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The textile industry discharges up to 5 % of their dyes in aqueous effluents. Here, use of spent mushroom substrate (SMS) of commercial white button mushroom production and its aqueous extract, SMS tea, was assessed to remove textile dyes from water. A total of 30-90 % and 5-85 % of the dyes was removed after a 24 h incubation in SMS and SMS tea, respectively. Removal of malachite green and remazol brilliant blue R was similar in SMS and its tea. In contrast, removal of crystal violet, orange G, and rose bengal was higher in SMS, explained by sorption to SMS and by the role of non-water-extractable SMS components in discoloration. Heat-treating SMS and its tea, thereby inactivating enzymes, reduced dye removal to 8-58 % and 0-31 %, respectively, indicating that dyes are removed by both enzymatic and non-enzymatic activities. Together, SMS of white button mushroom production has high potential to treat textile-dye-polluted aqueous effluents.

Laccases are multicopper oxidases able to oxidize several phenolic compounds and find application in numerous industrial applications. Among laccase producers, white-rot fungi represent a valuable source of multiple isoforms and isoenzymes of these multicopper oxidases. Here we describe the identification, biochemical characterization, and application of laccase 2 from Trametes polyzona (TP-Lac2), a basidiomycete fungus emerged among others that have been screened by plate assay. This enzyme has an optimal temperature of 50 degrees C and in acidic conditions it is able to oxidize both phenolic and non-phenolic compounds. The ability of TP-Lac2 to decolorize textile dyes was tested in the presence of natural and synthetic mediators at 30 degrees C and 50 degrees C. Our results indicate that TP-Lac2 most efficiently decolorizes (decolorization rate > 75%) malachite green oxalate, orange G, amido black10B and bromocresol purple in the presence of acetosyringone and 2,2 '-azinobis (3-ethylbenzthiazoline-6-sulfonate)-ABTS. Overall, the laccase mediator system consisting of TP-Lac2 and the natural mediator acetosyringone has potential as an environmentally friendly alternative for wastewater treatment in the textile industry.

Dyes are coloring agents widely used in the textile and leather industries. Synthetic dyes are the major contributor to global wastewater exhibiting toxic effects on humans, aquatic organisms, and the environment. The conventional decolorization treatments are less effective due to high dye concentration in wastewater, complex chemical structure, and poor biodegradability. Several strategies like physical, chemical, and biological were reported earlier for dye decolorization. However, the adsorption technique has been extensively considered from economic and ecological standpoints. Biochar, a carbonaceous material generated by pyrolyzing waste biomass has been discussed here to tackle the dye-containing wastewater. As an adsorbent, biochar has gained considerable attention owing to its underlying advantages like larger surface area, high porosity, low production cost, varied surface functional groups, easy surface modifications, exceptional hydrophobicity, and aromaticity. In this chapter, we have discussed approaches for the production, and characterization of the biochar. Furthermore, we have also considered the effect of different physicochemical properties, sorption kinetics, isotherm models, and other key factors affecting the sorption mechanism. In this perspective, an effort has been made in this chapter to explore the probability and practicability of biochar as a sorbent for removal of the textile dyes., Part of ISBN 9780323912358 9780323998161QC 20230725

Elektrode modifikovane kompozitom PbO2 sa grafitnim ugljen-nitridom (GCN) upotrebljene su za elekrohemijsku degradaciju tekstilne boje Reactive Black 5. Modifikovana čelična elektroda je korišćena kao anoda, a kao katoda čista čelična elektroda. Ispitan je uticaj strukture PbO2 na elektrokatalitičke karakteristike elektroda. Morfologija materijala je ispitana SEM-om, TEM-om i XRD-om, dok su elektrohemijske osobine ispitane uz pomoć CV i EIS merenja. Efikasnost degradacije je praćena UV-Vis spektrofotometrijom i tečnom hromatografijom. Pri optimalnim parametrima pH, koncentracije pomoćnog elektrolita, jačine struje i koncentracije ispitivane boje, najbolji rezultati su dobijeni sa elektrodom gde je cetiltrimetilamonijum-bromid (CTAB) korišćen kao templat za sintezu PbO2. Pod ovim uslovima je postignuta potpuna degradacija nakon 60 min tretmana, a proizvodi degradacije su određeni korišćenjem HPLC-MS/MS metode., Electrodes modified by PbO2 and graphite carbon nitride (GCN) composite were used for electrochemical degradation of Reactive Black 5 textile dye. A modified steel electrode was used as the anode, while a pure steel electrode was used as the cathode. The influence of PbO2 structre on electrocatalytic characteristics of electrodes was investigated. The morphology of the material was examined by SEM, TEM and XRD, while the electrochemical properties were analyzed using means of CV and EIS measurements. The degradation efficiency was monitored by UV-Vis spectrophotometry and liquid chromatography. At optimal pH parameters, supporting electrolyte concentration, current strength and test dye concentration, the best results were obtained with an electrode where cetyl trimethyl ammonium bromide (CTAB) was used as a template for PbO2 synthesis. Under these conditions, complete degradation was achieved after 60 min of treatment, and degradation products were determined using the HPLC-MS/MS method.

Elektrode modifikovane kompozitom PbO2 sa grafitnim ugljen-nitridom (GCN) upotrebljene su za elekrohemijsku degradaciju tekstilne boje Reactive Black 5. Modifikovana čelična elektroda je korišćena kao anoda, a kao katoda čista čelična elektroda. Ispitan je uticaj strukture PbO2 na elektrokatalitičke karakteristike elektroda. Morfologija materijala je ispitana SEM-om, TEM-om i XRD-om, dok su elektrohemijske osobine ispitane uz pomoć CV i EIS merenja. Efikasnost degradacije je praćena UV-Vis spektrofotometrijom i tečnom hromatografijom. Pri optimalnim parametrima pH, koncentracije pomoćnog elektrolita, jačine struje i koncentracije ispitivane boje, najbolji rezultati su dobijeni sa elektrodom gde je cetiltrimetilamonijum-bromid (CTAB) korišćen kao templat za sintezu PbO2. Pod ovim uslovima je postignuta potpuna degradacija nakon 60 min tretmana, a proizvodi degradacije su određeni korišćenjem HPLC-MS/MS metode., Electrodes modified by PbO2 and graphite carbon nitride (GCN) composite were used for electrochemical degradation of Reactive Black 5 textile dye. A modified steel electrode was used as the anode, while a pure steel electrode was used as the cathode. The influence of PbO2 structre on electrocatalytic characteristics of electrodes was investigated. The morphology of the material was examined by SEM, TEM and XRD, while the electrochemical properties were analyzed using means of CV and EIS measurements. The degradation efficiency was monitored by UV-Vis spectrophotometry and liquid chromatography. At optimal pH parameters, supporting electrolyte concentration, current strength and test dye concentration, the best results were obtained with an electrode where cetyl trimethyl ammonium bromide (CTAB) was used as a template for PbO2 synthesis. Under these conditions, complete degradation was achieved after 60 min of treatment, and degradation products were determined using the HPLC-MS/MS method.

A continuous compact membrane bioreactor consisted of ceramic-supported graphene oxide membrane (CSGoM) was implemented for the first time for anaerobic biodecolorization of monoazo Acid Orange 7 (AO7), diazo Reactive Black 5 (RB5), and triazo Direct Blue 71 (DB71) solutions, showing excellent decolorization potential. The membrane was prepared by vacuum filtration of various graphene oxide solutions using a UF ceramic flat element. The decolorization efficiency of the CSGoM bioreactor, made from 1 mg·mL?1 of GO solution (B-CSGoM-1), was investigated for several structurally distinct azo dyes, initial feed concentrations, and permeate fluxes. Maximum color removal was achieved under low feed concentration (50 mg·L?1) and permeate flux (0.05 L·m?2·h?1), reaching 99% for AO7, 96% RB5, and 92% for DB71. At this low permeate flux, the biodecolorization was stable for all azo dye solutions irrespective of the feed concentration. In a subsequent experiment under higher feed concentration and permeate flux (100 mg·L?1 and 0.10 L·m?2·h?1), the decolorization slightly fell to 93%, 85%, and 81% for monoazo, diazo, and triazo solutions, respectively. The existence of anaerobic bacteria (Geobacter and Pseudomonas guangdongensis) in the B-CSGoM-1 biofilm confirms that they could perform efficient biodegradation of azo dye molecules in association with the graphene oxide membrane. © 2021 The Authors

The nature is abode to numerous plants, animal and mineral resources that offersustainable alternative to chemicalsused in textile dyeing. In this paper an effort has been made to utilize the roots of Himalayan nettle plant for fabric dyeing which grows abundantly in-the higher altitude of Uttarakhand as a weed plant. The extraction and dyeing variables were optimized for application on silk fabric on the basis of colour strength and wash fastness rating. Dye extraction carried out in aqueous medium at simmering temperature for 1.5 hoursresulted in better colour depth and washing fastness. Similarly, dyeing of silk at 90ºC for 90 minutes using 3 gm per 100 ml powdered dye material yielded better dyed samples in terms of colour strength and wash fastness. The obtained dye recipe is easy to be used by dyeing units at minimal cost since no chemicals are added during dyeing and raw material can be collected from pastures, around croplands and nearby forest areas.

The nature is abode to numerous plants, animal and mineral resources that offersustainable alternative to chemicalsused in textile dyeing. In this paper an effort has been made to utilize the roots of Himalayan nettle plant for fabric dyeing which grows abundantly in-the higher altitude of Uttarakhand as a weed plant. The extraction and dyeing variables were optimized for application on silk fabric on the basis of colour strength and wash fastness rating. Dye extraction carried out in aqueous medium at simmering temperature for 1.5 hoursresulted in better colour depth and washing fastness. Similarly, dyeing of silk at 90ºC for 90 minutes using 3 gm per 100 ml powdered dye material yielded better dyed samples in terms of colour strength and wash fastness. The obtained dye recipe is easy to be used by dyeing units at minimal cost since no chemicals are added during dyeing and raw material can be collected from pastures, around croplands and nearby forest areas.

The nature is abode to numerous plants, animal and mineral resources that offersustainable alternative to chemicalsused in textile dyeing. In this paper an effort has been made to utilize the roots of Himalayan nettle plant for fabric dyeing which grows abundantly in-the higher altitude of Uttarakhand as a weed plant. The extraction and dyeing variables were optimized for application on silk fabric on the basis of colour strength and wash fastness rating. Dye extraction carried out in aqueous medium at simmering temperature for 1.5 hoursresulted in better colour depth and washing fastness. Similarly, dyeing of silk at 90ºC for 90 minutes using 3 gm per 100 ml powdered dye material yielded better dyed samples in terms of colour strength and wash fastness. The obtained dye recipe is easy to be used by dyeing units at minimal cost since no chemicals are added during dyeing and raw material can be collected from pastures, around croplands and nearby forest areas.

The nature is abode to numerous plants, animal and mineral resources that offersustainable alternative to chemicalsused in textile dyeing. In this paper an effort has been made to utilize the roots of Himalayan nettle plant for fabric dyeing which grows abundantly in-the higher altitude of Uttarakhand as a weed plant. The extraction and dyeing variables were optimized for application on silk fabric on the basis of colour strength and wash fastness rating. Dye extraction carried out in aqueous medium at simmering temperature for 1.5 hoursresulted in better colour depth and washing fastness. Similarly, dyeing of silk at 90ºC for 90 minutes using 3 gm per 100 ml powdered dye material yielded better dyed samples in terms of colour strength and wash fastness. The obtained dye recipe is easy to be used by dyeing units at minimal cost since no chemicals are added during dyeing and raw material can be collected from pastures, around croplands and nearby forest areas.

The main goal of this work was to prove that nickel containing Al,Fe pillared bentonites have enhanced catalytic properties. The chosen test system was the catalytic wet peroxide oxidation (CWPO) the Acid Yellow 99 dye (AY99) with the initial concentration of 50 mg dm(-3), the amount of H2O2 that exceeded the stoichiometric one, 60 A degrees C, magnetic stirrer, atmospheric pressure. Bentonite was successfully pillared with AlFe and AlFeNi polyoxo cations. The chemical composition of the synthesized samples was: SiO2 56.5, Al2O3 31.3, Fe2O3 9.2; SiO2 56.4, Al2O3 31.9, Fe2O3 8.9 and NiO 0.1; SiO2 61.1, Al2O3 31.3, Fe2O3 4.8 and NiO LT 0.01 for AlFe10-PILC, AlFe10Ni5-PILC and AlFe5Ni5-PILC, respectively. The values of textural property parameters decreased in the following order AlFe10-PILC > AlFe10Ni5-PILC > AlFe5Ni5-PILC. Almost complete decolorization was achieved using all synthesized catalysts and followed first order kinetics. AlFe10Ni5-PILC induced the highest decolorization rate. Somewhat higher decolorization rate in the presence of AlFe10Ni5-PILC in comparison with AlFe5Ni5-PILC can probably be ascribed to one of the following properties or their combined effect: higher Fe content and more developed porous structure. Adsorption of AY99 on AlFe5Ni5-PILC and its degradation by H2O2 (without catalyst) were investigated in order for their influence on the decolorization of AY99, in comparison with that of CWPO using AlFe10Ni5-PILC, to be estimated. The adsorption was the least efficient, followed by degradation using H2O2 (without catalyst). CWPO was more efficient when compared to adsorption and degradation by H2O2 together. CWPO using Al,Fe,Ni-PILC can be regarded as promising method for degradation of azo dyes.

The main goal of this work was to prove that nickel containing Al,Fe pillared bentonites have enhanced catalytic properties. The chosen test system was the catalytic wet peroxide oxidation (CWPO) the Acid Yellow 99 dye (AY99) with the initial concentration of 50 mg dm(-3), the amount of H2O2 that exceeded the stoichiometric one, 60 A degrees C, magnetic stirrer, atmospheric pressure. Bentonite was successfully pillared with AlFe and AlFeNi polyoxo cations. The chemical composition of the synthesized samples was: SiO2 56.5, Al2O3 31.3, Fe2O3 9.2; SiO2 56.4, Al2O3 31.9, Fe2O3 8.9 and NiO 0.1; SiO2 61.1, Al2O3 31.3, Fe2O3 4.8 and NiO LT 0.01 for AlFe10-PILC, AlFe10Ni5-PILC and AlFe5Ni5-PILC, respectively. The values of textural property parameters decreased in the following order AlFe10-PILC > AlFe10Ni5-PILC > AlFe5Ni5-PILC. Almost complete decolorization was achieved using all synthesized catalysts and followed first order kinetics. AlFe10Ni5-PILC induced the highest decolorization rate. Somewhat higher decolorization rate in the presence of AlFe10Ni5-PILC in comparison with AlFe5Ni5-PILC can probably be ascribed to one of the following properties or their combined effect: higher Fe content and more developed porous structure. Adsorption of AY99 on AlFe5Ni5-PILC and its degradation by H2O2 (without catalyst) were investigated in order for their influence on the decolorization of AY99, in comparison with that of CWPO using AlFe10Ni5-PILC, to be estimated. The adsorption was the least efficient, followed by degradation using H2O2 (without catalyst). CWPO was more efficient when compared to adsorption and degradation by H2O2 together. CWPO using Al,Fe,Ni-PILC can be regarded as promising method for degradation of azo dyes.

[Resumo:] Os colorantes orgánicos sintéticos son tóxicos, moitos incluso canceríxenos e mutáxenos, e alteran a vida dos ecosistemas acuáticos nos que acaban como resultado da actividade industrial. Entre eles podemos encontrar o azul de metileno. Debido á súa escasa eliminación natural, búscanse métodos eficaces para retiralos das augas. Entre estes métodos está a biosorción que é efectiva, barata e sinxela e onde o uso de microalgas é novidoso e resulta interesante pola súa versatilidade. No presente estudo investigouse o potencial de Chlamydomonas moewusii Gerlof para a biorremediación do colorante azul de metileno dunha solución acuosa. Isto realizouse a través da eficiencia de retirada e da cantidade de colorante adsorbido ao longo do tempo e variando a concentración inicial do contaminante. Ao proceso aplicáronselle as isotermas de adsorción (Langmuir e Freundlich), o factor de separación (RL) e o factor de bioconcentración (FBC). Observouse unha clara redución do azul de metileno na solución como resultado da acción da biomasa da microalga e unha cantidade máxima de adsorción (qm) de 200,88 mg/g segundo o modelo de isoterma de Langmuir, que foi quen mellor describiu os datos no equilibrio. O factor RL mostrou un proceso de sorción favorable ao estar comprendido entre 0 e 1 e o factor de bioconcentración un valor en torno a 1000. Todos estes resultados evidencian a eficacia da biomasa de C. moewusii e demostran o seu potencial uso na retirada de azul de metileno dunha solución acuosa., [Resumen:] Los colorantes orgánicos sintéticos son tóxicos, muchos incluso cancerígenos y mutagénicos, y alteran la vida de los ecosistemas acuáticos en los que acaban como resultado de la actividad industrial. Entre ellos podemos encontrar el azul de metileno. Debido a su escasa eliminación natural, se buscan métodos eficaces para retirarlos de las aguas. Entre estos métodos está la biosorción que es efectiva, barata y sencilla y donde el uso de microalgas es novedoso y resulta interesante por su versatilidad. En el presente estudio se ha investigado el potencial de Chlamydomonas moewusii Gerlof para la biorremediación del colorante azul de metileno de una solución acuosa. Esto se realizó a través de la eficiencia de retirada y de la cantidad de colorante adsorbido a lo largo del tiempo y variando la concentración inicial del contaminante. Al proceso se le aplicaron las isotermas de adsorción (Langmuir y Freundlich), el factor de separación (RL) y el factor de bioconcentración (FBC). Se observó una clara reducción del azul de metileno en la solución como resultado de la acción de la biomasa de la microalga y una cantidad máxima de adsorción (qm) de 200,88 mg/g según el modelo de isoterma de Langmuir, que fue quien mejor describió los datos en el equilibrio. El factor RL mostró un proceso de sorción favorable al estar comprendido entre 0 e 1 y el factor de bioconcentración un valor en torno a 1000. Todos estos resultados evidencian la eficacia de la biomasa de C. moewusii y demuestran su potencial uso en la retirada de azul de metileno de una solución acuosa., [Abstract:] Synthetic organic dyes are toxic, some of them even carcinogenic and mutagenic, and alter acuatic life, where they end up as a result of industrial activity. Into this category we can find methylene blue. Due to their low natural elimination, effective methods to remove them from waters are being tested. One of which is biosorption, an is effective, cheap and simple method where the use of microalgae is a novel and interesting way because of its versatility. In the present work, bioremediation of methylene blue in aqueous solution by Chlamydomonas moewusii Gerlof has been investigated using the sorption efficiency and the amount of dye adsorbed over time and varying the initial concentration of the contaminant. Isotherms (Langmuir and Freundlich), separarion factor (RL) and bioconcentration factor (BCF) were applied on the adsorption process. Methylene blue reduction was observed in the solution as a result of microalgae’s action and the maximum uptake (qm) was 200,88 mg/g according to Langmuir isotherm model, which best described equilibrium data. The RL value showed feasible sorption process as the obtained value was between 0 and 1 and bioconcentration factor value was arround 1000. Results from this study evidenced the efficacy of C. moewusii biomass and demostrate its potential use in methylene blue dye removal from aqueous solution.

Cilj ove doktorske disertacije je da se ispitaju mogućnosti imobilizacije nanočestica titan-dioksida (TiO2) na hidrogelove kao nosače i fotodegradacija boja za tekstil iz vodenih rastvora pomoću titan-dioksid/hidrogel nanokompozita za potrebe prečišćavanja otpadnih voda iz tekstilne industrije. U radu su korišćene dve vrste TiO2 nanočestica: (a) sintetisane koloidne nanočestice TiO2, dobijene kiselom hidrolizom titan-tetrahlorida; (b) komercijalno dostupne nanočestice TiO2 (Degussa P25), radi poređenja fotokatalitičke aktivnosti. Kao nosači nanočestica TiO2 pripremljeni su sledeći hidrogelovi: (a) hidrogelovi hitozana, itakonske kiseline i metakrilne kiseline sintetisani radikalnom polimerizacijom; (b) mikročestice hitozana i poli(metakrilne kiseline), po prvi put sintetisane inverznom suspenzionom polimerizacijom; (c) interpenetrirajuće mreže (IPM) natrijum-alginata i delimično neutralisane poli(metakrilne kiseline) dobijene radikalnom polimerizacijom i naknadnim umrežavanjem jonima kalcijuma. Imobilizacijom nanočestica titan-dioksida na hidrogelove dobijeni su TiO2/hidrogel nanokompoziti, koji su okarakterisani i ispitana je njihova fotokatalitička aktivnost. Prisustvo nanočestica TiO2 na/u hidrogelovima je potvrđeno energetskom disperzionom spektroskopijom (EDX). Skenirajuća elektronska mikroskopija (SEM) je pokazala da hidrogelovi hitozana i interpenetrirajuće mreže natrijum-alginata imaju poroznu strukturu. Eksperimentima bubrenja i reološkim ispitivanjima je potvrđeno da veličina pora, kinetika bubrenja i mehanička jačina zavise od sastava hidrogelova, stepena umreženja, prisustva i vrste imobilisanih nanočestica TiO2. SEM analiza i optička mikroskopija su pokazale da mikročestice hitozana imaju sferičnu strukturu. Infracrvenom spektroskopijom sa Fourier-ovim transformacijama (FTIR) je utvrđeno da su u polimernu mrežu nosača ugrađene sve komponente prisutne tokom sinteze. Termogravimetrijskom analizom (TGA) i skenirajućom kalorimetrijom (DSC) je zaključeno da, The aim of this Ph.D. thesis was to investigate the possibility of immobilization of titanium dioxide (TiO2) nanoparticles onto/into hydrogels as carriers, as well as the photodegradation of textile dyes from aqueous solutions by titanium dioxide/hydrogel nanocomposites that could be exploited for treatment of textile effluents. Two types of TiO2 nanoparticles were used: (a) freshly synthetized colloidal TiO2 nanoparticles, prepared by acid hydrolysis of titanium tetrachloride; (b) commercially available TiO2 nanoparticles (Degussa P25), which were used for comparison of photocatalytic activity. The following hydrogels have been synthetized as a carriers for TiO2 nanoparticles: (a) chitosan, itaconic acid and methacrylic acid hydrogels synthesized by free radical polymerization; (b) chitosan and poly(methacrylic acid) microparticles (Ch/PMA), which were synthesized for the first time by inverse suspension polymerization; (c) sodium alginate and partially neutralized poly(methacrylic acid) interpenetrating polymer networks (IPN) obtained by free radical polymerization followed by additional cross-linking of sodium alginate with calcium ions. TiO2/hydrogel nanocomposites were obtained by immobilization of TiO2 nanoparticles onto/into hydrogels, which were afterwards characterized and their photocatalytic activity was tested. The presence of TiO2 nanoparticles onto/into hydrogels was confirmed by energy dispersive spectroscopy (EDX). The porous structure of the chitosan-based hydrogels and sodium alginate-based interpenetrating networks was observed by SEM analysis. Swelling experiments and rheological studies showed that the pore size, swelling kinetics and mechanical strength depend on the hydrogel composition, degree of crosslinking, presence of TiO2 nanoparticles and the type of immobilized TiO2 nanoparticles. SEM analysis and optical microscopy revealed that chitosan microparticles have a spherical structure. Infrared spectroscopy with Fourier transformation (FTIR

The aim of this Ph.D. thesis was to investigate the possibility of immobilization of titanium dioxide (TiO2) nanoparticles onto/into hydrogels as carriers, as well as the photodegradation of textile dyes from aqueous solutions by titanium dioxide/hydrogel nanocomposites that could be exploited for treatment of textile effluents. Two types of TiO2 nanoparticles were used: (a) freshly synthetized colloidal TiO2 nanoparticles, prepared by acid hydrolysis of titanium tetrachloride; (b) commercially available TiO2 nanoparticles (Degussa P25), which were used for comparison of photocatalytic activity. The following hydrogels have been synthetized as a carriers for TiO2 nanoparticles: (a) chitosan, itaconic acid and methacrylic acid hydrogels synthesized by free radical polymerization; (b) chitosan and poly(methacrylic acid) microparticles (Ch/PMA), which were synthesized for the first time by inverse suspension polymerization; (c) sodium alginate and partially neutralized poly(methacrylic acid) interpenetrating polymer networks (IPN) obtained by free radical polymerization followed by additional cross-linking of sodium alginate with calcium ions. TiO2/hydrogel nanocomposites were obtained by immobilization of TiO2 nanoparticles onto/into hydrogels, which were afterwards characterized and their photocatalytic activity was tested. The presence of TiO2 nanoparticles onto/into hydrogels was confirmed by energy dispersive spectroscopy (EDX). The porous structure of the chitosan-based hydrogels and sodium alginate-based interpenetrating networks was observed by SEM analysis. Swelling experiments and rheological studies showed that the pore size, swelling kinetics and mechanical strength depend on the hydrogel composition, degree of crosslinking, presence of TiO2 nanoparticles and the type of immobilized TiO2 nanoparticles. SEM analysis and optical microscopy revealed that chitosan microparticles have a spherical structure. Infrared spectroscopy with Fourier transformation (FTIR, Cilj ove doktorske disertacije je da se ispitaju mogućnosti imobilizacije nanočestica titan-dioksida (TiO2) na hidrogelove kao nosače i fotodegradacija boja za tekstil iz vodenih rastvora pomoću titan-dioksid/hidrogel nanokompozita za potrebe prečišćavanja otpadnih voda iz tekstilne industrije. U radu su korišćene dve vrste TiO2 nanočestica: (a) sintetisane koloidne nanočestice TiO2, dobijene kiselom hidrolizom titan-tetrahlorida; (b) komercijalno dostupne nanočestice TiO2 (Degussa P25), radi poređenja fotokatalitičke aktivnosti. Kao nosači nanočestica TiO2 pripremljeni su sledeći hidrogelovi: (a) hidrogelovi hitozana, itakonske kiseline i metakrilne kiseline sintetisani radikalnom polimerizacijom; (b) mikročestice hitozana i poli(metakrilne kiseline), po prvi put sintetisane inverznom suspenzionom polimerizacijom; (c) interpenetrirajuće mreže (IPM) natrijum-alginata i delimično neutralisane poli(metakrilne kiseline) dobijene radikalnom polimerizacijom i naknadnim umrežavanjem jonima kalcijuma. Imobilizacijom nanočestica titan-dioksida na hidrogelove dobijeni su TiO2/hidrogel nanokompoziti, koji su okarakterisani i ispitana je njihova fotokatalitička aktivnost. Prisustvo nanočestica TiO2 na/u hidrogelovima je potvrđeno energetskom disperzionom spektroskopijom (EDX). Skenirajuća elektronska mikroskopija (SEM) je pokazala da hidrogelovi hitozana i interpenetrirajuće mreže natrijum-alginata imaju poroznu strukturu. Eksperimentima bubrenja i reološkim ispitivanjima je potvrđeno da veličina pora, kinetika bubrenja i mehanička jačina zavise od sastava hidrogelova, stepena umreženja, prisustva i vrste imobilisanih nanočestica TiO2. SEM analiza i optička mikroskopija su pokazale da mikročestice hitozana imaju sferičnu strukturu. Infracrvenom spektroskopijom sa Fourier-ovim transformacijama (FTIR) je utvrđeno da su u polimernu mrežu nosača ugrađene sve komponente prisutne tokom sinteze. Termogravimetrijskom analizom (TGA) i skenirajućom kalorimetrijom (DSC) je zaključeno da

The aim of this Ph.D. thesis was to investigate the possibility of immobilization of titanium dioxide (TiO2) nanoparticles onto/into hydrogels as carriers, as well as the photodegradation of textile dyes from aqueous solutions by titanium dioxide/hydrogel nanocomposites that could be exploited for treatment of textile effluents. Two types of TiO2 nanoparticles were used: (a) freshly synthetized colloidal TiO2 nanoparticles, prepared by acid hydrolysis of titanium tetrachloride; (b) commercially available TiO2 nanoparticles (Degussa P25), which were used for comparison of photocatalytic activity. The following hydrogels have been synthetized as a carriers for TiO2 nanoparticles: (a) chitosan, itaconic acid and methacrylic acid hydrogels synthesized by free radical polymerization; (b) chitosan and poly(methacrylic acid) microparticles (Ch/PMA), which were synthesized for the first time by inverse suspension polymerization; (c) sodium alginate and partially neutralized poly(methacrylic acid) interpenetrating polymer networks (IPN) obtained by free radical polymerization followed by additional cross-linking of sodium alginate with calcium ions. TiO2/hydrogel nanocomposites were obtained by immobilization of TiO2 nanoparticles onto/into hydrogels, which were afterwards characterized and their photocatalytic activity was tested. The presence of TiO2 nanoparticles onto/into hydrogels was confirmed by energy dispersive spectroscopy (EDX). The porous structure of the chitosan-based hydrogels and sodium alginate-based interpenetrating networks was observed by SEM analysis. Swelling experiments and rheological studies showed that the pore size, swelling kinetics and mechanical strength depend on the hydrogel composition, degree of crosslinking, presence of TiO2 nanoparticles and the type of immobilized TiO2 nanoparticles. SEM analysis and optical microscopy revealed that chitosan microparticles have a spherical structure. Infrared spectroscopy with Fourier transformation (FTIR, Cilj ove doktorske disertacije je da se ispitaju mogućnosti imobilizacije nanočestica titan-dioksida (TiO2) na hidrogelove kao nosače i fotodegradacija boja za tekstil iz vodenih rastvora pomoću titan-dioksid/hidrogel nanokompozita za potrebe prečišćavanja otpadnih voda iz tekstilne industrije. U radu su korišćene dve vrste TiO2 nanočestica: (a) sintetisane koloidne nanočestice TiO2, dobijene kiselom hidrolizom titan-tetrahlorida; (b) komercijalno dostupne nanočestice TiO2 (Degussa P25), radi poređenja fotokatalitičke aktivnosti. Kao nosači nanočestica TiO2 pripremljeni su sledeći hidrogelovi: (a) hidrogelovi hitozana, itakonske kiseline i metakrilne kiseline sintetisani radikalnom polimerizacijom; (b) mikročestice hitozana i poli(metakrilne kiseline), po prvi put sintetisane inverznom suspenzionom polimerizacijom; (c) interpenetrirajuće mreže (IPM) natrijum-alginata i delimično neutralisane poli(metakrilne kiseline) dobijene radikalnom polimerizacijom i naknadnim umrežavanjem jonima kalcijuma. Imobilizacijom nanočestica titan-dioksida na hidrogelove dobijeni su TiO2/hidrogel nanokompoziti, koji su okarakterisani i ispitana je njihova fotokatalitička aktivnost. Prisustvo nanočestica TiO2 na/u hidrogelovima je potvrđeno energetskom disperzionom spektroskopijom (EDX). Skenirajuća elektronska mikroskopija (SEM) je pokazala da hidrogelovi hitozana i interpenetrirajuće mreže natrijum-alginata imaju poroznu strukturu. Eksperimentima bubrenja i reološkim ispitivanjima je potvrđeno da veličina pora, kinetika bubrenja i mehanička jačina zavise od sastava hidrogelova, stepena umreženja, prisustva i vrste imobilisanih nanočestica TiO2. SEM analiza i optička mikroskopija su pokazale da mikročestice hitozana imaju sferičnu strukturu. Infracrvenom spektroskopijom sa Fourier-ovim transformacijama (FTIR) je utvrđeno da su u polimernu mrežu nosača ugrađene sve komponente prisutne tokom sinteze. Termogravimetrijskom analizom (TGA) i skenirajućom kalorimetrijom (DSC) je zaključeno da

Azo dye degradation occurs by means of the oxidation–reduction reactions which have the azo dye acting as final electron acceptor. Some carbon sources can act as electron donors because the products of their metabolism act as redox mediators. In order to enhance the dye biodegradation process, the present study aims to evaluate the decolorization of an artificial wastewater, containing the azo dye Direct Red 75 (DR75), led by a microbial consortium from rice husks, testing the effect in the process of glucose and yeast extract as carbon sources. Samples with and without 0.1 M Sodium phosphate buffer were also analysed. The decolorization was measured by means UV-VIS spectrophotometry. The percentage of decolorization of the samples over the time indicates that the sample with yeast extract, rinse water of rice husks and without buffer presented the best decolorization rate, about 80%. Therefore, the results presented in this study may also suggest that yeast extract is a better carbon source for dye biodegradation than glucose.

Disperse dyes, which are used for colouring synthetic textile fibres, are well-known contact sensitisers. To investigate the outcome of patch-testing with a textile dye mix (TDM) at 7 dermatology clinics in Sweden, a TDM tested at 2 concentrations was included into the baseline series during one year. The mix consisted of Disperse (D) Blue 35, D Yellow 3, D Orange 1 and 3, D Red 1 and 17, all 1.0%, and D Blue 106 and D Blue 124, each 0.3% in the mix 6.6% and 1.0% each in the mix 8.0%. In 2,122 tested patients, contact allergy to the TDM at the concentration 8.0% was found in 2.8% and to the TDM at 6.6% in 2.5% of the patients. The contact allergy to the TDM could explain or contribute to the dermatitis in about 35% of the patients. Conclusion: contact allergy to the TDM is common and inclusion into the Swedish baseline series should be considered.

The degradation and decolorization of azo dye COLRON RED SD3B as model pollutant by H2O2/ UV and H2O2/Fe2+/UV processes were investigated. The effects of dye concentration, solution pH, and Fe2+ and H2O2 dosages were studied using Taguchi´s experimental design method. Photo-Fenton process showed to be more efficient than H2O2/UV process for the color removal and degradation of the dye. The conditions that produced higher degradations rates were pH=2, dye concentration of 100 ppm, ferrous dosage of 80 ppm and hydrogen peroxide dosage of 102 ppm (3.0 mmol/L). Under these conditions, 65.5 % COD reduction and 77.0 % decolorization of the azo dye wastewater were achieved after one hour of treatment., En la presente investigación se estudió la efectividad de los procesos de oxidación avanzada H2O2/UV y H2O2/Fe2+/UV en la degradación y decoloración de agua contaminada con colorante textil COLRON RED SD3B, a manera de contaminante modelo. Para ello se analizó el efecto de la concentración inicial del colorante, el pH de la solución, la concentración de hierro y la concentración de peróxido de hidrógeno mediante un diseño estadístico de experimentos de Taguchi. Del estudio se concluyó que el proceso Foto-Fenton (H2O2/Fe2+/UV) genera resultados más favorables en la degradación y decoloración del tinte, en las siguientes condiciones de operación: pH= 2, concentraciones de colorante de 100 ppm, de hierro de 80 ppm y de peróxido de hidrógeno de 102 ppm (3,0 mmol/L). Bajo estas condiciones se obtuvieron porcentajes de reducción promedio de 65,5% en la DQO y de 77,0% en la decoloración del tinte luego de una hora de tratamiento.

The degradation and decolorization of azo dye COLRON RED SD3B as model pollutant by H2O2/ UV and H2O2/Fe2+/UV processes were investigated. The effects of dye concentration, solution pH, and Fe2+ and H2O2 dosages were studied using Taguchi´s experimental design method. Photo-Fenton process showed to be more efficient than H2O2/UV process for the color removal and degradation of the dye. The conditions that produced higher degradations rates were pH=2, dye concentration of 100 ppm, ferrous dosage of 80 ppm and hydrogen peroxide dosage of 102 ppm (3.0 mmol/L). Under these conditions, 65.5 % COD reduction and 77.0 % decolorization of the azo dye wastewater were achieved after one hour of treatment., En la presente investigación se estudió la efectividad de los procesos de oxidación avanzada H2O2/UV y H2O2/Fe2+/UV en la degradación y decoloración de agua contaminada con colorante textil COLRON RED SD3B, a manera de contaminante modelo. Para ello se analizó el efecto de la concentración inicial del colorante, el pH de la solución, la concentración de hierro y la concentración de peróxido de hidrógeno mediante un diseño estadístico de experimentos de Taguchi. Del estudio se concluyó que el proceso Foto-Fenton (H2O2/Fe2+/UV) genera resultados más favorables en la degradación y decoloración del tinte, en las siguientes condiciones de operación: pH= 2, concentraciones de colorante de 100 ppm, de hierro de 80 ppm y de peróxido de hidrógeno de 102 ppm (3,0 mmol/L). Bajo estas condiciones se obtuvieron porcentajes de reducción promedio de 65,5% en la DQO y de 77,0% en la decoloración del tinte luego de una hora de tratamiento.

The degradation and decolorization of azo dye COLRON RED SD3B as model pollutant by H2O2/ UV and H2O2/Fe2+/UV processes were investigated. The effects of dye concentration, solution pH, and Fe2+ and H2O2 dosages were studied using Taguchi´s experimental design method. Photo-Fenton process showed to be more efficient than H2O2/UV process for the color removal and degradation of the dye. The conditions that produced higher degradations rates were pH=2, dye concentration of 100 ppm, ferrous dosage of 80 ppm and hydrogen peroxide dosage of 102 ppm (3.0 mmol/L). Under these conditions, 65.5 % COD reduction and 77.0 % decolorization of the azo dye wastewater were achieved after one hour of treatment., En la presente investigación se estudió la efectividad de los procesos de oxidación avanzada H2O2/UV y H2O2/Fe2+/UV en la degradación y decoloración de agua contaminada con colorante textil COLRON RED SD3B, a manera de contaminante modelo. Para ello se analizó el efecto de la concentración inicial del colorante, el pH de la solución, la concentración de hierro y la concentración de peróxido de hidrógeno mediante un diseño estadístico de experimentos de Taguchi. Del estudio se concluyó que el proceso Foto-Fenton (H2O2/Fe2+/UV) genera resultados más favorables en la degradación y decoloración del tinte, en las siguientes condiciones de operación: pH= 2, concentraciones de colorante de 100 ppm, de hierro de 80 ppm y de peróxido de hidrógeno de 102 ppm (3,0 mmol/L). Bajo estas condiciones se obtuvieron porcentajes de reducción promedio de 65,5% en la DQO y de 77,0% en la decoloración del tinte luego de una hora de tratamiento.

The degradation and decolorization of azo dye COLRON RED SD3B as model pollutant by H2O2/ UV and H2O2/Fe2+/UV processes were investigated. The effects of dye concentration, solution pH, and Fe2+ and H2O2 dosages were studied using Taguchi´s experimental design method. Photo-Fenton process showed to be more efficient than H2O2/UV process for the color removal and degradation of the dye. The conditions that produced higher degradations rates were pH=2, dye concentration of 100 ppm, ferrous dosage of 80 ppm and hydrogen peroxide dosage of 102 ppm (3.0 mmol/L). Under these conditions, 65.5 % COD reduction and 77.0 % decolorization of the azo dye wastewater were achieved after one hour of treatment., En la presente investigación se estudió la efectividad de los procesos de oxidación avanzada H2O2/UV y H2O2/Fe2+/UV en la degradación y decoloración de agua contaminada con colorante textil COLRON RED SD3B, a manera de contaminante modelo. Para ello se analizó el efecto de la concentración inicial del colorante, el pH de la solución, la concentración de hierro y la concentración de peróxido de hidrógeno mediante un diseño estadístico de experimentos de Taguchi. Del estudio se concluyó que el proceso Foto-Fenton (H2O2/Fe2+/UV) genera resultados más favorables en la degradación y decoloración del tinte, en las siguientes condiciones de operación: pH= 2, concentraciones de colorante de 100 ppm, de hierro de 80 ppm y de peróxido de hidrógeno de 102 ppm (3,0 mmol/L). Bajo estas condiciones se obtuvieron porcentajes de reducción promedio de 65,5% en la DQO y de 77,0% en la decoloración del tinte luego de una hora de tratamiento.

The degradation and decolorization of azo dye COLRON RED SD3B as model pollutant by H2O2/ UV and H2O2/Fe2+/UV processes were investigated. The effects of dye concentration, solution pH, and Fe2+ and H2O2 dosages were studied using Taguchi´s experimental design method. Photo-Fenton process showed to be more efficient than H2O2/UV process for the color removal and degradation of the dye. The conditions that produced higher degradations rates were pH=2, dye concentration of 100 ppm, ferrous dosage of 80 ppm and hydrogen peroxide dosage of 102 ppm (3.0 mmol/L). Under these conditions, 65.5 % COD reduction and 77.0 % decolorization of the azo dye wastewater were achieved after one hour of treatment., En la presente investigación se estudió la efectividad de los procesos de oxidación avanzada H2O2/UV y H2O2/Fe2+/UV en la degradación y decoloración de agua contaminada con colorante textil COLRON RED SD3B, a manera de contaminante modelo. Para ello se analizó el efecto de la concentración inicial del colorante, el pH de la solución, la concentración de hierro y la concentración de peróxido de hidrógeno mediante un diseño estadístico de experimentos de Taguchi. Del estudio se concluyó que el proceso Foto-Fenton (H2O2/Fe2+/UV) genera resultados más favorables en la degradación y decoloración del tinte, en las siguientes condiciones de operación: pH= 2, concentraciones de colorante de 100 ppm, de hierro de 80 ppm y de peróxido de hidrógeno de 102 ppm (3,0 mmol/L). Bajo estas condiciones se obtuvieron porcentajes de reducción promedio de 65,5% en la DQO y de 77,0% en la decoloración del tinte luego de una hora de tratamiento.

The degradation and decolorization of azo dye COLRON RED SD3B as model pollutant by H2O2/ UV and H2O2/Fe2+/UV processes were investigated. The effects of dye concentration, solution pH, and Fe2+ and H2O2 dosages were studied using Taguchi´s experimental design method. Photo-Fenton process showed to be more efficient than H2O2/UV process for the color removal and degradation of the dye. The conditions that produced higher degradations rates were pH=2, dye concentration of 100 ppm, ferrous dosage of 80 ppm and hydrogen peroxide dosage of 102 ppm (3.0 mmol/L). Under these conditions, 65.5 % COD reduction and 77.0 % decolorization of the azo dye wastewater were achieved after one hour of treatment., En la presente investigación se estudió la efectividad de los procesos de oxidación avanzada H2O2/UV y H2O2/Fe2+/UV en la degradación y decoloración de agua contaminada con colorante textil COLRON RED SD3B, a manera de contaminante modelo. Para ello se analizó el efecto de la concentración inicial del colorante, el pH de la solución, la concentración de hierro y la concentración de peróxido de hidrógeno mediante un diseño estadístico de experimentos de Taguchi. Del estudio se concluyó que el proceso Foto-Fenton (H2O2/Fe2+/UV) genera resultados más favorables en la degradación y decoloración del tinte, en las siguientes condiciones de operación: pH= 2, concentraciones de colorante de 100 ppm, de hierro de 80 ppm y de peróxido de hidrógeno de 102 ppm (3,0 mmol/L). Bajo estas condiciones se obtuvieron porcentajes de reducción promedio de 65,5% en la DQO y de 77,0% en la decoloración del tinte luego de una hora de tratamiento.

Background: Textile dyes are hardly removed from effluents by conventional wastewater treatment but can be degraded by a number of physicochemical processes nevertheless having specific limitations. The development of bioremediation processes may provide a viable alternative. Results: Resting cells of three aquatic fungal strains, Alternaria sp. (Tt-S1), Coniothyrium sp. (Kl-S5) and Phoma sp. (DSM22425), were evaluated for their ability to decolorize model effluents of different dye application classes. Phoma sp., who decolorized all four applied model wastewaters (MWW), was immobilized on a polyester-based fleece material originally designed for the use as cooker-hood filters, and applied in internal loop airlift and bubble column reactors in repeated batch mode under sterile and nonsterile conditions. Depending on the applied MWW and bioreactor setup, a decolorization by more than 90 % was achieved in three consecutive treatment cycles and a total operation time of 16 days. In an upscaled reactor (10 L), Phoma sp. decolorized a MWW for acid dyes by 61 %. Chemical oxygen demand of the MWW was reduced by 36 %. Conclusion: The presented results underline the potential of aquatic fungi for the development of textile dyeing effluent treatment processes.

Background: Textile dyes are hardly removed from effluents by conventional wastewater treatment but can be degraded by a number of physicochemical processes nevertheless having specific limitations. The development of bioremediation processes may provide a viable alternative. Results: Resting cells of three aquatic fungal strains, Alternaria sp. (Tt-S1), Coniothyrium sp. (Kl-S5) and Phoma sp. (DSM22425), were evaluated for their ability to decolorize model effluents of different dye application classes. Phoma sp., who decolorized all four applied model wastewaters (MWW), was immobilized on a polyester-based fleece material originally designed for the use as cooker-hood filters, and applied in internal loop airlift and bubble column reactors in repeated batch mode under sterile and nonsterile conditions. Depending on the applied MWW and bioreactor setup, a decolorization by more than 90 % was achieved in three consecutive treatment cycles and a total operation time of 16 days. In an upscaled reactor (10 L), Phoma sp. decolorized a MWW for acid dyes by 61 %. Chemical oxygen demand of the MWW was reduced by 36 %. Conclusion: The presented results underline the potential of aquatic fungi for the development of textile dyeing effluent treatment processes.

BACKGROUND: Textile dyes are hardly removed from effluents by conventional wastewater treatment but can be degraded by a number of physicochemical processes, which nevertheless have specific limitations. The development of bioremediation processes may provide a viable alternative. RESULTS: Resting cells of three aquatic fungal strains, Alternaria sp. (Tt-S1), Coniothyrium sp. (Kl-S5) and Phoma sp. (DSM22425), were evaluated for their ability to decolorize model effluents of different dye application classes. Phoma sp., which decolorized all four applied model wastewaters (MWW), was immobilized on a polyester-based fleece material originally designed for use as cooker-hood filters, and applied in internal loop airlift and bubble column reactors in repeated batch mode under sterile and non-sterile conditions. Depending on the applied MWW and bioreactor setup, a decolorization of more than 90% was achieved in three consecutive treatment cycles and total operating time of 16 days. In an upscaled reactor (10 L), Phoma sp. decolorized MWW containing acid dyes by 61%. Chemical oxygen demand of the MWW was reduced by 36%. CONCLUSION: The results presented underline the potential of aquatic fungi for the development of textile dyeing effluent treatment processes.

The purpose is to develop a complete microbiological model system for the treatment of wastewater from textile mills in developing countries. Arti fi cial wastewater was treated by microorganisms growing on wood shavings from Norway spruce during unsterile conditions. The microorganisms were inoculated from forest residues. Mixtures of the azo dyes Reactive Black 5 and Reactive Red 2 were degraded in batch as well as continuous experiments. Reactive Red 2 mixed with the anthraquinone dye Reactive Blue 4 was also treated in the continuous system. The system consisted of three reservoirs e the fi rst two with an anaerobic environment and the third with an aerobic. The dye concentrations were 200 mg l 1 of each dye in the continuous system and the retention time was approximately 4 days and 20 h per reservoir. Samples from the process were analysed with spectrophotometer and LC/MS to monitor the degradation process. 86-90% of the colour was removed after a treatment of 4 days and 23 h in the continuous process. Two metabolites were found in the outlets of reactors one and two, but they were degraded to below the detection limit in the aerobic reactor.

Studies were carried out on the decolourization of textile azo dye using newly isolated aerobic bacterial culture. Among the 58 strains of aerobic bacteria isolated from soil contaminated with textile industry (Shivalik polymer Ltd. Faridabad) effluent, three showed remarkable ability in decolourizing the widely utilized azo dye (Congo Red). These strains also readily grew in and decolourized the high concentrations of dye (100 mgL -1). The aerobic bacterial isolate SPR42, was able to decolourize the Congo Red dye at a concentration of 100 mgL -1 upto 94% within 24 hrs at static conditions. The temperature and pH for optimum growth and activity of the isolate were reported as 37 oC and 8.5, respectively. The colorless bacterial biomass after decolourization suggested that decolourization was due to biodegradation, rather than inactive surface adsorption. Phenotypic characterization and phylogenetic analysis based on 16S rDNA sequence comparisons indicate that the strain SPR42 identified as Bacillus subtilis. This isolate can be a potential strain for biological treatment of effluents of TPI (Textile Processing Industry).

The photodegradation of C.I. Reactive Orange 16 (RO16), commonly used as a textile dye, was investigated using TiO2 as a catalyst and the sun lamp. The experiments showed that TiO2 and simulated solar light are necessary for the effective photodegradation, although a low degradation/adsorption was observed when only the simulated solar light or TiO2 was used. The effect of some parameters such as the initial concentration of the catalyst, the initial dye concentration, the initial Na2CO2 and NaCl concentrations, pH, and the presence of H2O2 on photodegradation of RO16 was examined. The photodegradation efficiency was highest at the catalyst concentration of 2.0 g/l. The degradation was faster in the acidic than in alkaline pH range. High adsorption of the dye was observed at low pH, while at high pH almost no adsorption was detected. A lower concentration of Na2CO2 decreased the photodegradation of RO16, while a higher concentration increased the photodegradation. The presence of NaCI led to the inhibition of the photodegradation process. The low concentration of H2P2 increased the RO16 photodegradation efficiency, while at higher concentration of H2O2 inhibition was observed.

CI Basic Yellow 28 (BY28), commonly used as a textile dye, could be photocatalytically degraded using TiO2 as catalyst and irradiated by UV-A lamp (300 W). However, UV and TiO2 showed no effect on the photodegradation when they were used separately. The effect of some parameters such as initial concentration of catalyst, initial dye concentration, initial NaCl and Na2CO3 concentration, pH and presence of H2O2 on degradation rate of BY28 was examined.

CI Basic Yellow 28 (BY28), commonly used as a textile dye, could be photocatalytically degraded using TiO2 as catalyst and irradiated by UV-A lamp (300 W). However, UV and TiO2 showed no effect on the photodegradation when they were used separately. The effect of some parameters such as initial concentration of catalyst, initial dye concentration, initial NaCl and Na2CO3 concentration, pH and presence of H2O2 on degradation rate of BY28 was examined.

The photodegradation of C.I. Reactive Orange 16 (RO16), commonly used as a textile dye, was investigated using TiO2 as a catalyst and the sun lamp. The experiments showed that TiO2 and simulated solar light are necessary for the effective photodegradation, although a low degradation/adsorption was observed when only the simulated solar light or TiO2 was used. The effect of some parameters such as the initial concentration of the catalyst, the initial dye concentration, the initial Na2CO2 and NaCl concentrations, pH, and the presence of H2O2 on photodegradation of RO16 was examined. The photodegradation efficiency was highest at the catalyst concentration of 2.0 g/l. The degradation was faster in the acidic than in alkaline pH range. High adsorption of the dye was observed at low pH, while at high pH almost no adsorption was detected. A lower concentration of Na2CO2 decreased the photodegradation of RO16, while a higher concentration increased the photodegradation. The presence of NaCI led to the inhibition of the photodegradation process. The low concentration of H2P2 increased the RO16 photodegradation efficiency, while at higher concentration of H2O2 inhibition was observed.

Bioremediation  based  on  microbial  technologies  has  been  extensively  used  for  treating  coloured textile wastewater. In this research, the  potential application of the indigenous and exogenous bacterial cultures, found as biofilm were investigated for colour removal.  Initial study in the  treatment of the textile  wastewater showed that the mechanism involved in decolourisation was degradation, which was carried out via molecular technique involving amplification of the DNA sequence responsible for decolourisation using pure dye; Orange. In laboratory scale experiment, the  bacteria were  grown as  mixed culture  in suspension  and biofilm using shake flasks technique. Their abilities to decolourise textile wastewater were studied under semianaerobic conditions. Generally, bacteria in the form of biofilms were found to remove colour at faster  rates compared  to that  of suspended cells. Evidence of biofilm formation during decolourisation of textile wastewater was also examined using SEM.

The biodegradation of Grey Lanaset G, which consists of a mixture of metal complexed dye, was studied. Experiments were carried out in a bioreactor with retained pellets of the fungus Trametes versicolor that was operated under conditions of laccase production. Although decolorization was highly efficient (90%), no direct relationship to extracellular enzyme was apparent. Moreover, the extracellular enzyme was found to be unable to degrade the dye in vitro. The process involves several steps. Thus, the initial adsorption of the dye and its transfer into cells is followed by breaking of the metal complex bond in the cells release of the components. The metal (Cr and Co) contents of the biomass and treated solutions, and their closer relationship to intracellular enzyme and degradation of the dye, confirm the initial hypothesis.