Highest Decolorization Rate Research Articles

Investigation of Some Parameters Affecting Methyl OrangeRemoval by Fusarium acuminatum

ABSTRACT Dye stuff released to the ecosystem from textile industries cause a serious contamination and become a major environmental problem over the last few decades. As biological decolorization of textile wastewater is an important issue, Fusarium . acuminatum was used to removal of a frequently used textile dye, methyl orange. Live pellet of Fusarium acuminatum was used and decolorization studies performed in various temperatures and pH conditions with different dye concentrations. The highest decolorization rate was observed at 35ᴼC. 60 mg/L was found as the optimum initial dye concentration. In the pH range of 3-4, decolorization rate was approximately 70%. It was seen that Fusarium acuminatum have the great ability of the methyl orange removal. To our knowledge, it took place for the first time in the literature.

Multiple Applications of Enzymes Induced by Algal Biomasses from a New Bacillus Isolate to Saccharify Algae and Degrade Chemical Dyes

To find a multifunctional lignocellulolytic enzyme-producing strain, ten bacterial isolates from paper mill wastewater were tested for their carboxymethyl cellulose (CMC) hydrolytic ability. Bacillus sp. TPF-1, which exhibits the highest hydrolytic ability, was selected to produce lignocellulolytic enzymes using various biomass types as carbon sources. The highest CMCase (9.12 U/mL) and xylanase (102.55 U/mL) activities were obtained by green algae, and the maximum laccase activity (7037.28 U/L) was induced by Sargassum fusiforme. CMCase and xylanase showed the highest activities at 55 and 50 °C, respectively, with the same optimum pH of 5.4. The laccase exhibited optimum temperature of 40 °C and retained 60% more activity at 80 °C in extreme acid conditions (pH 2.2). To explore the multiple applications of these enzymes, crude enzymes induced by green algae were used to saccharify untreated algae. The reducing sugar produced by crude enzymes and commercial cellulase was 23 and 14% higher than that of the control, respectively, and it was 48% higher using crude enzymes with commercial cellulase (72 h). Additionally, the laccase induced by S. fusiforme was tested to decolorize two chemical dyes under an acidic condition (pH 2.2). The highest decolorization rates were 56.13 and 62.14% for Coomassie brilliant blue R-250 and Congo Red, respectively, in the presence of hydroxybenzotriazole monohydrate.

Study on the optimization of the decolorization of orange essential oil.

The effects of diatomite, activated clay and acticarbon on the decolorization of orange essential oil were investigated. Single factor and orthogonal tests were performed to determine the optimum discoloring conditions. The results showed that the activated clay exhibited the most satisfactory effect on discoloring. Then it was used as the decolorizer for the decolorization of orange essential oil. The highest decolorization rate (84.5%) was obtained using 10% activated clay at 60°C for 30min. The contents of oxygenated compounds (linalool and citral) increased from 1.4 to 3.1% after decolorization. Sensory assessment revealed that the orange essential oil after decolorization using activated clay had a mellow and characteristic orange aroma. Chromaticity analysis showed that it had excellent transparency and yellow color under the optimized condition. Thus, decolorization with activated clay could maintain the quality and prolong the storage of orange essential oil.

Al,Fe,Ni-pillared bentonite in the catalytic wet peroxide oxidation of the textile dye Acid Yellow 99

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 °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 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.

Optimization of environmental parameters on the decolorization of Reactive Brilliant Blue dye by yeast isolates from textile effluent

The present study was conducted to investigate the decolorization and degradation of Reactive Brilliant Blue dye using yeasts isolated from the effluent treatment of the textile industries and the identified yeast strains under optimal conditions using the standard methods. Among twenty-four yeast strains, only five yeasts have the ability to decolorize the dye (2.8%). Three yeast strains; Rhodotorula glutinis, Candida utilis(1) and Candida sphaerica as well as the local two yeast isolates which were identified as Rhodotorula rubra and Cryptococcus albidus showing high decolorization rate, they were used for the decolorization of Reactive Brilliant Blue dye in a medium containing glucose and yeast extract as a best carbon and nitrogen sources, the pH of medium varied among the yeasts, C. utilis(1), R. rubra and C. albidus was 4, while C. sphaerica and R. glutinis was 6 and5.5, respectively. All yeast strains were incubated for 18 h at 25˚C except C. utilis(1) at 37˚C. C. utilis(1), R. glutinis and C. sphaerica showed high decolorization rate under static aerobic conditions. While R. rubra and C. albidus showed decolorization under static anaerobic conditions. According to the potentiality of yeast strains; C. sphaerica could achieved a removal ratio of 68.83%, while C. albidus 68.40%, R. rubra 67.75%, R. glutinis 66.88% and C. utilis(1) 63.85% of Reactive Brilliant Blue dye in a concentration of 10 mg/L. The highest biodegradation of the dye by the five yeast strains was confirmed by using plain distilled water as a decolorization medium. In conclusion, yeast strains could be used for the biodegradation of dye- polluted waters including rate of degradation of anthraquinone dye.

Highly active and thermo-stable anatase TiO2 photocatalysts synthesized by a microwave-assisted hydrothermal method

Phase-pure anatase titanium dioxide (A-TiO2) with high thermal stability is synthesized by a microwave-assisted hydrothermal (MAH) method. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption isotherms, and photoluminescence spectra (PL) analysis. The photo-electrochemical responses are examined via linear sweep voltammetry (LSV), intensity-modulated photocurrent spectroscopy (IMPS), and intensity-modulated photovoltage spectroscopy (IMVS). The photocatalytic activity of TiO2 nanoparticles (NPs) has been confirmed through the methylene blue (MB) de-colorization under the simulated sunlight. The results show that the as-prepared TiO2 nanocrystals possess thermal stability for the anatase-to-rutile phase transformation up to 900 °C. The phase-pure A-TiO2 annealed at 800 °C exhibits a much higher de-colorization rate than the commercially available TiO2 (Degussa P25) powders. The higher photocatalytic activity of this sample is due to its enhanced crystallinity, leading to a lower rate of electron/hole pair recombination and a larger photocurrent density in comparison with all other samples and P25. The sample annealed at 900 °C shows the highest specific activity on MB de-colorization, demonstrating the importance of thermal stability and crystalline phase.

Electricity production from Azo dye wastewater using a microbial fuel cell coupled constructed wetland operating under different operating conditions

Microbial fuel cells (MFCs) have got tremendous attention for their capability to enhance the degradation of some recalcitrant pollutants and simultaneous electricity production. A microbial fuel cell coupled constructed wetland (CW-MFC) is a new device to treat the wastewater and produce energy which has more wastewater treatment volume and more easily to maintenance than others MFCs. The studies on the performance of CW-MFCs are necessary. In this work, the effects of hydraulic residence time (HRT), reactive brilliant red X-3B (ABRX3) proportion and COD concentration on the electricity production of CW-MFC and the degradation characteristics of ABRX3 were investigated. The decolorization rate and the electricity production increased to a peak before slowing down with the elongation of HRT. The highest decolorization rate and electricity production were obtained when HRT was 3 days. The ABRX3 proportion (calculated as COD) in the wastewater played an important role in decolorization and electricity production, which may influence the distribution of electrons in the system. The power density of CW-MFC and the decolorization rate decreased concomitantly with an increasing ABRX3 proportion. The COD concentration influenced the CW-MFC performance slightly. The highest decolorization rate and power density reached 95.6% and 0.852W/m3, respectively, when the COD concentration was 300mg/L while the ABRX3 proportion was 30%. The coulombic efficiency of the CW-MFC depended on glucose and ABRX3 proportions in the wastewater. ABRX3 acquired more electrons than the anode. Further investigations are needed to optimize CW-MFC performance and explain the mechanism of biorefractory compounds degradation and electron motion in CW-MFCs.

The Effect of KNO<sub>3</sub> on Electrolysis-Assisted Flocculation of Azophloxine Using Polyaluminum Chloride

Electrolysis-assisted flocculation methods were used in decoloration of azophloxine. Electrolysis-assisted flocculation of azophloxine was conducted under the applied potential using titanium anode. The concentration of KNO3, flocculating time and applied potential were investigated. The application of applied potential has nearly no power to remove the dye from wastewater since the highest decoloration rate is only 2.5% after treatment at KNO3 concentration of 0.6 mol/L. The total flocculating decoloration efficiency decreases gradually after increasing the KNO3 concentration in the solution. When the applied potential is 7 V, the maximum electrolysis-assisted flocculating decoloration rate is 52.3%. When the electrolysis-assisted flocculating time is 5 min, the maximum decoloration rate is 54.2%.

Adsorptive removal of acid orange 7 from aqueous solution with metal–organic framework material, iron (III) trimesate

In this paper, a highly porous metal–organic framework (MOF) based on iron (III) trimesate (MIL-100 (Fe)) was applied to the adsorption of a harmful anionic dye, acid orange 7 (AO7), from aqueous solution. The influences of various factors on the adsorption as well as adsorption kinetics and isotherms were investigated. It was found that a relatively low pH value was favorable for the adsorption. The high dosage of the adsorbent led to a high decolorization rate, but a low adsorption quantity. The adsorption kinetics obeyed the pseudo-second-order kinetic model and the adsorption isotherms followed the Langmuir mode. The driving force of the adsorption was an entropy effect rather than an enthalpy change. The adsorption mechanism may be explained with a simple electrostatic interaction between AO7 aqueous solution and the adsorbent. The adsorption capacities of MIL-100 (Fe) are much higher than those of an activated carbon. Finally, it can be suggested that (MOFs) having high porosity and large pore size can be potential adsorbents to remove harmful AO7 in contaminated water.

Visible-Light-Induced Degradation of Rhodamine B by Wool-Fe Catalyst

The wool fiber was applied for the support to immobilize ferric ion at room temperature, and the wool-Fe complexes obtained were used as heterogeneous Fenton catalyst for the degradation of Rhodamine B under visible light irradiation. Some factors affecting the degradation of dyes such as ferric ion concentration, catalyst dosage and pH values were investigated. In addition, the photo catalytic degradation of dyes was examined by UV-Vis spectra. The results indicated that increasing ferric ion concentration and catalyst dosage in solution led to the higher decoloration rate of dyes with pH≤6.0. The wool-Fe catalyst exhibits an obvious absorption in the visible region and could effectively degrade Rhodamine B in the presence of H2O2under visible light irradiation.

Controlled synthesis of T-shaped BiVO4 and enhanced visible light responsive photocatalytic activity

A novel T-shaped BiVO4 microcrystal photocatalyst was successfully synthesized by the hydrothermal method with the aid of a structure-directing surfactant SDBS in the present study. Having received well characterization with the aid of various techniques and the results showed that the SDBS greatly changed the microstructure of BiVO4, which had a unique T shape and belonged to the monoclinic family. The fast exchange dynamics between the surfactants bound to the Bi3+ seed surface and the free VO3− in the solution significantly increase the rate of heterogeneous nucleation. In addition, the photocatalytic activity of the prepared T-shaped BiVO4 was evaluated by the degradation of Methylene Blue solution under visible light irradiation, 17% and 47% higher decolorization rates than the commercial P25 and BiVO4 synthesized without SDBS, respectively. Meanwhile, it has been found that the degradation kinetics of MB fitted the pseudo-first-order kinetics and the T-shaped BiVO4 also displayed high photocatalytic performance for metronidazole degradation.

Characterization of yellow bacterial laccase SmLac/role of redox mediators in azo dye decolorization

AbstractBACKGROUNDThe bacterial Stenotrophomonas maltophilia AAP56 laccase (SmLac) has been purified from cell extracts and its spectral and kinetic properties studied. It shows a high decolorization rate (99%) of the diazoic dye Reactive Black 5 (RB5) in the presence of redox mediators such as ABTS (2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid), ASGN (Acetosyringone), SGA (Syringaldehyde) and HOBT (1‐Hydroxy‐Benzotriazole). The optimal pH has been determined as neutral or basic compatible with textile wastewater pH for further treatment application.RESULTSThis paper reports the characterization of the catalytic center of purified SmLac as not a classic blue laccase but a yellow one. Its redox potential has been determined at 638 mV, which indicates that the enzyme is a versatile laccase able to oxidase a wide range of substrates. Performance of the enzyme as catalyst for RB5 decolorization in association with a redox mediator has been demonstrated to be a promising bioremediation process since it presents high degradation ability (almost 99% in 1 h reaction time). The study also demonstrated, by electrochemical studies of redox potential of both mediators/protein and following the driving electron force, the importance of the choice of redox mediator and the limiting step in the laccase mediated reaction in azo dye decolorization.CONCLUSIONIt was demonstrated that the bacterial laccase SmLac has great potential for biotechnological applications (such as azo dye decolorization) compared with Trametes versicolor laccase. © 2013 Society of Chemical Industry

Sequential desilication–isomorphous substitution route to prepare mesostructured silica nanoparticles loaded with ZnO and their photocatalytic activity

A simple electrochemical method followed by impregnation was employed to prepare a coral-like zinc oxide catalyst loaded on mesostructured silica nanoparticles (ZnO/MSN). The introduction of zinc species onto a silica framework was found to form an interaction between the host and support material. XRD analysis suggested the presence of zinc on the internal pore walls of MSN. FE-SEM and TEM analyses displayed nanorods, nanoparticles and coral-like shapes of ZnO, MSN and ZnO/MSN, respectively. 29Si NMR and FTIR results showed that desilication occurred in the silica framework of the MSN accompanied by isomorphous substitution of Zn2+ cations to form an active species Zn–O–Si bond. The photocatalytic activity of the ZnO/MSN was tested by decolorizing methyl orange (MO). It was found that increasing the ZnO loading led to a higher recombination rate of photoinduced electron–hole pairs, which resulted in decreased photocatalytic activity. The highest decolorization rate was obtained using 1gL−1 of 5wt% ZnO/MSN with an optimum dosage of 3.06×10−2mM MO after 8h contact time at pH 2 under UV irradiation. A kinetic study demonstrated that the photocatalytic reaction followed the pseudo first-order model. The photocatalyst was still stable after five cycling runs with a small amount of Zn was leached (<3.0%).

Effect of Specific Active Chlorine Species and Temperature on the Electrochemical Degradation of the Reactive Blue 19 Dye Using a Boron-Doped Diamond or DSA Anode in a Flow Reactor

Galvanostatic electrolyses were carried out to investigate the effect of specific active chlorine species (Cl2, HClO, or ClO–) and temperature on the degradation of reactive blue 19 dye (RB-19) solutions (500 mg L–1 in 0.1 mol L–1 Na2SO4), in the presence or absence of chloride ions, using two anodes of markedly different oxidation power: dimensionally stable anode (DSA — Ti/TiO2RuO2) or boron-doped diamond (Nb/BDD). In the absence of chloride ions in solution (at pH 6.0 and 25 °C), the Nb/BDD anode, due to its higher oxidation power, was notably more effective in decolorizing the RB-19 dye than the DSA anode. Yet, when this decolorization was carried out by chloride-mediated electrooxidation (2 g L–1 NaCl added to the dye solution), both anodes presented significantly enhanced performances, but now greater decolorization rates were attained with the DSA anode, especially at pH 1.0, when Cl2 is the predominant active chlorine species in solution; actually, the highest decolorization rates are attained at 10 °C, when the Cl2 solubility in solution increases. Clearly, Cl2 is the active chlorine species that most readily oxidizes the anthraquinone chromophore center of the RB-19 molecule. The rate of chloride-mediated COD abatement of the RB-19 dye solution was also analyzed (at pH 6.0 and 25 °C); now the oxidation power of the anode is again paramount and Nb/BDD presents a significantly superior performance, because hydroxyl radicals play a crucial role in the oxidation of organics, beyond that possible for the active chlorine species.

Optimization of Environmental Parameters on Microbial Degradation of Reactive Black Dye

The study involved isolation of bacteria possessing high potential to degrade Reactive Black azo dye in liquid medium. Eighty four strains of bacteria were isolated through enrichment technique by using Reactive Black azo dye as the source of carbon and nitrogen in the mineral salt medium. Bacterial strains showing high decolorization rate were used to optimize the decolorization of Reactive Black azo dye in liquid culture. The optimum conditions determined for the four selected bacterial strains for decolorization of Reactive Black (250 mg L-1) were pH 7.0, temperature 32°C, when dye solution was supplemented with 0.5% yeast extract as a co-substrate. Out of these five strains, two strains ETL-1 (Klebsiella oxytoca) and ETL-2 (Bacillus subtillis) showed an excellent potential to decolorize 500 mg L-1 Reactive Black in 6 h in the liquid broth.

Ligninolytic Oxidative System of Fungal Egyptian Isolates and their Applications in the Decolorization of Industrial Dyes

ABSTRACTThe aim of this study was to investigate the ligninolytic system of fungal strains isolated from Egyptian agricultural soil which are efficient in biodegradation and mineralization of lignin. They were identified morphologically, microscopically and confirmed by RAPD profiles. Based on PCR amplification and sequencing of the 18S rDNA gene an analytical phylogenetic tree was drawn for species confirmation. The screening experiment revealed that Emericella nidulans, Aspergillus fumigatus, Phoma betae, Penicillium oxalicum and Humicola grisea exhibited maximum potential for high lignin degradation. They showed higher lignin peroxidase and laccase activities. By process optimization, enhanced lignin degradation (94%) was achieved within 7 days in lignin-glucose medium when compared with lignin degradation (70%) obtained in glucose-free medium. The ligninolytic enzymatic activities had a great potential for decolorization of chemically different synthetic dyes (Azure B, Safranin, Crystal Violet and Malachite Green). The highest enzymatic activities and the highest decolorization rates were detected at a dye concentration of 0.2 g/L. The dye decolorization rate significantly increased with tryptophan addition as (1 mmol/L). Humicola grisea showed the highest decolorization rate (99%) with azure B. Phoma beta also showed a high decolorization rate (99% with crystal violet and 90% with safranin). The observed activity enhancement resulted from the protective effect of tryptophan against H2O2 inactivation.

Effects of operational parameters of process UV radiation/hydrogen peroxide on decolorization of anthraquinone textile dye

The photodegradation of textile dye Reactive Blue 19, an anionic anthraquinone dye of reactive class, was investigated using UV radiation in the presence of H2O2 in UV reactor with low-pressure mercury lamps, with maximum energy output at the wavelength 254 nm. The effects of experimental variables, namely initial pH, initial dye concentration and concentration of peroxide were studied. The change of concentration of RB19 was followed by UV/vis spectrophotometric measurement of absorbance at 592 nm. The increase of the initial pH resulted in the efficiency increase of dye decolorization. The total decolorization was achieved in about 15 min. Results show that with the increase of dye concentration from 10 to 100 mg dm-3 the efficiency of process decreases. With the increase of the initial concentration of H2O2 from 10 to 30 mmol dm-3, the decolorization rate constant increased from 0.083 to 0.120 min1, with the decrease of process rate at the concentrations above. The highest decolorization rates were achieved at peroxide concentration of approx. 30 mmol dm-3, above which decolorization was inhibited by scavenging effect of peroxide. This study shows that UV/H2O2 process is promising treatment for dye RB 19 degradation in water and wastewater.

Photo-catalytic degradation of toxic dye amaranth on TiO 2/UV in aqueous suspensions

The photo-catalytic degradation of an azo dye − Amaranth (AM) – has been investigated in TiO 2/UV aqueous suspensions. The results obtained from the experiments during H 2O 2/TiO 2 addition show that the highest decolorization rate is provided by the combination of (UV + TiO 2 + H 2O 2). The decolorization efficiencies were 17%, 26%, 38% and 64% in the runs UV, UV + H 2O 2, UV + TiO 2 and (UV + TiO 2 + H 2O 2) after approximately 100 min illumination periods, respectively. The observed dye degradation rates followed pseudo-first order kinetics with respect to the substrate concentration under the experimental conditions used. Different experimental conditions, such as temperature, pH and presence of electron acceptor were investigated. The temperature effect was investigated at the range of 293–313 K and it was observed that decolorization rate increased by the increase in temperature. Chemical oxygen demand and dye absorbance of the photodegraded dye solution substantially decreased. Effect of pH was also investigated and it was observed that the lower the pH the higher the degradation. In addition, an enhancement in the photodegradation rate was observed by the addition of hydrogen peroxide as an electron acceptor. The adsorption trends of Amaranth at various initial concentrations followed the Langmuir isotherm trend. This work adds to the global discussion on the role of the advanced oxidation processes in water treatment.

Oxidation Decoloration Kinetics of C.I. Direct Blue 108 in Activated Oxygen Bleach Systems

The decoloration behaviors of C.I. Direct Blue 108 in two activated oxygen bleach systems (PB/TAED and PC/TAED) were investigated. It was found that the decoloration kinetics of the dye in the two systems followed the first-order kinetic model and the rate constants calculated by linear regression increased significantly with increasing temperature. The activation energies for the decoloration in PB/TAED and PC/TAED systems were 63.34 and 58.10 kJ/mol, respectively. Moreover, the highest decoloration rate constant was obtained at pH 9 in the two systems. The kinetic model had not changed with temperature and pH in the two systems.

Decoloration of Methylene Blue Via Mesoporous Silica Microspheres Doped with TiO&lt;sub&gt;2&lt;/sub&gt;

Mesoporous silica microsphere was prepared by microwave hydrothermal synthesis，using hexadecyl trimethyl ammonium bromide (CTAB) as template agent and tetraethylorthosilicate (TEOS) as silica source. And mesoporous silica microspheres doped with TiO2 was prepared by sol-gel method. They were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR) and N2 adsorption-desorption analysis. Then methylene blue decoloration test was investigated to verify the mechanism proposed elsewhere, with respect to concentration, amount of samples, pH and light illumination. Results indicate that low concentration, large amounts of samples, alkaline and UV illumination are more favorable to adsorption, and TiO2/MSM has higher decoloration rate than MSM.