchuri Gangadhar

2004-03-01

The application of power ultrasound to leather processing has a significant role in the concept of "clean technology" for leather production. The effect of power ultrasound in leather dyeing has been compared with dyeing in the absence of ultrasound and conventional drumming. The power ultrasound source used in these experiments was ultrasonic cleaner (150 W and 33 kHz). The effect of various process parameters such as amount of dye offer, temperature, and type of dye has been experimentally found out. The effect of presonication of dye solution as well as leather has been studied. Experiments at ultrasonic bath temperature were carried out to find out the combined thermal as well as stirring effects of ultrasound. Dyeing in the presence of ultrasound affords about 37.5 (1.8 times) difference as increase in % dye exhaustion or about 50% decrease in the time required for dyeing compared to dyeing in the absence of ultrasound for 4% acid red dye. About 29 (1.55 times) increase in % dye exhaustion or 30% reduction in time required for dyeing was observed using ultrasound at stationary condition compared with conventional dynamic drumming conditions. The effect of ultrasound at constant temperature conditions with a control experiment has also been studied. The dye exhaustion increases as the temperature increases (30-60 degrees C) and better results are observed at higher temperature due to the use of ultrasound. Presonication of dye solution or crust leather prior to the dyeing process has no significant improvement in dye exhaustion, suggesting ultrasound effect is realized when it is applied during the dyeing process. The results indicate that 1697 and 1416 ppm of dye can be reduced in the spent liquor due to the use of ultrasound for acid red (for 100 min) and acid black (for 3 h) dyes, respectively, thereby reducing the pollution load in the effluent stream. The color yield of the leather as inferred from the reflectance measurement indicates that dye offer can be halved when ultrasound is employed to promote dyeing. Scanning electron microscopy analysis of the cross section of the dyed leather indicates that fiber structure is not affected due to the use of ultrasound under the given process conditions. The present study clearly demonstrates that ultrasound can be used as a tool to improve the rate of exhaustion of dye, reduce pollution load in the spent effluent liquor, and improve the quality of leather produced. The study also offered provision to employ optimum levels of chemicals and increases percentage exhaustion for a given time, thereby limiting the pollution load in the tannery effluent, which is of great social concern.

Adsorption of crystal violet onto functionalised multi-walled carbon nanotubes: Equilibrium and kinetic studies.

PubMed

Sabna, V; Thampi, Santosh G; Chandrakaran, S

2016-12-01

Synthetic dyes present in effluent from textile, paper and paint industries contain crystal violet (CV), a known carcinogenic agent. This study investigates the modification of multiwalled carbon nanotubes by acid reflux method and equilibrium and kinetic behaviour of adsorption of CV onto functionalized multi-walled carbon nanotubes (fMWNTs) in batch system. High stability of the fMWNTs suspension in water indicates the hydrophilicity of fMWNTs induced due to the formation of functional groups that make hydrogen bonds with water molecules. fMWNTs were characterized by Fourier Transform Infra Red (FTIR) spectroscopy and the functional groups present on the fMWNTs were confirmed. Characteristic variation was observed in the FTIR spectra of fMWNTs after adsorption of crystal violet onto it. Adsorption characteristics were evaluated as a function of system variables such as contact time, dosage of fMWNTs and initial concentration and pH of the crystal violet solution. Adsorption capacity of fMWNTs and percentage removal of the dye increased with increase in contact time, adsorbent dosage and pH but declined with increase in initial concentration of the dye. fMWNTs showed higher adsorption capacity compared to that of pristine MWNTs. Data showed good fit with the Langmuir and Freundlich isotherm models and the pseudo-second order kinetic model; the maximum adsorption capacity was 90.52mg/g. Kinetic parameters such as rate constants, equilibrium adsorption capacities and regression coefficients were estimated. Results indicate that fMWNTs are an effective adsorbent for the removal of crystal violet from aqueous solution. Copyright © 2015 Elsevier Inc. All rights reserved.

Biosorption of Basic Green 4 from aqueous solution by Ananas comosus (pineapple) leaf powder.

PubMed

Chowdhury, Shamik; Chakraborty, Sagnik; Saha, Papita

2011-06-01

Biosorption characteristics of Ananas comosus (pineapple) leaf powder was investigated for decolorization of Basic Green 4 (BG 4), a cationic dye from its aqueous solutions employing a batch experimental set-up. Parameters that influence the sorption process such as pH, biosorbent dosage, contact time, initial dye concentration and temperature were systematically studied. The optimum conditions for removal of BG 4 were found to be pH 9.0, contact time=150 min, biosorbent dosage=5.0 g L(-1), initial dye concentration=50 mg L(-1). The temperature had a strong influence on the biosorption process. Further, the biosorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and Brunauer, Emmett, Teller (BET) surface area and pore size analysis. Experimental biosorption data were modeled by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. The biosorption process followed the Langmuir isotherm model with high coefficients of correlation (R(2)>0.99) at different temperatures. The pseudo second order kinetic model fitted well in correlation to the experimental results. Activation energy of the biosorption process (E(a)) was found to be 45.79 kJ mol(-1) by using the Arrhenius equation, indicating chemisorption nature of BG 4 sorption onto pineapple leaf powder. Thermodynamic parameters suggest that the biosorption process is spontaneous and exothermic in nature. Overall, the present findings suggest that this environmentally friendly, efficient and low-cost biosorbent may be useful for the removal of BG 4 from aqueous media. Copyright © 2011 Elsevier B.V. All rights reserved.

Analysis of protein stability and ligand interactions by thermal shift assay.

PubMed

Huynh, Kathy; Partch, Carrie L

2015-02-02

Purification of recombinant proteins for biochemical assays and structural studies is time-consuming and presents inherent difficulties that depend on the optimization of protein stability. The use of dyes to monitor thermal denaturation of proteins with sensitive fluorescence detection enables rapid and inexpensive determination of protein stability using real-time PCR instruments. By screening a wide range of solution conditions and additives in a 96-well format, the thermal shift assay easily identifies conditions that significantly enhance the stability of recombinant proteins. The same approach can be used as an initial low-cost screen to discover new protein-ligand interactions by capitalizing on increases in protein stability that typically occur upon ligand binding. This unit presents a methodological workflow for small-scale, high-throughput thermal denaturation of recombinant proteins in the presence of SYPRO Orange dye. Copyright © 2015 John Wiley & Sons, Inc.

Decolorisation of Basic Textile Dye from Aqueous Solutions using a Biosorbent derived from Thespesia populnea used Biomass

NASA Astrophysics Data System (ADS)

Gunturu, Bhargavi; Rao Palukuri, Nageswara; Sahadevan, Renganathan

2018-03-01

In the present study, the efficiency of a biosorbent derived from seeds of Thespesia populnea was investigated towards the removal of basic textile dye Methylene Blue from an aqueous solution. Adsorption studies were carried out in batch system. Influence of experimental parameters such as adsorbent dosage (0.1g/L-0.3g/L), PH (2-10) and initial dye concentration (50-130mg/L) on adsorption of dye onto biosorbent was investigated. Maximum uptake of dye was observed with 0.1g/L adsorbent dosage at PH 8.0. Equilibrium uptake of methylene blue dye by the adsorbent was analyzed by Langmuir and Freundlich isotherm models. The data fitted best with Freundlich model, suggesting that adsorption of the dye was by multilayer model on the surface of the adsorbent. Experimental results obtained support that the biosorbent used in the present study can be a suitable low cost alternate for the removal of basic textile dyes.

Sonochemical assisted hydrothermal synthesis of ZnO: Cr nanoparticles loaded activated carbon for simultaneous ultrasound-assisted adsorption of ternary toxic organic dye: Derivative spectrophotometric, optimization, kinetic and isotherm study.

PubMed

Jamshidi, M; Ghaedi, M; Dashtian, K; Hajati, S; Bazrafshan, A A

2016-09-01

Chromium doped zinc oxide nanoparticles (ZnO: Cr-NPs) was synthesized by ultrasonically assisted hydrothermal method and characterized by FE-SEM, XRD and TEM analysis. Subsequently, this composite ultrasonically assisted was deposited on activated carbon (ZnO: Cr-NPs-AC) and used for simultaneous ultrasound-assisted removal of three toxic organic dye namely of malachite green (MG), eosin yellow (EY) and Auramine O (AO). Dyes spectra overlap in mixture (major problem for simultaneous investigation) of this systems was extensively resolved by derivative spectrophotometric method. The magnitude of variables like initial dyes concentration, adsorbent mass and sonication time influence on dyes removal was optimized using small central composite design (CCD) combined with desirability function (DF) approach, while pH was studied by one-a-time approach. The maximized removal percentages at desirability of 0.9740 was set as follow: pH 6.0, 0.019g ZnO: Cr-NPs-AC, 3.9min sonication at 4.5, 4.8 and 4.7mgL(-1) of MG, EY and AO, respectively. Above optimized points lead to achievement of removal percentage of 98.36%, 97.24%, and 99.26% correspond to MG, EY and AO, respectively. ANOVA for each dyes based p-value less than (<0.0001) suggest highly efficiency of CCD model for prediction of data concern to simultaneous removal of these dyes within 95% confidence interval, while their F-value for MG, EY and AO is 935, 800.2, and 551.3, respectively, that confirm low participation of this them in signal. The value of multiple correlation coefficient R(2), adjusted and predicted R(2) for simultaneous removal of MG is 0.9982, 0.9972 and 0.9940, EY is 0.9979, 0.9967 and 0.9930 and for AO is 0.9970, 0.9952 and 0.9939. The adsorption rate well fitted by pseudo second-order and Langmuir model via high, economic and profitable adsorption capacity of 214.0, 189.7 and 211.6mgg(-1) for MG, EY and AO, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultrafast electron and hole transfer dynamics of a solar cell dye containing hole acceptors on mesoporous TiO2 and Al2O3.

PubMed

Scholz, Mirko; Flender, Oliver; Boschloo, Gerrit; Oum, Kawon; Lenzer, Thomas

2017-03-08

The stability of dye cations against recombination with conduction band electrons in mesoporous TiO 2 electrodes is a key property for improving light harvesting in dye-sensitised solar cells. Using ultrafast transient broadband absorption spectroscopy, we monitor efficient intramolecular hole transfer in the solar cell dye E6 having two peripheral triarylamine acceptors. After photoexcitation, two hole transfer mechanisms are identified: a concerted mechanism for electron injection and hole transfer (2.4 ps) and a sequential mechanism with time constants of 3.9 ps and 30 ps. This way the dye retards unwanted recombination with a TiO 2 conduction band electron by quickly moving the hole further away from the surface. Contact of the E6/TiO 2 surface with the solvent acetonitrile has almost no influence on the electron injection and hole transfer kinetics. Fast hole transfer (2.8 ps) is also observed on a "non-injecting" Al 2 O 3 surface generating a radical cation-radical anion species with a lifetime of 530 ps. The findings confirm the good intramolecular hole transfer properties of this dye on both thin films. In contrast, intramolecular hole transfer does not occur in the mid-polar organic solvent methyl acetate. This is confirmed by TDDFT calculations suggesting a polarity-induced reduction of the driving force for hole transfer. In methyl acetate, only the relaxation of the initially photoexcited core chromophore is observed including solvent relaxation processes of the electronically excited state S 1 /ICT.

A new morphological approach for removing acid dye from leather waste water: preparation and characterization of metal-chelated spherical particulated membranes (SPMs).

PubMed

Şenay, Raziye Hilal; Gökalp, Safiye Meriç; Türker, Evren; Feyzioğlu, Esra; Aslan, Ahmet; Akgöl, Sinan

2015-03-15

In this study, p(HEMA-GMA) poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) spherical particulated membranes (SPMs) were produced by UV-photopolymerization and the synthesized SPMs were coupled with iminodiacetic acid (IDA). Finally the novel SPMs were chelated with Cr(III) ions as ligand and used for removing acid black 210 dye. Characterizations of the metal-chelated SPMs were made by SEM, FTIR and swelling test. The water absorption capacities and acid dye adsorption properties of the SPMs were investigated and the results were 245.0, 50.0, 55.0 and 51.9% for p(HEMA), p(HEMA-GMA), p(HEMA-GMA)-IDA and p(HEMA-GMA)-IDA-Cr(III) SPMs respectively. Adsorption properties of the p(HEMA-GMA)-IDA-Cr(III) SPMs were investigated under different conditions such as different initial dye concentrations and pH. The optimum pH was observed at 4.3 and the maximum adsorption capacity was determined as 885.14 mg/g at about 8000 ppm initial dye concentration. The concentrations of the dyes were determined using a UV/Vis Spectrophotometer at a wavelength of 435 nm. Reusability of p(HEMA-GMA)-IDA-Cr(III) SPMs was also shown for five adsorption-desorption cycles without considerable decrease in its adsorption capacity. Finally, the results showed that the metal-chelated p(HEMA-GMA)-IDA SPMs were effective sorbent systems removing acid dye from leather waste water. Copyright © 2014 Elsevier Ltd. All rights reserved.

Phytoextraction potential of water fern (Azolla pinnata) in the removal of a hazardous dye, methyl violet 2B: Artificial neural network modelling.

PubMed

Kooh, Muhammad Raziq Rahimi; Lim, Linda B L; Lim, Lee-Hoon; Malik, Owais Ahmed

2018-04-16

This study investigated the potential of Azolla pinnata (AP) in the removal of toxic methyl violet 2B (MV) dye wastewater using the phytoextraction approach with the inclusion of an Artificial Neural Network (ANN) modelling. Parameters examined included the effects of dye concentration, pH and plant dosage. The highest removal efficiency was 93% which was achieved at a plant dosage of 0.8 g (dye volume = 200 mL, initial pH = 6.0, initial dye concentration = 10 mg L -1 ). A significant decrease in relative frond number (RFN), a growth rate estimator, observed at a dye concentration of 20 mg L -1 MV indicated some toxicity, which coincided with the plant pigments studies where the chlorophyll a content was lower than the control. There were little differences in the plant pigment contents between the control and those in the presence of dye (5 to 15 mg L -1 ) indicating the tolerance of AP to MV at lower concentrations. A three-layer ANN model was optimized (6 neurons in the hidden layer) and successfully predicted the phytoextraction of MV (R = 0.9989, RMSE = 0.0098). In conclusion, AP proved to be a suitable plant that could be used for the phytoextraction of MV while the ANN modelling has shown to be a reliable method for the modelling of phytoextraction of MV using AP.

An initial investigation of multidimensional flow and transverse mixing characteristics of the Ohio River near Cincinnati, Ohio

USGS Publications Warehouse

Holtschlag, David J.

2009-01-01

Two-dimensional hydrodynamic and transport models were applied to a 34-mile reach of the Ohio River from Cincinnati, Ohio, upstream to Meldahl Dam near Neville, Ohio. The hydrodynamic model was based on the generalized finite-element hydrodynamic code RMA2 to simulate depth-averaged velocities and flow depths. The generalized water-quality transport code RMA4 was applied to simulate the transport of vertically mixed, water-soluble constituents that have a density similar to that of water. Boundary conditions for hydrodynamic simulations included water levels at the U.S. Geological Survey water-level gaging station near Cincinnati, Ohio, and flow estimates based on a gate rating at Meldahl Dam. Flows estimated on the basis of the gate rating were adjusted with limited flow-measurement data to more nearly reflect current conditions. An initial calibration of the hydrodynamic model was based on data from acoustic Doppler current profiler surveys and water-level information. These data provided flows, horizontal water velocities, water levels, and flow depths needed to estimate hydrodynamic parameters related to channel resistance to flow and eddy viscosity. Similarly, dye concentration measurements from two dye-injection sites on each side of the river were used to develop initial estimates of transport parameters describing mixing and dye-decay characteristics needed for the transport model. A nonlinear regression-based approach was used to estimate parameters in the hydrodynamic and transport models. Parameters describing channel resistance to flow (Manning’s “n”) were estimated in areas of deep and shallow flows as 0.0234, and 0.0275, respectively. The estimated RMA2 Peclet number, which is used to dynamically compute eddy-viscosity coefficients, was 38.3, which is in the range of 15 to 40 that is typically considered appropriate. Resulting hydrodynamic simulations explained 98.8 percent of the variability in depth-averaged flows, 90.0 percent of the variability in water levels, 93.5 percent of the variability in flow depths, and 92.5 percent of the variability in velocities. Estimates of the water-quality-transport-model parameters describing turbulent mixing characteristics converged to different values for the two dye-injection reaches. For the Big Indian Creek dye-injection study, an RMA4 Peclet number of 37.2 was estimated, which was within the recommended range of 15 to 40, and similar to the RMA2 Peclet number. The estimated dye-decay coefficient was 0.323. Simulated dye concentrations explained 90.2 percent of the variations in measured dye concentrations for the Big Indian Creek injection study. For the dye-injection reach starting downstream from Twelvemile Creek, however, an RMA4 Peclet number of 173 was estimated, which is far outside the recommended range. Simulated dye concentrations were similar to measured concentration distributions at the first four transects downstream from the dye-injection site that were considered vertically mixed. Farther downstream, however, simulated concentrations did not match the attenuation of maximum concentrations or cross-channel transport of dye that were measured. The difficulty of determining a consistent RMA4 Peclet was related to the two-dimension model assumption that velocity distributions are closely approximated by their depth-averaged values. Analysis of velocity data showed significant variations in velocity direction with depth in channel reaches with curvature. Channel irregularities (including curvatures, depth irregularities, and shoreline variations) apparently produce transverse currents that affect the distribution of constituents, but are not fully accounted for in a two-dimensional model. The two-dimensional flow model, using channel resistance to flow parameters of 0.0234 and 0.0275 for deep and shallow areas, respectively, and an RMA2 Peclet number of 38.3, and the RMA4 transport model with a Peclet number of 37.2, may have utility for emergency-planning purposes. Emergency-response efforts would be enhanced by continuous streamgaging records downstream from Meldahl Dam, real-time water-quality monitoring, and three-dimensional modeling. Decay coefficients are constituent specific.

Ozonation of the food dye Brilliant Blue in aqueous medium: monitoring and characterization of products by direct infusion electrospray ionization coupled to high-resolution mass spectrometry.

PubMed

da Silva, Júlio César Cardoso; Bispo, Glayson Leonardo; Pavanelli, Sérgio Pinton; Afonso, Robson José de Cássia Franco; Augusti, Rodinei

2012-06-15

Dyes have been widely used to accentuate or to provide different colors to foods. However, the high concentrations of dyes in effluents from the food industries can cause serious and unpredictable damages to aquatic life in general. Furthermore, since conventional biological treatments have been shown to be ineffective, the use of advanced oxidation processes to promote the depletion of such dyes in water bodies has turned out to be mandatory. The degradation of the food dye Brilliant Blue by ozone in aqueous solution is reported herein. The overall process was monitored in real time by using direct infusion electrospray ionization high-resolution mass spectrometry in the negative ion mode, ESI(-)-HRMS. Preliminary results (visual inspection and UV-vis spectra) showed the high efficiency of ozonation in causing the decoloration of an aqueous solution of the dye whereas TOC (total organic carbon) measurements revealed that such an oxidation process was unable to promote its complete mineralization. ESI(-)-HRMS data showed that the substrate consumption occurred concomitantly with the appearance of four by-products, all of them produced by an initial attack of hydroxyl radicals (generated via the decomposition of ozone) on the two imino moieties of the dye molecule. Structures were proposed for all the by-products based mainly on the high-resolution mass measurements and on the characteristic reactivity of typical functional groups towards hydroxyl radicals. An unprecedented degradation route of Brilliant Blue by ozone in aqueous solution could thus be proposed. A greater ecotoxicity against Artemia salina was observed for the by-products than for the original dye. This indicates that the identification of by-products arising from oxidation treatments is of primary importance since such compounds can be more hazardous than the precursor itself. Copyright © 2012 John Wiley & Sons, Ltd.

Active MgO-SiO2 hybrid material for organic dye removal: A mechanism and interaction study of the adsorption of C.I. Acid Blue 29 and C.I. Basic Blue 9.

PubMed

Ciesielczyk, Filip; Bartczak, Przemysław; Zdarta, Jakub; Jesionowski, Teofil

2017-12-15

A comparative analysis was performed concerning the removal of two different organic dyes from model aqueous solution using an inorganic oxide adsorbent. The key element of the study concerns evaluation of the influence of the dyes' structure and their acid-base character on the efficiency of the adsorption process. The selection of sorbent material for this research - an MgO-SiO 2 oxide system synthesized via a modified sol-gel route - is also not without significance. The relatively high porous structure parameters of this material (A BET  = 642 m 2 /g, V p  = 1.11 mL and S p  = 9.8 nm) are a result of the proposed methodology for its synthesis. Both organic dyes (C.I. Acid Blue 29 and C.I. Basic Blue 9) were subjected to typical batch adsorption tests, including investigation of such process parameters as time, initial adsorbate concentration, adsorbent dose, pH and temperature. An attempt was also made to estimate the sorption capacity of the oxide material with respect to the analyzed organic dyes. To achieve the objectives of the research - determine the efficiency of adsorption - it was important to perform a thorough physicochemical analysis of the adsorbents (e.g. FTIR, elemental analysis and porous structure parameters). The results confirmed the significantly higher affinity of the basic dye to the oxide adsorbents compared with the acidic dye. The regeneration tests, which indirectly determine the nature of the adsorbent/adsorbate interactions, provide further evidence for this finding. On this basis, a probable mechanism of dyes adsorption on the MgO-SiO 2 oxide adsorbent was proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modeling colorimetric characteristics of ON-OFF behavior of photochromic dyes based on bis-azospiropyrans

NASA Astrophysics Data System (ADS)

Kandi, Saeideh Gorji; Nourmohammadian, Farahnaz

2013-10-01

In the present study, colorimetric characteristics of six photochromic bis-azospiropyrans based dyes are investigated. The colorimetric axes of these dyes in terms of hue, chroma and lightness are considered via UV exposure time. Results showed that, the hue angle of these dyes changes rapidly at the first times of UV irradiation, and then remains almost constant. However, chroma and lightness continuously change till about 80-240 s for different dyes. In addition, it is shown that variations of lightness and chroma by UV exposure time have an exponential trend, which can be modeled mathematically.

Time-Temperature Indicator Based on Enzymatic Degradation of Dye-Loaded Polyhydroxybutyrate.

PubMed

Anbukarasu, Preetam; Sauvageau, Dominic; Elias, Anastasia L

2017-09-01

An enzyme activated time-temperature indicator (TTI) which produces a direct colour change concomitant to variations in integrated time and temperature conditions is described. This direct colour change is realised by degrading a dye-loaded polyhydroxybutyrate (PHB) film by a depolymerase enzyme. The degradation of the PHB film by the enzyme causes the release of the dye in solution, which in turn undergoes an optical transition from clear to coloured with elapsing time. Macroscopic and microscopic optical observations confirms the uniform distribution of the dye in the PHB film. The dye release kinetics, mediated by the enzymatic reaction, are tested at different temperatures ranging from 4 to 37 °C, and are used to determine the suitability of a dye-loaded PHB as a time-temperature indicator for fresh food products based on kinetic parameters previously reported. The kinetic analysis shows that the activation energy of the dye release process is 74 kJ mol -1 , and that, at 37 °C, the dye would be totally released within 6 h. However, when incubated at 4 °C, the TTI requires in the range of 168 h (7 days) to release all the dye. These kinetics values highlight the potential of the TTI for monitoring fresh food products that have optimum shelf life around 4 °C. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measuring the Photocatalytic Breakdown of Crystal Violet Dye using a Light Emitting Diode Approach

NASA Technical Reports Server (NTRS)

Ryan, Robert E.; Underwood, Lauren W.; O'Neal, Duane; Pagnutti, Mary; Davis, Bruce A.

2009-01-01

A simple method to estimate the photocatalytic reactivity performance of spray-on titanium dioxide coatings for transmissive glass surfaces was developed. This novel technique provides a standardized method to evaluate the efficiency of photocatalytic material systems over a variety of illumination levels. To date, photocatalysis assessments have generally been conducted using mercury black light lamps. Illumination levels for these types of lamps are difficult to vary, consequently limiting their use for assessing material performance under a diverse range of simulated environmental conditions. This new technique uses an ultraviolet (UV) gallium nitride (GaN) light emitting diode (LED) array instead of a traditional black light to initiate and sustain photocatalytic breakdown. This method was tested with a UV-resistant dye (crystal violet) applied to a titanium dioxide coated glass slide. Experimental control is accomplished by applying crystal violet to both titanium dioxide coated slides and uncoated control slides. A slide is illuminated by the UV LED array, at various light levels representative of outdoor and indoor conditions, from the dye side of the slide. To monitor degradation of the dye over time, a temperature-stabilized white light LED, whose emission spectrum overlaps with the dye absorption spectrum, is used to illuminate the opposite side of the slide. Using a spectrometer, the amount of light from the white light LED transmitted through the slide as the dye degrades is monitored as a function of wavelength and time and is subsequently analyzed. In this way, the rate of degradation for photocatalytically coated versus uncoated slide surfaces can be compared. Results demonstrate that the dye absorption decreased much more rapidly on the photocatalytically coated slides than on the control uncoated slides, and that dye degradation is dependent on illumination level. For photocatalytic activity assessment purposes, this experimental configuration and methodology minimizes many external variable effects and enables small changes in absorption to be measured. This research also compares the advantages of this innovative LED light source design over traditional mercury black light systems and non- LED lamp approaches. This novel technology begins to address the growing need for a standard method that can assess the performance of photocatalytic materials before deployment for large scale, real world use.

Effects of lower limb neurodynamic mobilization on intraneural fluid dispersion of the fourth lumbar nerve root: an unembalmed cadaveric investigation

PubMed Central

Gilbert, Kerry K.; Smith, Michael P.; Sobczak, Stéphane; James, C. Roger; Sizer, Phillip S.; Brismée, Jean-Michel

2015-01-01

Objectives Manual and physical therapists incorporate neurodynamic mobilisation (NDM) to improve function and decrease pain. Little is known about the mechanisms by which these interventions affect neural tissue. The objective of this research was to assess the effects of repetitive straight leg raise (SLR) NDM on the fluid dynamics within the fourth lumbar nerve root in unembalmed cadavers. Methods A biomimetic solution (Toluidine Blue Stock 1% and Plasma) was injected intraneurally, deep to the epineurium, into the L4 nerve roots of seven unembalmed cadavers. The initial dye spread was allowed to stabilise and measured with a digital calliper. Once the initial longitudinal dye spread stabilised, an intervention strategy (repetitive SLR) was applied incorporating NDMs (stretch/relax cycles) at a rate of 30 repetitions per minute for 5 minutes. Post-intervention calliper measurements of the longitudinal dye spread were measured. Results The mean experimental posttest longitudinal dye spread measurement (1.1 ± 0.9 mm) was significantly greater (P = 0.02) than the initial stabilised pretest longitudinal dye spread measurement. Increases ranged from 0.0 to 2.6 mm and represented an average of 7.9% and up to an 18.1% increase in longitudinal dye spread. Discussion Passive NDM in the form of repetitive SLR induced a significant increase in longitudinal fluid dispersion in the L4 nerve root of human cadaveric specimen. Lower limb NDM may be beneficial in promoting nerve function by limiting or altering intraneural fluid accumulation within the nerve root, thus preventing the adverse effects of intraneural oedema. PMID:26955255

Surface grafting of zwitterionic polymers onto dye doped AIE-active luminescent silica nanoparticles through surface-initiated ATRP for biological imaging applications

NASA Astrophysics Data System (ADS)

Mao, Liucheng; Liu, Xinhua; Liu, Meiying; Huang, Long; Xu, Dazhuang; Jiang, Ruming; Huang, Qiang; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

2017-10-01

Aggregation-induced emission (AIE) dyes have recently been intensively explored for biological imaging applications owing to their outstanding optical feature as compared with conventional organic dyes. The AIE-active luminescent silica nanoparticles (LSNPs) are expected to combine the advantages both of silica nanoparticles and AIE-active dyes. Although the AIE-active LSNPs have been prepared previously, surface modification of these AIE-active LSNPs with functional polymers has not been reported thus far. In this work, we reported a rather facile and general strategy for preparation of polymers functionalized AIE-active LSNPs through the surface-initiated atom transfer radical polymerization (ATRP). The AIE-active LSNPs were fabricated via direct encapsulation of AIE-active dye into silica nanoparticles through a non-covalent modified Stöber method. The ATRP initiator was subsequently immobilized onto these AIE-active LSNPs through amidation reaction between 3-aminopropyl-triethoxy-silane and 2-bromoisobutyryl bromide. Finally, the zwitterionic 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) was selected as model monomer and grafted onto MSNs through ATRP. The characterization results suggested that LSNPs can be successfully modified with poly(MPC) through surface-initiated ATRP. The biological evaluation results demonstrated that the final SNPs-AIE-pMPC composites possess low cytotoxicity, desirable optical properties and great potential for biological imaging. Taken together, we demonstrated that AIE-active LSNPs can be fabricated and surface modified with functional polymers to endow novel functions and better performance for biomedical applications. More importantly, this strategy developed in this work could also be extended for fabrication of many other LSNPs polymer composites owing to the good monomer adoptability of ATRP.

Cold Pad-Batch dyeing method for cotton fabric dyeing with reactive dyes using ultrasonic energy.

PubMed

Khatri, Zeeshan; Memon, Muhammad Hanif; Khatri, Awais; Tanwari, Anwaruddin

2011-11-01

Reactive dyes are vastly used in dyeing and printing of cotton fibre. These dyes have a distinctive reactive nature due to active groups which form covalent bonds with -OH groups of cotton through substitution and/or addition mechanism. Among many methods used for dyeing cotton with reactive dyes, the Cold Pad Batch (CPB) method is relatively more environment friendly due to high dye fixation and non requirement of thermal energy. The dyed fabric production rate is low due to requirement of at least twelve hours batching time for dye fixation. The proposed CPB method for dyeing cotton involves ultrasonic energy resulting into a one third decrease in batching time. The dyeing of cotton fibre was carried out with CI reactive red 195 and CI reactive black 5 by conventional and ultrasonic (US) method. The study showed that the use of ultrasonic energy not only shortens the batching time but the alkalis concentrations can considerably be reduced. In this case, the colour strength (K/S) and dye fixation (%F) also enhances without any adverse effect on colour fastness of the dyed fabric. The appearance of dyed fibre surface using scanning electron microscope (SEM) showed relative straightening of fibre convolutions and significant swelling of the fibre upon ultrasonic application. The total colour difference values ΔE (CMC) for the proposed method, were found within close proximity to the conventionally dyed sample. Copyright © 2011 Elsevier B.V. All rights reserved.

Preparation of char from lotus seed biomass and the exploration of its dye removal capacity through batch and column adsorption studies.

PubMed

Nethaji, S; Sivasamy, A; Kumar, R Vimal; Mandal, A B

2013-06-01

Char was obtained from lotus seed biomass by a simple single-step acid treatment process. It was used as an adsorbent for the removal of malachite green dye (MG) from simulated dye bath effluent. The adsorbent was characterized for its surface morphology, surface functionalities, and zero point charge. Batch studies were carried out by varying the parameters such as initial aqueous pH, adsorbent dosage, adsorbent particle size, and initial adsorbate concentration. Langmuir and Freundlich isotherms were used to test the isotherm data and the Freundlich isotherm best fitted the data. Thermodynamic studies were carried out and the thermodynamic parameters such as ∆G, ∆H, and ∆S were evaluated. Adsorption kinetics was carried out and the data were tested with pseudofirst-order model, pseudosecond-order model, and intraparticle diffusion model. Adsorption of MG was not solely by intraparticle diffusion but film diffusion also played a major role. Continuous column experiments were also conducted using microcolumn and the spent adsorbent was regenerated using ethanol and was repeatedly used for three cycles in the column to determine the reusability of the regenerated adsorbent. The column data were modeled with the modeling equations such as Adam-Bohart model, Bed Depth Service Time (BDST) model, and Yoon-Nelson model for all the three cycles.

Travel Times, Streamflow Velocities, and Dispersion Rates in the Yellowstone River, Montana

USGS Publications Warehouse

McCarthy, Peter M.

2009-01-01

The Yellowstone River is a vital natural resource to the residents of southeastern Montana and is a primary source of water for irrigation and recreation and the primary source of municipal water for several cities. The Yellowstone River valley is the primary east-west transportation corridor through southern Montana. This complex of infrastructure makes the Yellowstone River especially vulnerable to accidental spills from various sources such as tanker cars and trucks. In 2008, the U.S. Geological Survey (USGS), in cooperation with the Montana Department of Environmental Quality, initiated a dye-tracer study to determine instream travel times, streamflow velocities, and dispersion rates for the Yellowstone River from Lockwood to Glendive, Montana. The purpose of this report is to describe the results of this study and summarize data collected at each of the measurement sites between Lockwood and Glendive. This report also compares the results of this study to estimated travel times from a transport model developed by the USGS for a previous study. For this study, Rhodamine WT dye was injected at four locations in late September and early October 2008 during reasonably steady streamflow conditions. Streamflows ranged from 3,490 to 3,770 cubic feet per second upstream from the confluence of the Bighorn River and ranged from 6,520 to 7,570 cubic feet per second downstream from the confluence of the Bighorn River. Mean velocities were calculated for each subreach between measurement sites for the leading edge, peak concentration, centroid, and trailing edge at 10 percent of the peak concentration. Calculated velocities for the centroid of the dye plume for subreaches that were completely laterally mixed ranged from 1.83 to 3.18 ft/s within the study reach from Lockwood Bridge to Glendive Bridge. The mean of the completely mixed centroid velocity for the entire study reach, excluding the subreach between Forsyth Bridge and Cartersville Dam, was 2.80 ft/s. Longitudinal dispersion rates of the dye plume for this study ranged from 0.06 ft/s for the subreach upstream from Forsyth Bridge to 2.25 ft/s for the subreach upstream from Calyspo Bridge for subreaches where the dye was completely laterally mixed. A relation was determined between travel time of the peak concentration and time for the dye plume to pass a site (duration). This relation can be used to estimate when the receding concentration of a potential contaminant reaches 10 percent of its peak concentration for accidental spills into the Yellowstone River. Data from this dye-tracer study were used to evaluate velocity and concentration estimates from a transport model developed as part of an earlier USGS study. Comparison of the estimated and calculated velocities for the study reach indicate that the transport model estimates the velocities of the Yellowstone River between Huntley Bridge and Glendive Bridge with reasonable accuracy. Velocities of the peak concentration of the dye plume calculated for this study averaged 10 percent faster than the most probable velocities and averaged 12 percent slower than the maximum probable velocities estimated from the transport model. Peak Rhodamine WT dye concentrations were consistently lower than the transport model estimates except for the most upstream subreach of each dye injection. The most upstream subreach of each dye injection is expected to have a higher concentration because of incomplete lateral mixing. Lower measured peak concentrations for all other sites were expected because Rhodamine WT dye deteriorates when exposed to sunlight and will sorb onto the streambanks and stream bottom. Velocity-streamflow relations developed by using routine streamflow measurements at USGS gaging stations and the transport model can be used to estimate mean streamflow velocities throughout a range of streamflows. The variation in these velocity-streamflow relations emphasizes the uncertainty in estimating the mean streamflow veloc

Benzidine-based dyes: effects of industrial practices, regulations, and world trade on the biological stains market.

PubMed

Dapson, R W

2009-06-01

One of the most sweeping changes in the dye industry since the advent of synthetic dyes grew out of the health risks associated with benzidine. Dyes made from benzidine and its derivatives were used around the world until adverse health effects become incontrovertible. Workers and family members of workers involved in production and use of benzidine-based dyes had a high incidence of bladder cancer. Following publication of several reports documenting this health hazard, dye makers in the USA, Europe, and Japan phased these dyes out of production in the 1970s. Government regulations lent legal support for these voluntary initiatives. Two strategies subsequently evolved to compensate: developed nations brought alternative substances to market while emerging countries increased production of carcinogenic dyes and sold them at discount prices around the world. Nearly all dye manufacturing now has moved away from nations whose costs of production and compliance rendered them unable to compete. The purpose of this brief review is to publicize the health risks associated with dyes made from benzidine and its congeners, and to alert all companies and end users handling these dyes for biomedical applications that composition of the product and lot-to-lot variability may be problematic because of the manufacturing and distribution practices of the countries where they are produced.

Artificial neural network (ANN) method for modeling of sunset yellow dye adsorption using zinc oxide nanorods loaded on activated carbon: Kinetic and isotherm study.

PubMed

Maghsoudi, M; Ghaedi, M; Zinali, A; Ghaedi, A M; Habibi, M H

2015-01-05

In this research, ZnO nanoparticle loaded on activated carbon (ZnO-NPs-AC) was synthesized simply by a low cost and nontoxic procedure. The characterization and identification have been completed by different techniques such as SEM and XRD analysis. A three layer artificial neural network (ANN) model is applicable for accurate prediction of dye removal percentage from aqueous solution by ZnO-NRs-AC following conduction of 270 experimental data. The network was trained using the obtained experimental data at optimum pH with different ZnO-NRs-AC amount (0.005-0.015 g) and 5-40 mg/L of sunset yellow dye over contact time of 0.5-30 min. The ANN model was applied for prediction of the removal percentage of present systems with Levenberg-Marquardt algorithm (LMA), a linear transfer function (purelin) at output layer and a tangent sigmoid transfer function (tansig) in the hidden layer with 6 neurons. The minimum mean squared error (MSE) of 0.0008 and coefficient of determination (R(2)) of 0.998 were found for prediction and modeling of SY removal. The influence of parameters including adsorbent amount, initial dye concentration, pH and contact time on sunset yellow (SY) removal percentage were investigated and optimal experimental conditions were ascertained. Optimal conditions were set as follows: pH, 2.0; 10 min contact time; an adsorbent dose of 0.015 g. Equilibrium data fitted truly with the Langmuir model with maximum adsorption capacity of 142.85 mg/g for 0.005 g adsorbent. The adsorption of sunset yellow followed the pseudo-second-order rate equation. Copyright © 2014 Elsevier B.V. All rights reserved.

Artificial neural network (ANN) method for modeling of sunset yellow dye adsorption using zinc oxide nanorods loaded on activated carbon: Kinetic and isotherm study

NASA Astrophysics Data System (ADS)

Maghsoudi, M.; Ghaedi, M.; Zinali, A.; Ghaedi, A. M.; Habibi, M. H.

2015-01-01

In this research, ZnO nanoparticle loaded on activated carbon (ZnO-NPs-AC) was synthesized simply by a low cost and nontoxic procedure. The characterization and identification have been completed by different techniques such as SEM and XRD analysis. A three layer artificial neural network (ANN) model is applicable for accurate prediction of dye removal percentage from aqueous solution by ZnO-NRs-AC following conduction of 270 experimental data. The network was trained using the obtained experimental data at optimum pH with different ZnO-NRs-AC amount (0.005-0.015 g) and 5-40 mg/L of sunset yellow dye over contact time of 0.5-30 min. The ANN model was applied for prediction of the removal percentage of present systems with Levenberg-Marquardt algorithm (LMA), a linear transfer function (purelin) at output layer and a tangent sigmoid transfer function (tansig) in the hidden layer with 6 neurons. The minimum mean squared error (MSE) of 0.0008 and coefficient of determination (R2) of 0.998 were found for prediction and modeling of SY removal. The influence of parameters including adsorbent amount, initial dye concentration, pH and contact time on sunset yellow (SY) removal percentage were investigated and optimal experimental conditions were ascertained. Optimal conditions were set as follows: pH, 2.0; 10 min contact time; an adsorbent dose of 0.015 g. Equilibrium data fitted truly with the Langmuir model with maximum adsorption capacity of 142.85 mg/g for 0.005 g adsorbent. The adsorption of sunset yellow followed the pseudo-second-order rate equation.

Polyester Fabric's Fluorescent Dyeing in Supercritical Carbon Dioxide and its Fluorescence Imaging.

PubMed

Xiong, Xiaoqing; Xu, Yanyan; Zheng, Laijiu; Yan, Jun; Zhao, Hongjuan; Zhang, Juan; Sun, Yanfeng

2017-03-01

As one of the most important coumarin-like dyes, disperse fluorescent Yellow 82 exhibits exceptionally large two-photon effects. Here, it was firstly introduced into the supercritical CO 2 dyeing polyester fabrics in this work. Results of the present work showed that the dyeing parameters such as the dyeing time, pressure and temperature had remarkable influences on the color strength of fabrics. The optimized dyeing condition in supercritical CO 2 dyeing has been proposed that the dyeing time was 60 min; the pressure was 25 MPa and the temperature was 120 °C. As a result, acceptable products were obtained with the wash and rub fastness rating at 5 or 4-5. The polyester fabrics dyed with fluorescent dyes can be satisfied for the requirement of manufacturing warning clothing. Importantly, the confocal microscopy imaging technology was successfully introduced into textile fields to observe the distribution and fluorescence intensity of disperse fluorescent Yellow 82 on polyester fabrics. As far as we know, this is the first report about supercritical CO 2 dyeing polyester fabrics based on disperse fluorescent dyes. It will be very helpful for the further design of new fluorescent functional dyes suitable for supercritical CO 2 dyeing technique.

Synthesis, characterization, and reactivity of cellulose modified nano zero-valent iron for dye discoloration

NASA Astrophysics Data System (ADS)

Wang, Xiangyu; Wang, Pei; Ma, Jun; Liu, Huiling; Ning, Ping

2015-08-01

Nano zero-valent iron (NZVI) was innovatively and successfully modified by using hydroxyethyl cellulose (HEC) and hydroxypropylmethyl cellulose (HPMC) as dispersants. The systematic characterization observations (including XRD, SEM and TEM) illustrate that, compared with bare nano zero-valent iron particles (BNZVI), the particle sizes of hydroxyethyl cellulose modified (ENZVI) and hydroxypropylmethyl cellulose modified (PNZVI) were decreased, while the dispersity and antioxidizability of ENZVI and PNZVI particles were increased. The discoloration efficiencies of ENZVI, PNZVI, and BNZVI were compared by using dyes (including orange II, methyl orange, methyl blue, and methylene blue) as target pollutant. The results show that both the discoloration efficiency and reaction rate of ENZVI and PNZVI are higher than that of BNZVI. In addition, effects of dispersant content, dye type, pH value, initial dye concentration, iron dosage, and reaction temperature on discoloration efficiencies were studied. The results show that discoloration efficiency was decreased by increasing initial pH value and dye concentration, and it was increased with the increase the iron dosage and reaction temperature. Under optimized NZVI addition of 0.7 g L-1, the discoloration efficiencies of ENZVI and PNZVI were increased to 96.33% and 98.62%, respectively. And the possible discoloration pathway and dispersant modification mechanism of NZVI were discussed. This study suggests hydroxyethyl cellulose and hydroxypropylmethyl cellulose dispersed NZVI can be utilized as a promising modified nano-material for degradation of dye wastewater.

Effect of sintering time on the performance of turmeric dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Basuki, Hidajat, R. Lullus Lambang G.; Suyitno, Kristiawan, Budi; Rachmanto, Rendy Adhi

2017-01-01

This study reports the effect of sintering time on the performance of the dye-sensitized solar cells with turmeric dyes as sensitizers. Sintering TiO2 semiconductors were conducted at a temperature of 450°C for 30, 50, 90, 120, 150, and 180 minutes. The natural dye was extracted from dried turmeric powders with ethanol solvent. The results show that size of grains and the opening area of TiO2 semiconductor depended on the sintering time. The improvement of the properties of TiO2 semiconductor allowed more turmeric dyes were adsorbed by the semiconductors and then improved the performance of solar cells. The sintering time of 150 minutes produced large grains with an average diameter of 68.87 nm, and a porosity area of 26.51% caused the performance of DSSCs was the highest among other sintering time. The Voc, Jsc, and efficiency of DSSCs with turmeric-based natural dyes 0.64 V, 0.47 mA/cm2, and 0.2%, respectively.

The Comparative Study on the Rapid Decolorization of Azo, Anthraquinone and Triphenylmethane Dyes by Anaerobic Sludge

PubMed Central

Cui, Daizong; Zhang, Hao; He, Rubao; Zhao, Min

2016-01-01

An anaerobic sludge (AS), capable of decolorizing a variety of synthetic dyes, was acclimated and is reported here. The sludge presented a much better dye decolorizing ability than that of different individual strains. A broad spectrum of dyes could be decolorized by the sludge. Continuous decolorization tests showed that the sludge exhibited the ability to decolorize repeated additions of dye. The chemical oxygen demand (COD) removal rate of the dye wastewater reached 52% after 12 h of incubation. Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) profiles revealed that the microbial community changed as a result of varying initial concentrations of dyes. Phylogenetic analysis indicated that microbial populations in the sludge belonged to the phyla Acidobacteria, Firmicutes, Bacteroidetes, Chloroflexi and Proteobacteria. The degradation products of the three types of dye were identified. For azo dyes, the anaerobic sludge converted Methyl Orange to N,N-dimethylbenzene-1,4-diamine and 4-aminobenzenesulfonic acid; for triphenylmethane dyes, after Malachite Green was decolorized, the analyzed products were found to be a mixture of N,N-dimethylbenzenamine, 3-dimethyl-aminophenol and 4-dimethylaminobenzophenone; for anthraquinone dyes, two products (acetophenone and 2-methylbenzoic acid) were observed after Reactive Blue 19 decolorization. Together, these results suggest that the anaerobic sludge has promising potential for use in the treatment of industrial wastewater containing various types of dyes. PMID:27801853

Magnetically modified sheaths of Leptothrix sp. as an adsorbent for Amido black 10B removal

NASA Astrophysics Data System (ADS)

Angelova, Ralitsa; Baldikova, Eva; Pospiskova, Kristyna; Safarikova, Mirka; Safarik, Ivo

2017-04-01

The goal of this study was to assess the biosorption of Amido black 10B dye from aqueous solutions on magnetically modified sheaths of Leptothrix sp. in a batch system. The magnetic modification of the sheaths was performed using both microwave synthesized iron oxide nano- and microparticles and perchloric acid stabilized ferrofluid. The native and both magnetically modified sheaths were characterized by SEM. Various parameters significantly affecting the adsorption process, such as pH, contact time, temperature and initial concentration, were studied in detail using the adsorbent magnetized by both methods. The highest adsorption efficiency was achieved at pH 2. The maximum adsorption capacities of both types of magnetized material at room temperature were found to be 339.2 and 286.1 mg of dye per 1 g of ferrofluid modified and microwave synthesized particles modified adsorbent, respectively. Thermodynamic study of dye adsorption revealed a spontaneous and endothermic process in the temperature range between 279.15 and 313.15 K. The data were fitted to various equilibrium and kinetic models. Experimental data matched well with the pseudo-second-order kinetics and Freundlich isotherm model. The Leptothrix sheaths have excellent efficacy for dye adsorption. This material can be used as an effective, low-cost adsorbent.

Green synthesis of palm oil mill effluent-based graphenic adsorbent for the treatment of dye-contaminated wastewater.

PubMed

Teow, Yeit Haan; Nordin, Nadzirah Ilyiani; Mohammad, Abdul Wahab

2018-05-12

Textile wastewater contains methylene blue (MB), a major coloring agent in textile industry. Activated carbon (AC) is the most widely used adsorbent in removing dyes from industrial wastewater. However, high production cost of AC is the major obstacle for its wide application in dye wastewater treatment. In this study, a sustainable approach in synthesizing graphenic adsorbent from palm oil mill effluent (POME), a potential carbonaceous source, has been explored. This new development in adsorption technique is considered as green synthesis as it does not require any binder during the synthesis process, and at the same time, it helps to solve the bottleneck of palm oil industry as POME is the main cause contributed to Malaysia's water pollution problem. The synthesized GSC was characterized through XRD, FESEM, and EDX. The adsorption performance of the synthesized GSC was evaluated by adsorption of MB. The effect of initial concentration of synthetic MB solution (1-20 mg/L) and weight of GSC (5-20 g) were investigated. A remarkable change in color of synthetic MB solution from blue to crystal clear was observed at the end of adsorption study. High efficiency of the synthesized GSC for dye-contaminated wastewater treatment is concluded.

New energy transfer dyes for DNA sequencing.

PubMed Central

Lee, L G; Spurgeon, S L; Heiner, C R; Benson, S C; Rosenblum, B B; Menchen, S M; Graham, R J; Constantinescu, A; Upadhya, K G; Cassel, J M

1997-01-01

We have synthesized a set of four energy transfer dyes and demonstrated their use in automated DNA sequencing. The donor dyes are the 5- or 6-carboxy isomers of 4'-aminomethylfluorescein and the acceptor dyes are a novel set of four 4,7-dichloro-substituted rhodamine dyes which have narrower emission spectra than the standard, unsubstituted rhodamines. A rigid amino acid linker, 4-aminomethylbenzoic acid, was used to separate the dyes. The brightness of each dye in an automated sequencing instrument equipped with a dual line argon ion laser (488 and 514 nm excitation) was 2-2.5 times greater than the standard dye-primers with a 2 times reduction in multicomponent noise. The overall improvement in signal-to-noise was 4- to 5-fold. The utility of the new dye set was demonstrated by sequencing of a BAC DNA with an 80 kb insert. Measurement of the extinction coefficients and the relative quantum yields of the dichlororhodamine components of the energy transfer dyes showed their values were reduced by 20-25% compared with the dichlororhodamine dyes alone. PMID:9207029

Photophysical studies on the interaction of acridinedione dyes with universal protein denaturant: guanidine hydrochloride.

PubMed

Kumaran, R; Varalakshmi, T; Malar, E J Padma; Ramamurthy, P

2010-09-01

Photophysical studies of photoinduced electron transfer (PET) and non-PET based acridinedione dyes with guanidine hydrochloride (GuHCl) were carried out in water and methanol. Addition of GuHCl to photoinduced electron transfer (PET) based acridinedione dye (ADR 1) results in a fluorescence enhancement, whereas a non-PET based dye (ADR 2) shows no significant change in the fluorescence intensity and lifetime. Addition of GuHCl to ADR 1 dye in methanol results in single exponential decay behaviour, on the contrary a biexponential decay pattern was observed on the addition of GuHCl in water. Absorption and emission spectral studies of ADR 1 dye interaction with GuHCl reveals that the dye molecule is not in the protonated form in aqueous GuHCl solution, and the dye is confined to two distinguishable microenvironment in the aqueous phase. A large variation in the microenvironment around the dye molecule is created on the addition of GuHCl and this was ascertained by time-resolved area normalized emission spectroscopy (TRANES) and time-resolved emission spectroscopy (TRES). The dye molecule prefers to reside in the hydrophobic microenvironment, rather in the hydrophilic aqueous phase is well emphasized by time-resolved fluorescence lifetime studies. The mechanism of fluorescence enhancement of ADR 1 dye by GuHCl is attributed to the suppression of the PET process occurring through space.

Evaluation of Aluminium Dross as Adsorbent for Removal of Carcinogenic Congo Red Dye in Wastewater

NASA Astrophysics Data System (ADS)

Zakaria, Mohamad Zulfika Hazielim b.; Zauzi, Nur Syuhada Ahmad; Baini, Rubiyah; Sutan, Norsuzailina Mohamed; Rezaur Rahman, Md

2017-06-01

In this study, aluminium dross waste generated from aluminium smelting industries was employed as adsorbent in removing of congo red dye in aqueous solution. The raw aluminium dross as adsorbent was characterized using Scanning Electron Microscope (SEM), Brunauer-Emmett-Teller (BET) for surface area and X-Ray Fluorescence (XRF) Spectroscopy. Adsorption experiments were carried out by batch system at different adsorbent mass, pH, and initial dye concentration. The results showed that the per cent removal of dye increased as adsorbent mass increased. It was found that 0.4 gram of adsorbent can remove approximately 100 % of dye at pH 9 for dye concentration 20 and 40 ppm. Therefore, it can be concluded that raw aluminium dross without undergone any treatment can be effectively used for the adsorption of congo red in textile wastewater related industries.

A multi-directional tracer test in the fractured Chalk aquifer of E. Yorkshire, UK.

PubMed

Hartmann, S; Odling, N E; West, L J

2007-12-07

A multi-borehole radial tracer test has been conducted in the confined Chalk aquifer of E. Yorkshire, UK. Three different tracer dyes were injected into three injection boreholes and a central borehole, 25 m from the injection boreholes, was pumped at 330 m(3)/d for 8 days. The breakthrough curves show that initial breakthrough and peak times were fairly similar for all dyes but that recoveries varied markedly from 9 to 57%. The breakthrough curves show a steep rise to a peak and long tail, typical of dual porosity aquifers. The breakthrough curves were simulated using a 1D dual porosity model. Model input parameters were constrained to acceptable ranges determined from estimations of matrix porosity and diffusion coefficient, fracture spacing, initial breakthrough times and bulk transmissivity of the aquifer. The model gave equivalent hydraulic apertures for fractures in the range 363-384 microm, dispersivities of 1 to 5 m and matrix block sizes of 6 to 9 cm. Modelling suggests that matrix block size is the primary controlling parameter for solute transport in the aquifer, particularly for recovery. The observed breakthrough curves suggest results from single injection-borehole tracer tests in the Chalk may give initial breakthrough and peak times reasonably representative of the aquifer but that recovery is highly variable and sensitive to injection and abstraction borehole location. Consideration of aquifer heterogeneity suggests that high recoveries may be indicative of a high flow pathway adjacent, but not necessarily connected, to the injection and abstraction boreholes whereas low recoveries may indicate more distributed flow through many fractures of similar aperture.

A modified commercial ultrasound scanner used for in vivo photoacoustic imaging of nude mice injected with non-targeted contrast agents

NASA Astrophysics Data System (ADS)

Jankovic, Ladislav; Shahzad, Khalid; Wang, Yao; Burcher, Michael; Scholle, Frank-Detlef; Hauff, Peter; Mofina, Sabine; Skobe, Mihaela

2008-02-01

Photoacoustic (PA) experiments were performed using a modified commercial ultrasound scanner equipped with an array transducer and a Nd:YAG pumped OPO laser. The contrast agent SIDAG (Bayer Schering Pharma AG, Germany), used to enhance the optical absorption, demonstrated an expected pharmacokinetic behavior of the dye in the tumor and in the bladder of the nude mice. A typical behavior in the tumor consisted of an initial linear increase in PA signal followed by an exponential decay. PA signal approached the pre-injection level after about one hour following the dye injection, which was consistent with the behavior for such contrast agents when used in other imaging modalities, such as fluorescence imaging. The in-vivo spectral PA data from the mouse bladder, conducted 1.5 hours after the dye injection, clearly demonstrated presence of the dye. The multi-spectral PA data was obtained at 760nm, 784nm and 850nm laser excitations. The PA intensities obtained at these three wavelengths accurately matched the dye absorption spectrum. In addition, in the kidney, a clearance organ for this contrast agent, both in-vivo and ex-vivo results demonstrated a significant increase (~ 40%) in the ratio of PA signal at 760nm (the peak of the dye absorption) relative to the signal at 850nm (<1% absorption), indicating significant amounts of the dye in this organ. Our initial results confirm the desired photoacoustic properties of the contrast agent, indicating its great potential to be used for imaging with a commercial array-based ultrasound scanner.

Removal of malachite green dye from aqueous solution using mesoporous silica synthesized from 1-octyl-3-methylimidazolium chloride ionic liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ekka, Basanti; Nayak, Soumitra Ranjan; Dash, Priyabrat, E-mail: dashp@nitrkl.ac.in, E-mail: rkpatel@nitrkl.ac.in

2016-04-13

In this research, mesoporous silica was synthesized via a modified sol-gel route using 1-octyl-3-methylimidazolium chloride and was employed to remove malachite green (MG) dye from aqueous solution. Subsequently, this material was characterized and identified by different techniques such as Fourier transform infrared spectroscopy (FT-IR), N{sub 2} adsorption-desorption method, scanning electron microscopy (SEM), and thermosgravimetric analysis (TGA). Unique properties such as high surface area and pore diameter, in addition to highly reactive atoms and presence of various functional groups make the mesoporous silica possible for efficient removal of malachite green (MG). In batch experimental set-up, optimum conditions for quantitative removal ofmore » MG by mesoporous silica was attained by varying different variables such as adsorbent dosage, initial dye concentration, contact time, and pH. Optimum values were set as pH of 8.0, 0.5 g of adsorbent at contact time of 120 min. The adsorption of MG follows the pseudo-second-order rate equation. Equilibrium data fitted well with the Freundlich model at all amount of adsorbent, while maximum adsorption capacity was 5.981 mg g{sup −}1 for 0.5 g mesoporous silica synthesized in IL.« less

Photoinduced random molecular reorientation by nonradiative energy relaxation: An experimental test

NASA Astrophysics Data System (ADS)

Manzo, C.; Paparo, D.; Marrucci, L.

2004-11-01

By measuring the time-resolved fluorescence depolarization as a function of light excitation wavelength we address the question of a possible photoinduced orientational randomization of amino-anthraquinone dyes in liquid solutions. We find no significant dependence within the experimental uncertainties of both the initial molecule anisotropy and of the subsequent rotational diffusion dynamics on the photon energy. This indicates that this effect, if present, must be very small. A simple model of photoinduced local heating and corresponding enhanced rotational diffusion is in accordance with this result. This null result rules out some recent proposals that photoinduced local heating may contribute significantly to molecular reorientation effects in different materials. A small but statistically significant effect of photon energy is instead found in the excited-state lifetime of the dye.

Batch and continuous (fixed-bed column) biosorption of crystal violet by Artocarpus heterophyllus (jackfruit) leaf powder.

PubMed

Saha, Papita Das; Chakraborty, Sagnik; Chowdhury, Shamik

2012-04-01

In this study, batch and fixed-bed column experiments were performed to investigate the biosorption potential of Artocarpus heterophyllus (jackfruit) leaf powder (JLP) to remove crystal violet (CV) from aqueous solutions. Batch biosorption studies were carried out as a function of solution pH, contact time, initial dye concentration and temperature. The biosorption equilibrium data showed excellent fit to the Langmuir isotherm model with maximum monolayer biosorption capacity of 43.39 mg g(-1) at pH 7.0, initial dye concentration=50 mg L(-1), temperature=293 K and contact time=120 min. According to Dubinin-Radushkevich (D-R) isotherm model, biosorption of CV by JLP was chemisorption. The biosorption kinetics followed the pseudo-second-order kinetic model. Thermodynamic analysis revealed that biosorption of CV from aqueous solution by JLP was a spontaneous and exothermic process. In order to ascertain the practical applicability of the biosorbent, fixed-bed column studies were also performed. The breakthrough time increased with increasing bed height and decreased with increasing flow rate. The Thomas model as well as the BDST model showed good agreement with the experimental results at all the process parameters studied. It can be concluded that JLP is a promising biosorbent for removal of CV from aqueous solutions. Copyright © 2011 Elsevier B.V. All rights reserved.

Natural dye extracted from karkadah and its application in dye-sensitized solar cells: experimental and density functional theory study.

PubMed

Reda, S M; Soliman, K A

2016-02-01

This work presents an experimental and theoretical study of cyanidin natural dye as a sensitizer for ZnO dye-sensitized solar cells. ZnO nanoparticles were prepared using ammonia and oxalic acid as a capping agent. The calculated average size of the synthesized ZnO with different capping agents was found to be 32.1 nm. Electronic properties of cyanidin and delphinidin dye were studied using density functional theory (DFT) and time-dependent DFT with a B3LYP/6-31G(d,p) level. By comparing the theoretical results with the experimental data, the cyanidin dye can be used as a sensitizer in dye-sensitized solar cells. An efficiency of 0.006% under an AM-1.5 illumination at 100  mW/cm(2) was attained. The influence of dye adsorption time on the solar cell performance is discussed.

Blending DNA binding dyes to improve detection in real-time PCR.

PubMed

Jansson, Linda; Koliana, Marianne; Sidstedt, Maja; Hedman, Johannes

2017-03-01

The success of real-time PCR (qPCR) analysis is partly limited by the presence of inhibitory compounds in the nucleic acid samples. For example, humic acid (HA) from soil and aqueous sediment interferes with amplification and also quenches the fluorescence of double-stranded (ds) DNA binding dyes, thus hindering amplicon detection. We aimed to counteract the HA fluorescence quenching effect by blending complementary dsDNA binding dyes, thereby elevating the dye saturation levels and increasing the fluorescence signals. A blend of the four dyes EvaGreen, ResoLight, SYBR Green and SYTO9 gave significantly higher fluorescence intensities in the presence and absence of HA, compared with the dyes applied separately and two-dye blends. We propose blending of dyes as a generally applicable means for elevating qPCR fluorescence signals and thus enabling detection in the presence of quenching substances.

Optical properties of cyanine dyes in nanotubes of chrysotile asbestos

NASA Astrophysics Data System (ADS)

Starovoytov, Anton A.; Vartanyan, Tigran A.; Belotitskii, Vladimir I.; Kumzerov, Yuri A.; Sysoeva, Anna A.

2017-08-01

Optical properties of cyanine dye molecules incorporated in nanotubes of natural chrysotile asbestos are studied. The absorption and fluorescence spectra of dye in asbestos have the similar shapes as in the ethanol solution, apart from small blue shift of the maxima. The Stokes shift in asbestos is smaller than in the ethanol solution. The fluorescence decay times of the dyes in asbestos nanotubes are found to be larger than that in the case of thin films of the same dyes formed on the transparent dielectric supports. This observation is rationalized in terms of the stereoisomerization hindrance in the excited electronic state of dye molecules. At the same time linear dichroism and fluorescence anisotropy observed in the experiment indicate that the embedded dye molecules are well-isolated monomer oriented predominantly along asbestos nanotubes.

Optical determination of charge transfer times from indoline dyes to ZnO in solid state dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Meyenburg, I.; Hofeditz, N.; Ruess, R.; Rudolph, M.; Schlettwein, D.; Heimbrodt, W.

2018-05-01

We studied the electron transfer at the interface of organic-inorganic hybrids consisting of indoline derivatives (D149 and D131) on ZnO substrates using a new optical method. We revealed the electron transfer times from the excited dye, e.g. the excitons formed in the dye aggregates to the ZnO substrate by analyzing the photoluminescence transients of the excitons after femtosecond excitation and applying kinetic model calculations. We reveal the changes of the electron transfer times by applying electrical bias. Pushing the Fermi energy of the ZnO substrate towards the excited dye level the transfer time gets longer and eventually the electron transfer is suppressed. The level alignment between the excited dye state and the ZnO Fermi-level is estimated. The excited state of D131 is about 100 meV higher than the respective state of D149 compared to the ZnO conduction band. This leads to shorter electron transfer times and eventually to higher quantum efficiencies of the solar cells.

Batchwise dyeing of bamboo cellulose fabric with reactive dye using ultrasonic energy.

PubMed

Larik, Safdar Ali; Khatri, Awais; Ali, Shamshad; Kim, Seong Hun

2015-05-01

Bamboo is a regenerated cellulose fiber usually dyed with reactive dyes. This paper presents results of the batchwise dyeing of bamboo fabric with reactive dyes by ultrasonic (US) and conventional (CN) dyeing methods. The study was focused at comparing the two methods for dyeing results, chemicals, temperature and time, and effluent quality. Two widely used dyes, CI Reactive Black 5 (bis-sulphatoethylsulphone) and CI Reactive Red 147 (difluorochloropyrimidine) were used in the study. The US dyeing method produced around 5-6% higher color yield (K/S) in comparison to the CN dyeing method. A significant savings in terms of fixation temperature (10°C) and time (15 min), and amounts of salt (10 g/L) and alkali (0.5-1% on mass of fiber) was realized. Moreover, the dyeing effluent showed considerable reductions in the total dissolved solids content (minimum around 29%) and in the chemical oxygen demand (minimum around 13%) for the US dyebath in comparison to the CN dyebath. The analysis of colorfastness tests demonstrated similar results by US and CN dyeing methods. A microscopic examination on the field emission scanning electron microscope revealed that the US energy did not alter the surface morphology of the bamboo fibers. It was concluded that the US dyeing of bamboo fabric produces better dyeing results and is a more economical and environmentally sustainable method as compared to CN dyeing method. Copyright © 2014 Elsevier B.V. All rights reserved.

Novel biosynthesized silver nanoparticles from cobweb as adsorbent for Rhodamine B: equilibrium isotherm, kinetic and thermodynamic studies

NASA Astrophysics Data System (ADS)

Azeez, Luqmon; Lateef, Agbaje; Adebisi, Segun A.; Oyedeji, Abdulrasaq O.

2018-03-01

This study has investigated the adsorption of Rhodamine B (Rh-B) dye on novel biosynthesized silver nanoparticles (AgNPs) from cobweb. The effects of contact time, initial pH, initial dye concentration, adsorbent dosage and temperature were studied on the removal of Rh-B and they significantly affected its uptake. Adsorption isotherms were evaluated using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The adsorption process was best described by Langmuir isotherm with R 2 of 0.9901, indicating monolayer adsorption. The maximum adsorption capacity ( q max) of 59.85 mg/g showed that it has relatively high performance, while adsorption intensity showed a favourable adsorption process. Pseudo-second-order kinetics fitted best the rate of adsorption and intra-particle diffusion revealed both surface adsorption and intra-particle diffusion-controlled adsorption process. Negative values of thermodynamic parameters (Δ H°, Δ S° and Δ G°) indicated an exothermic and spontaneous adsorption process. The mean sorption energy ( E) and activation energy ( E a) suggested the uptake of Rh-B onto AgNPs was chemical in nature (chemosorption).

Razor clam (Ensis directus) shell as a low-cost adsorbent for the removal of Congo red and Rhodamine B dyes from aqueous solution

NASA Astrophysics Data System (ADS)

Areibat, Lila Elamari Mohamed; Kamari, Azlan

2017-05-01

Wastewater originating from industrial effluents contains many types of pollutants including dyes. Anionic and cationic dyes are very toxic and they can cause several problems to aquatic system. In present study, razor clam shell was used as a potential adsorbent to remove two classes of dyes, namely anionic (Congo red, CR) and cationic (Rhodamine B, RB) dyes from aqueous solution. Batch adsorption experiments were performed to study the effects of three experimental parameters, namely solution pH, adsorbent dosage and initial dye concentration, on adsorption capacity of CR and RB onto razor clam shell. Results indicated that pH 2.0 was optimum pH for adsorbent to adsorb both CR and RB. At an initial concentration of 20 mg/L, the removal percentages of CR and RB were 97% and 38%, respectively. The Freundlich and Langmuir isotherm models were used to describe adsorption behaviour of CR and RB, as well as the relationship between adsorbent and adsorbate. The adsorption equilibrium data were well fitted to Freundlich isotherm model. The separation factor (RL) constants suggest that both CR and RB were favourably adsorbed by razor clam shell. Razor clam shell was characterised by using two techniques, namely Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectrometry (FTIR). Overall, this study suggests that razor clam shell has great potential to be an alternative to expensive adsorbents.

Modification of mutagenesis initiated by ultraviolet light through posttreatment of bacteria with basic dyes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Witkin, E M

1961-12-01

Post treatment with basic dyes, in concentrations that retard cell division, was found to influence the tnduction of mutations to prototrophy by UV light in a tyrosine-requirtng strain of E.Coli. Pyronin, which is unique among the dyes in tts selective affinity for RNA, was found to duplicate the effects of chloramphenicol or amino acfd deprtvatfon in causfng the rapid and irreversible loss of potential prototrophs (mutation frequency decline, or MFD). Acriflavtne, methyl green. crystal violet, methylene blue, and toluidine blue, all of which are known to combine with DNA, delay or retard the occurrence of MFD under conditions of aminomore » acid deprivation. When acriflavine is removed from its combination with cellular components by the addition of an excess of sodium deoxyrtbonucleate, MFD begins promptly. The same basic dyes that delay MFD were also found to interfere with the fixation of mutations (MF) in an amino acid- enriched medium, and to cause marked enhancement of the mutagenic potency of low doses of UV light. While showing no independent mutagenic activity for unirradiated bacteria, all the dyes except pyronin increased the yield of induced mutations signtficantly when added to the enriched medium upon which trradiated bacteria were incubated.These results were interpreted as evidence that UV light initiates mutagenesis by producing unstable changas directly in genic DNA. MFD is interpreted as a repair process, blocked by the machinery of RNA and protein synthesis and by the presence of certain basic dyes.« less

Adsorption and desorption of cationic malachite green dye on cellulose nanofibril aerogels.

PubMed

Jiang, Feng; Dinh, Darren M; Hsieh, You-Lo

2017-10-01

Ultra-light aerogels have been assembled from cellulose nanofibrils into hierarchically macroporous (several hundred μm) honeycomb cellular structure surrounded with mesoporous (8-60nm) thin walls. The high specific surface (193m 2 /g) and surface carboxyl content (1.29mmol/g) of these aerogels were demonstrated to be highly capable of removing cationic malachite green (MG) dye from aqueous media. The rapid MG adsorption was driven by electrostatic interactions and followed a pseudo-second-order adsorption kinetic and monolayer Langmuir adsorption isotherm. At a low 1:5mg/mL aerogel/MG ratio, both initial MG adsorption rate (2.3-59.8mgg -1 min -1 ) and equilibrium adsorption capacity (53.0-203.7mgg -1 ) increased with increasing initial MG concentrations from 10 to 200mg/L, reaching a maximum adsorption of 212.7mgg -1 . The excellent dye removal efficiency was demonstrated by complete MG removal through four repetitive adsorptions at a low 1:5mg/mL aerogel/MG ratio and 10mg/L dye concentration as well as 92% MG adsorption in a single batch at one order of magnitude higher10:5mg/mL aerogel/MG ratio and 100mg/L dye concentration. The adsorbed MG in aerogels could be desorbed in aqueous media by increasing ionic strength, demonstrating facile recovery of both dye and aerogel as well as the robust capability of this aerogel for repetitive applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Studies on Nano-Engineered TiO2 Photo Catalyst for Effective Degradation of Dye

NASA Astrophysics Data System (ADS)

Sowmya, S. R.; Madhu, G. M.; Hashir, Mohammed

2018-02-01

All Heterogeneous photo catalysis employing efficient photo-catalyst is the advanced dye degradation technology for the purification of textile effluent. The present work focuses on Congo red dye degradation employing synthesized Ag doped TiO2 nanoparticles as photocatalyst which is characterized using SEM, XRD and FTIR. Studies are conducted to study the effect of various parameters such as initial dye concentration, catalyst loading and pH of solution. Ag Doped TiO2 photocatalyst improve the efficacy of TiO2 by reducing high band gap and electron hole recombination of TiO2. The reaction kinetics is analyzed and the process is found to follow pseudo first order kinetics.

Optically sectioned wide-field fluorescence lifetime imaging endoscopy enabled by structured illumination (Conference Presentation)

NASA Astrophysics Data System (ADS)

Hinsdale, Taylor; Malik, Bilal H.; Rico-Jimenez, Jose J.; Jo, Javier A.; Maitland, Kristen C.

2016-03-01

We present a wide-field fluorescence lifetime imaging (FLIM) system with optical sectioning by structured illumination microscopy (SIM). FLIM measurements were made using a time gated ICCD camera in conjunction with a pulsed nitrogen dye laser operating at 450 nm. Intensity images were acquired at multiple time delays from a trigger initiated by a laser pulse to create a wide-field FLIM image, which was then combined with three phase SIM to provide optical sectioning. Such a mechanism has the potential to increase the reliability and accuracy of the FLIM measurements by rejecting background intensity. SIM also provides the opportunity to create volumetric FLIM images with the incorporation of scanning mechanisms for the sample plane. We present multiple embodiments of such a system: one as a free space endoscope and the other as a fiber microendoscope enabled by the introduction of a fiber bundle. Finally, we demonstrate the efficacy of such an imaging system by imaging dyes embedded in a tissue phantom.

Evaluation of a Centyrin-Based Near-Infrared Probe for Fluorescence-Guided Surgery of Epidermal Growth Factor Receptor Positive Tumors.

PubMed

Mahalingam, Sakkarapalayam M; Dudkin, Vadim Y; Goldberg, Shalom; Klein, Donna; Yi, Fang; Singhal, Sunil; O'Neil, Karyn T; Low, Philip S

2017-11-15

Tumor-targeted near-infrared fluorescent dyes have the potential to improve cancer surgery by enabling surgeons to locate and resect more malignant lesions where good visualization tools are required to ensure complete removal of malignant tissue. Although the tumor-targeted fluorescent dyes used in humans to date have been either small organic molecules or high molecular weight antibodies, low molecular weight protein scaffolds have attracted significant attention because they penetrate solid tumors almost as efficiently as small molecules, but can be infinitely mutated to bind almost any antigen. Here we describe the use of a 10 kDa protein scaffold, a Centyrin, to target a near-infrared fluorescent dye to tumors that overexpress the epidermal growth factor receptor (EGFR) for fluorescence-guided surgery (FGS). We have developed and optimized the dose and time required for imaging small tumor burdens with minimal background fluorescence in real-time fluorescence-guided surgery of EGFR-expressing tumor xenografts in murine models. We demonstrate that the Centyrin-near-infrared dye conjugate (CNDC) binds selectively to human EGFR + cancer cells with an EC 50 of 2 nM, localizes to EGFR + tumor xenografts in athymic nude mice and that uptake of the dye in xenografts is significantly reduced when EGFR are blocked by preinjection of excess unlabeled Centyrin. Taken together, these data suggest that CNDCs can be used for intraoperative identification and surgical removal of EGFR-expressing lesions and that Centyrins targeted to other tumor-specific antigens should prove similarly useful in fluorescence guided surgery of cancer. In addition, we demonstrate that the CNDC is detected in the NIR region of the spectrum and can be utilized for fluorescence-guided surgery (FGS). In addition, we propose that with its eventual complete clearance from EGFR-negative tissues and its quantitative retention in the tumor mass for >24 h, a Centyrin-targeted NIR dye should provide excellent tumor contrast when injected at least 6-8 h before initiation of cancer surgery in human patients.

Novel bio-electro-Fenton technology for azo dye wastewater treatment using microbial reverse-electrodialysis electrolysis cell.

PubMed

Li, Xiaohu; Jin, Xiangdan; Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

2017-03-01

Development of sustainable technologies for treatment of azo dyes containing wastewaters has long been of great interest. In this study, we proposed an innovative concept of using microbial reverse-electrodialysis electrolysis cell (MREC) based Fenton process to treat azo dye wastewater. In such MREC-Fenton integrated process, the production of H 2 O 2 which is the key reactant of fenton-reaction was driven by the electrons harvested from the exoelectrogens and salinity-gradient between sea water and fresh water in MREC. Complete decolorization and mineralization of 400mgL -1 Orange G was achieved with apparent first order rate constants of 1.15±0.06 and 0.26±0.03h -1 , respectively. Furthermore, the initial concentration of orange G, initial solution pH, catholyte concentration, high and low concentration salt water flow rate and air flow rate were all found to significantly affect the dye degradation. This study provides an efficient and cost-effective system for the degradation of non-biodegradable pollutants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biosorption of Acid Black 172 and Congo Red from aqueous solution by nonviable Penicillium YW 01: kinetic study, equilibrium isotherm and artificial neural network modeling.

PubMed

Yang, Yuyi; Wang, Guan; Wang, Bing; Li, Zeli; Jia, Xiaoming; Zhou, Qifa; Zhao, Yuhua

2011-01-01

The main objective of this work was to investigate the biosorption performance of nonviable Penicillium YW 01 biomass for removal of Acid Black 172 metal-complex dye (AB) and Congo Red (CR) in solutions. Maximum biosorption capacities of 225.38 and 411.53 mg g(-1) under initial dye concentration of 800 mg L(-1), pH 3.0 and 40 °C conditions were observed for AB and CR, respectively. Biosorption data were successfully described with Langmuir isotherm and the pseudo-second-order kinetic model. The Weber-Morris model analysis indicated that intraparticle diffusion was the limiting step for biosorption of AB and CR onto biosorbent. Analysis based on the artificial neural network and genetic algorithms hybrid model indicated that initial dye concentration and temperature appeared to be the most influential parameters for biosorption process of AB and CR onto biosorbent, respectively. Characterization of the biosorbent and possible dye-biosorbent interaction were confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy. Copyright © 2010 Elsevier Ltd. All rights reserved.

Kinetics, isothermal and thermodynamics studies of electrocoagulation removal of basic dye rhodamine B from aqueous solution using steel electrodes

NASA Astrophysics Data System (ADS)

Adeogun, Abideen Idowu; Balakrishnan, Ramesh Babu

2017-07-01

Electrocoagulation was used for the removal of basic dye rhodamine B from aqueous solution, and the process was carried out in a batch electrochemical cell with steel electrodes in monopolar connection. The effects of some important parameters such as current density, pH, temperature and initial dye concentration, on the process, were investigated. Equilibrium was attained after 10 min at 30 °C. Pseudo-first-order, pseudo-second-order, Elovich and Avrami kinetic models were used to test the experimental data in order to elucidate the kinetic adsorption process; pseudo-first-order and Avrami models best fitted the data. Experimental data were analysed using six model equations: Langmuir, Freudlinch, Redlich-Peterson, Temkin, Dubinin-Radushkevich and Sips isotherms and it was found that the data fitted well with Sips isotherm model. The study showed that the process depends on current density, temperature, pH and initial dye concentration. The calculated thermodynamics parameters (Δ G°, Δ H° and Δ S°) indicated that the process is spontaneous and endothermic in nature.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Study of relaxation times of polymethine dyes used for passive mode locking of solid-state lasers emitting between 750 and 850 nm

NASA Astrophysics Data System (ADS)

Grigonis, R.; Derevyanko, Nadezhda A.; Ishchenko, Aleksandr A.; Sirutkaitis, V. A.

2001-11-01

The relaxation times τ of the bleached states of polymethine dyes absorbing light in the 750 — 850-nm are determined by the direct pump — probe method. The effect of the dye structure and the solvent type on the relaxation time is discussed. The role of different intra- and intermolecular interactions in the relaxation of excited electronic states of the dyes is analysed. Polymethine dyes are found (with τ=11 — 75 ps) that are promising for passive mode locking in Cr3+:LiCaAlF6, Cr3+:KZnF3, and Cr3+:LiSrAlF6 crystal lasers.

Study of the sonophotocatalytic degradation of basic blue 9 industrial textile dye over slurry titanium dioxide and influencing factors.

PubMed

González, Antonia Sandoval; Martínez, Susana Silva

2008-09-01

The sonophotocatalytic degradation of basic blue 9 industrial textile dye has been studied in the presence of ultrasound (20 kHz) over a TiO(2) slurry employing an UV lamp (15 W, 352 nm). It was observed that the color removal efficiency was influenced by the pH of the solution, initial dye concentration and TiO(2) amount. It was found that the dye degradation followed apparent first order kinetics. The rate constant increased by decreasing dye concentration and was affected by the pH of the solution with the highest degradation obtained at pH 7. The first order rate constants obtained with sonophotocatalysis were twofold and tenfold than those obtained under photocatalysis and sonolysis, respectively. The chemical oxygen demand was abated over 80%.

Trapping characteristic of halloysite lumen for methyl orange

NASA Astrophysics Data System (ADS)

Chen, Hao; Yan, Hua; Pei, Zhenzhao; Wu, Junyong; Li, Rongrong; Jin, Yanxian; Zhao, Jie

2015-08-01

The interaction of clay minerals and dyes is an area of great interest especially in the development of novel adsorbents. In this report, we demonstrated interaction of halloysite nanotubes (HNTs) and an anionic dye, methyl orange (MO), through a electrostatic attraction. Halloysite lumen has a trapping characteristic for methyl orange, which is mainly determined by the positively charged nature of the inner surface of HNTs. XRD results confirmed that intercalation of methyl orange into HNTs did not occur. SEM-EDS and photostability results showed that MO molecules were primarily in HNTs lumen. Adsorption isotherm studies revealed an interesting phenomenon, i.e., a sudden increase of adsorption capacity occurred in the initial dye concentration of about 75 mg/L, which was just the dye concentration corresponding to the onset of dye oligomer formation. This suggested dye aggregation state had a decisive influence to the adsorption behavior of MO on the halloysite. BET results demonstrated at low and high dye concentrations, single MO molecule and aggregation of several dimers through hydrophobic interaction, interacted with Al-OH2+ sites on the inner wall, respectively. Desorption experiments showed that MO in HNTs can be completely removed with deionized water, indicating halloysite is a low-cost and efficient adsorbent for anionic dye.

Bioremoval of the azo dye Congo Red by the microalga Chlorella vulgaris.

PubMed

Hernández-Zamora, Miriam; Cristiani-Urbina, Eliseo; Martínez-Jerónimo, Fernando; Perales-Vela, Hugo Virgilio; Ponce-Noyola, Teresa; Montes-Horcasitas, María del Carmen; Cañizares-Villanueva, Rosa Olivia

2015-07-01

Discharge of dye-containing wastewater by the textile industry can adversely affect aquatic ecosystems and human health. Bioremoval is an alternative to industrial processes for detoxifying water contaminated with dyes. In this work, active and inactive biomass of the microalga Chlorella vulgaris was assayed for the ability to remove Congo Red (CR) dye from aqueous solutions. Through biosorption and biodegradation processes, Chlorella vulgaris was able to remove 83 and 58 % of dye at concentrations of 5 and 25 mg L(-1), respectively. The maximum adsorption capacity at equilibrium was 200 mg g(-1). The Langmuir model best described the experimental equilibrium data. The acute toxicity test (48 h) with two species of cladocerans indicated that the toxicity of the dye in the effluent was significantly decreased compared to the initial concentrations in the influent. Daphnia magna was the species less sensitive to dye (EC50 = 17.0 mg L(-1)), followed by Ceriodaphnia dubia (EC50 = 3.32 mg L(-1)). These results show that Chlorella vulgaris significantly reduced the dye concentration and toxicity. Therefore, this method may be a viable option for the treatment of this type of effluent.

Homogenous and heterogenous advanced oxidation of two commercial reactive dyes.

PubMed

Balcioglu, I A; Arslan, I; Sacan, M T

2001-07-01

Two commercial reactive dyes, the azo dye Reactive Black 5 and the copper phythalocyanine dye Reactive Blue 21, have been treated at a concentration of 75 mg l(-1) by titanium dioxide mediated photocatalytic (TiO2/UV), dark and UV-light assisted Fenton (Fe2+/H2O2) and Fenton-like (Fe3+/H2O2) processes in acidic medium. For the treatment of Reactive Black 5, all investigated advanced oxidation processes were quite effective in terms of colour, COD as well as TOC removal. Moreover, the relative growth inhibition of the azo dye towards the marine algae Dunaliella tertiolecta that was initially 70%, did not exhibit an increase during the studied advanced oxidation reactions and complete detoxification at the end of the treatment period could be achieved for all investigated treatment processes. However, for Reactive Blue 21, abatement in COD and UV-VIS absorbance values was mainly due to the adsorption of the dye on the photocatalyst surface and/or the coagulative effect of Fe3+/Fe2+ ions. Although only a limited fraction of the copper phythalocyanine dye underwent oxidative degradation, 47% of the total copper in the dye was already released after 1 h photocatalytic treatment.

Mechanism of Cyclic Dye Regeneration During Eosin-Sensitized Photoinitiation in the Presence of Polymerization Inhibitors

PubMed Central

Avens, Heather J.; Bowman, Christopher N.

2009-01-01

A visible light photoinitiator, eosin, in combination with a tertiary amine coinitiator is found to initiate polymerization despite the presence of at least 1000-fold excess dissolved oxygen which functions as an inhibitor of radical polymerizations. Additionally, 0.4 µM eosin is able to overcome 100-fold excess (40 µM) 2,2,6,6-Tetramethyl-1-piperidinyloxy (TEMPO) inhibitor, initiating polymerization after only a 2 minute inhibition period. In contrast, 40 µM Irgacure-2959, a standard cleavage-type initiator, is unable to overcome even an equivalent amount of inhibitor (40 µM TEMPO). Through additional comparisons of these two initiation systems, a reaction mechanism is developed which is consistent with the kinetic data and provides an explanation for eosin’s relative insensitivity to oxygen, TEMPO and other inhibitors. A cyclic mechanism is proposed in which semi-reduced eosin radicals react by disproportionation with radical inhibitors and radical intermediates in the inhibition process to regenerate eosin and effectively consume inhibitor. In behavior similar to that of eosin, rose bengal, fluorescein, and riboflavin are also found to initiate polymerization despite the presence of excess TEMPO, indicating that cyclic regeneration likely enhances the photoinitiation kinetics of many dye photosensitizers. Selection of such dye initiation systems constitutes a valuable strategy for alleviating inhibitory effects in radical polymerizations. PMID:20098667

Time-Delayed Two-Step Selective Laser Photodamage of Dye-Biomolecule Complexes

NASA Astrophysics Data System (ADS)

Andreoni, A.; Cubeddu, R.; de Silvestri, S.; Laporta, P.; Svelto, O.

1980-08-01

A scheme is proposed for laser-selective photodamage of biological molecules, based on time-delayed two-step photoionization of a dye molecule bound to the biomolecule. The validity of the scheme is experimentally demonstrated in the case of the dye Proflavine, bound to synthetic polynucleotides.

Comparative Study on Synergetic Degradation of a Reactive Dye Using Different Types of Fly Ash in Combined Adsorption and Photocatalysis

NASA Astrophysics Data System (ADS)

Giri Babu, P. V. S.; Swaminathan, G.

2016-09-01

A comprehensive study was carried out on four different fly ashes used as a catalyst for the degradation of Acid Red 1 using ultraviolet rays. These fly ashes are collected from different thermal power stations located at various places in India and having different chemical compositions. Three fly ashes are from lignite-based thermal power plants, and one is from the coal-based power plant. One fly ash is classified as Class F, two fly ashes are classified as Class C and remaining one is not conforming to ASTM C618 classification. X-Ray Fluorescence analysis was used to identify the chemical composition of fly ashes and SiO2, Al2O3, CaO, Fe2O3 and TiO2 were found to be the major elements present in different proportions. Various analysis were carried out on all the fly ashes like Scanning Electron Microscopy to identify the microphysical properties, Energy Dispersive X-Ray spectroscopy to quantify the elements present in the catalyst and X-Ray Diffraction to identify the catalyst phase analysis. The radical generated during the reaction was identified by Electron paramagnetic resonance spectroscopy. The parameters such as initial pH of the dye solution, catalyst dosage and initial dye concentration which influence the dye degradation efficiency were studied and optimised. In 60 min duration, the dye degradation efficiency at optimum parametric values of pH 2.5, initial dye concentration of 10 mg/L and catalyst dosage of 1.0 g/L using various fly ashes, i.e., Salam Power Plant, Barmer Lignite Power Plant, Kutch Lignite Power Plant and Neyveli Lignite Thermal Power plant (NLTP) were found to be 40, 60, 67 and 95 % respectively. The contribution of adsorption alone was 18 % at the above mentioned optimum parametric values. Among the above four fly ash NLTP fly ashes proved to be most efficient.

R software package based statistical optimization of process components to simultaneously enhance the bacterial growth, laccase production and textile dye decolorization with cytotoxicity study

PubMed Central

Dudhagara, Pravin; Tank, Shantilal

2018-01-01

The thermophilic bacterium, Bacillus licheniformis U1 is used for the optimization of bacterial growth (R1), laccase production (R2) and synthetic disperse blue DBR textile dye decolorization (R3) in the present study. Preliminary optimization has been performed by one variable at time (OVAT) approach using four media components viz., dye concentration, copper sulphate concentration, pH, and inoculum size. Based on OVAT result further statistical optimization of R1, R2 and R3 performed by Box–Behnken design (BBD) using response surface methodology (RSM) in R software with R Commander package. The total 29 experimental runs conducted in the experimental design study towards the construction of a quadratic model. The model indicated that dye concentration 110 ppm, copper sulphate 0.2 mM, pH 7.5 and inoculum size 6% v/v were found to be optimum to maximize the laccase production and bacterial growth. Whereas, maximum dye decolorization achieved in media containing dye concentration 110 ppm, copper sulphate 0.6 mM, pH 6 and inoculum size 6% v/v. R package predicted R2 of R1, R2 and R3 were 0.9917, 0.9831 and 0.9703 respectively; likened to Design-Expert (Stat-Ease) (DOE) predicted R2 of R1, R2, and R3 were 0.9893, 0.9822 and 0.8442 respectively. The values obtained by R software were more precise, reliable and reproducible, compared to the DOE model. The laccase production was 1.80 fold increased, and 2.24 fold enhancement in dye decolorization was achieved using optimized medium than initial experiments. Moreover, the laccase-treated sample demonstrated the less cytotoxic effect on L132 and MCF-7 cell lines compared to untreated sample using MTT assay. Higher cell viability and lower cytotoxicity observed in a laccase-treated sample suggest the impending application of bacterial laccase in the reduction of toxicity of dye to design rapid biodegradation process. PMID:29718934

Spectral-Polarization Properties and Light Resistance of Polyvinyl-Alcohol Films Colored With Disazo Dyes

NASA Astrophysics Data System (ADS)

Fillipovich, L. N.; Ariko, N. G.; Agabekov, V. E.; Malashko, P. M.

2005-09-01

Polarizers containing disazo dyes from the group of azobenzene-azonaphthalene have been developed. It has been established that their polarizing ability is determined by the mutual disposition of the azo group and electron-donor substituents in the naphthalene ring. On diazo coupling of γ acid into the α position relative to the oxy group, the M1 and M3 dyes are formed, the polarizing ability of which in uniaxially oriented polyvinyl-alcohol films is higher than in the M2 dye produced as a result of diazo coupling into the α position relative to the amino group. On irradiation by UV light, the dyes are subjected to photodestruction, which, in the case of M2, proceeds through trans-cis-isomerization. The rate of photodestruction depends on the aggregation of the dye molecules, and it increases in the presence of a free-radical initiator. The UV absorber (substituted benzotriazole) and the uniaxial orientation of the film retard this process.

Dye removal from textile industrial effluents by adsorption on exfoliated graphite nanoplatelets: kinetic and equilibrium studies.

PubMed

Carvallho, Marilda N; da Silva, Karolyne S; Sales, Deivson C S; Freire, Eleonora M P L; Sobrinho, Maurício A M; Ghislandi, Marcos G

2016-01-01

The concept of physical adsorption was applied for the removal of direct and reactive blue textile dyes from industrial effluents. Commercial graphite nanoplatelets were used as substrate, and the quality of the material was characterized by atomic force and transmission electron microscopies. Dye/graphite nanoplatelets water solutions were prepared varying their pH and initial dye concentration. Exceptionally high values (beyond 100 mg/L) for adsorptive capacity of graphite nanoplatelets could be achieved without complicated chemical modifications, and equilibrium and kinetic experiments were performed. Our findings were compared with the state of the art, and compared with theoretical models. Agreement between them was satisfactory, and allowed us to propose novel considerations describing the interactions of the dyes and the graphene planar structure. The work highlights the important role of these interactions, which can govern the mobility of the dye molecules and the amount of layers that can be stacked on the graphite nanoplatelets surface.

An examination of short-term variations in water quality at a karst spring in Kentucky

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, M.; Meiman, J.

1996-01-01

Water quality at many karst springs undergoes very high amplitude but relatively brief degradation following influxes of runoff. Accurately recording transient variations requires more rigorous sampling strategies than traditional methods. A pilot study to determine the usefulness of high-frequency, flow-dependent sampling strategies, combined with coincidental quantitative dye tracer tests, was implemented in the Big Spring Ground-Water Basin in Mammoth Cave National Park, Kentucky. Data recorded following two separate runoff events showed that the concentrations of two nonpoint source pollutants, fecal coliform bacteria and suspended sediment, greatly exceeded prerunoff event values for very short periods of time. A phreatic conduit segment,more » calculated at 17 million liters in volume, instantaneously propagated head changes, caused by direct runoff entering the aquifer, from the ground-water inputs to Big Spring. A significant delay between the initial increases in discharge and the arrival of direct runoff, as indicated by a steady decrease in specific conductance, represented the time required to displace this volume of phreatic water. The delay showed that sampling a karst spring only during peak discharge would be an unreliable sampling method. Runoff from two different subcatchments was tagged with tracer dye and the timing of the passage of the resultant dye clouds through Big Spring were compared to water quality variations. Distinct lag times between the arrival of direct runoff at Big Spring and the bacteria and suspended sediment waveforms were shown through the concurrent quantitative tracer tests to be related to the areal distribution of land-cover type within the basin.« less

Benchtop Detection of Proteins

NASA Technical Reports Server (NTRS)

Scardelletti, Maximilian C.; Varaljay, Vanessa

2007-01-01

A process, and a benchtop-scale apparatus for implementing the process, have been developed to detect proteins associated with specific microbes in water. The process and apparatus may also be useful for detection of proteins in other, more complex liquids. There may be numerous potential applications, including monitoring lakes and streams for contamination, testing of blood and other bodily fluids in medical laboratories, and testing for microbial contamination of liquids in restaurants and industrial food-processing facilities. A sample can be prepared and analyzed by use of this process and apparatus within minutes, whereas an equivalent analysis performed by use of other processes and equipment can often take hours to days. The process begins with the conjugation of near-infrared-fluorescent dyes to antibodies that are specific to a particular protein. Initially, the research has focused on using near-infrared dyes to detect antigens or associated proteins in solution, which has proven successful vs. microbial cells, and streamlining the technique in use for surface protein detection on microbes would theoretically render similar results. However, it is noted that additional work is needed to transition protein-based techniques to microbial cell detection. Consequently, multiple such dye/antibody pairs could be prepared to enable detection of multiple selected microbial species, using a different dye for each species. When excited by near-infrared light of a suitable wavelength, each dye fluoresces at a unique longer wavelength that differs from those of the other dyes, enabling discrimination among the various species. In initial tests, the dye/antibody pairs are mixed into a solution suspected of containing the selected proteins, causing the binding of the dye/antibody pairs to such suspect proteins that may be present. The solution is then run through a microcentrifuge that includes a membrane that acts as a filter in that it retains the dye/antibody/protein complexes while allowing any remaining unbound dye/antibody pairs to flow away. The retained dye/antibody/protein complexes are transferred to a cuvette, wherein they are irradiated with light from a miniature near-infrared laser delivered via a fiber-optic cable. The resulting fluorescence from the dye(s) is measured by use of a miniature spectrometer, the output of which is digitized, then analyzed by laptop computer. The software running in the computer identifies the protein species by the wavelengths of their spectral peaks and determines the amounts of the proteins, and thus, one day, microbes of the various species from the intensities of the peaks. The abovementioned removal of the unbound dye/antibody pairs during centrifugation prevents false positive readings. The process proves successful in detecting proteins in solution and thus can now be employed for use in microbe detection.

Fast photocatalytic degradation of methylene blue dye using a low-power diode laser.

PubMed

Liu, Xianhua; Yang, Yulou; Shi, Xiaoxuan; Li, Kexun

2015-01-01

This study focused on the application of diode lasers as alternative light sources for the fast photocatalytic degradation of methylene blue. The photocatalytic decomposition of methylene blue in aqueous solution under 443 nm laser light irradiation was found to be technically feasible using Ag/AgCl nanoparticles as photocatalysts. The effects of various experimental parameters, such as irradiation time, light source, catalyst loading, initial dye concentration, pH, and laser energy on decolorization and degradation were investigated. The mineralization of methylene blue was confirmed by chemical oxygen demand analysis. The results demonstrate that the laser-induced photocatalytic process can effectively degrade methylene blue under the optimum conditions (pH 9.63, 4 mg/L MB concentration, and 1.4 g/L Ag/AgCl nanoparticles). Copyright © 2014 Elsevier B.V. All rights reserved.

Optical and Photovoltaic Properties of Thieno[3,2-b]thiophene-Based Push-Pull Organic Dyes with Different Anchoring Groups for Dye-Sensitized Solar Cells.

PubMed

Fernandes, Sara S M; Castro, M Cidália R; Pereira, Ana Isabel; Mendes, Adélio; Serpa, Carlos; Pina, João; Justino, Licínia L G; Burrows, Hugh D; Raposo, M Manuela M

2017-12-31

The effect of anchoring groups on the optical and electrochemical properties of triphenylamine-thienothiophenes, and on the photovoltaic performance of DSSCs photosensitized with the prepared dyes, was studied using newly synthesized compounds with cyanoacetic acid or rhodanine-3-acetic acid groups. Precursor aldehydes were synthesized through Suzuki cross-coupling, whereas Knoevenagel condensation of these with 2-cyanoacetic acid or rhodanine-3-acetic acid afforded the final push-pull dyes. A comprehensive photophysical study was performed in solution and in the solid state. The femtosecond time-resolved transient absorption spectra for the synthesized dyes were obtained following photoexcitation in solution and for the dyes adsorbed to TiO 2 mesoporous films. Information on conformation, electronic structure, and electron distribution was obtained by density functional theory (DFT) and time-dependent DFT calculations. Triphenylamine-thienothiophene functionalized with a cyanoacetic acid anchoring group displayed the highest conversion efficiency (3.68%) as the dye sensitizer in nanocrystalline TiO 2 solar cells. Coadsorption studies were performed for this dye with the ruthenium-based N719 dye, and they showed dye power conversion efficiencies enhanced by 20-64%. The best cell performance obtained with the coadsorbed N719 and cyanoacetic dye showed an efficiency of 6.05%.

Optical and Photovoltaic Properties of Thieno[3,2-b]thiophene-Based Push–Pull Organic Dyes with Different Anchoring Groups for Dye-Sensitized Solar Cells

PubMed Central

2017-01-01

The effect of anchoring groups on the optical and electrochemical properties of triphenylamine-thienothiophenes, and on the photovoltaic performance of DSSCs photosensitized with the prepared dyes, was studied using newly synthesized compounds with cyanoacetic acid or rhodanine-3-acetic acid groups. Precursor aldehydes were synthesized through Suzuki cross-coupling, whereas Knoevenagel condensation of these with 2-cyanoacetic acid or rhodanine-3-acetic acid afforded the final push–pull dyes. A comprehensive photophysical study was performed in solution and in the solid state. The femtosecond time-resolved transient absorption spectra for the synthesized dyes were obtained following photoexcitation in solution and for the dyes adsorbed to TiO2 mesoporous films. Information on conformation, electronic structure, and electron distribution was obtained by density functional theory (DFT) and time-dependent DFT calculations. Triphenylamine–thienothiophene functionalized with a cyanoacetic acid anchoring group displayed the highest conversion efficiency (3.68%) as the dye sensitizer in nanocrystalline TiO2 solar cells. Coadsorption studies were performed for this dye with the ruthenium-based N719 dye, and they showed dye power conversion efficiencies enhanced by 20–64%. The best cell performance obtained with the coadsorbed N719 and cyanoacetic dye showed an efficiency of 6.05%. PMID:29302638

Rapid and high-performance adsorptive removal of hazardous acridine orange from aqueous environment using Abelmoschus esculentus seed powder: Single- and multi-parameter optimization studies.

PubMed

Nayak, Ashish Kumar; Pal, Anjali

2018-07-01

In this research, the performance of naturally abundant lignocellulosic by-product, Abelmoschus esculentus, and its processed seed powder referred as AESP, as a potential biosorbent for the removal of acridine orange (AO) from the aqueous environment was examined. The AESP biosorbent was characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) analysis, diffuse reflectance spectroscopy (DRS), Fourier transform infrared (FTIR) and pH ZPC analyses. The average size of the biosorbent according to particle size distribution analysis was found to be ∼132 μm. The batch adsorption experiments were conducted by altering the parameters such as contact time, solution pH, biosorbent dosage, initial dye concentration, stirring speed and temperature. Sorption of cationic AO dye onto AESP was found to be rapid, and the equilibrium condition reached within 30 min. The isotherms (Langmuir, Freundlich, Redlich-Peterson and Sips), kinetic models (pseudo-first order, pseudo-second order, Elovich, intra-particle diffusion, Bangham and modified-Freundlich models) and thermodynamic parameters were also evaluated. High values of determination coefficients (R 2 ) and minimal values of non-linear error functions (i.e. HYBRD, RMSE, MPSD, ARE, APE and χ 2 ) indicated that experimental data were best fitted with Sips isotherm and pseudo-second order kinetic model. Accordingly, the maximum loading capacity of AESP was found to be 259.4, 284.3 and 346.5 mg/g for the temperatures of 15, 30 and 45 °C, respectively. The thermodynamic parameters showed that the adsorption of AO onto the AESP surface was an endothermic and spontaneous process. Besides these, the central composite experimental design (CCD) superimposed with response surface methodology (RSM) modeling was also employed to investigate the effect of four significant parameters (solution pH, contact time, initial AO concentration and AESP dosage) and their interaction-term effects on the adsorption capacity of AESP and to formulate the mathematical model for the experimental data using multi-variate statistical analysis. Maximum dye uptake capacity under the optimum conditions of variables (pH 8.96, contact time 32.06 min, initial dye concentration 867.71 mg/L and AESP dosage 1.89 g/L) was 312.1 mg/g at temperature 30 °C, and it was found to be very close to the experimentally determined values (313.4 ± 0.057 mg/g). The promising reusability potential of AESP using 0.1 M HCl, implied that, the lignocellulosic biosorbent AESP might be helpful for the appropriate designing of the environmental-friendly purification systems. Copyright © 2018 Elsevier Ltd. All rights reserved.

Validating continuous digital light processing (cDLP) additive manufacturing accuracy and tissue engineering utility of a dye-initiator package.

PubMed

Wallace, Jonathan; Wang, Martha O; Thompson, Paul; Busso, Mallory; Belle, Vaijayantee; Mammoser, Nicole; Kim, Kyobum; Fisher, John P; Siblani, Ali; Xu, Yueshuo; Welter, Jean F; Lennon, Donald P; Sun, Jiayang; Caplan, Arnold I; Dean, David

2014-03-01

This study tested the accuracy of tissue engineering scaffold rendering via the continuous digital light processing (cDLP) light-based additive manufacturing technology. High accuracy (i.e., <50 µm) allows the designed performance of features relevant to three scale spaces: cell-scaffold, scaffold-tissue, and tissue-organ interactions. The biodegradable polymer poly (propylene fumarate) was used to render highly accurate scaffolds through the use of a dye-initiator package, TiO2 and bis (2,4,6-trimethylbenzoyl)phenylphosphine oxide. This dye-initiator package facilitates high accuracy in the Z dimension. Linear, round, and right-angle features were measured to gauge accuracy. Most features showed accuracies between 5.4-15% of the design. However, one feature, an 800 µm diameter circular pore, exhibited a 35.7% average reduction of patency. Light scattered in the x, y directions by the dye may have reduced this feature's accuracy. Our new fine-grained understanding of accuracy could be used to make further improvements by including corrections in the scaffold design software. Successful cell attachment occurred with both canine and human mesenchymal stem cells (MSCs). Highly accurate cDLP scaffold rendering is critical to the design of scaffolds that both guide bone regeneration and that fully resorb. Scaffold resorption must occur for regenerated bone to be remodeled and, thereby, achieve optimal strength.

Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles

PubMed Central

Dhananasekaran, Solairaj; Palanivel, Rameshthangam; Pappu, Srinivasan

2015-01-01

Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB), Bromophenol Blue (BPB) and Coomassie Brilliant Blue (CBB)) by α-chitin nanoparticles (CNP) prepared from Penaeus monodon (Fabricius, 1798) shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR) spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R2 values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes) and pseudo second order kinetics (R2 values were 0.996, 0.999 and 0.996 for MB, BPB and CBB) more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents. PMID:26843977

Adsorptive removal of malachite green from aqueous solutions by almond gum: Kinetic study and equilibrium isotherms.

PubMed

Bouaziz, Fatma; Koubaa, Mohamed; Kallel, Fatma; Ghorbel, Rhoudha Ellouz; Chaabouni, Semia Ellouz

2017-12-01

This work aimed at investigating the potential of almond gum as low cost adsorbent for the removal of the cationic dye; malachite green from aqueous solutions. Almond gum was first analyzed by scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR), and then the adsorption behavior was studied in batch system. The effects of the adsorption parameters (adsorbent dose, pH, contact time, particle size, initial dye concentration, temperature and agitation) on the dye removal have been studied. Adsorption equilibrium and isotherms were evaluated depending on temperature using the isotherms of Freundlich, Langmuir, and Tempkin. The obtained result showed that both Langmuir and Freundlich models were adapted to study the dye sorption. The maximum adsorption capacities were equal to 172.41mg/g, 181.81mg/g, and 196.07mg/g at 303.16K, 313.16K, and 323.16K, respectively. The kinetics of sorption were following the pseudo-second order model. The thermodynamic changes in enthalpy (ΔH), entropy (ΔS), and free energy (ΔG) indicated that the adsorption of malachite green at the surface of almond gum is endothermic and occurs spontaneously. Desorption experiments were conducted to regenerate almond gum, showing great desorption capacity when using HCl at pH 2. Copyright © 2017 Elsevier B.V. All rights reserved.

Charge transfer at organic-inorganic interfaces—Indoline layers on semiconductor substrates

NASA Astrophysics Data System (ADS)

Meyenburg, I.; Falgenhauer, J.; Rosemann, N. W.; Chatterjee, S.; Schlettwein, D.; Heimbrodt, W.

2016-12-01

We studied the electron transfer from excitons in adsorbed indoline dye layers across the organic-inorganic interface. The hybrids consist of indoline derivatives on the one hand and different inorganic substrates (TiO2, ZnO, SiO2(0001), fused silica) on the other. We reveal the electron transfer times from excitons in dye layers to the organic-inorganic interface by analyzing the photoluminescence transients of the dye layers after femtosecond excitation and applying kinetic model calculations. A correlation between the transfer times and four parameters have been found: (i) the number of anchoring groups, (ii) the distance between the dye and the organic-inorganic interface, which was varied by the alkyl-chain lengths between the carboxylate anchoring group and the dye, (iii) the thickness of the adsorbed dye layer, and (iv) the level alignment between the excited dye ( π* -level) and the conduction band minimum of the inorganic semiconductor.

A rapid method for measuring intracellular pH using BCECF-AM.

PubMed

Ozkan, Pinar; Mutharasan, Raj

2002-08-15

A rapid intracellular pH (pH(i)) measurement method based on initial rate of increase of fluorescence ratio of 2',7'-bis(2-carboxyethyl)-5,6-carboxyfluorescein upon dye addition to a cell suspension in growth medium is reported. A dye transport model that describes dye concentration and fluorescence values in intracellular and extracellular spaces provides the mathematical basis for the approach. Experimental results of ammonium chloride challenge response of the two suspension cells, Spodoptera frugiperda and Chinese hamster ovary (CHO) cells, successfully compared with results obtained using traditional perfusion method. Since the cell suspension does not require any preparation, measurement of pH(i) can be completed in about 1 min minimizing any potential errors due to dye leakage.

Comparative study of UV/TiO2, UV/ZnO and photo-Fenton processes for the organic reactive dye degradation in aqueous solution.

PubMed

Peternel, Igor T; Koprivanac, Natalija; Bozić, Ana M Loncarić; Kusić, Hrvoje M

2007-09-05

In this study advanced oxidation processes (AOPs), UV/TiO(2), UV/ZnO and photo-Fenton, were applied in order to degrade C.I. Reactive Red 45 (RR45) dye in aqueous solution. The effects of key operating parameters, such as initial pH, catalyst and hydrogen peroxide dosage as well as the effect of initial dye concentration on decolorization and mineralization extents were studied. Primary objective was to determine the optimal conditions for each of the processes. The influence of added zeolite on the process efficiency was also studied. UV/vis spectrophotometric and total organic carbon (TOC) measurements were performed for determination of decolorization and mineralization extents. It has been found that photo-Fenton process was the most efficient with 74.2% TOC removal and complete color removal achieved after a 1h treatment.

Comparison of ultrasonic with stirrer performance for removal of sunset yellow (SY) by activated carbon prepared from wood of orange tree: artificial neural network modeling.

PubMed

Ghaedi, A M; Ghaedi, M; Karami, P

2015-03-05

The present work focused on the removal of sunset yellow (SY) dye from aqueous solution by ultrasound-assisted adsorption and stirrer by activated carbon prepared from wood of an orange tree. Also, the artificial neural network (ANN) model was used for predicting removal (%) of SY dye based on experimental data. In this study a green approach was described for the synthesis of activated carbon prepared from wood of an orange tree and usability of it for the removal of sunset yellow. This material was characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The impact of variables, including initial dye concentration (mg/L), pH, adsorbent dosage (g), sonication time (min) and temperature (°C) on SY removal were studied. Fitting the experimental equilibrium data of different isotherm models such as Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models display the suitability and applicability of the Langmuir model. Analysis of experimental adsorption data by different kinetic models including pseudo-first and second order, Elovich and intraparticle diffusion models indicate the applicability of the second-order equation model. The adsorbent (0.5g) is applicable for successful removal of SY (>98%) in short time (10min) under ultrasound condition. Copyright © 2014 Elsevier B.V. All rights reserved.

Fluorescence of acridinic dyes in anionic surfactant solution

NASA Astrophysics Data System (ADS)

Pereira, Robson Valentim; Gehlen, Marcelo Henrique

2005-10-01

The interaction of the cationic dyes acridine, 9-aminoacridine (9AA), and proflavine, with sodium dodecyl sulfate (SDS) was studied by electronic absorption, steady-state and time-resolved fluorescence spectroscopies. The dyes interact with SDS in the pre-micellar region leading in two cases to dimerization in dye-surfactant aggregates, but with distinct molecular arrangements. For proflavine, the observed red shift of the electronic absorption band indicates the presence of J-aggregate, which are nonfluorescent. In the case of 9AA, the aggregates were characterized as nonspecific (neither J- nor H-type is spectroscopically observed). The time-resolved emission spectra gives evidences of the presence of weakly bound dimers by the recovery of three defined decay times by global analysis: dye monomer ( τ1 = 16.4 ns), dimer ( τ2 = 7.1 ns), and a faster component ( τ3 = 2.1 ns) ascribed to intracluster energy migration between monomer and dimer. Acridine has a weak interaction with SDS forming only an ion pair without further self-aggregation of the dye.

Fluorescence of acridinic dyes in anionic surfactant solution.

PubMed

Pereira, Robson Valentim; Gehlen, Marcelo Henrique

2005-10-01

The interaction of the cationic dyes acridine, 9-aminoacridine (9AA), and proflavine, with sodium dodecyl sulfate (SDS) was studied by electronic absorption, steady-state and time-resolved fluorescence spectroscopies. The dyes interact with SDS in the pre-micellar region leading in two cases to dimerization in dye-surfactant aggregates, but with distinct molecular arrangements. For proflavine, the observed red shift of the electronic absorption band indicates the presence of J-aggregate, which are nonfluorescent. In the case of 9AA, the aggregates were characterized as nonspecific (neither J- nor H-type is spectroscopically observed). The time-resolved emission spectra gives evidences of the presence of weakly bound dimers by the recovery of three defined decay times by global analysis: dye monomer (tau1 = 16.4 ns), dimer (tau2 = 7.1 ns), and a faster component (tau3 = 2.1 ns) ascribed to intracluster energy migration between monomer and dimer. Acridine has a weak interaction with SDS forming only an ion pair without further self-aggregation of the dye.

Rapid and high-capacity ultrasonic assisted adsorption of ternary toxic anionic dyes onto MOF-5-activated carbon: Artificial neural networks, partial least squares, desirability function and isotherm and kinetic study.

PubMed

Askari, Hanieh; Ghaedi, Mehrorang; Dashtian, Kheibar; Azghandi, Mohammad Hossein Ahmadi

2017-07-01

The present paper focused on the ultrasonic assisted simultaneous removal of fast green (FG), eosin Y (EY) and quinine yellow (QY) from aqueous media following using MOF-5 as a metal organic framework and activated carbon hybrid (AC-MOF-5). The structure and morphology of AC-MOF-5 was identified by SEM, FTIR and XRD analysis. The interactive and main effects of variables such as pH, initial dyes concentration (mgL -1 ), adsorbent dosage (mg) and sonication time (min) on removal percentage were studied by central composite design (CCD), subsequent desirability function (DF) permit to achieved real variable experimental condition. Optimized values were found 7.06, 5.68, 7.59 and 5.04mgL -1 , 0.02g and 2.55min for pH, FG, EY and QY concentration, adsorbent dosage and sonication time, respectively. Under this conditions removal percentage were obtained 98.1%, 98.1% and 91.91% for FG, EY and QY, respectively. Two models, namely partial least squares (PLS) and multi-layer artificial neural network (ANN) model were used for building up to construct an empirical model to predict the dyes under study removal behavior. The obtained results show that ANN and PLS model is a powerful tool for prediction of under-study dyes adsorption by AC-MOF-5. The evaluation and estimation of equilibrium data from traditional isotherm models display that the Langmuir model indicated the best fit to the equilibrium data with maximum adsorption capacity of 21.230, 20.242 and 18.621mgg -1 , for FG, EY and QY, respectively, while the adsorption rate efficiently follows the pseudo-second-order model. Copyright © 2016 Elsevier B.V. All rights reserved.

Sulfate-reducing mixed communities with the ability to generate bioelectricity and degrade textile diazo dye in microbial fuel cells.

PubMed

Miran, Waheed; Jang, Jiseon; Nawaz, Mohsin; Shahzad, Asif; Lee, Dae Sung

2018-06-15

The biotreatment of recalcitrant wastes in microbial fuel cells (MFCs) rather than chemical, physical, and advanced oxidation processes is a low-cost and eco-friendly process. In this study, sulfate-reducing mixed communities in MFC anodic chamber were employed for simultaneous electricity generation, dye degradation, and sulfate reduction. A power generation of 258 ± 10 mW/m 2 was achieved under stable operating conditions in the presence of electroactive sulfate-reducing bacteria (SRB). The SRBs dominant anodic chambers result in dye, chemical oxygen demand (COD), and sulfate removal of greater than 85% at an initial COD (as lactate)/SO 4 2- mass ratio of 2.0 and dye concentration of 100 mg/L. The effects of the COD/SO 4 2- ratio (5.0:1.0-0.5:1.0) and initial diazo dye concentration (100-1000 mg/L) were studied to evaluate and optimize the MFC performance. Illumina Miseq technology for bacterial community analysis showed that Proteobacteria (89.4%), Deltaproteobacteria (52.7%), and Desulfovibrio (48.2%) were most dominant at phylum, class, and genus levels, respectively, at the MFC anode. Integration of anaerobic SRB culture in MFC bioanode for recalcitrant chemical removal and bioenergy generation may lead to feasible option than the currently used technologies in terms of overall pollutant treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

Removal of methylene blue from aqueous solution by wood millet carbon optimization using response surface methodology

NASA Astrophysics Data System (ADS)

Ghaedi, Mehrorang; Kokhdan, Syamak Nasiri

2015-02-01

The use of cheep, non-toxic, safe and easily available adsorbent are efficient and recommended material and alternative to the current expensive substance for pollutant removal from wastewater. The activated carbon prepared from wood waste of local tree (millet) extensively was applied for quantitative removal of methylene blue (MB), while simply. It was used to re-used after heating and washing with alkaline solution of ethanol. This new adsorbent was characterized by using BET surface area measurement, FT-IR, pH determination at zero point of charge (pHZPC) and Boehm titration method. Response surface methodology (RSM) by at least the number of experiments main and interaction of experimental conditions such as pH of solution, contact time, initial dye concentration and adsorbent dosage was optimized and set as pH 7, contact time 18 min, initial dye concentration 20 ppm and 0.2 g of adsorbent. It was found that variable such as pH and amount of adsorbent as solely or combination effects seriously affect the removal percentage. The fitting experimental data with conventional models reveal the applicability of isotherm models Langmuir model for their well presentation and description and Kinetic real rate of adsorption at most conditions efficiently can be represented pseudo-second order, and intra-particle diffusion. It novel material is good candidate for removal of huge amount of MB (20 ppm) in short time (18 min) by consumption of small amount (0.2 g).

Decolorization of Mordant red 73 azo dye in water using H2O2/UV and photo-Fenton treatment.

PubMed

Elmorsi, Taha M; Riyad, Yasser M; Mohamed, Zeinhom H; Abd El Bary, Hassan M H

2010-02-15

Decolorization of the Mordant red 73 (MR73) azo dye in water was investigated in laboratory-scale experiments using UV/H(2)O(2) and photo-Fenton treatments. Photodegradation experiments were carried out in a stirred batch photoreactor equipped with a low-pressure mercury lamp as UV source at 254 nm. The effect of operating parameters such as pH, [H(2)O(2)](,) [dye] and the presence of inorganic salts (NaNO(3), NaCl and Na(2)CO(3)) were also investigated. The results indicated that complete dye decolorization was obtained in less than 60 min under optimum conditions. Furthermore, results showed that dye degradation was dependent upon pH, [H(2)O(2)] and initial dye concentration. The presence of chloride ion led to large decreases in the photodegradation rate of MR73 while both nitrate and carbonate ions have a slight effect. The photo-Fenton treatment, in the presence of Fe powder as a source of Fe(2+) ions, was highly efficient and resulted in 99% decolorization of the dye in 15 min. Mineralization of MR73 dye was investigated by determining chemical oxygen demand (COD). In a 3h photoperiod "65%" of the dye was mineralized by the H(2)O(2)/UV process, while the photo-Fenton treatment was more efficient producing 85% mineralization over the same 3-h period.

Bacterial and dye penetration through interim restorations used during endodontic treatment of molar teeth.

PubMed

Chailertvanitkul, Pattama; Abbott, Paul V; Riley, Thomas V; Sooksuntisakoonchai, Namchai

2009-07-01

The purpose of this study was to investigate the association between dye and bacterial penetration through interim restorations used during endodontic treatment. Sixty-four extracted human teeth were used, with 2 teeth each as positive and negative controls. Endodontic access with a mesio-occluso-distal cavity was prepared. Palatal cusps of maxillary molars and buccal cusps of mandibular molars were removed. Cotton was placed over the canals and covered with Cavit. Thirty teeth were restored with Ketac Silver (KS) and 30 with KS reinforced with a stainless steel band (KSSB). Samples were submersed in India ink mixed with brain heart infusion broth containing Streptococcus gordonii. After 3 months of simulated chewing, structural integrity and dye and bacterial penetration were assessed. Positive controls had both dye and bacterial penetration. Negative controls had no dye or bacterial penetration. All KS restorations debonded, whereas 18 KSSB restorations (60%) debonded. KS restorations were 1.67 times more likely to debond than KSSB restorations (Fisher exact test). KS was 1.3 times more likely to have dye penetration than KSSB (Fisher exact test) and 3 times more likely to have bacterial penetration, although not statistically significant (chi(2) test). Overall, 88.3% of specimens had dye penetration, and 20% had bacterial penetration. This 68.3% difference indicated no association between dye and bacterial penetration (exact McNemar test). Stainless steel bands helped maintain structural integrity of KS restorations under masticatory function. Bands helped prevent dye penetration but not bacterial penetration. There was no association between dye and bacterial penetration.

Enzyme-mediated bacterial biodegradation of an azo dye (C.I. Acid blue 113): reuse of treated dye wastewater in post-tanning operations.

PubMed

Senthilvelan, T; Kanagaraj, J; Panda, R C

2014-11-01

"Dyeing" is a common practice used to color the hides during the post-tanning operations in leather processing generating plenty of wastewater. The waste stream containing dye as pollutant is severely harmful to living beings. An azo dye (C.I. Acid Blue 113) has been biodegraded effectively by bacterial culture mediated with azoreductase enzyme to reduce the pollution load in the present investigation. The maximum rate of dye degradation was found to be 96 ± 4 and 92 ± 4 % for the initial concentrations of 100 and 200 mg/l, respectively. The enzyme activity was measured using NADH as a substrate. Fourier transform infrared spectroscopy (FT-IR) analysis was confirmed that the transformation of azo linkage could be transformed into N2 or NH3 or incorporated into complete biomass. Breaking down of dye molecules to various metabolites (such as aniline, naphthalene-1,4-diamine, 3-aminobenzenesulfonic acid, naphthalene-1-sulfonic acid, 8-aminonaphthalene-1-sulfonic acid, 5,8-diaminonaphthalene-1-sulfonic acid) was confirmed by gas chromatography and mass spectra (GC-MS) and mass (electrospray ionization (ESI)) spectra analysis. The treated wastewater could be reused for dyeing operation in the leather processing, and the properties of produced leather were evaluated by conventional methods that revealed to have improved dye penetration into the grain layer of experimental leather sample and resulted in high levelness of dyeing, which helps to obtain the desired smoothness and soft leather properties.

Decolorization of different textile dyes by Penicillium simplicissimum and toxicity evaluation after fungal treatment

PubMed Central

Bergsten-Torralba, L.R.; Nishikawa, M.M.; Baptista, D.F.; Magalhães, D.P.; da Silva, M.

2009-01-01

The objective of this study was to investigate the capacity of decolorization and detoxification of the textile dyes Reactive Red 198 (RR198), Reactive Blue 214 (RB214), Reactive Blue 21 (RB21) and the mixture of the three dyes (MXD) by Penicillium simplicissimum INCQS 40211. The dye RB21, a phthalocyanine, was totally decolorized in 2 days, and the others, the monoazo RR198, the diazo RB214 and MXD were decolorized after 7 days by P. simplicissimum. Initially the dye decolorization involved dye adsorption by the biomass followed by degradation. The acute toxicity after fungal treatment was monitored with the microcrustacean Daphnia pulex and measured through Effective Concentration 50% (EC50). P. simplicissimum reduced efficiently the toxicity of RB21 from moderately acutely toxic to minor acutely toxic and it also reduced the toxicity of RB214 and MXD, which remained minor acutely toxic. Nevertheless, the fungus increased the toxicity of RR198 despite of the reduction of MXD toxicity, which included this dye. Thus, P. simplicissimum INCQS 40211 was efficient to decolorize different textile dyes and the mixture of them with a significant reduction of their toxicity. In addition this investigation also demonstrated the need of toxicological assays associated to decolorization experiments. PMID:24031428

Simultaneous photocatalytic and microbial degradation of dye-containing wastewater by a novel g-C3N4-P25/photosynthetic bacteria composite

PubMed Central

Zhang, Xinying; Wu, Yan; Xiao, Gao; Tang, Zhenping; Wang, Meiyin; Liu, Fuchang; Zhu, Xuefeng

2017-01-01

Azo dyes are very resistant to light-induced fading and biodegradation. Existing advanced oxidative pre-treatment methods based on the generation of non-selective radicals cannot efficiently remove these dyes from wastewater streams, and post-treatment oxidative dye removal is problematic because it may leave many byproducts with unknown toxicity profiles in the outgoing water, or cause expensive complete mineralization. These problems could potentially be overcome by combining photocatalysis and biodegradation. A novel visible-light-responsive hybrid dye removal agent featuring both photocatalysts (g-C3N4-P25) and photosynthetic bacteria encapsulated in calcium alginate beads was prepared by self-assembly. This system achieved a removal efficiency of 94% for the dye reactive brilliant red X-3b and also reduced the COD of synthetic wastewater samples by 84.7%, successfully decolorized synthetic dye-contaminated wastewater and reduced its COD, demonstrating the advantages of combining photocatalysis and biocatalysis for wastewater purification. The composite apparently degrades X-3b by initially converting the dye into aniline and phenol derivatives whose aryl moieties are then attacked by free radicals to form alkyl derivatives, preventing the accumulation of aromatic hydrocarbons that might suppress microbial activity. These alkyl intermediates are finally degraded by the photosynthetic bacteria. PMID:28273118

Role of surfactant derived intermediates in the efficacy and mechanism for radiation chemical degradation of a hydrophobic azo dye, 1-phenylazo-2-naphthol.

PubMed

Das, Laboni; Chatterjee, Suchandra; Naik, Devidas B; Adhikari, Soumyakanti

2015-11-15

A combined methodology involving gamma and pulse radiolysis, product analysis and toxicity studies has been adopted to comprehend the degradation process of a model hydrophobic azo dye, 1-phenylazo-2-naphthol, emphasizing the role of the surfactant, which is an integral part of textile waste. Two new and important findings are underlined in this article. The first is the direct attestation of the hydrazyl radical-parent adduct, formed in the reaction of the dye with e(-)aq followed by protonation and subsequent addition to the unreacted dye molecule. This has been confirmed from concentration dependent studies. Secondly, we have clearly shown that in the reaction of hydroxyl radical with the dye in Triton X-100 media, the initially produced TX radicals cause reductive degradation of the dye. Identification and detailed analysis of HPLC and GCMS data reveals that similar products are formed in both the reactions of e(-)aq and OH radicals. Moreover, the cytotoxicity of 10(-4)moldm(-3) dye was found to be reduced significantly after irradiation. Thus, the present study not only depicts new pathways for the degradation of hydrophobic azo dye, but also demonstrates the role of a surfactant in the entire process. Copyright © 2015 Elsevier B.V. All rights reserved.

Mechanisms and chemistry of dye adsorption on manganese oxides-modified diatomite.

PubMed

Al-Ghouti, Mohammad A; Al-Degs, Yehya S; Khraisheh, Majeda A M; Ahmad, Mohammad N; Allen, Stephen J

2009-08-01

The investigations into structural changes which occur during adsorbent modification and the adsorption mechanisms are essential for an effective design of adsorption systems. Manganese oxides were impregnated onto diatomite to form the type known as delta-birnessite. Initial investigations established the effectiveness of manganese oxides-modified diatomite (MOMD) to remove basic and reactive dyes from aqueous solution. The adsorption capacity of MOMD for methylene blue (MB), hydrolysed reactive black (RB) and hydrolysed reactive yellow (RY) was 320, 419, and 204mg/g, respectively. Various analytical techniques were used to characterise the structure and the mechanisms of the dye adsorption process onto MOMD such as Fourier transform infrared (FTIR), X-ray diffraction (XRD) and atomic absorption spectrometry (A.A.). A small shift to higher values of the d-spacing of dye/MOMD was observed indicating that a small amount of the dye molecules were intercalated in the MOMD structure and other molecules were adsorbed on the external surface of MOMD. Two mechanisms of dye adsorption onto MOMD were proposed; intercalation of the dye in the octahedral layers and adsorption of the dye on the MOMD external surface. Moreover, the results demonstrated that the MOMD structure was changed upon insertion of MB and RY with an obvious decrease in the intensity of the second main peak of the MOMD X-ray pattern.

Theoretical Study of Effect of Introducing π-Conjugation on Efficiency of Dye-Sensitized Solar Cell.

PubMed

Lee, Geon Hyeong; Kim, Young Sik

2018-09-01

In this study, phenoxazine (PXZ)-based dye sensitizers with triphenylamine (TPA) as a dual-electron donor and thiophen and benzothiadiazole (BTD) or 4,7-diethynylbenzo[c][1,2,5]thiadiazole (DEBT) as an electron acceptor (dye1, dye2, and dye3) were designed and investigated. dye3 can significantly stabilize the lowest unoccupied molecular orbital (LUMO) energy level of an organic dye. We used density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations to better understand the factors responsible for the photovoltaic performance. The absorption spectrum of the dyes showed different forms because of the different energy levels of the molecular orbital (MO) of each dye and the intramolecular energy transfer (EnT). Among the three dyes, dye3 showed greater red-shift, broader absorption spectra, and higher molar extinction coefficient. These results indicate that adding a withdrawing unit and π-conjugation to a dye can result in good photovoltaic properties for dye-sensitized solar cells (DSSCs).

Dye and its removal from aqueous solution by adsorption: a review.

PubMed

Yagub, Mustafa T; Sen, Tushar Kanti; Afroze, Sharmeen; Ang, H M

2014-07-01

In this review article the authors presented up to-date development on the application of adsorption in the removal of dyes from aqueous solution. This review article provides extensive literature information about dyes, its classification and toxicity, various treatment methods, and dye adsorption characteristics by various adsorbents. One of the objectives of this review article is to organise the scattered available information on various aspects on a wide range of potentially effective adsorbents in the removal of dyes. Therefore, an extensive list of various adsorbents such as natural materials, waste materials from industry, agricultural by-products, and biomass based activated carbon in the removal of various dyes has been compiled here. Dye bearing waste treatment by adsorption using low cost alternative adsorbent is a demanding area as it has double benefits i.e. water treatment and waste management. Further, activated carbon from biomass has the advantage of offering an effected low cost replacement for non-renewable coal based granular activated carbon provided that they have similar or better adsorption on efficiency. The effectiveness of various adsorbents under different physico-chemical process parameters and their comparative adsorption capacity towards dye adsorption has also been presented. This review paper also includes the affective adsorption factors of dye such as solution pH, initial dye concentration, adsorbent dosage, and temperature. The applicability of various adsorption kinetic models and isotherm models for dye removal by wide range of adsorbents is also reported here. Conclusions have been drawn from the literature reviewed and few suggestions for future research are proposed. Copyright © 2014 Elsevier B.V. All rights reserved.

Pad ultrasonic batch dyeing of causticized lyocell fabric with reactive dyes.

PubMed

Babar, Aijaz Ahmed; Peerzada, Mazhar Hussain; Jhatial, Abdul Khalique; Bughio, Noor-Ul-Ain

2017-01-01

Conventionally, cellulosic fabric dyed with reactive dyes requires significant amount of salt. However, the dyeing of a solvent spun regenerated cellulosic fiber is a critical process. This paper presents the dyeing results of lyocell fabrics dyed with conventional pad batch (CPB) and pad ultrasonic batch (PUB) processes. The dyeing of lyocell fabrics was carried out with two commercial dyes namely Drimarine Blue CL-BR and Ramazol Blue RGB. Dyeing parameters including concentration of sodium hydroxide, sodium carbonate and dwell time were compared for the two processes. The outcomes show that PUB dyed samples offered reasonably higher color yield and dye fixation than CPB dyed samples. A remarkable reduction of 12h in batching time, 18ml/l in NaOH and 05g/l in Na 2 CO 3 quantity was observed for PUB processed samples producing similar results compared to CPB process, making PUB a more economical, productive and an environment friendly process. Color fastness examination witnessed identical results for both PUB and CPB methods. No significant change in surface morphology of PUB processed samples was observed through scanning electron microscope (SEM) analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Biphasic association of T7 RNA polymerase and a nucleotide analogue, cibacron blue as a model to understand the role of initiating nucleotide in the mechanism of enzyme action.

PubMed

Pai, Sudipta; Das, Mili; Banerjee, Rahul; Dasgupta, Dipak

2011-08-01

T7 RNA polymerase (T7 RNAP) is an enzyme that utilizes ribonucleotides to synthesize the nascent RNA chain in a template-dependent manner. Here we have studied the interaction of T7 RNAP with cibacron blue, an anthraquinone monochlorotriazine dye, its effect on the function of the enzyme and the probable mode of binding of the dye. We have used difference absorption spectroscopy and isothermal titration calorimetry to show that the dye binds T7 RNAP in a biphasic manner. The first phase of the binding is characterized by inactivation of the enzyme. The second binding site overlaps with the common substrate-binding site of the enzyme. We have carried out docking experiment to map the binding site of the dye in the promoter bound protein. Competitive displacement of the dye from the high affinity site by labeled GTP and isothermal titration calorimetry of high affinity GTP bound enzyme with the dye suggests a strong correlation between the high affinity dye binding and the high affinity GTP binding in T7 RNAP reported earlier from our laboratory.

Preparation of ZnO Photocatalyst for the Efficient and Rapid Photocatalytic Degradation of Azo Dyes.

PubMed

Chen, Xiaoqing; Wu, Zhansheng; Liu, Dandan; Gao, Zhenzhen

2017-12-01

Zinc oxide (ZnO) photocatalysts were synthesized by sol-gel method using zinc acetate as precursor for degradation of azo dyes under UV irradiation. The resultant samples were characterized by different techniques, such as XRD, SEM, and EDX. The influence of preparation conditions such as calcination temperature and composite ratio on the degradation of methyl orange (MO) was investigated. ZnO prepared with a composite ratio of 4:1 and calcination temperature of 400 °C exhibited 99.70% removal rate for MO. The effect of operation parameters on the degradation was also studied. Results showed that the removal rate of azo dyes increased with the increased dosage of catalyst and decreased initial concentration of azo dyes and the acidic condition is favorable for degradation. Furthermore, the kinetics and scavengers of the reactive species during the degradation were also investigated. It was found that the degradation of azo dyes fitted the first-order kinetics and superoxide ions were the main species. The proposed photocatalyst can efficiently and rapidly degrade azo dyes; thus, this economical and environment-friendly photocatalyst can be applied to the treatment of wastewater contaminated with synthetic dyes.

Influence of styryl dyes on blood erythrocytes

NASA Astrophysics Data System (ADS)

Nizomov, Negmat; Barakaeva, Mubaro; Kurtaliev, Eldar N.; Rahimov, Sherzod I.; Khakimova, Dilorom P.; Khodjayev, Gayrat; Yashchuk, Valeriy N.

2008-08-01

It was studied the influence of F, Sbt, Sil, Sbo monomer and homodimer Dst-5, Dst-10, Dbt-5, Dbt-10, Dil-10, Dbo-10 styryl dyes on blood erythrocytes of white rats. It was shown that the homodimer styryl dyes Dst-5, Dbt-5 and Dbo-10 decrease the erythrocytes quantity by 1.5-2 times more as compared with monomer dyes Sbt and Sbo. The main cause of dyes different action is the different oxidation degree of intracellular hemoglobin evoked by these dyes. It was established that the observed effects was connected with different penetration of these dyes through membrane of erythrocytes and with interaction of these dyes with albumin localized in membranes of cells.

Photo-catalytic decolourisation of toxic dye with N-doped titania: a case study with Acid Blue 25.

PubMed

Chakrabortty, Dhruba; Gupta, Susmita Sen

2013-05-01

Dyes are one of the hazardous water pollutants. Toxic Acid Blue 25, an anthraquinonic dye, has been decolourised by photo-catalysing it with nitrogen doped titania in aqueous medium. The photo catalyst was prepared from 15% TiCl3 and 25% aqueous NH3 solution as precursor. XRD and TEM revealed the formation of well crystalline anatase phase having particle size in the nano-range. BET surface area of the sample was higher than that of pure anatase TiO2. DRS showed higher absorption of radiation in visible range compared to pure anatase TiO2. XPS revealed the presence of nitrogen in N-Ti-O environment. The experimental parameters, namely, photocatalyst dose, initial dye concentration as well as solution pH influence the decolourisation process. At pH 3.0, the N-TiO2 could decolourise almost 100% Acid Blue 25 within one hour. The influence of N-TiO2 dose, initial concentration of Acid Blue 25 and solution pH on adsorption-desorption equilibrium is also studied. The adsorption process follows Lagergren first order kinetics while the modified Langmuir-Hinselwood model is suitably fitted for photocatalytic decolourisation of Acid Blue 25.

Cadmium telluride nanoparticles loaded on activated carbon as adsorbent for removal of sunset yellow

NASA Astrophysics Data System (ADS)

Ghaedi, M.; Hekmati Jah, A.; Khodadoust, S.; Sahraei, R.; Daneshfar, A.; Mihandoost, A.; Purkait, M. K.

2012-05-01

Adsorption is a promising technique for decolorization of effluents of textile dyeing industries but its application is limited due to requirement of high amounts of adsorbent required. The objective of this study was to assess the potential of cadmium telluride nanoparticles loaded onto activated carbon (CdTN-AC) for the removal of sunset yellow (SY) dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdTN-AC dose, and temperature. In order to investigate the efficiency of SY adsorption on CdTN-AC, pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. Thermodynamic parameters such as enthalpy, entropy, activation energy, and sticking probability were also calculated. It was found that the sorption of SY onto CdTN-AC was spontaneous and endothermic in nature. The proposed adsorbent is applicable for SY removal from waste of real effluents including pea-shooter, orange drink and jelly banana with efficiency more than 97%.

Potential of the aquatic fern Azolla filiculoides in biodegradation of an azo dye: modeling of experimental results by artificial neural networks.

PubMed

Khataee, A R; Movafeghi, A; Vafaei, F; Lisar, S Y Salehi; Zarei, M

2013-01-01

The potential of an aquatic fern, Azolla filiculoides, in phytoremediation of a mono azo dye solution, C.I. Acid Blue 92 (AB92), was studied. The effects of operational parameters such as reaction time, initial dye concentration, fern fresh weight, pH, temperature and reusability of the fern on biodegradation efficiency were investigated. The intermediate compounds produced by biodegradation process were analyzed using GC-MS analysis. An artificial neural network (ANN) model was developed to predict the biodegradation efficiency. The findings indicated that ANN provides reasonable predictive performance (R2 = 0.961). The effects of AB92 solutions (10 and 20 mg L(-1)) on growth, chlorophylls and carotenoids content, activity of antioxidant enzymes such as superoxide dismutase, peroxidase and catalase and formation of malondialdehyde were analyzed. AB92 generally showed inhibitory effects on the growth. Moreover, photosynthetic pigments in the fronds significantly decreased in the treatments. An increase was detected for lipid peroxidation and antioxidant enzymes activity, suggesting that AB92 caused reactive oxygen species production in Azolla fronds, which were scavenged by induced activities of antioxidant enzymes.

Photocatalytic detoxification of Acid Red 18 by modified ZnO catalyst under sunlight irradiation

NASA Astrophysics Data System (ADS)

Senthilraja, A.; Subash, B.; Dhatshanamurthi, P.; Swaminathan, M.; Shanthi, M.

2015-03-01

In this work, hybrid structured Bi-Au-ZnO composite was prepared by precipitation-decomposition method. This method is mild, economical and efficient. Bi-Au-ZnO was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectrum (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL) and BET surface area measurements. Photocatalytic activity of Bi-Au-ZnO was evaluated by irradiating the Acid Red 18 (AR 18) dye solution under sun light. Heterostructured Bi-Au-ZnO photocatalyst showed higher photocatalytic activity than those of individual Bi-ZnO, Au-ZnO, bare ZnO, and TiO2-P25 at pH 11. The effects of operational parameters such as the amount of catalyst dosage, dye concentration, initial pH on photo mineralization of AR 18 dye have been analyzed. The mineralization of AR 18 has been confirmed by chemical oxygen demand (COD) measurements. A possible mechanism is proposed for the degradation of AR 18 under sun light. Finally, Bi-Au-ZnO heterojunction photocatalyst was more stable and could be easily recycled several times opening a new avenue for potential industrial applications.

Exploring the dynamics of fluorescence staining of bacteria with cyanine dyes for the development of kinetic assays

NASA Astrophysics Data System (ADS)

Thomas, Marlon Sheldon

Bacterial infections continue to be one of the major health risks in the United States. The common occurrence of such infection is one of the major contributors to the high cost of health care and significant patient mortality. The work presented in this thesis describes spectroscopic studies that will contribute to the development of a fluorescent assay that may allow the rapid identification of bacterial species. Herein, the optical interactions between six bacterial species and a series of thiacyanine dyes are investigated. The interactions between the dyes and the bacterial species are hypothesized to be species-specific. For this thesis, two Gram-negative strains, Escherichia coli (E. coli) TOP10 and Enterobacter aerogenes; two Gram-positive bacterial strains, Bacillus sphaericus and Bacillus subtilis; and two Bacillus endospores, B. globigii and B. thuringiensis, were used to test the proposed hypothesis. A series of three thiacyanine dyes---3,3'-diethylthiacyanine iodide (THIA), 3,3'-diethylthiacarbocyanine iodide (THC) and thiazole orange (THO)---were used as fluorescent probes. The basis of our spectroscopic study was to explore the bacterium-induced interactions of the bacterial cells with the individual thiacyanine dyes or with a mixture of the three dyes. Steady-state absorption spectroscopy revealed that the different bacterial species altered the absorption properties of the dyes. Mixed-dye solutions gave unique absorption patterns for each bacteria tested, with competitive binding observed between the bacteria and spectrophotometric probes (thiacyanine dyes). Emission spectroscopy recorded changes in the emission spectra of THIA following the introduction of bacterial cells. Experimental results revealed that the emission enhancement of the dyes resulted from increases in the emission quantum yield of the thiacyanine dyes upon binding to the bacteria cellular components. The recorded emission enhancement data were fitted to an exponential (mono-exponential or bi-exponential) function, and time constants were extracted by regressing on the experimental data. The addition of the TWEEN surfactants decreased the rate at which the dyes interacted with the bacterial cells, which typically resulted in larger time constants derived from an exponential fit. ANOVA analysis of the time constants confirmed that the values of the time constants clustered in a narrow range and were independent of dye concentration and weakly dependent on cell density.

Fixed-bed column performances of azure-II and auramine-O adsorption by Pinus eldarica stalks activated carbon and its composite with zno nanoparticles: Optimization by response surface methodology based on central composite design.

PubMed

Jafari, Maryam; Rahimi, Mahmood Reza; Ghaedi, Mehrorang; Javadian, Hamedreza; Asfaram, Arash

2017-12-01

A continuous adsorption was used for removal of azure II (AZ II) and auramine O (AO) from aqueous solutions using Pinus eldarica stalks activated carbon (PES-AC) from aqueous solutions. The effects of initial dye concentration, flow rate, bed height and contact time on removal percentage of AO and AZ II were evaluated and optimized by central composite design (CCD) at optimum pH = 7.0. ZnO nanoparticles loaded on activated carbon were also used to remove AO and AZ II at pH = 7.0 and other optimum conditions. The breakthrough curves were obtained at different flow rates, initial dye concentrations and bed heights and the experimental data were fitted by Thomas, Adams-Bohart and Yoon-Nelson models. The main parameters of fixed-bed column including its adsorption capacity at breakthrough point (q b ), adsorption capacity at saturation point (q s ), mass transfer zone (MTZ), total removal percentage (R%), and empty bed contact time (EBCT) were calculated. The removal percentages calculated for AZ II and AO II were in the range of 51.6-61.1% and 40.6-61.6%, respectively. Bed adsorption capacity (N 0 ) and critical bed depth (Z 0 ) were obtained by BDST model. Copyright © 2017 Elsevier Inc. All rights reserved.

Hair dye use and risk of human cancer

PubMed Central

Zhang, Yawei; Kim, Christopher; Zheng, Tongzhang

2016-01-01

Over 50% of the adult population will use hair dyes at some point in their lifetimes. Hair dyes consist of various chemicals and the composition of these chemicals vary by hair dye types. Chemicals p-phenylenediamine and aminophenyl have been suggested as possible carcinogens or mutagens in experimental studies. The scientific community has been interested in this potential public health impact and the results of published epidemiological studies are summarized here. The current evidence provides limited evidences on the association between personal hair dye use and human cancer risk, except for the possibility of hematopoietic cancers and to a lesser extent, bladder cancer. Risk appears to be affected by time period of use and by specific genetic polymorphisms. Future studies should investigate potential gene and environment interaction to assess possible genetic susceptibility. Several methodological issues should also be considered in future studies including completed hair dye use information such as on timing, duration, frequency and type of hair dye product use. PMID:22201892

Hair dye use and risk of human cancer.

PubMed

Zhang, Yawei; Kim, Christopher; Zheng, Tongzhang

2012-01-01

Over 50% of the adult population will use hair dyes at some point in their lifetimes. Hair dyes consist of various chemicals and the composition of these chemicals vary by hair dye types. Chemicals p-phenylenediamine and aminophenyl have been suggested as possible carcinogens or mutagens in experimental studies. The scientific community has been interested in this potential public health impact and the results of published epidemiological studies are summarized here. The current evidence provides limited evidences on the association between personal hair dye use and human cancer risk, except for the possibility of hematopoietic cancers and to a lesser extent, bladder cancer. Risk appears to be affected by time period of use and by specific genetic polymorphisms. Future studies should investigate potential gene and environment interaction to assess possible genetic susceptibility. Several methodological issues should also be considered in future studies including completed hair dye use information such as on timing, duration, frequency and type of hair dye product use.

Labeling tetracysteine-tagged proteins with biarsenical dyes for live cell imaging.

PubMed

Gaietta, Guido M; Deerinck, Thomas J; Ellisman, Mark H

2011-01-01

Correlation of real-time or time-lapse light microscopy (LM) with electron microscopy (EM) of cells can be performed with biarsenical dyes. These dyes fluorescently label tetracysteine-tagged proteins so that they can be imaged with LM and, upon fluorescent photoconversion of 3,3'-diaminobenzidine tetrahydrochloride (DAB), with EM as well. In the following protocol, cells expressing tetracysteine-tagged proteins are labeled for 1 h with biarsenical dyes. The volumes indicated are for a single 30-mm culture dish containing 2 mL of labeling medium. Scale the suggested volumes up or down depending upon the size of the culture dish used in the labeling. The same procedure can be adapted for longer labeling times by lowering the amount of dye used to 50-100 nM; however, the amount of the competing dithiol EDT is maintained at 10-20 μM. Longer labeling times often produce higher signal-to-noise ratios and cause less trauma to the treated cells prior to imaging.

Treatment of textile dyehouse effluent using ceramic membrane based process in combination with chemical pretreatment.

PubMed

Bhattacharya, Priyankari; Ghosh, Sourja; Majumdar, Swachchha; Bandyopadhyay, Sibdas

2013-10-01

Treatment of highly concentrated dyebath effluent and comparatively dilute composite effluent having mixture of various reactive dyes collected from a cotton fabric dyeing unit was undertaken in the present study. Ceramic microfiltration membrane prepared from a cost effective composition of alumina and clay was used. Prior to microfiltration, a chemical pretreatment was carried out with aluminium sulphate in combination with a polymeric retention aid. An optimum dose of 100 mg/L of aluminium sulphate and 1 ml/L of a commercial flocculant Afilan RAMF was found effective for dye removal (> 98%) from the synthetic solutions of reactive dyes with initial concentration of 150 mg/L in both the single component and two component systems. In the microfiltration study, effect of operating pressure in the permeate flux was observed for both the pretreated and untreated effluents and permeate samples were analyzed for dye concentration, COD, turbidity, TSS, etc. during constant pressure filtration. About 98-99% removal of dyes was obtained in the combined process with COD reduction of 54-64%.

Green dyeing process of modified cotton fibres using natural dyes extracted from Tamarix aphylla (L.) Karst. leaves.

PubMed

Baaka, Noureddine; Mahfoudhi, Adel; Haddar, Wafa; Mhenni, Mohamed Farouk; Mighri, Zine

2017-01-01

This research work involves an eco-friendly dyeing process of modified cotton with the aqueous extract of Tamarix aphylla leaves. During this process, the dyeing step was carried out on modified cotton by several cationising agents in order to improve its dyeability. The influence of the main dyeing conditions (dye bath pH, dyeing time, dyeing temperature, salt addition) on the performances of this dyeing process were studied. The dyeing performances of this process were appreciated by measuring the colour yield (K/S) and the fastness properties of the dyed samples. The effect of mordant type with different mordanting methods on dyeing quality was also studied. The results showed that mordanting gave deeper shades and enhanced fastness properties. In addition, environmental indicators (BOD 5 , COD and COD/BOD 5 ) were used to describe potential improvements in the biodegradability of the dyebath wastewater. Further, HPLC was used to identify the major phenolic compounds in the extracted dye.

Smart photovoltaics based on dye-sensitized solar cells using photochromic spiropyran derivatives as photosensitizers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Shengbo; Ting, Hungkit; Ma, Yingzhuang

2015-05-15

In this paper, smart photovoltaic (SPV) devices, integrating both functions of solar cells and smart windows, was fabricated based on dye-sensitized solar cells using photochromic spiropyran derivatives SIBT as photosensitizers. SPV devices have self-regulated power conversion efficiency (PCE) and light transmission responding to the incident spectra due to the photoisomerization of SIBT. SIBT isomerize from closed-ring form to open-ring form under UV illumination, accompanied with enhanced visible light absorption and electron delocalization. Therefore, increased PCE and absorption in SPV devices were observed under UV treatment and the devices can be restored gradually to the initial status when kept in dark.more » The SPV devices have self-regulation of PCE and sunlight transmission responding to the changing sun spectra in different times of a day, providing a proper energy usage and a better sun-shading.« less

Metabolism in the Uncultivated Giant Sulfide-Oxidizing Bacterium Thiomargarita Namibiensis Assayed Using a Redox-Sensitive Dye

NASA Astrophysics Data System (ADS)

Bailey, J.; Flood, B.; Ricci, E.

2014-12-01

The colorless sulfur bacteria are non-photosynthetic chemolithotrophs that live at interfaces between nitrate, or oxygen, and hydrogen sulfide. In sulfidic settings such as cold seeps and oxygen minimum zones, these bacteria are thought to constitute a critical node in the geochemical cycling of carbon, sulfur, nitrogen, and phosphorous. Many of these bacteria remain uncultivated and their metabolisms and physiologies are incompletely understood. Thiomargarita namibiensis is the largest of these sulfur bacteria, with individual cells reaching millimetric diameters. Despite the current inability to maintain a Thiomargarita culture in the lab, their large size allows for individual cells to be followed in time course experiments. Here we report on the novel use of a tetrazolium-based dye that measures the flux of NADH production from catabolic pathways via a colorimetric response. Staining with this dye allows for metabolism to be detected, even in the absence of observable cell division. When coupled to microscopy, this approach also allows for metabolism in Thiomargaritato be differentiated from that of epibionts or contaminants in xenic samples. The results of our tetrazolium dye-based assay suggests that Thiomargarita is the most metabolically versatile under anoxic conditions where it appears capable of using acetate, succinate, formate, thiosulfate, citrate, thiotaurine, hydrogen sulfide, and perhaps hydrogen as electron donors. Under hypoxic conditions, staining results suggest the utilization of acetate, citrate, and hydrogen sulfide. Cells incubated under oxic conditions showed the weakest tetrazolium staining response, and then only to hydrogen sulfide and questionably succinate. These initial results using a redox sensitive dye suggest that Thiomargarita is most metabolically versatile under anaerobic and hypoxic conditions. The results of this assay can be further evaluated using molecular approaches such as transcriptomics, as well as provide cultivation strategies.

Improvement of methyl orange dye biotreatment by a novel isolated strain, Aeromonas veronii GRI, by SPB1 biosurfactant addition.

PubMed

Mnif, Inès; Maktouf, Sameh; Fendri, Raouia; Kriaa, Mouna; Ellouze, Semia; Ghribi, Dhouha

2016-01-01

Aeromonas veronii GRI (KF964486), isolated from acclimated textile effluent after selective enrichment on azo dye, was assessed for methyl orange biodegradation potency. Results suggested the potential of this bacterium for use in effective treatment of azo-dye-contaminated wastewaters under static conditions at neutral and alkaline pH value, characteristic of typical textile effluents. The strain could tolerate higher doses of dyes as it was able to decolorize up to 1000 mg/l. When used as microbial surfactant to enhance methyl orange biodecolorization, Bacillus subtilis SPB1-derived lipopeptide accelerated the decolorization rate and maximized slightly the decolorization efficiency at an optimal concentration of about 0.025%. In order to enhance the process efficiency, a Taguchi design was conducted. Phytotoxicity bioassay using sesame and radish seeds were carried out to assess the biotreatment effectiveness. The bacterium was able to effectively decolorize the azo dye when inoculated with an initial optical density of about 0.5 with 0.25% sucrose, 0.125% yeast extract, 0.01% SPB1 biosurfactant, and when conducting an agitation phase of about 24 h after static incubation. Germination potency showed an increase toward the nonoptimized conditions indicating an improvement of the biotreatment. When comparing with synthetic surfactants, a drastic decrease and an inhibition of orange methyl decolorization were observed in the presence of CTAB and SDS. The nonionic surfactant Tween 80 had a positive effect on methyl orange biodecolorization. Also, studies ensured that methyl orange removal by this strain could be due to endocellular enzymatic activities. To conclude, the addition of SPB1 bioemulsifier reduced energy costs by reducing effective decolorization period, biosurfactant stimulated bacterial decolorization method may provide highly efficient, inexpensive, and time-saving procedure in treatment of textile effluents.

An efficient adsorption of indigo carmine dye from aqueous solution on mesoporous Mg/Fe layered double hydroxide nanoparticles prepared by controlled sol-gel route.

PubMed

Ahmed, M A; Brick, A A; Mohamed, A A

2017-05-01

A new approach for removal of indigo carmine blue (IC) dye which is extensively used in jeans manufacture was successfully performed on novel mesoporous [LDH] nanoparticles prepared by sol-gel route using CTAB as shape and pore directing agent. The physicochemical features were monitored by X-ray diffraction (XRD), Fourier transformer infra-red (FTIR), N 2 adsorption-desorption isotherm, Field emission electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM). The influence of reaction parameters affecting dye adsorption including contact time, initial dye concentration, pH and temperature were investigated. Textural analysis and HRTEM images indicate the existence of mesoporous spherical nanoparticles of size = 26 nm connected to each other's and embedded large numbers of mesopores of average pore radius = 43.5 Å. A successful adsorption of IC on LDH nanoparticles of surface area = 85.6 m 2 /g at various pH with maximum adsorption capacity = 62.8 mg/g at pH = 9.5. Langmuir model is more favorable to describe the adsorption of IC rather than Freundlich model which reflecting the preferential formation of monolayer on the surface of LDH. Both film diffusion and the intraparticle diffusion affect the dye adsorption. The values of enthalpy change (ΔH) for and (ΔS) are + 28.18 and + 0.118 kJ/mol, respectively indicating that the removal process is endothermic. The results indicated that LDH nanoparticles conserved a good activity even after five consecutive cycles of reuse. Our results suggest that mesoporous LDH nanoparticles are considered a potential novel adsorbent for remediation of wastewater containing IC. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of a novel dextran-based flocculant on treatment of dye wastewater: Effect of kaolin particles.

PubMed

Zhao, Chuanliang; Zheng, Huaili; Sun, Yongjun; Zhang, Shixin; Liang, Jianjun; Liu, Yongzhi; An, Yanyan

2018-05-30

Graft modified flocculants have recently received increasing attention in the field of water treatment as they have the combinative advantages of synthetic and natural polymeric flocculants. In this work, surface-active monomer benzyl(methacryloyloxyethyl)dimethylammonium chloride (BMDAC) was selected to graft on dextran (DX) with high molecular weight (10.3 × 10 6  g/mol) produced through enzyme-catalyzed process in order to remove dissolved dyes from wastewater. The flocculant (DAB) was fabricated by ultrasound initiated polymerization technique, and the structure characterization of FTIR, 1 H/ 12 C NMR, XRD and XPS spectrum confirmed the successful grafting. Then the Congo red (CR) removal efficiency by DAB was optimized based on the flocculation conditions, including wastewater initial pH, flocculant dosage and initial dye concentration. The effect of suspended solids on the removal of dyes was evaluated in kaolin-CR simulated wastewater. The results indicated that the optimal removal efficiency of CR was 68.1% and 88.2% in single CR and kaolin-CR flocculation system, respectively. The improvement of removal efficiency was attributed to the fact that partial CR molecules were adsorbed onto kaolin particles before flocculation, and were synergistically flocculated accompanied by kaolin particles. Finally, the flocculation mechanism was discussed by a detailed investigation of the zeta potentials, FTIR and XPS spectra of flocs, which can provide important reference for optimizing the flocculation conditions and designing novel high-performance flocculants. Copyright © 2018. Published by Elsevier B.V.

Removal of reactive blue 19 dye by sono, photo and sonophotocatalytic oxidation using visible light.

PubMed

Khan, Muhammad Abdul Nasir; Siddique, Maria; Wahid, Fazli; Khan, Romana

2015-09-01

An efficient sonophotocatalytic degradation of reactive blue 19 (RB 19) dye was successfully carried out using sulfur-doped TiO2 (S-TiO2) nanoparticles. The effect of various treatment processes that is sonolysis, photolysis, catalysis, sonocatalysis, photocatalysis, and sonophotocatalysis were investigated for RB 19 removal. S-TiO2 were synthesized in 1, 3 and 5 wt.% of sulfur by sol-gel process and characterized by X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX), UV-Visible diffuse reflectance spectra (DRS). The results confirm anatase phase of TiO2, porous agglomerate structure, and a red shift in the absorbance spectra of S-TiO2. The dye degradation was studied by using UV-Vis spectrophotometer at λ max=594 nm. The reaction parameters such as pH, catalyst dosage, initial dye concentration, ultrasonic power and effect of sulfur doping in different weight percent were studied to find out the optimum degradation conditions. Optimum conditions were found as: S-TiO2=5 wt.%, catalyst (S-TiO2 5 wt.%)=50mg, RB 19 solution concentration=20 mg L(-1), pH=3, ultrasound power=100 and operating temperature=25°C. The response of 5 wt.% S-TiO2 was found better than 1 and 3 wt.% S-TiO2 and other forms TiO2. The sonophotocatalysis process was superior to other methods. During this process the ultrasound cavitation and photocatalysis water splitting takes place which leads to the generation of OH. As reveled by the GCMS results the reactive blue 19 (20 mg L(-1)) was degraded to 90% within 120 min. The S-TiO2 sonophotocatalysis system was studied for the first time for dye degradation and was found practicable, efficient and cost effective for the degradation of complex and resistant dyes such as RB19. Copyright © 2015. Published by Elsevier B.V.

Sono-assisted adsorption of a textile dye on milk vetch-derived charcoal supported by silica nanopowder.

PubMed

Jorfi, Sahand; Darvishi Cheshmeh Soltani, Reza; Ahmadi, Mehdi; Khataee, Alireza; Safari, Mahdi

2017-02-01

This study was performed to assess the efficiency of silica nanopowder (SNP)/milk vetch-derived charcoal (MVDC) nanocomposite coupled with the ultrasonic irradiation named sono-adsorption process for treating water-contained Basic Red 46 (BR46) dye. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and Fourier transform infrared spectroscopy (FT-IR) were performed for the characterization of as-prepared adsorbent. The sono-assisted adsorption process was optimized using response surface optimization on the basis of central composite design by the application of quadratic model. Accordingly, the color removal can be retained more than 93% by an initial BR46 concentration of 8 mg/L, sonication time of 31 min, adsorbent dosage of 1.2 g/L and initial pH of 9. The pseudo-second order kinetic model described the sono-assisted adsorption of BR46 reasonably well (R 2  > 0.99). The intra-particular diffusion kinetic model pointed out that the sono-assisted adsorption of BR46 onto SNP/MVDC nanocomposite was diffusion controlled as well as that ultrasonication enhanced the diffusion rate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Degradation pathway of the naphthalene azo dye intermediate 1-diazo-2- naphthol-4-sulfonic acid using Fenton's reagent.

PubMed

Zhu, Nanwen; Gu, Lin; Yuan, Haiping; Lou, Ziyang; Wang, Liang; Zhang, Xin

2012-08-01

Degradation of naphthalene dye intermediate 1-diazo-2- naphthol-4-sulfonic acid (1,2,4-Acid) by Fenton process has been studied in depth for the purpose of learning more about the reactions involved in the oxidation of 1,2,4-Acid. During 1,2,4-Acid oxidation, the solution color initially takes on a dark red, then to dark black associated with the formation of quinodial-type structures, and then goes to dark brown and gradually disappears, indicating a fast degradation of azo group. The observed color changes of the solution are a result of main reaction intermediates, which can be an indicator of the level of oxidization reached. Nevertheless, complete TOC removal is not accomplished, in accordance with the presence of resistant carboxylic acids at the end of the reaction. The intermediates generated along the reaction time have been identified and quantified. UPLC-(ESI)-TOF-HRMS analysis allows the detection of 19 aromatic compounds of different size and complexity. Some of them share the same accurate mass but appear at different retention time, evidencing their different molecular structures. Heteroatom oxidation products like SO(4)(2-) have also been quantified and explanations of their release are proposed. Short-chain carboxylic acids are detected at long reaction time, as a previous step to complete the process of dye mineralization. Finally, considering all the findings of the present study and previous related works, the evolution from the original 1,2,4-Acid to the final products is proposed in a general reaction scheme. Copyright © 2012 Elsevier Ltd. All rights reserved.

Time of travel and dispersion in a selected reach of Roberts Creek, Clayton County, Iowa

USGS Publications Warehouse

Kolpin, D.W.; Kalkhoff, S.J.

1992-01-01

Time of travel was determined by dye tracing, using rhodamine WT as the tracer. One dyeinjection site and three sampling sites were used to measure time of travel. Two dye-tracing tests were conducted at discharges having flow-duration values of 48 and 80 percent. The discharges at the time of the two dye-tracing tests approximated medium- and low-flow conditions. The average stream velocity in the study area was 0.23 foot per second during medium-flow conditions, March 20 to 22,1990, and 0.07 foot per second during low-flow conditions, April 30 to May 12, 1990. The injected dye dispersed in a plume that lasted about 18 hours during medium flow and about 64 hours during low flow at the downstream site.

Nucleophilic Addition of Reactive Dyes on Amidoximated Acrylic Fabrics

PubMed Central

El-Shishtawy, Reda M.; El-Zawahry, Manal M.; Abdelghaffar, Fatma; Ahmed, Nahed S. E.

2014-01-01

Seven reactive dyes judiciously selected based on chemical structures and fixation mechanisms were applied at 2% owf of shade on amidoximated acrylic fabrics. Amidoximated acrylic fabric has been obtained by a viable amidoximation process. The dyeability of these fabrics was evaluated with respect to the dye exhaustion, fixation, and colour strength under different conditions of temperature and dyeing time. Nucleophilic addition type reactive dyes show higher colour data compared to nucleophilic substitution ones. FTIR studies further implicate the binding of reactive dyes on these fabrics. A tentative mechanism is proposed to rationalize the high fixation yield obtained using nucleophilic addition type reactive dyes. Also, the levelling and fastness properties were evaluated for all dyes used. Excellent to good fastness and levelling properties were obtained for all samples irrespective of the dye used. The result of investigation offers a new method for a viable reactive dyeing of amidoximated acrylic fabrics. PMID:25258720

Facile synthesis and characterisation of AlNs using Protein Rich Solution extracted from sewage sludge and its application for ultrasonic assisted dye adsorption: Isotherms, kinetics, mechanism and RSM design.

PubMed

Mary Ealias, Anu; Saravanakumar, M P

2018-01-15

Protein Rich Solution (PRS) was prepared from the sewage sludge with ultrasonic assistance. With PRS, aluminium based nanosheet like materials (AlNs) were synthesised for the ultrasonic removal of Congo Red (CR) and Crystal Violet (CV) dyes. PRS was characterised by UV, EEM and NMR spectral analysis. AlNs were characterised by FTIR, XRD, TGA, BET, SEM, AFM, TEM and XPS analysis. The point of zero charge of AlNs was found to be 5.4. The BET analysis ensured that the average pore diameter and total pore volume of AlNs as 8.464 nm and 0.11417 cc/g respectively. The efficacy of AlNs for the removal of toxic dyes was tested by performing Response surface methodology (RSM) designed experiments. The effect of sonication time, dosage and initial concentration on dye removal was studied at an optimised pH value. Langmuir, Freundlich and Temkin isotherm models were examined. The maximum adsorption capacity was found to be 121.951 and 105.263 mg/g for CR and CV respectively. The kinetic models like pseudo-first order, pseudo-second order, Elovich and intra-particle diffusion were examined to understand the mechanism behind it. The results revealed that the use of ultrasonication enhanced the mass transfer. The experimental studies on the influence of ultrasound power indicated a positive relation with the removal efficiency. The results of thermodynamic study revealed that the process was spontaneous and exothermic for both the dyes. The increase in ionic strength increased the removal efficiency for both CR and CV. RSM predicted the optimum adsorbent dosages as 0.16 g for 50 mg/L of CR and 0.12 g for 100 mg/L of CV dye solutions. The values of half-life and fractional adsorption for both CR and CV suggested that the low cost AlNs has high potential to remove the toxic industrial dyes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal of azo dye using Fenton and Fenton-like processes: Evaluation of process factors by Box-Behnken design and ecotoxicity tests.

PubMed

Fernandes, Neemias Cintra; Brito, Lara Barroso; Costa, Gessyca Gonçalves; Taveira, Stephânia Fleury; Cunha-Filho, Marcílio Sérgio Soares; Oliveira, Gisele Augusto Rodrigues; Marreto, Ricardo Neves

2018-06-06

The conventional treatment of textile effluents is usually inefficient in removing azo dyes and can even generate more toxic products than the original dyes. The aim of the present study was to optimize the process factors in the degradation of Disperse Red 343 by Fenton and Fenton-like processes, as well as to investigate the ecotoxicity of the samples treated under optimized conditions. A Box-Behnken design integrated with the desirability function was used to optimize dye degradation, the amount of residual H 2 O 2 [H 2 O 2residual ], and the ecotoxicity of the treated samples (lettuce seed, Artemia salina, and zebrafish in their early-life stages). Dye degradation was affected only by catalyst concentration [Fe] in both the Fenton and Fenton-like processes. In the Fenton reaction, [H 2 O 2residual ] was significantly affected by initial [H 2 O 2 ] and its interaction with [Fe]; however, in the Fenton-like reaction, it was affected by initial [H 2 O 2 ] only. A. salina mortality was affected by different process factors in both processes, which suggests the formation of different toxic products in each process. The desirability function was applied to determine the best process parameters and predict the responses, which were confirmed experimentally. Optimal conditions facilitated the complete degradation of the dye without [H 2 O 2residual ] or toxicity for samples treated with the Fenton-like process, whereas the Fenton process induced significant mortality for A. salina. Results indicate that the Fenton-like process is superior to the Fenton reaction to degrade Disperse Red 343. Copyright © 2018 Elsevier B.V. All rights reserved.

Combination of forward osmosis (FO) process with coagulation/flocculation (CF) for potential treatment of textile wastewater.

PubMed

Han, Gang; Liang, Can-Zeng; Chung, Tai-Shung; Weber, Martin; Staudt, Claudia; Maletzko, Christian

2016-03-15

A novel combination of forward osmosis (FO) process with coagulation/flocculation (CF) (FO-CF) has been experimentally conceived for the treatment and reuse of textile wastewater. FO is employed to spontaneously recover water from the wastewater via osmosis and thus effectively reduces its volume with a dramatically enhanced dye concentration. CF is then applied to precipitate and remove dyes from the FO concentrated stream with much improved efficiency and reduced chemical dosage. The FO-CF hybrid system exhibits unique advantages of high water flux and recovery rate, well controlled membrane fouling, high efficiency, and minimal environmental impact. Using a lab-made thin-film composite (TFC) FO membrane, an initial water flux (Jw) of 36.0 L m(-2) h(-1) with a dye rejection of 99.9% has been demonstrated by using 2 M NaCl as the draw solution and synthetic textile wastewater containing multiple textile dyes, inorganic salts and organic additives as the feed under the FO mode. The Jw could be maintained at a high value of 12.0 L m(-2) h(-1) even when the recovery rate of the wastewater reaches 90%. Remarkable reverse fouling behavior has also been observed where the Jw of the fouled membrane can be almost fully restored to the initial value by physical flushing without using any chemicals. Due to the great dye concentration in the FO concentrated wastewater stream, the CF process could achieve more than 95% dye removal with a small dosage of coagulants and flocculants at 500-1000 ppm. The newly developed FO-CF hybrid process may open up new exploration of alternative technologies for the effective treatment and reuse of textile effluents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enzymatic reduction of azo and indigoid compounds.

PubMed

Pricelius, S; Held, C; Murkovic, M; Bozic, M; Kokol, V; Cavaco-Paulo, A; Guebitz, G M

2007-11-01

A customer- and environment-friendly method for the decolorization azo dyes was developed. Azoreductases could be used both to bleach hair dyed with azo dyes and to reduce dyes in vat dyeing of textiles. A new reduced nicotinamide adenine dinucleotide-dependent azoreductase of Bacillus cereus, which showed high potential for reduction of these dyes, was purified using a combination of ammonium sulfate precipitation and chromatography and had a molecular mass of 21.5 kDa. The optimum pH of the azoreductase depended on the substrate and was within the range of pH 6 to 7, while the maximum temperature was reached at 40 degrees C. Oxygen was shown to be an alternative electron acceptor to azo compounds and must therefore be excluded during enzymatic dye reduction. Biotransformation of the azo dyes Flame Orange and Ruby Red was studied in more detail using UV-visible spectroscopy, high-performance liquid chromatography, and mass spectrometry (MS). Reduction of the azo bonds leads to cleavage of the dyes resulting in the cleavage product 2-amino-1,3 dimethylimidazolium and N approximately 1 approximately ,N approximately 1 approximately -dimethyl-1,4-benzenediamine for Ruby Red, while only the first was detected for Flame Orange because of MS instability of the expected 1,4-benzenediamine. The azoreductase was also found to reduce vat dyes like Indigo Carmine (C.I. Acid Blue 74). Hydrogen peroxide (H(2)O(2)) as an oxidizing agent was used to reoxidize the dye into the initial form. The reduction and oxidation mechanism of Indigo Carmine was studied using UV-visible spectroscopy.

Direct analysis of textile dyes from trace fibers by automated microfluidics extraction system coupled with Q-TOF mass spectrometer for forensic applications.

PubMed

Sultana, Nadia; Gunning, Sean; Furst, Stephen J; Garrard, Kenneth P; Dow, Thomas A; Vinueza, Nelson R

2018-05-19

Textile fiber is a common form of transferable trace evidence at the crime scene. Different techniques such as microscopy or spectroscopy are currently being used for trace fiber analysis. Dye characterization in trace fiber adds an important molecular specificity during the analysis. In this study, we performed a direct trace fiber analysis method via dye characterization by a novel automated microfluidics device (MFD) dye extraction system coupled with a quadrupole-time-of-flight (Q-TOF) mass spectrometer (MS). The MFD system used an in-house made automated procedure which requires only 10μL of organic solvent for the extraction. The total extraction and identification time by the system is under 12min. A variety of sulfonated azo and anthraquinone dyes were analyzed from ∼1mm length nylon fiber samples. This methodology successfully characterized multiple dyes (≥3 dyes) from a single fiber thread. Additionally, it was possible to do dye characterization from single fibers with a diameter of ∼10μm. The MFD-MS system was used for elemental composition and isotopic distribution analysis where MFD-MS/MS was used for structural characterization of dyes on fibers. Copyright © 2018 Elsevier B.V. All rights reserved.

Synthesis and Characterization of Modified BiOCl and Their Application in Adsorption of Low-Concentration Dyes from Aqueous Solution

NASA Astrophysics Data System (ADS)

Zhao, Qihang; Xing, Yongxing; Liu, Zhiliang; Ouyang, Jing; Du, Chunfang

2018-03-01

The synthesis and characterization of BiOCl and Fe3+-grafted BiOCl (Fe/BiOCl) is reported that are developed as efficient adsorbents for the removal of cationic dyes rhodamine B (RhB) and methylene blue (MB) as well as anionic dyes methyl orange (MO) and acid orange (AO) from aqueous solutions with low concentration of 0.01 0.04 mmol/L. Characterizations by various techniques indicate that Fe3+ grafting induced more open porous structure and higher specific surface area. Both BiOCl and Fe/BiOCl with negatively charged surfaces showed excellent adsorption efficiency toward cationic dyes, which could sharply reach 99.6 and nearly 100% within 3 min on BiOCl and 97.0 and 98.0% within 10 min on Fe/BiOCl for removing RhB and MB, respectively. However, Fe/BiOCl showed higher adsorption capacity than BiOCl toward ionic dyes. The influence of initial dye concentration, temperature, and pH value on the adsorption capacity is comprehensively studied. The adsorption process of RhB conforms to Langmuir adsorption isotherm and pseudo-second-order kinetic feature. The excellent adsorption capacities of as-prepared adsorbents toward cationic dyes are rationalized on the basis of electrostatic attraction as well as open porous structure and high specific surface area. In comparison with Fe/BiOCl, BiOCl displays higher selective efficiency toward cationic dyes in mixed dye solutions.

Kinetics of ozone-initiated oxidation of textile dye, Amaranth in aqueous systems.

PubMed

Dachipally, Purnachandar; Jonnalagadda, Sreekanth B

2011-01-01

The ozone facilitated oxidation mechanism of water soluble azo anionic dye, amaranth (Am) was investigated monitoring the depletion kinetics of the dye spectrometrically at 521 nm. The oxidation kinetics of the dye by ozone was studied under semi-batch conditions, by bubbling ozone enriched oxygen through the aqueous reaction mixture of dye, as function of flow rate, ionic strength, [O(3)] and pH variations. With excess concentration of ozone and other reagents and low [amaranth], reaction followed pseudo-first-order kinetics with respect to the dye. Added neutral salts had marginal effect on the reaction rate and the variation of pH from 7 to 2 and 7 to 12 exerted only small increases in the reaction rate suggesting molecular ozone possibly is the principle reactive species in oxidation of dye. The reaction order with respect ozone was near unity and it varied slightly with pH and flow rate variations. The overall second-order rate constant for the reaction was (105 ± 4) M(-1) min(-1). The main oxidation products immediately after amaranth decolorization were identified. The reaction mechanism and overall rate law were proposed. After spiking the seawater, river water and wastewaters with Amaranth dye, the reaction rates and trends in BOD and COD under control and natural conditions were investigated. The rate of depletion of the dye in natural waters was relatively lower, but the ozonation process significantly decreased both the BOD and COD levels.

Ni/MgAlO regeneration for catalytic wet air oxidation of an azo-dye in trickle-bed reaction.

PubMed

Vallet, Ana; Ovejero, Gabriel; Rodríguez, Araceli; Peres, José A; García, Juan

2013-01-15

Active nickel catalysts (7 wt%) supported over Mg-Al mixed oxides have been recently developed and it has also been demonstrated that they are also highly selective in Catalytic Wet air Oxidation (CWAO) of dyes. CWAO of Chromotrope 2R (C2R) has been studied using a trickle bed reactor employing temperatures from 100 to 180 °C, liquid flow rates from 0.1 to 0.7 mL min(-1) and initial dye concentration from 10 to 50 ppm. Total pressure and air flow were 25 bar and 300 mL min(-1), respectively. The catalyst showed a very stable activity up to 24 h on stream with an average TOC conversion of 82% at 150 °C and T(r)=0.098 g(Ni) min mL(-1). After the reaction, a 1.1 wt% C of carbonaceous deposit is formed onto the catalyst and a diminution of 30% of the surface area with respect of the fresh catalyst was observed. An increase in the space time gave higher TOC conversions up to T(r)=0.098 g(Ni) min mL(-1), attaining values of 80% at 180 °C. The performance of TOC and dye removal does not decrease after two regeneration cycles. In total, a 57 h effective reaction has been carried out with no loss of catalytic activity. Copyright © 2012 Elsevier B.V. All rights reserved.

Application of zeolite-activated carbon macrocomposite for the adsorption of Acid Orange 7: isotherm, kinetic and thermodynamic studies.

PubMed

Lim, Chi Kim; Bay, Hui Han; Neoh, Chin Hong; Aris, Azmi; Abdul Majid, Zaiton; Ibrahim, Zaharah

2013-10-01

In this study, the adsorption behavior of azo dye Acid Orange 7 (AO7) from aqueous solution onto macrocomposite (MC) was investigated under various experimental conditions. The adsorbent, MC, which consists of a mixture of zeolite and activated carbon, was found to be effective in removing AO7. The MC were characterized by scanning electron microscopy (SEM), energy dispersive X-ray, point of zero charge, and Brunauer-Emmett-Teller surface area analysis. A series of experiments were performed via batch adsorption technique to examine the effect of the process variables, namely, contact time, initial dye concentration, and solution pH. The dye equilibrium adsorption was investigated, and the equilibrium data were fitted to Langmuir, Freundlich, and Tempkin isotherm models. The Langmuir isotherm model fits the equilibrium data better than the Freundlich isotherm model. For the kinetic study, pseudo-first-order, pseudo-second-order, and intraparticle diffusion model were used to fit the experimental data. The adsorption kinetic was found to be well described by the pseudo-second-order model. Thermodynamic analysis indicated that the adsorption process is a spontaneous and endothermic process. The SEM, Fourier transform infrared spectroscopy, ultraviolet-visible spectral and high performance liquid chromatography analysis were carried out before and after the adsorption process. For the phytotoxicity test, treated AO7 was found to be less toxic. Thus, the study indicated that MC has good potential use as an adsorbent for the removal of azo dye from aqueous solution.

Continuous-wave organic dye lasers and methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shapira, Ofer; Chua, Song-Liang; Zhen, Bo

2014-09-16

An organic dye laser produces a continuous-wave (cw) output without any moving parts (e.g., without using flowing dye streams or spinning discs of solid-state dye media to prevent photobleaching) and with a pump beam that is stationary with respect to the organic dye medium. The laser's resonant cavity, organic dye medium, and pump beam are configured to excite a lasing transition over a time scale longer than the associated decay lifetimes in the organic dye medium without photobleaching the organic dye medium. Because the organic dye medium does not photobleach when operating in this manner, it may be pumped continuouslymore » so as to emit a cw output beam. In some examples, operation in this manner lowers the lasing threshold (e.g., to only a few Watts per square centimeter), thereby facilitating electrical pumping for cw operation.« less

Comparative study on ultrasonic assisted adsorption of dyes from single system onto Fe3O4 magnetite nanoparticles loaded on activated carbon: Experimental design methodology.

PubMed

Bagheri, Ahmad Reza; Ghaedi, Mehrorang; Asfaram, Arash; Bazrafshan, Ali Akbar; Jannesar, Ramin

2017-01-01

The present study the ultrasound assisted adsorption of dyes in single system onto Fe 3 O 4 magnetite nanoparticles loaded on activated carbon (Fe 3 O 4 -MNPs-AC) was described following characterization and identification of this adsorbent by conventional techniques likes field emission scanning electron microscopy, transmission electron microscopy, particle-size distribution, X-ray diffraction and Fourier transform infrared spectroscopy. A central composite design in conjunction with a response surface methodology according to f-test and t-test for recognition and judgment about significant term led to construction of quadratic model which represent relation among responses and effective terms. This model has unique ability to predict adsorption data behavior over a large space around central and optimum point. Accordingly Optimum conditions for well and quantitative removal of present dyes was obtained best operation and conditions: initial SY, MB and EB dyes concentration of 15, 15 and 25mgL -1 , 4.0, 6.0 and 5.0 of pH, 360, 360 and 240s sonication time and 0.04, 0.03 and 0.032g of Fe 3 O 4 -MNPs-AC. Replication of similar experiment (N=5) guide that average removal percentage of SY, MB and EB were found to be 96.63±2.86%, 98.12±1.67% and 99.65±1.21% respectively. Good agreement and closeness of Predicted and experimental result and high adsorption capacity of dyes in short time strongly confirm high suitability of present method for waste water treatment, while easy separation of present nanoparticle and its good regeneration all support good applicability of Fe 3 O 4 -MNPs-AC for waste water treatment. The kinetic study can be represented by combination of pseudo second-order and intraparticle diffusion. The obtained maximum adsorption capacities correspond to Langmuir as best model for representation of experimental data correspond to dyes adsorption onto Fe 3 O 4 -MNPs-AC were 76.37, 78.76 and 102.00mgg -1 for SY, MB and EB, respectively. In addition, the performance comparison of ultrasound-assisted, magnetic stirrer assisted and vortex assisted adsorption methods demonstrates that ultrasound is an effective and good choice for facilitation of adsorption process via. Compromise of simple and facile diffusion. Copyright © 2016 Elsevier B.V. All rights reserved.

Adsorption of reactive blue BF-5G dye by soybean hulls: kinetics, equilibrium and influencing factors.

PubMed

Honorio, Jacqueline Ferandin; Veit, Márcia Teresinha; Gonçalves, Gilberto da Cunha; de Campos, Élvio Antonio; Fagundes-Klen, Márcia Regina

2016-01-01

The textile industry is known for the high use of chemicals, such as dyes, and large volumes of effluent that contaminate waters, a fact that has encouraged research and improved treatment techniques. In this study, we used unprocessed soybean hulls for the removal of reactive blue BF-5G dye. The point of zero charge of soybean hulls was 6.76. Regarding the speed of agitation in the adsorption process, the resistance to mass transfer that occurs in the boundary layer was eliminated at 100 rpm. Kinetics showed an experimental amount of dye adsorbed at equilibrium of 57.473 mg g(-1) obtained under the following conditions: dye initial concentration = 400 mg L(-1); diameter of particle = 0.725 mm; dosage = 6 g L(-1); pH 2; 100 rpm; temperature = 30 °C; and duration of 24 hours. The pseudo-second order best showed the dye removal kinetics. The adsorption isotherms performed at different temperatures (20, 30, 40 and 50 °C) showed little variation in the concentration range assessed, being properly adjusted by the Langmuir isotherm model. The maximum capacity of dye adsorption was 72.427 mg g(-1) at 30 °C. Since soybean hull is a low-cost industrial byproduct, it proved to be a potential adsorbent for the removal of the textile dye assessed.

Sorption of hydrophilic dyes on anodic aluminium oxide films and application to pH sensing.

PubMed

Silina, Yuliya E; Kuchmenko, Tatyana A; Volmer, Dietrich A

2015-02-07

The sorption of selected hydrophilic pH-sensitive dyes (bromophenol blue, bromothymol blue, bromocresol purple, alizarin red, methyl orange, congo red, rhodamine 6G) on films of anodized aluminium oxide (AAO) was investigated in this study. Depth and pore structure of the AAO channels were adjusted by changing electrolysis time and current density during treatment of aluminium foil in oxalic acid, sulfosalycilic acid and sulfuric acid at concentration levels between 0.2 and 0.6 M. The dyes were immobilized on the AAO surface by direct saturation of the films in dye solutions. It was shown by scanning electron microscopy and X-ray spectral analysis that the dyes penetrated into the AAO channels by more than 1.5 μm, even at static saturation conditions. The anionic dyes linked to the porous AAO surface exhibited differential shifts of the UV absorption bands in their acidic/basic forms. By combining several dyes, the films have an application range between pH = 0.5-9 in aqueous media. The dye-modified AAO film was a simple, portable, inexpensive and reusable pH sensor with very fast response time and clear colour transitions.

Theoretical Study of Ultrafast Electron Injection into a Dye/TiO2 System in Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Lin, Chundan; Xia, Qide; Li, Kuan; Li, Juan; Yang, Zhenqing

2018-06-01

The ultrafast injection of excited electrons in dye/TiO2 system plays a critical role, which determines the device's efficiency in large part. In this work, we studied the geometrical structures and electronic properties of a dye/TiO2 composite system for dye-sensitized solar cells (DSSCs) by using density functional theory, and we analyzed the mechanism of ultrafast electron injection with emphasis on the power conversion efficiency. The results show that the dye SPL103/TiO2 (101) surface is more stable than dye SPL101. The electron injection driving force of SPL103/TiO2 (101) is 3.55 times that of SPL101, indicating that SPL103/TiO2 (101) has a strong ability to transfer electrons. SPL103 and SPL101/TiO2 (101) both have fast electron transfer processes, and especially the electron injection time of SPL103/TiO2 (101) is only 1.875 fs. The results of this work are expected to provide a new understanding of the mechanism of electron injection in dyes/TiO2 systems for use in highly effective DSSCs.

Synthesis, characterization, swelling and dye adsorption properties of starch incorporated acrylic gels.

PubMed

Mandal, Bidyadhar; Ray, Samit Kumar

2015-11-01

Several hydrogels were prepared by a free radical polymerization of acrylic acid (AA), sodium acrylate (SA) and AA/hydroxy ethyl methacrylate (HEMA) in the presence of starch in water. These starch incorporated acrylic gels were prepared by varying the concentration of the initiator, monomer, crosslinker and the starch. The resulting gels were characterized by FTIR, SEM, XRD, DTA-TGA, pH at point zero charge (PZC), swelling and the diffusion in water. The gels showed high adsorption and removal% of Safranine T (ST) and Brilliant Cresyl Blue (BCB) dyes from water. The swelling and the adsorption data were fitted to different kinetic models and isotherms. Amongst the three kinds of gels, the starch incorporated sodium polyacrylate gel showed the highest adsorption of 9.7-85.3mg/L (97-61% removal) of BCB dye and 9.1-83mg/L (91-60% removal) of ST dye for a feed dye concentration of 10-140mg/L. Copyright © 2015 Elsevier B.V. All rights reserved.

Exploring the potential of anaerobic sulfate reduction process in treating sulfonated diazo dye: Microbial community analysis using bar-coded pyrosequencing.

PubMed

Rasool, Kashif; Shahzad, Asif; Lee, Dae Sung

2016-11-15

Anaerobic decolorization and biotransformation of azo dye was investigated in a sulfate-reducing environment. Batch reactor studies were performed with mixed cultures of anaerobic sulfate-reducing bacteria (SRBs) enriched from anaerobic digester sludge. Complete sulfate and color removal were achieved in batch experiments with different initial dye concentrations (50-2500mg/L) and 1000mg/L of sulfate. Induction of various oxidoreductive enzyme activities such as phenol oxidase, veratryl alcohol oxidase, lignin peroxidase, and azo reductase was studied to understand their involvement in dye metabolism under anoxic environment. The degradation of Cotton Red B was confirmed using high-performance liquid chromatography and gas chromatography-mass spectroscopy. Sulfidogenic sludge demonstrated excellent dye degradation and mineralization ability, producing aniline and 1,4-diamino benzene as metabolites. A barcoded 16S rRNA gene-pyrosequencing approach was used to assess the bacterial diversity in the sludge culture and a phylogenetic tree was constructed for sulfate-reducing bacteria. Copyright © 2016 Elsevier B.V. All rights reserved.

Photocatalytic degradation of Maxilon C.I. basic dye using CS/CoFe2O4/GONCs as a heterogeneous photo-Fenton catalyst prepared by gamma irradiation.

PubMed

Al-Kahtani, Abdullah A; Abou Taleb, Manal F

2016-05-15

CS/CF/GONCs were synthesized via gamma irradiation cross-linking method with the aid of sonication. The nanocomposites exhibited a photo-Fenton catalytic feature for the degradation of Maxilon C.I. basic dye in aqueous medium using sunlight. The effects of pH, H2O2 concentration, and dosage of the catalyst, on the degradation rates of the dyes were examined. The optimal degradation rate was reached with 10mM H2O2 at pH 9.5. It was verified that the Maxilon C.I. basic dye degradation rate fits a pseudo-first-order kinetics for different initial concentrations of Maxilon C.I. dye. Fourth cyclic tests for Maxilon C.I. degradation showed that the magnetic catalyst was very stable, recoverable, highly active, and easy to separate using an external magnet. Hence, this magnetic catalyst has potential use in organic pollutant removal. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultrafast Fabrication of Flexible Dye-Sensitized Solar Cells by Ultrasonic Spray-Coating Technology

PubMed Central

Han, Hyun-Gyu; Weerasinghe, Hashitha C.; Min Kim, Kwang; Soo Kim, Jeong; Cheng, Yi-Bing; Jones, David J.; Holmes, Andrew B.; Kwon, Tae-Hyuk

2015-01-01

This study investigates novel deposition techniques for the preparation of TiO2 electrodes for use in flexible dye-sensitized solar cells. These proposed new methods, namely pre-dye-coating and codeposition ultrasonic spraying, eliminate the conventional need for time-consuming processes such as dye soaking and high-temperature sintering. Power conversion efficiencies of over 4.0% were achieved with electrodes prepared on flexible polymer substrates using this new deposition technology and N719 dye as a sensitizer. PMID:26420466

Dynamic Flow Velocity Mapping from Fluorescent Dye Transit Times in the Brain Surface Microcirculation of Anesthetized Rats and Mice.

PubMed

Hoshikawa, Ryo; Kawaguchi, Hiroshi; Takuwa, Hiroyuki; Ikoma, Yoko; Tomita, Yutaka; Unekawa, Miyuki; Suzuki, Norihiro; Kanno, Iwao; Masamoto, Kazuto

2016-08-01

This study aimed to develop a new method for mapping blood flow velocity based on the spatial evolution of fluorescent dye transit times captured with CLSFM in the cerebral microcirculation of anesthetized rodents. The animals were anesthetized with isoflurane, and a small amount of fluorescent dye was intravenously injected to label blood plasma. The CLSFM was conducted through a closed cranial window to capture propagation of the dye in the cortical vessels. The transit time of the dye over a certain distance in a single vessel was determined with automated image analyses, and average flow velocity was mapped in each vessel. The average flow velocity measured in the rat pial artery and vein was 4.4 ± 1.2 and 2.4 ± 0.5 mm/sec, respectively. A similar range of flow velocity to those of the rats was observed in the mice; 4.9 ± 1.4 and 2.0 ± 0.9 mm/sec, respectively, although the vessel diameter in the mice was about half of that in the rats. Flow velocity in the cerebral microcirculation can be mapped based on fluorescent dye transit time measurements with conventional CLSFM in experimental animals. © 2016 John Wiley & Sons Ltd.

Combined use of two membrane-potential-sensitive dyes for determination of the Galvani potential difference across a biomimetic oil/water interface.

PubMed

Yoshimura, Tatsuya; Nagatani, Hirohisa; Osakai, Toshiyuki

2014-05-01

The fluorescence behavior of anionic membrane-potential-sensitive dyes, bis-(1,3-dibutylbarbituric acid) trimethine oxonol (DiBAC4(3)) and bis-(1,3-diethylthiobarbituric acid)trimethine oxonol (DiSBAC2(3)), at a biomimetic 1,2-dichloroethane (DCE)/water (W) interface was studied by the mean of potential-modulated fluorescence (PMF) spectroscopy. The respective dyes gave a well-defined PMF signal due to the adsorption/desorption at the DCE/W interface. It was also found that the potentials where the two dyes gave the PMF signals were different by about 100 mV. We then attempted a combined use of the two dyes for determination of the Galvani potential difference across the DCE/W interface. When 40 μM DiBAC4(3) and 15 μM DiSBAC2(3) were initially added to the W phase, distinctly different spectra were obtained for different interfacial potentials. The ratio of the PMF signal intensities at 530 and 575 nm (the fluorescence maximum wavelengths for the respective dyes) showed a clear dependence on the interfacial potential. These results suggested the potential utility of the combined use of two dyes for the determination of membrane potentials in vivo.

The optical biomedical sensors for DNA detection and imaging based on two-photon excited luminescent styryl dyes: phototoxic influence on the DNA

NASA Astrophysics Data System (ADS)

Yashchuk, Valeriy M.; Kudrya, Vladislav Yu.; Losytskyy, Mykhaylo Yu.; Tokar, Valentyna P.; Yarmoluk, Sergiy M.; Dmytruk, Igor M.; Prokopets, Vadym M.; Kovalska, Vladyslava B.; Balanda, Anatoliy O.; Kryvorotenko, Dmytro V.; Ogul'chansky, Tymish Yu.

2007-06-01

The optical absorption, fluorescence and phosphorescence of the novel styryl dyes developed for the fluorescent detection of DNA were investigated. The energy structures of dye molecules as well as spectral manifestations of the dyes aggregate formation and interaction with DNA were studied. The dramatic increase (up to 1000 times) of the fluorescence intensity of dyes in the presence of DNA was observed. The photostability and phototoxic influence on the DNA of several styryl dyes were studied by analyzing absorption, fluorescence and phosphorescence spectra of these dyes and dye-DNA systems. Changes of the optical density value of dye-DNA solutions caused by the visible light irradiation were fixed in the wavelength regions of the DNA absorption and of the dye absorption. Fluorescence emission of dye-DNA complexes upon two-photon excitation (TPE) at wavelength 1064 nm with the 20 ns pulsed YAG: Nd3+ laser and at 840 nm with the 90 fs pulsed Ti:sapphire laser was registered. The values of two-photon absorption cross-sections of dye-DNA complexes were evaluated.

Dye adsorption mechanisms in TiO2 films, and their effects on the photodynamic and photovoltaic properties in dye-sensitized solar cells.

PubMed

Hwang, Kyung-Jun; Shim, Wang-Geun; Kim, Youngjin; Kim, Gunwoo; Choi, Chulmin; Kang, Sang Ook; Cho, Dae Won

2015-09-14

The adsorption mechanism for the N719 dye on a TiO2 electrode was examined by the kinetic and diffusion models (pseudo-first order, pseudo-second order, and intra-particle diffusion models). Among these methods, the observed adsorption kinetics are well-described using the pseudo-second order model. Moreover, the film diffusion process was the main controlling step of adsorption, which was analysed using a diffusion-based model. The photodynamic properties in dye-sensitized solar cells (DSSCs) were investigated using time-resolved transient absorption techniques. The photodynamics of the oxidized N719 species were shown to be dependent on the adsorption time, and also the adsorbed concentration of N719. The photovoltaic parameters (Jsc, Voc, FF and η) of this DSSC were determined in terms of the dye adsorption amounts. The solar cell performance correlates significantly with charge recombination and dye regeneration dynamics, which are also affected by the dye adsorption amounts. Therefore, the photovoltaic performance of this DSSC can be interpreted in terms of the adsorption kinetics and the photodynamics of oxidized N719.

Continuous Digital Light Processing (cDLP): Highly Accurate Additive Manufacturing of Tissue Engineered Bone Scaffolds.

PubMed

Dean, David; Jonathan, Wallace; Siblani, Ali; Wang, Martha O; Kim, Kyobum; Mikos, Antonios G; Fisher, John P

2012-03-01

Highly accurate rendering of the external and internal geometry of bone tissue engineering scaffolds effects fit at the defect site, loading of internal pore spaces with cells, bioreactor-delivered nutrient and growth factor circulation, and scaffold resorption. It may be necessary to render resorbable polymer scaffolds with 50 μm or less accuracy to achieve these goals. This level of accuracy is available using Continuous Digital Light processing (cDLP) which utilizes a DLP(®) (Texas Instruments, Dallas, TX) chip. One such additive manufacturing device is the envisionTEC (Ferndale, MI) Perfactory(®). To use cDLP we integrate a photo-crosslinkable polymer, a photo-initiator, and a biocompatible dye. The dye attenuates light, thereby limiting the depth of polymerization. In this study we fabricated scaffolds using the well-studied resorbable polymer, poly(propylene fumarate) (PPF), titanium dioxide (TiO(2)) as a dye, Irgacure(®) 819 (BASF [Ciba], Florham Park, NJ) as an initiator, and diethyl fumarate as a solvent to control viscosity.

Removal of methyl orange and methylene blue dyes from aqueous solution using lala clam (Orbicularia orbiculata) shell

NASA Astrophysics Data System (ADS)

Eljiedi, Arwa Alseddig Ahmed; Kamari, Azlan

2017-05-01

Textile effluents are considered as potential sources of water pollution because they contain toxic dyes. In the present study, lala clam shell was used as an alternative low-cost adsorbent for the removal of two harmful dyes, namely methyl orange (MO) and methylene blue (MB) from aqueous solution. Batch adsorption studies were carried out by varying experimental parameters such as solution pH, initial concentration and adsorbent dosage. The optimum pH values for MO and MB removal were pH 2.0 and pH 8.0, respectively. At an initial MO and MB concentration of 20 mg/L, the maximum removal percentage of MO and MB were 18.9 % and 81.3 %, respectively. The adsorption equilibrium data were correlated with both Langmuir and Freundlich isotherm models. The biomass adsorbent was characterised using Field Emission Scanning Electron Microscope (FESEM) and Fourier Transform Infrared Spectrometer (FTIR). Results from this study suggest that lala clam shell, a fishery waste, can be beneficial for water treatment.

CALCULATION OF ELAPSED DECIMAL TIME FOR DYE-TRACING STUDIES: APPLICATION OF A BASELINE TIME STANDARD (Journal Article)

EPA Science Inventory

Calculation of time of travel from dye-tracing studies in karstic aquifers is critical to establishing pollutant arrival times from points of inflow to resurgences, calculation of subsurface flow velocities, and determining other important transport parameters such as longitudin...

Performance and characterization of a new tannin-based coagulant

NASA Astrophysics Data System (ADS)

Beltrán-Heredia, J.; Sánchez-Martín, J.; Gómez-Muñoz, C.

2012-09-01

Diethanolamine and formaldehyde were employed to cationize tannins from black wattle. This novel coagulant called CDF was functionally characterized in removing sodium dodecylbenzene sulfonate (anionic surfactant) and Palatine Fast Black WAN (azoic dye). Refined tannin-derived commercial coagulants exhibited similar efficiency, while CDF presented higher coagulant ability than alum, a usual coagulant agent. Low doses of CDF (ca. 100 mg L-1) were able to remove more than 70 % of surfactant and more than 85 % of dye (initial pollutant concentration of ca. 100 mg L-1) and it presented no temperature affection and worked at a relatively wide pH range. Surfactant and dye removal responded to the classical coagulant-and-adsorption models, such as Frumkin-Fowler-Guggenheim or Gu and Zhu in the case of surfactant, and Langmuir and Freundlich in the case of dye.

78 FR 72630 - Initiation of Antidumping and Countervailing Duty Administrative Reviews and Request for...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-03

... Ding Ying Printing & Dyeing Co. Ltd..... Shanghai Guoxing Metal Products Co. Ltd Shanghai Jianhai... of initiation of the review, will determine, consistent with FAG Italia v. United States, 291 F.3d...

Binding patterns and structure-affinity relationships of food azo dyes with lysozyme: a multitechnique approach.

PubMed

Peng, Wei; Ding, Fei; Peng, Yu-Kui; Jiang, Yu-Ting; Zhang, Li

2013-12-18

Food dyes serve to beguile consumers: they are often used to imitate the presence of healthful, colorful food produce such as fruits and vegetables. But considering the hurtful impact of these chemicals on the human body, it is time to thoroughly uncover the toxicity of these food dyes at the molecular level. In the present contribution, we have examined the molecular reactions of protein lysozyme with model food azo compound Color Index (C.I.) Acid Red 2 and its analogues C.I. Acid Orange 52, Solvent Yellow 2, and the core structure of azobenzene using a combination of biophysical methods at physiological conditions. Fluorescence, circular dichroism (CD), time-resolved fluorescence, UV-vis absorption as well as computer-aided molecular modeling were used to analyze food dye affinity, binding mode, energy transfer, and the effects of food dye complexation on lysozyme stability and conformation. Fluorescence emission spectra indicate complex formation at 10(-5) M dye concentration, and this corroborates time-resolved fluorescence results showing the diminution in the tryptophan (Trp) fluorescence mainly via a static type (KSV = 1.505 × 10(4) M(-1)) and Förster energy transfer. Structural analysis displayed the participation of several amino acid residues in food dye protein adducts, with hydrogen bonds, π-π and cation-π interactions, but the conformation of lysozyme was unchanged in the process, as derived from fluorescence emission, far-UV CD, and synchronous fluorescence spectra. The overall affinity of food dye is 10(4) M(-1) and there exists only one kind of binding domain in protein for food dye. These data are consistent with hydrophobic probe 8-anilino-1-naphthalenesulfonic acid (ANS) displacement, and molecular modeling manifesting the food dye binding patch was near to Trp-62 and Trp-63 residues of lysozyme. On the basis of the computational analyses, we determine that the type of substituent on the azobenzene structure has a powerful influence on the toxicity of food dyes. Results from this work testify that model protein, though an indirect method, provides a more comprehensive profile of the essence of toxicity evaluation of food dyes.

Jackfruit (Artocarpus heterophyllus lamk) wood waste as a textile natural dye by micowave-assisted extraction method

NASA Astrophysics Data System (ADS)

Qadariyah, Lailatul; Gala, Selfina; Widoretno, Dhaniar Rulandri; Kunhermanti, Delita; Bhuana, Donny S.; Sumarno, Mahfud, Mahfud

2017-05-01

The development of technology causes most of textile industries in Indonesia prefer to use synthetic dyes in the fabric dyeing process. In fact, synthetic dyes is able to have negative effect since it is is toxic to the health of workers and environment. To resolve this issues, one way to do is to use natural dyes. One of untapped potential in Indonesia is wood waste of jackfruit from furniture industry. Jackfruit wood itself containing dyestuffs which gives yellow color pigment so that it can be used as an alternative source of natural dyes. The purpose of this research is to study the effect of extraction time, mass to solvent volume ratio, and microwave power to yield of dyes. The extract of dye analyzed by UV-Visible Spectrophotometer and GC-MS, along the coloring and endurance tests of natural dyes on fabric and compare it with synthetic dyes. In this research, material is going to be extracted is the wood of jackfruit (Artocarpus heterophyllus lamk) with material size between 35 mesh - 60 mesh. The extraction process is done by using ethanol 96%. Extraction using MAE is carried out at the ratio of materials to solvent of 0,02-0,1 g/mL, the microwave power of 100-800 Watt, and the extraction time of 10-90 minutes. The conclusion is at microwave power of 400 Watt, material to solvent ratio of the 0,02 g/mL, the yield is 3,39% while at microwave power of 600 Watt, material to solvent ratio of the 0,02 g/mL, the yield is 3,67% with extraction time of 30 minutes. The highest recovery from ethanol 96% solvent is 60,41%. The result of UV-Vis Spectrophotometry and GC-MS test show that there is a chromophore compound in the extract of natural dye. The test results show the natural dyes of jackfruit wood can be used to coloring on the textile because it can gives staining result permanently.

Development of Encapsulated Dye for Surface Impact Damage Indicator System.

DTIC Science & Technology

1987-09-01

GROUP SUB-GROUP Composites Ultrasonics Dye Impact Microcapsules 11 04 NDE polyurethane 11 1 0Encapsulation Paint 19. ABSTRACT (Continue on reverse if...encapsulation, microencapsule incorporation into the USAF polyurethane paint, dnd initial correlation study of impact damage to impact coating indication. It is...project were to: 1. Refine the microcapsule formulation to be compatible with MIL-C-83286 paint. 2. Fabricate composite panels from isotropic graphite

Zeolite Y encapsulated with Fe-TiO2 for ultrasound-assisted degradation of amaranth dye in water.

PubMed

Alwash, Atheel Hassan; Abdullah, Ahmad Zuhairi; Ismail, Norli

2012-09-30

A new heterogeneous catalyst for sonocatalytic degradation of amaranth dye in water was synthesized by introducing titania into the pores of zeolite (NaY) through ion exchange method while Fe (III) was immobilized on the encapsulated titanium via impregnation method. XRD results could not detect any peaks for titanium oxide or Fe(2)O(3) due to its low loading. The UV-vis analysis proved a blue shift toward shorter wavelength after the loading of Ti into NaY while a red shift was detected after the loading of Fe into the encapsulated titanium. Different reaction variables such as TiO(2) content, amount of Fe, pH values, amount of hydrogen peroxide, catalyst loading and the initial dye concentration were studied to estimate their effect on the decolorization efficiency of amaranth. The maximum decolorization efficiency achieved was 97.5% at a solution pH of 2.5, catalyst dosage of 2 g/L, 20 mmol/100 mL of H(2)O(2) and initial dye concentration of 10 mg/L. The new heterogeneous catalyst Fe/Ti-NaY was a promising catalyst for this reaction and showed minimum Fe leaching at the end of the reaction. Copyright © 2012 Elsevier B.V. All rights reserved.

Treatment of artificial wastewater containing two azo textile dyes by vertical-flow constructed wetlands.

PubMed

Hussein, Amjad; Scholz, Miklas

2018-03-01

The release of untreated dye textile wastewater into receiving streams is unacceptable not only for aesthetic reasons and its negative impacts on aquatic life but also because numerous dyes are toxic and carcinogenic to humans. Strategies, as of now, used for treating textile wastewaters have technical and economical restrictions. The greater part of the physico-chemical methods, which are used to treat this kind of wastewater, are costly, produce large amounts of sludge and are wasteful concerning some soluble dyes. In contrast, biological treatments such as constructed wetlands are cheaper than the traditional methods, environmental friendly and do not produce large amounts of sludge. Synthetic wastewater containing Acid Blue 113 (AB113) and Basic Red 46 (BR46) has been added to laboratory-scale vertical-flow construction wetland systems, which have been planted with Phragmites australis (Cav.) Trin. ex Steud. (common reed). The concentrations 7 and 208 mg/l were applied for each dye at the hydraulic contact times of 48 and 96 h. Concerning the low concentrations of BR46 and AB113, the unplanted wetlands are associated with significant (ρ < 0.05) reduction performances, if compared with planted wetlands concerning the removal of dyes. For the high concentrations of AB113, BR46 and a mixture of both of them, wetlands with long contact times were significantly (ρ < 0.05) better than wetlands that had short contact times in terms of dye, colour and chemical oxygen demand reductions. Regarding nitrate nitrogen (NO 3 -N), the reduction percentage rates of AB113, BR46 and a mixture dye of both of them were between 85 and 100%. For low and high inflow dye concentrations, best removals were generally recorded for spring and summer, respectively.

Near-infrared voltage-sensitive fluorescent dyes optimized for optical mapping in blood-perfused myocardium.

PubMed

Matiukas, Arvydas; Mitrea, Bogdan G; Qin, Maochun; Pertsov, Arkady M; Shvedko, Alexander G; Warren, Mark D; Zaitsev, Alexey V; Wuskell, Joseph P; Wei, Mei-de; Watras, James; Loew, Leslie M

2007-11-01

Styryl voltage-sensitive dyes (e.g., di-4-ANEPPS) have been used successfully for optical mapping in cardiac cells and tissues. However, their utility for probing electrical activity deep inside the myocardial wall and in blood-perfused myocardium has been limited because of light scattering and high absorption by endogenous chromophores and hemoglobin at blue-green excitation wavelengths. The purpose of this study was to characterize two new styryl dyes--di-4-ANBDQPQ (JPW-6003) and di-4-ANBDQBS (JPW-6033)--optimized for blood-perfused tissue and intramural optical mapping. Voltage-dependent spectra were recorded in a model lipid bilayer. Optical mapping experiments were conducted in four species (mouse, rat, guinea pig, and pig). Hearts were Langendorff perfused using Tyrode's solution and blood (pig). Dyes were loaded via bolus injection into perfusate. Transillumination experiments were conducted in isolated coronary-perfused pig right ventricular wall preparations. The optimal excitation wavelength in cardiac tissues (650 nm) was >70 nm beyond the absorption maximum of hemoglobin. Voltage sensitivity of both dyes was approximately 10% to 20%. Signal decay half-life due to dye internalization was 80 to 210 minutes, which is 5 to 7 times slower than for di-4-ANEPPS. In transillumination mode, DeltaF/F was as high as 20%. In blood-perfused tissues, DeltaF/F reached 5.5% (1.8 times higher than for di-4-ANEPPS). We have synthesized and characterized two new near-infrared dyes with excitation/emission wavelengths shifted >100 nm to the red. They provide both high voltage sensitivity and 5 to 7 times slower internalization rate compared to conventional dyes. The dyes are optimized for deeper tissue probing and optical mapping of blood-perfused tissue, but they also can be used for conventional applications.

Evidence for biphasic uncoating during HIV-1 infection from a novel imaging assay

PubMed Central

2013-01-01

Background Uncoating of the HIV-1 core plays a critical role during early post-fusion stages of infection but is poorly understood. Microscopy-based assays are unable to easily distinguish between intact and partially uncoated viral cores. Results In this study, we used 5-ethynyl uridine (EU) to label viral-associated RNA during HIV production. At early time points after infection with EU-labeled virions, the viral-associated RNA was stained with an EU-specific dye and was detected by confocal microscopy together with viral proteins. We observed that detection of the viral-associated RNA was specific for EU-labeled virions, was detected only after viral fusion with target cells, and occurred after an initial opening of the core. In vitro staining of cores showed that the opening of the core allowed the small molecule dye, but not RNase A or antibodies, inside. Also, staining of the viral-associated RNA, which is co-localized with nucleocapsid, decays over time after viral infection. The decay rate of RNA staining is dependent on capsid (CA) stability, which was altered by CA mutations or a small molecule inducer of HIV-1 uncoating. While the staining of EU-labeled RNA was not affected by inhibition of reverse transcription, the kinetics of core opening of different CA mutants correlated with initiation of reverse transcription. Analysis of the E45A CA mutant suggests that initial core opening is independent of complete capsid disassembly. Conclusions Taken together, our results establish a novel RNA accessibility-based assay that detects an early event in HIV-1 uncoating and can be used to further define this process. PMID:23835323

Optical Properties of Nano-Spherical Gold Doped Dye Solution Hybrid

NASA Astrophysics Data System (ADS)

Hoa, D. Q.; Lien, N. T. H.; Ha, C. V.; Nhung, T. H.; Long, P.

2011-03-01

Gold nanoparticles with average diameter of 16 nm which are coated with Cetrimonium Bromide (CTAB) by chemical method are dissolved in dye solution at different concentrations. The absorption spectra of the dye mixture appeared almost unchanged at low concentrations of gold nanoparticles (around 1×1014 cm-3) despite its fluorescence intensity increased many-fold. Energy transfer from gold nanoparticles to dye molecules occurs through surface plasmon resonance(SPR). The fluorescence of rhodamine 610 (Rh610) dye molecules co-adsorbed within 16 nm gold nanoparticles assemblies can be useful for enhancing gain in lasing emission. An increase in laser efficiency by a factor of one and half times stronger compared to the single Rh610 dye suggest the potential of using the mixture of rhodamine dye with gold nanoparticles as laser medium in the configuration of quenching distributed feedback dye laser.

Biosorption of reactive dye from textile wastewater by non-viable biomass of Aspergillus niger and Spirogyra sp.

PubMed

Khalaf, Mahmoud A

2008-09-01

The potential of Aspergillus niger fungus and Spirogyra sp., a fresh water green algae, was investigated as a biosorbents for removal of reactive dye (Synazol) from its multi component textile wastewater. The results showed that pre-treatment of fungal and algal biomasses with autoclaving increased the removal of dye than pre-treatment with gamma-irradiation. The effects of operational parameters (pH, temperature, biomass concentration and time) on dye removal were examined. The results obtained revealed that dried autoclaved biomass of A. niger and Spirogyra sp. exhibited maximum dye removal (88% and 85%, respectively) at pH3, temperature 30 degrees C and 8 gl(-1)(w/v) biomass conc. after 18h contact time. The stability and efficiency of both organisms in the long-term repetitive operation were also investigated. The results showed that the non-viable biomasses possessed high stability and efficiency of dye removal over 3 repeated batches.

40 CFR 63.4330 - By what date must I conduct the initial compliance demonstration?

Code of Federal Regulations, 2010 CFR

2010-07-01

... operations, the organic HAP emission rate for the initial compliance period was equal to or less than the applicable emission limit in Table 1 to this subpart and for dyeing/finishing operations, the mass fraction...

Decolorization and Degradation of Batik Dye Effluent using Ganoderma lucidum

NASA Astrophysics Data System (ADS)

Pratiwi, Diah; Indrianingsih, A. W.; Darsih, Cici; Hernawan

2017-12-01

Batik is product of traditional Indonesia culture that developed into a large textile industry. Synthetic dyes which widely used in textile industries including batik. Colour can be removed from wastewater effluent by chemical, physical, and biology methods. Bioremediation is one of the methods that used for processing colored effluent. Isolated White-rot fungi Ganoderma lucidum was used for bioremediation process for batik effluent. G. lucidum was developed by G. lucidum cultivation on centers of mushroom farmer Media Agro Merapi Kaliurang, Yogyakarta. The batik effluent was collected from a private small and medium Batik enterprises located at Petir, Rongkop, Gunungkidul Regency. The aim of the study were to optimize decolorization of Naphtol Black (NB) using G. lucidum. The effect of process parameters like incubation time and dye concentration on dye decolorization and COD degradation was studied. G. lucidum were growth at pH 5-6 and temperature 25°C at various Naphtol Black dye with concentration 20 ppm, 50 ppm, and 100 ppm for 30 day incubation time. The result from this study increased decolorization in line with the increasing of COD degradation. Increasing percentage of decolorization and COD degradation gradually increased with incubation time and dye concentration. The maximum decolorization and COD reduction were found to be 60,53% and 81,03%. G. lucidum had potential to decolorized and degraded COD for NB dye effluent on higher concentration.

Dye-sensitized solar cells based on purple corn sensitizers

NASA Astrophysics Data System (ADS)

Phinjaturus, Kawin; Maiaugree, Wasan; Suriharn, Bhalang; Pimanpaeng, Samuk; Amornkitbamrung, Vittaya; Swatsitang, Ekaphan

2016-09-01

Natural dye extracted from husk, cob and silk of purple corn, were used for the first time as photosensitizers in dye sensitized solar cells (DSSCs). The dye sensitized solar cells fabrication process has been optimized in terms of solvent extraction. The resulting maximal efficiency of 1.06% was obtained from purple corn husk extracted by acetone. The ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and incident photon-to-current efficiency (IPCE) were employed to characterize the natural dye and the DSSCs.

Emergence of dominant initiation sites for interictal spikes in rat neocortex

PubMed Central

Vitantonio, Daniel; Xu, Weifeng; Geng, Xinling; Wolff, Brian S.; Takagaki, Kentaroh; Motamedi, Gholam K.

2015-01-01

Neuronal populations with unbalanced inhibition can generate interictal spikes (ISs), where each IS starts from a small initiation site and then spreads activation across a larger area. We used in vivo voltage-sensitive dye imaging to map the initiation site of ISs in rat visual cortex disinhibited by epidural application of bicuculline methiodide. Immediately after the application of bicuculline, the IS initiation sites were widely distributed over the entire disinhibited area. After ∼10 min, a small number of sites became “dominant” and initiated the majority of the ISs throughout the course of imaging. Such domination also occurred in cortical slices, which lack long-range connections between the cortex and subcortical structures. This domination of IS initiation sites may allow timing-related plasticity mechanisms to provide a spatial organization where connections projecting outward from the dominant initiation site become strengthened. Understanding the spatiotemporal organization of IS initiation sites may contribute to our understanding of epileptogenesis in its very early stages, because a dominant IS initiation site with strengthened outward connectivity may ultimately develop into a seizure focus. PMID:26445866

Molecular engineering of fluorescein dyes as complementary absorbers in dye co-sensitized solar cells

DOE PAGES

Pepe, Giulio; Cole, Jacqueline M.; Waddell, Paul G.; ...

2016-09-22

Fluorescein dye derivatives exhibit extended optical absorption up to 500 nm, rendering these compounds suitable as co-absorbers in dye-sensitized solar cells (DSCs). A molecular engineering approach is presented, which embraces this intrinsic optical attribute of fluoresceins, while modifying the dye chemistry to enhance their light harvesting efficiency, in order to effectively tailor them for DSC applications. This approach first realizes relationships between the molecular structure and the optoelectronic properties for a series of five a priori known (parent) fluorescein dyes: 5-carboxyfluorescein (1), a mixture of m-carboxyfluorescein where m = 5 or 6 (2), 5-carboxyfluorescein diacetate (3), 6-carboxyfluorescein diacetate (4), amore » mixture of n-carboxy-2',7'-dichlorofluorescein diacetate where n = 5 or 6 (5). The first step in this approach combines, where available, experimental and computational methods so that electronic structure calculations can also be validated for representative fluorescein dyes. Such calculations can then be used reliably to predict the structure and properties of fluorescein dyes for cases where experimental data are lacking. Structure-function relationships established from this initial step inform the selection of parent dye 1 that is taken forward to the second step in molecular engineering: in silico chemical derivation to re-functionalize 1 for DSC applications. For this purpose, computational calculations are used to extend the charge conjugation in 1 between its donor and acceptor moieties. These structural modifications result in a bathochromic shift of the lowest excitation by ~1.3-1.9 eV (100-170 nm), making the dye optically absorb in the visible region. Further calculations on dye molecules adsorbed onto the surface of a TiO 2 cluster are used to investigate the dye sensitization behavior via dye adsorption energies and anchoring modes. The results of this theoretical investigation lead to two molecularly engineered fluoresceins being proposed to act as co-sensitizers together with a rhodamine dye. This combination of three dyes ensures chemical compatibility, panchromatic absorption, and restores optical absorption dipping otherwise observed in a DSC device at ~350-400 nm owing to the I-/I- 3 electrolyte. Altogether, the results of this study demonstrate that molecular engineering can be used to identify suitable chemical modifications for organic dyes with improved light harvesting properties for photovoltaic applications.« less

Molecular engineering of fluorescein dyes as complementary absorbers in dye co-sensitized solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pepe, Giulio; Cole, Jacqueline M.; Waddell, Paul G.

Fluorescein dye derivatives exhibit extended optical absorption up to 500 nm, rendering these compounds suitable as co-absorbers in dye-sensitized solar cells (DSCs). A molecular engineering approach is presented, which embraces this intrinsic optical attribute of fluoresceins, while modifying the dye chemistry to enhance their light harvesting efficiency, in order to effectively tailor them for DSC applications. This approach first realizes relationships between the molecular structure and the optoelectronic properties for a series of five a priori known (parent) fluorescein dyes: 5-carboxyfluorescein (1), a mixture of m-carboxyfluorescein where m = 5 or 6 (2), 5-carboxyfluorescein diacetate (3), 6-carboxyfluorescein diacetate (4), amore » mixture of n-carboxy-2',7'-dichlorofluorescein diacetate where n = 5 or 6 (5). The first step in this approach combines, where available, experimental and computational methods so that electronic structure calculations can also be validated for representative fluorescein dyes. Such calculations can then be used reliably to predict the structure and properties of fluorescein dyes for cases where experimental data are lacking. Structure-function relationships established from this initial step inform the selection of parent dye 1 that is taken forward to the second step in molecular engineering: in silico chemical derivation to re-functionalize 1 for DSC applications. For this purpose, computational calculations are used to extend the charge conjugation in 1 between its donor and acceptor moieties. These structural modifications result in a bathochromic shift of the lowest excitation by ~1.3-1.9 eV (100-170 nm), making the dye optically absorb in the visible region. Further calculations on dye molecules adsorbed onto the surface of a TiO 2 cluster are used to investigate the dye sensitization behavior via dye adsorption energies and anchoring modes. The results of this theoretical investigation lead to two molecularly engineered fluoresceins being proposed to act as co-sensitizers together with a rhodamine dye. This combination of three dyes ensures chemical compatibility, panchromatic absorption, and restores optical absorption dipping otherwise observed in a DSC device at ~350-400 nm owing to the I-/I- 3 electrolyte. Altogether, the results of this study demonstrate that molecular engineering can be used to identify suitable chemical modifications for organic dyes with improved light harvesting properties for photovoltaic applications.« less

Triple dye plus rubbing alcohol versus triple dye alone for umbilical cord care.

PubMed

Suliman, Alawia K; Watts, Heidi; Beiler, Jessica; King, Tonya S; Khan, Sana; Carnuccio, Marybeth; Paul, Ian M

2010-01-01

Current practices for umbilical cord care vary across centers, but the evidence regarding these practices and their impact on cord separation, complications, and health care use are limited. The objective of this study was to compare the effect of triple dye alone (brilliant green, crystal violet, and proflavine hemisulfate) versus triple dye plus rubbing alcohol (isopropyl alcohol) twice daily on time to umbilical cord separation, complications, and health care use. For the 90 newborns who completed the study, there were no significant differences between treatment groups for time to cord separation, cord-related morbidities, or cord-related urgent care. Based on these study results, there does not appear to be significant benefit to the addition of twice daily applications of rubbing alcohol to neonatal umbilical cords following triple dye treatment after birth.

Soybean peroxidase-mediated degradation of an azo dye– a detailed mechanistic study

PubMed Central

2013-01-01

Background Peroxidases are emerging as an important class of enzymes that can be used for the efficient degradation of organic pollutants. However, detailed studies identifying the various intermediates produced and the mechanisms involved in the enzyme-mediated pollutant degradation are not widely published. Results In the present study, the enzymatic degradation of an azo dye (Crystal Ponceau 6R, CP6R) was studied using commercially available soybean peroxidase (SBP) enzyme. Several operational parameters affecting the enzymatic degradation of dye were evaluated and optimized, such as initial dye concentration, H2O2 dosage, mediator amount and pH of the solution. Under optimized conditions, 40 ppm dye solution could be completely degraded in under one minute by SBP in the presence of H2O2 and a redox mediator. Dye degradation was also confirmed using HPLC and TOC analyses, which showed that most of the dye was being mineralized to CO2 in the process. Conclusions Detailed analysis of metabolites, based on LC/MS results, showed that the enzyme-based degradation of the CP6R dye proceeded in two different reaction pathways- via symmetric azo bond cleavage as well as asymmetric azo bond breakage in the dye molecule. In addition, various critical transformative and oxidative steps such as deamination, desulfonation, keto-oxidation are explained on an electronic level. Furthermore, LC/MS/MS analyses confirmed that the end products in both pathways were small chain aliphatic carboxylic acids. PMID:24308857

Light amplification and lasing from dyes doped in DNA-complex thin films prepared by soaking method

NASA Astrophysics Data System (ADS)

Kawabe, Yutaka; Suzuki, Takemasa; Iisaka, You

2014-08-01

An alternative fabrication method for dye-doped DNA-surfactant complex films was developed and amplified spontaneous emission (ASE) and lasing under low energy optical pumping were demonstrated. In this new preparation technique, thin DNA-cethyltrimethylammonium (CTMA) complex films made by a spin coating method were stained with a hemicyanine dye by soaking them in acetone solution of the dye for one day. Molar ratio of the dye to DNA base pair for the final products was estimated to be 0.2, the value was much higher than those achieved via usual mixing method. ASE threshold value under pumping of a pulsed frequency-doubled YAG laser was about 0.3 mJ/cm2. Laser emission was also attained under the excitation with two interfering beams forming a dynamic grating of gain coefficient. Durability test indicated that 70% of their initial performance was maintained after 1 hour of continuous pumping. The technique was applied to water soluble dyes because the DNA complex was insoluble to water as well as acetone. We employed anionic Eosin Y dye, succeeding in sample formation and ASE emission. Different types of surfactants were also complexed with DNA, showing variation of emission peak wavelength. These results give a clue about the structure of the complex or interaction modes between DNA and surfactants, strongly suggesting that dye molecules are not intercalated into nor bound to DNA double strand directly, but are incorporated in the complex system via ion-exchange process or aggregating with cationic surfactants.

Effect of degree of deacetylation of chitosan on adsorption capacity and reusability of chitosan/polyvinyl alcohol/TiO2 nano composite.

PubMed

Habiba, Umma; Joo, Tan Chin; Siddique, Tawsif A; Salleh, Areisman; Ang, Bee Chin; Afifi, Amalina M

2017-11-01

The chitosan/polyvinyl alcohol/TiO 2 composite was synthesized. Two different degrees of deacetylation of chitosan were prepared by hydrolysis to compare the effectiveness of them. The composite was analyzed via field emission scanning electron microscopy, Fourier transform infrared, X-ray diffraction, thermal gravimetric analysis, weight loss test and adsorption study. The FTIR and XRD results proved the interaction among chitosan, PVA and TiO 2 without any chemical reaction. It was found that, chitosan with higher degree of deacetylation has better stability. Furthermore, it also showed that higher DD of chitosan required less time to reach equilibrium for methyl orange. The adsorption followed the pseudo-second-order kinetic model. The Langmuir and Freundlich isotherm models were fitted well for isotherm study. Adsorption capacity was higher for the composite containing chitosan with higher DD. The dye removal rate was independent of the dye's initial concentration. The adsorption capacity was increased with temperature and it was found from reusability test that the composite containing chitosan with higher DD is more reusable. It was notable that adsorption capacity was even after 15 runs. Therefore, chitosan/PVA/TiO 2 composite can be a very useful material for dye removal. Copyright © 2017 Elsevier B.V. All rights reserved.

Numerical simulation of double‐diffusive finger convection

USGS Publications Warehouse

Hughes, Joseph D.; Sanford, Ward E.; Vacher, H. Leonard

2005-01-01

A hybrid finite element, integrated finite difference numerical model is developed for the simulation of double‐diffusive and multicomponent flow in two and three dimensions. The model is based on a multidimensional, density‐dependent, saturated‐unsaturated transport model (SUTRA), which uses one governing equation for fluid flow and another for solute transport. The solute‐transport equation is applied sequentially to each simulated species. Density coupling of the flow and solute‐transport equations is accounted for and handled using a sequential implicit Picard iterative scheme. High‐resolution data from a double‐diffusive Hele‐Shaw experiment, initially in a density‐stable configuration, is used to verify the numerical model. The temporal and spatial evolution of simulated double‐diffusive convection is in good agreement with experimental results. Numerical results are very sensitive to discretization and correspond closest to experimental results when element sizes adequately define the spatial resolution of observed fingering. Numerical results also indicate that differences in the molecular diffusivity of sodium chloride and the dye used to visualize experimental sodium chloride concentrations are significant and cause inaccurate mapping of sodium chloride concentrations by the dye, especially at late times. As a result of reduced diffusion, simulated dye fingers are better defined than simulated sodium chloride fingers and exhibit more vertical mass transfer.

Resonant third-order optical nonlinearities of thin films containing J-aggregates of a cyanine dye or a squarylium dye

NASA Astrophysics Data System (ADS)

Li, Zhongyu; Jin, Zhaohui; Kasatani, Kazuo

2005-01-01

The third-order optical nonlinearities and responses of thin films containing the J-aggregates of a cyanine dye or a squarylium dye were measured using the degenerate four-wave mixing (DFWM) technique under resonant conditions. The sol-gel silica coating films containing the J-aggregates of the cyanine dye, NK-3261, are stable at room temperature and durable against laser beam irradiation. The temporal profiles of the DFWM signal were measured with a time resolution of 0.3 ps, and were found to consist of at least three components, i.e., the coherent instantaneous nonlinear response and the two slow responses with delay time constants of ca. 1.0 ps and ca. 5.6 ps. The contribution of the later was small. The electronic component of the effective third-order optical nonlinear susceptibility of the film had value of as high as ca. 3.0 x 10-7 esu. We also studied the neat film of a squarylium dye J-aggregates. The temporal profile of the DFWM signal of the neat film of squarylium dye was also found to consist of at least three components, the coherent instantaneous nonlinear response and the delayed response with decay time constants of ca. 0.6 ps and ca. 6.5 ps. The contribution of the slow tail was also very small. The electronic component of effective third-order optical nonlinear susceptibility of the neat film of squarylium dye had value of as high as ca. 3.6 x 10-8 esu.

Roles of microtubules and cellulose microfibril assembly in the localization of secondary-cell-wall deposition in developing tracheary elements.

PubMed

Roberts, A W; Frost, A O; Roberts, E M; Haigler, C H

2004-12-01

The roles of cellulose microfibrils and cortical microtubules in establishing and maintaining the pattern of secondary-cell-wall deposition in tracheary elements were investigated with direct dyes to inhibit cellulose microfibril assembly and amiprophosmethyl to inhibit microtubule polymerization. When direct dyes were added to xylogenic cultures of Zinnia elegans L. mesophyll cells just before the onset of differentiation, the secondary cell wall was initially secreted as bands composed of discrete masses of stained material, consistent with immobilized sites of cellulose synthesis. The masses coalesced, forming truncated, sinuous or smeared thickenings, as secondary cell wall deposition continued. The absence of ordered cellulose microfibrils was confirmed by polarization microscopy and a lack of fluorescence dichroism as determined by laser scanning microscopy. Indirect immunofluorescence showed that cortical microtubules initially subtended the masses of dye-altered secondary cell wall material but soon became disorganized and disappeared. Although most of the secondary cell wall was deposited in the absence of subtending cortical microtubules in dye-treated cells, secretion remained confined to discrete regions of the plasma membrane. Examination of non-dye-treated cultures following application of microtubule inhibitors during various stages of secondary-cell-wall deposition revealed that the pattern became fixed at an early stage such that deposition remained localized in the absence of cortical microtubules. These observations indicate that cortical microtubules are required to establish, but not to maintain, patterned secondary-cell-wall deposition. Furthermore, cellulose microfibrils play a role in maintaining microtubule arrays and the integrity of the secondary-cell-wall bands during deposition.

Fast, Highly-Sensitive, and Wide-Dynamic-Range Interdigitated Capacitor Glucose Biosensor Using Solvatochromic Dye-Containing Sensing Membrane

PubMed Central

Khan, Md. Rajibur Rahaman; Khalilian, Alireza; Kang, Shin-Won

2016-01-01

In this paper, we proposed an interdigitated capacitor (IDC)-based glucose biosensor to measure different concentrations of glucose from 1 μM to 1 M. We studied four different types of solvatochromic dyes: Auramine O, Nile red, Rhodamine B, and Reichardt’s dye (R-dye). These dyes were individually incorporated into a polymer [polyvinyl chloride (PVC)] and N,N-Dimethylacetamide (DMAC) solution to make the respective dielectric/sensing materials. To the best of our knowledge, we report for the first time an IDC glucose biosensing system utilizing a solvatochromic-dye-containing sensing membrane. These four dielectric or sensing materials were individually placed into the interdigitated electrode (IDE) by spin coating to make four IDC glucose biosensing elements. The proposed IDC glucose biosensor has a high sensing ability over a wide dynamic range and its sensitivity was about 23.32 mV/decade. It also has fast response and recovery times of approximately 7 s and 5 s, respectively, excellent reproducibility with a standard deviation of approximately 0.023, highly stable sensing performance, and real-time monitoring capabilities. The proposed IDC glucose biosensor was compared with an IDC, potentiometric, FET, and fiber-optic glucose sensor with respect to response time, dynamic range width, sensitivity, and linearity. We observed that the designed IDC glucose biosensor offered excellent performance. PMID:26907291

Fast, Highly-Sensitive, and Wide-Dynamic-Range Interdigitated Capacitor Glucose Biosensor Using Solvatochromic Dye-Containing Sensing Membrane.

PubMed

Khan, Md Rajibur Rahaman; Khalilian, Alireza; Kang, Shin-Won

2016-02-20

In this paper, we proposed an interdigitated capacitor (IDC)-based glucose biosensor to measure different concentrations of glucose from 1 μM to 1 M. We studied four different types of solvatochromic dyes: Auramine O, Nile red, Rhodamine B, and Reichardt's dye (R-dye). These dyes were individually incorporated into a polymer [polyvinyl chloride (PVC)] and N,N-Dimethylacetamide (DMAC) solution to make the respective dielectric/sensing materials. To the best of our knowledge, we report for the first time an IDC glucose biosensing system utilizing a solvatochromic-dye-containing sensing membrane. These four dielectric or sensing materials were individually placed into the interdigitated electrode (IDE) by spin coating to make four IDC glucose biosensing elements. The proposed IDC glucose biosensor has a high sensing ability over a wide dynamic range and its sensitivity was about 23.32 mV/decade. It also has fast response and recovery times of approximately 7 s and 5 s, respectively, excellent reproducibility with a standard deviation of approximately 0.023, highly stable sensing performance, and real-time monitoring capabilities. The proposed IDC glucose biosensor was compared with an IDC, potentiometric, FET, and fiber-optic glucose sensor with respect to response time, dynamic range width, sensitivity, and linearity. We observed that the designed IDC glucose biosensor offered excellent performance.

Effect of viscosity on food transport and swallow initiation during eating of two-phase food in normal young adults: a pilot study.

PubMed

Matsuo, Koichiro; Kawase, Soichiro; Wakimoto, Nina; Iwatani, Kazuhiro; Masuda, Yuji; Ogasawara, Tadashi

2013-03-01

When eating food containing both liquid and solid phases (two-phase food), the liquid component frequently enters the hypopharynx before swallowing, which may increase the risk of aspiration. We therefore tested whether preswallow bolus transport and swallow initiation would change as the viscosity of two-phase food was increased. Fiberoptic endoscopy was recorded while 18 adult subjects ate 5 g of steamed rice with 3 ml of blue-dye water. Liquid viscosity was set at four levels by adding a thickening agent (0, 1, 2, and 4 wt%, respectively). We measured the timing of the leading edge of the food reaching the base of the epiglottis, as well as the location of the leading edge at swallow initiation. As viscosity increased, the leading edge of the food reached the epiglottis significantly later during chewing and was higher in the pharynx at swallow onset. The time after the leading edge reached the epiglottis did not vary among the viscosities of the two-phase food. This study found that the initial viscosity of two-phase food significantly altered oropharyngeal bolus flow and the timing of swallow initiation. Accordingly, increased two-phase food viscosity may delay food entry into the pharynx and be of use in dysphagic diets.

Adsorption of anionic and cationic dyes on activated carbon from aqueous solutions: equilibrium and kinetics.

PubMed

Rodríguez, Araceli; García, Juan; Ovejero, Gabriel; Mestanza, María

2009-12-30

Activated carbon was utilized as adsorbent to remove anionic dye, Orange II (OII), and cationic dye, Methylene blue (MB), from aqueous solutions by adsorption. Batch experiments were conducted to study the effects of temperature (30-65 degrees C), initial concentration of adsorbate (300-500 mg L(-1)) and pH (3.0-9.0) on dyes adsorption. Equilibrium adsorption isotherms and kinetics were investigated. The equilibrium experimental data were analyzed by the Langmuir, Freundlich, Toth and Redlich-Peterson models. The kinetic data obtained with different carbon mass were analyzed using a pseudo-first order, pseudo-second order, intraparticle diffusion, Bangham and Chien-Clayton equations. The best results were achieved with the Langmuir isotherm equilibrium model and with the pseudo-second order kinetic model. The activated carbon was found to be very effective as adsorbent for MB and OII from aqueous solutions.

Improving the Performance of Gold-Nanoparticle-Doped Solid-State Dye Laser Using Thermal Conversion Effect

NASA Astrophysics Data System (ADS)

An, N. T. M.; Lien, N. T. H.; Hoang, N. D.; Hoa, D. Q.

2018-04-01

Energy transfer between spherical gold nanoparticles with size of more than 15 nm and molecules of organic dye 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4 H-pyran (DCM) has been studied. Such radiative energy transfer led to high local temperature, giving rise to a bleaching effect that resulted in rapid degradation of the laser medium. Gold nanoparticles were dispersed at concentrations from 5 × 109 particles/mL to 5 × 1010 particles/mL in DCM polymethylmethacrylate polymer using a radical polymerization process with 2,2'-azobis(isobutyronitrile) (AIBN) as initiator. Using the fast thermoelectric cooling method, the laser medium stability was significantly improved. The output stability of a distributed feedback dye laser pumped by second-harmonic generation from a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser was investigated. Moreover, bidirectional energy transfer between gold nanoparticles and dye molecules was observed.

Summary and interpretation of dye-tracer tests to investigate the hydraulic connection of fractures at a ridge-and-valley-wall site near Fishtrap Lake, Pike County, Kentucky

USGS Publications Warehouse

Taylor, Charles J.

1994-01-01

Dye-tracer tests were done during 1985-92 to investigate the hydraulic connection between fractures in Pennsylvanian coal-bearing strata at a ridge-and-valley-wall site near Fishtrap Lake, Pike County, Ky. Fluorescent dye was injected into a core hole penetrating near-surface and mining-induced fractures near the crest of the ridge. The rate and direction of migration of dye in the subsurface were determined by measuring the relative concentration of dye in water samples collected from piezometers completed in conductive fracture zones and fractured coal beds at various stratigraphic horizons within the ridge. Dye-concentration data and water-level measurements for each piezometer were plotted as curves on dye-recovery hydrographs. The dye-recovery hydrographs were used to evaluate trends in the fluctuation of dye concentrations and hydraulic heads in order to identify geologic and hydrologic factors affecting the subsurface transport of dye. The principal factors affecting the transport of dye in the subsurface hydrologic system were determined to be (1) the distribution, interconnection, and hydraulic properties of fractures; (2) hydraulic-head conditions in the near-fracture zone at the time of dye injection; and (3) subsequent short- and long-term fluctuations in recharge to the hydrologic system. In most of the dye-tracer tests, dye-recovery hydrographs are characterized by complex, multipeaked dye-concentration curves that are indicative of a splitting of dye flow as ground water moved through fractures. Intermittent dye pulses (distinct upward spikes in dye concentration) mark the arrivals of dye-labeled water to piezometers by way of discrete fracture-controlled flow paths that vary in length, complexity, and hydraulic conductivity. Dye injections made during relatively high- or increasinghead conditions resulted in rapid transport of dye (within several days or weeks) from near-surf ace fractures to piezometers. Injections made during relatively low- or decreasing-head conditions resulted in dye being trapped in hydraulically dead zones in water-depleted fractures. Residual dye was remobilized from storage and transported (over periods ranging from several months to about 2 years) by increased recharge to the hydrologic system. Subsequent fluctuations in hydraulic gradients, resulting from increases or decreases in recharge to the hydrologic system, acted to speed or slow the transport of dye along the fracture-controlled flow paths. The dye-tracer tests also demonstrated that mining-related disturbances significantly altered the natural fracture-controlled flow paths of the hydrologic system over time. An abandoned underground mine and subsidence-related surface cracks extend to within 250 ft of the principal dye-injection core hole. Results from two of the dye-tracer tests at the site indicate that the annular seal in the core hole was breached by subsurface propagation of the mining-induced fractures. This propagation of fractures resulted in hydraulic short-circuiting between the dye-injection zone in the core hole and two lower piezometer zones, and a partial disruption of the hydraulic connection between the injection core hole and downgradient piezometers on the ridge crest and valley wall. In addition, injected dye was detected in piezometers monitoring a flooded part of the abandoned underground mine. Dye was apparently transported into the mine through a hydraulic connection between the injection core hole and subsidence-related fractures.

Short Time Exposure (STE) test in conjunction with Bovine Corneal Opacity and Permeability (BCOP) assay including histopathology to evaluate correspondence with the Globally Harmonized System (GHS) eye irritation classification of textile dyes.

PubMed

Oliveira, Gisele Augusto Rodrigues; Ducas, Rafael do Nascimento; Teixeira, Gabriel Campos; Batista, Aline Carvalho; Oliveira, Danielle Palma; Valadares, Marize Campos

2015-09-01

Eye irritation evaluation is mandatory for predicting health risks in consumers exposed to textile dyes. The two dyes, Reactive Orange 16 (RO16) and Reactive Green 19 (RG19) are classified as Category 2A (irritating to eyes) based on the UN Globally Harmonized System for classification (UN GHS), according to the Draize test. On the other hand, animal welfare considerations and the enforcement of a new regulation in the EU are drawing much attention in reducing or replacing animal experiments with alternative methods. This study evaluated the eye irritation of the two dyes RO16 and RG19 by combining the Short Time Exposure (STE) and the Bovine Corneal Opacity and Permeability (BCOP) assays and then comparing them with in vivo data from the GHS classification. The STE test (first level screening) categorized both dyes as GHS Category 1 (severe irritant). In the BCOP, dye RG19 was also classified as GHS Category 1 while dye RO16 was classified as GHS no prediction can be made. Both dyes caused damage to the corneal tissue as confirmed by histopathological analysis. Our findings demonstrated that the STE test did not contribute to arriving at a better conclusion about the eye irritation potential of the dyes when used in conjunction with the BCOP test. Adding the histopathology to the BCOP test could be an appropriate tool for a more meaningful prediction of the eye irritation potential of dyes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ultrafast photodynamics of the indoline dye D149 adsorbed to porous ZnO in dye-sensitized solar cells.

PubMed

Rohwer, Egmont; Richter, Christoph; Heming, Nadine; Strauch, Kerstin; Litwinski, Christian; Nyokong, Tebello; Schlettwein, Derck; Schwoerer, Heinrich

2013-01-14

We investigate the ultrafast dynamics of the photoinduced electron transfer between surface-adsorbed indoline D149 dye and porous ZnO as used in the working electrodes of dye-sensitized solar cells. Transient absorption spectroscopy was conducted on the dye in solution, on solid state samples and for the latter in contact to a I(-)/I(3)(-) redox electrolyte typical for dye-sensitized solar cells to elucidate the effect of each component in the observed dynamics. D149 in a solution of 1:1 acetonitrile and tert-butyl alcohol shows excited-state lifetimes of 300±50 ps. This signature is severely quenched when D149 is adsorbed to ZnO, with the fastest component of the decay trace measured at 150±20 fs due to the charge-transfer mechanism. Absorption bands of the oxidized dye molecule were investigated to determine regeneration times which are in excess of 1 ns. The addition of the redox electrolyte to the system results in faster regeneration times, of the order of 1 ns. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assessment of Acridine Orange and SYTO 16 for in vivo imaging of the peritoneal tissues in mice

PubMed Central

Udovich, Joshua Anthony; Besselsen, David G.; Gmitro, Arthur F.

2009-01-01

The effect of peritoneal injection of Acridine Orange (AO) and SYTO 16 in mice was investigated. Images of peritoneal tissues stained with these dyes and obtained through a confocal microendoscope are presented. Seventy-five Balb/c mice were split into five groups and given peritoneal injections of dye or saline. The proportions of negative outcomes in each group were compared using confidence intervals and the Fisher's exact statistical test. A statistically significant increase in adverse events due to dye injection was not observed.These data provide an initial investigation into the safety of AO and SYTO 16 for in vivo imaging. PMID:19397741

Design of Far-Red Sensitizing Squaraine Dyes Aiming Towards the Fine Tuning of Dye Molecular Structure.

PubMed

Morimoto, Takuya; Fujikawa, Naotaka; Ogomi, Yuhei; Pandey, Shyam S; Ma, Tingli; Hayase, Shuzi

2016-04-01

Model squaraine dyes having sharp and narrow absorptions mainly in the far-red wavelength region has been logically designed, synthesized and used for their application as sensitizer in the dyesensitized solar cells (DSSC). In order to have fine control on energetics, dyes having same mother core and alkyl chain length varying only in molecular symmetry and position of substituent were designed. It has been found that even keeping all other structural factor constant, only positional variation of substituent leads to not only in the variation of energetics by 0.1 eV but affects the photovoltaic characteristics also. Optimum concentration of dye de-aggregating agent was found to be 100 times with respect to the sensitizing dye concentration. Amongst dyes utilized in this work best performance was obtained for unsymmetrical dye SQ-40 giving a photoconversion efficiency of 4.01% under simulated solar irradiation at global AM 1.5.

Higher Performance of DSSC with Dyes from Cladophora sp. as Mixed Cosensitizer through Synergistic Effect

PubMed Central

Haji Manaf, Noramaliyana; Tennakoon, Kushan; Chandrakanthi, R. L. N.; Lim, Linda Biaw Leng; Bandara, J. M. R. Sarath; Ekanayake, Piyasiri

2015-01-01

Chlorophyll and xanthophyll dyes extracted from a single source of filamentous freshwater green algae (Cladophora sp.) were used to sensitize dye sensitized solar cells and their performances were investigated. A more positive interaction is expected as the derived dyes come from a single natural source because they work mutually in nature. Cell sensitized with mixed chlorophyll and xanthophyll showed synergistic activity with improved cell performance of 1.5- to 2-fold higher than that sensitized with any individual dye. The effect of temperature and the stability of these dyes were also investigated. Xanthophyll dye was found to be more stable compared to chlorophyll that is attributed in the ability of xanthophyll to dissipate extra energy via reversible structural changes. Mixing the dyes resulted to an increase in effective electron life time and reduced the process of electron recombination during solar cell operation, hence exhibiting a synergistic effect. PMID:25688266

Higher Performance of DSSC with Dyes from Cladophora sp. as Mixed Cosensitizer through Synergistic Effect.

PubMed

Lim, Andery; Haji Manaf, Noramaliyana; Tennakoon, Kushan; Chandrakanthi, R L N; Lim, Linda Biaw Leng; Bandara, J M R Sarath; Ekanayake, Piyasiri

2015-01-01

Chlorophyll and xanthophyll dyes extracted from a single source of filamentous freshwater green algae (Cladophora sp.) were used to sensitize dye sensitized solar cells and their performances were investigated. A more positive interaction is expected as the derived dyes come from a single natural source because they work mutually in nature. Cell sensitized with mixed chlorophyll and xanthophyll showed synergistic activity with improved cell performance of 1.5- to 2-fold higher than that sensitized with any individual dye. The effect of temperature and the stability of these dyes were also investigated. Xanthophyll dye was found to be more stable compared to chlorophyll that is attributed in the ability of xanthophyll to dissipate extra energy via reversible structural changes. Mixing the dyes resulted to an increase in effective electron life time and reduced the process of electron recombination during solar cell operation, hence exhibiting a synergistic effect.

Decolorization of sulfonated azo dye Metanil Yellow by newly isolated bacterial strains: Bacillus sp. strain AK1 and Lysinibacillus sp. strain AK2.

PubMed

Anjaneya, O; Souche, S Yogesh; Santoshkumar, M; Karegoudar, T B

2011-06-15

Two different bacterial strains capable of decolorizing a highly water soluble azo dye Metanil Yellow were isolated from dye contaminated soil sample collected from Atul Dyeing Industry, Bellary, India. The individual bacterial strains Bacillus sp. AK1 and Lysinibacillus sp. AK2 decolorized Metanil Yellow (200 mg L(-1)) completely within 27 and 12h respectively. Various parameters like pH, temperature, NaCl and initial dye concentrations were optimized to develop an economically feasible decolorization process. The maximum concentration of Metanil Yellow (1000 mg L(-1)) was decolorized by strains AK2 and AK1 within 78 and 84 h respectively. These strains could decolorize Metanil Yellow over a broad pH range 5.5-9.0; the optimum pH was 7.2. The decolorization of Metanil Yellow was most efficient at 40°C and confirmed by UV-visible spectroscopy, TLC, HPLC and GC/MS analysis. Further, both the strains showed the involvement of azoreductase in the decolorization process. Phytotoxicity studies of catabolic products of Metanil Yellow on the seeds of chick pea and pigeon pea revealed much reduction in the toxicity of metabolites as compared to the parent dye. These results indicating the effectiveness of strains AK1 and AK2 for the treatment of textile effluents containing azo dyes. Copyright © 2011 Elsevier B.V. All rights reserved.

Personal use of hair dyes and the risk of bladder cancer: results of a meta-analysis.

PubMed Central

Huncharek, Michael; Kupelnick, Bruce

2005-01-01

OBJECTIVE: This study examined the methodology of observational studies that explored an association between personal use of hair dye products and the risk of bladder cancer. METHODS: Data were pooled from epidemiological studies using a general variance-based meta-analytic method that employed confidence intervals. The outcome of interest was a summary relative risk (RRs) reflecting the risk of bladder cancer development associated with use of hair dye products vs. non-use. Sensitivity analyses were performed to explain any observed statistical heterogeneity and to explore the influence of specific study characteristics of the summary estimate of effect. RESULTS: Initially combining homogenous data from six case-control and one cohort study yielded a non-significant RR of 1.01 (0.92, 1.11), suggesting no association between hair dye use and bladder cancer development. Sensitivity analyses examining the influence of hair dye type, color, and study design on this suspected association showed that uncontrolled confounding and design limitations contributed to a spurious non-significant summary RR. The sensitivity analyses yielded statistically significant RRs ranging from 1.22 (1.11, 1.51) to 1.50 (1.30, 1.98), indicating that personal use of hair dye products increases bladder cancer risk by 22% to 50% vs. non-use. CONCLUSION: The available epidemiological data suggest an association between personal use of hair dye products and increased risk of bladder cancer. PMID:15736329

Plasma dye coating as straightforward and widely applicable procedure for dye immobilization on polymeric materials.

PubMed

De Smet, Lieselot; Vancoillie, Gertjan; Minshall, Peter; Lava, Kathleen; Steyaert, Iline; Schoolaert, Ella; Van De Walle, Elke; Dubruel, Peter; De Clerck, Karen; Hoogenboom, Richard

2018-03-16

Here, we introduce a novel concept for the fabrication of colored materials with significantly reduced dye leaching through covalent immobilization of the desired dye using plasma-generated surface radicals. This plasma dye coating (PDC) procedure immobilizes a pre-adsorbed layer of a dye functionalized with a radical sensitive group on the surface through radical addition caused by a short plasma treatment. The non-specific nature of the plasma-generated surface radicals allows for a wide variety of dyes including azobenzenes and sulfonphthaleins, functionalized with radical sensitive groups to avoid significant dye degradation, to be combined with various materials including PP, PE, PA6, cellulose, and PTFE. The wide applicability, low consumption of dye, relatively short procedure time, and the possibility of continuous PDC using an atmospheric plasma reactor make this procedure economically interesting for various applications ranging from simple coloring of a material to the fabrication of chromic sensor fabrics as demonstrated by preparing a range of halochromic materials.

Data collection for a time-of-travel and dispersion study on the Coosa River near Childersburg, Alabama

USGS Publications Warehouse

Gardner, R.A.

1985-01-01

Approximately 2,300 dye-tracer samples were collected and analyzed during a 5-day time-of-travel study on a 23-mile reach of the Coosa River between Logan Martin and Lay dams near Childersburg, Alabama, October 27 to 31, 1984. Rhodamine WT was used as the tracer-dye. Unsteady flow conditions prevailed in the study reach. The rate of movement of the dye cloud between sampling cross sections ranged from 0.15 to 1.36 feet per second. The average rate of movement of the dye cloud between the injection cross section and the downstream sampling cross section was 0.42 foot per second. (USGS)

A viscosity sensitive fluorescent dye for real-time monitoring of mitochondria transport in neurons.

PubMed

Baek, Yeonju; Park, Sang Jun; Zhou, Xin; Kim, Gyungmi; Kim, Hwan Myung; Yoon, Juyoung

2016-12-15

We present here a viscosity sensitive fluorescent dye, namely thiophene dihemicyanine (TDHC), that enables the specific staining of mitochondria. In comparison to the common mitochondria tracker (Mitotracker Deep Red, MTDR), this dye demonstrated its unique ability for robust staining of mitochondria with high photostability and ultrahigh signal-to-noise ratio (SNR). Moreover, TDHC also showed high sensitivity towards mitochondria membrane potential (ΔΨm) and intramitochondria viscosity change. Consequently, this dye was utilized in real-time monitoring of mitochondria transport in primary cortical neurons. Finally, the Two-Photon Microscopy (TPM) imaging ability of TDHC was also demonstrated. Copyright © 2016 Elsevier B.V. All rights reserved.

A square-wave adsorptive stripping voltammetric method for determination of fast green dye.

PubMed

Al-Ghamdi, Ali F

2009-01-01

Square-wave adsorptive stripping voltammetric (SW-AdSV) determinations of trace concentrations of the coloring agent fast green were described. The analytical methodology used was based on the adsorptive preconcentration of the dye on the hanging mercury drop electrode, and then a negative sweep was initiated. In pH 10 carbonate supporting electrolyte, fast green gave a well-defined and sensitive SW-AdSV peak at -1220 mV. The electroanalytical determination of this dye was found to be optimized in carbonate buffer (pH 10) with the following experimental conditions: accumulation time (120 s); accumulation potential (-0.8 V); scan rate (800 mV/s); pulse amplitude (90 mV); frequency (90 Hz); surface area of the working electrode (0.6 mm2); and the convection rate (2000 rpm). Under these optimized conditions, the AdSV peak current was proportional over the concentration range 2 x 10(-8) -6 x 10(-7) M (r = 0.999), with an LOD of 1.63 x 10(-10) M (0.132 ppb). This analytical approach possessed more enhanced sensitivity than conventional chromatography or spectrophotometry, and was simple and quick. The precision of the method in terms of RSD was 0.17%, whereas the accuracy was evaluated via the mean recovery of 99.6%. Possible interferences by several substances usually present as food additive azo dyes (E110, E102, E123, and E129), natural and artificial sweeteners, and antioxidants were also investigated. Applicability of the developed electroanalysis method was illustrated via the determination of fast green in ice cream and soft drink samples.

Ultrafast Flame Annealing of TiO2 Paste for Fabricating Dye-Sensitized and Perovskite Solar Cells with Enhanced Efficiency.

PubMed

Kim, Jung Kyu; Chai, Sung Uk; Cho, Yoonjun; Cai, Lili; Kim, Sung June; Park, Sangwook; Park, Jong Hyeok; Zheng, Xiaolin

2017-11-01

Mesoporous TiO 2 nanoparticle (NP) films are broadly used as electrodes in photoelectrochemical cells, dye-sensitized solar cells (DSSCs), and perovskite solar cells (PSCs). State-of-the-art mesoporous TiO 2 NP films for these solar cells are fabricated by annealing TiO 2 paste-coated fluorine-doped tin oxide glass in a box furnace at 500 °C for ≈30 min. Here, the use of a nontraditional reactor, i.e., flame, is reported for the high throughput and ultrafast annealing of TiO 2 paste (≈1 min). This flame-annealing method, compared to conventional furnace annealing, exhibits three distinct benefits. First, flame removes polymeric binders in the initial TiO 2 paste more completely because of its high temperature (≈1000 °C). Second, flame induces strong interconnections between TiO 2 nanoparticles without affecting the underlying transparent conducting oxide substrate. Third, the flame-induced carbothermic reduction on the TiO 2 surface facilitates charge injection from the dye/perovskite to TiO 2 . Consequently, when the flame-annealed mesoporous TiO 2 film is used to fabricate DSSCs and PSCs, both exhibit enhanced charge transport and higher power conversion efficiencies than those fabricated using furnace-annealed TiO 2 films. Finally, when the ultrafast flame-annealing method is combined with a fast dye-coating method to fabricate DSSC devices, its total fabrication time is reduced from over 3 h to ≈10 min. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of degradation of Reactive Black 5 (RB5) and electricity generation in solar photocatalytic fuel cell system.

PubMed

Khalik, Wan Fadhilah; Ho, Li-Ngee; Ong, Soon-An; Voon, Chun-Hong; Wong, Yee-Shian; Yusoff, NikAthirah; Lee, Sin-Li; Yusuf, Sara Yasina

2017-10-01

The photocatalytic fuel cell (PFC) system was developed in order to study the effect of several operating parameters in degradation of Reactive Black 5 (RB5) and its electricity generation. Light irradiation, initial dye concentration, aeration, pH and cathode electrode are the operating parameters that might give contribution in the efficiency of PFC system. The degradation of RB5 depends on the presence of light irradiation and solar light gives better performance to degrade the azo dye. The azo dye with low initial concentration decolorizes faster compared to higher initial concentration and presence of aeration in PFC system would enhance its performance. Reactive Black 5 rapidly decreased at higher pH due to the higher amount of OH generated at higher pH and Pt-loaded carbon (Pt/C) was more suitable to be used as cathode in PFC system compared to Cu foil and Fe foil. The rapid decolorization of RB5 would increase their voltage output and in addition, it would also increase their V oc , J sc and P max . The breakage of azo bond and aromatic rings was confirmed through UV-Vis spectrum and COD analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of different π-bridge configuration on bi-anchored triphenylamine and phenyl modified triphenylamine based dyes for dye sensitized solar cell (DSSC) application: A theoretical approach.

PubMed

Pounraj, P; Mohankumar, V; Pandian, M Senthil; Ramasamy, P

2018-01-01

Twenty eight bi-anchored triphenylamine (TH-1 to TH-14) and phenyl modified triphenylamine (PH-TH-1 to PH-TH-14) based metal free organic dyes are designed for DSSC application. The electronic effect of different π-bridge configurations in donor-π-bridge-acceptor (D-π-A) 2 structure was theoretically simulated and verified using density functional theory (DFT) and time dependent density functional theory (TD-DFT). The triphenylamine and phenyl modified triphenylamine groups are used as donor and cyanoacrylic acid group is used as acceptor. Thiophene and cyanovinyl groups are used as π-bridge. The ground state molecular structure was optimized by density functional theory and the electronic absorption spectra were calculated by time dependent density functional theory. The light harvesting efficiency (LHE), dye regeneration energy (ΔG reg ) and electron injection energy (ΔG inject ) are determined by computational examination. It is observed that, when the number of π-bridge increases, the band gap of the dye decreases. Also the absorption maximum and molar extinction coefficient of the dyes are increased. Theoretical result shows that the thiophene-cyanovinyl and thiophene-thiophene-cyanovinyl-cyanovinyl configurations give broader and red shifted absorption spectrum compared to other configurations. Also the results of phenyl modified triphenylamine (PH-TH) dyes clearly show better absorption and dye regeneration energy compared to TH dyes. Copyright © 2017 Elsevier Inc. All rights reserved.

Synthesis of magnetic biocomposite for efficient adsorption of azo dye from aqueous solution.

PubMed

Sivashankar, R; Sathya, A B; Krishnakumar, Uma; Sivasubramanian, V

2015-11-01

A novel magnetic biocomposite was synthesized using metal chlorides and aquatic macrophytes by co-precipitation method. The resulting product, magnetic biocomposite was characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX) and Scanning electron microscope (SEM). The adsorption performance of the magnetic biocomposite was tested with removal of Metanil Yellow dye from aqueous solution. The effect of influencing parameters such as initial dye concentration, solution pH and agitation were investigated. The equilibrium isotherm was well described by the Langmuir model with the with maximum adsorption capacity of 90.91mg/g. Adsorption kinetics experiments were carried out and the data were well fitted by a pseudo-second-order equation. The results revealed that the magnetic biocomposite could efficiently adsorb the azo dyes from aqueous solution, and the spent adsorbents could be recovered completely by magnetic separation process. Therefore, the prepared magnetic biocomposite could thus be used as promising adsorbent for the removal of azo dyes from polluted water. Copyright © 2015 Elsevier Inc. All rights reserved.

Remediation of textile dye waste water using a white-rot fungus Bjerkandera adusta through solid-state fermentation (SSF).

PubMed

Robinson, Tim; Nigam, Poonam Singh

2008-12-01

A strict screening strategy for microorganism selection was followed employing a number of white-rot fungi for the bioremediation of textile effluent, which was generated from one Ireland-based American textile industry. Finally, one fungus Bjerkandera adusta has been investigated in depth for its ability to simultaneously degrade and enrich the nutritional quality of highly coloured textile effluent-adsorbed barley husks through solid-state fermentation (SSF). Certain important parameters such as media requirements, moisture content, protein/biomass production and enzyme activities were examined in detail. A previously optimised method of dye desorption was employed to measure the extent of dye remediation through effluent decolorisation achieved as a result of fungal activity in SSF. B. adusta was capable of decolourising a considerable concentration of the synthetic dye effluent (up to 53%) with a moisture content of 80-85%. Protein enrichment of the fermented mass was achieved to the extent of 229 g/kg dry weight initial substrate used. Lignin peroxidase and laccase were found to be the two main enzymes produced during SSF of the dye-adsorbed lignocellulosic waste residue.

Optoelectronic performance comparison of new thiophene linked benzimidazole conjugates with diverse substitution patterns

NASA Astrophysics Data System (ADS)

Saltan, Gözde Murat; Dinçalp, Haluk; Kırmacı, Eser; Kıran, Merve; Zafer, Ceylan

2018-01-01

In an approach to develop efficient organic optoelectronic devices to be used in light-driven systems, a series of three thiophene linked benzimidazole conjugates were synthesized and characterized. The combination of two thiophene rings to a benzimidazole core decorated with different functional groups (such as sbnd OCH3, sbnd N(CH3)2, sbnd CF3) resulted in donor-acceptor type molecular scaffold. The effect of the electronic behavior of the substituents on the optical, electrochemical, morphological and electron/hole transporting properties of the dyes were systematically investigated. DTBI2 dye exhibited distinct absorption properties among the other studied dyes because N,N-dimethylamino group initiated intramolecular charge transfer (ICT) process in the studied solvents. In solid state, the dyes exhibit peaks extending up to 600 nm. Depending on the solvent polarities, dyes show significant wavelength changes on their fluorescence emission spectra in the excited states. Morphological parameters of the thin films spin-coated from CHCl3 solution were investigated by using AFM instrument; furthermore photovoltaic responses are reported, even though photovoltaic performances of the fabricated solar cells with different configurations are quite low.

A measurement and modeling study of temperature in living and fixed tissue during and after radiofrequency exposure.

PubMed

Bermingham, Jacqueline F; Chen, Yuen Y; McIntosh, Robert L; Wood, Andrew W

2014-04-01

Fluorescent intensity of the dye Rhodamine-B (Rho-B) decreases with increasing temperature. We show that in fresh rat brain tissue samples in a custom-made radiofrequency (RF) tissue exposure device, temperature rise due to RF radiation as measured by absorbed dye correlates well with temperature measured nearby by fiber optic probes. Estimates of rate of initial temperature rise (using both probe measurement and the dye method) accord well with estimates of local specific energy absorption rate (SAR). We also modeled the temperature characteristics of the exposure device using combined electromagnetic and finite-difference thermal modeling. Although there are some differences in the rate of cooling following cessation of RF exposure, there is reasonable agreement between modeling and both probe measurement and dye estimation of temperature. The dye method also permits measurement of regional temperature rise (due to RF). There is no clear evidence of local differential RF absorption, but further refinement of the method may be needed to fully clarify this issue. © 2014 Wiley Periodicals, Inc.

Tidal-flow, circulation, and flushing characteristics of Kings Bay, Citrus County, Florida

USGS Publications Warehouse

Hammett, K.M.; Goodwin, C.R.; Sanders, G.L.

1996-01-01

Kings Bay is an estuary on the gulf coast of peninsular Florida with a surface area of less than one square mile. It is a unique estuarine system with no significant inflowing rivers or streams. As much as 99 percent of the freshwater entering the bay originates from multiple spring vents at the bottom of the estuary. The circulation and flushing characteristics of Kings Bay were evaluated by applying SIMSYS2D, a two-dimensional numerical model. Field data were used to calibrate and verify the model. Lagrangian particle simulations were used to determine the circulation characteristics for three hydrologic conditions: low inflow, typical inflow, and low inflow with reduced friction from aquatic vegetation. Spring discharge transported the particles from Kings Bay through Crystal River and out of the model domain. Tidal effects added an oscillatory component to the particle paths. The mean particle residence time was 59 hours for low inflow with reduced friction; therefore, particle residence time is affected more by spring discharge than by bottom friction. Circulation patterns were virtually identical for the three simulated hydroloigc conditions. Simulated particles introduced in the southern part of Kings Bay traveled along the eastern side of Buzzard Island before entering Crystal River and existing the model domain. The flushing characteristics of Kings Bay for the three hydrodynamic conditions were determined by simulating the injection of conservative dye constituents. The average concentration of dye initially injected in Kings Bay decreased asymptotically because of spring discharge, and the tide caused some oscillation in the average dye concentration. Ninety-five percent of the injected dye exited Kings Bay and Crystal River with 94 hours for low inflow, 71 hours for typical inflow, and 94 hours for low inflow with reduced bottom friction. Simulation results indicate that all of the open waters of Kings Bay are flushed by the spring discharge. Reduced bottom friction has little effect on flushing.

Specific tumor labeling enhanced by polyethylene glycol linkage of near infrared dyes conjugated to a chimeric anti-carcinoembryonic antigen antibody in a nude mouse model of human pancreatic cancer

NASA Astrophysics Data System (ADS)

Maawy, Ali A.; Hiroshima, Yukihiko; Zhang, Yong; Luiken, George A.; Hoffman, Robert M.; Bouvet, Michael

2014-10-01

Labeling of metastatic tumors can aid in their staging and resection of cancer. Near infrared (NIR) dyes have been used in the clinic for tumor labeling. However, there can be a nonspecific uptake of dye by the liver, lungs, and lymph nodes, which hinders detection of metastasis. In order to overcome these problems, we have used two NIR dyes (DyLight 650 and 750) conjugated to a chimeric anti-carcinoembryonic antigen antibody to evaluate how polyethylene glycol linkage (PEGylation) can improve specific tumor labeling in a nude mouse model of human pancreatic cancer. The conjugated PEGylated and non-PEGylated DyLight 650 and 750 dyes were injected intravenously into non-tumor-bearing nude mice. Serum samples were collected at various time points in order to determine serum concentrations and elimination kinetics. Conjugated PEGylated dyes had significantly higher serum dye concentrations than non-PEGylated dyes (p=0.005 for the 650 dyes and p<0.001 for the 750 dyes). Human pancreatic tumors subcutaneously implanted into nude mice were labeled with antibody-dye conjugates and serially imaged. Labeling with conjugated PEGylated dyes resulted in significantly brighter tumors compared to the non-PEGylated dyes (p<0.001 for the 650 dyes; p=0.01 for 750 dyes). PEGylation of the NIR dyes also decreased their accumulation in lymph nodes, liver, and lung. These results demonstrate enhanced selective tumor labeling by PEGylation of dyes conjugated to a tumor-specific antibody, suggesting their future clinical use in fluorescence-guided surgery.

Preparation, Characterization of Coal Ash Adsorbent and Orthogonal Experimental Rsearch on Treating Printing and Dyeing Wastewater

NASA Astrophysics Data System (ADS)

Wang, Qingyu; He, Lingfeng; Shi, Liang; Chen, Xiaogang; Chen, Xin; Xu, Zizhen; Zhang, Yongli

2018-03-01

Using high temperature activated sodium flying ash and carboxymethyl chitosan as raw material to prepare carboxymethylchitosan wrapping fly-ash adsorbent (CWF), combined with iron-carbon micro-electrolysis treatment of simulated and actual printing and dyeing wastewater. The conditions for obtaining are from the literature: the best condition for CWF to treat simulated printing and dyeing wastewater pretreated with iron-carbon micro-electrolysis is that the mixing time is 10min, the resting time is 30 min, pH=6, and the adsorbent dosage is 0.75 g/L. The results showed that COD removal efficiency and decoloration rate were above 97 %, and turbidity removal rate was over 90 %. The optimum dyeing conditions were used to treat the dyeing wastewater. The decolorization rate was 97.30 %, the removal efficiency of COD was 92.44 %, and the turbidity removal rate was 90.37 %.

Large electronic third-order optical nonlinearities of cyanine dyes measured by resonant femtosecond degenerate four-wave mixing

NASA Astrophysics Data System (ADS)

Kasatani, Kazuo

2003-01-01

Third-order optical nonlinearities of several cyanine dyes were measured under resonant conditions by the femtosecond degenerate four-wave mixing (DFWM) technique. Temporal profiles of the DFWM signal were measured with a time resolution of 0.3 ps, and were found to consist of at least two components, the coherent instantaneous nonlinear response and the delayed response with a decay time constant of several hundred picoseconds. The latter can be attributed to molecular rotational relaxation of these dyes. The values of electronic component of the optical nonlinear susceptibility, χ e xxxx (3), for these dyes were ≈2×10 -12 esu at the very low concentration of 1×10 -5 mol dm -3. The electronic component of molecular hyperpolarizability, γe, was calculated to be ≈1×10 -28 esu for each dye.

Eragrostis plana Nees as a novel eco-friendly adsorbent for removal of crystal violet from aqueous solutions.

PubMed

Filho, Augusto Cezar D; Mazzocato, Ana C; Dotto, Guilherme L; Thue, Pascal S; Pavan, Flávio A

2017-08-01

Eragrostis plana Nees (EPN) was used as new and eco-friendly adsorbent for the removal of crystal violet dye (CV) from aqueous solution. Specific surface area (BET), scanning electron microscopy (SEM), infrared spectroscopy (ATR-FTIR), point of zero charge (pH PZC ), and modified Boehm titration method were used to characterize the EPN material. The effects of initial pH of solution, adsorbent mass, contact time and initial dye concentration, and temperature were studied in batch adsorption mode. Kinetic data were evaluated by pseudo-first-order and pseudo-second-order models. The result exhibited that pseudo-second-order model well described the adsorption kinetics of CV onto EPN. Langmuir, Freundlich, and Sips isotherm models were used for analysis of the isothermal data. The equilibrium data of adsorption of CV onto EPN was better fitted with the Sips isotherm. Based on the Sips isotherm model, the maximum adsorption capacity was 76.20 ± 1.20 mg g -1 at 333 K. A high desorption of CV from EPN was obtained using 1.00 mol L -1 of CH 3 COOH as eluent. The thermodynamic data indicated that the adsorption was spontaneous, endothermic, and physical process. EPN can be used as alternative adsorbent to remove CV from aqueous solution.

Determination of the orientation of fluorescent labels relative to myosin S1 in solution from time-resolved fluorescence anisotropy experiments

NASA Astrophysics Data System (ADS)

van der Heide, Uulke A.; Gerritsen, Hans C.; Trayer, Ian P.; Levine, Yehudi K.

1992-04-01

The time-resolved fluorescence anisotropy of myosin S1 covalently labeled with Eosin-5- maleimide and 1,5-I-AEDANS was measured in solution. Each probe was specifically attached at one SH-group on the S1. The two most reactive SH sites on the heavy chain of the myosin S1 were used. The fluorescence anisotropy was measured at different excitation wavelengths. In this way, several absorption moments were utilized, each having a distinct orientation in the frame of the dye. The orientations of the transition moments in the dyes were determined in a separate experiment using an angle resolved fluorescence depolarization experiment on dyes embedded in stretched matrices of PVA polymers. The anisotropy decay curves exhibit fast (<3 ns) and slow (> 100 ns) components. The slow decay components reflect the motion of the large protein molecules. The fast anisotropy decay are attributed to a fast, but restricted, motion of the bound dye relative to the protein as experiments on free dyes in solution reveal subnanosecond anisotropy decays. The anisotropy decays have been analyzed in terms of a model which describes the restricted motion of the dye molecule relative to the protein and the overall rotation of the dye-protein complex in solution. An important element in the model is the incorporation of the orientational distribution of the dye relative to the protein. The observed anisotropy decays were analyzed using a global target approach in which the experimental data obtained at different excitation wavelengths are fitted simultaneously to the theoretical model. It is important to note that the orientational distribution of the dye relative to the protein, as well as the rotational correlation times of the motions for a dye attached to a given binding site, are independent of the excitation wavelength used. This leads to a reduction in the number of independent parameters optimized by the nonlinear least squares procedure. The orientational distribution of the dye relative to the protein obtained in this way is particularly useful for the interpretation of fluorescence depolarization data obtained from labeled muscle fibers. Indeed, knowledge of the distribution function of a dye attached to a binding site of the S1 protein is a prerequisite for a probe-independent determination of the orientational distribution of the S1 proteins themselves in the muscle fiber.

Pigments for natural dye-sensitized solar cells from in vitro grown shoot cultures

NASA Astrophysics Data System (ADS)

Di Bari, Chiara; Forni, Cinzia; Di Carlo, Aldo; Barrajón-Catalán, Enrique; Micol, Vicente; Teoli, Federico; Nota, Paolo; Matteocci, Fabio; Frattarelli, Andrea; Caboni, Emilia; Lucioli, Simona

2017-04-01

In vitro grown shoots cultures (Prunus salicina × Prunus persica), elicited by methyl jasmonate (MJ), are reported here for the first time to prepare a natural dye for dye-sensitized solar cells (DSSC). Redox properties of the dye, its photostability, and light absorption properties suggested it as a candidate as natural photosensitizers for TiO2 photoelectrodes. Redox properties of the dye influence the DSSC production of photocurrent, thus three antioxidant assays were performed in order to characterize the antioxidant potential of this dye. The dye exhibited a high antioxidant activity in all the assays performed. Photostability assay revealed that the dye was quite stable to light. The power conversion efficiency that we obtained (0.53%) was comparable to the data by other authors with anthocyanins-based dyes from in vivo grown plants. Finally, we compared the dye with the partially purified one as photosensitizer in DSSC. The results indicated that the raw pigment from in vitro shoot cultures of P. salicina × P. persica elicited with MJ can be proposed without the needing of any other chemicals, thermal or purification process, or pH adjustments, as a dye for natural sensitized solar cells.

The development of CotA mediator cocktail system for dyes decolorization.

PubMed

Luo, S; Xie, T; Liu, Z; Sun, F; Wang, G

2018-05-01

The increasing use of dyes leads to serious environmental concerns, it is significant to explore eco-friendly and economic approaches for dye decolorization. This study aimed to develop mediator cocktail (AS and ABTS) for enhancing the capability of laccase-mediator system in the removal of dyes. By mediator screening, the mediators of ABTS and AS (ABTS, 2, 2'-azino-bis-(3-ethylbenzothiazo-thiazoline-6-sulphonic acid); AS, acetosyringone) were combined for dyes decolorization. The Box-Behnken Design and response surface analysis was performed to optimize experiment conditions. Comparing the CotA-ABTS-AS cocktail system with CotA-single mediator system showed that the coupling of ABTS and AS could increase the decolorization rate 15 times higher, save a third of the cost and shorten the reaction time by 50%. In addition, our studies revealed that sequential oxidation may occur in CotA-ABTS-AS system. Compared with CotA laccase-single mediator system, the CotA-ABTS-AS cocktail system showed advantages including higher efficiency, lower cost and shorter reaction time. This was the first report on the dyes decolorization by laccase mediator cocktail system. These results paved the curb for the application of laccase mediator system in various industrial processes. © 2018 The Society for Applied Microbiology.

Synthesis of highly stable cyanine-dye-doped silica nanoparticle for biological applications

NASA Astrophysics Data System (ADS)

Lian, Ying; Ding, Long-Jiang; Zhang, Wei; Zhang, Xiao-ai; Zhang, Ying-Lu; Lin, Zhen-zhen; Wang, Xu-dong

2018-07-01

Cyanine dyes are widely used in biological labeling and imaging because of their narrow near infrared emission, good brightness and high flexibility in functionalization, which not only enables multiplex analysis and multi-color imaging, but also greatly reduces autofluorescence from biological matter and increases signal-to-noise ratio. Unfortunately, their poor chemical- and photo-stability strongly limits their applications. The incorporation of cyanine dyes in silica nanoparticles provides a solution to the problem. On one hand, the incorporation of cyanine dyes in silica matrix can enhance their chemical- and photo-stability and increase brightness of the nanomaterials. On the other hand, silica matrix provides an optimized condition to host the dye, which helps to maintain their fluorescent properties during application. In addition, the well-established silane technique provides numerous functionalities for diverse applications. However, commercially available cyanine dyes are not very stable at high alkaline conditions, which will gradually lose their fluorescence over time. Our results showed that cyanine dyes are very vulnerable in the reverse micelle system, in which they will lose their fluorescence in less than half an hour. The existence of surfactant could greatly promote degradation of cyanine dyes. Fluorescent silica nanoparticles cannot be obtained at the high alkaline condition with the existence of surfactant. In contrast, the cyanine dyes are relatively stable in Stöber media. Owing to the fast formation of silica particles in Stöber media, the exposure time of cyanine dye in alkaline solution was greatly reduced, and highly fluorescent particles with good morphology and size distribution could be obtained via Stöber approach. However, the increasing water content in the Stöber could reduce the stability of cyanine dyes, which should be avoided. This research here provides a clear guidance on how to successfully synthesize cyanine dye-doped silica nanoparticles with good morphology, size distribution, stability and brightness.

Biosorption of Methylene Blue by De-Oiled Algal Biomass: Equilibrium, Kinetics and Artificial Neural Network Modelling

PubMed Central

Maurya, Rahulkumar; Ghosh, Tonmoy; Paliwal, Chetan; Shrivastav, Anupama; Chokshi, Kaumeel; Pancha, Imran; Ghosh, Arup; Mishra, Sandhya

2014-01-01

The main objective of the present study is to effectively utilize the de-oiled algal biomass (DAB) to minimize the waste streams from algal biofuel by using it as an adsorbent. Methylene blue (MB) was used as a sorbate for evaluating the potential of DAB as a biosorbent. The DAB was characterized by SEM, FTIR, pHPZC, particle size, pore volume and pore diameter to understand the biosorption mechanism. The equilibrium studies were carried out by variation in different parameters, i.e., pH (2–9), temperature (293.16–323.16 K), biosorbent dosage (1–10 g L−1), contact time (0–1,440 min), agitation speed (0–150 rpm) and dye concentration (25–2,500 mg L−1). MB removal was greater than 90% in both acidic and basic pH. The optimum result of MB removal was found at 5–7 g L−1 DAB concentration. DAB removes 86% dye in 5 minutes under static conditions and nearly 100% in 24 hours when agitated at 150 rpm. The highest adsorption capacity was found 139.11 mg g−1 at 2,000 mg L−1 initial MB concentration. The process attained equilibrium in 24 hours. It is an endothermic process whose spontaneity increases with temperature. MB biosorption by DAB follows pseudo-second order kinetics. Artificial neural network (ANN) model also validates the experimental dye removal efficiency (R2 = 0.97) corresponding with theoretically predicted values. Sensitivity analysis suggests that temperature and agitation speed affect the process most with 23.62% and 21.08% influence on MB biosorption, respectively. Dye adsorption capacity of DAB in fixed bed column was 107.57 mg g−1 in preliminary study while it went up to 139.11 mg g−1 in batch studies. The probable mechanism for biosorption in this study is chemisorptions via surface active charges in the initial phase followed by physical sorption by occupying pores of DAB. PMID:25310576

Sensitization of Nanocrystalline Metal Oxides with a Phosphonate-Functionalized Perylene Diimide for Photoelectrochemical Water Oxidation with a CoOx Catalyst.

PubMed

Kirner, Joel T; Finke, Richard G

2017-08-23

A planar organic thin film composed of a perylene diimide dye (N,N'-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) with photoelectrochemically deposited cobalt oxide (CoO x ) catalyst was previously shown to photoelectrochemically oxidize water (DOI: 10.1021/am405598w). Herein, the same PMPDI dye is studied for the sensitization of different nanostructured metal oxide (nano-MO x ) films in a dye-sensitized photoelectrochemical cell architecture. Dye adsorption kinetics and saturation decreases in the order TiO 2 > SnO 2 ≫ WO 3 . Despite highest initial dye loading on TiO 2 films, photocurrent with hydroquinone (H 2 Q) sacrificial reductant in pH 7 aqueous solution is much higher on SnO 2 films, likely due to a higher driving force for charge injection into the more positive conduction band energy of SnO 2 . Dyeing conditions and SnO 2 film thickness were subsequently optimized to achieve light-harvesting efficiency >99% at the λ max of the dye, and absorbed photon-to-current efficiency of 13% with H 2 Q, a 2-fold improvement over the previous thin-film architecture. A CoO x water-oxidation catalyst was photoelectrochemically deposited, allowing for photoelectrochemical water oxidation with a faradaic efficiency of 31 ± 7%, thus demonstrating the second example of a water-oxidizing, dye-sensitized photoelectrolysis cell composed entirely of earth-abundant materials. However, deposition of CoO x always results in lower photocurrent due to enhanced recombination between catalyst and photoinjected electrons in SnO 2 , as confirmed by open-circuit photovoltage measurements. Possible future studies to enhance photoanode performance are discussed, including alternative catalyst deposition strategies or structural derivatization of the perylene dye.

Sensitization of Nanocrystalline Metal Oxides with a Phosphonate-Functionalized Perylene Diimide for Photoelectrochemical Water Oxidation with a CoO x Catalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirner, Joel T.; Finke, Richard G.

A planar organic thin film composed of a perylene diimide dye (N,N'-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) with photoelectrochemically deposited cobalt oxide (CoO x) catalyst was previously shown to photoelectrochemically oxidize water (DOI: 10.1021/am405598w). Herein, the same PMPDI dye is studied for the sensitization of different nanostructured metal oxide (nano-MO x) films in a dye-sensitized photoelectrochemical cell architecture. Dye adsorption kinetics and saturation decreases in the order TiO 2 > SnO 2 >> WO 3. Despite highest initial dye loading on TiO 2 films, photocurrent with hydroquinone (H 2Q) sacrificial reductant in pH 7 aqueous solution is much higher on SnO 2 films, likelymore » due to a higher driving force for charge injection into the more positive conduction band energy of SnO 2. Dyeing conditions and SnO 2 film thickness were subsequently optimized to achieve light-harvesting efficiency >99% at the λmax of the dye, and absorbed photon-to-current efficiency of 13% with H 2Q, a 2-fold improvement over the previous thin-film architecture. A CoO x water-oxidation catalyst was photoelectrochemically deposited, allowing for photoelectrochemical water oxidation with a faradaic efficiency of 31 ± 7%, thus demonstrating the second example of a water-oxidizing, dye-sensitized photoelectrolysis cell composed entirely of earth-abundant materials. However, deposition of CoO x always results in lower photocurrent due to enhanced recombination between catalyst and photoinjected electrons in SnO 2, as confirmed by open-circuit photovoltage measurements. Possible future studies to enhance photoanode performance are also discussed, including alternative catalyst deposition strategies or structural derivatization of the perylene dye.« less

Sensitization of Nanocrystalline Metal Oxides with a Phosphonate-Functionalized Perylene Diimide for Photoelectrochemical Water Oxidation with a CoO x Catalyst

DOE PAGES

Kirner, Joel T.; Finke, Richard G.

2017-07-20

A planar organic thin film composed of a perylene diimide dye (N,N'-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) with photoelectrochemically deposited cobalt oxide (CoO x) catalyst was previously shown to photoelectrochemically oxidize water (DOI: 10.1021/am405598w). Herein, the same PMPDI dye is studied for the sensitization of different nanostructured metal oxide (nano-MO x) films in a dye-sensitized photoelectrochemical cell architecture. Dye adsorption kinetics and saturation decreases in the order TiO 2 > SnO 2 >> WO 3. Despite highest initial dye loading on TiO 2 films, photocurrent with hydroquinone (H 2Q) sacrificial reductant in pH 7 aqueous solution is much higher on SnO 2 films, likelymore » due to a higher driving force for charge injection into the more positive conduction band energy of SnO 2. Dyeing conditions and SnO 2 film thickness were subsequently optimized to achieve light-harvesting efficiency >99% at the λmax of the dye, and absorbed photon-to-current efficiency of 13% with H 2Q, a 2-fold improvement over the previous thin-film architecture. A CoO x water-oxidation catalyst was photoelectrochemically deposited, allowing for photoelectrochemical water oxidation with a faradaic efficiency of 31 ± 7%, thus demonstrating the second example of a water-oxidizing, dye-sensitized photoelectrolysis cell composed entirely of earth-abundant materials. However, deposition of CoO x always results in lower photocurrent due to enhanced recombination between catalyst and photoinjected electrons in SnO 2, as confirmed by open-circuit photovoltage measurements. Possible future studies to enhance photoanode performance are also discussed, including alternative catalyst deposition strategies or structural derivatization of the perylene dye.« less

Mediator-assisted decolorization and detoxification of textile dyes/dye mixture by Cyathus bulleri laccase.

PubMed

Chhabra, Meenu; Mishra, Saroj; Sreekrishnan, T R

2008-12-01

Laccase from basidiomycete fungus Cyathus bulleri was evaluated for its ability to decolorize a number of reactive and acidic dyes in the presence of natural and synthetic mediators. The extent of decolorization was monitored at different mediator/dye concentrations and incubation time. Among the synthetic mediators, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) was effective at low mediator/dye ratios and resulted in 80-95% decolorization at rates that varied from 226 +/- 4 nmol min(-1) mg(-1) for Reactive Orange 1 to 1,333 +/- 15 nmol min(-1) mg(-1) for Reactive Red 198. Other synthetic mediators like 1-hydroxybenzotriazole and violuric acid showed both concentration- and time-dependent increases in percent decolorization. Natural mediators like vanillin, on the other hand, were found to be less effective on all the dyes except Reactive Orange 1. Computed rates of decolorization were about twofold lower than that with ABTS. The laccase-ABTS system also led to nearly 80% decolorization for the simulated dye mixture. No clear correlation between laccase activity on the mediator and its ability to decolorize dyes was found, but pH had a significant effect: Optimum pH for decolorization coincided with the optimum pH for mediator oxidation. The treated samples were also evaluated for toxicity in model microbial systems. The laccase-mediator system appears promising for treatment of textile wastewaters.

Probing horseradish peroxidase catalyzed degradation of azo dye from tannery wastewater.

PubMed

Preethi, Sadhanandam; Anumary, Ayyappan; Ashokkumar, Meiyazhagan; Thanikaivelan, Palanisamy

2013-01-01

Biocatalysis based effluent treatment has outclassed the presently favored physico-chemical treatments due to nil sludge production and monetary savings. Azo dyes are commonly employed in the leather industry and pose a great threat to the environment. Here, we show the degradation of C. I. Acid blue 113 using horseradish peroxidase (HRP) assisted with H2O2 as a co-substrate. It was observed that 0.08 U HRP can degrade 3 mL of 30 mg/L dye up to 80% within 45 min with the assistance of 14 μL of H2O2 at pH 6.6 and 30°C. The feasibility of using the immobilized HRP for dye degradation was also examined and the results show up to 76% dye degradation under similar conditions to that of free HRP with the exception of longer contact time of 240 min. Recycling studies reveal that the immobilized HRP can be recycled up to 3 times for dye degradation. Kinetics drawn for the free HRP catalyzed reaction marked a lower K m and higher V max values, which denotes a proper and faster affinity of the enzyme towards the dye, when compared to the immobilized HRP. The applicability of HRP for treating the actual tannery dye-house wastewater was also demonstrated.

Effective degradation of primary color direct azo dyes using Fe0 aggregates-activated persulfate process.

PubMed

Liu, Na; Ding, Feng; Weng, Chih-Huang; Hwang, Chi-Chin; Lin, Yao-Tung

2018-01-15

The present study examined the oxidation power of a Fe 0 aggregates/persulfate (PS/Fe 0 ) system for the degradation of the wastewater containing mixed primary direct dyes (i.e., Sirius ® Gelb S-2G, Sirius ® Red F3B, and Sirius ® Turkis GL01). Results indicated that decolorization efficiency was determined by operating parameters of the PS/Fe 0 system and the structural complexity of dye molecules. System efficiency increased with increasing persulfate and Fe 0 dosages. Faster decolorization was observed in experiments conducted at pH < 10. The process obeyed a first-order kinetics. Slow heterogeneous reactions were observed at high initial pH (>10.5) and low PS concentration (<2 × 10 -3  M). Inhibitory effect occurred in systems containing salts Na 2 SO 4 , NaCl, Na 2 CO 3 , and Na 2 HPO 4 at 1 × 10 -2  M. The effect was suppressed when reaction temperature was raised to 55 °C. Heat enhanced not only decolorization efficiency, but also COD removal. Complete decolorization of a mixed dye containing ADMI (the American Dye Manufacture Institute) 15105 was achieved within10 min in the PS/Fe 0 /55 °C system with an initial pH of 6.0 and dosages of 5 × 10 -3  M Na 2 S 2 O 8 and 0.5 g/L Fe 0 . Low molecular weight intermediates including organic acids were identified. Due to a relatively low activation energy (4.68 kcaL/mol), the PS/Fe 0 system exhibited higher efficiency at higher temperature. This study demonstrated that Fe 0 -activated PS is a promising process for the treatment of textile wastewaters containing mixed azo direct dyes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis, spectroscopic characterization and biological evaluation of unsymmetrical aminosquarylium cyanine dyes.

PubMed

Friães, Sofia; Silva, Amélia M; Boto, Renato E; Ferreira, Diana; Fernandes, José R; Souto, Eliana B; Almeida, Paulo; Ferreira, Luis F Vieira; Reis, Lucinda V

2017-07-15

New unsymmetrical aminosquarylium cyanine dyes were synthesized and their potential as photosensitizers evaluated. New dyes, derived from benzothiazole and quinoline, were prepared by nucleophilic substitution of the corresponding O-methylated, the key intermediate that was obtained by methylation with CF 3 SO 3 CH 3 of the related zwitterionic unsymmetrical dye, with ammonia and methylamine, respectively. All three news dyes herein described displayed intense and narrow bands in the Vis/NIR region (693-714nm) and their singlet oxygen formation quantum yields ranged from 0.03 to 0.05. In vitro toxicity, in Caco-2 and HepG2 cells, indicated that dark toxicity was absent for concentrations up to 5µM (for the less active dye) or up to 1µM (for the two more active dyes). The three dyes present potential as photosensitizers, differing in irradiation conditions and period of incubation in the presence of irradiated dye. The less active dye needs a longer irradiation period to exhibit phototoxicity which is only evident after longer period of contact with cells (24h). However, the remaining two more active dyes produce higher phototoxicity, even at shorter incubation periods (1h), with shorter irradiation time (7min). Although in different extents, these dyes show promising in vitro results as photosensitizers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Direct Analysis of Textile Fabrics and Dyes Using IR Matrix-Assisted Laser Desorption Electrospray Ionization (MALDESI) Mass Spectrometry

PubMed Central

Cochran, Kristin H.; Barry, Jeremy A.; Muddiman, David C.; Hinks, David

2012-01-01

The forensic analysis of textile fibers uses a variety of techniques from microscopy to spectroscopy. One such technique that is often used to identify the dye(s) within the fiber is mass spectrometry (MS). In the traditional MS method, the dye must be extracted from the fabric and the dye components are separated by chromatography prior to mass spectrometric analysis. Direct analysis of the dye from the fabric allows the omission of the lengthy sample preparation involved in extraction, thereby significantly reducing the overall analysis time. Herein, a direct analysis of dyed textile fabric was performed using the infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source for MS. In MALDESI, an IR laser with wavelength tuned to 2.94 μm is used to desorb the dye from the fabric sample with the aid of water as the matrix. The desorbed dye molecules are then post-ionized by electrospray ionization (ESI). A variety of dye classes were analyzed from various fabrics with little to no sample preparation allowing for the identification of the dye mass and in some cases the fiber polymer. Those dyes that were not detected using MALDESI were also not observed by direct infusion ESI of the dye standard. PMID:23237031

Optimization of photocatalytic degradation of sulphonated diazo dye C.I. Reactive Green 19 using ceramic-coated TiO2 nanoparticles.

PubMed

Rastegar, M; Shadbad, K Rahmati; Khataee, A R; Pourrajab, R

2012-01-01

Optimization of photocatalytic degradation of C.I. Reactive Green 19 (RG 19) under UV light irradiation using ceramic-coated TiO2 nanoparticles in a continuous circulation rectangular photoreactor was studied. The used catalyst was TiO2 Millennium PC-500 (crystallite mean size 8 nm) immobilized on ceramic plates. A central composite design was used for optimization of the UV/TiO2 process. Predicted values of decolorization efficiency were found to be in good agreement with experimental values (R2 = 0.97 and Adj-R2 = 0.91). Optimization results showed that maximum decolorization efficiency was achieved at the optimum conditions of: initial dye concentration 10 mg/L, UV light intensity 47.2 W/m2, flow rate 150 mL/min and reaction time 240 min. Photocatalytic mineralization of RG 19 was monitored by chemical oxygen demand (COD) decrease and changes in the UV-Vis spectrum.

Activated bauxite waste as an adsorbent for removal of Acid Blue 92 from aqueous solutions.

PubMed

Norouzi, Sh; Badii, Kh; Doulati Ardejani, F

2010-01-01

Bauxite waste, known as red mud, is produced in some industrial processes, such as aluminum production process. In this process, the waste material is produced from leached bauxite as a by product. In this research, the removal of Acid Blue 92 (AB92) dye was investigated from aqueous solution onto the activated bauxite waste (red mud) in a batch equilibration system. Besides, the influences of pH, adsorbent dosage, contact time, initial concentration of dye and temperature have been considered. It was found that the OH group is an effective functional group for the adsorption process. The intensity of the peaks correspond to OH group has been significantly climbed after the activation process. The adsorption kinetics of AB92 can be well described by the pseudo-second-order reaction model. Based on the isotherm data obtained from the fittings of the adsorption kinetics, the Langmuir model appears to fit the adsorption process better than the Freundlich and Brunauer-Emmett-Teller (BET) models.

Vitamin C for stabilising biological lasers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kar, Ajoy K.; Mackenzie, Mark D.; Cialowicz, Katarzyna I.; Saleeb, Rebecca S.; Duncan, Rory R.

2016-04-01

We report on efforts to improve the lifetime of biological lasers through the use of ascorbic acid (also commonly known as vitamin C). Fluorescent proteins and dyes, used in biological lasers, suffer from photobleaching due to the build-up of reactive oxygen species (ROS) which causes damage leading to a decrease in emission over time. This is an issue both for laser lifetime and cell health. It has previously been shown that ascorbic acid can be effective in reducing ROS levels in a variety of applications. For our experiments human embryonic kidney cells (HEK293), containing the fluorescent dye Calcein AM, were placed between two dielectric plane mirrors to form a laser cavity. The cells were pumped using the output of a Ti:Sapphire femtosecond OPO system, frequency doubled twice in BBO crystals, giving an output of 474 nm. Initial results have shown an increase in laser lifetime when ascorbic acid is added to cells indicating a reduction in the build-up of ROS.

Statistical Correlation between Ligninolytic Enzymes Secretion and Remazol Brilliant Yellow-3GL Dye Degradation Potential of Trametes versicolor IBL-04.

PubMed

Asgher, Muhammad; Shah, Syed Agha Hassan; Iqbal, Hafiz Muhammad Nasir

2016-04-01

Trametes versicolor IBL-04 was used for biodegradation of Remazol Brilliant Yellow 3-GL (RBY3-GL) reactive textile dye in Kirk's basal salts medium. During the initial screening study, the maximum decolorization (93.5%) of RBY3-GL was achieved in 7 days' shaking incubation period at pH 4 and 30 °C. Different physical and nutritional factors were statistically optimized to enhance the efficiency of T. versicolor IBL-04 for maximum decolorization. Under optimal conditions T. versicolor IBL-04 completely decolorized (100%) the RBY3-GL in 2 days of incubation with negligible adsorption on fungal mycelia. Laccase was the major enzyme (938.3 U/mL) secreted by T. versicolor IBL-04 along with comparatively lower activities of MnP. In this article and for the first time, a statistical correlation has been successfully investigated between the ligninolytic enzymes from an indigenously isolated white rot fungi, T. versicolor IBL-04, and the degradation of RBY3-GL.

Efficiency Improvement of Some Agricultural Residue Modified Materials for Textile Dyes Absorption

NASA Astrophysics Data System (ADS)

Boonsong, P.; Paksamut, J.

2018-03-01

In this work, the adsorption efficiency was investigated of some agricultural residue modified materials as natural bio-adsorbents which were rice straw (Oryza sativa L.) and pineapple leaves (Ananas comosus (L.) Merr.) for the removal of textile dyes. Reactive dyes were used in this research. The improvement procedure of agricultural residue materials properties were alkali-acid modification with sodium hydroxide solution and hydrochloric acid solution. Adsorption performance has been investigated using batch experiments. Investigated adsorption factors consisted of adsorbent dose, contact time, adsorbent materials and pH of solution. The results were found that rice straw had higher adsorption capacity than pineapple leaves. The increasing of adsorption capacity depends on adsorbent dose and contact time. Moreover, the optimum pH for dye adsorption was acidic range because lowering pH increased the positively charges on the adsorbent surface which could be attacked by negatively charge of acid dyes. The agricultural residue modified materials had significant dye removal efficiency which these adsorbents could be used for the treatment of textile effluent in industries.

By-product identification and phytotoxicity of biodegraded Direct Yellow 4 dye.

PubMed

Nouren, Shazia; Bhatti, Haq Nawaz; Iqbal, Munawar; Bibi, Ismat; Kamal, Shagufta; Sadaf, Sana; Sultan, Misbah; Kausar, Abida; Safa, Yusra

2017-02-01

Citrus limon peroxidase mediated decolourization of Direct Yellow 4 (DY4) was investigated. The process variables (pH, temperature, incubation time, enzyme dose, H 2 O 2 amount, dye concentration, co-metal ions and surfactants) were optimized for maximum degradation of dye. Maximum dye decolourization of 89.47% was achieved at pH 5.0, temperature 50 °C, enzyme dose 24 U/mL, H 2 O 2 concentration 0.25 mM and DY4 concentration 18.75 mg/L and incubation time 10 min. The co-metal ions and surfactants did not affect the dye decolourization significantly. Response surface analysis revealed that predicted values were in agreement with experimentally determined responses. The degradation products were identified by UPLC/MS analysis and degradation pathway was proposed. Besides, phytotoxicity assay revealed a considerable detoxification in response of biodegradation of DY4 dye. C. limon showed promising efficiency for DY4 degradation and could possibly be used for the remediation of textile effluents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Continuous electrochemical oxidation of methyl orange waste water using a three-dimensional electrode reactor.

PubMed

Liu, Zhigang; Wang, Feifei; Li, Yansheng; Xu, Tianlong; Zhu, Shaomin

2011-06-01

The removal of methyl orange wastewater was experimentally investigated using a three-dimensional electrode reactor with granular activated carbon and titanium filter electrodes arrays. The effects of the electric current, the residence time and the initial dye concentration on the methyl orange removal were evaluated. For the initial concentration of 1150 mg/L, the COD removal was obtained as 90% under the conditions of electric current 2 A, residence time 40 min. The effluent path of the electrochemical cell was optimized, using the anode effluent instead of the top effluent, where the COD removal was increased to 93% and the corresponding energy consumption was decreased from 15.5 to 14.6 kW-hr/kg COD. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Parametric and energy consumption optimization of Basic Red 2 removal by electrocoagulation/egg shell adsorption coupling using response surface methodology in a batch system.

PubMed

de Carvalho, Helder Pereira; Huang, Jiguo; Zhao, Meixia; Liu, Gang; Yang, Xinyu; Dong, Lili; Liu, Xingjuan

2016-01-01

In this study, response surface methodology (RSM) model was applied for optimization of Basic Red 2 (BR2) removal using electrocoagulation/eggshell (ES) coupling process in a batch system. Central composite design was used to evaluate the effects and interactions of process parameters including current density, reaction time, initial pH and ES dosage on the BR2 removal efficiency and energy consumption. The analysis of variance revealed high R(2) values (≥85%) indicating that the predictions of RSM models are adequately applicable for both responses. The optimum conditions when the dye removal efficiency of 93.18% and energy consumption of 0.840 kWh/kg were observed were 11.40 mA/cm(2) current density, 5 min and 3 s reaction time, 6.5 initial pH and 10.91 g/L ES dosage.

Enzymatic decolourisation of Methyl Orange and Bismarck Brown using crude peroxidase from Armoracia rusticana

NASA Astrophysics Data System (ADS)

Ambatkar, Mugdha; Mukundan, Usha

2015-12-01

The decolourisation of Methyl Orange (MO) and Bismarck Brown (BB) by crude peroxidase from Armoracia rusticana (Horseradish) was studied by varying different reaction parameters. The pH of the reaction mixture, initial dye concentration, amount of enzyme and hydrogen peroxide concentration were optimised for ambient temperatures (30 ± 2 °C). The optimum pH for decolourisation was 4.0 (72.95 %) and 3.0 (79.24 %) for MO and BB, respectively. Also it was found that the Chemical Oxygen Demand of the enzyme-treated sample was significantly lower than that of the untreated controls for both dyes. The addition of a complex iron salt like Ferric EDTA was found to enhance the decolourisation of both dyes at pH 6.0, showing an increase of 8.69 % and 14.17 % in the decolourisation of MO and of BB, respectively. The present study explores the potential of crude peroxidase from horseradish to decolourise representative monoazo and diazo dyes, MO and BB, respectively. An attempt has been made to utilise a crude enzyme with appreciable activity obtained after minimal processing for the decolourisation of the aforesaid dyes. The findings of this study would find application in the enzymatic treatment of wastewater containing azo dyes.

Efficient azo dye decolorization in a continuous stirred tank reactor (CSTR) with built-in bioelectrochemical system.

PubMed

Cui, Min-Hua; Cui, Dan; Gao, Lei; Cheng, Hao-Yi; Wang, Ai-Jie

2016-10-01

A continuous stirred tank reactor with built-in bioelectrochemical system (CSTR-BES) was developed for azo dye Alizarin Yellow R (AYR) containing wastewater treatment. The decolorization efficiency (DE) of the CSTR-BES was 97.04±0.06% for 7h with sludge concentration of 3000mg/L and initial AYR concentration of 100mg/L, which was superior to that of the sole CSTR mode (open circuit: 54.87±4.34%) and the sole BES mode (without sludge addition: 91.37±0.44%). The effects of sludge concentration and sodium acetate (NaAc) concentration on azo dye decolorization were investigated. The highest DE of CSTR-BES for 4h was 87.66±2.93% with sludge concentration of 12,000mg/L, NaAc concentration of 2000mg/L and initial AYR concentration of 100mg/L. The results in this study indicated that CSTR-BES could be a practical strategy for upgrading conventional anaerobic facilities against refractory wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Adsorption orientation effects of porphyrin dyes on the performance of DSSC: Comparison of benzoic acid and tropolone anchoring groups binding onto the TiO2 anatase (101) surface

NASA Astrophysics Data System (ADS)

Zhu, Han-Cheng; Zhang, Ji; Wang, Ying-Lin

2018-03-01

A new porphyrin dye with tropolone anchoring group showing superior stability but lower efficiency versus the promising dye YD2-o-C8 with benzoic acid anchoring group was theoretically investigated for the first time. A series of important parameters related to the efficiency of DSSC were calculated to explore the nature of the experimentally observed lower efficiency and superior stability of tropolone-based solar cells. We found these two dyes with different anchoring groups show comparable electron injection and dye regeneration process. Interestingly, the red-shifted absorption spectrum, relatively weaker ability of releasing protons, and the larger conduction band energy shift of tropolone-based dyes all demonstrated it should show better performance than the benzoic acid dyes, which contradicts with the experimental results. However, through investigating the interaction between the porphyrin dye and the semiconductor by analyzing the electron localization function of the porphyrin dye and preforming energy decomposition analysis, we found that the direction of lone-pair electrons of carbonyl oxygen in the tropolone-based dye makes the dye prefer to adsorb on the surface in an inclined way, in contrary to the benzoic acid-based dye that favored a vertical adsorption. The inclined adsorption could significantly accelerate the charge recombination process between the injected electrons and the oxidized dye, leading to a decreased efficiency of DSSC.

Response surface methodology optimization for sorption of malachite green dye on sugarcane bagasse biochar and evaluating the residual dye for phyto and cytogenotoxicity.

PubMed

Vyavahare, Govind D; Gurav, Ranjit G; Jadhav, Pooja P; Patil, Ravishankar R; Aware, Chetan B; Jadhav, Jyoti P

2018-03-01

In the present study, sorption and detoxification of malachite green (MG) dye was executed using biochar resulting after pyrolysis of agro-industrial waste at 400, 600 and 800 °C. Maximum sorption of MG dye (3000 mg/L) was observed on the sugarcane bagasse biochar (SCB) prepared at 800 °C. The interactive effects of different factors like dye concentration, time, pH and temperature on sorption of MG dye were investigated using response surface methodology (RSM). Optimum MG dye concentration, contact time, temperature and pH predicted through Box-Behnken based RSM model were 3000 mg/L MG dye, 51.89 min, 60 °C and 7.5, respectively. ANOVA analysis displayed the non-significant lack of fit value (0.4566), whereas, the predicted correlation coefficient values (R 2 0.8494) were reasonably in agreement with the adjusted value (R 2 0.9363) demonstrating highly significant model for MG dye sorption. The applicability of this model was also checked through F- test (30.39) with lower probability (0.0001) value. Furthermore, the characterization of SCB was performed using fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), Brunauer-Emmett-Teller surfaces (BET), total organic carbon (TOC) and atomic absorption spectroscopy (AAS). Phyto-toxicity and cytogenotoxicity studies showed successful removal of MG dye using SCB. In addition, the batch sorption studies for reutilization of SCB revealed that the SCB was effective in removal of MG for five repeated cycles. This technology would be effective for treating the toxic textile effluent released from the textile industries. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Adsorption of a dye by sludges and the roles of extracellular polymeric substances].

PubMed

Kong, Wang-sheng; Liu, Yan

2007-12-01

This paper investigated the adsorption of a dye, acid turquoise blue A, by four kinds of sludges including activated sludge, anaerobic sludge, dried activated sludge, and dried anaerobic sludge, respectively. The roles of extracellular polymeric substances (EPS) including the soluble EPS (SEPS) and bound EPS (BEPS) for the biosorption of activated sludge and anaerobic sludge were further studied. Results show that the relation between four kinds of sludge adsorption amount and remained concentration of the dye fitted well both Freundlich model (R2: 0.921-0.995) and Langmuir model (R2: 0.958-0.993), but not quite fitted BET model (R2: 0.07-0.863). The adsorption capability of dried anaerobic sludge ranked the highest, and dried activated sludge was the lowest. According to Langmuir isotherm, the maximum adsorption amount of dried anaerobic, anaerobic, activated, and dried activated sludge was 104 mg/g, 86 mg/g, 65 mg/g, 20 mg/g, respectively. The amount of the dye found in EPS for both activated sludge and anaerobic sludge were over 50%, illustrating that EPS adsorption was predominant in adsorption of the dye by sludge. The amount of adsorbed dye by BEPS was greater than that by SEPS for anaerobic sludge, but for activated sludge the result was quite opposite. The amount of adsorbed dye by unit mass SEPS was much higher than the corresponding values of BEPS for both sludges. The average amount of adsorbed dye by unit mass SEPS was 52 times of the corresponding value of BEPS for activated sludge, and 10 times for anaerobic sludge. The relation between adsorption amount of dye by BEPS from anaerobic sludge and remained concentration of the dye in mixed liquor was best fitted to Langmuir model (R2: 0.9986).

Extrinsic Fluorescent Dyes as Tools for Protein Characterization

PubMed Central

Hawe, Andrea; Sutter, Marc

2008-01-01

Noncovalent, extrinsic fluorescent dyes are applied in various fields of protein analysis, e.g. to characterize folding intermediates, measure surface hydrophobicity, and detect aggregation or fibrillation. The main underlying mechanisms, which explain the fluorescence properties of many extrinsic dyes, are solvent relaxation processes and (twisted) intramolecular charge transfer reactions, which are affected by the environment and by interactions of the dyes with proteins. In recent time, the use of extrinsic fluorescent dyes such as ANS, Bis-ANS, Nile Red, Thioflavin T and others has increased, because of their versatility, sensitivity and suitability for high-throughput screening. The intention of this review is to give an overview of available extrinsic dyes, explain their spectral properties, and show illustrative examples of their various applications in protein characterization. PMID:18172579

Fluorometric procedures for dye tracing

USGS Publications Warehouse

Wilson, James F.; Cobb, Ernest D.; Kilpatrick, F.A.

1986-01-01

This manual describes the current fluorometric procedures used by the U.S. Geological Survey in dye tracer studies such as time of travel, dispersion, reaeration, and dilution-type discharge measurements. The advantages of dye tracing are (1) low detection and measurement limits and (2) simplicity and accuracy in measuring dye tracer concentrations using fluorometric techniques. The manual contains necessary background information about fluorescence, dyes, and fluorometers and a description of fluorometric operation and calibration procedures as a guide for laboratory and field use. The background information should be useful to anyone wishing to experiment with dyes, fluorometer components, or procedures different from those described. In addition, a brief section on aerial photography is included because of its possible use to supplement ground-level fluorometry.

Fluorometric procedures for dye tracing

USGS Publications Warehouse

Wilson, James F.

1968-01-01

This manual describes the current fluorometric procedures used by the U.S. Geological Survey in dye tracer studies such as time of travel, dispersion, reaeration, and dilution-type discharge measurements. The advantages of dye tracing are (1) low detection and measurement limits and (2) simplicity and accuracy in measuring dye tracer concentrations using fluorometric techniques. The manual contains necessary background information about fluorescence, dyes, and fluorometers and a description of fluorometric operation and calibration procedures as a guide for laboratory and field use. The background information should be useful to anyone wishing to experiment with dyes, fluorometer components, or procedures different from those described. In addition, a brief section on aerial photography is included because of its possible use to supplement ground-level fluorometry.

Fluorometric procedures for dye tracing

USGS Publications Warehouse

Wilson, James E.; Cobb, Ernest D.; Kilpatrick, Frederick A.

1984-01-01

This manual describes the current fluorometric procedures used by the U.S. Geological Survey in dye tracer studies such as time of travel, dispersion, reaeration, and dilution-type discharge measurements. The outstanding characteristics of dye tracing are: (1) the low detection and measurement limits, and (2) the simplicity and accuracy of measuring dye tracer concentrations using fluorometric techniques. The manual contains necessary background information about fluorescence, dyes, and fluorometers and a description of fluorometric operation and calibration procedures as a general guide for laboratory and field use. The background information should be useful to anyone wishing to experiment with dyes, fluorometer components, or procedures different from those described. In addition, a brief section is included on aerial photography because of its possible use to supplement ground-level fluorometry.

Effect of polymer electrolyte on the performance of natural dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Adel, R.; Abdallah, T.; Moustafa, Y. M.; Al-sabagh, A. M.; Talaat, H.

2015-10-01

Polymer electrolyte based on polyacrylonitrile (PAN), Ethylene Carbonate (EC) and Acetonitrile (ACN) mixed with Potassium Iodide and Iodine in liquid and thin film forms were employed in natural dye sensitized solar cells (NDSSCs). Three natural dyes; black berry, hibiscus and rose are used as the sensitizing dye. The NDSSCs used, follow the configuration: FTO/TiO2/Natural Dye/Electrolyte/ Carbon/FTO. The liquid form polymer electrolyte with black berry natural dye gives an increase of 111% in short circuit photocurrent density (Jsc), 17.5% to open circuit voltage (Voc), fill factor of 0.57 ± 0.05 and three times increase in the conversion efficiency of 0.242 ± 0.012% compared to the iodine electrolyte.

Development and validation of an open source O2-sensitive gel for physiological profiling of soil microbial communities.

PubMed

McLamore, E S; Garland, J L; Mackowiak, C; Desaunay, A; Garland, N; Chaturvedi, P; Taguchi, M; Dreaden, K; Catechis, John; Ullman, J L

2014-01-01

Community level physiological profiling is a simple, high-throughput technique for assessing microbial community physiology. Initial methods relying on redox-dye based detection of respiration were subject to strong enrichment bias, but subsequent development of a microtiter assay using an oxygen-quenched dye reduced this bias and improved the versatility of the approach. Commercial production of the oxygen microplates recently stopped, which led to the present effort to develop and validate a system using a luminophore dye (platinum tetrakis pentafluorophenyl) immobilized at the bottom of wells within a 96 well microtiter plate. The technique was used to analyze three well-characterized Florida soils: oak saw palmetto scrub, coastal mixed hardwood, and soil from an agricultural field used to grow corn silage. Substrate induced respiration was monitored by measuring respiration rates in soils under basal conditions and comparing to soils supplemented with nitrogen and various carbon sources (mannose, casein, asparagine, coumaric acid). All data was compared to a previously available commercial assay. There were no significant differences in the maximum peak intensity or the time to peak response for all soils tested (p<0.001, α=0.05). The experimental assay plates can be reused on soils up to four times (based on a deviation of less than 5%), where the commercial assay should not be reused. The results indicate that the new oxygen-based bioassay is a cost effective, open source tool for functional profiling of microbial communities. Copyright © 2013 Elsevier B.V. All rights reserved.

Biphasic reduction model for predicting the impacts of dye-bath constituents on the reduction of tris-azo dye Direct Green-1 by zero valent iron (Fe0).

PubMed

Kumar, Raja; Sinha, Alok

2017-02-01

Influence of common dye-bath additives, namely sodium chloride, ammonium sulphate, urea, acetic acid and citric acid, on the reductive decolouration of Direct Green 1 dye in the presence of Fe 0 was investigated. Organic acids improved dye reduction by augmenting Fe 0 corrosion, with acetic acid performing better than citric acid. NaCl enhanced the reduction rate by its 'salting out' effect on the bulk solution and by Cl - anion-mediated pitting corrosion of iron surface. (NH 4 ) 2 SO 4 induced 'salting out' effect accompanied by enhanced iron corrosion by SO 4 2- anion and buffering effect of NH 4 + improved the reduction rates. However, at 2g/L (NH 4 ) 2 SO 4 concentration, complexating of SO 4 2- with iron oxides decreased Fe 0 reactivity. Urea severely compromised the reduction reaction, onus to its chaotropic and 'salting in' effect in solution, and due to it masking the Fe 0 surface. Decolouration obeyed biphasic reduction kinetics (R 2 >0.993 in all the cases) exhibiting an initial rapid phase, when more than 95% dye reduction was observed, preceding a tedious phase. Maximum rapid phase reduction rate of 0.955/min was observed at pH2 in the co-presence of all dye-bath constituents. The developed biphasic model reckoned the influence of each dye-bath additive on decolouration and simulated well with the experimental data obtained at pH2. Copyright © 2016. Published by Elsevier B.V.

Effect of K2FeO4/US treatment on textile dyeing sludge disintegration and dewaterability.

PubMed

Ning, Xun-an; Feng, Yinfang; Wu, Junji; Chen, Changmin; Wang, Yujie; Sun, Jian; Chang, Kenlin; Zhang, Yaping; Yang, Zuoyi; Liu, Jingyong

2015-10-01

The effect of potassium ferrate/ultrasonic (K2FeO4/US) treatment on the physicochemical features of textile dyeing sludge was studied. The soluble chemical oxygen demand (SCOD), deoxyribonucleic acid (DNA), sludge volume index (SVI), sludge viscosity, capillary suction time (CST) and particle size were measured to understand the observed changes in the sludge physicochemical features. The results showed that the combined K2FeO4/US treatment presented great advantages for disrupting the sludge floc structure over K2FeO4 or ultrasonic treatments alone. The optimal parameters of sludge disintegration were found to be a K2FeO4 treatment time of 60 min, a K2FeO4 dosage of 0.5936 g/g SS, an ultrasonic time of 15 min and an ultrasonic intensity of 0.72 W/mL. The initial median diameter of the sludge particles was 15.24 μm, and this value decreased by 35.89%. The CST was initially 59.6 s and increased by 231%, whereas the SVI was 97.78 mL/g and decreased by 25.89%. Scanning electron microscope (SEM) images indicated that the sludge surface was irregular and loose with a large amount of channels or voids during K2FeO4/US treatment. K2FeO4/US treatment synergistically enhanced the sludge solubilization and reached 668.67 mg/L SCOD, which is 31.81% greater than the additive value obtained with K2FeO4 treatment alone (215.95 mg/L) or with ultrasonic treatment alone (240 mg/L). Copyright © 2015 Elsevier Ltd. All rights reserved.

Rationalizing the suitability of rhodamines as chromophores in dye-sensitized solar cells: A systematic molecular design study

DOE PAGES

Pepe, Giulio; Cole, Jacqueline M.; Waddell, Paul G.; ...

2016-09-30

Here, rhodamines are chromophores that are employed in many dye applications. Their strong optical absorption in the visible region of the electromagnetic spectrum renders them attractive dye candidates for dye-sensitized solar cells (DSCs). However, they have not yet been systematically tested in DSCs as single- or co-sensitizers. Recent advances in concerted experimental and computational workflows involving molecular design protocols can afford a better understanding of the molecular origins of the optoelectronic properties in these sensitizers. Herein, we examine the suitability of rhodamines R560 (1), R575 (2), R590 (3), R610 (4), R620 (5), R640 (6), and R3B (7) as chromophores inmore » co-sensitized DSCs. Our study follows a stepwise approach. Initially, structural and optical properties of the dyes are investigated by experimental and computational methods to reveal structure-property relationships and other useful features for DSC applications. Subsequently, 1-7 are investigated at the dye···TiO 2 interface, both by calculations of dye-adsorption onto the surface of a modeled (TiO 2) 9 cluster, and by experimental studies of dye-adsorption on TiO 2. For that purpose, a selection of rhodamine dyes are paired together (1 and 5) and (1 and 7) for co-sensitization, among which 5 is also co-adsorbed with a fluorescein dye in order to explore chemical compatibility factors. The best dye candidates are identified from the findings of these adsorption studies in terms of dye aggregation, anchoring modes, and panchromatic response. Despite their promising dye…TiO 2 adsorption and optical prospects, our results show that rhodamines lack a suitable intramolecular charge transfer pathway for dye-to-TiO 2 electron injection to occur, thus precluding their photovoltaic function as DSC dyes. Our results are then assessed against ostensibly disparate reports of rhodamines performing successfully in DSC devices; this comparison necessitated the internal reproduction of previously reported co-sensitization experiments on 2 with the industrial standard reference dye, N3. We achieve reconciliation between our results and those in the literature by reasoning that while rhodamines cannot deliver photovoltaic function in DSCs in their own right, they can either act to facilitate or deplete the photovoltaic output of a DSC indirectly by affecting the TiO 2 adsorption prospects of a photovoltaic-active dye with which a rhodamine is co-sensitized.« less

Adsorption performance of mixed dyes on alkalization loofah fibers

NASA Astrophysics Data System (ADS)

Wang, Yongli; Liu, Jinyan; Li, Xingxing

2018-02-01

When the polyporous structures of loofah fiber is adequately exposed after alkali treatment,lignin, hemicellulose and pectin are removed. Specific surface area is increased to maximum, which means the efficiency of absorptivity is highest. In this paper, by using alkalization loofah (AL) as adsorbent, the effect of loofah fiber on waste water treatment is studied under the efficiency of loofah fiber which contain acridine yellow, methylene blue, mixed solution of the two dyes. The optimum treatment conditions of loofah fiber were studied from five aspects which include dosage, temperature, mixing time, pH and concentration. The results showed that the optimal conditions are 30°C, pH 8.0, 20mg dosage of loofah fiber in 40ml solution and mixing time 25min. The optimal treatment conditions of mixed dyes were studied from the aspects of mixing time, the dosage of AL and the molar ratio of the two components in the mixed dyes.

Accurate distance determination of nucleic acids via Förster resonance energy transfer: implications of dye linker length and rigidity.

PubMed

Sindbert, Simon; Kalinin, Stanislav; Nguyen, Hien; Kienzler, Andrea; Clima, Lilia; Bannwarth, Willi; Appel, Bettina; Müller, Sabine; Seidel, Claus A M

2011-03-02

In Förster resonance energy transfer (FRET) experiments, the donor (D) and acceptor (A) fluorophores are usually attached to the macromolecule of interest via long flexible linkers of up to 15 Å in length. This causes significant uncertainties in quantitative distance measurements and prevents experiments with short distances between the attachment points of the dyes due to possible dye-dye interactions. We present two approaches to overcome the above problems as demonstrated by FRET measurements for a series of dsDNA and dsRNA internally labeled with Alexa488 and Cy5 as D and A dye, respectively. First, we characterize the influence of linker length and flexibility on FRET for different dye linker types (long, intermediate, short) by analyzing fluorescence lifetime and anisotropy decays. For long linkers, we describe a straightforward procedure that allows for very high accuracy of FRET-based structure determination through proper consideration of the position distribution of the dye and of linker dynamics. The position distribution can be quickly calculated with geometric accessible volume (AV) simulations, provided that the local structure of RNA or DNA in the proximity of the dye is known and that the dye diffuses freely in the sterically allowed space. The AV approach provides results similar to molecular dynamics simulations (MD) and is fully consistent with experimental FRET data. In a benchmark study for ds A-RNA, an rmsd value of 1.3 Å is achieved. Considering the case of undefined dye environments or very short DA distances, we introduce short linkers with a propargyl or alkenyl unit for internal labeling of nucleic acids to minimize position uncertainties. Studies by ensemble time correlated single photon counting and single-molecule detection show that the nature of the linker strongly affects the radius of the dye's accessible volume (6-16 Å). For short propargyl linkers, heterogeneous dye environments are observed on the millisecond time scale. A detailed analysis of possible orientation effects (κ(2) problem) indicates that, for short linkers and unknown local environments, additional κ(2)-related uncertainties are clearly outweighed by better defined dye positions.

Characterization of Natural Dyes and Traditional Korean Silk Fabric by Surface Analytical Techniques.

PubMed

Lee, Jihye; Kang, Min Hwa; Lee, Kang-Bong; Lee, Yeonhee

2013-05-15

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) are well established surface techniques that provide both elemental and organic information from several monolayers of a sample surface, while also allowing depth profiling or image mapping to be carried out. The static TOF-SIMS with improved performances has expanded the application of TOF-SIMS to the study of a variety of organic, polymeric and biological materials. In this work, TOF-SIMS, XPS and Fourier Transform Infrared (FTIR) measurements were used to characterize commercial natural dyes and traditional silk fabric dyed with plant extracts dyes avoiding the time-consuming and destructive extraction procedures necessary for the spectrophotometric and chromatographic methods previously used. Silk textiles dyed with plant extracts were then analyzed for chemical and functional group identification of their dye components and mordants. TOF-SIMS spectra for the dyed silk fabric showed element ions from metallic mordants, specific fragment ions and molecular ions from plant-extracted dyes. The results of TOF-SIMS, XPS and FTIR are very useful as a reference database for comparison with data about traditional Korean silk fabric and to provide an understanding of traditional dyeing materials. Therefore, this study shows that surface techniques are useful for micro-destructive analysis of plant-extracted dyes and Korean dyed silk fabric.

Characterization of domain-specific interaction of synthesized dye with serum proteins by spectroscopic and docking approaches along with determination of in vitro cytotoxicity and antiviral activity.

PubMed

Rudra, Suparna; Dasmandal, Somnath; Patra, Chiranjit; Patel, Biman Kumar; Paul, Suvendu; Mahapatra, Ambikesh

2017-11-20

The interaction between a synthesized dye with proteins, bovine, and human serum albumin (BSA, HSA, respectively) under physiological conditions has been characterized in detail, by means of steady-state and time-resolved fluorescence, UV-vis absorption, and circular dichroism (CD) techniques. An extensive time-resolved fluorescence spectroscopic characterization of the quenching process has been undertaken in conjugation with temperature-dependent fluorescence quenching studies to divulge the actual quenching mechanism. From the thermodynamic observations, it is clear that the binding process is a spontaneous molecular interaction, in which van der Waals and hydrogen bonding interactions play the major roles. The UV-vis absorption and CD results confirm that the dye can induce conformational and micro-environmental changes of both the proteins. In addition, the dye binding provokes the functionality of the native proteins in terms of esterase-like activity. The average binding distance (r) between proteins and dye has been calculated using FRET. Cytotoxicity and antiviral effects of the dye have been found using Vero cell and HSV-1F virus by performing MTT assay. The AutoDock-based docking simulation reveals the probable binding location of dye within the sub-domain IIA of HSA and IB of BSA.

Optimization of process variables by response surface methodology for malachite green dye removal using lime peel activated carbon

NASA Astrophysics Data System (ADS)

Ahmad, Mohd Azmier; Afandi, Nur Syahidah; Bello, Olugbenga Solomon

2017-05-01

This study investigates the adsorptive removal of malachite green (MG) dye from aqueous solutions using chemically modified lime-peel-based activated carbon (LPAC). The adsorbent prepared was characterized using FTIR, SEM, Proximate analysis and BET techniques, respectively. Central composite design (CCD) in response surface methodology (RSM) was used to optimize the adsorption process. The effects of three variables: activation temperature, activation time and chemical impregnation ratio (IR) using KOH and their effects on percentage of dye removal and LPAC yield were investigated. Based on CCD design, quadratic models and two factor interactions (2FI) were developed correlating the adsorption variables to the two responses. Analysis of variance (ANOVA) was used to judge the adequacy of the model. The optimum conditions of MG dye removal using LPAC are: activation temperature (796 °C), activation time (1.0 h) and impregnation ratio (2.6), respectively. The percentage of MG dye removal obtained was 94.68 % resulting in 17.88 % LPAC yield. The percentage of error between predicted and experimental results for the removal of MG dye is 0.4 %. Model prediction was in good agreement with experimental results and LPAC was found to be effective in removing MG dye from aqueous solution.

[Usefulness of systematic chromoendoscopy with a double dye staining technique for the detection of dysplasia in patients with premalignant gastric lesions].

PubMed

Yep-Gamarra, Víctor; Díaz-Vélez, Cristian; Araujo, Isis; Ginès, Àngels; Fernández-Esparrach, Gloria

2016-02-01

Premalignant gastric lesions have an increased risk to develop gastric cancer. To evaluate the usefulness of systematic endoscopy that includes chromoendoscopy with a double dye staining technique for the detection of dysplasia in patients with premalignant gastric lesions. This longitudinal, prospective study was performed in patients with gastric atrophy, intestinal metaplasia or dysplasia who were referred for endoscopy less than 6 months after the initial diagnosis. The second endoscopy was performed in three phases: phase 1, exhaustive and systematic review of the mucosa with photographic documentation and biopsies of suspicious areas; phase 2, chromoendoscopy with a double dye staining technique using acetic acid 1.2% and indigo carmine 0.5%; phase 3, topographic mapping and random biopsies. A total of 50 patients were included. Nine (18%) had atrophic gastritis, 38 (76%) had intestinal metaplasia, and 3 (6%) had low-grade dysplasia. Systematic endoscopy with chromoendoscopy using a double dye staining technique detected more patients with dysplasia (9 versus 3, p<.05), and a larger number of biopsies with the diagnosis of dysplasia were obtained. This occurred for visible (6 vs. 0, p<.05) and non-visible lesions (6 vs. 3, p=NS). In one patient, initial low-grade dysplasia was not detected again in the systematic endoscopy, giving a global endoscopic performance for the detection of lesions of 92%. Patients with premalignant gastric lesions have synchronous lesions with greater histological severity, which are detected when systematic endoscopy is conducted with indigo carmine dye added to acetic acid. Copyright © 2015 Elsevier España, S.L.U. and AEEH y AEG. All rights reserved.

Degradation of Acid Blue 25 in aqueous media using 1700kHz ultrasonic irradiation: ultrasound/Fe(II) and ultrasound/H(2)O(2) combinations.

PubMed

Ghodbane, Houria; Hamdaoui, Oualid

2009-06-01

In this work, the sonolytic degradation of an anthraquinonic dye, C.I. Acid Blue 25 (AB25), in aqueous phase using high frequency ultrasound waves (1700kHz) for an acoustic power of 14W was investigated. The sonochemical efficiency of the reactor was evaluated by potassium iodide dosimeter, Fricke reaction and hydrogen peroxide production yield. The three investigated methods clearly show the production of oxidizing species during sonication and well reflect the sonochemical effects of high frequency ultrasonic irradiation. The effect of operational conditions such as the initial AB25 concentration, solution temperature and pH on the degradation of AB25 was studied. Additionally, the influence of addition of salts on the degradation of dye was examined. The rate of AB25 degradation was dependent on initial dye concentration, pH and temperature. Addition of salts increased the degradation of dye. Experiments conducted using distilled and natural waters demonstrated that the degradation was more efficient in the natural water compared to distilled water. To increase the efficiency of AB25 degradation, experiments combining ultrasound with Fe(II) or H(2)O(2) were conducted. Fe(II) induced the dissociation of ultrasonically produced hydrogen peroxide, leading to additional OH radicals which enhance the degradation of dye. The combination of ultrasound with hydrogen peroxide looks to be a promising option to increase the generation of free radicals. The concentration of hydrogen peroxide plays a crucial role in deciding the extent of enhancement obtained for the combined process. The results of the present work indicate that ultrasound/H(2)O(2) and ultrasound/Fe(II) processes are efficient for the degradation of AB25 in aqueous solutions by high frequency ultrasonic irradiation.

Time-Resolved Nucleic Acid Hybridization Beacons Utilizing Unimolecular and Toehold-Mediated Strand Displacement Designs.

PubMed

Massey, Melissa; Ancona, Mario G; Medintz, Igor L; Algar, W Russ

2015-12-01

Nucleic acid hybridization probes are sought after for numerous assay and imaging applications. These probes are often limited by the properties of fluorescent dyes, prompting the development of new probes where dyes are paired with novel or nontraditional luminescent materials. Luminescent terbium complexes are an example of such a material, and these complexes offer several unique spectroscopic advantages. Here, we demonstrate two nonstem-loop designs for light-up nucleic acid hybridization beacons that utilize time-resolved Förster resonance energy transfer (TR-FRET) between a luminescent Lumi4-Tb cryptate (Tb) donor and a fluorescent reporter dye, where time-resolved emission from the dye provides an analytical signal. Both designs are based on probe oligonucleotides that are labeled at their opposite termini with Tb and a fluorescent reporter dye. In one design, a probe is partially blocked with a quencher dye-labeled oligonucleotide, and target hybridization is signaled through toehold-mediated strand displacement and loss of a competitive FRET pathway. In the other design, the intrinsic folding properties of an unblocked probe are utilized in combination with a temporal mechanism for signaling target hybridization. This temporal mechanism is based on a recently elucidated "sweet spot" for TR-FRET measurements and exploits distance control over FRET efficiencies to shift the Tb lifetime within or outside the time-gated detection window for measurements. Both the blocked and unblocked beacons offer nanomolar (femtomole) detection limits, response times on the order of minutes, multiplexing through the use of different reporter dyes, and detection in complex matrices such as serum and blood. The blocked beacons offer better mismatch selectivity, whereas the unblocked beacons are simpler in design. The temporal mechanism of signaling utilized with the unblocked beacons also plays a significant role with the blocked beacons and represents a new and effective strategy for developing FRET probes for bioassays.

Assessment of the Dyeing Properties of the Pigments Produced by Talaromyces spp.

PubMed Central

Oliveira, Jorge; Sousa-Gallagher, Maria; Montañez, Julio Cesar

2017-01-01

The high production yields of pigments by Talaromyces spp. and their high thermal stability have implied that industrial application interests may emerge in the food and textile industries, as they both involve subjecting the colourants to high temperatures. The present study aimed to assess the potential application of the pigments produced by Talaromyces spp. in the textile area by studying their dyeing properties. Dyeing studies were performed on wool. The dyeing process consisted of three stages: scouring, mordanting, and dyeing. Two different mordants (alum, A; ferric chloride, F) were tested at different concentrations on fabric weight (A: 5, 10, 15%; F: 10, 20, 30%). The mordanting process had a significant effect on the final colour of the dyed fabrics obtained. The values of dyeing rate constant (k), half-time of dyeing (t1/2), and sorption kinetics behaviour were evaluated and discussed. The obtained results showed that pigments produced by Talaromyces spp. could serve as a source for the natural dyeing of wool textiles. PMID:29371555

Reuse of Textile Dyeing Effluents Treated with Coupled Nanofiltration and Electrochemical Processes

PubMed Central

Buscio, Valentina; García-Jiménez, María; Vilaseca, Mercè; López-Grimau, Victor; Crespi, Martí; Gutiérrez-Bouzán, Carmen

2016-01-01

The reactive dye Cibacron Yellow S-3R was selected to evaluate the feasibility of combining nanofiltration membranes with electrochemical processes to treat textile wastewater. Synthetic dyeing effluents were treated by means of two nanofiltration membranes, Hydracore10 and Hydracore50. Up to 98% of dye removal was achieved. The influence of salt concentration and pH on membrane treatment was studied. The best dye removal yield was achieved at pH 3 in the presence of 60 g/L of NaCl. After the membrane filtration, the concentrate containing high dye concentration was treated by means of an electrochemical process at three different current densities: 33, 83, and 166 mA/cm2. Results showed a lineal relationship between treatment time and applied current density. Both permeates and electrochemically-decoloured effluents were reused in new dyeing processes (100% of permeate and 70% of decoloured concentrates). Dyed fabrics were evaluated with respect to original dyeing. Colour differences were found to be into the acceptance range. PMID:28773614

Effect of TiO2 nanoparticles on some photophysical characteristics of ketocyanine dyes.

PubMed

Thipperudrappa, Javuku; Raghavendra, U P; Basanagouda, Mahantesha

2017-11-01

The effect of titanium dioxide (TiO 2 ) nanoparticles (NPs) on photophysical characteristics of 2,5-di[(E)-1-(4-dimethylaminophenyl) methylidine]-1-cyclopentanone (2,5-DMAPMC) and 2,5-di[(E)-1-(4-diethylaminophenyl)methylidine]-1-cyclopentanone (2,5-DEAPMC) ketocyanine dyes has been studied using absorption, steady-state and time-resolved fluorescence spectroscopy. The magnitudes of association constants determined based on modified absorption spectrum of dyes due to the presence of TiO 2 NPs indicate the interaction of TiO 2 NPs with dye molecules. The quenching of fluorescence intensity of dyes by TiO 2 NPs is observed and it follows linear Stern-Volmer (S-V) equation. The magnitude of quenching rate parameter suggests the involvement of static quenching mechanism. The involvement of electron transfer process in reducing fluorescence intensity of dyes has been discussed. Also, varying influence of TiO 2 NPs on two dyes is explained based on the presence of different alkyl substituent in two dyes. Copyright © 2017 John Wiley & Sons, Ltd.

Interaction and photodegradation characteristics of fluorescein dye in presence of ZnO nanoparticles.

PubMed

Bardhan, Munmun; Mandal, Gopa; Ganguly, Tapan

2011-04-01

The interaction between xanthene dye Fluorescein (Fl) and zinc oxide (ZnO) nanoparticles is investigated under physiological conditions. From the analysis of the steady state and time resolved spectroscopic studies in aqueous solution static mode is found to be responsible in the mechanism of fluorescence quenching of the dye Fl in presence of ZnO. ZnO nanoparticles are used as photocatalyst in order to degrade Fl dye. At pH 7, a maximum degradation efficiency of 44.4% of the dye has been achieved in presence of ZnO as a nanophotocatalyst and the photodegradation follows second-order kinetics.

High laser efficiency and photostability of pyrromethene dyes mediated by nonpolar solvent.

PubMed

Gupta, Monika; Kamble, Priyadarshini; Rath, M C; Naik, D B; Ray, Alok K

2015-08-10

Many pyrromethene (PM) dyes have been shown to outperform established rhodamine dyes in terms of laser efficiency in the green-yellow spectral region, but their rapid photochemical degradation in commonly used ethanol or methanol solvents continues to limit its use in high average power liquid dye lasers. A comparative study on narrowband laser efficiency and photostability of commercially available PM567 and PM597 dyes, using nonpolar n-heptane and 1,4-dioxane and polar ethanol solvents, was carried out by a constructed pulsed dye laser, pumped by the second harmonic (532 nm) radiation of a Q-switched Nd:YAG laser. Interestingly, both nonpolar solvents showed a significantly higher laser photostability (∼100 times) as well as peak efficiency (∼5%) of these PM dyes in comparison to ethanol. The different photostability of the PM dyes was rationalized by determining their triplet-state spectra and capability to generate reactive singlet oxygen (O₂1) by energy transfer to dissolved oxygen in these solvents using pulse radiolysis. Heptane is identified as a promising solvent for these PM dyes for use in high average power dye lasers, pumped by copper vapor lasers or diode-pumped solid-state green lasers.

Microbial decolorization and detoxification of emerging environmental pollutant: Cosmetic hair dyes.

PubMed

Maiti, Swati; Sinha, Sudarson Sekhar; Singh, Mukesh

2017-09-15

Since the usage of hair dyes has increased in recent time, the removal of residual dye from environment is also an emerging issue. Hair dye contains mixture of chemicals including genotoxic chemical, p-phenylenediamine (p-PD or PPD). The present study reports bioremediation of hair dye using bacteria isolated from saloon effluent. Sugarcane bagasse powder (SBP) was used as a source of nutrient and surface for bacterial growth. The 16S rDNA sequencing confirmed the isolate as Enterobacter cloacae which was designated as DDB I. The decolourization of dye was studied using UV-vis spectrophotometer. The detoxification study was conducted on microbes isolated from fresh ponds using well diffusion assay. The 1mg/ml of dye was effectively decolourised within 18h of DDB I treatment in the minimal medium containing 30mg/ml of SBP. Copyright © 2017 Elsevier B.V. All rights reserved.

Off-resonant third-order optical nonlinearities of squarylium and croconium dyes

NASA Astrophysics Data System (ADS)

Li, Zhongyu; Xu, Song; Niu, Lihong; Zhang, Zhi; Chen, Zihui; Zhang, Fushi

2008-01-01

The magnitude and dynamic response of the third-order optical nonlinearities of squarylium and croconium dyes in methanol solution were measured by femtosecond degenerate four-wave mixing (DFWM) technique at 800 nm. Ultrafast nonlinear optical responses have been observed, and the magnitude of the second-order hyperpolarizabilities was evaluated to be 5.80 × 10 -31 esu for the squarylium dye and 8.69 × 10 -31 esu for the croconium dye, respectively. The large optical nonlinearities of the dyes can be attributed to their rigid and intramolecular charge transfer structure, and the instantaneous NLO responses of dyes are shorter than the experimental time resolution (50 fs), which is mainly contributed from the electron delocalization. The fast nonlinear response and large third-order optical nonlinearities show that the studied squarylium and croconium dyes might a kind of promising materials for the applications in all-optical switching and modulator.

Biodecolorization of a food azo dye by the deep sea Dermacoccus abyssi MT1.1(T) strain from the Mariana Trench.

PubMed

Lang, Weeranuch; Sirisansaneeyakul, Sarote; Martins, Lígia O; Ngiwsara, Lukana; Sakairi, Nobuo; Pathom-aree, Wasu; Okuyama, Masayuki; Mori, Haruhide; Kimura, Atsuo

2014-01-01

This study reports the characterization of the ability of Dermacoccus spp. isolated from the deepest point of the world's oceans for azo dye decolorization. A detailed investigation of Dermacoccus abyssi MT1.1(T) with respect to the azoreductase activity and enzymatic mechanism as well as the potential role of the bacterial strain for biocleaning of industrial dye baths is reported. Resting cells with oxygen-insensitive azoreductase resulted in the rapid decolorization of the polysulfonated dye Brilliant Black BN (BBN) which is a common food colorant. The highest specific decolorization rate (vs) was found at 50 °C with a moderately thermal tolerance for over 1 h. Kinetic analysis showed the high rates and strong affinity of the enzymatic system for the dye with a Vmax = 137 mg/g cell/h and a Km = 19 mg/L. The degradation of BBN produces an initial orange intermediate, 8-amino-5-((4-sulfonatophenyl)diazenyl)naphthalene-2-sulfonic acid, identified by mass spectrometry which is later converted to 4-aminobenzene sulfonic acid. Nearly 80% of the maximum vs is possible achieved in resting cell treatment with the salinity increased up to 5.0% NaCl in reaction media. Therefore, this bacterial system has potential for dye decolorization bioprocesses occurring at high temperature and salt concentrations e.g. for cleaning dye-containing saline wastewaters. Copyright © 2013 Elsevier Ltd. All rights reserved.

Physical-chemical characterization of the textile dye Azo Ab52 degradation by corona plasma

NASA Astrophysics Data System (ADS)

Gómez, A.; Torres-Arenas, A. J.; Vergara-Sánchez, J.; Torres, C.; Reyes, P. G.; Martínez, H.; Saldarriaga-Noreña, Hugo

2017-10-01

This work characterizes the degradation of the textile dye azo Acid Black 52 by measuring several physical and chemical parameters. A corona plasma was created at atmospheric pressure and applied on the liquid-air interface of water samples containing the dye. 1.0 mM of ferrous sulfate (FeSO4) was added to 1.0 mM dye solution, for a total volume of 250 mL. For each treatment, a number of parameters were quantified. These were voltage, current, temperature, loss of volume, pH, electrical conductivity, concentration, optical mission spectra, chemical oxygen demand (COD), total organic carbon (TOC), and the removal ratio. Because of the increase in the sample temperature, the volume lost by evaporation was explored. The results show that the efficiency of the dye degradation by plasma is a function of treatment time. Moreover, the reactive concentration of FeSO4 and the exposition time of the plasma were varied at a constant volume, leading to the determination of the concentrations and optimal times. Considering the degradation and removal parameters, at the maximum treated time of 80 min, it found that COD was of 96.36%, TOC of 93.93%, and the removal ratio of 97.47%.

Imaging the Ultrafast Photoelectron Transfer Process in Alizarin-TiO2.

PubMed

Gomez, Tatiana; Hermann, Gunter; Zarate, Ximena; Pérez-Torres, Jhon Fredy; Tremblay, Jean Christophe

2015-07-30

In this work, we adopt a quantum mechanical approach based on time-dependent density functional theory (TDDFT) to study the optical and electronic properties of alizarin supported on TiO2 nano-crystallites, as a prototypical dye-sensitized solar cell. To ensure proper alignment of the donor (alizarin) and acceptor (TiO2 nano-crystallite) levels, static optical excitation spectra are simulated using time-dependent density functional theory in response. The ultrafast photoelectron transfer from the dye to the cluster is simulated using an explicitly time-dependent, one-electron TDDFT ansatz. The model considers the δ-pulse excitation of a single active electron localized in the dye to the complete set of energetically accessible, delocalized molecular orbitals of the dye/nano-crystallite complex. A set of quantum mechanical tools derived from the transition electronic flux density is introduced to visualize and analyze the process in real time. The evolution of the created wave packet subject to absorbing boundary conditions at the borders of the cluster reveal that, while the electrons of the aromatic rings of alizarin are heavily involved in an ultrafast charge redistribution between the carbonyl groups of the dye molecule, they do not contribute positively to the electron injection and, overall, they delay the process.

Determining the exact number of dye molecules attached to colloidal CdSe/ZnS quantum dots in Förster resonant energy transfer assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaiser, Uwe; Jimenez de Aberasturi, Dorleta; Vázquez-González, Margarita

2015-01-14

Semiconductor quantum dots functionalized with organic dye molecules are important tools for biological sensor applications. Energy transfer between the quantum dot and the attached dyes can be utilized for sensing. Though important, the determination of the real number of dye molecules attached per quantum dot is rather difficult. In this work, a method will be presented to determine the number of ATTO-590 dye molecules attached to CdSe/ZnS quantum dots based on time resolved spectral analysis. The energy transfer from the excited quantum dot to the attached ATTO-590 dye leads to a reduced lifetime of the quantum dot's excitons. The highermore » the concentration of dye molecules, the shorter the excitonic lifetime becomes. However, the number of dye molecules attached per quantum dot will vary. Therefore, for correctly explaining the decay of the luminescence upon photoexcitation of the quantum dot, it is necessary to take into account the distribution of the number of dyes attached per quantum dot. A Poisson distribution of the ATTO-590 dye molecules not only leads to excellent agreement between experimental and theoretical decay curves but also additionally yields the average number of dye molecules attached per quantum dot. In this way, the number of dyes per quantum dot can be conveniently determined.« less

Effect of electron withdrawing unit for dye-sensitized solar cell based on D-A-π-A organic dyes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwon, Dong Yuel; Chang, Dong Min; Kim, Young Sik, E-mail: youngkim@hongik.ac.kr

2014-10-15

Highlights: • To gain the red-shifted absorption spectra, withdrawing unit was substituted in dye. • By the introduction of additional withdrawing unit, LUMOs level of dye are decreased. • Decreasing LUMOs level of dye caused the red-shifted absorption spectra of dye. • Novel acceptor, DCRD, showed better photovoltaic properties than cyanoacetic acid. - Abstract: In this work, two novel D-A-π-A dye sensitizers with triarylamine as an electron donor, isoindigo and cyano group as electron withdrawing units and cyanoacetic acid and 2-(1,1-dicyanomethylene) rhodanine as an electron acceptor for an anchoring group (TICC, TICR) were designed and investigated with the ID6 dyemore » as the reference. The difference in HOMO and LUMO levels were compared according to the presence or absence of isoindigo in ID6 (TC and ID6). To gain insight into the factors responsible for photovoltaic performance, we used density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations. Owing to different LUMO levels for each acceptor, the absorption band and molar extinction coefficient of each dye was different. Among the dyes, TICR showed more red-shifted and broader absorption spectra than other dyes and had a higher molar extinction coefficient than the reference. It is expected that TICR would show better photovoltaic properties than the other dyes, including the reference dye.« less

Photochemical modification of polymeric materials and the polarization of light in ionomeric guest/host systems

NASA Astrophysics Data System (ADS)

Pan, Bo

Photochemical methods were introduced to develop important extrusion processes, through which polymers can either be functionalized or modified by altering molecular weight characteristics. Therefore, poly(methyl methacrylate) (PMMA) incorporated with a small amount of light-reactive functional groups was synthesized. These functional groups can be activated by UV irradiation in a post extrusion process to produce high molecular weight polymer and/or crosslinked polymer. Environmental stress cracking resistance of these polymers was examined and correlated to damping using dynamic mechanic analysis. To improve industrial reactive extrusion process of preparing maleic anhydride grafted polypropylene (MAR-g-PP), photografting was proposed and studied. Using benzophenone (BP) as the initiator, grafting efficiency was significantly improved compared to peroxide initiated grafting. Moreover, nearly constant conversion of maleic anhydride was observed in photografting. The high efficiency of benzophenone initiated photografting was attributed to the formation of the excited triplet state maleic anhydride. A rate constant of 6.0*109 M-1*sec-1 for the quenching of triplet state BP with MAH was obtained using laser photolysis spectroscopy. In a comparison, the hydrogen abstraction process from polypropylene by the triplet state BP molecules has a rate constant of 4.1*105 M-1*sec-1. In solution grafting with the use of benzene as the solvent, a facile triplet state energy transfer process may also occur leading to the formation of the excited triplet state MAH. Spectroscopic methods involving light were also used for the study of the guest-host interactions in polymer systems. The use of ionomers as the matrix for the oriented guest/host systems, cationic dye systems in particular, was shown to enhance polarization efficiency as well as dye uptake as comparing to conventional polymers, such as poly(vinyl alcohol). It was found that the dye molecules in carboxylated EVOH (EVOH-COONa) have higher degree of orientation than in EVOH, while polymer chain orientation is quite similar in these two polymers. The difference in the dye orientation was attributed to the ion-ion interactions between dye molecules and carboxylate groups of the modified polymer.

Theoretical studies on a new pattern of laser-driven systems: towards elucidation of direct photo-injection in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Mishima, Kenji; Yamashita, Koichi

2011-03-01

We theoretically and numerically investigated a new type of analytically solvable laser-driven systems inspired by electron-injection dynamics in dye-sensitized solar cells. The simple analytical expressions were found to be useful for understanding the difference between dye excitation and direct photo-injection occurring between dye molecule and semiconductor nanoparticles. More importantly, we propose a method for discriminating experimentally dye excitation and direct photo-injection by using time-dependent fluorescence. We found that dye excitation shows no significant quantum beat whereas the direct photo-injection shows a significant quantum beat. This work was supported by Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST) ``Development of Organic Photovoltaics toward a Low-Carbon Society,'' Cabinet Office, Japan.

Degradation of environment pollutant dyes using phytosynthesized metal nanocatalysts

NASA Astrophysics Data System (ADS)

MeenaKumari, M.; Philip, Daizy

2015-01-01

We present for the first time biogenic reduction and stabilization of gold and silver ions at room temperature using fruit juice of Punica granatum. The formation, morphology and crystalline structure of the synthesized nanoparticles are determined using UV-Visible, XRD and TEM. An attempt to reveal the partial role of phenolic hydroxyls in the reduction of Au3+ and Ag+ is done through FTIR analysis. The synthesized nanoparticles are used as potential catalysts in the degradation of a cationic phenothiazine dye, an anionic mono azo dye and a cationic fluorescent dye. The calculated values of percentage removal of dyes and the rate constants from pseudo first order kinetic data fit give a comparative study on degradation of organic dyes in presence of prepared gold and silver nanoparticles.

Local delivery of fluorescent dye for fiber-optics confocal microscopy of the living heart.

PubMed

Huang, Chao; Kaza, Aditya K; Hitchcock, Robert W; Sachse, Frank B

2014-01-01

Fiber-optics confocal microscopy (FCM) is an emerging imaging technology with various applications in basic research and clinical diagnosis. FCM allows for real-time in situ microscopy of tissue at sub-cellular scale. Recently FCM has been investigated for cardiac imaging, in particular, for discrimination of cardiac tissue during pediatric open-heart surgery. FCM relies on fluorescent dyes. The current clinical approach of dye delivery is based on systemic injection, which is associated with high dye consumption, and adverse clinical events. In this study, we investigated approaches for local dye delivery during FCM imaging based on dye carriers attached to the imaging probe. Using three-dimensional confocal microscopy, automated bench tests, and FCM imaging we quantitatively characterized dye release of carriers composed of open-pore foam only and foam loaded with agarose hydrogel. In addition, we compared local dye delivery with a model of systemic dye delivery in the isolated perfused rodent heart. We measured the signal-to-noise ratio (SNR) of images acquired in various regions of the heart. Our evaluations showed that foam-agarose dye carriers exhibited a prolonged dye release vs. foam-only carriers. Foam-agarose dye carriers allowed reliable imaging of 5-9 lines, which is comparable to 4-8 min of continuous dye release. Our study in the living heart revealed that the SNR of FCM images using local and systemic dye delivery is not different. However, we observed differences in the imaged tissue microstructure with the two approaches. Structural features characteristic of microvasculature were solely observed for systemic dye delivery. Our findings suggest that local dye delivery approach for FCM imaging constitutes an important alternative to systemic dye delivery. We suggest that the approach for local dye delivery will facilitate clinical translation of FCM, for instance, for FCM imaging during pediatric heart surgery.

Degradation kinetics of organic dyes in water by high voltage atmospheric air and modified air cold plasma.

PubMed

Pankaj, S K; Wan, Zifan; Colonna, William; Keener, Kevin M

2017-07-01

High voltage atmospheric cold plasma (HVACP) is a novel, non-thermal technology which has shown potential for degradation of various toxic components in wastewater. In this study, HVACP was used to examine the degradation kinetics of methyl red, crystal violet and fast green FCF dyes. HVACP discharge was found to be a source of reactive nitrogen and oxygen species. High voltage application completely degraded all dyes tested in less than 5 min treatment time. Plasma from modified gas (∼65% O 2 ) further reduced the treatment time by 50% vs. plasma from dry air. First order and Weibull models were fitted to the degradation data. The Weibull model was found better in explaining the degradation kinetics of all the treated dyes.

Modeling recombination processes and predicting energy conversion efficiency of dye sensitized solar cells from first principles

NASA Astrophysics Data System (ADS)

Ma, Wei; Meng, Sheng

2014-03-01

We present a set of algorithms based on solo first principles calculations, to accurately calculate key properties of a DSC device including sunlight harvest, electron injection, electron-hole recombination, and open circuit voltages. Two series of D- π-A dyes are adopted as sample dyes. The short circuit current can be predicted by calculating the dyes' photo absorption, and the electron injection and recombination lifetime using real-time time-dependent density functional theory (TDDFT) simulations. Open circuit voltage can be reproduced by calculating energy difference between the quasi-Fermi level of electrons in the semiconductor and the electrolyte redox potential, considering the influence of electron recombination. Based on timescales obtained from real time TDDFT dynamics for excited states, the estimated power conversion efficiency of DSC fits nicely with the experiment, with deviation below 1-2%. Light harvesting efficiency, incident photon-to-electron conversion efficiency and the current-voltage characteristics can also be well reproduced. The predicted efficiency can serve as either an ideal limit for optimizing photovoltaic performance of a given dye, or a virtual device that closely mimicking the performance of a real device under different experimental settings.

The use of artificial neural network for modeling the decolourization of acid orange 7 solution of industrial by ozonation process

NASA Astrophysics Data System (ADS)

Fatimah, S.; Wiharto, W.

2017-02-01

Acid Orange 7 (AO7) is one of the synthetic dye in the dyeing process in the textile industry. The use of this dye can produce wastewater which will be endangered if not treated well. Ozonation method is one technique to solve this problem. Ozonation is a waste processing techniques using ozone as an oxidizing agent. Variables used in this research is the ozone concentration, the initial concentration of AO7, temperature, and pH. Based on the experimental result that the optimum value decolourization percentage is 80% when the ozone concentration is 560 mg/L, the initial concentration AO7 is 14 mg/L, the temperature is 390 °C, and pH is 7,6. Decolourization efficiency of experimental results and predictions successfully modelled by the neural network architecture. The data used to construct a neural network architecture quasi newton one step secant as many as 31 data. A comparison between the predicted results of the designed ANN models and experiment was conducted. From the modeling results obtained MAPE value of 0.7763%. From the results of this artificial neural network architecture obtained the optimum value decolourization percentage in 80,64% when the concentration of ozone is 550 mg/L, the initial concentration AO7 is 11 mg/L, the temperature is 41 °C, and the pH is 7.9.

Photocurrent enhanced by singlet fission in a dye-sensitized solar cell.

PubMed

Schrauben, Joel N; Zhao, Yixin; Mercado, Candy; Dron, Paul I; Ryerson, Joseph L; Michl, Josef; Zhu, Kai; Johnson, Justin C

2015-02-04

Investigations of singlet fission have accelerated recently because of its potential utility in solar photoconversion, although only a few reports definitively identify the role of singlet fission in a complete solar cell. Evidence of the influence of singlet fission in a dye-sensitized solar cell using 1,3-diphenylisobenzofuran (DPIBF, 1) as the sensitizer is reported here. Self-assembly of the blue-absorbing 1 with co-adsorbed oxidation products on mesoporous TiO2 yields a cell with a peak internal quantum efficiency of ∼70% and a power conversion efficiency of ∼1.1%. Introducing a ZrO2 spacer layer of thickness varying from 2 to 20 Å modulates the short-circuit photocurrent such that it is initially reduced as thickness increases but 1 with 10-15 Å of added ZrO2. This rise can be explained as being due to a reduced rate of injection of electrons from the S1 state of 1 such that singlet fission, known to occur with a 30 ps time constant in polycrystalline films, has the opportunity to proceed efficiently and produce two T1 states per absorbed photon that can subsequently inject electrons into TiO2. Transient spectroscopy and kinetic simulations confirm this novel mode of dye-sensitized solar cell operation and its potential utility for enhanced solar photoconversion.

Complementary optical and nuclear imaging of caspase-3 activity using combined activatable and radio-labeled multimodality molecular probe.

PubMed

Lee, Hyeran; Akers, Walter J; Cheney, Philip P; Edwards, W Barry; Liang, Kexian; Culver, Joseph P; Achilefu, Samuel

2009-01-01

Based on the capability of modulating fluorescence intensity by specific molecular events, we report a new multimodal optical-nuclear molecular probe with complementary reporting strategies. The molecular probe (LS498) consists of tetraazacyclododecanetetraacetic acid (DOTA) for chelating a radionuclide, a near-infrared fluorescent dye, and an efficient quencher dye. The two dyes are separated by a cleavable peptide substrate for caspase-3, a diagnostic enzyme that is upregulated in dying cells. LS498 is radiolabeled with (64)Cu, a radionuclide used in positron emission tomography. In the native form, LS498 fluorescence is quenched until caspase-3 cleavage of the peptide substrate. Enzyme kinetics assay shows that LS498 is readily cleaved by caspase-3, with excellent enzyme kinetic parameters k(cat) and K(M) of 0.55+/-0.01 s(-1) and 1.12+/-0.06 microM, respectively. In mice, the initial fluorescence of LS498 is ten-fold less than control. Using radiolabeled (64)Cu-LS498 in a controlled and localized in-vivo model of caspase-3 activation, a time-dependent five-fold NIR fluorescence enhancement is observed, but radioactivity remains identical in caspase-3 positive and negative controls. These results demonstrate the feasibility of using radionuclide imaging for localizing and quantifying the distribution of molecular probes and optical imaging for reporting the functional status of diagnostic enzymes.

Complementary optical and nuclear imaging of caspase-3 activity using combined activatable and radio-labeled multimodality molecular probe

NASA Astrophysics Data System (ADS)

Lee, Hyeran; Akers, Walter J.; Cheney, Philip P.; Edwards, W. Barry; Liang, Kexian; Culver, Joseph P.; Achilefu, Samuel

2009-07-01

Based on the capability of modulating fluorescence intensity by specific molecular events, we report a new multimodal optical-nuclear molecular probe with complementary reporting strategies. The molecular probe (LS498) consists of tetraazacyclododecanetetraacetic acid (DOTA) for chelating a radionuclide, a near-infrared fluorescent dye, and an efficient quencher dye. The two dyes are separated by a cleavable peptide substrate for caspase-3, a diagnostic enzyme that is upregulated in dying cells. LS498 is radiolabeled with 64Cu, a radionuclide used in positron emission tomography. In the native form, LS498 fluorescence is quenched until caspase-3 cleavage of the peptide substrate. Enzyme kinetics assay shows that LS498 is readily cleaved by caspase-3, with excellent enzyme kinetic parameters kcat and KM of 0.55+/-0.01 s-1 and 1.12+/-0.06 μM, respectively. In mice, the initial fluorescence of LS498 is ten-fold less than control. Using radiolabeled 64Cu-LS498 in a controlled and localized in-vivo model of caspase-3 activation, a time-dependent five-fold NIR fluorescence enhancement is observed, but radioactivity remains identical in caspase-3 positive and negative controls. These results demonstrate the feasibility of using radionuclide imaging for localizing and quantifying the distribution of molecular probes and optical imaging for reporting the functional status of diagnostic enzymes.

Single, simultaneous and consecutive biosorption of Cr(VI) and Orange II onto chemically modified masau stones.

PubMed

Albadarin, Ahmad B; Solomon, Samuel; Kurniawan, Tonni Agustiono; Mangwandi, Chirangano; Walker, Gavin

2017-12-15

Novel and low cost chemically modified masau stone (CMMS) was investigated for its biosorption of an anionic azo dye, Orange II (OII), and toxic hexavalent chromium (Cr(VI)) from aqueous systems: individually, simultaneously and consecutively. XPS and FTIR analyses indicated the introduction of quaternary-Nitrogen to the CMMS surface after activation with epichlorohydrin (etherifying agent) and diethylenetriamine (crosslinking agent). The effects of pH, contact time and initial concentration (C o ), and loading order on mechanisms of biosorption/reduction of OII and Cr(VI) onto CMMS were examined in detail. Several analytical techniques were employed to characterise the physio-chemical properties of the CMMS and determine the biosorption mechanisms. The pseudo second order and redox models were able to adequately predict the kinetics of biosorption. The Langmuir maximum OII biosorption capacity (q max ) was calculated as 136.8 mg/g for the dye onto the Cr(VI)-loaded CMMS consecutive system at C o  = 100 mg/dm 3 . The q max for the Cr(VI) system was found to be 87.32 mg/g at the same C o max. This reveals that the biosorption of OII and Cr(VI) mainly takes place via two different mechanisms i.e. hydrogen bonding and electrostatic attraction for the dye, and biosorption-coupled reduction for Cr(VI). Copyright © 2017 Elsevier Ltd. All rights reserved.

A square-wave adsorptive stripping voltammetric method for the determination of Amaranth, a food additive dye.

PubMed

Alghamdi, Ahmad H

2005-01-01

Square-wave adsorptive stripping voltammetric (AdSV) determinations of trace concentrations of the azo coloring agent Amaranth are described. The analytical methodology used was based on the adsorptive preconcentration of the dye on the hanging mercury drop electrode, followed by initiation of a negative sweep. In a pH 10 carbonate supporting electrolyte, Amaranth gave a well-defined and sensitive AdSV peak at -518 mV. The electroanalytical determination of this azo dye was found to be optimal in carbonate buffer (pH 10) under the following experimental conditions: accumulation time, 120 s; accumulation potential, 0.0 V; scan rate, 600 mV/s; pulse amplitude, 90 mV; and frequency, 50 Hz. Under these optimized conditions the AdSV peak current was proportional over the concentration range 1 x 10(-8)-1.1 x 10(-7) mol/L (r = 0.999) with a detection limit of 1.7 x 10(-9) mol/L (1.03 ppb). This analytical approach possessed enhanced sensitivity, compared with conventional liquid chromatography or spectrophotometry and it was simple and fast. The precision of the method, expressed as the relative standard deviation, was 0.23%, whereas the accuracy, expressed as the mean recovery, was 104%. Possible interferences by several substances usually present as food additive azo dyes (E110, E102), gelatin, natural and artificial sweeteners, preservatives, and antioxidants were also investigated. The developed electroanalyticals method was applied to the determination of Amaranth in soft drink samples, and the results were compared with those obtained by a reference spectrophotometric method. Statistical analysis (paired t-test) of these data showed that the results of the 2 methods compared favorably.

Simultaneous spectrophotometric determination of synthetic dyes in food samples after cloud point extraction using multiple response optimizations.

PubMed

Heidarizadi, Elham; Tabaraki, Reza

2016-01-01

A sensitive cloud point extraction method for simultaneous determination of trace amounts of sunset yellow (SY), allura red (AR) and brilliant blue (BB) by spectrophotometry was developed. Experimental parameters such as Triton X-100 concentration, KCl concentration and initial pH on extraction efficiency of dyes were optimized using response surface methodology (RSM) with a Doehlert design. Experimental data were evaluated by applying RSM integrating a desirability function approach. The optimum condition for extraction efficiency of SY, AR and BB simultaneously were: Triton X-100 concentration 0.0635 mol L(-1), KCl concentration 0.11 mol L(-1) and pH 4 with maximum overall desirability D of 0.95. Correspondingly, the maximum extraction efficiency of SY, AR and BB were 100%, 92.23% and 95.69%, respectively. At optimal conditions, extraction efficiencies were 99.8%, 92.48% and 95.96% for SY, AR and BB, respectively. These values were only 0.2%, 0.25% and 0.27% different from the predicted values, suggesting that the desirability function approach with RSM was a useful technique for simultaneously dye extraction. Linear calibration curves were obtained in the range of 0.02-4 for SY, 0.025-2.5 for AR and 0.02-4 μg mL(-1) for BB under optimum condition. Detection limit based on three times the standard deviation of the blank (3Sb) was 0.009, 0.01 and 0.007 μg mL(-1) (n=10) for SY, AR and BB, respectively. The method was successfully used for the simultaneous determination of the dyes in different food samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Development of horseradish peroxidase-based cross-linked enzyme aggregates and their environmental exploitation for bioremediation purposes.

PubMed

Bilal, Muhammad; Iqbal, Hafiz M N; Hu, Hongbo; Wang, Wei; Zhang, Xuehong

2017-03-01

In the present study, horseradish peroxidase (HRP), in-house isolated crude cocktail enzyme, from Armoracia rusticana was cross-linked using a new type of cross-linking agent, i.e., ethylene glycol-bis [succinic acid N-hydroxysuccinimide, (EG-NHS)], which is mild in nature as compared to the glutaraldehyde (GA). The HRP-immobilized cross-linked enzyme aggregates (HRP-CLEAs) were developed using a wider range of EG-NHS and notably no adverse effect was observed. In a comparative evaluation, in the case of EG-NHS, a high-level stability in the residual activity was recorded, whereas a sharp decrease was observed in the case of glutaraldehyde. Following initial cross-linker evaluation, the HRP-CLEAs were tested to investigate their bio-catalytic efficacy for bioremediation purposes using a newly developed packed bed reactor system (PBRS). A maximal of 94.26% degradation of textile-based methyl orange dye was recorded within the shortest time frame, following 91.73% degradation of basic red 9, 84.35% degradation of indigo, 81.47% degradation of Rhodamin B, and 73.6% degradation of Rhodamine 6G, respectively, under the same working environment. Notably, the HRP-CLEAs retained almost 60% of its original activity after methyl orange dye degradation in seven consecutive cycles using PBRS. Furthermore, after HRP-CLEAs-mediated treatment in the PBRS, a significant toxicity reduction in the dye samples was recorded as compared to their pristine counterparts. In conclusion, the results suggest that the newly developed HRP-CLEAs have a great potential for industrial exploitation, to tackle numerous industrial dye-based emergent pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Adsorption of allura red dye by cross-linked chitosan from shrimp waste.

PubMed

Sánchez-Duarte, Reyna G; Sánchez-Machado, Dalia I; López-Cervantes, Jaime; Correa-Murrieta, Ma A

2012-01-01

The present study was designed to evaluate the chitosan, which has been obtained by deacetylation of chitin, as a biosorbent. The chitin was isolated from fermented shrimp waste by an important local industrial food biopolymer. The aim of this work was the characterization of chitosan and preparation of cross-linked chitosan- tripolyphosphate (chitosan-TPP) beads for the removal of allura red food dye from aqueous solutions. Conditions of batch adsorption such as pH, time and adsorbent dose were examined. The effectiveness of cross-linked chitosan beads for dye removal was found to be higher for pH 2 (98%, percentage of dye removal) and tends to decrease at pHs of 3 to 11 (up to 49%). The values of percentage removal show that the adsorption capacity increases with time of contact and dosage of chitosan-TPP, but red dye adsorption is mainly influenced by pH level. The cross-linked chitosan-TPP beads can significantly adsorb allura red monoazo dye from aqueous solutions even at acidic pHs unlike raw chitosan beads that tend to dissolve in acidic solutions. Consequently, this modified chitosan has characteristics that allow minimization of environmental pollution and widening the valorization of shrimp waste.

Natural dyeing and UV protection of plasma treated cotton

NASA Astrophysics Data System (ADS)

Gorjanc, Marija; Mozetič, Miran; Vesel, Alenka; Zaplotnik, Rok

2018-03-01

Raw cotton fabrics have been exposed to low-pressure non-equilibrium gaseous plasma to improve the adsorption of natural dyes as well as ultraviolet (UV) protection factor. Plasma created in a glass tube by an electrodeless radiofrequency (RF) discharge was created either in oxygen or ammonia at the pressure of 50 Pa to stimulate formation of oxygen and nitrogen groups, respectively. The type and concentration of functional groups was determined by X-ray photoelectron spectroscopy (XPS) and morphological modifications by scanning electron microscopy (SEM). The colour yield for curcumin dye was improved significantly for samples treated with ammonia plasma what was explained by bonding of the dye to surface of amino groups. Contrary, the yield decreased when oxygen plasma treatment was applied due to the negatively charged surface that repels the negatively charged dye molecules. The effect was even more pronounced when using green tea extract as the colouring agent. The colour difference between the untreated and ammonia plasma treated sample increased linearly with plasma treatment time reaching the factor of 3.5 for treatment time of 300 s. The ultraviolet protection factor (UPF) was over 50 indicating excellent protection due to improved adsorption of the dye on the ammonia plasma treated samples.

Photo-physical and structural studies of some synthesized arylazoquinoline dyes

NASA Astrophysics Data System (ADS)

Ghanadzadeh Gilani, A.; Taghvaei, V.; Moradi Rufchahi, E.; Mirzaei, M.

2017-10-01

This study presents the spectral and structure characteristics of seven azoquinoline dyes with different substituents and their new methylated counterparts for the first time, where some compounds are newly synthesized. The solvatochromic, tautomeric, halochromic, and dichroic behavior of the compounds were studied by electronic spectroscopy in various media. The different types of media were ordinary, multifunctional, and ordered liquids. The experiments were extended to include under acidic or basic conditions. The orientational behavior of the azo dye-doped liquid crystals was studied, and it was established that the azo form is the main species in high polar anisotropic media. The multi-parameter polarity scales were used to correlate the spectral data. Influence of acid and base on the absorption spectra of the dyes was also examined. Ionization constants for these dyes were determined in ethanol-water media. As a result, at the high dye concentrations, the intermolecular hydrogen bonding is more stable than the intra-molecular hydrogen bond, and therefore, the azo form is the main species in concentrated solutions. In order to provide more details, time-dependent density functional theory (TD-DFT) calculations were carried out for the representative models.

Co and Fe-catalysts supported on sepiolite: effects of preparation conditions on their catalytic behaviors in high temperature gas flow treatment of dye.

PubMed

Lin, Xiangfeng; Fang, Jian; Chen, Menglin; Huang, Zhi; Su, Chengyuan

2016-08-01

An efficient adsorbent/catalyst Co and Fe-catalysts loaded on sepiolite (Co-Fe/sepiolite) was successfully prepared for high temperature gas flow catalytic reaction by a simple impregnation method. The impact of preparation conditions (such as pH value of impregnation solution, impregnation time, calcination temperature, and time) on catalytic activity was studied. We found that the catalytic activity of Co-Fe/sepiolite was strongly influenced by all the investigated parameters. The regeneration efficiency (RE) was used to evaluate the catalytic activity. The RE is more noticeable at pH 5.0 of impregnation solution, impregnation time 18 h, calcination temperature 650 °C, and calcination time 3 h. This Co-Fe/sepiolite has great adsorption capacity in absorbing dye. It is used for an adsorbent to adsorb dye from wastewater solution under dynamic adsorption and saturated with dye, then regenerated with high temperature gas flow for adsorption/oxidation cycles. The Co-Fe/sepiolite acts as a catalyst to degrade the dye during regeneration under high temperature gas flow. Hence, the Co-Fe/sepiolite is not only an adsorbent but also a catalyst. The Co-Fe/sepiolite is more stable than sepiolite when applied in the treatment of plant's wastewater. The Co-Fe/sepiolite can be reused in adsorption-regeneration cycle. The results indicate the usability of the proposed combined process, dye adsorption on Co-Fe/sepiolite followed by the catalytic oxidation in high temperature gas flow.

Recent Advances in Heterogeneous Photocatalytic Decolorization of Synthetic Dyes

PubMed Central

Muhd Julkapli, Nurhidayatullaili; Bagheri, Samira; Bee Abd Hamid, Sharifah

2014-01-01

During the process and operation of the dyes, the wastes produced were commonly found to contain organic and inorganic impurities leading to risks in the ecosystem and biodiversity with the resultant impact on the environment. Improper effluent disposal in aqueous ecosystems leads to reduction of sunlight penetration which in turn diminishes photosynthetic activity, resulting in acute toxic effects on the aquatic flora/fauna and dissolved oxygen concentration. Recently, photodegradation of various synthetic dyes has been studied in terms of their absorbance and the reduction of oxygen content by changes in the concentration of the dye. The advantages that make photocatalytic techniques superior to traditional methods are the ability to remove contaminates in the range of ppb, no generation of polycyclic compounds, higher speed, and lower cost. Semiconductor metal oxides, typically TiO2, ZnO, SnO, NiO, Cu2O, Fe3O4, and also CdS have been utilized as photocatalyst for their nontoxic nature, high photosensitivity, wide band gap and high stability. Various process parameters like photocatalyst dose, pH and initial dye concentrations have been varied and highlighted. Research focused on surface modification of semiconductors and mixed oxide semiconductors by doping them with noble metals (Pt, Pd, Au, and Ag) and organic matter (C, N, Cl, and F) showed enhanced dye degradation compared to corresponding native semiconductors. This paper reviews recent advances in heterogeneous photocatalytic decolorization for the removal of synthetic dyes from water and wastewater. Thus, the main core highlighted in this paper is the critical selection of semiconductors for photocatalysis based on the chemical, physical, and selective nature of the poisoning dyes. PMID:25054183

Sorption isotherms, kinetic and optimization process of amino acid proline based polymer nanocomposite for the removal of selected textile dyes from industrial wastewater.

PubMed

Raghunath, Sharista; Anand, K; Gengan, R M; Nayunigari, Mithil Kumar; Maity, Arjun

2016-12-01

In this article, adsorption and kinetic studies were carried out on three textile dyes, namely Reactive Blue 222 (RB 222), Reactive Red 195 (RR 195) and Reactive Yellow 145 (RY 145). The dyes studied in a mixture were adsorbed under various conditions onto PRO-BEN, a bentonite modified with a new cationic proline polymer (l-proline-epichlorohydrin polymer). The proline polymer was characterized by 1 H NMR, Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS) and TEM. The PRO-BEN composite was characterized by FT-IR, dynamic light scattering (DLS) (zeta potential), TEM imaging, SEM/EDX and X-ray photoelectron spectroscopy (characterize the binding energy). During adsorption studies, factors involving pH, temperature, the initial concentrations of the dyes and the quantity of PRO-BEN used during adsorption were established. The results revealed that the adsorption mechanism was categorized by the Langmuir type 1 isotherm. The adsorption data followed the pseudo-second order kinetic model. The intraparticle diffusion model indicated that adsorption did not only depend on the intraparticle diffusion of the dyes. The thermodynamic parameters verified that the adsorption process was spontaneous and exothermic. The Gibbs free energy values indicated that physisorption had occurred. Successful adsorption of dyes from an industrial effluent was achieved. Desorption studies concluded that PRO-BEN desorbed the dyes better than alumina. This can thereby be viewed as a recyclable remediation material. The PRO-BEN composite could be a cost efficient alternative towards the removal of organic dyes in wastewater treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

Calibration procedures for the quantitative determination of membrane potential in human cells using anionic dyes.

PubMed

Klapperstück, Thomas; Glanz, Dagobert; Hanitsch, Stefan; Klapperstück, Manuela; Markwardt, Fritz; Wohlrab, Johannes

2013-07-01

Quantitative determinations of the cell membrane potential of lymphocytes (Wilson et al., J Cell Physiol 1985;125:72-81) and thymocytes (Krasznai et al., J Photochem Photobiol B 1995;28:93-99) using the anionic dye DiBAC4 (3) proved that dye depletion in the extracellular medium as a result of cellular uptake can be negligible over a wide range of cell densities. In contrast, most flow cytometric studies have not verified this condition but rather assumed it from the start. Consequently, the initially prepared extracellular dye concentration has usually been used for the calculation of the Nernst potential of the dye. In this study, however, external dye depletion could be observed in both large IGR-1 and small LCL-HO cells under experimental conditions, which have often been applied routinely in spectrofluorimetry and flow cytometry. The maximum cell density at which dye depletion could be virtually avoided was dependent on cell size and membrane potential and definitely needed to be taken into account to ensure reliable results. In addition, accepted calibration procedures based on the partition of sodium and potassium (Goldman-Hodgkin-Katz equation) or potassium alone (Nernst equation) were performed by flow cytometry on cell suspensions with an appropriately low cell density. The observed extensive lack of concordance between the correspondingly calculated membrane potential and the equilibrium potential of DiBAC4 (3) revealed that these methods require the additional measurement of cation parameters (membrane permeability and/or intracellular concentration). In contrast, due to the linear relation between fluorescence and low DiBAC4 (3) concentrations, the Nernst potential of the dye for totally depolarized cells can be reliably used for calibration with an essentially lower effort and expense. Copyright © 2013 International Society for Advancement of Cytometry.

Photodynamic Inactivation of Acinetobacter baumannii Using Phenothiazinium Dyes: In Vitro and In Vivo Studies

PubMed Central

Ragàs, Xavier; Dai, Tianhong; Tegos, George P.; Agut, Montserrat; Nonell, Santi; Hamblin, Michael R.

2010-01-01

Background and Objective Phenothiazinium dyes have been reported to be effective photosensitizers inactivating a wide range of microorganisms in vitro after illumination with red light. However, their application in vivo has not extensively been explored. This study evaluates the bactericidal activity of phenothiazinium dyes against multidrug-resistant Acinetobacter baumannii both in vitro and in vivo. Study Design/Materials and Methods We report the investigation of toluidine blue O, methylene blue, 1,9-dimethylmethylene blue, and new methylene blue for photodynamic inactivation of multidrug-resistant A. baumannii in vitro. The most effective dye was selected to carry out in vivo studies using third-degree mouse burns infected with a bioluminescent A. baumannii strain, upon irradiation with a 652 nm noncoherent light source. The mice were imaged daily for 2 weeks to observe differences in the bioluminescence–time curve between the photodynamic therapy (PDT)-treated mice in comparison with untreated burns. Results All the dyes were effective in vitro against A. baumannii after 30 J/cm2 irradiation of 635 or 652 nm red light had been delivered, with more effective killing when the dye remained in solution. New methylene blue was the most effective of the four dyes, achieving a 3.2-log reduction of the bacterial luminescence during PDT in vivo after 360 J/cm2 and an 800 μM dye dose. Moreover, a statistically significant reduction of the area under the bioluminescence–time curve of PDT-treated mice was observed showing that the infection did not recur after PDT. Conclusions Phenothiazinium dyes, and especially new methylene blue, are potential photosensitizers for PDT to treat burns infected with multidrug-resistant A. baumannii in vivo. PMID:20583252

Formation of J-Aggregates of an Anionic Oxacarbocyanine Dye Upon Interaction with Proteins and Polyelectrolytes

NASA Astrophysics Data System (ADS)

Pronkin, P. G.; Tatikolov, A. S.

2017-05-01

J-aggregation of the anionic oxacarbocyanine dye 3,3'-di-(γ-sulfopropyl)-5,5'-diphenyl-9-ethyloxacarbocyanine betaine was studied in aqueous solutions in the presence of proteins (collagens, immunoglobulin G, serum albumins) and polyelectrolytes (polyethyleneimine, polyvinylpyrrolidone). It was found that denaturation of human serum albumin by urea stimulated J-aggregation of the dye. The dye formed two types of J-aggregates in the presence of denatured albumin and polyethyleneimine. J-aggregates formed in the presence of polyethyleneimine rearranged over time.

Single molecule diffusion and the solution of the spherically symmetric residence time equation.

PubMed

Agmon, Noam

2011-06-16

The residence time of a single dye molecule diffusing within a laser spot is propotional to the total number of photons emitted by it. With this application in mind, we solve the spherically symmetric "residence time equation" (RTE) to obtain the solution for the Laplace transform of the mean residence time (MRT) within a d-dimensional ball, as a function of the initial location of the particle and the observation time. The solutions for initial conditions of potential experimental interest, starting in the center, on the surface or uniformly within the ball, are explicitly presented. Special cases for dimensions 1, 2, and 3 are obtained, which can be Laplace inverted analytically for d = 1 and 3. In addition, the analytic short- and long-time asymptotic behaviors of the MRT are derived and compared with the exact solutions for d = 1, 2, and 3. As a demonstration of the simplification afforded by the RTE, the Appendix obtains the residence time distribution by solving the Feynman-Kac equation, from which the MRT is obtained by differentiation. Single-molecule diffusion experiments could be devised to test the results for the MRT presented in this work. © 2011 American Chemical Society

Fabrication and characterization of dye-sensitized solar cells based on natural plants

NASA Astrophysics Data System (ADS)

Gu, Peng; Yang, Dingyu; Zhu, Xinghua; Sun, Hui; Li, Jitao

2018-02-01

In this paper, the dye-sensitized solar cells (DSSCs) were fabricated based on natural dyes extracting from carrot, mulberry, purple cabbage, potato, and grapes. The ultraviolet-visible spectra suggested purple cabbage and mulberry possess better absorption at 300-550 nm. The solar cells using purple cabbage as dye achieved a conversion efficiency of 0.162% with short-circuit photocurrent density (Jsc) of 0.621 mA/cm2, open circuit voltage (Voc) of 0.541 V and fill factor (FF) of 0.484. The Infrared spectra revealed the bond of Osbnd H, Csbnd C, Csbnd O, Csbnd H were existed in purple cabbage. Finally, the optimal extraction time of dyes is also presented.

Water-soluble pH-responsive dendritic core-shell nanocarriers for polar dyes based on poly(ethylene imine).

PubMed

Xu, Shangjie; Luo, Ying; Haag, Rainer

2007-08-07

A simple general synthetic concept to build dendritic core-shell architectures with pH-labile linkers based on hyperbranched PEI cores and biocompatible PEG shells is presented. Using these dendritic core-shell architectures as nanocarriers, the encapsulation and transport of polar dyes of different sizes is studied. The results show that the acid-labile nanocarriers exhibit much higher transport capacities for dyes than unfunctionalized hyperbranched PEI. The cleavage of imine bonds and controlled release of the polar dyes revealed that weak acidic condition (pH approximately 5.0) could cleave the imine bonds linker and release the dyes up to five times faster than neutral conditions (pH = 7.4).

A photoelectric amplifier as a dye detector

USGS Publications Warehouse

Ebel, Wesley J.

1962-01-01

A dye detector, based on a modified photoelectric amplifier, has been planned, built, and tested. It was designed to record automatically the time of arrival of fluorescein dye at predetermined points in a stream system. Laboratory tests and stream trials proved the instrument to be efficient. Small changes in color can be detected in turbid or clear water. The unit has been used successfully for timing intervals of more than 17 hours; significant savings of time and manpower have resulted. Replacement of the clock, included in the original device, with a recording milliammeter increases the efficiency of the unit by contin,!ously recording changes in turbidity. The addition of this component would increase the cost from $75 to approximately $105.

Characterizing the marker-dye correction for Gafchromic(®) EBT2 film: a comparison of three analysis methods.

PubMed

McCaw, Travis J; Micka, John A; Dewerd, Larry A

2011-10-01

Gafchromic(®) EBT2 film has a yellow marker dye incorporated into the active layer of the film that can be used to correct the film response for small variations in thickness. This work characterizes the effect of the marker-dye correction on the uniformity and uncertainty of dose measurements with EBT2 film. The effect of variations in time postexposure on the uniformity of EBT2 is also investigated. EBT2 films were used to measure the flatness of a (60)Co field to provide a high-spatial resolution evaluation of the film uniformity. As a reference, the flatness of the (60)Co field was also measured with Kodak EDR2 films. The EBT2 films were digitized with a flatbed document scanner 24, 48, and 72 h postexposure, and the images were analyzed using three methods: (1) the manufacturer-recommended marker-dye correction, (2) an in-house marker-dye correction, and (3) a net optical density (OD) measurement in the red color channel. The field flatness was calculated from orthogonal profiles through the center of the field using each analysis method, and the results were compared with the EDR2 measurements. Uncertainty was propagated through a dose calculation for each analysis method. The change in the measured field flatness for increasing times postexposure was also determined. Both marker-dye correction methods improved the field flatness measured with EBT2 film relative to the net OD method, with a maximum improvement of 1% using the manufacturer-recommended correction. However, the manufacturer-recommended correction also resulted in a dose uncertainty an order of magnitude greater than the other two methods. The in-house marker-dye correction lowered the dose uncertainty relative to the net OD method. The measured field flatness did not exhibit any unidirectional change with increasing time postexposure and showed a maximum change of 0.3%. The marker dye in EBT2 can be used to improve the response uniformity of the film. Depending on the film analysis method used, however, application of a marker-dye correction can improve or degrade the dose uncertainty relative to the net OD method. The uniformity of EBT2 was found to be independent of the time postexposure.

Electroadsorption of acilan blau dye from textile effluents by using activated carbon-perlite mixtures.

PubMed

Koparal, A S; Yavuz, Y; Bakir Ogütveren, U

2002-01-01

The feasibility of the removal of dye stuffs from textile effluents by electroadsorption has been investigated. An activated carbon-perlite mixture with a ratio of 8:1 for bipolarity has been used as the adsorbent. Conventional adsorption experiments have also been conducted for comparison. A bipolar trickle reactor has been used in the electroadsorption experiments. The model wastewater has been prepared by using acilan blau dye. Initial dye concentration, bed height between the electrodes, applied potential, flowrate, and the supporting electrolyte concentration have been examined as the parameters affecting the removal efficiency. A local textile plant effluent has been treated in the optimum values of these parameters obtained from the experimental studies. Adsorption kinetics and the amount of adsorbent required to reach the maximum removal efficiency have also been investigated and mass-transfer coefficients have been calculated for adsorption and electroadsorption. The results showed that a removal efficiency of up to 100% can be achieved with energy consumption values of 1.58 kWh/m3 of wastewater treated. However, energy consumption decreases to 0.09 kWh/m3 if an exit dye concentration of 4.65 mg/L is accepted. It can be concluded from this work that this method combines all of the advantages of the activated-carbon adsorption and electrolytic methods for the removal of dyes from wastewater.

Photocatalytic degradation of Orange G dye under solar light using nanocrystalline semiconductor metal oxide.

PubMed

Thennarasu, G; Kavithaa, S; Sivasamy, A

2011-08-01

The photocatalytic degradation of Orange G (OG) dye has been investigated using synthesised nanocrystalline ZnO as a photocatalyst and sunlight as the irradiation source. The formation of ZnO prepared from its precursor was confirmed through FT-IR and powder X-ray diffraction analyses. Surface morphology was characterised by scanning electron microscope and transmission electron microscope analysis. Band gap energy of synthesised nanocrystalline ZnO was calculated using diffuse reflectance spectroscopy (DRS). Different experimental parameters such as effects of pH, dye concentrations and mass of catalyst were standardised in order to achieve complete degradation of the dye molecules under solar light irradiation. The kinetics of oxidation of OG was also studied. The complete degradation of OG was evident after 90 min of irradiation at an initial pH of 6.86. The degradation of OG was confirmed by UV-Visible spectrophotometer, high-pressure liquid chromatography, ESI-Mass and chemical oxygen demand analyses. The adsorption of dye onto catalytic surface was analysed employing model equations such as Langmuir and Freundlich isotherms, and it was found that the Langmuir isotherm model best fitted the adsorption data. The solar photodegradation of OG followed pseudo-first-order kinetics. HPLC and ESI-Mass analyses of the degraded samples suggested that the dye molecules were readily degraded under solar irradiation with nanocrystalline ZnO.

Characterization of Natural Dyes and Traditional Korean Silk Fabric by Surface Analytical Techniques

PubMed Central

Lee, Jihye; Kang, Min Hwa; Lee, Kang-Bong; Lee, Yeonhee

2013-01-01

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) are well established surface techniques that provide both elemental and organic information from several monolayers of a sample surface, while also allowing depth profiling or image mapping to be carried out. The static TOF-SIMS with improved performances has expanded the application of TOF-SIMS to the study of a variety of organic, polymeric and biological materials. In this work, TOF-SIMS, XPS and Fourier Transform Infrared (FTIR) measurements were used to characterize commercial natural dyes and traditional silk fabric dyed with plant extracts dyes avoiding the time-consuming and destructive extraction procedures necessary for the spectrophotometric and chromatographic methods previously used. Silk textiles dyed with plant extracts were then analyzed for chemical and functional group identification of their dye components and mordants. TOF-SIMS spectra for the dyed silk fabric showed element ions from metallic mordants, specific fragment ions and molecular ions from plant-extracted dyes. The results of TOF-SIMS, XPS and FTIR are very useful as a reference database for comparison with data about traditional Korean silk fabric and to provide an understanding of traditional dyeing materials. Therefore, this study shows that surface techniques are useful for micro-destructive analysis of plant-extracted dyes and Korean dyed silk fabric. PMID:28809257

Studies on Coloration and UV Protective Action of Anar Peel (Pomegranate Rind) as an Effective Natural Colorant for Cotton Khadi Fabric

NASA Astrophysics Data System (ADS)

Sinnur, H. D.; Samanta, Ashis Kumar; Verma, D. K.; Kaware, Runali

2018-06-01

Besides optimization of conditions of colour extraction from dried anar peel, effect of different single and double mordants, dyeing process variables and UV protective action of anar peels (pomegranate rind i.e. Punica granatum L.) as a natural colourant is studied in this work. Mordants used are potash alum, aluminium sulphate and stannous chloride (as metallic salt mordant) and harda (i.e., myrobolan as natural mordant) from natural source. Relevant results indicate that 50:50 ratio of harda plus potash aluminium sulphate at overall 15% application level offers maximum K/S value and overall good colour fastness than any other combination. After finalizing the mordants, dyeing process variables were studied for standardization of conditions for dyeing cotton khadi fabric with aqueous extract of pomegranate rind. The results indicate that standardized conditions for dyeing are (a) dyeing time : 60 min, (b) dyeing temperature: 80 °C, (c) dye bath MLR : 1:30, (d) dye bath pH : 9.0, (e) max dye concentration : 20% and (f) common salt : 3%. Studies of FTIR, UV scan, Atomic Absorption Spectrophotometry (AAS) and UV Protection Factor (UPF) characters show a medium to good level of ultraviolet protection. Corresponding reaction mechanism amongst mordant/fibre and dye forming giant complex is also reported.

Studies on Coloration and UV Protective Action of Anar Peel (Pomegranate Rind) as an Effective Natural Colorant for Cotton Khadi Fabric

NASA Astrophysics Data System (ADS)

Sinnur, H. D.; Samanta, Ashis Kumar; Verma, D. K.; Kaware, Runali

2017-10-01

Besides optimization of conditions of colour extraction from dried anar peel, effect of different single and double mordants, dyeing process variables and UV protective action of anar peels (pomegranate rind i.e. Punica granatum L.) as a natural colourant is studied in this work. Mordants used are potash alum, aluminium sulphate and stannous chloride (as metallic salt mordant) and harda (i.e., myrobolan as natural mordant) from natural source. Relevant results indicate that 50:50 ratio of harda plus potash aluminium sulphate at overall 15% application level offers maximum K/S value and overall good colour fastness than any other combination. After finalizing the mordants, dyeing process variables were studied for standardization of conditions for dyeing cotton khadi fabric with aqueous extract of pomegranate rind. The results indicate that standardized conditions for dyeing are (a) dyeing time : 60 min, (b) dyeing temperature: 80 °C, (c) dye bath MLR : 1:30, (d) dye bath pH : 9.0, (e) max dye concentration : 20% and (f) common salt : 3%. Studies of FTIR, UV scan, Atomic Absorption Spectrophotometry (AAS) and UV Protection Factor (UPF) characters show a medium to good level of ultraviolet protection. Corresponding reaction mechanism amongst mordant/fibre and dye forming giant complex is also reported.

Screening of freshwater fungi for decolorizing multiple synthetic dyes.

PubMed

Yang, Panpan; Shi, Wenxiao; Wang, Hongkai; Liu, Hongmei

The biodegradation of synthetic dyes by fungi is emerging as an effective and promising approach. In the present study, freshwater fungal strains isolated from submerged woods were screened for the decolorization of 7 synthetic dyes. Subsequently, 13 isolates with high decolorization capability were assessed in a liquid system; they belonged to 9 different fungal species. Several strains exhibited a highly effective decolorization of multiple types of dyes. New absorbance peaks appeared after the treatment with 3 fungal strains, which suggests that a biotransformation process occurred through fungal biodegradation. These results showed the unexploited and valuable capability of freshwater fungi for the treatment of dye-containing effluents. The ability of certain fungi to decolorize dyes is reported here for the first time. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Photocatalytic degradation of model textile dyes in wastewater using ZnO as semiconductor catalyst.

PubMed

Chakrabarti, Sampa; Dutta, Binay K

2004-08-30

Semiconductor photocatalysis often leads to partial or complete mineralization of organic pollutants. Upon irradiation with UV/visible light, semiconductors catalyze redox reactions in presence of air/O2 and water. Here, the potential of a common semiconductor, ZnO, has been explored as an effective catalyst for the photodegradation of two model dyes: Methylene Blue and Eosin Y. A 16 W lamp was the source of UV-radiation in a batch reactor. The effects of process parameters like, catalyst loading, initial dye concentration, airflow rate, UV-radiation intensity, and pH on the extent of photo degradation have been investigated. Substantial reduction of COD, besides removal of colour, was also achieved. A rate equation for the degradation based on Langmuir-Hinshelwood model has been proposed.

Insights into the Mechanism of a Covalently Linked Organic Dye-Cobaloxime Catalyst System for Dye-Sensitized Solar Fuel Devices.

PubMed

Pati, Palas Baran; Zhang, Lei; Philippe, Bertrand; Fernández-Terán, Ricardo; Ahmadi, Sareh; Tian, Lei; Rensmo, Håkan; Hammarström, Leif; Tian, Haining

2017-06-09

A covalently linked organic dye-cobaloxime catalyst system based on mesoporous NiO is synthesized by a facile click reaction for mechanistic studies and application in a dye-sensitized solar fuel device. The system is systematically investigated by photoelectrochemical measurements, density functional theory, time-resolved fluorescence, transient absorption spectroscopy, and photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer process to reduce the catalyst. Moreover, the dye adopts different structures with different excited state energies, and excitation energy transfer occurs between neighboring molecules on the semiconductor surface. The photoelectrochemical experiments also show hydrogen production by this system. The axial chloride ligands of the catalyst are released during photocatalysis to create the active sites for proton reduction. A working mechanism of the dye-catalyst system on the photocathode is proposed on the basis of this study. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Iodinated Al(III)-based phthalocyanines are promising sensitizers for dye-sensitized solar cells; a theoretical comparison between Zn(II), Mg(II), and Al(III)-based phthalocyanine sensitizers.

PubMed

Yang, Li-Na; Sun, Zhu-Zhu; Chen, Shi-Lu; Li, Ze-Sheng

2014-02-24

To design efficient dyes for dye-sensitized solar cells (DSSCs), using a Zn-coordinated phthalocyanine (TT7) as the prototype, a series of phthalocyanine dyes (Pcs) with different metal ions and peripheral/axial groups have been investigated by means of density functional theory (DFT) and time-dependent DFT (TDDFT) methods. Computational results show that the iodinated Al-based dye with a peripheral amino group (Al-I-NH2-Pc) exhibits the largest redshift in the maximum absorbance (λ(max)). In addition, Al-based dyes have appropriate energy-level arrangements of frontier orbitals to keep excellent balance between electron injection and regeneration of oxidized dyes. Further, it has been found that the intermolecular π-staking interaction in Al-I-Pc molecules is weaker than the other metal-based Pcs, which may effectively reduce dye aggregation on the semi-conductor surface. All these results suggest iodinated Al-based Pcs (Al-I-Pcs) to be potentially promising sensitizers in DSSCs. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ozonation of exhausted dark shade reactive dye bath for reuse.

PubMed

Sundrarajan, M; Vishnu, G; Joseph, Kurian

2006-10-01

Exhausted reactive dye bath of dark shades were collected from cotton knit wear dyeing units in Tirupur. Ozonation was conducted in a column reactor system fed with ozone at the rate of 0.16 g/min to assess its efficiency in reducing the color, chemical oxygen demand and total organic carbon. The potential of the decolorized dye bath for its repeated reuse was also analyzed. The results from the reusability studies indicate that the dyeing quality was not affected by the reuse of decolorized dye bath for two successive cycles. Complete decolorization of the effluent was achieved in 60 minutes contact time at an ozone consumption of 183 mg/L for Red, 175 for Navy Blue and 192 for Green shades respectively. The corresponding COD removal was 60%, 54% and 63% for the three shades while TOC removal efficiency was 59%, 55% and 62% respectively. It is concluded that ozonation is efficient in decolorization of exhausted dye bath effluents containing conventional reactive dyes. However, the corresponding removal of COD from the textile effluent was not significant.

Benzo[a]carbazole-Based Donor-π-Acceptor Type Organic Dyes for Highly Efficient Dye-Sensitized Solar Cells.

PubMed

Qian, Xing; Zhu, Yi-Zhou; Chang, Wen-Ying; Song, Jian; Pan, Bin; Lu, Lin; Gao, Huan-Huan; Zheng, Jian-Yu

2015-05-06

A novel class of metal-free organic dyes based on benzo[a]carbazole have been designed, synthesized, and used in dye-sensitized solar cells for the first time. These types of dyes consisted of a cyanoacrylic acid moiety as the electron acceptor/anchoring group and different electron-rich spacers such as thiophene (JY21), furan (JY22), and oligothiophene (JY23) as the π-linkers. The photophysical, electrochemical, and photovoltaic properties, as well as theoretical calculations of these dyes were investigated. The photovoltaic performances of these dyes were found to be highly relevant to the π-conjugated linkers. In particular, dye JY23 exhibited a broad IPCE response with a photocurrent signal up to about 740 nm covering the most region of the UV-visible light. A DSSC based on JY23 showed the best photovoltaic performance with a Jsc of 14.8 mA cm(-2), a Voc of 744 mV, and a FF of 0.68, achieving a power conversion efficiency of 7.54% under standard AM 1.5 G irradiation.

Oxidation of Levafix CA reactive azo-dyes in industrial wastewater of textile dyeing by electro-generated Fenton's reagent.

PubMed

El-Desoky, Hanaa S; Ghoneim, Mohamed M; El-Sheikh, Ragaa; Zidan, Naglaa M

2010-03-15

The indirect electrochemical removal of pollutants from effluents has become an attractive method in recent years. Removal (decolorization and mineralization) of Levafix Blue CA and Levafix Red CA reactive azo-dyes from aqueous media by electro-generated Fenton's reagent (Fe(2+)/H(2)O(2)) using a reticulated vitreous carbon cathode and a platinum gauze anode was optimized. Progress of oxidation (decolorization and mineralization) of the investigated azo-dyes with time of electro-Fenton's reaction was monitored by UV-visible absorbance measurements, Chemical oxygen demand (COD) removal and HPLC analysis. The results indicated that the electro-Fenton's oxidation system is efficient for treatment of such types of reactive dyes. Oxidation of each of the investigated azo-dyes by electro-generated Fenton's reagent up to complete decolorization and approximately 90-95% mineralization was achieved. Moreover, the optimized electro-Fenton's oxidation was successfully applied for complete decolorization and approximately 85-90% mineralization of both azo-dyes in real industrial wastewater samples collected from textile dyeing house at El-Mahalla El-Kobra, Egypt. (c) 2009 Elsevier B.V. All rights reserved.

Time of travel and dispersion of solutes in a 36.4-mile reach of the North Platte River downstream from Casper, Wyoming

USGS Publications Warehouse

Armentrout, G.W.; Larson, L.R.

1984-01-01

Time-of-travel and dispersion measurements made during a dye study November 7-8, 1978, are presented for a reach of the North Platte River from Casper, Wyo., to a bridge 2 miles downstream from below the Dave Johnston Power Plant. Rhodamine WT dye was injected into the river at Casper, and the resultant dye cloud was traced by sampling as it moved downstream. Samples were taken in three equal-flow sections of the river 's lateral transect at three sites, then analyzed in a fluorometer. The flow in the river was 940 cubic feet per second. The data consist of measured stream mileages and time, distance, and concentration graphs of the dye cloud. The peak concentration traveled through the reach in 24 hours, averaging 1.5 miles per hour; the leading edge took about 22 hours, averaging 1.7 miles per hour; and the trailing edge took 35 hours, averaging 1.0 mile per hour. Data from this study were compared with methods for estimating time of travel for a range of stream discharges.

Site-Dependent Fluorescence Decay of Malachite Green Doped in Onion Cell

NASA Astrophysics Data System (ADS)

Nakatsuka, Hiroki; Sekine, Masaya; Suzuki, Yuji; Hattori, Toshiaki

1999-03-01

Time-resolved fluorescence measurements of malachite green dye moleculesdoped in onion cells were carried out.The fluorescence decay time was dependent on the individual cell and on theposition of the dye in a cell, which reflect the microscopic dynamics of each boundsite.Upon cooling, the decay time increased and this increase was accelerated ataround the freezing point of the onion cell.

[Contents mensuration of total alkaloid in Uncaria rhynchophylla by acid dye colorimetry].

PubMed

Zeng, Chang-qing; Luo, Bei-liang

2007-08-01

To investigate the method of determination of total alkaloids Uncaria rhynchophylla. The Contents of total Alkaloid were determined by Acid dye Colorimetry. Acid dye color conditions: pH3.6 buffer 5.0 ml, bromocresol green liquid 5.0 ml; chloroform extraction three times, each time was exeracted for 2 minutes, put it aside for at least 5 minutes for the determination of the best method. Rhynchophylline 6.018 microg - 108.324 microg in the linear range, Recoveriys rate was 97.19%, RSD was 1.34% (n = 6). The method is simple, highly sensitive and reproducible.

Probing the Ca(2+) switch of the neuronal Ca(2+) sensor GCAP2 by time-resolved fluorescence spectroscopy.

PubMed

Kollmann, Heiko; Becker, Simon F; Shirdel, Javid; Scholten, Alexander; Ostendorp, Anna; Lienau, Christoph; Koch, Karl-Wilhelm

2012-06-15

We report fluorescence lifetime and rotational anisotropy measurements of the fluorescent dye Alexa647 attached to the guanylate cyclase-activating protein 2 (GCAP2), an intracellular myristoylated calcium sensor protein operating in photoreceptor cells. By linking the dye to different protein regions critical for monitoring calcium-induced conformational changes, we could measure fluorescence lifetimes and rotational correlation times as a function of myristoylation, calcium, and position of the attached dye, while GCAP2 was still able to regulate guanylate cyclase in a Ca(2+)-sensitive manner. We observe distinct site-specific variations in the fluorescence dynamics when externally changing the protein conformation. A clear reduction in fluorescence lifetime suggests that in the calcium-free state a dye marker in amino acid position 131 senses a more hydrophobic protein environment than in position 111. Saturating GCAP2 with calcium increases the fluorescence lifetime and hence leads to larger exposure of position 111 to the solvent and at the same time to a movement of position 131 into a hydrophobic protein cleft. In addition, we find distinct, biexponential anisotropy decays reflecting the reorientational motion of the fluorophore dipole and the dye/protein complex, respectively. Our experimental data are well described by a "wobbling-in-a-cone" model and reveal that for dye markers in position 111 of the GCAP2 protein both addition of calcium and myristoylation results in a pronounced increase in orientational flexibility of the fluorophore. Our results provide evidence that the up-and-down movement of an α-helix that is situated between position 111 and 131 is a key feature of the dynamics of the protein-dye complex. Operation of this piston-like movement is triggered by the intracellular messenger calcium.

Oxazine dye-conjugated dna oligonucleotides: Förster resonance energy transfer in view of molecular dye-DNA interactions.

PubMed

Kupstat, Annette; Ritschel, Thomas; Kumke, Michael U

2011-12-21

In this work, the photophysical properties of two oxazine dyes (ATTO 610 and ATTO 680) covalently attached via a C6-amino linker to the 5'-end of short single-stranded as well as double-stranded DNA (ssDNA and dsDNA, respectively) of different lengths were investigated. The two oxazine dyes were chosen because of the excellent spectral overlap, the high extinction coefficients, and the high fluorescence quantum yield of ATTO 610, making them an attractive Förster resonance energy transfer (FRET) pair for bioanalytical applications in the far-red spectral range. To identify possible molecular dye-DNA interactions that cause photophysical alterations, we performed a detailed spectroscopic study, including time-resolved fluorescence anisotropy and fluorescence correlation spectroscopy measurements. As an effect of the DNA conjugation, the absorption and fluorescence maxima of both dyes were bathochromically shifted and the fluorescence decay times were increased. Moreover, the absorption of conjugated ATTO 610 was spectrally broadened, and a dual fluorescence emission was observed. Steric interactions with ssDNA as well as dsDNA were found for both dyes. The dye-DNA interactions were strengthened from ssDNA to dsDNA conjugates, pointing toward interactions with specific dsDNA domains (such as the top of the double helix). Although these interactions partially blocked the dye-linker rotation, a free (unhindered) rotational mobility of at least one dye facilitated the appropriate alignment of the transition dipole moments in doubly labeled ATTO 610/ATTO 680-dsDNA conjugates for the performance of successful FRET. Considering the high linker flexibility for the determination of the donor-acceptor distances, good accordance between theoretical and experimental FRET parameters was obtained. The considerably large Förster distance of ~7 nm recommends the application of this FRET pair not only for the detection of binding reactions between nucleic acids in living cells but also for monitoring interactions of larger biomolecules such as proteins.

Statistical analysis and mathematical modeling of a tracer test on the Santa Clara River, Ventura County, California

USGS Publications Warehouse

Paybins, Katherine S.; Nishikawa, Tracy; Izbicki, John A.; Reichard, Eric G.

1998-01-01

To better understand flow processes, solute-transport processes, and ground-water/surface-water interactions on the Santa Clara River in Ventura County, California, a 24-hour fluorescent-dye tracer study was performed under steady-state flow conditions on a 28-mile reach of the river. The study reach includes perennial (uppermost and lowermost) subreaches and ephemeral subreaches of the lower Piru Creek and the middle Santa Clara River. Dye was injected at a site on Piru Creek, and fluorescence of river water was measured continuously at four sites and intermittently at two sites. Discharge measurements were also made at the six sites. The time of travel of the dye, peak dye concentration, and time-variance of time-concentration curves were obtained at each site. The long tails of the time-concentration curves are indicative of sources/sinks within the river, such as riffles and pools, or transient bank storage. A statistical analysis of the data indicates that, in general, the transport characteristics follow Fickian theory. These data and previously collected discharge data were used to calibrate a one-dimensional flow model (DAFLOW) and a solute-transport model (BLTM). DAFLOW solves a simplified form of the diffusion-wave equation and uses empirical relations between flow rate and cross-sectional area, and flow rate and channel width. BLTM uses the velocity data from DAFLOW and solves the advection-dispersion transport equation, including first-order decay. The simulations of dye transport indicated that (1) ground-water recharge explains the loss of dye mass in the middle, ephemeral, subreaches, and (2) ground-water recharge does not explain the loss of dye mass in the uppermost and lowermost, perennial, subreaches. This loss of mass was simulated using a linear decay term. The loss of mass in the perennial subreaches may be caused by a combination of photodecay or adsorption/desorption.

Time of travel of the Flint River, Utah Dam to highway M-13, Michigan, August 4-8, 1981

USGS Publications Warehouse

Cummings, T. Ray; Miller, John B.

1982-01-01

Tracing of rhodamine WT dye has provided time-of-travel data for waste-load allocation studies of a 42.8-mile reach of the Flint River at low flow. A discharge equaled or exceeded about 90 percent of the time was measured at Grand Traverse Street in Flint before dye injection. Dye was injected at two locations in Flint--at Utah Dam and at Grand Traverse Street, From Utah Dam to Grand Traverse Street, the mean velocity of flow was about 0.1 foot per second; time-of-travel was 35.3 hours. From Grand Traverse Street to Highway M-13, mean velocity was about 0.7 foot per second; time-of-travel was 78.8 hours. Time-of-travel for the reach between Utah Dam and Highway M-13 was thus 114 hours.

Clinical utility of the additional use of blue dye for indocyanine green for sentinel node biopsy in breast cancer.

PubMed

Ji, Yinan; Luo, Ningbin; Jiang, Yi; Li, Qiuyun; Wei, Wei; Yang, Huawei; Liu, Jianlun

2017-07-01

Indocyanine green (ICG) is widely used as a tracer in sentinel lymph node biopsy (SLNB) of patients with breast cancer. Whether SLNB performance can be improved by supplementing ICG with methylene blue dye remains controversial. This study compared the performance of SLNB when ICG was used alone or with blue dye. Consecutive patients with T1-3 primary breast cancer at our hospital were recruited into our study and randomized to undergo SLNB with ICG alone (n = 62) or with the combination of ICG and blue dye (n = 65). We compared the two methods in terms of identification rate, number and detection time of sentinel lymph nodes (SLNs) removed. SLN identification rate were similar in the absence (95.2%) or presence of blue dye (98.5%, P = 0.578) but significantly, more average nodes were removed when blue dye was used (3.8 ± 1.5 versus 2.7 ± 1.2, P = 0.000), and the average time for detecting each SLN was significantly shorter (3.91 ± 1.87 versus 5.65 ± 2.95 min; P = 0.000). No patient in the study experienced severe adverse reactions or complications. Recurrence of axillary node was detected in one patient (1.6%) using ICG alone but not in any patients using ICG and blue dye. The efficiency and sensitivity of SLNB can be improved by combining ICG with blue dye. Copyright © 2017 Elsevier Inc. All rights reserved.

Why Congo red binding is specific for amyloid proteins - model studies and a computer analysis approach.

PubMed

Roterman, I; KrUl, M; Nowak, M; Konieczny, L; Rybarska, J; Stopa, B; Piekarska, B; Zemanek, G

2001-01-01

The complexing of Congo red in two different ligand forms - unimolecular and supramolecular (seven molecules in a micelle) - with eight deca-peptides organized in a b-sheet was tested by computational analysis to identify its dye-binding preferences. Polyphenylananine and polylysine peptides were selected to represent the specific side chain interactions expected to ensure particularly the stabilization of the dye-protein complex. Polyalanine was used to verify the participation of non-specific backbone-derived interactions. The initial complexes for calculation were constructed by intercalating the dye between the peptides in the middle of the beta-sheet. The long axis of the dye molecule (in the case of unimolecular systems) or the long axis of the ribbon-like micelle (in the case of the supramolecular dye form) was oriented parallel to the peptide backbone. This positioning maximally reduced the exposure of the hydrophobic diphenyl (central dye fragment) to water. In general the complexes of supramolecular Congo red ligands appeared more stable than those formed by individual dye molecules. Specific interactions (electrostatic and/or ring stacking) dominated as binding forces in the case of the single molecule, while non-specific surface adsorption seemed decisive in complexing with the supramolecular ligand. Both the unimolecular and supramolecular versions of the dye ligand were found to be likely to form complexes of sufficient stability with peptides. The low stability of the protein and the gap accessible to penetration in the peptide sheet seem sufficient for supramolecular ligand binding, but the presence of positively charged or hydrophobic amino acids may strengthen binding significantly. The need for specific interaction makes single-molecule Congo red binding rather unusual as a general amyloid protein ligand. The structural feature of Congo red, which enables specific and common interaction with amyloid proteins, probably derives from the ribbon-like self-assembled form of the dye.

Solar light induced and TiO2 assisted degradation of textile dye reactive blue 4.

PubMed

Neppolian, B; Choi, H C; Sakthivel, S; Arabindoo, B; Murugesan, V

2002-03-01

Aqueous solutions of reactive blue 4 textile dye are totally mineralised when irradiated with TiO2 photocatalyst. A solution containing 4 x 10(-4) M dye was completely degraded in 24 h irradiation time. The intensity of the solar light was measured using Lux meter. The results showed that the dye molecules were completely degraded to CO2, SO4(2-), NO3-, NH4+ and H2O under solar irradiation. The addition of hydrogen peroxide and potassium persulphate influenced the photodegradation efficiency. The rapidity of photodegradation of dye intermediates were observed in the presence of hydrogen peroxide than in its absence. The auxiliary chemicals such as sodium carbonate and sodium chloride substantially affected the photodegradation efficiency. High performance liquid chromatography and chemical oxygen demand were used to study the mineralisation and degradation of the dye respectively. It is concluded that solar light induced degradation of textile dye in wastewater is a viable technique for wastewater treatment.

Photochemically deposited nano-Ag/sol-gel TiO2-In2O3 mixed oxide mesoporous-assembled nanocrystals for photocatalytic dye degradation.

PubMed

Sreethawong, Thammanoon; Ngamsinlapasathian, Supachai; Yoshikawa, Susumu

2014-05-01

This work focused on the improvement of the photocatalytic activity for Congo Red (CR) azo dye degradation of mesoporous-assembled 0.95 TiO2-0.05 In2O3 mixed oxide photocatalyst (with a TiO2-to-In2O3 molar ratio of 0.95:0.05) by loading with Ag nanoparticles. The mesoporous-assembled 0.95TiO2-0.05In2O3 mixed oxide photocatalyst was synthesized by a hydrolytic sol-gel method with the aid of a structure-directing surfactant, prior to loading with various Ag contents (0.5-2 wt.%) by a photochemical deposition method. The optimum Ag loading content was found to be 1.5 wt.%, exhibiting a great increase in photocatalytic CR dye degradation activity. The 1.5 wt.% Ag-loaded 0.95TiO2-0.05In2O3 mixed oxide photocatalyst was further applied for the CR dye degradation in the presence of water hardness. Different types (Ca2+ and Ca2+ -Mg2+ mixture) and concentrations (200 and 500 mg/l) of water hardness were investigated. The results showed that the water hardness reduced the photocatalytic CR dye degradation activity, particularly for the extremely hard water with 500 mg/l of Ca2+ -Mg2+ mixture. The adjustment of initial solution pH of the CR dye-containing hard water to an appropriate value was found to improve the photocatalytic CR dye degradation activity under the identical reaction conditions. Copyright © 2014 Elsevier Inc. All rights reserved.

Band-engineering of TiO2 as a wide-band gap semiconductor using organic chromophore dyes

NASA Astrophysics Data System (ADS)

Wahyuningsih, S.; Kartini, I.; Ramelan, A. H.; Saputri, L. N. M. Z.; Munawaroh, H.

2017-07-01

Bond-engineering as applied to semiconductor materials refers to the manipulation of the energy bands in order to control charge transfer processes in a device. When the device in question is a photoelectrochemical cell, the charges affected by drift become the focus of the study. The ideal band gap of semiconductors for enhancement of photocatalyst activity can be lowered to match with visible light absorption and the location of conduction Band (CB) should be raised to meet the reducing capacity. Otherwise, by the addition of the chromofor organic dyes, the wide-band gab can be influences by interacation resulting between TiO2 surface and the dyes. We have done the impruvisation wide-band gap of TiO2 by the addition of organic chromophore dye, and the addition of transition metal dopand. The TiO2 morphology influence the light absorption as well as the surface modification. The organic chromophore dye was syntesized by formation complexes compound of Co(PAR)(SiPA)(PAR)= 4-(2-piridylazoresorcinol), SiPA = Silyl propil amine). The result showed that the chromophore groups adsorbed onto TiO2 surface can increase the visible light absorption of wide-band gab semiconductor. Initial absorption of a chromophore will affect light penetration into the material surfaces. The use of photonic material as a solar cell shows this phenomenon clearly from the IPCE (incident photon to current conversion efficiency) measurement data. Organic chromophore dyes of Co(PAR)(SiPA) exhibited the long wavelength absorption character compared to the N719 dye (from Dyesol).

Heterogeneous photo-Fenton decolorization of Orange II over Al-pillared Fe-smectite: response surface approach, degradation pathway, and toxicity evaluation.

PubMed

Li, Huiyuan; Li, Yanli; Xiang, Luojing; Huang, Qianqian; Qiu, Juanjuan; Zhang, Hui; Sivaiah, Matte Venkata; Baron, Fabien; Barrault, Joel; Petit, Sabine; Valange, Sabine

2015-04-28

A ferric smectite clay material was synthesized and further intercalated with Al2O3 pillars for the first time with the aim of evaluating its ability to be used as heterogeneous catalyst for the photo-Fenton decolorization of azo dye Orange II. UV irradiation was found to enhance the activity of the catalyst in the heterogeneous photo-Fenton process. Catalyst loading of 0.5g/L and hydrogen peroxide concentration of 13.5mM yielded a remarkable color removal, accompanied by excellent catalyst stability. The decolorization of Orange II followed the pseudo-first-order kinetics for initial dye concentrations from 20 to 160mg/L. The central composite design (CCD) based on the response surface methodology (RSM) was applied to evaluate the effects of several operating parameters, namely initial pH, catalyst loading and hydrogen peroxide concentration, on the decolorization efficiency. The RSM model was derived and the response surface plots were developed based on the results. Moreover, the main intermediate products were separated and identified using gas chromatography-mass spectrometry (GC-MS) and a possible degradation pathway was proposed accordingly. The acute toxicity experiments illustrated that the Daphniamagna immobilization rate continuously decreased during 150min reaction, indicating that the effluent was suitable for sequential biological treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

Removal of Crystal Violet by Using Reduced-Graphene-Oxide-Supported Bimetallic Fe/Ni Nanoparticles (rGO/Fe/Ni): Application of Artificial Intelligence Modeling for the Optimization Process.

PubMed

Ruan, Wenqian; Hu, Jiwei; Qi, Jimei; Hou, Yu; Cao, Rensheng; Wei, Xionghui

2018-05-22

Reduced-graphene-oxide-supported bimetallic Fe/Ni nanoparticles were synthesized in this study for the removal of crystal violet (CV) dye from aqueous solutions. This material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), Raman spectroscopy, N₂-sorption, and X-ray photoelectron spectroscopy (XPS). The influence of independent parameters (namely, initial dye concentration, initial pH, contact time, and temperature) on the removal efficiency were investigated via Box⁻Behnken design (BBD). Artificial intelligence (i.e., artificial neural network, genetic algorithm, and particle swarm optimization) was used to optimize and predict the optimum conditions and obtain the maximum removal efficiency. The zero point of charge (pH ZPC ) of rGO/Fe/Ni composites was determined by using the salt addition method. The experimental equilibrium data were fitted well to the Freundlich model for the evaluation of the actual behavior of CV adsorption, and the maximum adsorption capacity was estimated as 2000.00 mg/g. The kinetic study discloses that the adsorption processes can be satisfactorily described by the pseudo-second-order model. The values of Gibbs free energy change (Δ G ⁰), entropy change (Δ S ⁰), and enthalpy change (Δ H ⁰) demonstrate the spontaneous and endothermic nature of the adsorption of CV onto rGO/Fe/Ni composites.

Optimization of process variables for decolorization of Disperse Yellow 211 by Bacillus subtilis using Box-Behnken design.

PubMed

Sharma, Praveen; Singh, Lakhvinder; Dilbaghi, Neeraj

2009-05-30

Decolorization of textile azo dye Disperse Yellow 211 (DY 211) was carried out from simulated aqueous solution by bacterial strain Bacillus subtilis. Response surface methodology (RSM), involving Box-Behnken design matrix in three most important operating variables; temperature, pH and initial dye concentration was successfully employed for the study and optimization of decolorization process. The total 17 experiments were conducted in the study towards the construction of a quadratic model. According to analysis of variance (ANOVA) results, the proposed model can be used to navigate the design space. Under optimized conditions the bacterial strain was able to decolorize DY 211 up to 80%. Model indicated that initial dye concentration of 100 mgl(-1), pH 7 and a temperature of 32.5 degrees C were found optimum for maximum % decolorization. Very high regression coefficient between the variables and the response (R(2)=0.9930) indicated excellent evaluation of experimental data by polynomial regression model. The combination of the three variables predicted through RSM was confirmed through confirmatory experiments, hence the bacterial strain holds a great potential for the treatment of colored textile effluents.

Fabrication and investigation of MnFe2O4/MWCNTs nanocomposite by hydrothermal technique and adsorption of cationic and anionic dyes

NASA Astrophysics Data System (ADS)

Kafshgari, Leila Asadi; Ghorbani, Mohsen; Azizi, Asghar

2017-10-01

In present study, MnFe2O4/MWCNT nanocomposite synthesized using the hydrothermal technique and has been used for removal of DR16 and Y40 dyes from aqueous solutions. The characteristics results of FTIR, XRD, FESEM and TEM indicated that the nanoadsorbent was successfully fabricated. Magnetic sensitivity results demonstrated that the nanoparticles with saturation magnetization (Ms) value of 8.93 emu g-1 would have a fast magnetic response. The performance of adsorption was investigated in a batch reactor employing parameters expected to affect the maximum adsorption capacity (qm) such as pH, contact time, initial dye concentration and temperature. The highest sorption capacities of DR16 and Y40 after 300 min at 328 K were found to be 607.79 mg/g and 280 mg/g at pH of 2 and 6, respectively. The adsorption behavior over the time was assessed through pseudo-first, pseudo-second and Weber-Morris intra particle diffusion models. It was found that the pseudo-second order model gave the best agreement to the experimental data. Adsorbate-adsorbent interactions as a function of temperature was evaluated by Langmuir, Freundlich, Temkin and Sips isotherm models from which Sips isotherm had the highest consistency with the experimental data. Thermodynamic parameters including ΔG°, ΔS° and ΔH° were determined over the temperature range of 298-328 K. The results revealed that the adsorption reaction of DR16 onto MnFe2O4/MWCNT was spontaneous and exothermic, whilst the sorption process of Y40 was spontaneous and endothermic. In addition, activation energy values implied that the removal process of DR16 and Y40 was physical in nature.

Intracellular pH in Gastric and Rectal Tissue Post Cardiac Arrest

NASA Astrophysics Data System (ADS)

Fisher, Elaine M.; Steiner, Richard P.; LaManna, Joseph C.

We directly measured pHi using the pH sensitive dye, neutral red. We defined pHi for rectal and gastric tissue in whole tissue and by layer under control and arrest conditions. Fifteen minutes of arrest was not sufficient time to alter the pHi at the rectal or gastric site. On initial inspection, the stomach may be more sensitive to ischemic changes than the rectum. Understanding the mechanism by which PCO2 generation is used to track clinical changes is vital to the early detection of tissue dysoxia in order to effectively treat and manage critically ill patients.

Ultrasound assisted enhancement in natural dye extraction from beetroot for industrial applications and natural dyeing of leather.

PubMed

Sivakumar, Venkatasubramanian; Anna, J Lakshmi; Vijayeeswarri, J; Swaminathan, G

2009-08-01

There is a growing demand for eco-friendly/non-toxic colorants, specifically for health sensitive applications such as coloration of food and dyeing of child textile/leather garments. Recently, dyes derived from natural sources for these applications have emerged as an important alternative to potentially harmful synthetic dyes and pose need for suitable effective extraction methodologies. The present paper focus on the influence of process parameters for ultrasound assisted leaching of coloring matter from plant materials. In the present work, extraction of natural dye from beetroot using ultrasound has been studied and compared with static/magnetic stirring as a control process at 45 degrees C. The influence of process parameters on the extraction efficiency such as ultrasonic output power, time, pulse mode, effect of solvent system and amount of beetroot has been studied. The use of ultrasound is found to have significant improvement in the extraction efficiency of colorant obtained from beetroot. Based on the experiments it has been found that a mixture of 1:1 ethanol-water with 80W ultrasonic power for 3h contact time provided better yield and extraction efficiency. Pulse mode operation may be useful in reducing electrical energy consumption in the extraction process. The effect of the amount of beetroot used in relation to extraction efficiency has also been studied. Two-stage extraction has been studied and found to be beneficial for improving the yield for higher amounts of beetroot. Significant 8% enhancement in % yield of colorant has been achieved with ultrasound, 80W as compared to MS process both using 1:1 ethanol-water. The coloring ability of extracted beet dye has been tested on substrates such as leather and paper and found to be suitable for dyeing. Ultrasound is also found to be beneficial in natural dyeing of leather with improved rate of exhaustion. Both the dyed substrates have better color values for ultrasonic beet extract as inferred from reflectance measurement. Therefore, the present study clearly offers efficient extraction methodology from natural dye resources such as beetroot with ultrasound even dispensing with external heating. Thereby, also making eco-friendly non-toxic dyeing of fibrous substances a potential viable option.

Effect of auxiliary group for p-type organic dyes in NiO-based dye-sensitized solar cells: The first principal study

NASA Astrophysics Data System (ADS)

Li, Juan; Zhang, Shijie; Shao, Di; Yang, Zhenqing; Zhang, Wansong

2018-03-01

Auxiliary acceptor groups play a crucial role in D-A-π-A structured organic dyes. In this paper, we designed three D-A-π-A structured organic molecules based on the prototype dye QT-1, named ME18-ME20, and further investigated their electronic and optical properties with density functional theory (DFT) and time-dependent DFT (TDDFT). The calculated results indicate that the scope and intensity of dyes' absorption spectra have some outstanding changes by inserting auxiliary groups. ME20 has not only 152 nm redshifts to long wave orientation, but also 78% increased oscillator strength compared to QT-1, and its absorption spectrum broadens region even up to 1400 nm. Then, we studied the reason that the effect of the introduced different auxiliary acceptor groups in these dyes through their ground states geometries and energy levels, electron transfer and recombination rate.

Fe-tannic acid complex dye as photo sensitizer for different morphological ZnO based DSSCs

NASA Astrophysics Data System (ADS)

Çakar, Soner; Özacar, Mahmut

2016-06-01

In this paper we have synthesized different morphological ZnO nanostructures via microwave hydrothermal methods at low temperature within a short time. We described different morphologies of ZnO at different Zn(NO3)2/KOH mole ratio. The ZnO nanostructures were characterized via X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and UV-vis spectrophotometry. All ZnO structures have hexagonal wurtzite type structures. The FESEM images showed various morphologies of ZnO such as plate, rod and nanoparticles. Dye sensitized solar cells have been assembled by these different morphological structures photo electrode and tannic acid or Fe-tannic acid complex dye as sensitizer. We have achieved at maximum efficiencies of photovoltaic cells prepared with ZnO plate in all dye systems. The conversion efficiencies of dye sensitized solar cells are 0.37% and 1.00% with tannic acid and Fe-tannic acid complex dye, respectively.

Color removal from acid and reactive dye solutions by electrocoagulation and electrocoagulation/adsorption processes.

PubMed

Bellebia, S; Kacha, S; Bouberka, Z; Bouyakoub, A Z; Derriche, Z

2009-04-01

In this study, electrocoagulation of Marine Blue Erionyl MR (acid dye) and electrocoagulation followed by adsorption of Brilliant Blue Levafix E-BRA (reactive dye) from aqueous solutions were investigated, using aluminum electrodes and granular activated carbon (GAC). In the electrocoagulation and adsorption of dyestuff solutions, the effects of current density, loading charge, pH, conductivity, stirring velocity, contact time, and GAC concentration were examined. The optimum conditions for the electrocoagulation process were identified as loading charges 7.46 and 1.49 F/m3, for a maximum abatement of 200 mg/L reactive and acid dye, respectively. The residual reactive dye concentration was completely removed with 700 mg/L GAC. The results of this investigation provide important data for the development of a combined process to remove significant concentrations of recalcitrant dyes from water, using moderate activated carbon energy and aluminum consumption, and thereby lowering the cost of treatment.

Characterization of N3 dye adsorption on TiO2 using quartz-crystal microbalance with dissipation monitoring

NASA Astrophysics Data System (ADS)

Wayment-Steele, Hannah K.; Johnson, Lewis E.; Dixon, Matthew C.; Johal, Malkiat S.

2013-09-01

Understanding the kinetics of dye adsorption on semiconductors is crucial for designing dye-sensitized solar cells (DSSCs) with enhanced efficiency. Harms et al. recently applied the Quartz-Crystal Microbalance with Dissipation Monitoring (QCM-D) to study in situ dye adsorption on flat TiO2 surfaces. QCM-D measures adsorption in real time and therefore allows one to determine the kinetics of the process. In this work, we characterize the adsorption of N3, a commercial RuBipy dye, using the native oxide layer of a titanium sensor to simulate the TiO2 substrate of a DSSC. We report equilibrium constants that are in agreement with previous absorbance studies of N3 adsorption, and therefore demonstrate the native oxide layer of a titanium sensor as a valid and readily available planar TiO2 morphology to study dye adsorption.

Eco-dyeing with biocolourant based on natural compounds

PubMed Central

Gong, Jixian; Ren, Yanfei; Zhang, Jianfei

2018-01-01

Biomass pigments have been regarded as promising alternatives to conventional synthetic dyestuffs for the development of sustainable and clean dyeing. This investigation focused on in situ dyeing of fabrics with biopigments derived from tea polyphenols via non-enzymatic browning reaction. The average particle size of dyed residual liquor with natural tea polyphenol was 717.0 nm (ranging from 615.5 to 811.2 nm), and the Integ value of dyed wool fabrics was the greatest compared to those of counterparts. In addition, the Integ values of dyed fabrics with residual liquor were much bigger than those with the first reaction solutions when dyed by identical dyeing liquor. As a result, the dyeing process could be carried out many times because the concentration of the residual liquor was relatively superior. All dyed fabrics acquired admirable rubbing as well as washing fastness, and the relevant dyeing mechanism has been analysed in the paper. PMID:29410827

PVA with nopal dye as holographic recording material

NASA Astrophysics Data System (ADS)

Toxqui-López, S.; Olivares-Pérez, A.; Fuentes-Tapia, I.; Pinto-Iguanero, B.

2011-09-01

Cactus nopal dye is introduced into a polyvinyl alcohol matrix achieving a like brown appearance thick film, such that they can be used as a recording medium. This dye material provides excellent property as photosensitizer, i.e., easy handling, low cost and can be used in real time holographic recording applications. The experimental results show the diffraction efficiencies obtained by recording grating patterns induced by a He-Cd laser (442nm). For the samples, a thick film of polyvinyl alcohol and dye from cactus nopal was deposited by the gravity technique on a glass substrate. This mixture dries to form a photosensitive emulsion.

Electroluminescent Properties in Organic Light-Emitting Diode Doped with Two Guest Dyes

NASA Astrophysics Data System (ADS)

Mori, Tatsuo; Kim, Hyeong-Gweon; Mizutani, Teruyoshi; Lee, Duck-Chool

2001-09-01

An organic light-emitting diode (OLED) with a squarylium dye-doped aluminium quinoline (Alq3) emission layer prepared by vapor deposition method has a pure red emission. However, since its luminance and electroluminescence (EL) efficiency is poor, the authors attended to improve the EL efficiency by doping a photosensitizer dye (a styryl dye, DCM) in an emission layer. The EL efficiency and luminance of DCM- and Sq-doped OLEDs are 2-3 times higher than those of only Sq-doped OLEDs. It was found that the excited energy is transferred from Alq3 to Sq through DCM.

Use of dye tracing to determine ground-water movement to Mammoth Crystal Springs, Sylvan Pass area, Yellowstone National Park, Wyoming

USGS Publications Warehouse

Spangler, Lawrence E.; Susong, David D.

2006-01-01

At the request of and in cooperation with the Geology Program at Yellowstone National Park, the U.S. Geological Survey conducted a hydrologic investigation of the Sylvan Pass area in June 2005 to determine the relation between surface water and ground-water flow to Mammoth Crystal Springs. Results of a dye-tracing investigation indicate that streamflow lost into talus deposits on Sylvan Pass enters the ground-water system and moves to the southeast to discharge at Mammoth Crystal Springs. Ground-water travel times to the springs from a distance of 1.45 miles and a vertical relief of 500 feet were less than 1 day, indicating apparent rates of movement of at least 8,000 feet per day, values that are similar to those in karst aquifers. Peak dye concentrations were reached about 2 days after dye injection, and transit time of most of the dye mass through the system was about 3 weeks. High permeability and rapid travel times within this aquifer also are indicated by the large variation in springflow in response to snowmelt runoff and precipitation, and by the high concentration of suspended sediment (turbidity) in the water discharging into the spring-fed lake.

Evaluation of Impermeant, DNA-Binding Dye Fluorescence as a Real-Time Readout of Eukaryotic Cell Toxicity in a High Throughput Screening Format

PubMed Central

Chiaraviglio, Lucius

2014-01-01

Abstract Interpretation of high throughput screening (HTS) data in cell-based assays may be confounded by cytotoxic properties of screening compounds. Therefore, assessing cell toxicity in real time during the HTS process itself would be highly advantageous. Here, we investigate the potential of putatively impermeant, fluorescent, DNA-binding dyes to give cell toxicity readout during HTS. Amongst 19 DNA-binding dyes examined, three classes were identified that were (1) permeant, (2) cytotoxic, or (3) neither permeant nor cytotoxic during 3-day incubation with a macrophage cell line. In the last class, four dyes (SYTOX Green, CellTox Green, GelGreen, and EvaGreen) gave highly robust cytotoxicity data in 384-well screening plates. As proof of principle, successful combination with a luminescence-based assay in HTS format was demonstrated. Here, both intracellular growth of Legionella pneumophila (luminescence) and host cell viability (SYTOX Green exclusion) were assayed in the same screening well. Incorporation of membrane-impermeant, DNA-binding, fluorescent dyes in HTS assays should prove useful by allowing evaluation of cytotoxicity in real time, eliminating reagent addition steps and effort associated with endpoint cell viability analysis, and reducing the need for follow-up cytotoxicity screening. PMID:24831788

DYNAMICS OF ACRIDINE ORANGE-CELL INTERACTION

PubMed Central

Robbins, Elliott; Marcus, Philip I.

1963-01-01

The in vitro localization of acridine orange (AO) in living cells was monitored by means of fluorescence microscopy, quantitative cell viability studies, and photofluorimetric measurements following dye-cell interaction. The parameters, pH, time, dye concentration, and the metabolic state of the cell were found to exert a profound influence on the time course and distribution of staining. The parameters studied are mutually interdependent, and intracellular dye localization may be predictably altered by their appropriate manipulation. Conditions are defined whereby two morphologically distinct but physiologically interrelated reactions, namely, acridine orange particle (AOP) formation and cytoplasmic reddening (CR) may be caused, prevented, reversed, or modified. These results are explained in terms of the facilitation or inhibition of an intracytoplasmic dye-segregating mechanism, in turn affected by the rate of dye ingress and the physiological state of the cell. Whereas the accumulation of AO in AOP is compatible with cell viability, the appearance of CR is correlated with cell death. It is pointed out that meaningful interpretation of vital staining requires precise regulation of many parameters in the extracellular milieu. A scheme of cell compartmentalization with respect to AO is proposed to satisfactorily account for the effects of environmental variations on the distribution and ultimate fate of intracellular dye. The AOP are viewed as normally present acid phosphatase-positive multivesicular bodies. PMID:14079487

Dyeing regions of oxidative hair dyes in human hair investigated by nanoscale secondary ion mass spectrometry.

PubMed

Kojima, Toru; Yamada, Hiromi; Yamamoto, Toshihiko; Matsushita, Yasuyuki; Fukushima, Kazuhiko

2013-06-01

To develop more effective oxidative hair coloring products, it is important to understand the localization of colored chromophores, which are formed from oxidative dyes, in the fine structure of hair. However, the dyeing regions of oxidative hair dyes in the fine structure of hair have not been extensively examined. In this study, we investigated the distribution and localization of colored chromophores formed by an oxidative hair coloring product in the fine structure of human hair by using a stable isotope-labeled oxidative dye with nanoscale secondary ion mass spectrometry (NanoSIMS). First, formation of the colored chromophore from a deuterium-labeled oxidative dye was examined by visible spectra similarly to a study of its formation using nonlabeled oxidative dye. Furthermore, the formation of binuclear indo dye containing deuterium in its chemical structure was confirmed using time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis. As a result of the NanoSIMS image on a cross-sectional dyed hair, although deuterium ions were detected in whole hair cross-section, quite a few of them were detected at particulate regions. These particulate regions of the dyed black hair in which deuterium ions were intensely detected were identified as melanin granules, by comparing the dyeing behaviors of black and white hair. NanoSIMS analysis revealed that melanin granules of black human hair are important dyeing regions in oxidative hair coloring. Copyright © 2013 Elsevier B.V. All rights reserved.

Inclusion of aggregation effect to evaluate the performance of organic dyes in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Sun, Kenan; Zhang, Weiyi; Heng, Panpan; Wang, Li; Zhang, Jinglai

2018-05-01

Two new indoline-based D-A-π-A dyes, D3F and D3F2 (see Scheme 1), are developed on the basis of the reported D3 by insertion of one or two F atoms on benzothiadiazole group. Our central aim is to explore high-efficiency organic dyes applied in dye-sensitized solar cells by inclusion of a simple group rather than by employment of new complicated groups. The performance of two new designed organic dyes, D3F and D3F2, is compared with that of D3 from various aspects including absorption spectrum, light harvesting efficiency, driving force, and open-circuit voltage. Besides the isolated dye, the interfacial property between dye and TiO2 surface is studied. D3F and D3F2 do not show absolute superiority than D3 not only for the isolated dyes but also for the monomeric adsorption system. However, D3F and D3F2 would effectively reduce the influence of aggregation resulting in the much smaller intermolecular electronic coupling. Although the aggregation has attracted much attention recently, it is studied alone in most of studies. To comprehensively evaluate the performance of dye-sensitized solar cells, it is necessary to consider aggregation along with electron injection time from dye into TiO2 rather than only static items, such as, band gap and absorption region.

[Optimization of labeling and localizing bacterial membrane and nucleus with FM4-64 and Hoechst dyes].

PubMed

Wang, Jing; Han, Yanping; Yang, Ruifu; Zhao, Xingxu

2015-08-04

To observe cell membrane and nucleus in bacteria for subcellular localization. FM4-64 and Hoechst were dyed that can label cell membrane and nucleus, respectively. Both dyes were used to co-stain the membranes and nucleus of eight bacterial strains ( Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Yersinia pestis, Legionella pneumonia, Vibrio cholerae and Bacillus anthracis). E. coli was dyed with different dye concentrations and times and then observed by confocal fluorescence microscopic imaging. Fluorescence intensity of cell membrane and nucleus is affected by dye concentrations and times. The optimal conditions were determined as follows: staining cell membrane with 20 μg/mL FM4-64 for 1 min and cell nucleus with 20 μg/mL Hoechst for 20 min. Gram-negative bacteria were dyed better than gram-positive bacteria with FM4-64dye. FM4-64 and Hoechst can be used to stain membrane and nucleus in different types of bacteria. Co-staining bacterial membrane and nucleus provides the reference to observe cell structure in prokaryotes for studying subcellular localization.

Growth and physiology of Clostridium perfringens wild-type and ΔazoC knockout: an azo dye exposure study.

PubMed

Morrison, Jessica M; John, Gilbert H

2016-02-01

Clostridium perfringens, a strictly anaerobic micro-organism and inhabitant of the human intestine, has been shown to produce the azoreductase enzyme AzoC, an NAD(P)H-dependent flavin oxidoreductase. This enzyme reduces azo dyes to aromatic amines, which are carcinogenic in nature. A significant amount of work has been completed that focuses on the activity of this enzyme; however, few studies have been completed that focus on the physiology of azo dye reduction. Dye reduction studies coupled with C. perfringens growth studies in the presence of ten different azo dyes and in media of varying complexities were completed to compare the growth rates and dye-reducing activity of C. perfringens WT cells, a C. perfringens ΔazoC knockout, and Bifidobacterium infantis, a non-azoreductase-producing control bacterium. The presence of azo dyes significantly increased the generation time of C. perfringens in rich medium, an effect that was not seen in minimal medium. In addition, azo dye reduction studies with the ΔazoC knockout suggested the presence of additional functional azoreductases in this medically important bacterium. Overall, this study addresses a major gap in the literature by providing the first look, to our knowledge, at the complex physiology of C. perfringens upon azo dye exposure and the effect that both azo dyes and the azoreductase enzyme have on growth.

Decolorization of the azo dye Acid Orange 51 by laccase produced in solid culture of a newly isolated Trametes trogii strain.

PubMed

Daâssi, Dalel; Zouari-Mechichi, Hela; Frikha, Fakher; Martinez, Maria Jesus; Nasri, Moncef; Mechichi, Tahar

2013-04-01

This study concerns the decolorization and detoxification of the azo dye Acid Orange 51 (AO51) by crude laccase from Trametes trogii produced in solid culture using sawdust as support media. A three-level Box-Behnken factorial design with four factors (enzyme concentration, 1-hydroxybenzotriazole (HBT) concentration, dye concentration and reaction time) combined with response surface methodology was applied to optimize AO51 decolorization. A mathematical model was developed showing the effect of each factor and their interactions on color removal. The model predicted that Acid Orange 51 decolorization above 87.87 ± 1.27 % could be obtained when enzyme concentration, HBT concentration, dye concentration and reaction time were set at 1 U/mL, 0.75 mM, 60 mg/L and 2 days, respectively. The experimental values were in good agreement with the predicted ones and the models were highly significant, the correlation coefficient (R 2 ) being 0.9. Then the desirability function was employed to determine the optimal decolorization condition for each dye and minimize the process cost simultaneously. In addition, germination index assay showed that laccase-treated dye was detoxified; however in the presence of HBT, the phytotoxicity of the treated dye was increased. By using cheap agro-industrial wastes, such as sawdust, a potential laccase was obtained. The low cost of laccase production may further broaden its application in textile wastewater treatment.

Enhanced dewaterability of textile dyeing sludge using micro-electrolysis pretreatment.

PubMed

Ning, Xun-An; Wen, Weibin; Zhang, Yaping; Li, Ruijing; Sun, Jian; Wang, Yujie; Yang, Zuoyi; Liu, Jingyong

2015-09-15

The effects of micro-electrolysis treatment on textile dyeing sludge dewatering and its mechanisms were investigated in this study. Capillary suction time (CST) and settling velocity (SV) were used to evaluate sludge dewaterability. Extracellular polymeric substances (EPS) concentration and sludge disintegration degree (DDSCOD) were determined to explain the observed changes in sludge dewaterability. The results demonstrated that the micro-electrolysis could significantly improve sludge dewaterability by disrupting the sludge floc structure. The optimal conditions of sludge dewatering were the reaction time of 20 min, initial pH of 2.5, Fe/C mass ratio of 1/1, and the iron powder dosage of 2.50 g/L, which achieved good CST (from 34.1 to 27.8 s) and SV (from 75 to 60%) reduction efficiency. In addition, the scanning electron microscope (SEM) images revealed that the treated sludge floc clusters are broken up and that the dispersion degree is better than that of a raw sludge sample. The optimal EPS concentration and DDSCOD to obtain maximum sludge dewaterability was 43-46 mg/L and 4.2-4.9%, respectively. The destruction of EPS was one of the primary reasons for the improvement of sludge dewaterability during micro-electrolysis treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

On the influence of DC electric fields on the aerosol assisted chemical vapor deposition growth of photoactive titanium dioxide thin films.

PubMed

Romero, Luz; Binions, Russell

2013-11-05

Titanium dioxide thin films were deposited on fluorine doped tin oxide glass substrate from the electric field assisted aerosol chemical vapor deposition (EACVD) reaction of titanium isopropoxide (TTIP, Ti(OC3H7)4) in toluene on glass substrates at a temperature of 450 °C. DC electric fields were generated by applying a potential difference between the electrodes of the transparent coated oxide coated glass substrates during the deposition. The deposited films were characterized using scanning electron microscopy, X-ray diffraction, atomic force microscopy, Raman spectroscopy, and UV-vis spectroscopy. The photoactivity and hydrophilicity of the deposited films were also analyzed using a dye-ink test and water-contact angle measurements. The characterization work revealed that the incorporation of DC electric fields produced significant reproducible changes in the film microstructure, preferred crystallographic orientation, roughness, and film thickness. Photocatalytic activity was calculated from the half-time (t1/2) or time taken to degrade 50% of the initial resazurin dye concentration. A large improvement in photocatalytic activity was observed for films deposited using an electric field with a strong orientation in the (004) direction (t1/2 17 min) as compared to a film deposited with no electric field (t1/2 40 min).

Allergic contact dermatitis associated with reactive dyes in a dark garment: a case report.

PubMed

Moreau, Linda; Goossens, An

2005-09-01

In this study, we present a case of a patient who has not been occupationally exposed to reactive dyes, but did present with a dermatitis from wearing a dark cotton garment. The patient experienced reactivation of his dermatitis when rewearing a new unwashed dark T-shirt made of 100% cotton (in fact, the patient reported that it had to be washed at least 3 times before the skin reaction disappeared). He presented positive patch tests to 6 reactive dyes from Chemotechnique textile series. The clothing could not be proved as the true cause of the dermatitis, but resolution occurred upon removal of the suspected garment. This suggests that contact allergy to the reactive dyes (he did not react to any other dyes and his garment was a natural fabric) was likely responsible. With this report, we would like to emphasize that reactive dyes, as a class, should be considered as potential allergens, both occupationally and from non-occupational exposure such as garments. If garments containing reactive dyes are not properly rinsed in the manufacturing process, we believe that excess of dye can be retained that may cause allergic contact dermatitis (ACD). As the reactive dyes and their hydrolysis products are very water-soluble, they can be easily washed off to prevent ACD.

Metal-free organic dyes for TiO2 and ZnO dye-sensitized solar cells

PubMed Central

Selopal, Gurpreet Singh; Wu, Hui-Ping; Lu, Jianfeng; Chang, Yu-Cheng; Wang, Mingkui; Vomiero, Alberto; Concina, Isabella; Diau, Eric Wei-Guang

2016-01-01

We report the synthesis and characterization of new metal-free organic dyes (namely B18, BTD-R, and CPTD-R) which designed with D-π-A concept to extending the light absorption region by strong conjugation group of π-linker part and applied as light harvester in dye sensitized solar cells (DSSCs). We compared the photovoltaic performance of these dyes in two different photoanodes: a standard TiO2 mesoporous photoanode and a ZnO photoanode composed of hierarchically assembled nanostructures. The results demonstrated that B18 dye has better photovoltaic properties compared to other two dyes (BTD-R and CPTD-R) and each dye has higher current density (Jsc) when applied to hierarchical ZnO nanocrystallites than the standard TiO2 mesoporous film. Transient photocurrent and photovoltage decay measurements (TCD/TVD) were applied to systematically study the charge transport and recombination kinetics in these devices, showing the electron life time (τR) of B18 dye in ZnO and TiO2 based DSSCs is higher than CPTD-R and BTD-R based DSSCs, which is consistent with the photovoltaic performances. The conversion efficiency in ZnO based DSSCs can be further boosted by 35%, when a compact ZnO blocking layer (BL) is applied to inhibit electron back reaction. PMID:26738698

Can nitro groups really anchor onto TiO 2? Case study of dye-to-TiO 2 adsorption using azo dyes with NO 2 substituents

DOE PAGES

Zhang, Lei; Cole, Jacqueline M.

2016-06-21

The nitro group has recently been suggested as a new type of anchor for dye-sensitized solar cells (DSSCs) and has shown promising optoelectronic properties. Considering the excellent electron withdrawing ability of the nitro group and wider materials selection brought about by this substituent, it is helpful to evaluate the interfacial structures and photophysics of more organic dyes where NO 2 poses as the dye-to-TiO 2 anchor. A computational study on a family of azo dyes bearing a nitro group is presented in this paper, where the effect of certain side groups on their optical properties is examined. Both isolated dyemore » molecules and dye/TiO 2 nanocomposites are studied via density functional theory and time-dependent density functional theory, with complementary experimental UV/vis absorption spectroscopy and photovoltaic device testing. Results demonstrate that these nitro-containing dyes prefer a monodentate anchoring mode on a TiO 2 cluster. These nitro dyes reveal weak, but non-negligible, adsorption onto TiO 2; yet, very low photovoltaic performance once incorporated into a DSSC device. Finally, this poor delivery of nitro groups as DSSC anchors is ostensibly inconsistent with previous findings; but is rationalized via the “auxiliary anchor” concept.« less

Kinetics of proton uptake and dye binding by photoactive yellow protein in wild type and in the E46Q and E46A mutants.

PubMed

Borucki, Berthold; Devanathan, Savitha; Otto, Harald; Cusanovich, Michael A; Tollin, Gordon; Heyn, Maarten P

2002-08-06

We studied the kinetics of proton uptake and release by photoactive yellow protein (PYP) from Ectothiorhodospira halophila in wild type and the E46Q and E46A mutants by transient absorption spectroscopy with the pH-indicator dyes bromocresol purple or cresol red in unbuffered solution. In parallel, we investigated the kinetics of chromophore protonation as monitored by the rise and decay of the blue-shifted state I(2) (lambda(max) = 355 nm). For wild type the proton uptake kinetics is synchronized with the fast phase of I(2) formation (tau = 500 micros at pH 6.2). The transient absorption signal from the dye also contains a slower component which is not due to dye deprotonation but is caused by dye binding to a hydrophobic patch that is transiently exposed in the structurally changed and partially unfolded I(2) intermediate. This conclusion is based on the wavelength, pH, and concentration dependence of the dye signal and on dye measurements in the presence of buffer. SVD analysis, moreover, indicates the presence of two components in the dye signal: protonation and dye binding. The dye binding has a rise time of about 4 ms and is coupled kinetically with a transition between two I(2) intermediates. In the mutant E46Q, which lacks the putative internal proton donor E46, the formation of I(2) is accelerated, but the proton uptake kinetics remains kinetically coupled to the fast phase of I(2) formation (tau = 100 micros at pH 6.3). For this mutant the protein conformational change, as monitored by the dye binding, occurs with about the same time constant as in wild type but with reduced amplitude. In the alkaline form of the mutant E46A the formation of the I(2)-like intermediate is even faster as is the proton uptake (tau = 20 micros at pH 8.3). No dye binding occurred in E46A, suggesting the absence of a conformational change. In all of the systems proton release is synchronized with the decay of I(2). Our results support mechanisms in which the chromophore of PYP is protonated directly from the external medium rather than by the internal donor E46.

Histochemical study of trans-polyisoprene accumulation by spectral confocal laser scanning microscopy and a specific dye showing fluorescence solvatochromism in the rubber-producing plant, Eucommia ulmoides Oliver.

PubMed

Nakazawa, Yoshihisa; Takeda, Tsuyoshi; Suzuki, Nobuaki; Hayashi, Tatsushi; Harada, Yoko; Bamba, Takeshi; Kobayashi, Akio

2013-09-01

A microscopic technique combining spectral confocal laser scanning microscopy with a lipophilic fluorescent dye, Nile red, which can emit trans-polyisoprene specific fluorescence, was developed, and unmixed images of synthesized trans-polyisoprene in situ in Eucommia ulmoides were successfully obtained. The images showed that trans-polyisoprene was initially synthesized as granules in non-articulated laticifers that changed shape to fibers during laticifer maturation. Non-articulated laticifers are developed from single laticiferous cells, which are differentiated from surrounding parenchyma cells in the cambium. Therefore, these observations suggested that trans-polyisoprene biosynthesis first started in laticifer cells as granules and then the granules accumulated and fused in the inner space of the laticifers over time. Finally, laticifers were filled with the synthesized trans-polyisoprene, which formed a fibrous structure fitting the laticifers shape. Both trans- and cis-polyisoprene are among the most important polymers naturally produced by plants, and this microscopic technique combined with histological study should provide useful information in the fields of plant histology, bioindustry and phytochemistry.

Mesoporous activated carbon prepared from NaOH activation of rattan (Lacosperma secundiflorum) hydrochar for methylene blue removal.

PubMed

Islam, Md Azharul; Ahmed, M J; Khanday, W A; Asif, M; Hameed, B H

2017-04-01

Hydrothermal carbonization of biomass wastes presents a promising step in the production of cost-effective activated carbon. In the present work, mesoporous activated carbon (HAC) was prepared by the hydrothermal carbonization of rattan furniture wastes followed by NaOH activation. The textural and morphological characteristics, along with adsorption performance of prepared HAC toward methylene blue (MB) dye, were evaluated. The effects of common adsorption variables on performance resulted in a removal efficiency of 96% for the MB sample at initial concentration of 25mg/L, solution pH of 7, 30°C, and 8h. The Langmuir equation showed the best isotherm data correlation, with a maximum uptake of 359mg/g. The adsorbed amount versus time data was well fitted by a pseudo-second order kinetic model. The prepared HAC with a high surface area of 1135m 2 /g and an average pore size distribution of 35.5Å could be an efficient adsorbent for treatment of synthetic dyes in wastewaters. Copyright © 2017 Elsevier Inc. All rights reserved.

Catalytic Properties of Fe-containing Layered Aluminosilicates in Photo-oxidation of Dye “Methyl Green”

NASA Astrophysics Data System (ADS)

Shadrina, O. A.; Dashinamzhilova, E. Ts; Khankhasaeva, S. Ts

2017-11-01

The iron-containing materials with an iron content of 40 mg/g and 52.5 mg/g, a specific surface area of 107 m2/g and 96 m2/g are developed on the basis of natural layered aluminosilicate (montmorillonite) and polyhydroxo complexes of iron. It is shown that the materials exhibit high catalytic activity in the photo-oxidation of dye “Methyl Green”. The influence of physicochemical parameters (loading of the catalyst, a ratio of initial concentrations [H2O2]/[MG] on the efficiency of the dye photo-oxidation was established. The optimum conditions, which made it possible to achieve high mineralization and 100 % the dye oxidation efficiency were determined: the catalyst loading equal to 1.0 g/l and the ratio of [H2O2] and [MG] equal to stoichiometric ratio (55 mol/mol). The decrease of the total organic carbon content after photo-oxidation reaction was 56.5%. The average value of the quantum yield of the dye photo-oxidation was to 0.30 mol/Einstein. The results of the conducted research show that the developed iron-containing materials are the promising catalysts for photo-Fenton processes of oxidative degradation of organic compounds. The materials are of interest for use in wastewater treatment processes from toxic organic pollutants.