Descoloração e degradação de poluentes orgânicos em soluções aquosas através do processo fotoeletroquímico

Organic compounds responsible for the color of wastewaters are usually refractory to biological digestion. In this paper the photo-assisted electrolysis process is used for color removal from three of the most colored wastewaters, which are daily generated in large amounts: the E1 bleach Kraft mill effluent, a textile reactive dye effluent and a landfill leachate. Electrolysis was carried out at 26,5 mA cm-2 in a flow reactor in which the anode surface was illuminated by a 400 W high pressure Hg bulb. In all experiments 70-75% of color reduction was observed which was also followed by a net organic load oxidation.

Aplicação de fotólise direta e UV/H2O2 a efluente sintético contendo diferentes corantes alimentícios

Food industries employ a lot of synthetic dyes in their products. Most of these dyes are very stable face to the conventional treatments. This work studied the use of advanced oxidation process (AOP) as an alternative to the conventional ones to degrade a synthetic food effluent (photolysis and UV/H2O2 in continuous reactor). The more efficient process was the UV/H2O2 and it presented decoloration and degradation energetic efficiency values equal to 30.775 kWh m-3 and 269.909 kWh m-3, respectively. The color reduction was 96.4% and COD decrease was 38.56%.

Sequential injection analysis (SIA) and response surface methodology: A versatile small volume approach for optimization of photo-Fenton processes

Optimization of photo-Fenton degradation of copper phthalocyanine blue was achieved by response surface methodology (RSM) constructed with the aid of a sequential injection analysis (SIA) system coupled to a homemade photo-reactor. Highest degradation percentage was obtained at the following conditions [H(2)O(2)]/[phthalocyanine] = 7, [H(2)O(2)]/[FeSO(4)] = 10, pH = 2.5, and stopped flow time in the photo reactor = 30 s. The SIA system was designed to prepare a monosegment containing the reagents and sample, to pump it toward the photo-reactor for the specified time and send the products to a flow-through spectrophotometer for monitoring the color reduction of the dye. Changes in parameters such as reagent molar ratios. residence time and pH were made by modifications in the software commanding the SI system, without the need for physical reconfiguration of reagents around the selection valve. The proposed procedure and system fed the statistical program with degradation data for fast construction of response surface plots. After optimization, 97% of the dye was degraded. (C) 2009 Elsevier B.V. All rights reserved.

Applying sequential injection analysis (SIA) and response surface methodology for optimization of Fenton-based processes

This work presents the use of sequential injection analysis (SIA) and the response surface methodology as a tool for optimization of Fenton-based processes. Alizarin red S dye (C.I. 58005) was used as a model compound for the anthraquinones family. whose pigments have a large use in coatings industry. The following factors were considered: [H(2)O(2)]:[Alizarin] and [H(2)O(2)]:[FeSO(4)] ratios and pH. The SIA system was designed to add reagents to the reactor and to perform on-line sampling of the reaction medium, sending the samples to a flow-through spectrophotometer for monitoring the color reduction of the dye. The proposed system fed the statistical program with degradation data for fast construction of response surface plots. After optimization, 99.7% of the dye was degraded and the TOC content was reduced to 35% of the original value. Low reagents consumption and high sampling throughput were the remarkable features of the SIA system. (C) 2008 Published by Elsevier B.V.

Adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface: A spectroscopic study

The adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface at 30 degrees C in the dark was investigated. The color reduction was monitored by spectrophotometry at 503 run. The FTIR and Raman spectra of the Direct Red 23 adsorption as a function of ZnO concentration were registered. From the PM3 semi-empirical calculations of the atomic charge density and dipole moment of the Direct Red 23 molecule, it was demonstrated that the azo, dye molecule may be adsorbed onto the ZnO Surface through molecule geometry modifications, enhancing the interfacial area causing a variation in the bonding frequencies. (C) 2009 Elsevier B.V. All rights reserved.

In vitro evaluation of dental bleaching effectiveness using hybrid lights activation

OBJETIVO: Avaliar se fontes de luz aumentam a eficácia do peróxido de hidrogênio na técnica de clareamento profissional. METODOLOGIA: Foram empregados 60 dentes incisivos bovinos, com dimensões coronárias e radiculares padronizadas a partir do limite amelo-cementário, sendo descartada a porção lingual. Os corpos-de-prova (cp) foram limpos em ultra-som por 20 min e a dentina condicionada com H3PO4 a 38% por 15 s, sendo os (cp) imersos em solução de café solúvel a 25% por duas semanas. A dentina foi impermeabilizada com esmalte e os (cp) divididos em 5 grupos, sendo a cor inicial mensurada através do espectofotômetro-EasyShade (VITA). Todos os (cp) receberam três aplicações por 10 min do gel clareador Opalescence Xtra-Boost (Ultradent) conforme segue: Grupo 1 - controle, não recebeu fotoativação, Grupo 2 - ativado com luz halôgena, Grupo 3 - ativado com LED azul/LASER, Grupo 4 - ativado com LED verde/LASER e Grupo 5 - ativado com LED vermelho. Após o clareamento foi mensurada a variação de cor E, a*, b*e L* e as referentes à escala de cor Vita Clássico. Os dados foram submetidos à análise de variância, teste de Tukey e de Dunn (α=5%). RESULTADOS: A diferença geral da cor foi reduzida quando se empregou LED Azul e Luz Halógena, sendo que o desempenho do peróxido de hidrogênio a 38% foi intensificado dependendo da fonte de luz utilizada. A avaliação quantitativa de cor, obtida por espectrofotômetro e pela escala de cor Vita Clássico, foram coincidentes. CONCLUSÃO: O tipo de fonte de luz empregada interfere na eficácia do agente clareador.

In-Office dental bleaching efficacy assessment in function of the light exposure regime by digital colometric reflectance spectroscopy

In-office dental bleaching has been subject of several studies. Generally those studies quantify through visual analysis, the shade reduction of the teeth submitted to different bleaching protocols (light sources, bleaching agent concentrations and irradiation time). The objective of this work is the determination of the influence of four irradiation protocols on the obtainment of better aesthetic results using a colorimetric spectrophotometer that quantifies color changes in each situation imposed. Forty bovine incisors were selected in function of similar anatomic characteristics; a concentrated coffee solution was used to stain the teeth. A commercial spectrophotometer was used to measure the color changes during evolution of the experiment (stain and bleaching phases) and the obtained data was analyzed by the ANOVA test. The obtained data showed the evolution of teeth color during the staining period, as well as, the color reduction that each bleaching protocol achieved. Based on our findings it is possible to conclude that bleaching protocols with larger irradiation periods did not showed significant differences when compared with shorter irradiation protocols, in that way the use of protocols with 30 min or more of consecutive irradiation are not clinically justified and also can cause several side effects.

Color/race inequalities in oral health among Brazilian adolescents

This study assessed oral health outcomes (perceived dental treatment need, untreated dental caries, gingival bleeding, periodontal pockets, and pain in teeth and gums), in relation to color/race inequalities among adolescents in each Brazilian region. The database included dental examination and interview of 16,833 15-19-year-old adolescents, surveyed by the Brazilian health authority, from May 2002 to October 2003, in accordance with international diagnostic criteria standardized by the World Health Organization. Prevalence ratios estimated by Poisson regression, and controlled by socioeconomic status and access to fluoridated piped water, assessed oral health differentials among color/race groups and country's regions. Except for periodontal pockets, prevalence figures were higher in the North and Northeast: perceived dental treatment needs, untreated dental caries, gingival bleeding at probing and pain in teeth and gums varied between 80-83%, 75-76%, 38-43%, and 17-18%, respectively, in these regions. Adolescents living in the Southeast - the richest Brazilian region - presented a better general profile of oral health than their counterparts living in the remaining regions; they had a lower prevalence of untreated dental caries (54%) and unfavorable gingival status (29%). However, the Southeast presented color/race inequalities in all oral health outcomes, with a poorer profile systematically affecting browns or blacks, depending on the oral health condition under consideration. These results reinforce the need for expanding the amplitude of health initiatives aimed at adolescent oral health. Socially appropriate health programs should concurrently aim at the reduction of levels of oral disease and its inequalities.

Coat color dilution in mice because of inactivation of the melanoma antigen MART-1.

Melanoma antigen recognized by T cells 1 (MART-1) is a melanoma-specific antigen, which has been thoroughly studied in the context of immunotherapy against malignant melanoma and which is found only in the pigment cell lineage. However, its exact function and involvement in pigmentation is not clearly understood. Melanoma antigen recognized by T cells 1 has been shown to interact with the melanosomal proteins Pmel17 and OA1. To understand the function of MART-1 in pigmentation, we developed a new knockout mouse model. Mice deficient in MART-1 are viable, but loss of MART-1 leads to a coat color phenotype, with a reduction in total melanin content of the skin and hair. Lack of MART-1 did not affect localization of melanocyte-specific proteins nor maturation of Pmel17. Melanosomes of hair follicle melanocytes in MART-1 knockout mice displayed morphological abnormalities, which were exclusive to stage III and IV melanosomes. In conclusion, our results suggest that MART-1 is a pigmentation gene that is required for melanosome biogenesis and/or maintenance.

Wood Volume Measurement Using Color Images

Tämä työ käsittelee puutukkien tilavuuden mittaamista värikonenäön avulla. Värikuvat on saatu Simpeleellä olevan metsäteollisuusyrityksen hiomosta. Työssä esitetään perusteellisesti matemaattinen teoria, joka liittyy käytettyihin kuvankäsittelymenetelmiin, kuten luokitteluun, kohinan poistoon ja tukkien segmentointiin. Esitetyt menetelmät implementointiin käytännössä ja eri menetelmillä saatuja tuloksia vertailtiin keskenään. Kuvankäsittelyalgoritmit on implementoitu Matlab 6.0:n avulla. Pääasiassa käytettiin uusinta Image Processing Toolboxia, joka on versio 3.0. Tämä työn näkökulma on pääasiassa käytäntöön soveltava, koska metsäteollsuus on korkealla tasolla Suomessa ja siellä on paljon alan yrityksiä, joissa tässä työssä kehitettyä menetelmää voidaan hyödyntää.

Transference of lutein during cheese making, color stability, and sensory acceptance of prato cheese

The consumption of lutein is associated with the prevention and reduction of age-related macular degeneration. Its incorporation into Prato cheese as a yellowish food coloring is a valid alternative to increase the daily intake of this compound. However, part of the lutein added may be lost in the whey during the cheese making, or it can be degraded by light during storage, resulting in color changes reducing the sensory acceptance of the cheese. The objectives of this study were to determine the transference of the lutein (dye), added to the milk, in the whey, and cheese, to evaluate the effect of the lutein addition, light exposure, and storage time on the cheese color, and to verify the sensory acceptance of Prato cheese with addition of lutein. The lutein recovery of cheese was 95.25%. Color saturation (chrome) increased during storage time resulting in a cheese with more intense color, but there were no changes in the hue of the cheese. Adjusting the amount of lutein added to Prato cheese may lead to greater acceptance. The high recovery of lutein in the cheese and the fact that the hue remained unchanged during storage under light showed that the incorporation of lutein into Prato cheese is feasible from a technical point of view.

Fat reduction in the formulation of frankfurter sausages using inulin and pectin

The aim of this study was to evaluate the influence of different concentrations of inulin and pectin as fat substitutes on the chemical composition, texture, and sensory acceptance of frankfurter sausages. Six treatments were evaluated to test fat replacement: control (T0); low fat control (T1); low fat with 15% inulin (T2); low fat with 30% inulin (T3); low fat with 7.5% inulin and 7.5% pectin (T4); and low fat with 15% inulin and 15% pectin (T5). The addition of fibers increased the yield (T3 and T5; 98.96%), and the color parameters were slightly reduced (T3). Moisture (61.14%) and ashes (6.96%) of sausages with inulin and pectin were higher (T5), while shear force, hardness, fracturability, gumminess, and chewiness (T3 and T5) were slightly lower than those of the control. The addition of inulin (T2) increased the sensory acceptance of the sausages (5.75). Fat can be replaced with inulin and pectin in frankfurter sausages to produce healthy and functional products.

Reduction of oil uptake in deep fat fried chicken nuggets using edible coatings based on cassava starch and methylcellulose

The aim of this study was to evaluate the effect of edible coatings based on methylcellulose (MC) and cassava starch (CS) to reduce oil uptake and improve water retention of chicken nuggets during deep fat frying. Edible coatings were prepared with I g of MC/100 g solution and 4 g of CS/100 g solution, with 25 or 55 g glycerol/100 g biopolymer. These solutions were applied to nugget samples before battering. Pre-fried and fried nuggets were analyzed to determine lipid and water contents. Color and texture were also measured in the fried nuggets. In general, there was no effect of the two concentrations of plasticizer of either of the biopolymers on the water retention of whole nuggets. But, higher oil uptake reduction, and consequently, lower lipid content was observed on nuggets coated with CS and 25% plasticizer. The coated samples were darker and had a brighter yellow color when compared with the control. There was also a significant decrease in the shearing force of the fried coated samples, indicating reduced hardness of these samples.

Electrochemical reduction and determination of Cibacron Blue F3GA at poly-L-lysine modified glassy carbon electrode

The oxidation of a reactive dye, Cibacron Blue F3GA, CB, (C.I. 61211), widely used in the textile industries to color natural fibers, was studied by electrochemical techniques. The oxidation on glassy carbon electrode occurs in two steps at 2.0 < pH < 10 involving one electron transfer each to the amine group leading to the imide derivative. Stable films of poly-L-lysine (PLL) in the presence of glutaraldehyde (GA) 97.5%:2.5% on glassy carbon electrode can be used to detect low levels of dye using its oxidation peak at +0.75V by voltammetry. Linear calibration graphs were obtained for the CB reactive dye, from 1.0 X 10(-6) to 1.0 X 10(-5) mol L-1 in B-R buffer, pH 2.0, using a pre-concentration off-line during 10 min. The detection limit (3 sigma/slope) was calculated to be 4.5 X 10(-8) mol L-1. Films of PLL can readily be applied for the determination of CB dye bearing aminoanthraquinone as chromophore and chlorotriazinyl as reactive group at concentrations at least 100 times lesser than using a glassy carbon electrode without modification. The method described was applied for the determination of CB dye in tap water and raw water collected from the municipal treatment plant with a recovery of 89.2% +/- 5.4 and 88.0% +/- 6.5, respectively. (c) 2005 Elsevier Ltd. All rights reserved.

Evaluation of color removal and degradation of a reactive textile azo dye on nanoporous TiO2 thin-film electrodes

The feasibility of the photobleaching of a textile azo dye, reactive orange 16 (C.I. 17757), in aqueous solution using titanium dioxide thin-film electrodes prepared by the sol-gel method was investigated. The best conditions for maximum photoelectrocatalytic degradation were found to be pH > 10 for Na2SO4 medium and pH < 6 for NaCl. In both situations, an applied potential of +1.0 V and low dye concentration are recommended, when 100% of color removal is obtained after 20 min of photoelectrocatalysis. The effects of side reaction pathway on the degradation rate of dye in sulfate and chloride medium were presented and the best performance are optimized to situations closed to that verified in the textile effluent. The influence of variables as applied potential, pH, supporting electrolyte and dye concentration on the kinetics of photoelectrochemical degradation also were investigated. Oxalic acid is identified by HPLC and UV-Vis spectrophotometric methods as the main degradation product generated after 180 min of photoelectrocatalysis of 4 x 10(-5) mol l(-1) dye in sodium sulphate pH 12 and NaCl pH 4.0 and a maximum reduction of 56 and 62% TOC was obtained, respectively. (C) 2004 Elsevier Ltd. All rights reserved.