Decolorization and degradation of acid dyes mediated by salt fractionated turnip ( Brassica rapa ) peroxidases

Peroxidases from turnip roots (524?U?g^?1 of vegetable) were highly effective in decolorizing acid dyes having wide spectrum chemical groups. Dye solutions, containing 40–170?mg?dye?L^?1, were treated by turnip peroxidases (TP) (specific activity of 122.0?U?mg^?1 proteins). These enzymes were able to decolorize most of the acid dyes in the presence of 2.0?mM 1-hydroxybenzotriazole (HOBT). Increasing concentration of enzyme and time in the absence of HOBT did not influence dye decolorization. The rate of decolorization was significantly enhanced when HOBT was added to the decolorizing solutions. The decolorization of all the used dyes was maximum at pH 5.0 and 40°C. Complex mixtures of dyes were significantly decolorized when treated with enzyme in the presence of HOBT (2.0?mM). Phytotoxicity test based on Allium cepa root growth inhibition has shown that majority of the TP-treated dye product were not more toxic than their parent dye. Kinetic parameters of the TP with various dyes showed that this enzyme has highest affinity for Acid Yellow 42. This study demonstrates that the peroxidase/mediator system was an effective biocatalyst for the treatment of industrial effluents from textile, dye manufacturing, dyeing and printing industries or complex mixtures of dyes.     

Decolorization of azo dyes by a salt-tolerant Staphylococcus cohnii strain isolated from textile wastewater

The salt-tolerant Staphylococcus cohnii strain, isolated from textile wastewater, has been found effective on decolorizing several kinds of azo dyes with different structures. The optimal conditions for azo dye acid red B (ARB) decolorization by S. cohnii were determined to be pH = 7.0 and 30°C. The decolorization efficiency increased with the increase of the salinity concentration, and around 90% of ARB (100 mg·L^?1) could be decolorized in 24 h when the salinity concentration was up to 50 g·L^?1. Moreover, the strain could still decolorize 19% of ARB in 24 h even when the NaCl concentration was increased to 150 g·L^?1. Meanwhile, the dependence of the specific decolorization rate by S. cohnii on the ARB concentration could be described with Michaelis-Menten kinetics (K _m = 585.7mg·L^?1, V _max = 109.8 mg·g cell^?1·h^?1). The addition of quinone redox mediator, named 2-hydroxy-1,4-naphthoquinone and anthraquinone-2,6-disulfonate, significantly accelerated the decolorization performance of S. cohnii. Furtherly, the activities of azoreductase (0.55 ??mol·mg protein^?1·min^?1) and Nicotineamide adenine dinucleotide-dichlorophenol indophenol (NADH-DCIP) reductase (8.9 ??mol·mg protein^?1·min^?1) have been observed in the crude cell extracts of S. cohnii. The decolorization products of ARB were analyzed by HPLC-MS, and the results indicated the reductive pathway was responsible for azo dye decolorization by S. cohnii.     

Evaluation of kinetics and energy consumption of the electrochemical oxidation of Acid Red 73 in aqueous media

A laboratory scale, undivided electrolysis cell with platinum anode and cathode was used for electrochemical oxidation of the azo dye Acid Red 73 in simulated wastewater. The influence of the supporting electrolyte, applied voltage, pH, initial dye concentration and temperature was studied, and decolorization was monitored by UV/Vis spectroscopy. Energy consumption, current efficiency and the electric energy per order have been also determined. With NaCl (1.5 g L^?1) as supporting electrolyte, at a voltage of 6 V, at neutral pH (6.9) and at 25 °C, the solution of the dye (50 mg L^?1) was completely decolorized within 15 min. The apparent activation energy for electrochemical decolorization was determined as ?1.9 kJ mol^?1.     

Biological Decolorization of C.I. Basic Green 4 Solution by Chlorella sp.： Effect of Operational Parameters

In recent years, the ability of microorganisms to decolorize textile wastewater has received great attention due to the environmental persistence and toxicity of these pollutants. In this paper biological decolorization of triphenylmethane dye, C.I. Basic Green 4 (BG 4), by Chlorella species was investigated. The effect of operational parameters (temperature, pH, initial dye concentration and algal concentration) on decolorization efficiency was examined. Results indicated that the desired initial pH was 9. The stability and efficiency of the algae in long-term repetitive operations were also examined. Michaelis-Menten kinetics was employed to describe the apparent correlation between the decolorization rate and dye concentration. The optimal kinetic parameters, Vmax (specific decolorization rate) and Km (maximum specific decolorization rate) were 4.6 mg dye g cell-1 h-1and 151.0 mg L-1, respectively. Fig 10, Tab 2, Ref24     

JAZ型絮凝剂对活性染料的絮凝效果

本文介绍了新近开发的ＪＡＺ絮凝凝剂地水样中活性艳红Ｋ－２ＢＰ，活性紫Ｈ－２Ｒ和活性黑Ｋ－ＢＲ染料的絮凝效果及ＰＨ值和投药比对脱色率的影响。在中性和弱酸性中絮凝效果好。投药比增大脱色率增加。对活性艳红和活性紫，起始浓度增加则达到８８．５％脱色率的投药比降低。对三种活性染料配水和活性 染料配水和活性黑染料生产水脱色率均可达到９９％，处理液残余色度在２０倍以下。     

高锰酸钾对染料废水的脱色研究

研究了影响高锰酸钾对染料废水脱色的有关因素,结果表明,脱色反应的最佳ＰＨ值应小于１．５,高锰酸钾的浓度对脱色效果显著。     

Photodegradation of an azo dye by silver-doped nano-particulate titanium dioxide

The synthesis of silver doped nano-particulate titanium dioxide (Ag/TiO₂) using a microemulsion method and an investigation of its photocatalytic activity for the degradation of Acid Red 27 in distilled water under UV-irradiation is reported. The prepared Ag/TiO₂ is characterized using transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. The size of the Ag nanoparticles is around 5–15?nm, with almost uniform distribution on the TiO₂ particles. The efficiency of the photocatalytic process is evaluated to establish the optimum conditions, found to be at 2?wt% of Ag loading on TiO₂, catalyst dosage of 400?mg?L^?1, and calcination temperature of 300°C. Complete decolorization of the dye solution on Ag/TiO₂ was observed in 20?min of UV irradiation in the optimum conditions.     

Anaerobic decolorization of an azo dye by a mixed culture

Wool dyeing wastewater contains xenobiotic compounds that can be removed by biotechnological processes. Studies on various dyes showed that anaerobic processes are suitable to alter azo dyes as a first step of the biodegradation process. These compounds are reduced by anaerobic consortia to aromatic amines and its ultimate degradation can be achieved by a further aerobic treatment.

Studies on degradation rate of an wool acid dye were performed in batch systems inoculated with anaerobic biomass. A commercial diazo dye, Acid Red 73, was added to the synthetic medium in which glucose was used as sole carbon source.

Results indicated that the Acid Red 73 was partially degraded by a mixed culture of anaerobic bacteria and a decolorization of 90% was obtained. Kinetics studies on removal of the colour showed that the decolorization rate was several times faster than the degradation rate of glucose for a range of dye concentrations between 60 mg/L and 400 mg/L. A first order kinetic model was used for dye concentrations up to 200 mg/L. For higher concentrations a model similar to the Michaelis‐Menten equation was better fitted to the experimental data.     

金属离子协同马尾藻对水中偶氮染料分子脱色的研究

本文研究了多种金属离子对海藻处理不同结构的偶氮染料分子的影响，结果表明，金属离子的种类及浓度对海藻处理偶所染料都有重要的作用，偶氮染料的分子量和结构也影响该体系的脱色效果。适当浓度的金属离子和海藻的体系比单独海藻处理偶氮染料的脱色速度快，脱色率高。同时探讨了该体系处理不同结构染料分子的脱色差异。     

Selection and development of efficient consortia for decolorization of metal complex dyes

Decolorization of 18 different metal complex acid dyes was studied with 11 bacterial consortia. Five consortia and five dyes were selected on the basis of maximum decolorization. Among the parameters for optimization, nutrient broth was preferred by all bacterial consortia but one of them showed significant decolorization with Bushnell and Haas medium with or without glucose and yeast extract; hence, this consortium was selected for further studies. Decolorization efficiency was adversely affected beyond 200 mg/L dye and 2% NaCl concentration. Treatment efficiency was increased 2-fold using a developed consortium as compared to original consortium. Changes in the UV-Vis spectra and considerable reduction in chemical oxygen demand of selected metal complex dyes after decolorization prove the efficiency of the consortium for its use. Decolorization of a broad range of metal complex dyes at pH 7.5 ± 0.5, 35 ± 2 °C, and static conditions promises the use of the developed consortium for industrial wastewater treatment.     

NKY功能化树脂静态吸附混合染料的研究

探讨了NKY功能化树脂对混合染料(活性艳蓝：KN-R和活性艳橙K-GN)的静态吸附行为．结果表明：NKY树脂吸附单组分染料的能力大于其对混合染料的吸附，而且对混合体系中的染料有一定的选择性，吸附KN-R的速率较大．从动力学研究来看，NKY对混合染料的吸附速率其决定步骤是液膜扩散．等温曲线的结果显示，NKY对混合染料中每种组分的吸附行为同吸附单组分体系的类似，同时，随温度的升高，吸附速率常数增大，标准自由能变的绝对值增大。     

High adsorption of dyes by water hyacinth fixed on alginate

Pollution from synthetic dyes has emerged to be a significant environmental issue over the past few decades. This has mainly been triggered by the increasing global dye production, possible toxic effects, undesirable colour and high persistence in the environment. Biosorption, which involves dye removal from aqueous solution by passive linkage in live and dead biomass, has shown great potential in removing dyes from aquatic environments. Among aquatic macrophytes, water hyacinth, Eichhornia crassipes, has shown great potential as a biosorbent. In this work, we investigated the removal of two basic dyes, methylene blue and crystal violet, using E. crassipes immobilized on alginate. Results showed that the Langmuir model better described the equilibrium sorption data when compared to the Freundlich model. Optimum amounts of methylene blue and crystal violet dyes were adsorbed in the alkaline pH range (8–10), 8 % biomass dose, and the amount of dye removed increased with increasing initial dye concentration. The equilibrium monocomponent adsorption capacities for the dyes were 111.1 and 43.5 mg/g, while the binary adsorption capacities were 26.1 and 11.6 mg/g for methylene blue and crystal violet, respectively. To conclude, we show for the first time that E. crassipes fixed on alginate beads can uptake and adsorb methylene blue and crystal violet dyes very effectively in batch systems and show great potential for dye removal from aquatic environments.     

Toxicity of cadmium nanoparticles to Bacillus subtilis

The study deals with the toxicological impact of cadmium nanoparticles (Cd NPs) on Bacillus subtilis as a model Gram-positive bacterium. Cadmium oxide (CdO) NPs (～22 nm) and cadmium sulfide (CdS) NPs (～3 nm) were used in this study. Both the NPs were found to inhibit the cell viability of B. subtilis when added to the culture at mid-log phase, the viable cell number declined with increasing concentration of Cd NPs. At mid-log phase, 15 mg L^?1 CdO NPs inhibited growth by ～50%, whereas at 30 mg L^?1 growth completely ceased. Under the same conditions, CdS NPs inhibited growth by ～50% at a concentration of 8 mg L^?1, and at 20 mg L^?1 growth was completely retarded. The cells changed their morphological features to a filamentous form with increasing Cd NPs exposure time, leading to associated with clumping. NPs treated cells when stained with 4′, 6-diamino-2-phenylindole, showed filamentous multinucleated bead structure, suggesting irregularities in cell division. Increasing intracellular oxidative stress due to Cd NPs exposure might be one of the reasons for the cell morphological changes and toxicity in B. subtilis.     

BDE-47对人胚肾细胞HEK293的毒理效应及作用机制

2,2’,4,4’-四溴联苯醚(BDE-47)是生物体中含量最高且毒性最强的PBDEs之一,有关BDE-47对肾细胞的毒性及其作用机制的研究仍有待补充。选取3个剂量组(低:10-6mol·L-1、中:10-5mol·L-1、高:10-4mol·L-1)及溶剂对照组,研究了BDE-47对人胚肾细胞(HEK293)的细胞凋亡率及活性氧(ROS)水平的影响;并从分子水平对细胞氧化损伤、凋亡相关蛋白(APE1及p53)及凋亡相关基因m RNA(p53、Bax、Caspase 3、Caspase 8)的表达量进行测定。实验结果显示:与对照组相比,中、高剂量组细胞凋亡率显著增加(P0.05);ROS水平在中剂量组显著上升(P0.01);随BDE-47浓度的变化,APE1蛋白表达量与细胞ROS水平存在一致性;p53、Bax、Caspase 8 m RNA表达量与BDE-47的浓度间存在剂量-效应关系。结果表明,BDE-47可诱导HEK293细胞凋亡及氧化应激,APE1可能是细胞ROS升高与细胞凋亡间重要的中介因子;BDE-47可以通过影响Caspase 8及线粒体途径中p53及Bax的表达诱导细胞凋亡。     

黄孢原毛平革菌对固体介质中染料的降解反应

用黄孢原毛平革菌(Phanerochaetechrysosporium)3品系在固体介质中建立染料的降解反应体系,分光光度法测定染料的脱色降解率。黄孢原毛平革菌在琼脂、沙子及土壤等固体介质中均能有效地降解偶氮染料、蒽醌染料及聚合染料;植物材料玉米芯和木屑可作为共代谢碳源被该菌利用;BKM F 1767菌种降解能力最强,对活性艳蓝KN R的进攻性优于对PolyR 478和比布列希猩红。     

Decolorisation of Acid Blue 74 by ultraviolet/H<Subscript>2</Subscript>O<Subscript>2</Subscript>

The photodegradation of Acid blue 74 in aqueous solution employing a H₂O₂/ultraviolet system in a photochemical reactor was investigated. The kinetics of decolorization were studied by application of a kinetic model. The results show that the reaction of decolorization followed pseudo-first order kinetics. We demonstrate that there is an optimum H₂O₂ concentration, at which the rate of the decolorization reaction is maximum. Irradiation at 253.7 nm of the dye solution in the presence of H₂O₂ results in complete discoloration after ten minutes of treatment.     

壳聚糖/膨润土复合絮凝剂处理染料废水的研究

利用壳聚糖/钠基膨润土复合絮凝剂对活性艳红X3B等11种染料模拟废水及实际印染废水进行絮凝脱色处理。考察了复合絮凝剂投加量、pH值、搅拌速率、搅拌时间等因素对模拟染料废水絮凝脱色的影响。结果表明,在染料浓度为100 mg.L-1,pH为5的条件下,复合絮凝剂投加量为1.25 g.L-1时,3种质量比的复合絮凝剂对活性艳红X3B的脱色率分别达到75%、90%和97%以上;质量比为1∶10的壳聚糖/钠基膨润土复合絮凝剂,对其它活性、还原性、分散性、水溶性等8种印染厂常用染料也具有很好的絮凝脱色作用,脱色率均可达94%以上。对印染废水处理厂进水口废水和经过A/O处理后废水的色度去除率和COD去除率分别可以达到81.05%、83.74%和53.21%、41.22%,具有一定的应用前景。     

Modeling of adsorption kinetics and equilibria of acid dyes onto activated carbon in single- and binary-component systems

Adsorptive removal of Acid Blue 127 and Acid Yellow 17 from their single and binary solutions has been studied using powdered activated carbon (PAC). The dyes used extensively for dying of nylon fiber in textile industry are known as Nylomine Blue P-B (NB) and Nylomine Yellow P-4G (NY), respectively. Time-dependent results obtained from single-component system have been better predicted by two resistance diffusion model rather than homogeneous surface diffusion. The magnitudes of film- and intraparticle diffusion coefficients calculated from McKay equation are ～10^?9 and ～10^?15 m² s^?1, whereas surface diffusion coefficients have been estimated as ～10^?13 m² s^?1 using Vermeulen approximation. Experimental equilibrium isotherms have been evaluated by changing initial dye concentrations in the range of 0.02–1.00 of mmol L^?1. Freundlich isotherm parameters for individual solutions of the dyes have been used to predict their equilibrium behaviors in binary solutions by applying extended Freundlich model. Langmuir isotherm model and its extended form have also been fitted to the data for single- and binary-dye solutions, respectively. Thermodynamic functions derived from the temperature dependence of adsorption equilibrium constants in 298–318 K range show that adsorption processes are endothermic but spontaneous.     

Effects of nonylphenol on ovarian cancer cells PEO4 c-myc and p53 mRNA and protein expression

The molecular mechanisms underlying proliferation and apoptosis induced by p-nonylphenol (NP) through regulation of mRNA and protein expression of c-myc, p53 mRNA and the protein was investigated using ovarian cancer PEO4 cells. PEO4 cells were grown in the Dulbecco's modified Eagle medium (DMEM), 3(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay was employed to investigate cell proliferation. RT-PCR and immunohistochemistry was performed to determine mRNA and protein expression of PEO4 c-myc and p53. Within the range of approximately 8–9×10^?7 mol L^?1, NP stimulated proliferation in PEO4 cells in a concentration-and time-dependent manner. RT-PCR and immunohistochemistry analyses revealed that treatment with 32 × 10^?7 mol L^?1 NP for 72 hr resulted in increased mRNA and protein expression of PEO4 c-myc and p53. Evidence indicates that NP exerted estrogenic actions and stimulated proliferation in estrogen responsive ovarian cancer PEO4 cells by up-regulation of c-myc mRNA and protein expression.     

Development of a complex-based flow injection spectrophotometric method for determination of the herbicide pinoxaden in environmental samples

A flow injection (FI) spectrophotometric method for the determination of the herbicide pinoxaden (PXD) has been proposed. PXD was converted in alkaline media with hydroxylamine hydrochloride to the hydroxamate salt. The salt was reacted with iron(III) chloride, and the absorbance of the red colored tris iron hydroxamate complex was measured at 500?nm using a FI system. The method was found to be linear between 0.5 and 40?mg?L^?1 with a molar absorptivity of 1.53?×?10^4?L?mol^?1?cm^?1. The limit of detection and limit of quantification were found to be 0.1?±?0.01?mg?L^?1 and 0.6?±?0.05?mg?L^?1, respectively. Any interference of fenoxaprop-p-ethyl (FE) was avoided by the separation of PXD by liquid chromatography with a mixture of dichloromethane and n-hexane (1?:?1) as eluent. The method was applied to the determination of PXD in soil, water, and wheat grains with percent recoveries of 98?±?2, 100?±?2, and 98?±?5, respectively. Sample throughput of 60 samples per hour was achieved under optimized conditions.