Use of some organic dyes in gamma irradiation dose determination

In the present work, the radiation-induced color bleaching of Remazol brilliant blue (RBB), Wegocet orange (WO), Methyl green (Me G) and Thioflavine S (Th S) dyes solutions was studied. Solutions of these dyes in different solvents were found to obey Beer’s law within certain concentration levels. The % color bleaching occurring in different dye solutions on using different gamma irradiation doses was determined and the data obtained showed the existence of good linear relationships among them in the four dye systems used. The linear sections lines were used as calibration curves for evaluating unknown gamma irradiation doses. From the obtained results, it was concluded that RBB in water, WO in ethanol, Me G in butanol and Th S in 60% ethanol–water mixture could be used for dose evaluation within the dose ranges 5–25 kGy for RBB, 20–90 kGy for WO, 10–70 kGy for Me G and 5–160 kGy for Th S. The sensitivity of the systems towards gamma radiations has been also reported.     

Experimental and modeling approach to decolorization of azo dyes by ultrasound: degradation of the hydrazone tautomer

Sonochemical bleaching of monoazo dyes C.I. Acid Orange 7 and C.I Acid Orange 8, which exist in their hydrazone forms in dye solutions, was investigated by irradiating 40 microM dye solutions using a 300 kHz emitter. It was found that the rate of bleaching was first-order with respect to the maximum absorption of the dye in the visible band and accelerated with increased acidity. Decolorization of Acid Orange 7 was slightly faster than that of Acid Orange 8 at equivalent test conditions. The oxidative degradation of Acid Orange 7 and Acid Orange 8 were modeled by means of density functional theory calculations. The adduct formation by hydroxyl radical attack to the carbon atom bearing the azo linkage was more preferred over the attack on the nitrogen atom. A competing reaction of hydrogen abstraction from the CH3 group in C.I Acid Orange 8 was found responsible for the difference in color removal rates.     

Polyvinyl butyral films containing leuco-malachite green as low-dose dosimeters

Thin films containing leuco-malachite green (LMG) dye in polyvinyl butyral (PVB) have been developed for dose measurements of a few hundreds Gy level. The film shows significant color change in the visible range, and the sensitivity of the film to absorbed dose was enhanced by addition of chloride-containing compounds, such as chloral hydrate or 2,2,2-trichloroethanol. The film is suitable as dosimeters for dose measurements, e.g. in food irradiation and environmental protection.     

Treatment of direct blending dye wastewater and recycling of dye sludge

A new sorbent material, barium sulfate-Direct Blending Yellow D-3RNL hybrid (BSD), was synthesized and characterized by various methods. Both the anionic dyes, Reactive Brilliant Red X-3B and Weak Acid Green GS were hardly adsorbed by the BSD material, while the sorption of Ethyl Violet (EV) and Victoria Blue B were extremely obvious. The sorption of cationic dyes obeyed the Langmuir isotherm model, which depended on the electric charge attraction. The saturation amount of EV adsorbed onto the BSD material approached to 39.36 mg/g. The sorption of EV changed little with pH from 3 to 12 while it increased with increasing levels of electrolyte. A dye wastewater sampled from Jinjiang Chemicals was treated, and the color removal rate was more than the COD removal rate. In addition, the cationic dye-BSD sludge was utilized as a colorant fill-in coating. The light stability and thermal stability of the colorant was measured and exhibited good features. This work provided a simple and eco-friendly method for dye wastewater treatment with recycling of waste.     

Electrochemical and Electrochromic Properties of Polymer Complex Films Composed of Polytetramethyleneviologen and Poly-[p-Styrenesulfonic Acid] Containing a Conductive Powder

The electrochemical and electrochromic properties of polymer films containing a conductive powder (SnO₂/TiO₂) have been investigated. The films are complexes of polytetramethyleneviologen and poly(p-styrenesulfonic acid). It was found that the coloration (purple) and bleaching rates of the composite films increase markedly with increasing conductive powder content(x). The coloring and bleaching of the composite film with x = 95 wt% were about 7 and 44 times faster, respectively, than those for an equivalent film without conductive powder. This increase in the rate of color change by introduction of a conductive powder was found to be correlated with the apparent diffusion coefficient (D _app) for the diffusionlike charge-transport process within the composite films which increases with increasing x. The D _app for the reduction process of the film with x = 95 wt% was larger by about 3 orders of magnitude than that for the unfilled film.     

An Optical Relative Humidity Sensing System

The relative humidity (RH) of air is an important parameter that needs to be measured in many industries. Brook et al.^[1,2] studied the response of Nafion films containing Crystal Violet to the relative humidity; Raimundo et al.^[3] investigated the composition of Nafion-Crystal Violet films and their casting processes. In this paper, the sensing film was prepared by entrapped Crystal Violet in the commercial Nafion film. The dry air was commercially available and the 100% RH air was obtained by bubbling dry air into a series of bubbling flasks filled with deionized water. A spectrophotometer was employed to monitor the absorption changes of the film at the range of 400nm to 700 nm.     

Dyed polyvinyl chloride films for use as high-dose routine dosimeters in radiation processing

Characteristics of the polyvinyl chloride (PVC) films containing 0.11 wt% of malachite green oxalate or 6GX-setoglausine and about 100 μm in thickness were studied for use as routine dosimeters in radiation processing. These films show basically color bleaching under irradiation with ⁶⁰Co γ-rays in a dose range of 5–50 kGy. The sensitivity of the dosimeters and the linearity of dose-response curves are improved by adding 2.5% of chloral hydrate [CCl₃CH(OH)₂] and 0.15% hydroquinone [HOC₆H₄OH]. These additions extend the minimum dose limit to 1 kGy covering dosimetry requirements of the quality assurance in radiation processing of food and healthcare products. The dose responses of both dyed PVC films at irradiation temperatures from 20°C to 35°C are constant relative to those at 25°C, and the temperature coefficients for irradiation temperatures from 35°C to 55°C were estimated to be (0.43±0.01)%/°C. The dosimeter characteristics are stable within 1% at 25°C before and 60 days after the end of irradiation.     

Determination of Violet Covasol as a cosmetic dye in water samples by a CPE-Scanometry method

The trace amounts of Violet Covasol as a cosmetic dye was determined by an efficient cloud point extraction-Scanometry(CPE-Scanometry) method. This method has many advantages such as novelty,facility, high speed, sensitivity, low cost and safety. The method is based on the CPE of an analyte from an aqueous solution, diluting the extracted surfactant-rich phase with ethanol, transferring to Plexiglas~cell and scanning of the cells containing the analyte solution with a scanner and measuring the RGB parameters with software written in visual basic(VB 6) media. Parameters impacting the extraction efficiency such as p H of the system, the concentration of surfactant, equilibration temperature and time were optimized. Detection limit(DL), relative standard deviation(RSD) and linear range for the proposed method are 0.026, 0.71 and 0.16–6.6 μg m L ~(-1)respectively. The method was successfully applied for the determination of Violet Covasol dye in several water samples, including a water sample containing the dye as a tracer(to investigate subsurface water movement).     

Sol–gel preparation of highly transparent α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> film for the application in red color filter

α-Fe₂O₃ films as inorganic red color filter were synthesized through a simple procedure, epoxide assisted sol–gel route. The sol was prepared through reaction of FeCl₂ in boiling ethanol solution with propylene oxide. The films were formed by the dip-coating of sol on substrate, drying and the following annealing steps. The obtained α-Fe₂O₃ films were composed of homogeneous distributed α-Fe₂O₃ nanoparticles with size of 30–50 nm. The film shows strong absorption to the light below 600 nm and high transparency to the red light (87% at 630 nm). As inorganic red color filter, the optic behavior of this film is nearly as same as the organic color filter made of dye.     

Insight the mechanism of MgAl/layered double hydroxide supported on rubber seed shell biochar for Remazol Brilliant Violet 5R removal

The ever-increasing concentration of Remazol Brilliant Violet 5R discharged mainly from textile industry had cause serious environmental issues towards human and the surrounding ecosystem. Therefore, solving the issue related to dye contamination is seriously important. In this research study, MgAl/layered double hydroxide supported on rubber seed shell biochar (RSSB) had been prepared for Remazol Brilliant Violet 5R (RBV5R) dye adsorption. BET surface area and pore volume of RSSB were found to be 132.40 m²/g and 0.0732 cm³/g, respectively with presence of LDH metals on the RSSB surfaces. The batch adsorption studies showed that RBV5R uptake capacity was significantly enhanced (125.88 mg/g) compared to pristine RSSB (58.69 mg/g) at initial RBV5R concentration, contact time, adsorption temperature and pH of 300 mg/l, 1440 min, 60 °C and pH 2, respectively. The equilibrium and kinetic adsorption data were best fitted into the Freundlich and pseudo-first order model, respectively. The thermodynamic study confirmed the RBV5R adsorption was endothermic in nature and governed by physisorption process. All these findings signified that the MgAl/LDH-RSSB is a promising adsorbent for treating wastewater containing RBV5R dye.     

An optical chemical sensor based on functional polymer films for controlling sulfur dioxide in the air of the working area: Acrylonitrile and alkyl methacrylate copolymers with brilliant green styrene sulfonate

The effects of the chemical and phase composition of acrylonitrile and alkyl methacrylate (Alkyl-MA) copolymers with styrene sulfonates (SS) of triphenylmethane dye cations on the gas permeability and sensing properties of their films were studied for developing an optical chemical sensor (OCS) for sulfur dioxide (SO₂) on the basis of functional polymers. Of the three triphenylmethane dyes tested, namely, fuchsine, Crystal Violet, and Brilliant Green (BG), only the last dye was selected for molecular design. It was shown that the copolymer of Decyl-MA with SS—BG with the degree of modification DM = 0.10 is the best material among the studied ones from the viewpoints of sensitivity, response time, and time stability of sensor characteristics. The conditions for fabricating polymer films and the parameters of their functioning in OCSs for SO₂ were optimized. The effect of annealing conditions on the sensitivity of spectra to SO₂ was studied. Working temperature, working wavelength, and the conditions for the regeneration of the initial spectral parameters were optimized. Calibration characteristics of OCSs for the dynamic admittance of SO₂—air mixtures were obtained. The calculated detection limit for SO₂ in an air flow for a sensor with a sensing film fabricated of the decyl-MA—SS—BG copolymer with DM = 0.10 was 0.16 vol %, or 4160 mg/m³. This points to the necessity of searching for more sensitive sensing materials among other classes of functional polymers.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 3, 2005, pp. 307–315.Original Russian Text Copyright © 2005 by Soborover, Tverskoi, Tokarev.     

Determination of the degradation products of selected sulfonated phenylazonaphthol dyes treated by white rot fungus Pleurotus ostreatus by capillary electrophoresis coupled with electrospray ionization ion trap mass spectrometry

The removal of water-soluble sulphonated phenylazonaphthol dye effluents generated by textile industries is an important issue in wastewater treatment. Microbial treatment of environmental pollutants including dyes, with white rot fungi has received wide attention as a potential alternative for conventional methods in wastewater treatment. Three sulphonated phenylazonaphthol dyes with similar molecular structures Acid Orange 7, Acid Orange 8 and Mordant Violet 5 were selected and degraded by the white rot fungus Pleurotus ostreatus. Chemical instrumental analysis methods such as high-performance liquid chromatography (HPLC) and capillary electrophoresis combined with electrospray ionization mass spectrometry (CE-ESI-MS) were used to identify the degraded dyes. Mordant Violet 5 had two degradation pathways when degraded by P. ostreatus. The first degradation pathway for Mordant Violet 5 was for trans structure and the cis-Mordant Violet 5 followed the second pathway. Acid Orange 8 and Acid Orange 7 had the same degradation mechanism as the first degradation mechanism for Mordant Violet 5, that is cleavage of azo bond at the naphthalene ring side where benzenesulfonic acid and 1,2-naphthoquinone are formed.     

The kinetics study of the reduction of Fast Green dye with cetylpyridinum chloride as cationic surfactant

The kinetics of the reaction of Fast Green dye (FG) with cetylpyridinum chloride was studied in alkaline medium by UV-Visible spectrophotometer. Reduction of Fast Green dye was carried out by varying the fast green dye concentration, cetylpyridinum chloride concentration and concentration of sodium hydroxide. In the present study the reduction of dye was carried out in order to reduce the color content. The interaction of dye was carried out with reducing analyte (cetylpyridinum chloride). The rate of the reaction was determined by varying the above parameters at different temperatures. It was observed that the reduction followed pseudo first-order kinetics with respect to dye, surfactant, OH⁻ ion concentration according to the following reaction pathway. The mechanism for the photo bleaching of the dye has been proposed and well confirmed by the data simulation procedure. The activation parameters of the reaction like entropy of activation (ΔS) and free energy of activation (ΔG) showed the extremely solvated states of transient complex which was less disorderly arranged than the oxidized form of dye, whereas E _a values reflects a high amount of energy required for the reduction of dye with cetylpyridinum chloride.     

Dosimetry characteristics of the nitro blue tetrazolium-polyvinylalcohol film for high dose applications

The dosimetry characteristics of a polyvinylalcohol based radiochromic dye film containing the ditetrazolium salt nitro blue tetrazolium chloride were studied with respect to the potential use of the films for routine dosimetry in radiation processing. The useful dose range for the dosimeter film for gamma and electron irradiation is 5–50 kGy depending on the concentration of the dye. The effects of irradiation temperature and humidity, as well as the stability of the response of the film before and after irradiation, were investigated and determined. Formulations for preparation of the films with different concentrations of the dye and with different pH were tested. The films were also tested in industrial gamma irradiation facilities for process control purposes by comparing their performance with transfer standard dosimeters.     

Enhancement in sensitivity of nitro blue tetrazolium polyvinyl alcohol film dosimeters by sodium formate and Triton X-100

Nitro blue tetrazolium polyvinyl alcohol film dosimeters, NBT-PVA were prepared and evaluated based on radiation-induced reduction of NBT²⁺. NBT-PVA film dosimeters containing different concentrations of NBT dye from 1 to 5 mM were prepared in a solution of ethanol. The dosimeters were irradiated with ?-ray from ⁶⁰Co source at doses up to 50 kGy. UV/vis spectrophotometer was used to investigate the optical density of un-irradiated and irradiated films in terms of absorbance at 529 nm. The absorbance increases with absorbed dose up to 50 kGy for NBT-PVA film dosimeters. The dose sensitivity of NBT-PVA film increases strongly with increase of concentrations of NBT dye. The effects of irradiation temperature, humidity, dose rate and the stability of the response of the films after irradiation were investigated. A considerable increase was observed in the dose response of NBT-PVA film by adding appropriate concentration of sodium formate and Triton X-100.     

Anaerobic biological treatment of dye bearing water in anaerobic sequencing batch reactor: Performance and kinetics studies

Textile and dye industries are main sources of dye bearing effluent. In present studies the anaerobic biological degradation of Acid Red 3BN dye water (AR3BNDW) and mixed dye water (MDW) for reduction of color and COD were studied in sequential batch reactor (SBR). The sludge as sources of microorganism was arranged from maize processing bio methanation wastewater treatment plant, which was acclimatized for treatment of AR3BNDW and MDW. After the acclimatization, dyes degradation were studied in SBR At optimum operation condition of hydraulics retention time (HRT) = 2.5 d, and treatment time (t_R) = 16 h, AR3BNDW have gone maximum 87% color reduction of 500 mg/L dye, and 82.8% COD reduction of 380 mg/L COD. At same operating condition, 84.5% color reduction of 500 mg/L dye, and 79.42% COD reduction of 413 mg/L COD achieved for MDW. The second order Grau model was fitted well for COD and dye reductions. The kinetics parameter were evaluated for both the dye water.     

THE PHOTOKILLING OF BLADDER CARCINOMA CELLS in vitro BY PHENOTHIAZINE DYES

The potential photodynamic therapy photosensitizers Methylene Blue, Azure C, Methylene Violet, Thionine, Methylene Green, Haematoporphyrin, Nile Blue A, chloroaluminium phthalocyanine and bis-aluminium phthalocyanine were examined for their photoeffects and dark toxicity against a human superficial bladder carcinoma cell-line. By examination of [3H]thymidine uptake into dye-treated cells after irradiation with a copper-vapour pumped dye laser, it was found that Methylene Blue was the most phototoxic and dark toxic of all the dyes tested, suggesting that the dye might be of some use as a topically applied photodrug for use in photodynamic therapy of superficial or early-recurring carcinomas.     

The nature of the complexes of 2.2'-dihydroxyazo compounds

The metal complexes of Pontachrome Violet SW, a di-ortho-dihydroxyazo type dye, were studied in an attempt to deduce a reason for the unusual polarographic behavior such as gave rise to the Willard-Dean method for aluminum. Cis-trans isomers, anionic species and azo coordination to the central cation are ruled out. The most likely cause scems to be the rigidity of the complex with the result that the reduction of the complex occurs by a different mechanism then the reduction of the free dye.     

Electrochromic responses of low-temperature-annealed tungsten oxide thin films in contact with a liquid and a polymeric gel electrolyte

Thin films of tungsten trioxide (WO₃) for electrochromic application were synthesized by potentiostatic method by using a peroxytungstic acid as a solution precursor. The morphology of the films with and without postthermal annealing was analyzed by atomic force microscopy. When they were in contact with the liquid electrolyte (LiI in propylene carbonate, PC) and under alternatively applied negative (−1.5 V) and positive (+1.0 V) potentials, the transient optical transmittance modulations at wavelength of 650 nm of the as-deposited and 60 °C annealed WO₃ samples were higher than that of 100 °C annealed WO₃ films, and the switching times between the colored and bleached states were related to the surface morphology of the WO₃ films. In polymeric gel electrolyte (LiI and polymethyl methacrylate in PC) devices, longer time was required for complete coloration as well as bleaching process compared with the liquid one. A parametric analysis was made for each of the transient optical transmittance curves of WO₃-based electrochromic devices to extract the values of the response time in coloration (reduction) and bleaching (oxidation) processes. It concludes that the coloration process was determined by the exchange of current density at the electrolyte–WO₃ interface and a possible inhomogeneous interfacial potential for ion intercalation retards the effective coloration time. The bleaching process seems to be controlled by the space charge-limited lithium ion diffusion in WO₃ electrode and the ionic conductivity of the electrolyte as well.     

Fast and sensitive protein staining with colloidal acid violet 17 following isoelectric focusing in carrier ampholyte generated and immobilized pH gradients

A new method is described for fast and sensitive staining of proteins following isoelectric focusing in carrier ampholyte and immobilized pH gradient polyacrylamide gels. After fixation with trichloroacetic acid the gels are stained for 5-10 min with 0.1-0.2% colloidal Serva Violet 17 (generic name: Acid Violet 17; Color Index No. 42,650) in 10% w/v phosphoric acid. After staining for only 0.5-3 min, major zones, corresponding to 100-500 ng protein, are visible without destaining on a weak background. Detection of minor components requires destaining with 3% w/v phosphoric acid for 5-80 min depending on gel thickness (120-500 microns) and type of support (fabric reinforced versus gels backed to a polyester film). For selected pH marker proteins (bovine serum albumin, carbonic anhydrase, horse myoglobin) a staining sensitivity of 1-2 ng/mm2 protein is found. Dye elution from stained fabric reinforced gels with 50% v/v dioxane-water, followed by absorbance measurements, results in a linear relationship over a range of 1-100 micrograms marker proteins. Staining with collodial Serva Violet 17 is the only method available for fast and high sensitivity and low background staining of immobilized pH gradient gels, without interference from selective dye binding in different pH ranges. Staining with the collodial dye is convenient by avoiding organic solvents with unpleasant vapors and potentially hazardous.