1. Cellulose nanofibrils-reinforced pectin membranes for the adsorption of cationic dyes from a model solutionAlenka Ojstršek, Selestina Gorgieva, 2024, original scientific article Abstract: In the presented research, a facile, one-step method for the fabrication of cellulose nanofibrils/pectin (CNFs/PC) membranes is described, which were tested further for their ability to remove cationic dyes from the prepared model solutions. For this purpose, ten membranes were prepared with different quantities of CNFs and PC with/without citric acid (CA) or CaCl2 as mediated crosslinking agents, and they were characterised comprehensively in terms of their physical, chemical, and hydrophilic properties. All the prepared CNFs/PC membranes were hydrophilic with a Water Contact Angle (WCA) from 51.23◦ (without crosslinker) up to 78.30◦ (CaCl2 ) and swelling of up to 485% (without crosslinker), up to 437% (CaCl2 ) and up to 270% (CA). The stability of membranes was decreased with the increase in PC; thus, only four membranes (M1, M2, M3 and M5) were stable enough in water after 24 h, and these were additionally applied in the adsorption trials, using two structurally different cationic dyes, i.e., C.I. Basic Yellow 28 (BY28) and C.I. Basic Blue 22 (BB22), in four concentrations. The highest total surface charge of M3 (2.83 mmol/g) as compared to the other membranes influenced the maximal removal efficiency of both dyes, up to 37% (BY28) and up to 71% (BB22), depending on the initial dye concentration. The final characteristics of the membranes and, consequently, the dye’s absorption ability could be tuned easily by changing the ratio between the CNFs and PC, as well as the type and amount of crosslinker.
Keywords: cellulose nanofibrils, pectin, cationic dyes, adsorption, dye removal
Published in DKUM: 12.03.2024; Views: 320; Downloads: 18
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2. High resolution melting curve analysis for high-throughput SNP genotyping in IL23R gene and association of IL23R with Slovenian inflammatory bowel diseases patientsMitja Mitrovič, Uroš Potočnik, 2010, original scientific article Abstract: Single nucleotide polymorphism (SNP) analysis is important tool in the studies of genetic factors associated with complex diseases and with genetically influenced response to drug therapy (pharmacogenetics). Recently, a new generation of generic dsDNA binding dyes (LCGreen$^{TM}$) contributed to the development of fast and low-cost method for SNP detection and/or genotyping based on high resolution melting (HRM) analysis. The aim of our study was to develop HRM assay for IL23R gene (rs7517847) and to perform association study in Slovenian inflammatory bowel diseases (IBD) patients. We genotyped 345 Slovenian healthy controls and 295 IBD patients including 159 with Crohn's disease (CD) and 136 with ulcerative colitis (UC) for rs7517847 polymorphism in IL23R gene using standard RFLP and optimized HRM methods.
In this study, we showed, that HRM is a simple, fast and reliable method for genotyping of clinical samples where homozygotes (GG and TT) were determined by Tm calling method and difference between homozygotes and heterozygotes was determined by different melting curve shape using gene scanning method. With combination of results from Tm calling and gene scanning methods, we achieved 98,6% concordance between PCR-RFLP and PCRHRM results, based on the analysis of 640 samples. We found statistically significant association of IL23R polymorphism with Slovenian Crohn's disease patients when comparing genotype and allele frequencies between CD patients and controls. Allele frequency of minor allele G was 0,46 in controls and was reduced to 0,33 in CD patients (p < 0,001, OR = 0,588). The frequency of T/T genotype carriers was higher in CD patients (50,3%) than in controls (26,7%, p = 0,002, OR = 2,558). We found weak association between IL23R polymorphism and Slovenian UC patients. Carriers of T/T genotype have higher risk for UC (p = 0,035, OR = 1,599). These results suggest IL23R plays important role in CD and UC development in Slovenian patients.
Keywords: SNP genotyping, high resolution melting, DNA dyes, inflammatory bowel diseases, LC Green Plus
Published in DKUM: 18.08.2017; Views: 1939; Downloads: 112
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3. Dioxins and dioxin-like persistent organic pollutants in textiles and chemicals in the textile sectorBoštjan Križanec, Alenka Majcen Le Marechal, 2006, review article Abstract: Over ▫$7x10^5$▫ tons of dyestuff is produced annually with more than 100.000 commercially available dyes. Synthesis of colorants involves a relatively large group of chemicals with complex syntheses. During the synthesis of colorants, highly toxic, cancerogenic and persistent organic compounds, such as dioxins, can be formed. Dioxins are related to halogenes, chlorine and bromine homologues being the most toxic and persistent. About 40% of globally used colorants contain organically bound chlorine. The use of colorants in textile industry, with their wide applications and complex chemistry could be a significant source of dioxins and/or precursor compounds for the formation of dioxins and other persistent organic pollutants. The aim of the paper is to give an overview of the dioxin-like compounds in chemicals, with emphasis on colorants, textiles and their fate in the environment.
Keywords: textile industry, dioxins, dyes, pigments, textiles, persistent organic pollutants, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans
Published in DKUM: 05.07.2017; Views: 1306; Downloads: 389
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4. A sensitivity model and repeatability of recipe colourBoris Sluban, Olivera Šauperl, 2001, original scientific article Abstract: The paper briefly describes a mathematical model of the colorant mixture colour sensitivity to concentration errors and the numerical estimates of the related quantities. Features of the theoretical model are illustrated with the results of a number of numerical experiments in which the optical data of a few basic dyes applied to textile fabric were used to predict the sensitivities of recipes for sets of target colours spaced regularly in the colour solid. The rest of the article deals with the question whether the predicted values of recipe colour sensitivity provide useful information about the repeatability of recipe colour. The results of a few groups of laboratory experiments involving the textile fabric dyeing with basic dyes have been analysed with this question in mind.
Keywords: textile dyeing, basic dyes, recipe colour, colour, color repeatability, colour sensitivity, concentration errors, mathematical model
Published in DKUM: 05.07.2017; Views: 1258; Downloads: 118
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5. Presence of dioxins in textile dyes and their fate during the dyeing processBoštjan Križanec, Alenka Majcen Le Marechal, Ernest Vončina, Darinka Brodnjak-Vončina, 2005, original scientific article Abstract: Considerable levels of highly toxic polychlorinated dibenzo-p-dioxins (PCCDs) and polychlorinated dibenzofurans (PCDFs) were determined in two among the sixanalysed disperse textile dyes. The dioxin homologue profile of these dyes was similar to that found in some environmental and industrial samples, connected with the textile industry. Dyes contaminated with dioxins were further used in industrial polyester dyeing processes at laboratory scale. We observed the changes in dioxin contents, dioxin transformations and their distribution during the textile dyeing process. After the dyeing and textile finishing processes the content of dioxins was up to fifteen times higher. More than 85% of the total dioxin content was found in dyed polyester. Other 15% was discharged with waste dye bath. Our results confirmed that the presence of dioxins in some textile dyes may be a significant source regardinghuman exposure and environmental contamination.
Keywords: textile dyeing, textile dyes, dioxins, furans, formation, polychlorinated dibenzofurans, polychlorinated dibenzo-p-dioxins
Published in DKUM: 10.07.2015; Views: 1516; Downloads: 121
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6. Decolorization and mineralization of reactive dyes, by the $H_2O_2$/UV process with electrochemically produced $H_2O_2$Tina Jerič, Roel J. M. Bisselink, Willy Van Tongeren, Alenka Majcen Le Marechal, 2013, original scientific article Abstract: Decolorization of Reactive Red 238, Reactive Orange 16, Reactive Black 5 and Reactive Blue 4 was studied in the UV/$H_2O_2$ process with $H_2O_2$ being produced electrochemically. The experimental results show that decolorization increased considerably when switching on the electrochemical production of $H_2O_2$. Complete decolorization (>99%) was achieved for all dyes under the applied experimental conditions, partial mineralization (49-85%) was obtained, which depends on the type of dye. Reactive Red 238 was used to investigate operational parameters and it was found that decolorization was influenced by the applied electrical current of the electrochemical cell and flow rate. Decolorization and mineralization of Reactive Red 238 can be described by pseudo-first order kinetics. It was found that the initial concentration of Reactive Red 238 has a negative influence on the pseudo-firstorder reaction constant.
Keywords: decolorization, hydrogen peroxide, reactive dyes, in-situ $H_2O_2$, AOP, Reactive Red 238
Published in DKUM: 10.07.2015; Views: 1564; Downloads: 81
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7. Reactive dye decolorization using combined ultrasound/H2O2Darinka Brodnjak-Vončina, Alenka Majcen Le Marechal, 2003, original scientific article Abstract: The decolorization of six vinylsulphone reactive dyes (C.I. Reactive Yellow 15, C.I. Reactive Red 22, C.I. Reactive Blue 28, Remazol Dark Black N 150%, C.I. Reactive Blue 220 and C.I. Reactive Black 5) in aqueous solution was investigated using ultrasound and ultrasoundž hydrogen peroxide degradation. Two different concentration levels of hydrogen peroxide were used. The efficiency of the decolorization was evaluated by measuring the absorbance of the dye solutions. The results show that ultrasound treatment was significantly enhanced in the presence of H2O2.
Keywords: ultrasonic irradiation, decolorization, oxidation processes, hydrogen peroxide, reactive dyes, vinylsulphone reactive dyes
Published in DKUM: 01.06.2012; Views: 2377; Downloads: 101
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8. Comparison of H2O2/UV, H2O2/O3 and H2O2/Fe2+ processes for the decolorisation of vinylsulphone reactive dyesTanja Kurbus, Alenka Majcen Le Marechal, Darinka Brodnjak-Vončina, 2003, original scientific article Abstract: Six vinylsulphone reactive dyes were decolorised using three oxidation processes (H2O2/UV, H2O2/O3 and H2O2/Fe2+). The efficiency of decolorisation was measured by decolorisation time, absorbance, COD and TOC and the three methods of decolorisation are compared.
Keywords: textile reactive dyes, vinylsulphone dyes, decolorisation, hydrogen peroxide, UV irradiation, ozone, Fenton's reagent, pollution parameters, experimental design
Published in DKUM: 01.06.2012; Views: 2182; Downloads: 105
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9. Decolorization of textile dyes by whole cultures of Ischnoderma Resinosum and by purified laccase and Mn-peroxidaseVanja Kokol, Aleš Doliška, Ivana Eichlerová, Petr Baldrian, František Nerud, 2007, original scientific article Abstract: Ischnoderma resinosum produced extracellular ligninolytic enzymes laccase and MnP. The activity of laccase achieved the maximum on day 10 (29.4 U L-1), the MnP on day 14 (34.5 U L-1). Laccase and Mn-peroxidase were purified from the culture liquid using gel permeation and ion-exchange chromatographies. Purified Mn-peroxidase performed decolorization of all textile dyes tested (Reactive Black 5, Reactive Blue 19, Reactive Red 22 and Reactive Yellow 15). Laccase was inactive with Reactive Black 5 and Reactive Red 22, while all dyes were decolorized after addition of the redox mediators violuric acid (VA) and hydroxybenzotriazole (HBT). The culture liquid from I. resinosum cultures was also able to decolorize all dyes as well as the synthetic dyebaths in the presence of VA and HBT. The highest decolorization rates were detected in acidic pH (3-4).
Keywords: Ischnoderma resinosum, Basidiomycetes, Laccase, Mn-peroxidase, Textile dyes, ligninolytic enzymes
Published in DKUM: 01.06.2012; Views: 1971; Downloads: 90
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10. Residual dyebath purification using a system of constructed wetlandAlenka Ojstršek, Darinka Fakin, Danijel Vrhovšek, 2007, original scientific article Abstract: A constructed wetland model, comprising two different substrate mixtures, was used to purify textile dyebath wastewater. Three laboratory prepared wastewaters containing three commercial dyes of different classes and chemicalconstitution (one vat and two reactive dyes), different chemicals (NaOH, NaCl) and auxiliaries (migration inhibitor, sequestering, defoaming andwetting agents) were employed. Purifying efficiency was verified by measuring pollution parameters, such as absorbance, pH, total organic carbon (TOC), chemical oxygen demand (COD) and electrical conductivity (EC). It was found that the constructed wetland model reduced dye concentration by up to 70%, lowered the TOC and COD values up to 88%, electrical conductivity up to 60% and pH from 12 to 7.6.
Keywords: textile dyeing, reactive dyes, vat dyes, wastewater treatment, constructed wetland model, biological treatment, purification
Published in DKUM: 01.06.2012; Views: 2315; Downloads: 99
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