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Analysis of reactive dyestuffs and their hydrolysis by capillary electrophoresis
Alenka Ojstršek, Aleš Doliška, Darinka Fakin, 2008, izvirni znanstveni članek

Opis: The objective of the presented research was to examine the potential of capillary electrophoresis (CE) for the analysis of structurally different reactive dyestuffs, their activation and posterior hydrolysis, with special focus on optimization of the working conditions. Preliminary, the effect of various additives to the background electrolyte on the resolution improvements versus migration time of Reactive Black 5 as a model dyestuff was investigated. Based on these results, the electropherograms of eight commercially interesting reactive dyestuffs of various chemical structures and their converted forms upon alkaline pH were carried-out. In order to examine the behavior of the reactive dyestuff during the dyeing process, the dye-bath absorbance was monitored throughout the Reactive Black 5 exhaustion, and the conversion of the dye's form was highlighted using the CE technique. The obtained results unequivocally prove that CE could offer a fast and efficient detection method of structurally different reactive dyestuffs, as well as their hydrolysis products in the dye-baths and effluents later on.
Ključne besede: capillary electrophoresis, dyes, hydrolysis
Objavljeno: 31.05.2012; Ogledov: 676; Prenosov: 1
URL Polno besedilo (0,00 KB)

Removal of vat and disperse dyes from residual pad liquors
Vera Golob, Alenka Ojstršek, 2005, izvirni znanstveni članek

Opis: The efficiency of three wastewater treatment techniques, coagulation/flocculation, adsorption and ultrafiltration, has been studied for the removal of vat and disperse dyes from residual pad liquors. Three inorganic coagulants Al2(SO4)3 18H2O, FeSO4 7H2O, FeCl3 6H2O and commercial cationic flocculant, as individuals and in combination, were tested for the coagulation/flocculation methods. Granular activated carbon was used as an adsorbent in the adsorption technique. Ultrafiltration was performed using a polyethersulfone membrane with a molecular weight cut-off of 10 kDa. Dye removal was evaluated as the difference between concentrations of dyes in pad liquors before and after a particular treatment using absorbance measurements.The obtained results indicated over 90% of dye removal using appropriate coagulants and only 40% using activated carbon. The best results, dye removal over 98%, were achieved using the ultrafiltration technique.
Ključne besede: textile dyeing, disperse dyes, wastewater, decoloration, wastewater treatment, coagulation, flocculation, adsorption, ultrafiltration, vat dyes
Objavljeno: 01.06.2012; Ogledov: 926; Prenosov: 1
URL Polno besedilo (0,00 KB)

Wastewater treatment after reactive printing
Sonja Šostar-Turk, Marjana Simonič, Irena Petrinić, 2005, izvirni znanstveni članek

Opis: Membrane filtration of wastewater after textile printing with reactive dyes isdescribed. The wastewater from a Slovenian factory, whose output is approx. 80% reactive dyes printed and dyed on cotton, was studied. In particular, the presence of urea, sodium alginate, oxidation agent and reactive dyes, used forthe printing paste preparation, in the wastewater was studied. Chemical analyses of actual, non-purified, wastewater showed that many Slovenian regulations were exceeded. The study of membrane filtration is based on a pilot wastewater treatment plantČ ultrafiltration (UF) and reverse osmosis (RO) units. The quality of the wastewater was improved by ultrafiltration, butits effluent still does not conform to the specification of concentration limits for emission into water. Permeate coming from RO meets the required specification and, therefore, could be re-used in the washing process of printed textiles.
Ključne besede: textile printing, reactive dyes, wastewater treatment, membrane filtration, pilot plant
Objavljeno: 01.06.2012; Ogledov: 1030; Prenosov: 5
URL Polno besedilo (0,00 KB)

Ultrasound in textile dyeing an the decolouration/mineralization of textile dyes
Simona Vajnhandl, Alenka Majcen Le Marechal, 2005, pregledni znanstveni članek

Opis: In recent decades ultrasound has established an important place in different industrial processes such as the medical field, and has started to revolutionize environmental protection. The idea of using ultrasound in textile wet processes is not a new one. On the contrary there are many reportsfrom the 1950s and 1960s describing the beneficial effects of ultrasound in textile wet processes. The aim of this paper is to review some fundamentals of ultrasound, its broad application and gather some new researchand studies regarding ultrasound application in textile wet processes,with the emphasis on textile dyeing and the decolouration/mineralization of textile wastewaters.
Ključne besede: textile industry, textile dyes, wastewater, decoloration, degradation, ultrsound
Objavljeno: 01.06.2012; Ogledov: 655; Prenosov: 7
URL Polno besedilo (0,00 KB)

Efficiency of the coagulation/flocculation method for the treatment of dyebath effluents
Vera Golob, Aleksandra Vinder, Marjana Simonič, 2005, izvirni znanstveni članek

Opis: Textile dyeing processes are among the most environment-unfriendly industrial processes, because they produce coloured wastewaters that are heavily polluted with dyes, textile auxiliaries and chemicals. The coagulation/flocculation method was studied as a wastewater treatment technique for the decolourization of residual dyebath effluents after dyeing cotton/polyamide blends using reactive and acid dyes. It was discovered that acombination of aluminium sulphate and a cationic organic flocculant yields an effective treatment for residual dyebath wastewaters since almost complete decolourization was achieved, TOC, COD, AOX, BOD and the anionic surfactants were reduced and the biodegradability was increased.
Ključne besede: textile industry, reactive dyes, acid dyes, wastewater, čiščenje odpadnih vodwastewater treatment, flocculation, coagulation, ecological analyses, wastewater decoloration, Jar-tests
Objavljeno: 01.06.2012; Ogledov: 951; Prenosov: 5
URL Polno besedilo (0,00 KB)

Textile finishing industry as an important source of organic pollutants
Alenka Majcen Le Marechal, Boštjan Križanec, Simona Vajnhandl, Julija Volmajer Valh, 2012, samostojni znanstveni sestavek ali poglavje v monografski publikaciji

Ključne besede: textile finishing industry, organic pollutants, organic dyes, textile wastewater
Objavljeno: 01.06.2012; Ogledov: 791; Prenosov: 3
URL Polno besedilo (0,00 KB)

Ecological alternatives to the reduction and oxidation processes in dyeing with vat and sulphur dyes
Mojca Božič, Vanja Kokol, 2008, pregledni znanstveni članek

Opis: This article gives a summary of the most commonly used ecologically unfriendly processes for the reduction and oxidation of vat and sulphur dyes. It also describes the new alternatives that are in the development stage and could be important in the near future. Sodium dithionite as the dominant reducing agent produces large amounts of sodium sulphate, and also toxic sulphite and thiosulphate as by-products. Consequently, high amounts of hydrogen peroxide and alkali are required for the treatment of effluents, which add to the cost of the process. Attempts have been made to use organic biodegradable reducing agents, enzymes, catalytic hydrogenation, and also indirect or direct, electrochemical reductive methods that employ a redox mediator (electron-carrier). The reduction has also been carried out via the dye radical molecule or, in the case of indigo, by direct electrochemical reduction using graphite as the electrode material. Physical techniques, for example using ultrasound, magnetic fields or UV have been shown to be effective only when used to accelerate methods using classical reduction and oxidation processes. However, although these methods offer some environmental benefits, there is still no satisfactory alternative reducing and/or oxidising agent available today.
Ključne besede: textile dyeing, vat dyes, sulphur dyes, reduction, oxidation, catalysis, ecology, organic agents, electrochemistry, ultrasound, magnetic field, UV application, biotechnology
Objavljeno: 01.06.2012; Ogledov: 725; Prenosov: 7
URL Polno besedilo (0,00 KB)

[Beta]-cyclodextrin as a retarding reagent in polyacrylonitrile dyeing
Bojana Vončina, Vera Vivod, Darja Jaušovec, 2007, izvirni znanstveni članek

Opis: ß-Cyclodextrin was tested as a dye complexing agent - as a dye retardant in the dyeing of PAN fibres with cationic dyes. Significant improvement of colouruniformity and some improvements in colour depth were observed when PAN fibres were dyed in the presence of ß-cyclodextrin as compared to dyeing in the presence of a commercial retardant.
Ključne besede: textile dyeing, cationic dyes, cyclodextrin, polyacrylonitrile fibres, complexation
Objavljeno: 01.06.2012; Ogledov: 722; Prenosov: 3
URL Polno besedilo (0,00 KB)

Case study of the sonochemical decolouration of textile azo dye Reactive Black 5
Simona Vajnhandl, Alenka Majcen Le Marechal, 2007, izvirni znanstveni članek

Opis: The decolouration and mineralization of reactive dye C.I. Reactive Black 5, a well-known representative of non-biodegradable azo dyes, by means of ultrasonic irradiation at 20, 279 and 817 kHz has been investigated with emphasis on the effect of various parameters on decolouration and degradation efficiency. Characterization of the used ultrasound systems was performed using calorimetric measurements and oxidative species monitoring using Fricke and iodine dosimeter. Experiments were carried out with low frequency probe type, and a high-frequency plate type transducer at 50, 100 and 150 W of acoustic power and within the 5-300 mgžL initial dye concentration range. Decolouration, as well as radical production, increased with increasing frequency, acoustic power, and irradiation time. Any increase in initial dye concentration results in decreased decolouration rates. Sonochemical decolouration was substantially depressed by the addition of 2-methyl-2-propanol as a radical scavenger, which suggests radical-induced reactions in the solution. Acute toxicity to marine bacteria Vibrio fischeri was tested before and after ultrasound irradiation. Under the conditions employed in this study, no toxic compounds were detected after 6 h of irradiation. Mineralization of the dye was followed by TOC measurements. Relatively low degradation efficiency (50% after 6 h of treatment) indicates that ultrasound is rather inefficient in overall degradation, when used alone.
Ključne besede: textile industry, wastewater treatment, textile dyeing, reactive dyes, azo dyes, decoloration, ultrasound, degradation, decoloration kinetics, oxidizing species
Objavljeno: 01.06.2012; Ogledov: 826; Prenosov: 2
URL Polno besedilo (0,00 KB)

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