Decolorization of synthetic dyes using a copper complex with glucaric acid

Selected azo, acridine, triphenyl methane, anthraquinone and thiazine-based dyes were decolorized using a catalytic system consisting of Cu(II)/glucaric acid/H(2)O(2). More than 90% decolorization was obtained with 100 ppm Acridine Orange, Azure B, Chicago Sky Blue, Crystal Violet, Methyl Orange, Poly B-411, Reactive Black 5, Reactive Blue 2, and Remazol Brilliant Blue R within 24 h. Seventy to eighty percent decolorization was achieved within the first 6 h. The decolorizaton was not affected by pH. The involvement of hydroxyl radicals produced in the system in the decolorization of the dye molecules was confirmed by electron spin resonance study.     

Microbial decolorization of synthetic dyes and reactive dyes of industrial effluents by using a novel fungus Aspergillus proliferans

A decolorizing fungal strain was isolated and identified by the morphology and genotypic characterization as Aspergillus proliferans. The effect of A. proliferans on decolorization of synthetic dyes (70 mg ml(-1)) and colored effluent was evaluated in liquid culture medium. A. proliferans expressed their effective decolorization activity in effectual decolorization of synthetic dyes and industrial effluent. Synthetic dyes were decolorized by 76 to 89% within 6 days of treatment and 73.5% of color was removed in industrial effluent within 8 days. The addition of optimum carbon and nitrogen sources were effectively stimulated the decolorization activity. The high concentration of glucose repressed the decolorization activity and supplementation of yeast extract has significantly enhanced the effluent decolorization at p < 0.05. Laccase enzyme was isolated from liquid state fermentation, which showed significant enzyme activity (10,200 Uml(-1)) at p < 0.005. The crude enzyme decolorizes the dyes aniline blue and congo red in 14 hours (40.9 to 70%) and the effluent in 14 hours (88.6%). Moreover, the culture free supernatant without the fungal biomass has also effectively decolorized the effluent and synthetic dyes. The fungi Aspergillus proliferans was used not only for decolorization but also for better bioremediation of industrial effluent.     

Degradation of dyes from aqueous solution by Fenton processes: a review

Several industries are using dyes as coloring agents. The effluents from these industries are increasingly becoming an environmental problem. The removal of dyes from aqueous solution has a great potential in the field of environmental engineering. This paper reviews the classification, characteristics, and problems of dyes in detail. Advantages and disadvantages of different methods used for dye removal are also analyzed. Among these methods, Fenton process-based advanced oxidation processes are an emerging prospect in the field of dye removal. Fenton processes have been classified and represented as “Fenton circle”. This paper analyzes the recent studies on Fenton processes. The studies include analyzing different configurations of reactors used for dye removal, its efficiency, and the effects of various operating parameters such as pH, catalyst concentration, H₂O₂ concentration, initial dye concentration, and temperature of Fenton processes. From the present study, it can be conclude that Fenton processes are very effective and environmentally friendly methods for dye removal.     

Degradation of azo dyes by algae

The degradation of azo dyes by algae was evaluated and it was found that certain algae can degrade a number of azo dyes to some extent. The reduction rate appears to be related to the molecular structure of the dyes and the species of algae used. The azo reductase of algae is responsible for degrading azo dyes into aromatic amine by breaking the azo linkage. The aromatic amine is then subjected to further metabolism by algae. It is proposed in this paper that in stabilization ponds, algae can play a direct role in the degradation of azo dyes, rather than only providing oxygen for bacterial growth.     

Organochlorines and endometriosis: a mini-review

Organochlorines (polychlorinated biphenyls and dioxin-like compounds) are suspected to play a role in the etiopathogenesis of endometriosis. This hypothesis, based on experimental data, has been circulating for years in the scientific community and several epidemiologic surveys have attempted to obtain confirmatory human data. The purpose of this mini-review is to provide an overview of the twelve epidemiological studies that have assessed the relationship between endometriosis and organochlorine exposure. Several studies did not observe a significant association between peritoneal endometriosis and organochlorines. The deep nodular form of endometriosis appears associated with a higher serum level of both dioxin-like compounds and polychlorobiphenyls. The type of control women, the nature of the chemicals measured, and the definition of the disease could modulate the ability to detect the possible relationship between endometriosis and organochlorine exposure.     

Degradation of azo dyes using low iron concentration of Fenton and Fenton-like system

This study investigated Fenton and Fenton-like reactions at low iron concentration (相似文献   

Copper-ligand complex for the decolorization of synthetic dyes

The reaction system containing Cu(II), hydrogen peroxide and D-arabinono-1,4-lactone was found to be effective in the decolorization and reduction of toxicity of azo, thiazine-, triphenylmethane- and anthraquinone-based synthetic dyes. More than 85% decolorization was obtained with 100ppm Acridine Orange, Azure B, Chicago Sky Blue 6B, Crystal Violet, Evans Blue, Poly B-411, Reactive Blue 2, Reactive Blue 5, and Remazol Brilliant Blue R incubated for 24h in the presence of 10mM CuSO(4), 20mM D-arabinono-1,4-lactone and 80 mM H(2)O(2). The rate of decolorization was not affected by pH in the range of 3-9. The rapid decolorization was accompanied by a fast decomposition of H(2)O(2) in the reaction mixture and by a fast production of hydroxyl radicals.     

Electrochemical removal of synthetic textile dyes from aqueous solutions using Ti/Pt anode: role of dye structure

In this work, the efficiency of electrochemical oxidation (EO) was investigated for removing a dye mixture containing Novacron Yellow (NY) and Remazol Red (RR) in aqueous solutions using platinum supported on titanium (Ti/Pt) as anode. Different current densities (20, 40 and 60 mA cm^?2) and temperatures (25, 40 and 60 °C) were studied during electrochemical treatment. After that, the EO of each of these dyes was separately investigated. The EO of each of these dyes was performed, varying only the current density and keeping the same temperature (25 °C). The elimination of colour was monitored by UV-visible spectroscopy, and the degradation of organic compounds was analysed by means of chemical oxygen demand (COD). Data obtained from the analysis of the dye mixture showed that the EO process was effective in colour removal, in which more than 90 % was removed. In the case of COD removal, the application of a current density greater than 40 mA cm^?2 favoured the oxygen evolution reaction, and no complete oxidation was achieved. Regarding the analysis of individual anodic oxidation dyes, it was appreciated that the data for the NY were very close to the results obtained for the oxidation of the dye mixture while the RR dye achieved higher colour removal but lower COD elimination. These results suggest that the oxidation efficiency is dependent on the nature of the organic molecule, and it was confirmed by the intermediates identified. Figure

Chemical structures of a NY and b RR     

Decolorization of structurally different synthetic dyes using cobalt(II)/ascorbic acid/hydrogen peroxide system

The cobalt(II)/ascorbic acid/hydrogen peroxide system was used for decolorization of azo, acridine, anthraquinone, thiazine and triphenylmethane dyes. More than 90% decolorization was obtained with all dyes except Remazol Brilliant Blue R (75%). With other transition metals the system was less efficient. With copper, higher concentration and prolonged incubation time was necessary to obtain the same extent of decolorization. The rate of decolorizaton was not affected by pH in the range of 3-9. The reaction is very fast, with more than 90% decolorization being attained within 15 min. The system produces hydroxyl radicals which are responsible for the decolorization.     

Degradation of dyes in aqueous solutions by the Fenton process

Degradation of 20 different dyes in aqueous solutions by the Fenton process was performed. These dyes include 6 types: acidic, reactive, direct, cationic, disperse and vat dyes. The former four types of dyes were decolorized and their TOC values were decreased greatly, while the color and TOC removals of the latter two types were lower. The catalytic activities of four metal ions on the degradation efficiencies of Vat Blue BO, which was chosen as a model dye because of its lowest color and TOC removals, were compared in the dark and under the ultraviolet light irradiation. The catalytic ability of different metals was Fe2+>Cu2+>Mn2+>Ag+ in the dark, and the same sequence was obtained under irradiation condition with greater degradation efficiency. Furthermore, the efficiencies of three oxidation processes, including H2O2/UV, Fe2+/H2O2 and Fe2+/H2O2/UV were compared. The results showed that the oxidation by Fe2+/H2O2/UV was the strongest, and even greater than the arithmetic sum of the other two processes, which suggests the synergistic effect of ultraviolet and ferrous ions on the degradation reaction.     

Decolourization of synthetic dyes by Trametes hirsuta in expanded-bed reactors

The present paper studies the decolourization of different synthetic dyes (Indigo Carmine, Bromophenol Blue, Methyl Orange and Poly R-478) by the white-rot fungus Trametes hirsuta at bioreactor scale under solid-state conditions, operating with ground orange peelings as a support-substrate. Dye decolourization was performed in both batch and continuous mode. Batch cultivation led to high decolourization percentages in a short time (100% for Indigo Carmine in 3h and 85% for Bromophenol Blue in 7 h). As for continuous cultivation, different hydraulic retention times (HRT) were studied (0.8, 1, 1.5 and 3d). The highest decolourization percentages were obtained operating at a HRT of 3d, especially for the dyes Methyl Orange and Poly R-478 (81.4% and 46.9%, respectively). This is a very interesting result, since there are few studies dealing with the continuous decolourization of dyes at bioreactor scale by fungal laccases.     

Degradation of the textile dyes Basic yellow 28 and Reactive black 5 using diamond and metal alloys electrodes

Basic yellow 28 (SLY) and Reactive black 5 (CBWB), which are respectively methine and sulfoazo textile dyes were individually exposed to electrochemical treatment using diamond-, aluminium-, copper- and iron-zinc alloy electrodes. The generated current was registered with time during electrolysis of the dye solutions and the color variation and the formation of degradation products were followed using HPLC with diode array detection. Four different electrodic materials were tested by applying different potentials in the range -1.0 to -2.5 V and presented 95% color removal and COD removal of up to 65-67% in the case of CBWB dye solution treated with the copper and iron electrodes. Efficiency was enhanced with stirring and flow in relation to the stationary regime. The kinetic parameter reaction rate was used to establish the effect of flow, potential, electrode nature and pH. The formation and characterization of the precipitate formed under certain conditions is reported and discussed.     

Green synthesis of recyclable iron oxide nanoparticles using Spirulina platensis microalgae for adsorptive removal of cationic and anionic dyes

Environmental Science and Pollution Research - Globally, organic dyes are major constituents in wastewater effluents due to their large-scale industrial applications. These persistent pollutants...     

聚多巴胺包覆的Fe3O4去除水体中的染料

多巴胺作为海洋贝类生物分泌的粘附蛋白的模拟小分子物质,在典型的海洋环境条件下能够发生自聚合反应覆盖到不同基质上.通过多巴胺的自聚合在磁性纳米Fe3O4表面包覆一层聚合多巴胺(PDA),得到Fe3O4/PDA复合材料.材料的热重分析,磁滞回线,透射电镜,红外光谱等表明PDA包覆到了Fe3O4的表面.PDA具有丰富的酚羟基和氨基,可以通过络合、配位、氢键、π-π堆积等多种作用与其他物质结合.采用亚甲基蓝和日落黄染料作为目标物考察Fe3O4/PDA的吸附性能.研究表明,溶液pH对2种染料的吸附有显著的影响,随溶液pH的升高,阳离子染料亚甲基蓝的吸附容量显著增大,而阴离子染料日落黄吸附容量明显下降.由Langmuir吸附等温模型拟合出亚甲基蓝、日落黄的最大吸附容量分别为204.1和100.0 mg/g.动力学研究表明,这2种染料的吸附能够快速达到平衡.     

水体中酮硝基麝香的臭氧氧化降解研究

采用臭氧氧化水体中的酮硝基麝香,考察pH、H2O2等因素对降解程度的影响,结果表明提高初始pH能加快酮硝基麝香的氧化降解,当pH为12时,反应时间1 h,酮硝基麝香几乎完全去除,浓度为2 mol/L和5 mol/L的H2O2存在有利于O3分解生成·OH自由基,使得酮硝基麝香的氧化降解速率加快,当H2O2浓度超过5 mol/L,H2O2会成为·OH的清除剂,降低·OH利用率;无论O3单独作用和O3/H2O2协同作用,酮硝基麝香降解符合准一级动力学规律;酮硝基麝香氧化降解产物包括甲酸、二乙酸和硝酸根等,其中硝基从苯环上脱落降低了硝基麝香对环境的风险.     

Biofiltration kinetics of a gaseous aldehyde mixture using a synthetic matrix

Although aldehydes contribute to ozone and particulate matter formation, there has been little research on the biofiltration of these volatile organic compounds (VOCs), especially as mixtures. Biofiltration degradation kinetics of an aldehyde mixture containing hexanal, 2-methylbutanal (2-MB), and 3-methylbutanal (3-MB) was investigated using a bench-scale, synthetic, media-based biofilter. The adsorption capacity of the synthetic media for a model VOC, 3-methylbutanal, was 10 times that of compost. Periodic residence time distribution analysis (over the course of 1 yr) via a tracer study (84-99% recovery), indicated plug flow without channeling in the synthetic media and lack of compaction in the reactor. Simple first-order and zero-order kinetic models both equally fit the experimental data, yet analysis of the measured rate constants versus fractional conversion suggested an overall first-order model was more appropriate. Kinetic analysis indicated that hexanal had a significantly higher reaction rate (k = 0.09 +/- 0.005 1/sec; 23 +/- 1.3 ppmv) compared with the branched aldehydes (k = 0.04 +/- 0.0036 1/sec; 31 +/- 1.6 ppmv for 2-MB and 0.03 +/- 0.0051 1/sec; 22 +/- 1.3 ppmv for 3-MB). After 3 months of operation, all three compounds reached 100% removal (50 sec residence time, 18-46 ppmv inlet). Media samples withdrawn from the biofilter and observed under scanning electron microscopy analysis indicated microbial growth, suggesting removal of the aldehydes could be attributed to biodegradation.     

Extraction of arsenic in a synthetic arsenic-contaminated soil using phosphate

An environment-friendly and cost-effective extraction method has been studied for the removal of arsenic from contaminated soil. A yellow-brown forest soil was contaminated with arsenic(V) and used as a model soil. Among various potassium and sodium salts, potassium phosphate was most effective in extracting arsenic, attaining more than 40% extraction in the pH range of 6–8 with minimum damage to the soil properties. Exchange mechanism is proposed for the extraction of arsenic from soil by phosphate. Sequential extraction shows that phosphate is effective in extracting arsenic of Al- and Fe-bound forms. Arsenic of residual form was not extracted. Arsenic was efficiently extracted by phosphate solution of pH 6.0 at 300 mM phosphate concentration and at 40°C.     

Acid dyes removal using low cost adsorbents

Dyestuff production units and dyeing units have always had pressing need techniques that allow economical pre-treatment for colour in the effluent. The effectiveness of adsorption for dye removal from wastewaters has made it an ideal alternative to other expensive treatment options. Removal of acid green 25 and acid red 183 from aqueous solution by different adsorbent such as shells of almond and hazelnut, and poplar and walnut sawdust were investigated. Equilibrium isotherms have been determined and analysed using the Freundlich equations. Parameters of Freundlich isotherm have been determined using adsorption data. Capacities of adsorbent follow as walnut > poplar > almond > hazelnut for AG25 and almond > walnut > poplar > hazelnut for AR183, respectively.     

Utilization of coal fly ash in China: a mini-review on challenges and future directions

Environmental Science and Pollution Research - The rapid economic development in China places a large demand for energy, and as a result, thermal power plants in China are producing an enormous...     

Extraction of Sudan dyes from environmental water by hemimicelles-based magnetic titanium dioxide nanoparticles

A novel method for the extraction of Sudan dyes including Sudan I, II, III, and IV from environmental water by magnetic titanium dioxide nanoparticles (Fe₃O₄@TiO₂) coated with sodium dodecylsulfate (SDS) as adsorbent was reported. Fe₃O₄@TiO₂ was synthesized by a simple method and was characterized by transmission electron microscopy, Fourier-transform infrared spectrometry, and vibrating sample magnetometer. The magnetic separation was quite efficient for the adsorption and desorption of Sudan dyes. The effect of the amount of SDS, extraction time, pH, desorption condition, maximal extraction volume, and humic acid on the extraction process were investigated. This method was employed to analyze three environmental water samples. The results demonstrated that our proposed method had wide linear range (25–5,000 ng L^?1) with a good linearity (R ²?>?0.999) and low detection limits (2.9–7.3 ng L^?1). An enrichment factor of 1,000 was achieved. In all three spiked levels (25, 250, and 2,500 ng L^?1), the recoveries of Sudan dyes were in the range of 86.9–93.6 %. The relative standard deviations obtained were ranging from 2.5 to 9.3 %. That is to say, the new method was fast and effective for the extraction of Sudan dye from environmental water.