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Advanced oxidation processes for decolorization of aqueous solution containing acid red G azo dye

100%
Surpăţeanu M., Zaharia C.
Open Chemistry
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2004
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vol. 2
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issue 4
573-588
EN
Some investigations concerning the decolorization of Acid Red G azo dye by photooxidation with hydrogen peroxide were performed. The influences of pH, oxidant concentration, and the presence of Fe2+ or other metal ions (Co2+, Cu2+, Ni2+, Mn2+) as potential catalysts, were investigated. The best results were obtained in the presence of ferrous ions in acid and neutral media. The other ions are not as effective as Fe2+ for dye decolorization. Co2+ and Cu2+ ions have a catalytic action, at low concentration, within a wide range of pH. Ni2+ and Mn2+ ions have no catalytic effect in photooxidation with hydrogen peroxide at acid Ni2+ and Mn2+ ions have no catalytic effect in photooxidation with hydrogen peroxide at acid pH values, but show a weak action in alkaline media.
2
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A novel laccase from fresh fruiting bodies of the wild medicinal mushroom Tricholoma matsutake

100%
Xu L., Zhu M., Chen X., Wang H., Zhang G.
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issue 1
35-40
EN
The knowledge about biological activities of constituents from medicinal mushrooms belonging to the genus Tricholoma is limited. A 59-kDa laccase has now been purified from fresh fruiting bodies of the mushroom Tricholoma matsutake. The purification protocol entailed ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-cellulose, affinity chromatography on ConA-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. Of the various affinity and ion exchange chromatographic media employed, the laccase bound only on Con A-Sepharose. The activity of the laccase did not undergo major changes over the temperature range 20-80°C. However, all activity vanished following exposure to 100°C for 10 minutes. The enzyme activity varied only slightly over the pH range 3-5, with the optimal pH of 5, but exhibited a precipitous decline when the pH was increased to 6, and was undetectable at pH 8 and 9. The laccase showed activity in the decolorization of azo dyes without a mediator. Its N-terminal sequence demonstrated only slight resemblance to those of other mushroom laccases. The newly described laccase is distinctive from the previously isolated Tricholoma mushroom laccases in a number of aspects.
3
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Novel laccase-like multicopper oxidases from the Myrothecium roridum fungus - production enhancement, identification and application in the dye removal process

100%
Jasińska A., Góralczyk A., Soboń A., Długoński J.
Acta Biochimica Polonica
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2018
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vol. 65
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issue 2
287-295
EN
The aim of this study was to overproduce, identify and apply novel laccase-like multicopper oxidases (LMCOs) from Myrothecium roridum in a dye removal process. LMCOs' production was enhanced by modifying the medium and adding copper ions. After purification, two proteins, LMCO1 and LMCO2, with molecular masses of 46.7 and 66.3 kDa were discovered. Peptide analysis by mass spectrometry revealed that they belong to the cupredoxin superfamily. Characteristic peptide sequences were obtained for MCOs and bilirubin oxidases. Crude enzymes were applied in a dye decolorization process. Supplementation with 1 mM of vanillin allowed an almost complete elimination of the Indigo carmine within 3 hours. The dye was removed from a solution containing metals, surfactants and organic solvents. The in-gel assessment of the activity and decolorization ability of MCOs, followed by protein extraction and SDS-PAGE, confirmed that only LMCO2 was responsible for the dye removal. MCOs produced by Myrothecium sp. have been poorly studied before. The obtained results broaden knowledge on this subject and may contribute to the development of an eco-friendly method of dye elimination.
4
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Application of Fenton's Reagent in the Textile Wastewater Treatment Under Industrial Conditions

72%
Ledakowicz S., Bilińska L., Żyłła R.
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vol. 19
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issue 2
163-174
EN
Application of reactive dyes is very popular in textile industry as these dyestuffs are characterized by good fastness properties. Constapel et al in 2009 estimated the production of this type of dyes for over 140,000 Mg/year. The reactive dyes are mostly (50%) employed for coloration of cellulosic fibers, however they can also be applied on wool and nylon. Unfortunately, they possess a low degree of fixation (50÷90%), since the functional groups also bond to water, creating hydrolysis and the excess of dyes applied cause a colored pollution of aqueous environment. Moreover, dyeing process requires the use of: electrolytes in the form of aqueous solutions of NaCl or Na2SO4 in the concentration up to 100 g/dm3, alkaline environment (pH > 10) and textile auxiliary agents (including detergents). Therefore, the wastewater generated during the reactive dyeing processes is characterized by high salinity, pH value and color, and due to low value of the BOD5/COD ratio are nonbiodegradable. The successful methods of textile wastewater treatment could be Advanced Oxidation Processes (AOPs), amongst which the Fenton reagent seems to be most promising as it is the cheapest and easy in use. Based on the newest literature survey it was found that many successful tests with Fenton reaction were performed mainly in decolorization. However, not enough attention was devoted to decolorization of real industrial wastewater containing dyes, detergents and salts NaCl, or Na2SO4. The experiments carried out in a laboratory scale were focused on the impact of NaCl and textile auxiliary agent (liquid dispersing and sequestering agent) on an inhibition of decolorization process by Fenton's reagent. The objects of the investigation were synthetic mixtures simulating the composition of real textile wastewater as well as the real industrial wastewater generated in the reactive dyeing. The inhibition of the Fenton decolorization in the presence of NaCl and liquid dispersing and sequestering agent was demonstrated. Additional experiments using pulse radiolysis were carried out in order to confirm the inhibition of chloride in the decolorization process.
PL
Stosowanie barwników reaktywnych jest bardzo popularne w przemyśle włókienniczym ze względu na fakt, że barwniki te charakteryzują się dobrą odpornością uzyskiwanych wybarwień. W 2009 roku Constapel et al oszacowali, że produkcja tego typu barwników sięga ponad 140 000 Mg/rok. Barwniki reaktywne są w większości (50%) stosowane do barwienia włókien celulozowych, jednakże mogą one być również stosowane do wełny i poliamidu. Niestety, barwniki te mają niski stopień związania z włóknem (50÷90%), co powoduje znaczące zabarwienie ścieków. Ponadto, proces barwienia wymaga stosowania: elektrolitów w postaci wodnych roztworów NaCl i Na2SO4 w stężeniu do 100 g/dm3, środowiska zasadowego (pH > 10) i włókienniczych środków pomocniczych (w tym detergentów). Dlatego też ścieki wytwarzane podczas procesów barwienia reaktywnego charakteryzują się wysokim zasoleniem i pH oraz intensywnym zabarwieniem, a ze względu na niską wartość stosunku BZT5/ChZT nie są one biodegradowalne. Skuteczną metodą oczyszczania ścieków włókienniczych może być zastosowanie procesów pogłębionego utleniania (AOPs), wśród których odczynnik Fentona wydaje się być najbardziej obiecujący, gdyż jest najtańszy i łatwy w użyciu. Na podstawie najnowszych danych literaturowych stwierdzono, że w wielu badaniach z użyciem odczynnika Fentona zajmowano się głównie odbarwianiem roztworów barwników. Jednak zbyt mało uwagi poświęcono odbarwianiu rzeczywistych ścieków włókienniczych, zawierających barwniki, detergenty i sole (NaCl i Na2SO4). Eksperymenty przeprowadzone w skali laboratoryjnej były ukierunkowane na analizę inhibitującego wpływu NaCl i włókienniczych środków pomocniczych (środki dyspergujące i sekwestrujące) na proces odbarwiania odczynnikiem Fentona. Przedmiotem badań były syntetyczne ścieki symulujące skład rzeczywistych ścieków włókienniczych, jak również rzeczywiste ścieki powstałe w procesie barwienia reaktywnego. Wykazano zjawisko hamowania odbarwiania odczynnikiem Fentona w obecności NaCl, a także środków powierzchniowo czynnych. Wykonano dodatkowe eksperymenty z wykorzystaniem radiolizy impulsowej w celu potwierdzenia wpływu obecności jonów chlorkowych na hamowanie procesu odbarwiania.
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